Contributors

Andrew Duncombe

S J Machin

Consultant Haematologist, Southampton University Hospitals

Professor of Haematology, Department of Haematology,

NHS Trust, Southampton

University College London Hospitals NHS Trust, London

Tyrrell G J R Evans

G M Mead

Senior Lecturer, Department of General Practice and

Consultant in Medical Oncology, Wessex Medical Oncology

Primary Care, King’s College School of Medicine and Dentistry,

Unit, Southampton University Hospitals NHS Trust,

London

Southampton

T Everington

Adrian C Newland

Specialist Registrar, Department of Haematology, University

Professor of Haematology, Department of Haematology, Bart’s

College London Hospitals NHS Trust, London

and the London, Queen Mary’s School of Medicine and

Dentistry, London

Adele K Fielding

Senior Associate Consultant and Assistant Professor in

David G Oscier

Medicine, Molecular Medicine Program and Division of

Consultant Haematologist, Department of Haematology and

Hematology, Mayo Clinic, Rochester, MN, USA

Oncology, Royal Bournemouth Hospital, Bournemouth, and

Honorary Senior Lecturer, University of Southampton

John Goldman

Professor of Haematology, Imperial College School of

F E Preston

Medicine, Hammersmith Hospital, London

Professor of Haematology, Royal Hallamshire Hospital,

Sheffield

A H Goldstone

Consultant Haematologist, Department of Haematology,

Drew Provan

University College London Hospitals NHS Trust, London

Senior Lecturer, Department of Haematology, Bart’s and

the London, Queen Mary’s School of Medicine and Dentistry,

Anthony R Green

London

Professor of Haemato-Oncology, Department of Haematology,

Cambridge Institute for Medical Research, Cambridge

Stephen J Russell

Director, Molecular Medicine Program, Mayo Foundation,

K K Hampton

Rochester, MN, USA

Senior Lecturer in Haematology, Royal Hallamshire Hospital,

Sheffield

Charles R J Singer

Consultant Haematologist, Royal United Hospital, Bath

Victor Hoffbrand

Emeritus Professor of Haematology and Honorary Consultant

George S Vassiliou

Haematologist, Royal Free Hospital Hampstead NHS Trust and

Leukaemia Research Fund Clinical Research Fellow/Honorary

School of Medicine, London

Specialist Registrar, Department of Haematology,

Cambridge Institute for Medical Research, Cambridge

R J Liesner

Consultant Haematologist, Department of Haematology and

Sir David J Weatherall

Oncology, Great Ormond Street Hospital for Children NHS

Regius Professor of Medicine Emeritus, Weatherall Institute of

Trust, London, and Department of Haematology,

Molecular Medicine, University of Oxford,

University College London Hospitals NHS Trust, London

John Radcliffe Hospital, Oxford

Preface

As with most medical specialties, haematology has seen major changes since this book was first published in

1998.

We now have greater understanding of the molecular biology of many diseases, both malignant and non-malignant. This new

knowledge has helped us to develop more sensitive assays for many conditions, and has been taken into the clinic, with the

engineering of new drugs, such as STI571 used in the treatment of chronic myeloid leukaemia, amongst others.

As with the first edition, the intention has been to encompass all aspects of haematology but with perhaps a greater emphasis on

basic science than previously. Readers will note that the writing team is almost identical to that for the first edition, which provides

continuity of style.

I would like to express my gratitude to all my haematology colleagues for updating their sections and bringing the entire text up

to date. Key reading lists are provided for all topics for those wishing to read about haematology in greater detail. Thanks must also

go to the BMJ and in particular Mary Banks, Senior Commissioning Editor, and Sally Carter, Development Editor, who have been

key players in the development of the second edition.

I would welcome any comments concerning the book, and perhaps readers may have suggestions for the next edition. I can be

contacted at a.b.provan@qmul.ac.uk.

vii

Iron deficiency anaemia

Drew Provan

Iron deficiency is the commonest cause of anaemia worldwide

Table 1.1 Daily dietary iron requirements per 24 hours

and is frequently seen in general practice. The anaemia of iron

deficiency is caused by defective synthesis of haemoglobin,

Male

1 mg

resulting in red cells that are smaller than normal (microcytic)

Adolescence

2-3 mg

and contain reduced amounts of haemoglobin (hypochromic).

Female (reproductive age)

2-3 mg

Pregnancy

3-4 mg

Infancy

1 mg

Maximum bioavailability from normal diet about

4 mg

Iron metabolism

Iron has a pivotal role in many metabolic processes, and the

Box 1.1 Risk factors in development of iron deficiency

average adult contains 3-5 g of iron, of which two thirds is in

• Age: infants (especially if history of prematurity);

the oxygen-carrying molecule haemoglobin.

adolescents; postmenopausal women; old age

A normal Western diet provides about 15 mg of iron daily,

• Sex: increased risk in women

of which 5-10% is absorbed (

1 mg), principally in the

• Reproduction: menorrhagia

duodenum and upper jejunum, where the acidic conditions

• Renal: haematuria (rarer cause)

help the absorption of iron in the ferrous form. Absorption is

• Gastrointestinal tract: appetite or weight changes; changes

helped by the presence of other reducing substances, such as

in bowel habit; bleeding from rectum/melaena; gastric or

bowel surgery

hydrochloric acid and ascorbic acid. The body has the capacity

• Drug history: especially aspirin and non-steroidal

to increase its iron absorption in the face of increased

anti-inflammatories

demand—for example, in pregnancy, lactation, growth spurts,

• Social history: diet, especially vegetarians

and iron deficiency.

• Physiological: pregnancy; infancy; adolescence; breast

Once absorbed from the bowel, iron is transported across

feeding; age of weaning

the mucosal cell to the blood, where it is carried by the protein

transferrin to developing red cells in the bone marrow. Iron

stores comprise ferritin, a labile and readily accessible source of

iron, and haemosiderin, an insoluble form found

predominantly in macrophages.

About 1 mg of iron a day is shed from the body in urine,

faeces, sweat, and cells shed from the skin and gastrointestinal

tract. Menstrual losses of an additional 20 mg a month and the

increased requirements of pregnancy (500-1000 mg) contribute

to the higher incidence of iron deficiency in women of

reproductive age.

Figure 1.1 Nail changes in iron deficiency anaemia (koilonychia)

Clinical features of iron deficiency

Box 1.2 Causes of iron deficiency anaemia

The symptoms accompanying iron deficiency depend on how

Reproductive system

rapidly the anaemia develops. In cases of chronic, slow blood

• Menorrhagia

loss, the body adapts to the increasing anaemia, and patients

Gastrointestinal tract

can often tolerate extremely low concentrations of

Bleeding

haemoglobin—for example,

70 g/l—with remarkably few

• Oesophagitis

symptoms. Most patients complain of increasing lethargy and

• Oesophageal varices

dyspnoea. More unusual symptoms are headaches, tinnitus, and

• Hiatus hernia (ulcerated)

• Peptic ulcer

taste disturbance.

• Inflammatory bowel disease

On examination, several skin, nail, and other epithelial

• Haemorrhoids (rarely)

changes may be seen in chronic iron deficiency. Atrophy of the

• Carcinoma: stomach, colorectal

skin occurs in about a third of patients, and (rarely nowadays)

• Angiodysplasia

nail changes such as koilonychia (spoon shaped nails) may

• Hereditary haemorrhagic telangiectasia (rare)

result in brittle, flattened nails. Patients may also complain of

Malabsorption

angular stomatitis, in which painful cracks appear at the angle

• Coeliac disease

of the mouth, sometimes accompanied by glossitis. Although

• Atrophic gastritis (also may result from iron deficiency)

uncommon, oesophageal and pharyngeal webs can be a feature

Physiological

• Growth spurts (especially in premature infants)

of iron deficiency anaemia (consider this in middle aged

• Pregnancy

women presenting with dysphagia). These changes are believed

Dietary

to be due to a reduction in the iron-containing enzymes in the

• Vegans

epithelium and gastrointestinal tract.

• Elderly

Tachycardia and cardiac failure may occur with severe

Worldwide commonest cause of iron deficiency is hookworm

anaemia irrespective of cause, and in such cases prompt

infection

remedial action should be taken.

ABC of Clinical Haematology

When iron deficiency is confirmed a full clinical history

Anaemia

including leading questions on possible gastrointestinal blood

Haemoglobin

<135 g/l (male)

loss or malabsorption (as in, for example, coeliac disease)

<115 g/l (female)

should be obtained. Menstrual losses should be assessed, and

What is mean cell volume?

the importance of dietary factors and regular blood donation

should not be overlooked.

Low (<76 fl)

Diet alone is seldom the sole cause for iron deficiency

microcytic red cells

anaemia in Britain except when it prevents an adequate

Consider:

response to a physiological challenge—as in pregnancy, for

Iron deficiency anaemia

example.

Thalassaemia

Anaemia of chronic disorders

History and physical examination

Laboratory investigations

Obvious source of blood loss?

A full blood count and film should be taken. These will

(eg menstrual or gastrointestinal (GI) tract)

confirm the anaemia; recognising the indices of iron deficiency

Yes

is usually straightforward (reduced haemoglobin

Investigation:

Treat underlying cause or

concentration, reduced mean cell volume, reduced mean cell

Full blood count and film examination

consider specialist referral

haemoglobin, reduced mean cell haemoglobin concentration).

Serum ferritin estimation

Urea, electrolytes, and liver function tests

Some modern analysers will determine the percentage of

Midstream urine

GI tract visualisation (endoscopy or barium)

hypochromic red cells, which may be high before the anaemia

Consider specialist referral

develops (it is worth noting that a reduction in haemoglobin

concentration is a late feature of iron deficiency). The blood

Figure 1.2 Diagnosis and investigation of iron deficiency anaemia

film shows microcytic hypochromic red cells. Hypochromic

anaemia occurs in other disorders, such as anaemia of chronic

disorders and sideroblastic anaemias and in globin synthesis

Box 1.3 Investigations in iron deficiency anaemia

disorders, such as thalassaemia. To help to differentiate the

• Full clinical history and physical examination

type, further haematinic assays may be necessary. Difficulties in

• Full blood count and blood film examination

diagnosis arise when more than one type of anaemia is

• Haematinic assays (serum ferritin, vitamin B₁₂ folate)

present—for example, iron deficiency and folate deficiency in

• % hypochromic red cells and soluble transferrin receptor

malabsorption, in a population where thalassaemia is present,

assay (if available)

or in pregnancy, when the interpretation of red cell indices

• Urea and electrolytes, liver function tests

may be difficult.

• Fibreoptic and/or barium studies of gastrointestinal tract

Haematinic assays will demonstrate reduced serum ferritin

• Pelvic ultrasound (females, if indicated)

concentration in straightforward iron deficiency. As an acute

phase protein, however, the serum ferritin concentration may

be normal or even raised in inflammatory or malignant disease.

A prime example of this is found in rheumatoid disease, in

which active disease may result in a spuriously raised serum

ferritin concentration masking an underlying iron deficiency

caused by gastrointestinal bleeding after non-steroidal analgesic

treatment. There may also be confusion in liver disease as the

liver contains stores of ferritin that are released after

hepatocellular damage, leading to raised serum ferritin

concentrations. In cases where ferritin estimation is likely to be

misleading, the soluble transferrin receptor (sTfR) assay may aid

the diagnosis. Transferrin receptors are found on the surface of

red cells in greater numbers in iron deficiency; a proportion of

Figure 1.3 Blood film showing changes of iron deficiency anaemia

receptors are shed into the plasma and can be measured using

commercial kits. Unlike the serum ferritin, the sTfR does not

rise in inflammatory disorders, and hence can help differentiate

Table 1.2 Diagnosis of iron deficiency anaemia

between anaemia due to inflammation from iron deficiency.

Diagnostic bone marrow sampling is seldom performed in

Reduced haemoglobin

Men

135 g/l, women

115 g/l

simple iron deficiency, but if the diagnosis is in doubt a marrow

Reduced mean cell volume

76 fl

aspirate may be carried out to demonstrate absent bone

Reduced mean cell

29.5

2.5 pg

marrow stores.

haemoglobin

When iron deficiency has been diagnosed, the underlying

Reduced mean cell

325

25 g/l

haemoglobin concentration

cause should be investigated and treated. Often the history will

Blood film

Microcytic hypochromic red cells

indicate the likely source of bleeding—for example, menstrual

with pencil cells and target cells

blood loss or gastrointestinal bleeding. If there is no obvious

Reduced serum ferritin*

Men

g/l, women

cause, further investigation generally depends on the age and

(postmenopausal)

g/l

sex of the patient. In male patients and postmenopausal

(premenopausal)

g/l

women possible gastrointestinal blood loss is investigated by

Elevated % hypochromic red cells (

2%)

visualisation of the gastrointestinal tract (endoscopic or barium

Elevated soluble transferrin

studies). Faecal occult bloods are of no value in the

receptor level

investigation of iron deficiency.

*Check with local laboratory for reference ranges

Iron deficiency anaemia

Management

Table 1.3 Characteristics of anaemia associated with other

disorders

Effective management of iron deficiency relies on (a) the

appropriate management of the underlying cause (for

Iron

Chronic

Thalassaemia

Sideroblastic

example, gastrointestinal or menstrual blood loss) and (b) iron

deficiency disorders

trait ( or

)

anaemia

replacement therapy.

Degree of

Any

Seldom

Mild

Any

anaemia

9.0 g/dl

Oral iron replacement therapy with gradual replenishment

MCV

N orb

N orbora

of iron stores and restoration of haemoglobin is the preferred

Serum

N ora

treatment. Oral ferrous salts are the treatment of choice (ferric

ferritin

salts are less well absorbed) and usually take the form of

Soluble

ferrous sulphate 200 mg three times daily (providing

transferrin

65 mg

195 mg elemental iron/day). Alternative

receptor assay

preparations include ferrous gluconate and ferrous fumarate.

Marrow iron Absent

Present

All three compounds, however, are associated with a high

N norm

incidence of side effects, including nausea, constipation, and

diarrhoea. These side effects may be reduced by taking the

tablets after meals, but even milder symptoms account for poor

compliance with oral iron supplementation. Modified release

preparations have been developed to reduce side effects but in

practice prove expensive and often release the iron beyond the

sites of optimal absorption.

Effective iron replacement therapy should result in a rise in

haemoglobin concentration of around 1 g/l per day (about

20 g/l every three weeks), but this varies from patient to

patient. Once the haemoglobin concentration is within the

normal range, iron replacement should continue for three

months to replenish the iron stores.

Failure to respond to oral iron

Figure 1.4 Oral iron replacement therapy

therapy

The main reason for failure to respond to oral iron therapy is

poor compliance. However, if the losses (for example,

bleeding) exceed the amount of iron absorbed daily, the

haemoglobin concentration will not rise as expected; this will

also be the case in combined deficiency states.

Table 1.4 Elemental iron content of various oral iron

The presence of underlying inflammation or malignancy

preparations

may also lead to a poor response to therapy. Finally, an

Preparation

Amount (mg)

Ferrous iron (mg)

incorrect diagnosis of iron deficiency anaemia should be

Ferrous fumarate

200

considered in patients who fail to respond adequately to iron

Ferrous gluconate

300

replacement therapy.

Ferrous succinate

100

Ferrous sulphate

300

Intravenous and intramuscular iron preparations

Ferrous sulphate (dried)

200

Parenteral iron may be used when the patient cannot tolerate

oral supplements—for example, when patients have severe

gastrointestinal side effects or if the losses exceed the daily

amount that can be absorbed orally.

Iron sorbitol injection is a complex of iron, sorbitol and

citric acid. Treatment consists of a course of deep

intramuscular injections. The dosage varies from patient to

patient and depends on (a) the initial haemoglobin

Box 1.4 Intravenous iron preparations

concentration and (b) body weight. Generally, 10-20 deep

• Iron dextran no longer available (severe reactions)

intramuscular injections are given over two to three weeks.

• Iron-hydroxide sucrose is currently available in the UK

Apart from being painful, the injections also lead to skin

• Useful in selected cases

staining at the site of injection and arthralgia, and are best

• Must be given under close medical supervision and where

avoided. An intravenous preparation is available (Venofer^®) for

full resuscitation facilities are available

use in selected cases, and under strict medical supervision,

for example, on haematology day unit (risk of anaphylaxis or

other reactions).

Alternative treatments

Blood transfusion is not indicated unless the patient has

decompensated due to a drop in haemoglobin concentration

The rise in haemoglobin concentration is no faster with

and needs a more rapid rise in haemoglobin—for example, in

parenteral iron preparations than with oral iron therapy

cases of worsening angina or severe coexisting pulmonary

ABC of Clinical Haematology

disease. In cases of iron deficiency with serious ongoing acute

Further reading

bleeding, blood transfusion may be required.

• Baer AN, Dessypris EN, Krantz SB. The pathogenesis of anemia

in rheumatoid arthritis: a clinical and laboratory analysis. Semin

Prevention

Arthritis Rheum 1990;19(4):209-23.

When absorption from the diet is likely to be matched or

• Beguin Y. The soluble transferrin receptor: biological aspects

exceeded by losses, extra sources of iron should be

and clinical usefulness as quantitative measure of erythropoiesis.

considered—for example, prophylactic iron supplements in

Haematologica 1992;77(1):1-10.

• Cook JD, Skikne BS, Baynes RD. Iron deficiency: the global

pregnancy or after gastrectomy or encouragement of breast

perspective. Adv Exp Med Biol 1994;356:219-28.

feeding or use of formula milk during the first year of life

• DeMaeyer E, Adiels-Tegman M. The prevalence of anaemia in

(rather than cows’ milk, which is a poor source of iron).

the world. World Health Stat Q 1985;38(3):302-16.

• Ferguson BJ, Skikne BS, Simpson KM, Baynes RD, Cook JD.

Serum transferrin receptor distinguishes the anemia of chronic

disease from iron deficiency anemia. J Lab Clin Med

1992;119(4):385-90.

• Finch CA, Huebers HA. Iron metabolism. Clin Physiol Biochem

1986;4(1):5-10.

• McIntyre AS, Long RG. Prospective survey of investigations in

outpatients referred with iron deficiency anaemia. Gut

1993;34(8):1102-7.

• Provan D. Mechanisms and management of iron deficiency

anaemia. Br J Haematol 1999;105 Suppl 1:19-26.

• Punnonen K, Irjala K, Rajamaki A. Serum transferrin receptor

and its ratio to serum ferritin in the diagnosis of iron deficiency.

Blood 1997;89(3):1052-7.

• Rockey DC, Cello JP. Evaluation of the gastrointestinal tract in

patients with iron-deficiency anemia. N Engl J Med

1993;329(23):1691-5.

Drs AG Smith and A Amos provided the photographic material and

• Windsor CW, Collis JL. Anaemia and hiatus hernia: experience

Dr A Odurny provided the radiograph. The source of the detail in

in 450 patients. Thorax 1967;22(1):73-8.

the table is the British National Formulary, No 32(Sep), 1995.

Macrocytic anaemias

Victor Hoffbrand, Drew Provan

Macrocytosis is a rise in the mean cell volume of the red cells

Megaloblastic bone marrow is exemplified by developing

above the normal range (in adults 80-95 fl (femtolitres)). It is

red blood cells that are larger than normal, with nuclei

detected with a blood count, in which the mean cell volume, as

more immature than their cytoplasm. The underlying

well as other red cell indices, is measured. The mean cell

mechanism is defective DNA synthesis

volume is lower in children than in adults, with a normal mean

of 70 fl at age 1 year, rising by about 1 fl each year until it

reaches adult volumes at puberty.

The causes of macrocytosis fall into two groups:

Box 2.1 Causes of megaloblastic anaemia

(a) deficiency of vitamin B₁₂ (cobalamin) or folate (or rarely

Diet

abnormalities of their metabolism) in which the bone marrow

• Vitamin B₁₂ deficiency: veganism, poor quality diet

is megaloblastic, and (b) other causes, in which the bone

• Folate deficiency: poor quality diet, old age, poverty,

marrow is usually normoblastic. In this chapter the two groups

synthetic diet without added folic acid, goats’ milk

are considered separately. The reader is then taken through the

Malabsorption

steps to diagnose the cause of macrocytosis, and subsequently

• Gastric causes of vitamin B₁₂ deficiency: pernicious anaemia,

to manage it.

congenital intrinsic factor deficiency or abnormality

gastrectomy

•

Intestinal causes of vitamin B₁₂ deficiency: stagnant loop,

congenital selective malabsorption, ileal resection, Crohn’s

Deficiency of vitamin B₁₂ or folate

disease

• Intestinal causes of folate deficiency: gluten-induced

Vitamin B₁₂ deficiency

enteropathy, tropical sprue, jejunal resection

The body’s requirement for vitamin B₁₂ is about 1

g daily. This

Increased cell turnover

is amply supplied by a normal Western diet (vitamin B₁₂

• Folate deficiency: pregnancy, prematurity, chronic

content 10-30

g daily) but not by a strict vegan diet, which

haemolytic anaemia (such as sickle cell anaemia), extensive

excludes all animal produce (including milk, eggs, and

inflammatory and malignant diseases

cheese). Absorption of vitamin B₁₂ is through the ileum,

Renal loss

facilitated by intrinsic factor, which is secreted by the parietal

• Folate deficiency: congestive cardiac failure, dialysis

cells of the stomach. Absorption is limited to 2-3

g daily.

Drugs

In Britain, vitamin B₁₂ deficiency is usually due to

• Folate deficiency: anticonvulsants, sulphasalazine

pernicious anaemia, which now accounts for up to 80% of all

Defects of vitamin B₁₂ metabolism—eg transcobalamin II

cases of megaloblastic anaemia. The incidence of the disease is

deficiency, nitrous oxide anaesthesia—or of folate metabolism

1:10 000 in northern Europe, and the disease occurs in all

(such as methotrexate treatment), or rare inherited defects of

DNA synthesis may all cause megaloblastic anaemia

races. The underlying mechanism is an autoimmune gastritis

that results in achlorhydria and the absence of intrinsic factor.

The incidence of pernicious anaemia peaks at age 60; the

condition has a female:male incidence of 1.6:1.0 and is more

common in those with early greying, blue eyes, and blood

group A, and in those with a family history of the disease or of

diseases that may be associated with it—for example, vitiligo,

myxoedema, Hashimoto’s disease, Addison’s disease of the

adrenal gland, and hypoparathyroidism.

Other causes of vitamin B₁₂ deficiency are infrequent in

Britain. Veganism is an unusual cause of severe deficiency, as

most vegetarians and vegans include some vitamin B₁₂ in their

diet. Moreover, unlike in pernicious anaemia, the

enterohepatic circulation for vitamin B₁₂ is intact in vegans, so

vitamin B₁₂ stores are conserved. Gastric resection and

intestinal causes of malabsorption of vitamin B₁₂—for example,

ileal resection or the intestinal stagnant loop syndrome—are

less common now that abdominal tuberculosis is infrequent

and H₂-antagonists have been introduced for treating peptic

ulceration, thus reducing the need for gastrectomy.

Folate deficiency

The daily requirement for folate is 100-200

g, and a normal

mixed diet contains about 200-300

g. Natural folates are

Figure 2.1

Patient with vitiligo on neck and back

largely in the polyglutamate form, and these are absorbed

through the upper small intestine after deconjugation and

conversion to the monoglutamate 5-methyl tetrahydrofolate.

Body stores are sufficient for only about four months.

Folate deficiency may arise because of inadequate dietary

ABC of Clinical Haematology

intake, malabsorption (especially gluten-induced enteropathy),

or excessive use as proliferating cells degrade folate. Deficiency

in pregnancy may be due partly to inadequate diet, partly to

transfer of folate to the fetus, and partly to increased folate

degradation.

Consequences of vitamin B₁₂ or folate deficiencies

Megaloblastic anaemia—Clinical features include pallor and

jaundice. The onset is gradual, and a severely anaemic patient

may present in congestive heart failure or only when an

infection supervenes. The blood film shows oval macrocytes

and hypersegmented neutrophil nuclei (with six or more

lobes). In severe cases, the white cell count and platelet count

also fall (pancytopenia). The bone marrow shows characteristic

megaloblastic erythroblasts and giant metamyelocytes

(granulocyte precursors). Biochemically, there is an increase in

plasma of unconjugated bilirubin and serum lactic

dehydrogenase, with, in severe cases, an absence of

haptoglobins and presence in urine of haemosiderin. These

changes, including jaundice, are due to increased destruction

of red cell precursors in the marrow (ineffective

erythropoiesis).

Figure 2.2

Patient with celiac disease: underweight and low stature

Vitamin B₁₂ neuropathy—A minority of patients with

vitamin B₁₂ deficiency develop a neuropathy due to

symmetrical damage to the peripheral nerves and posterior

and lateral columns of the spinal cord, the legs being more

affected than the arms. Psychiatric abnormalities and visual

disturbance may also occur. Men are more commonly affected

than women. The neuropathy may occur in the absence of

anaemia. Psychiatric changes and at most a mild peripheral

neuropathy may be ascribed to folate deficiency.

Neural tube defects—Folic acid supplements in pregnancy

have been shown to reduce the incidence of neural tube

defects (spina bifida, encephalocoele, and anencephaly) in the

fetus and may also reduce the incidence of cleft palate and

hare lip. No clear relation exists between the incidence of these

defects and folate deficiency in the mother, although the lower

Figure 2.3

Blood film in vitamin B₁₂ deficiency showing macrocytic red

the maternal red cell folate (and serum vitamin B₁₂)

cells and a hypersegmented neutrophil

concentrations even within the normal range, the more likely

neural tube defects are to occur in the fetus. An underlying

mechanism in a minority of cases is a genetic defect in folate

metabolism, a mutation in the enzyme 5, 10 methylenetetra

hydrofolate reductase.

Gonadal dysfunction—Deficiency of either vitamin B₁₂ or

folate may cause sterility, which is reversible with appropriate

vitamin supplementation.

Epithelial cell changes—Glossitis and other epithelial surfaces

may show cytological abnormalities.

Cardiovascular disease—Raised serum homocysteine

concentrations have been associated with arterial obstruction

(myocardial infarct, peripheral vascular disease or stroke) and

venous thrombosis. Trials are under way to determine whether

folic acid supplementation reduces the incidence of these

vascular diseases.

Other causes of macrocytosis

The most common cause of macrocytosis in Britain is alcohol.

Fairly small quantities of alcohol—for example, two gin and

tonics or half a bottle of wine a day—especially in women, may

cause a rise of mean cell volume to

100 fl, typically without

Figure 2.4 Glossitis due to vitamin B₁₂ deficiency

anaemia or any detectable change in liver function.

The mechanism for the rise in mean cell volume is

uncertain. In liver disease the volume may rise due to excessive

lipid deposition on red cell membranes, and the rise is

particularly pronounced in liver disease caused by alcohol.

Macrocytic anaemias

A modest rise in mean cell volume is found in severe thyroid

Box 2.2 Other causes of macrocytosis*

deficiency.

• Alcohol

• Myelodysplasia

In other causes of macrocytosis, other haematological

• Liver disease

• Cytotoxic drugs

abnormalities are usually present—in myelodysplasia

• Hypothyroidism

• Paraproteinaemia (such as myeloma)

(a frequent cause of macrocytosis in elderly people) there are

• Reticulocytosis

• Pregnancy

usually quantitative or qualitative changes in the white cells and

• Aplastic anaemia

• Neonatal period

platelets in the blood. In aplastic anaemia, pancytopenia is

• Red cell aplasia

present; pure red cell aplasia may also cause macrocytosis.

*These are usually associated with a normoblastic marrow

Changes in plasma proteins—presence of a paraprotein (as in

myeloma)—may cause a rise in mean cell volume without

macrocytes being present in the blood film. Physiological

causes of macrocytosis are pregnancy and the neonatal period.

Drugs that affect DNA synthesis—for example, hydroxyurea

and azathioprine—can cause macrocytosis with or without

megaloblastic changes. Finally, a rare, benign familial type of

macrocytosis has been described.

Diagnosis

Biochemical assays

The most widely used screening tests for the deficiencies are

the serum vitamin B₁₂ and folate assays. A low serum

concentration implies deficiency, but a subnormal serum

concentration may occur in the absence of pronounced body

deficiency—for example, in pregnancy (vitamin B₁₂) and with

recent poor dietary intake (folate).

Figure 2.5 Bone marrow aspirate in myelodysplasia showing

characteristic dysplastic neutrophils with bilobed nuclei

Red cell folate can also be used to screen for folate

deficiency; a low concentration usually implies appreciable

depletion of body folate, but the concentration also falls in

Box 2.3 Investigations that may be needed in patients

severe vitamin B₁₂ deficiency, so it is more difficult to interpret

with macrocytosis

the significance of a low red cell than serum folate

• Serum vitamin B₁₂ assay

concentration in patients with megaloblastic anaemia.

• Serum and red cell folate assays

Moreover, if the patient has received a recent blood transfusion

• Liver and thyroid function

the red cell folate concentration will partly reflect the folate

• Reticulocyte count

• Serum protein electrophoresis

concentration of the transfused red cells.

For vitamin B₁₂ deficiency: serum parietal cell and intrinsic

•

absorption with

factor antibodies, radioactive vitamin B₁₂

Specialist investigations

and without intrinsic factor (Schilling test), possibly serum

Assays of serum homocysteine (raised in vitamin B₁₂ or folate

gastrin concentration

deficiency) or methylmalonic acid (raised in vitamin B₁₂

• For folate deficiency: antigliadin, anti-endomysial and

deficiency) are used in some specialised laboratories. Serum

antireticulin antibodies

• Consider bone marrow examination for megaloblastic

homocysteine levels are also raised in renal failure, with certain

changes suggestive of vitamin B₁₂ or folate deficiency, or

drugs, e.g. corticosteroids, and increase with age and smoking.

alternative diagnoses—eg myelodysplasia, aplastic anaemia,

myeloma

Autoantibodies

• Endoscopy—gastric biopsy (vitamin B₁₂ deficiency);

For patients with vitamin B₁₂ or folate deficiency it is important

duodenal biopsy (folate deficiency)

to establish the underlying cause. In pernicious anaemia,

• Serum antigliadin and anti-endomysial antibodies

intrinsic factor antibodies are present in plasma in 50% of

patients and in parietal cell antibodies in 90%. Antigliadin,

anti-endomysial and antireticulin antibodies are usually positive

in gluten-induced enteropathy.

Other investigations

A bone marrow examination is usually performed to confirm

megaloblastic anaemia. It is also required for the diagnosis of

myelodysplasia, aplastic anaemia, myeloma, or other marrow

disorders associated with macrocytosis.

Radioactive vitamin B₁₂ absorption studies—for example,

Schilling test—show impaired absorption of the vitamin in

pernicious anaemia; this can be corrected by giving intrinsic

factor. In patients with an intestinal lesion, however, absorption

of vitamin B₁₂ cannot be corrected with intrinsic factor. Human

intrinsic factor is no longer licensed for this test because of

concern about transmission of prion disease.

Figure 2.6 Bone marrow appearances in megaloblastic anaemia:

Endoscopy should be performed to confirm atrophic

developing red cells are larger than normal, with nuclei that are

gastritis and exclude gastric carcinoma or gastric polyps, which

immature relative to their cytoplasm (nuclear:cytoplasmic asynchrony)

ABC of Clinical Haematology

are two to three times more common in patients with

Table 2.1 Results of absorption tests of radioactive

pernicious anaemia than in age and sex matched controls.

vitamin B₁₂

If folate deficiency is diagnosed, it is important to assess

dietary folate intake and to exclude gluten induced

Dose of vitamin B₁₂

enteropathy by tests for serum antigliadin and anti-endomysial

Dose of vitamin B₁₂

given with intrinsic

given alone

factor^†

antibodies, endoscopy and duodenal biopsy. The deficiency is

Vegan

Normal

common in patients with diseases of increased cell turnover

Pernicious anaemia

Low

Normal

who also have a poor diet.

or gastrectomy

lleal resection

Low

Intestinal blind-loop

Low^*

Treatment

syndrome

Vitamin B₁₂ deficiency is treated initially by giving the patient

^*Corrected by antibodies.

six injections of hydroxo-cobalamin 1 mg at intervals of about

^†Human intrinsic factor no longer licensed for this test because of

three to four days, followed by four such injections a year for

concern about prion transmission

life. For patients undergoing total gastrectomy or ileal resection

it is sensible to start the maintenance injections from the time

of operation. For vegans, less frequent injections—for example,

one or two a year—may be sufficient, and the patient should be

Box 2.4 Preventing folate deficiency in pregnancy

advised to eat foods to which vitamin B₁₂ has been added, such

as certain fortified breads or other foods.

• As prophylaxis against folate deficiency in pregnancy, daily

doses of folic acid 400

g are usual

Folate deficiency is treated with folic acid, usually 5 mg daily

• Larger doses are not recommended as they could mask

orally for four months, which is continued only if the

megaloblastic anaemia due to vitamin B₁₂ deficiency and

underlying cause cannot be corrected. As prophylaxis against

thus allow B₁₂ neuropathy to develop

folate deficiency in patients with a severe haemolytic anaemia—

• As neural tube defects occur by the 28th day of pregnancy, it

such as sickle cell anaemia—5 mg folic acid once weekly is

is advisable for a woman’s daily folate intake to be increased

probably sufficient. Vitamin B₁₂ deficiency must be excluded in

by 400

g/day at the time of conception

• The US Food and Drugs Administration announced in 1996

all patients starting folic acid treatment at these doses as such

that specified grain products (including most enriched

treatment may correct the anaemia in vitamin B₁₂ deficiency

breads, flours, cornmeal, rice, noodles, and macaroni) will

but allow neurological disease to develop.

be required to be fortified with folic acid to levels ranging

from 0.43 mg to 1.5 mg per pound (453 g) of product.

Fortification of flour with folic acid is currently under

discussion in the UK

Further reading

• For mothers who have already had an infant with a neural

• Carmel R. Current concepts in cobalamin deficiency. Annu Rev

tube defect, larger doses of folic acid—eg 5 mg daily—are

Med 2000;51:357-75.

recommended before and during subsequent pregnancy

• Clarke R, Smith AD, Jobst KA, Refsum H, Sutton L, Ueland PM.

Folate, vitamin B₁₂, and serum total homocysteine levels in

confirmed Alzheimer disease. Arch Neurol 1998;55(11):1449-55.

• Haynes WG. Homocysteine and atherosclerosis: potential

mechanisms and clinical implications. Proc R Coll Phys Edinb

2000;30:114-22.

• Jacques PF, Selhub J, Bostom AG, Wilson PW, Rosenberg IH. The

effect of folic acid fortification on plasma folate and total

homocysteine concentrations. N Engl J Med 1999;340(19):1449-54.

• Lindenbaum J, Allen RH. Clinical spectrum and diagnosis of

folate deficiency. In: Bailey LB. Folate in health and disease. New

York: Marcel Dekker 1995;pp43-73.

• Mills JL. Fortification of foods with folic acid—how much is

enough? N Engl J Med 2000;342(19):1442-5.

• Perry DJ. Hyperhomocysteinaemia. Baillieres Best Pract Res Clin

Haematol 1999;12(3):451-77.

The illustration of the bone marrow (Figure 2.6)

• Wickramasinghe SN. Morphology, biology and biochemistry of

is reproduced with permission from Clinical haematology

cobalamin- and folate-deficient bone marrow cells. Baillieres Clin

(AV Hoffbrand, J Pettit), 3rd ed, St Louis:

Haematol 1995;8(3):441-59.

CV Mosby, 2000.

The hereditary anaemias

David J Weatherall

Hereditary anaemias include disorders of the structure or

Chromosome 16

Chromosome 11

synthesis of haemoglobin; deficiencies of enzymes that provide

the red cell with energy or protect it from chemical damage;

α α

and abnormalities of the proteins of the red cell’s membrane.

Inherited diseases of haemoglobin—haemoglobinopathies—are

by far the most important.

The structure of human haemoglobin (Hb) changes during

development. By the 12th week embryonic haemoglobin is

replaced by fetal haemoglobin (Hb F), which is slowly replaced

after birth by the adult haemoglobins, Hb A and Hb A₂. Each

type of haemoglobin consists of two different pairs of peptide

ζ₂ε₂

α₂γ₂

α₂β₂

α₂δ₂

Hb Gower 1

HbF

HbA

HbA₂

chains; Hb A has the structure

(namely, two chains plus

Embryo

Fetus

Adult

two chains), Hb A₂ has the structure of

2, and Hb F,

The haemoglobinopathies consist of structural

Figure 3.1 Simplified representation of the genetic control of human

haemoglobin variants (the most important of which are the

haemoglobin. Because chains are shared by both fetal and adult Hb,

sickling disorders) and thalassaemias (hereditary defects of the

mutations of the globin genes affect Hb production in both fetal and

adult life; diseases that are due to defective globin production are only

synthesis of either the or globin chains).

manifest after birth when Hb A replace Hb F

The sickling disorders

Classification and inheritance

Box 3.1 Sickling syndromes

The common sickling disorders consist of the homozygous state

• Hb SS (sickle cell anaemia)

for the sickle cell gene—that is, sickle cell anaemia (Hb SS)—

• Hb SC disease

and the compound heterozygous state for the sickle cell gene

• Hb S/ thalassaemia

and that for either Hb C (another chain variant) or

• Hb S/ thalassaemia

thalassaemia (termed Hb SC disease or sickle cell

• Hb SD disease

thalassaemia). The sickle cell mutation results in a single

amino acid substitution in the globin chain; heterozygotes

have one normal (^A) and one affected chain (^S) gene and

produce about 60% Hb A and 40% Hb S; homozygotes

produce mainly Hb S with small amounts of Hb F. Compound

heterozygotes for Hb S and Hb C produce almost equal

Box 3.2 Sickle cell trait (Hb A and Hb S)

amounts of each variant, whereas those who inherit the sickle

• Less than half the Hb in each red cell is Hb S

cell gene from one parent and thalassaemia from the other

• Occasional renal papillary necrosis

• Inability to concentrate the urine (older individuals)

make predominantly sickle haemoglobin.

Red cells do not sickle unless oxygen saturations

40%

•

(rarely reached in venous blood)

Pathophysiology

• Painful crises and splenic infarction have been reported in

The amino acid substitution in the globin chain causes red cell

severe hypoxia—such as unpressurised aircraft, anaesthesia

sickling during deoxygenation, leading to increased rigidity and

Sickling is more severe where Hb S is present with another

aggregation in the microcirculation. These changes are reflected

globin chain abnormality—such as Hb S and Hb C (Hb SC)

by a haemolytic anaemia and episodes of tissue infarction.

or Hb S and Hb D (Hb SD)

Geographical distribution

The sickle cell gene is spread widely throughout Africa and in

countries with African immigrant populations; some

Mediterranean countries; the Middle East; and parts of India.

Box 3.3 Sickle cell anaemia (homozygous Hb S)

Screening should not be restricted to people of African origin.

• Anaemia (Hb 60-100 g/l): symptoms milder than expected

as Hb S has reduced oxygen affinity (that is, gives up oxygen

Clinical features

to tissues more easily)

Sickle cell carriers are not anaemic and have no clinical

• Sickled cells may be present in blood film: sickling occurs at

oxygen tensions found in venous blood; cyclical sickling

abnormalities. Patients with sickle cell anaemia have

episodes

a haemolytic anaemia, with haemoglobin concentration

• Reticulocytes: raised to 10-20%

60-100 g/l and a high reticulocyte count; the blood film shows

• Red cells contain

80% Hb S (rest is maily fetal Hb)

polychromasia and sickled erythrocytes.

• Variable haemolysis

Patients adapt well to their anaemia, and it is the vascular

• Hand and foot syndrome (dactylitis)

occlusive or sequestration episodes (“crises”) that pose the

• Intermittent episodes, or crises, characterised by bone pain,

worsening anaemia, or pulmonary or neurological disease

main threat. Crises take several forms. The commonest, called

• Chronic leg ulcers

the painful crisis, is associated with widespread bone pain and

• Gall stones

is usually self-limiting. More serious and life threatening crises

ABC of Clinical Haematology

include the sequestration of red cells into the lung or spleen,

Box 3.4 Complications of sickle cell disease

strokes, or red cell aplasia associated with parvovirus infections.

Hand and foot syndrome: seen in infancy; painful swelling

•

of digits

Diagnosis

• Painful crises: later in life; generalised bone pain;

Sickle cell anaemia should be suspected in any patient of an

precipitated by cold, dehydration but often no cause found;

appropriate racial group with a haemolytic anaemia. It can be

self limiting over a few days

confirmed by a sickle cell test, although this does not

• Aplastic crisis: marrow temporarily hypoplastic; may follow

distinguish between heterozygotes and homozygotes.

parvovirus infection; profound anaemia; reduced

reticulocyte count

A definitive diagnosis requires haemoglobin electrophoresis

• Splenic sequestration crisis: common in infancy; progressive

and the demonstration of the sickle cell trait in both parents.

anaemia; enlargement of spleen

• Hepatic sequestration crisis: similar to splenic crisis but with

Prevention and treatment

sequestration of red cells in liver

Pregnant women in at-risk racial groups should be screened in

• Lung or brain syndromes: sickling of red cells in pulmonary

early pregnancy and, if the woman and her partner are carriers,

or cerebral circulation and endothelial damage to cerebral

should be offered either prenatal or neonatal diagnosis. As soon

vessels in cerebral circulation

• Infections: particularly Streptococcus pneumoniae and

as the diagnosis is established babies should receive penicillin

Haemophilus influenzae

daily and be immunised against Streptococcus pneumoniae,

• Gall stones

Haemophilus influenzae type b, and Neisseria meningitidis. Parents

• Progressive renal failure

should be warned to seek medical advice on any suspicion of

• Chronic leg ulcers

infection. Painful crises should be managed with adequate

• Recurrent priapism

analgesics, hydration, and oxygen. The patient should be

• Aseptic necrosis of humoral/femoral head

• Chronic osteomyelitis: sometimes due to Salmonella typhi

observed carefully for a source of infection and a drop in

haemoglobin concentration. Pulmonary sequestration crises

require urgent exchange transfusion together with oxygen

therapy. Strokes should be treated with a transfusion; there is

good evidence now that they can be prevented by regular

surveillance of cerebral blood flow by Doppler examination and

prophylactic transfusion. There is also good evidence that the

frequency of painful crises can be reduced by maintaining

Box 3.5 Treatment of major complications of sickle cell

patients on hydroxyurea, although because of the uncertainty

disease

about the long term effects of this form of therapy, it should be

• Hand and foot syndrome: hydration; paracetamol

restricted to adults or, if it is used in children, this should be

• Painful crises: hydration; analgesia (including graded

only for a short period. Aplastic crises require urgent blood

intravenous analgesics); oxygen (check arterial blood gases);

transfusion. Splenic sequestration crises require transfusion and,

blood cultures; antibiotics

• Pulmonary infiltrates: especially with deterioration in

because they may recur, splenectomy is advised.

arterial gases, falling platelet count and/or haemoglobin

concentration suggesting lung syndrome requires urgent

Sickling variants

exchange blood transfusion to reduce Hb S level together

Hb SC disease is characterised by a mild anaemia and fewer

with oxygenation

crises. Important microvascular complications, however, include

• Splenic sequestration crisis: transfusion; splenectomy to

retinal damage and blindness, aseptic necrosis of the femoral

prevent recurrence

• Neurological symptoms: immediate exchange transfusion

heads, and recurrent haematuria. The disease is occasionally

followed by long term transfusion

complicated by pulmonary embolic disease, particularly during

• Prevention of crises: ongoing trials of cytotoxic agent

and after pregnancy; these episodes should be treated by

hydroxyurea show that it raises Hb F level and ameliorates

immediate exchange transfusion. Patients with Hb SC should

frequency and severity of crises; long term effects unknown

have annual ophthalmological surveillance; the retinal vessel

proliferation can be controlled with laser treatment.

Figure 3.3 Haemoglobin electrophoresis showing (1) normal,

Figure 3.2 Peripheral blood film from patient with sickle cell anaemia

(2) newborn, (3) Hb C trait (A-C), (4) Hb SC disease (SC), (5) sickle

showing sickled erythrocytes

cell disease (SS), (6) sickle cell trait (A-S), (7) newborn, (8) normal

The hereditary anaemias

The management of the symptomatic forms of sickle cell

thalassaemia is similar to that of sickle cell anaemia.

The thalassaemias

Classification

α and β Thalassaemia

The thalassaemias are classified as or thalassaemias,

depending on which pair of globin chains is synthesised

inefficiently. Rarer forms affect both and chain

production— thalassaemias.

Distribution

Figure 3.4 Distribution of the thalassaemias (red area)

The disease is broadly distributed throughout parts of Africa,

the Mediterranean region, the Middle East, the Indian

α^οThalassaemia

α⁺Thalassaemia

subcontinent, and South East Asia, and it occurs sporadically in

all racial groups. Like sickle cell anaemia, it is thought to be

common because carriers have been protected against malaria.

Inheritance

The thalassaemias result from over 150 different mutations of

the globin genes, which reduce the output of globin

chains, either completely ( thalassaemia) or partially (

thalassaemia). They are inherited like sickle cell anaemia;

carrier parents have a one in four chance of having a

homozygous child. The genetics of the thalassaemias is more

Normal

α^οThalassaemia

α⁺Thalassaemia

HbH disease

complicated because normal people have two globin genes

Figure 3.5 Inheritance of Hb disease (open boxes represent normal

on each of their chromosomes 16. If both are lost (

globin genes and red boxes, deleted globin genes)

thalassaemia) no globin chains are made, whereas if only one

of the pair is lost (

thalassaemia) the output of globin

Box 3.6

Thalassaemia trait (heterozygous carrier)

chains is reduced. Impaired globin production leads to

• Mild hypochromic microcytic anaemia

excess or chains that form unstable and physiologically

Haemoglobin 90-110 g/l

useless tetramers,

(Hb Bart’s) and

(Hb H). The

Mean cell volume 50-70 fl

homozygous state for thalassaemia results in the Hb Bart’s

Mean corpuscular haemoglobin 20-22 pg

hydrops syndrome, whereas the inheritance of and

• No clinical features, patients asymptomatic

thalassaemia produces Hb H disease.

• Often diagnosed on routine blood count

• Raised Hb A₂ level

The thalassaemias

Heterozygotes for thalassaemia are asymptomatic, have

Box 3.7

Thalassaemia major (homozygous

hypochromic microcytic red cells with a low mean cell

thalassaemia)

haemoglobin and mean cell volume, and have a mean Hb A₂

• Severe anaemia

level of about twice normal. Homozygotes, or those who have

• Blood film

inherited a different thalassaemia gene from both parents,

Pronounced variation in red cell size and shape

usually develop severe anaemia in the first year of life. This

Pale (hypochromic) red cells

results from a deficiency of globin chains; excess chains

Target cells

precipitate in the red cell precursors leading to their damage,

Basophilic stippling

Nucleated red cells

either in the bone marrow or the peripheral blood.

Moderately raised reticulocyte count

Hypertrophy of the ineffective bone marrow leads to skeletal

• Infants are well at birth but develop anaemia in first few

changes, and there is variable hepatosplenomegaly. The Hb F

months of life when switch occurs from to globin chains

level is always raised. If these children are transfused, the

• Progressive splenomegaly; iron loading; proneness to infection

marrow is “switched off”, and growth and development may be

normal. However, they accumulate iron and may die later from

damage to the myocardium, pancreas, or liver. They are also

prone to infection and folic acid deficiency. Milder forms of

thalassaemia (thalassaemia intermedia), although not

transfusion dependent, are sometimes associated with similar

bone changes, anaemia, leg ulcers, and delayed development.

The thalassaemias

The Hb Bart’s hydrops fetalis syndrome is characterised by the

stillbirth of a severely oedematous (hydropic) fetus in the

second half of pregnancy. Hb H disease is associated with a

moderately severe haemolytic anaemia. The carrier states for

thalassaemia or the homozygous state for

thalassaemia result

in a mild hypochromic anaemia with normal Hb A₂ levels. They

Figure 3.6 Peripheral blood film in homozygous thalassaemia showing

can only be distinguished with certainty by DNA analysis in a

pronounced hypochromia and anisocytosis with nucleated red blood cells

ABC of Clinical Haematology

Box 3.8 The thalassaemias

Normal

gene deleted

α2γ2

α2β2

•

Asymptomatic

HbF

HbA

• Minority show reduced mean cell volume and mean

corpuscular haemoglobin

α Thalassaemia

/- or

/- - 2

genes deleted

•

Haemoglobin is normal or slightly reduced

α2

γ2

α2

β2

• Reduced mean cell volume and mean corpuscular

haemoglobin

Excess

•

No symptoms

- -/ -

genes deleted, Hb H disease

•

Chronic haemolytic anaemia

• Reduced chain production with formation of

4 tetramers

(

4 is termed Hb H)

γ4

β4

•

Hb H is unstable and precipitates in older red cells

Hb Bart's

HbH

• Haemoglobin is 70-110 g/l, though may be lower

•

Reduced mean cell volume and mean corpuscular

haemoglobin

High oxygen affinity, anoxia unstable, haemolysis

•

Clinical features: jaundice, hepatosplenomegaly, leg ulcers,

gall stones, folate deficiency

Figure 3.7 Pathophysiology of thalassaemia

- -/- - 4

genes deleted, Hb Bart’s hydrops

•

No chains produced

• Mainly

, forms tetramers (

Hb Bart’s)

specialised laboratory. In addition to the distribution

•

Intrauterine death or stillborn at 25-40 weeks or dies soon

mentioned above, thalassaemia is also seen in European

after birth

populations in association with mental retardation; the

/ represents 2

globin genes inherited from each parent

molecular pathology is quite different to the common inherited

Changes due to thalassaemia are present from birth unlike

forms of the condition. There are two major forms of

in thalassaemia

thalassaemia associated with mental retardation (ATR); one

is encoded on chromosome 16 (ATR-16) and the other on the

X chromosome (ATRX). ATR-16 is usually associated with mild

mental retardation and is due to loss of the globin genes

together with other genetic material from the end of the short

arm of chromosome 16. ATRX is associated with more severe

mental retardation and a variety of skeletal deformities and is

encoded by a gene on the X chromosome which is expressed

widely in different tissues during different stages of

development. These conditions should be suspected in any

Box 3.9 Women with thalassaemia

infant or child with retarded development who has the

• Women with the haematological features of thalassaemia

haematological picture of a mild thalassaemia trait.

trait with normal Hb A₂ levels should be referred to a centre

able to identify the different forms of thalassaemia

• Those with thalassaemia trait—if their partners are

Prevention and treatment

similarly affected—should be referred for prenatal diagnosis

As thalassaemia is easily identified in heterozygotes, pregnant

• This is because the haemoglobin Bart’s hydrops syndrome is

women of appropriate racial groups should be screened; if a

associated with an increased risk of toxaemia of pregnancy

woman is found to be a carrier, her partner should be tested

and postpartum bleeding due to a hypertrophied placenta

and the couple counselled. Prenatal diagnosis by chorionic

villus sampling can be carried out between the 9th and 13th

weeks of pregnancy. If diagnosis is established, the patients

should be treated by regular blood transfusion with surveillance

for hepatitis C and related infections.

To prevent iron overload, overnight infusions of

desferrioxamine together with vitamin C should be started, and

the patient’s serum ferritin, or better, hepatic iron

concentrations, should be monitored; complications of

desferrioxamine include infections with Yersinia spp, retinal

and acoustic nerve damage, and reduction in growth associated

with calcification of the vertebral discs. The place of the oral

chelating agent deferiprone is still under evaluation. It is now

clear that it does not maintain iron balance in approximately

50% of patients and its long term toxicity remains to be

evaluated by adequate controlled trials. It is known to cause

neutropenia and transient arthritis. Current studies are

directed at assessing its value in combination with

desferrioxamine. Bone marrow transplantation—if appropriate

HLA-DR matched siblings are available—may carry a good

prognosis if carried out early in life. Treatment with agents

designed to raise the production of Hb F is still at the

Figure 3.8 Liver biopsy from patient with thalassaemia showing

experimental stage.

pronounced iron accumulation

The hereditary anaemias

In thalassaemia and Hb H disease progressive

splenomegaly or increasing blood requirements, or both,

indicate that splenectomy may be beneficial. Patients who

undergo splenectomy should be vaccinated against

S pneumoniae, H influenzae, and N meningitidis preoperatively

and should receive a maintenance dose of oral penicillin

indefinitely.

Box 3.10 Drugs causing haemolysis in patients with

G6PD deficiency

Red cell enzyme defects

Antimalarials

Primiquine

Red cells have two main metabolic pathways, one burning

Pamaquine

glucose anaerobically to produce energy, the other generating

Analgesics*

reduced glutathione to protect against injurious oxidants. Many

Phenacetin

Acetyl salicylic acid

inherited enzyme defects have been described. Some of those

Others

of the energy pathway—for example, pyruvate kinase

Sulphonamides

deficiency—cause haemolytic anaemia; any child with this kind

Nalidixic acid

of anaemia from birth should be referred to a centre capable

Dapsone

of analysing the major red cell enzymes.

*Probably only at high doses

Glucose-6-phosphate dehydrogenase deficiency (G6PD)

involves the protective pathway. It affects millions of people

worldwide, mainly the same racial groups as are affected by the

thalassaemias. Glucose-6-phosphate dehydrogenase deficiency is

sex linked and affects males predominantly. It causes neonatal

jaundice, sensitivity to fava beans (broad beans), and

haemolytic responses to oxidant drugs.

Red cell membrane defects

Further reading

The red cell membrane is a complex sandwich of proteins that

• Ballas SK. Sickle cell disease: clinical management. Clin Haematol

are required to maintain the integrity of the cell. There are

1998;11:185-214.

many inherited defects of the membrane proteins, some of

• Luzzatto L, Gordon-Smith EC. Hereditary haemolytic anaemia.

which cause haemolytic anaemia. Hereditary spherocytosis is

In: Hoffbrand AV, Lewis SM, Tuddenham GD, eds. Postgraduate

due to a structural change that makes the cells more leaky. It is

haematology. Oxford: Butterworth-Heinemann, 1999, pp144-163.

particularly important to identify this disease because it can be

• Steinberg MH. Pathophysiology of sickle cell disease. Clin

“cured” by splenectomy. There are many rare inherited varieties

Haematol 1998;11:163-84.

• Steinberg MH, Forget BG, Higgs DR, Nagel RL. Disorders of

of elliptical or oval red cells, some associated with chronic

haemoglobin. Cambridge: Cambridge University Press, 2001.

haemolysis and response to splenectomy. A child with a chronic

• Weatherall DJ. The thalassemias. In: Stamatayonnopoulos G,

haemolytic anaemia with abnormally shaped red cells should

Perlmutter RM, Marjerus PW, Varmus H, eds. Molecular basis of

always be referred for expert advice.

blood diseases, 3rd edn. Philadelphia: WB Saunders, 2001,

pp186-226.

•

Weatherall DJ, Clegg JB. The thalassemia syndromes, 4th edn.

Oxford: Blackwell Science, 2001.

Other hereditary anaemias

Weatherall DJ, Clegg JB, Higgs DR, Wood WG. The

•

Other anaemias with an important inherited component

hemoglobinopathies. In: Scriver CR, Beaudet AL, Sly WS, Valle D,

Childs B, Vogelstein B, eds. The metabolic and molecular bases of

include Fanconi’s anaemia (hypoplastic anaemia with skeletal

inherited disease, 8th edn. New York: McGraw-Hill, 2001,

deformities), Blackfan-Diamond anaemia (red cell aplasia), and

pp4571-636.

several forms of congenital dyserythropoietic anaemia.

Polycythaemia, essential thrombocythaemia, and

myelofibrosis

George S Vassiliou, Anthony R Green

Polycythaemia vera, essential thrombocythaemia and idiopathic

myelofibrosis are all clonal disorders originating from a single

aberrant neoplastic stem cell in the bone marrow. They are

generally diseases of middle or older age and have features in

common, including a potential for transforming to acute

leukaemia. Myelofibrosis may arise de novo or result from

progression of polycythaemia vera or essential

thrombocythaemia. Treatment of polycythaemia vera and

essential thrombocythaemia can greatly influence prognosis,

hence the importance of diagnosing these rare disorders early.

They need to be distinguished from other types of

polycythaemia (secondary polycythaemia, apparent

polycythaemia) and other causes of a raised platelet count

(secondary or reactive thrombocytosis), whose prognosis and

treatment are different.

Figure 4.1 Raised PCV in a patient with true polycythaemia secondary to

congenital cyanotic heart disease (left) compared to a blood sample

from a person with a normal PCV (right)

Polycythaemia

An elevation in packed cell volume (PCV), rather than a raised

haemoglobin concentration, defines polycythaemia. A raised

packed cell volume (

0.51 in males,

0.48 in females)

needs to be confirmed on a specimen taken without

Box 4.1 Classification of true polycythaemias

prolonged venous stasis (tourniquet). Patients with a

Familial/inherited

persistently raised packed cell volume should be referred to

• Mutant erythropoietin receptor

a haematologist for measurement of red cell mass by

• High oxygen affinity haemoglobin

radionuclide labelling of the red cells. Red cell mass is

Acquired

best expressed as the percentage difference between the

Primary

• Polycythaemia vera

measured value and that predicted from the patient’s

height and weight (derived from tables).

Secondary

• Hypoxia

Red cell mass measurements more than 25% above the

cardiac

predicted value constitute true or absolute polycythaemia, which

pulmonary

can be classified into aetiological categories. When the packed

central

cell volume is raised but the red cell mass is not, the condition

• Ectopic erythropoietin

is known as apparent or relative polycythaemia and is secondary to

renal disease

a reduction in plasma volume.

neoplasms

Polycythaemia vera

Presentation can be incidental but is classically associated with a

history of occlusive vascular lesions (stroke, transient ischaemic

attack, ischaemic digits), headache, mental clouding, facial

redness, itching, abnormal bleeding, or gout.

Palpable splenomegaly is present in less than half the

Initial laboratory investigations—A raised white cell count

patients with polycythaemia vera, but when present it

(

10⁹/l neutrophils) or a raised platelet count

strongly favours this diagnosis over other polycythaemias

(

400

l0⁹/l) suggest primary polycythaemia, especially if

both are raised in the absence of an obvious cause, such as

infection or carcinoma. Serum ferritin concentration should be

determined as iron deficiency may mask a raised packed cell

volume, resulting in a missed diagnosis.

Specialist investigations—Red cell mass should be determined

Box 4.2 Investigations of a raised packed cell volume

to confirm absolute polycythaemia, and secondary

• Red cell mass estimation

polycythaemia should be excluded. Most patients with primary

If red cell mass is elevated or equivocal then proceed with:

polycythaemia have a low serum erythropoietin concentration.

• Arterial blood oxygen saturation

If the spleen is not palpable then splenic sizing

• Abdominal ultrasound

(ultrasonography) should be performed to look for

• Bone marrow aspirate, trephine and cytogenetic

enlargement. Bone marrow cytogenetic analysis may reveal an

examination

acquired chromosomal abnormality which would favour a

• Serum erythropoietin level

• Culture blood for spontaneous erythroid colonies

primary marrow disorder such as polycythaemia vera. Erythroid

Polycythaemia, essential thrombocythaemia, and myelofibrosis

colony growth from blood or bone marrow in the absence of

Box 4.3 Diagnostic criteria for polycythaemia vera

added erythropoietin culture from peripheral blood would

A1 Raised red cell mass

support the diagnosis. No single pathognomonic test exists and

A2 Absence of a cause of secondary polycythaemia

the diagnosis is best made using a diagnostic algorithm

A3 Clinical (palpable) splenomegaly

(opposite).

A4 Bone marrow chromosomal abnormality

Treatment—Traditional treatment using the marrow

B1 Raised neutrophil count (

10⁹/l)

suppressant effect of radioactive phosphorus (³²P) has been

B2 Raised platelet count (

400

10⁹/l)

superseded because of the additional risk of inducing

B3 Subclinical (radiological) splenomegaly

malignancies such as acute leukaemia in later life. Repeated

B4 Erythropoietin-independent erythroid colony (BFU-E)

venesection to maintain the packed cell volume at

0.45 has

growth or low serum erythropoietin levels

become the mainstay of treatment. At this volume the risk of

To make the diagnosis of polycythaemia vera:

thrombotic episodes is much reduced. Venesection has to be

A2 A3 or A4, or

frequent at first but is eventually needed only every 6-10 weeks

A2 any two of the B criteria

in most patients. If thrombocytosis is present, concurrent

therapy to maintain the platelet count to

400

10⁹/l is

necessary. Hydroxyurea (0.5-1.5 g daily) is recommended for

this purpose and is not thought to have a pronounced

leukaemogenic potential. Some use interferon in preference

to hydroxyurea in younger patients, as this drug is not thought

to increase the long term risk of leukaemic transformation.

Low dose intermittent oral busulphan may be a convenient

alternative in elderly people. Anagrelide is a new agent that can

specifically reduce the platelet count and may be useful in

conjunction with treatment to control the packed cell volume

(see under Essential thrombocythaemia).

Normal

Progression—Long survival (

10 years) of the treated patient

Chr 20

has revealed a 20% incidence of transformation to

myelofibrosis and about 5% to acute leukaemia. The incidence

of leukaemia is further increased in those who have

transformed to myelofibrosis and those treated with ³²P or

del 20q

multiple cytotoxic agents.

Secondary polycythaemia

Many causes of secondary polycythaemia have been identified,

Figure 4.2 Deletion within the long arm of chromosome 20 in

the commonest being hypoxaemia (arterial saturation

92%)

polycythaemia vera demonstrated by fluorescent in situ hybridisation.

and renal lesions. In recent years the abuse of drugs such as

(Red, probe for centromere of chromosome 20; green, probe for long

erythropoietin and anabolic steroids should also be considered

arm of chromosome 20)

in the right context. Investigations are designed to determine

the underlying disorder to which the polycythaemia is

secondary.

Box 4.4 Aims of treatment in polycythaemia vera

Treatment is aimed at removing the underlying cause when

• Maintain packed cell volume to

0.45

practicable. In hypoxaemia, in which the risk of vascular

• Reduce platelet count to

400

10⁹/l

occlusion is much less pronounced than in polycythaemia vera,

venesection is usually undertaken only in those with a very high

packed cell volume. At this level the harmful effects of

increased viscosity no longer outweigh the oxygen carrying

Box 4.5 Causes of a raised platelet count

benefits of a raised packed cell volume. Reduction to a packed

• Reactive thrombocytosis

cell volume of 0.50-0.52 may result in an improvement of

Infection

cardiopulmonary function. In practice the symptoms

Malignancy

Inflammatory diseases

experienced by individual patients often decide the target

Haemorrhage

packed cell volume. In polycythaemia associated with renal

Post-surgery

lesions or other tumours, the packed cell volume should

Post-splenectomy

generally be reduced to

0.45.

• Myeloproliferative disorders

• Chronic myeloid leukaemia

• Myelodysplasia (some forms only)

Apparent polycythaemia

In apparent or relative polycythaemia red cell mass is not

increased and the raised packed cell volume is secondary to

a decrease in the volume of plasma. An association exists

with smoking, alcohol excess, obesity, diuretics, and

hypertension.

The need for treatment is uncertain. Lowering the packed

cell volume by venesection is undertaken only in patients who

have a significantly increased risk of vascular complications for

other reasons. On follow up one-third of patients revert

spontaneously to a normal packed cell volume.

ABC of Clinical Haematology

Essential thrombocythaemia

Like polycythaemia vera and idiopathic myelofibrosis, essential

thrombocythaemia is one of the group of clonal conditions

known as the myeloproliferative disorders.

A persisting platelet count

600

10⁹/l is the central

diagnostic feature, but other causes of a raised platelet count

need to be excluded before a diagnosis of essential

thrombocythaemia can be made.

Laboratory investigations

Investigations may reveal other causes of raised platelet count.

Apart from a full blood count and blood film they should also

include erythrocyte sedimentation rate, serum C reactive

protein and serum ferritin, bone marrow aspirate, trephine,

and cytogenetic analysis. Although the latter is generally

Figure 4.3 Toe ischaemia in a patient with essential thrombocythaemia

normal in essential thrombocythaemia, certain abnormalities

may favour a diagnosis of myelodysplasia or iron deficient

Gangrene of the toes in the presence of good peripheral

(masked) polycythaemia vera and it is important to exclude the

pulses and a raised platelet count strongly suggests primary

thrombocythaemia

presence of a Philadelphia chromosome, which would indicate

a diagnosis of chronic myeloid leukaemia.

Presentation and prognosis

Thirty to fifty per cent of patients with essential

thrombocythaemia have microvascular occlusive events: for

example, burning pain in extremities (erythromelalgia) or

digital ischaemia, major vascular occlusive events, or

haemorrhage at presentation. These are most pronounced in

elderly people, in whom the risk of cerebrovascular accident,

myocardial infarction, or other vascular occlusion is high if left

untreated. Patients with pre-existing vascular disease will also be

at higher risk of such complications. The risk in young patients

is lower, though major life threatening events have been

described. Transformation to myelofibrosis or acute

leukaemia may occur in the long term in a minority of

patients.

Treatment and survival

Figure 4.4 Bone marrow trephine biopsy from a patient with essential

All patients should receive daily low dose aspirin, unless

thrombocythaemia showing clustering of megakaryocytes (arrows)

contraindicated because of bleeding or peptic ulceration.

If there is palpable splenomegaly, a raised platelet count is

This reduces the risk of vascular occlusion but may increase

much more likely to be due to primary thrombocythaemia

the risk of haemorrhage, particularly at very high platelet

than to reactive thrombocytosis

counts.

Reduction of the platelet count by cytotoxic agents (daily

The risk of occlusive vascular lesions is very small in

hydroxyurea, or intermittent low dose busulphan in elderly

reactive thrombocytosis but high in primary

people) reduces the incidence of vascular complications and

thrombocythaemia

appreciably improves survival in older patients (from about

three years in untreated patients to 10 years or more in treated

patients). The newer drug anagrelide is used increasingly in

view of its specificity to the platelet lineage (it selectively

inhibits megakaryocyte differentiation) and because of an

expectation that it will not increase the long term risk of

leukaemic transformation. Interferon has also been used and

is particularly useful in pregnancy.

The Medical Research Council “Primary

Thrombocythaemia 1” trial is currently comparing the use of

hydroxyurea and anagrelide in patients with essential

thrombocythaemia and a high risk of thrombosis.

Idiopathic myelofibrosis

The main features are bone marrow fibrosis, extramedullary

haemopoiesis (production of blood cells within organs other

than the bone marrow), splenomegaly, and leucoerythroblastic

Figure 4.5 Bone marrow trephine biopsy from a patient with advanced

blood picture (immature red and white cells in the peripheral

idiopathic myelofibrosis. Note the marked linear reticulin staining (arrow)

Polycythaemia, essential thrombocythaemia, and myelofibrosis

blood). Good evidence exists that the fibroblast proliferation is

secondary (reactive) and not part of the clonal process. In

some patients, the fibrosis is accompanied by new bone

formation (osteomyelosclerosis). Idiopathic myelofibrosis needs

to be distinguished from causes of secondary myelofibrosis (see

below).

Presentation

Idiopathic myelofibrosis may have been present for many years

before diagnosis. Patients could have had previous

undiagnosed primary polycythaemia or thrombocythaemia.

The absence of palpable splenomegaly is rare. The main

presenting features are abdominal mass (splenomegaly), weight

loss (hypermetabolic state), anaemia, fatigue, and bleeding.

Fevers and night sweats may be present and are associated with

a worse outcome.

Laboratory investigations

A leucoerythroblastic blood picture is characteristic but not

diagnostic of idiopathic myelofibrosis as it can occur in cases of

marrow infiltration (eg by malignancy, amyloidosis,

tuberculosis, osteopetrosis) severe sepsis, severe haemolysis,

after administration of haemopoietic growth factors as well as

in various types of chronic leukaemia. The blood count is

variable. In the initial “proliferative phase” red cell production

may be normal or even increased. About half of presenting

patients may have a raised white cell count or platelet count

(absence of the Philadelphia chromosome will distinguish

Figure 4.6 Leucoerythroblastic blood film in a patient with idiopathic

myelofibrosis. Note the nucleated red blood cell (arrowhead) and the

from chronic myeloid leukaemia). As the bone marrow

myelocyte (arrow)

becomes more fibrotic, the classic “cytopenic phase”

supervenes.

Progression and management

The median survival of 2-4 years may be much longer in

patients who are asymptomatic at presentation. More recently it

has been shown that the presence of anaemia, a very high or

low white cell count, the presence of bone marrow

Box 4.6 Causes of a leucoerythroblastic blood film

chromosomal abnormalities and an advanced patient age are

all associated with worse prognosis.

• Idiopathic myelofibrosis

Bone marrow transplantation from a matched sibling or

• Bone marrow infiltration

• Severe sepsis

unrelated donor should be offered to young patients with poor

• Severe haemolysis

prognostic features. This is the only curative treatment modality

• Sick neonate

for myelofibrosis, but in view of its toxicity it cannot be

performed in the majority of patients with this disorder, who

are over 50 years old at diagnosis.

Supportive blood transfusion may be needed for anaemic

patients. Cytotoxic agents may be useful in the proliferative

phase, particularly if the platelet count is raised. More recently

antifibrotic and antiangiogenic agents such as thalidomide have

been used to inhibit progression of fibrosis but success has

been limited and there is no convincing evidence that such

treatment improves survival. Androgenic steroids such as

Box 4.7 Bad prognostic features in myelofibrosis

danazol and oxymethalone can improve the haemoglobin in a

• Hb

10 g/dl

proportion of anaemic patients.

• WCC

4 or

10⁹/l

Splenectomy may improve the quality of life (though not

• Bone marrow chromosomal abnormalities

the prognosis) by reducing the need for transfusions or the

• Advanced patient age

pain sometimes associated with a very enlarged spleen.

• Raised number of CD34-positive cells in the peripheral

Operative morbidity and mortality can be high and are usually

blood

secondary to haemorrhage, making preoperative correction of

coagulation abnormalities imperative. Low dose irradiation of

the spleen may be helpful in frail patients.

Death can be due to haemorrhage, infection or

transformation to acute leukaemia. Portal hypertension with

varices, iron overload from blood transfusion, and compression

of vital structures by extramedullary haemopoietic masses may

also contribute to morbidity.

Chronic myeloid leukaemia

John Goldman

Chronic myeloid leukaemia is a clonal malignant

Box 5.1 Clinical features in patients with chronic

myeloproliferative disorder believed to originate in a single

myeloid leukaemia at diagnosis

abnormal haemopoietic stem cell. The progeny of this

Common

abnormal stem cell proliferate over months or years such that,

• Fatigue

by the time the leukaemia is diagnosed, the bone marrow is

• Weight loss

grossly hypercellular and the number of leucocytes is greatly

• Sweating

increased in the peripheral blood. Normal blood cell

• Anaemia

production is almost completely replaced by leukaemia cells,

• Haemorrhage—eg easy bruising, discrete ecchymoses

which, however, still function almost normally.

• Splenomegaly with or without hepatomegaly

Chronic myeloid leukaemia has an annual incidence of 1 to

Rare

• Splenic infarction

1.5 per 100 000 of the population (in the United Kingdom

• Leucostasis

about 700 new cases each year), with no clear geographical

• Gout

variation.

• Retinal haemorrhages

Presentation may be at any age, but the peak incidence is at

• Priapism

age 50-70 years, with a slight male predominance. This

• Fever

leukaemia is very rare in children.

Most cases of chronic myeloid leukaemia occur

sporadically. The only known predisposing factor is irradiation,

as shown by studies of Japanese survivors of the atomic bombs

and in patients who received radiotherapy for ankylosing

spondylitis.

The clinical course of chronic myeloid leukaemia can be

divided into a chronic or “stable” phase and an advanced

phase, the latter term covering both accelerated and blastic

phases. Most patients present with chronic phase disease, which

lasts on average 4-5 years. In about two-thirds of patients the

chronic phase transforms gradually into an accelerated phase,

Box 5.2 Survival from chronic myeloid leukaemia

characterised by a moderate increase in blast cells, increasing

anaemia or thrombocytosis, or other features not compatible

• The average survival from diagnosis is 5-6 years, but the

range is wide

with chronic phase disease. After a variable number of months

• Occasionally patients die within one year of diagnosis

this accelerated phase progresses to frank acute blastic

• About 3% of patients may live more than 15 years without

transformation. The remaining one-third of patients move

radical therapy

abruptly from chronic phase to an acute blastic phase (or

blastic crisis) without an intervening phase of acceleration.

Pathogenesis

All leukaemia cells in patients with chronic myeloid leukaemia

contain a specific cytogenetic marker, described originally in

1960 by workers in Philadelphia and now known as the

Philadelphia or Ph chromosome.

The Ph chromosome is derived from a normal 22

chromosome that has lost part of its long arm as a result of a

balanced reciprocal translocation of chromosomal material

involving one of the 22 and one of the 9 chromosomes. The

translocation is usually referred to as t(9;22)(q34;q11). Thus

the Ph chromosome (also known as 22q

) appears somewhat

Philadelphia

shorter than its normal counterpart and the 9q somewhat

chromosome

longer than the normal 9.

(22q-)

The Ph chromosome carries a specific fusion gene known

as BCR-ABL, which results from juxtaposition with part of the

Fusion mRNA

p210 protein

Resultant chronic

ABL proto-oncogene (from chromosome 9) with part of the

myeloid leukaemia

BCR gene on chromosome 22. This fusion gene is expressed as

a specific messenger RNA (mRNA), which in turn generates a

Fusion

protein called p210^BCR-ABL. This protein perturbs stem cell

gene

kinetics, resulting in the chronic phase of chronic myeloid

leukaemia, although the exact mechanism remains unclear.

Researchers have recently developed a drug (imatinib

mesylate) that blocks the action of the BCR-ABL gene and

Figure 5.1 Formation of the Philadelphia chromosome resulting in a

thereby reverses the leukaemic phenotype in chronic myeloid

BCR-ABL fusion gene that generates a fusion protein (p210) responsible

leukaemia cells.

for the chronic myeloid leukaemia phenotype

ABC of Clinical Haematology

Box 5.3 Usual peripheral blood findings in chronic

myeloid leukaemia at diagnosis

• Raised white blood cell count (30-400

10⁹/l).

Differential shows:

Granulocytes at all stages of development

Increased numbers of basophils and eosinophils

Blast (primitive) cells (maximum 10%)—never present in

the blood of normal people

•

Haemoglobin concentration may be reduced; red cell

morphology is usually unremarkable; nucleated (immature)

red cells may be present

•

Platelet count may be raised (300-600

10⁹/l)

The spleen may be greatly enlarged before onset of

symptoms. Treatment that reduces leucocyte count to

normal usually restores the spleen to normal size

Figure 5.2 Patient with massive splenomegaly in chronic phase chronic

myeloid leukaemia

Chronic phase disease

Presentation

The characteristic symptoms at presentation include fatigue,

weight loss, sweating, anaemia, haemorrhage or purpura, and

the sensation of a mass in the left upper abdominal quadrant

(spleen). Often the disease is detected as a result of routine

blood tests performed for unrelated reasons, and a fifth of

patients are totally asymptomatic at the time of diagnosis. The

spleen may be greatly enlarged before onset of symptoms.

Treatment that reduces the leucocyte count to normal usually

restores the spleen to normal size. Much rarer features at

presentation include non-specific fever, lymphadenopathy,

visual disturbances due to leucostasis (a form of hyperviscosity

caused by an extremely high white cell count) or retinal

haemorrhages, splenic pain due to infarction, gout, and

occasionally priapism.

The commonest physical sign at diagnosis is an enlarged

spleen, which may vary from being just palpable at the left

Figure 5.3 Peripheral blood film from patient with chronic myeloid

costal margin to filling the whole left side of the abdomen and

leukaemia showing many mature granulocytes, including two basophils

extending towards the right iliac fossa. The liver may be

(arrow); a blast cell is prominent (double arrow)

enlarged, with a soft, rather ill defined lower edge.

Spontaneous and excessive bruising in response to minor

trauma is common.

Diagnosis

The diagnosis of chronic myeloid leukaemia in chronic phase

can be made from study of the peripheral blood film, which

Box 5.4 Investigations to confirm suspected chronic

shows greatly increased numbers of leucocytes with many

myeloid leukaemia

immature forms (promyelocytes and myelocytes); the marrow is

Routine

usually examined to confirm the diagnosis.

• Full blood count including blood film

Marrow examination shows increased cellularity. The

• Neutrophil alkaline phosphatase

distribution of immature leucocytes resembles that seen in the

• Urea, electrolytes

blood film. Red cell production is relatively reduced.

• Serum lactate dehydrogenase

Megakaryocytes, the cells giving rise to platelets, are plentiful

• Bone marrow aspirate (degree of cellularity, chromosome

analysis)

but may be smaller than usual.

Optional

Cytogenetic study of marrow shows the presence of the Ph

• Bone marrow trephine biopsy (extent of fibrosis)

chromosome in all dividing cells.

• BCR-ABL chimeric gene by fluorescent in situ

The patient’s blood concentrations of urea and electrolytes

hybridisation or by polymerase chain reaction

are usually normal at diagnosis, whereas the lactate

• Vitamin B₁₂ and B₁₂ binding capacity

dehydrogenase is usually raised. Serum urate concentration

• HLA typing for patient and family members

may be raised.

Chronic myeloid leukaemia

Management

Box 5.5 Treatment with hydroxyurea

After diagnosis, the first priority is a frank discussion with the

• Hydroxyurea inhibits the enzyme ribonucleotide reductase

patient. It is now customary to use the term leukaemia in this

and acts specifically on cells of the myeloid series—ie

discussion and to explain to the patient that he or she may

neutrophils, eosinophils, basophils, etc

expect to live for several years with a near normal lifestyle. The

• It is useful for rapid reduction of the leucocyte count in

clinician should explain the propensity of the disease to

newly diagnosed patients

progress to an advanced phase. The choice of treatment with

• Many haematologists start treatment with hydroxyurea then

imatinib mesylate (STI571, Glivec), interferon or

switch to interferon once the patient’s symptoms are

relieved and the leucocyte count is restored to normal

hydroxyurea should be discussed.

• Hydroxyurea is also valuable for controlling chronic phase

If chronic myeloid leukaemia is diagnosed in pregnancy the

disease in patients who cannot tolerate interferon

woman should have the chance to continue to term. Chronic

• It is usually started at 2.0 g daily by mouth; the usual

myeloid leukaemia has no adverse effect on pregnancy and

maintenance dose is 1.0-1.5 g daily, titrated against the

pregnancy has no adverse effect on the leukaemia.

leucocyte count

The clinician may wish to mention at this point the

• Treatment with hydroxyurea does not eradicate cells with

existence of patient information booklets produced by BACUP

the Ph chromosome

• Side effects are rare but include rashes, mouth ulceration,

(British Association of Cancer United Patients) and by the

and gastrointestinal symptoms. The drug causes

Leukaemia Research Fund, which are extremely valuable as

macrocytosis and megaloblastoid changes in the marrow

many patients will not retain all that is said at this first

interview. There are also a number of useful websites available

on the Internet, though some of these are somewhat

one-sided.

Imatinib mesylate (STI571)—Imatinib mesylate has just

become generally available and seems already to be the

treatment of choice for chronic myeloid leukaemia presenting

in chronic phase. It acts by specifically inhibiting the enhanced

protein tyrosine kinase activity of the BCR-ABL oncoprotein

and thus reversing the pathologically perturbed signal

transduction. Preliminary clinical studies show that it induces

complete haematological remission in

95% of previously

untreated patients and at least 50% of these will achieve a

complete cytogenetic remission. Toxicity seems to be relatively

mild. It is too early to say whether the drug will prolong life in

comparison with interferon used alone or in conjunction

with cytarabine.

Interferon

—Interferon is a member of a family of

Younger men should be offered cryopreservation of semen

naturally occurring glycoproteins with antiviral and

if necessary

antiproliferative actions. It was until recently the drug of choice

for managing chronic myeloid leukaemia in the chronic phase.

It restores spleen size and blood counts to normal in 70-80% of

patients. Some 10-20% of patients achieve a major reduction or

complete disappearance of cells with the Ph chromosome from

their bone marrow (tantamount to complete cytogenetic

remission). Interferon initially causes flu-like symptoms, but

these usually subside. Other more persistent side effects

include anorexia, weight loss, depression, alopecia, rashes,

neuropathies, autoimmune disorders, and thrombocytopenia.

Newly diagnosed patients

(n=100)

Currently interferon should be considered for chronic phase

patients resistant to imatinib mesylate.

Allogeneic stem cell transplantation—Patients under the age of

Aged 55 years

Aged >55 years

60 years who have siblings with identical HLA types may be

(n=55)

(n=45)

offered treatment by high dose cytoreduction (chemotherapy

and radiotherapy) followed by transplantation of haemopoietic

With HLA-

With no HLA-

Conventionally

stem cells collected from the donor’s bone marrow or

identical siblings

too old for

peripheral blood. With typical family size in western Europe,

(n=15)

(n=40)

allogeneic

about 30% of patients will have matched sibling donors. In

transplantation

selected cases transplants may also be performed with HLA-

"Cured" after

"Matched"

identical unrelated donors. Allogeneic stem cell transplants are

allografting

unrelated donors

associated with an appreciable risk of morbidity and mortality,

(n=10)

(n=20)

and in general, older patients (aged 40-60) fare less well than

younger patients. Nevertheless, the projected cure rate after

allogeneic stem cell transplantation is about 60-70%.

"Cured" after

Autologous stem cell transplantation—For patients up to the

allografting

age of 65 years for whom an allograft is excluded, autografting

(n=7)

may be considered. For this purpose haemopoietic stem cells

are collected from the patient’s blood or marrow and

Figure 5.4 Eligibility for and results of allogeneic transplantation for

cryopreserved. The patient then receives high dose

unselected 100 newly diagnosed patients

ABC of Clinical Haematology

cytoreductive chemotherapy, followed by reinfusion of the

Box 5.6 Criteria for advanced phase disease

thawed stem cells. The procedure may prolong life in some

• Increasing splenomegaly despite full doses of cytotoxic

cases, and remains experimental.

drugs

• Rapid white blood cell doubling time

•

White blood cell count poorly responsive to full doses of

cytotoxic drugs

Advanced phase disease

• Anaemia or thrombocytopenia unresponsive to cytotoxic

drugs

Presentation

• Persistent thrombocytosis (

1000

10⁹/l)

Advanced phase disease may be diagnosed incidentally as a

•

10% blasts in peripheral blood or marrow

•

20% blasts plus promyelocytes in blood or marrow

result of a blood test at a routine clinic visit. Alternatively the

• Acquisition of “non-random” chromosomal changes in

patient may have excessive sweating, persistent fever, or

addition to presence of Philadelphia chromosome

otherwise unexplained symptoms of anaemia, splenic

• Development of myelofibrosis

enlargement or splenic infarction, haemorrhage, or bone pain.

At times the advanced phase can be difficult to distinguish

In most cases the blast crisis is myeloid (that is, resembling

from the chronic phase and can be diagnosed with confidence

acute myeloid leukaemia), and in a fifth of cases lymphoid blast

only in retrospect

crisis occurs.

Occasionally patients progress to a myelofibrotic phase of

the disease, in which intense marrow fibrosis predominates,

blast cells proliferate less aggressively, and the clinical picture is

Chronic phase

characterised by splenomegaly and pancytopenia consequent

on marrow failure.

Accelerated phase

Management

Advanced

Patients in accelerated phase may derive considerable benefit

phase

Acute (blastic) transformation

disease

from imatinib mesylate, which can re-establish chronic phase

(80% myeloid, 20% lymphoid)

disease and even Ph-negative haemopoiesis in some cases. They

may also respond to hydroxyurea or busulphan if they have not

previously received these agents. Splenectomy may be useful to

Figure 5.5 Progression of chronic myeloid leukaemia, showing

improve thrombocytopenia or symptoms due to splenomegaly.

progression to blastic phase

Patients in a blastic phase respond only transiently to imatinib

mesylate. It is probably preferable to rely on the use of

combination chemotherapy, though the possibility of treating

Further reading

localised pain or resistant splenomegaly by radiotherapy should

• Sawyers C. Chronic myeloid leukemia. N Engl J Med 1999;340:

not be forgotten. For those patients with myeloid

1330-40.

transformations, drugs suitable for treating acute myeloid

• Deininger M, Goldman JM, Melo JM. The molecular biology of

leukaemia will control the leukaemic proliferation for a time.

chronic myeloid leukemia. Blood 2000;96:3343-56.

About 30% of patients will achieve a second chronic phase

• Hasford J, Pfirrmann J, Hehlmann R et al. A new prognostic

score for survival of patients with chronic myeloid leukemia

compatible with a normal lifestyle for months or years. Patients

treated with interferon alfa. JNCI 1998;90:850-8.

with lymphoid transformations should be treated with drugs

• Guilhot F, Chastang C, Michallet M et al. Interferon alpha 2b

appropriate to adult acute lymphoblastic leukaemia. Second

combined with cytarabine versus interferon alone in chronic

chronic phase may be achieved in 40-60% of cases, more

myelogenous leukemia. N Engl J Med 1997;337:223-9.

commonly in those who had a short interval from diagnosis to

• Goldman JM, Druker B. Chronic myeloid leukemia: current

transformation. Patients restored to second chronic phase

treatment options. Blood 2001;98:2039-42.

• Kantarjian H, Sawyers C, Hochhaus A et al. Hematologic and

should receive prophylaxis against neuroleukaemia, comprising

cytogenetic responses to imatinib mesylate in chronic

five or six intrathecal injections of methotrexate, but there is

myelogenous leukemia. N Engl J Med 2002;346;645-52.

no indication for cranial or craniospinal irradiation.

The acute leukaemias

T Everington, R J Liesner, A H Goldstone

Acute leukaemia is a clonal (that is, derived from a single cell)

Box 6.1 Aetiological factors in acute leukaemia

malignant disorder affecting all age groups with an average

• Unknown (usually)

annual incidence rate of 4-7 people per 100 000. It is

• Hereditary

characterised by the accumulation of immature blast cells in

Down’s syndrome

the bone marrow, which replace normal marrow tissue,

Bloom’s syndrome

including haemopoietic precursor cells. This results in bone

Fanconi’s anaemia

marrow failure, reflected by peripheral blood cytopenias and

Ataxia telangiectasia

circulating blast cells. Infiltration of various organs is also a

Kleinfelter’s syndrome

Osteogenesis imperfecta

feature of some forms of leukaemia.

Wiskott-Aldrich syndrome

In most cases the aetiology is not obvious, but internal and

Leukaemia in siblings

external factors associated with damage to DNA can predispose

• Chemicals

to acute leukaemia. Over 50 years, progressive advances in the

Chronic benzene exposure

treatment of acute leukaemia have converted an incurable

Alkylating agents (chlorambucil, melphalan)

disease to one in which complete remissions can be obtained in

• Radiation

up to 95% of selected patients treated with curative intent. This

• Predisposing haematological diseases (myeloproliferative

disorders, myelodysplasia, and aplastic anaemia)

has largely been the result of ongoing clinical trials, improved

• Viruses (HTLV-I causing adult T cell leukaemia/lymphoma)

supportive treatment and the development of bone marrow

transplantation for those in higher risk categories.

Classification

Acute leukaemia is subdivided into (a) acute lymphoblastic

leukaemia (ALL), in which the abnormal proliferation is in the

lymphoid progenitor cells (that is, immature lymphocytes) and

(b) acute myeloid leukaemia (AML), which involves the

myeloid lineages (that is, cells from which neutrophils,

Box 6.2 FAB* Classification of acute myeloid

eosinophils, monocytes, basophils, megakaryocytes, etc. are

leukaemia

derived). The distinction between the two leukaemias is based

Acute myeloid leukaemia with minimal evidence of

on morphological, cytochemical, immunological and

myeloid differentiation

cytogenetic differences and is of paramount importance as the

Acute myeloblastic leukaemia without maturation

treatment and prognosis are usually different.

Acute myeloblastic leukaemia with maturation

Both acute lymphoblastic leukaemia and acute myeloid

Acute promyelocytic leukaemia

leukaemia are currently further subdivided on the basis of

Acute myelomonocytic leukaemia

morphological criteria: acute lymphoblastic leukaemia into FAB

Acute monocytic/monoblastic leukaemia

Acute erythroleukaemia

(French-American-British) subtypes L1, L2, and L3, and acute

Acute megakaryoblastic leukaemia

myeloid leukaemia into FAB subtypes M0 to M7.

On the basis of surface antigen expression, acute

*French-American-British

lymphoblastic leukaemia is divided into T cell lineage and

B cell lineage. B cell lineage is further subdivided: early B

precursor acute lymphoblastic leukaemia is the most immature

and is negative for the common acute lymphoblastic leukaemia

antigen (CD 10); common acute lymphoblastic leukaemia and

pre-B cell acute lymphoblastic leukaemia are more mature and

are CD 10 positive; and B cell acute lymphoblastic leukaemia is

the most mature and is the only one to express surface

immunoglobulin. Little correlation exists between

morphological subtype and immunophenotype or prognosis in

L1 or L2 acute lymphoblastic leukaemia. L3 morphology is

almost exclusively found in B cell acute lymphoblastic

leukaemia.

In acute myeloid leukaemia immunophenotyping may not

help to distinguish between leukaemias of the myeloid (M0 to

M3), the myelomonocytic (M4), and the monocytic (M5)

lineages, and special cytochemical stains are usually used to

support morphological findings. In erythroleukaemia (M6) and

megakaryoblastic leukaemia (M7), however, the surface antigen

expression is often diagnostic.

The FAB classification system, while essentially simple,

has several deficiencies, not least a lack of clear

Figure 6.1 Blood film of patient with acute lymphoblastic leukaemia

ABC of Clinical Haematology

diagnostic/prognostic association. A Clinical Advisory

Committee to the World Health Organization (WHO) has now

published a new classification system which is based around

cytogenetic abnormalities, and which thereby seeks to define

biological and clinical entities more closely. It is likely that this

will be adopted in the near future.

Incidence

Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia is most common in the age

range 2-10 years, with a peak at 3-4 years. The incidence then

Figure 6.2 Blood film of patient with acute myeloid leukaemia

decreases with increasing age, though there is a secondary rise

after 40 years. In children it is the most common malignant

Acute lymphoblastic leukaemia is slightly more common

disease and accounts for 85% of childhood leukaemia.

among males than females

Acute myeloid leukaemia

Acute myeloid leukaemia accounts for 10-15% of childhood

Acute myeloid leukaemia is equally common among males

leukaemia, but it is the commonest leukaemia of adulthood,

and females

particularly as chronic myeloproliferative disorders and

preleukaemic conditions such as myelodysplasia usually

progress to acute myeloid leukaemia rather than acute

lymphoblastic leukaemia. The incidence increases with age,

and the median age at presentation is 60 years.

Presentation

Acute leukaemia is always serious and life threatening, and all

patients suspected of having this condition should be

immediately referred for urgent assessment.

Common symptoms and signs at presentation result from

bone marrow failure or, less commonly, organ infiltration.

Anaemia can result in pallor, lethargy, and dyspnoea.

Neutropenia results in predominantly bacterial infections of

Figure 6.3 Severe gum swelling at presentation in acute myeloid

leukaemia M5

the mouth, throat, skin, chest or perianal region.

Thrombocytopenia may present as spontaneous bruising,

menorrhagia, bleeding from venepuncture sites, gingival

bleeding, or prolonged nose bleeds.

A common presenting feature resulting from organ

infiltration in childhood acute lymphoblastic leukaemia is bone

pain, but acute lymphoblastic leukaemia can also present with

superficial lymphadenopathy, abdominal distension due to

abdominal lymphadenopathy and hepatosplenomegaly,

respiratory embarrassment due to a large mediastinal mass,

testicular enlargement, or a meningeal syndrome. Gum

hypertrophy and skin infiltration are more commonly seen in

acute myeloid than in acute lymphoblastic leukaemia.

Figure 6.4 Infiltration of optic fundus by acute lymphoblastic leukaemia

Investigations

Full blood count usually but not invariably shows reduced

haemoglobin concentration and platelet count. The white cell

Box 6.3 Differential diagnosis of acute leukaemia

count can vary from

1.0

10⁹/l to

200

10⁹/l, and the

• If lymphadenopathy: infections such as infectious

differential white cell count is often abnormal, with

mononucleosis or lymphoma

neutropenia and the presence of blast cells. The anaemia is a

• If hepatosplenomegaly: myeloproliferative or

lymphoproliferative disorder, myelodysplasia, metabolic,

normochromic, normocytic anaemia, and the

storage or autoimmune disorders (rarely, tropical disease, eg

thrombocytopenia may be severe (platelet count

10⁹/l).

visceral leishmaniasis)

Coagulation screening may yield abnormal results, particularly

• If no peripheral leukaemic blasts but pancytopenia: aplastic

in promyelocytic leukaemia (acute myeloid leukaemia M3)

anaemia or infiltrated bone marrow involvement from non-

when granules from the leukaemic blasts can have

haemopoietic small round cell tumour

procoagulant activity and trigger a consumptive coagulopathy.

• Myelodysplasia

Biochemical screening is particularly important if the leucocyte

• Lymphoblastic lymphoma: lymphomatous presentation with

25% of blasts in the marrow (distinction may be arbitrary

count is very high, when there may be evidence of renal

as treatment may be the same)

impairment and hyperuricaemia.

The acute leukaemias

Chest radiography is mandatory to exclude the presence of a

mediastinal mass, which is present in up to 70% of patients with

T cell acute lymphoblastic leukaemia. In childhood acute

lymphoblastic leukaemia lytic bone lesions may also be seen.

Bone marrow aspiration with or without trephination is

essential to confirm acute leukaemia. The marrow is usually

hypercellular, with a predominance of immature (blast) cells.

Immunophenotyping of the antigens present on blasts isolated

from the bone marrow or peripheral blood is the most reliable

method of determining whether the leukaemia is lymphoid or

myeloid, and cytochemistry helps to confirm myeloid or

monocytic origin.

Cytogenetics and molecular studies often detect abnormalities

within the leukaemic clone that can have diagnostic or

prognostic value—for example, the Philadelphia chromosome,

which is the product of a translocation between chromosomes

Figure 6.5 Interphase fluorescent in situ hybridisation using probes for

9 and 22, the presence of which confers a very poor prognosis

BCR and ABL genes. Left: Normal cell showing two red dots (two normal

in cases of acute lymphoblastic leukaemia.

copies of BCR) and two yellow dots (two normal copies of ABL). Right:

Atraumatic lumbar puncture with cerebrospinal fluid cytospin

Cell from child with Ph chromosome positive acute lymphoblastic

leukaemia with translocation of chromosomes 9 and 22

is an important initial staging investigation in ALL or AML with

neurological symptoms to detect leukaemic cells in the

cerebrospinal fluid, indicating involvement of the central

nervous system.

Box 6.4 Management of acute leukaemia

• Immediate (same day) referral to specialist

•

Prompt diagnosis

• Early treatment

Management

• Intensive supportive care

• Systemic chemotherapy

All patients who have either suspected or confirmed acute

• Treatment directed at central nervous system (in children

leukaemia should be referred for specialist advice, assessment,

and in adult acute lymphoblastic leukaemia)

and treatment. Which centre a patient is referred to, and the

• Minimising early and late toxicity of treatment

type of treatment given, will depend on the patient’s age and

condition. Children and young adults should always be treated

in recognized specialist centres to maximise the chance of cure

with minimal toxicity. On admission to a specialist unit the

Adequate hydration and allopurinol are essential at the

patient will need chemotherapy to treat the leukaemia and

start of treatment to reduce the risk of hyperkalaemia,

supportive care to ameliorate or correct the effects of the

hyperuricaemia, and renal damage

leukaemia and to facilitate treatment.

Supportive care

The numerical threshold for blood product transfusion has

progressively lowered. Prophylactic platelet transfusions are

given if the platelet count is

10⁹/l. Bleeding episodes

predominantly result from thrombocytopenia and should be

treated accordingly. Clotting abnormalities may result from a

consumptive coagulopathy where infusions of fresh frozen

plasma and cryoprecipitate may be beneficial. Packed red cell

transfusions are given for symptomatic anaemia, though these

are contraindicated if the white cell count is extremely high.

In most patients a central venous catheter has to be inserted

to facilitate blood product support, administration of

chemotherapy and antibiotics, and frequent blood sampling.

Serious infection is a common cause of death in patients

with acute leukaemia, as bone marrow failure due to the

leukaemia and to chemotherapy often results in profound

neutropenia for two weeks or more. Reverse-barrier nursing

techniques should therefore be used for such patients, and

Figure 6.6 Pseudomonas infection of skin and nail bed in patient having

treatment for acute myeloid leukaemia

intravenous antimicrobial agents should be started as soon as

there is a fever or other sign of infection.

Psychological and social support to patients and families of

patients with leukaemia is important, and specialist centres

Chemotherapy

have networks to provide this

The aim of chemotherapy for leukaemia is initially to induce

a remission (

5% blasts in the bone marrow) and then to

eradicate the residual leukaemic cell population by further

courses of consolidation therapy. The drugs damage the

capacity of the leukaemic cells to divide and replicate, and

using cyclical combinations of three or more drugs increases

ABC of Clinical Haematology

the cytotoxic effect, improves the chance of remission after the

Table 6.1 Poor prognosis in acute lymphoblastic leukaemia

initial “induction” period, and reduces the emergence of drug

resistance. In Britain acute myeloid leukaemia is currently

Factors

Acute lymphoblastic leukaemia

treated with four or five courses of intensive chemotherapy

Age

1 year or

10 years

when there is intent to cure. Each course entails up to 10 days

Sex

Male

of chemotherapy. Subsequent courses are commenced after cell

Presenting white

10⁹/l

counts have recovered and response to treatment is established.

blood cells

During the recovery phase the patient is severely

Central nervous

Presence of blasts in cerebrospinal fluid

myelosuppressed and needs inpatient blood product support

system disease

at presentation

and antimicrobial drugs. In acute myeloid leukaemia M3 the

Remission problems

Failure to remit after first induction

drug ATRA (all-trans-retinoic acid) is used as an adjunct to

treatment

chemotherapy as it causes differentiation of the malignant

Cytogenetics

Philadelphia positive—that is,

clone.

t(9;22)—or t(4;11)acute

In acute lymphoblastic leukaemia the induction course is

lymphoblastic leukaemia

followed by two or more consolidation periods and by

treatment directed at the central nervous system (see below),

followed by long term maintenance or continuation treatment

Table 6.2 Poor prognosis in acute myeloid leukaemia

for up to two years. This has been shown to improve long term

Factors

Acute myeloid leukaemia

cure rates in acute lymphoblastic leukaemia, though not in

acute myeloid leukaemia.

Age

60 years

Some aggressive leukaemia subtypes such as adult T cell

Sex

Male or female

leukaemia and Burkitt’s lymphoma/leukaemia have shown

Presenting white

10⁹/l

marked responsiveness to short term intensive treatment

blood cells

schedules. Complete remission rates of 65-86% have been

Central nervous

Presence of blasts in cerebrospinal

achieved in a disease that previously had an extremely poor

system disease

fluid at presentation (rare)

prognosis.

Remission problems

20% blasts in bone marrow after

first course of treatment

Treatment directed at the central nervous system

Cytogenetics

Deletions or monosomy of chromosome

5 or 7 or complex chromosomal

The treatment or prevention of leukaemic cells in the central

abnormalities

nervous system is part of all treatment protocols in childhood

leukaemia and adult acute lymphoblastic leukaemia, but not in

adults with acute myeloid leukaemia unless they have symptoms

or blasts are present in the cerebrospinal fluid. Treatment

Box 6.5 Ongoing Medical Research Council clinical

directed at the central nervous system generally comprises

trials

regular intrathecal chemotherapy (usually methotrexate), high

• Acute lymphoblastic leukaemia in both children and adults

dose intravenous methotrexate, or cranial irradiation.

• Relapsed acute lymphoblastic leukaemia in children

• Acute myeloid leukaemia in patients aged

60 years

Bone marrow transplantation

• Acute myeloid leukaemia in patients aged

55 years

Up to 85% of patients who initially achieve a complete

remission will subsequently relapse. Transplantation reduces

relapse risk but has been associated with high procedural

Table 6.3 Survival with acute leukaemia

mortality. The development of peripheral rather than

bone marrow stem cell harvest has reduced procedural

Type

At 5 years

mortality.

Childhood acute lymphoblastic

65-75%

The principle of dose intensity suggests that higher

leukaemia

doses of chemotherapy will reduce relapse risk. Autologous

Adult acute lymphoblastic leukaemia

20-45%

transplantation involves stem cell rescue (with patients’

Acute myeloid leukaemia, aged

35-40%

own cells harvested in remission) after a potentially lethal

60 years

dose of chemotherapy. Ongoing large scale clinical trials are

Acute myeloid leukaemia, aged

10%

studying the benefit of this modality over conventional

60 years

treatment.

The concept of allogeneic transplantation—where healthy

stem cells from a sibling or unrelated donor are given to

replace diseased marrow—has always been appealing.

Realisation of a graft versus leukaemia (GVL) effect has

enhanced enthusiasm, though this effect is more pronounced

in chronic myeloid leukaemia. “Mini” allografts exploit GVL;

non-myeloablative doses of chemotherapy induce a state of

marrow chimaerism where persistent minimal residual disease

may be eradicated by donor lymphocyte infusion.

Patient selection for BMT remains a subject of

controversy. Some patients will self-exclude on personal,

age or health grounds. Others may be suitable for BMT

but not have an appropriate donor. This problem is likely to

worsen as family size reduces and volunteer healthy donors are

harder to attract.

The acute leukaemias

Novel developments

Box 6.6 Late effects of treatment for acute leukaemia

The majority of new presentations with acute leukaemia occur

• Cardiac: Arrhythmias, cardiomyopathy

in the older population. Whilst complete remission may be

• Pulmonary: Fibrosis

obtained with standard treatment in up to 62% of this group,

• Endocrine: Growth delay, hypothyroidism, gonadal

only 8-12% will be alive at five years. This phenomenon is due

dysfunction or failure, infertility

to the increased finding of adverse karyotype, chemoresistant

• Renal: Reduced glomerular filtration rate

phenotype, and disease evolution from myelodysplastic

• Psychological: Intellectual dysfunction, long term anxiety

syndrome together with comorbidity and poor tolerance of

about relapse

• Second malignancy: Secondary leukaemias or solid tumours

chemotherapy in this population. This, together with the

• Cataracts

knowledge that patients who relapse have three year survival

rates of 8%, has driven the search for alternative but potentially

synergistic modalities of treatment.

Gemtuzumab ozogamicin (GO) is a humanised

monoclonal antibody to CD33, an antigen found on

80% of

blasts in AML, conjugated to the anti-tumour antibiotic

calicheamicin. Patients treated in first relapse AML show 30%

complete remission with single agent GO and reasonable

toxicity profiles. This agent is being incorporated into the

latest AML studies.

STI 571 is a tyrosine kinase (TK) inhibitor which has good

activity in chronic myeloid leukaemia due to the presence of

the Philadelphia chromosome associated with aberrant TK

production. The Philadelphia chromosome is found in 20-30%

adult ALL and is associated with extremely poor prognosis.

STI may be of benefit in this group and also in those with

AML who show Flt 3 mutations, also associated with

aberrant TK.

Further reading

The multi-drug resistant genotype (MDR) results in patients

• Burnett A. Acute myeloid leukaemia Clin Haematol 2001;14(1).

phenotypically showing resistance to a spectrum of drugs by

• Kantarjian H, Hoelzer D, Larson R. Advances in the treatment of

causing them to efflux from cells before exerting their

acute lymphocytic leukaemia Hematol/Oncol Clin North Am

2000;14(6) and 2001;15(1).

cytotoxic effect. Inhibitory drugs to this process are in

• Gorin N. New developments in the therapy of acute myelocytic

advanced stages of development. A few of the many other fields

leukaemia. Am Soc Hematol Educ Progr 2000;69-89.

of development showing potential are anti-angiogenic drugs,

• Appelbaum F, Rowe J, Radich J, Dick J. Acute myeloid

anti-leukaemic vaccines and tumour-specific cytotoxic T cell

leukaemia. Am Soc Hematol Educ Progr 2001;62-86.

therapy. It is increasingly understood that acute leukaemia is a

• Hoelzer D, Burnett A. Acute leukaemias in adults. In Oxford

highly heterogeneous condition which requires an

textbook of oncology, 2nd edn. Oxford: Oxford University Press,

2002;2191-2212.

individualised approach to management.

Grimwade D, Walker H, Oliver F et al. on behalf of the Medical

•

Research Council Adult and Children’s Leukaemia Working

Parties. The importance of diagnostic cytogenetics on outcome

Toxicity of therapy

in AML: Analysis of 1,612 patients entered into the MRC AML10

trial Blood 1998;92(7):2322-33.

Early side effects

• Goldstone A, Burnett A, Wheatley K, Smith A, Hutchinson RM,

Most chemotherapeutic agents have pronounced side effects,

Clark RE on behalf of the Medical Research Council Adult

such as nausea and vomiting, mucositis, hair loss, neuropathy,

Leukaemia Working Party. Attempts to improve treatment

and renal and hepatic dysfunction. Many also cause

outcomes in AML in older patients: The results of the UK MRC

AML11 trial. Blood 2001;98(5):1302-11.

myelosuppression, resulting in profound neutropenia for two

• Yin J, Wheatley K, Rees J, Burnett A on behalf of the UK MRC

or more weeks with resultant opportunistic infection. Febrile

Adult Leukaemia Working Party. Comparison of ‘sequential’

neutropenic episodes require prompt use of broad spectrum

versus ‘standard’ chemotherapy as re-induction treatment, with

antibiotics. Many patients also develop fungal infection

or without cyclosporine, in refractory/relapsed AML: results of

requiring treatment with systemic antifungal drugs. Viral

the UK MRC AML-R trial. Br J Haematol 2001;113:713-26.

infection is predominantly seen in the post-transplant setting.

• Sievers E, Larson R, Stadtmauer E et al. for the Mylotarg Study

Group. Efficacy and safety of Mylotarg (gemtuzumab

ozogamicin) in patients with CD33-positive acute myeloid

Late effects

leukemia in first relapse. J Clin Oncol (in press).

All treatments for acute leukaemia can result in long term side

effects that may bring appreciable morbidity or even lead to

death. Patients must therefore be followed up in a specialist

unit for at least 10 years. Particular attention must be paid to

The interphase fluorescent in situ hybridisation was provided by

the long term problems with growth and endocrine function in

Brian Reeves and Helen Kempski, Department of Haematology,

children.

Great Ormond Street Hospital for Children NHS Trust, London.

Platelet disorders

R J Liesner, S J Machin

Platelets are produced predominantly by the bone marrow

The lifespan of a platelet is 7-10 days and the normal count

megakaryocytes as a result of budding of the cytoplasmic

for all ages is 150-450

10⁹/l

membrane. Megakaryocytes are derived from the haemopoetic

stem cell, which is stimulated to differentiate to mature

megakaryocytes under the influence of various cytokines,

including thrombopoietin. Once released from the bone

marrow young platelets are trapped in the spleen for up to 36

Normal platelet function

hours before entering the circulation, where they have a

Fibrinogen

primary haemostatic role. Their normal lifespan is 7-10 days

von Willebrand factor

and the normal platelet count for all age groups is

Dense granules contain ADP,ATP,5HT etc.

150-450

10⁹/l. The mean platelet diameter is 1-2

m and the

α granules contain fibrinogen, VWF, etc.

Platelet

GP IIb/IIIa

normal range for cell volume (MPV) is 8-11 fl. Although

platelets are non-nucleated cells, those that have recently been

released from the bone marrow contain RNA and are known as

reticulated platelets. They normally represent 8-16% of the

Platelet

total count and they indirectly indicate the state of marrow

production.

GP Ib/IX

Normal haemostasis

The platelet membrane has integral glycoproteins essential in

the initial events of adhesion and aggregation, leading to

Collagen fibres

Endothelial cell

formation of the platelet plug during haemostasis.

Glycoprotein receptors react with aggregating agents such

Figure 7.1

Normal platelet function

as collagen on the damaged vascular endothelial surface,

fibrinogen, and von Willebrand factor to facilitate platelet-

platelet and platelet-endothelial cell adhesion. The major

glycoproteins are the Ib-IX complex, whose main binding

protein is von Willebrand factor, and IIb/IIIa which specifically

binds fibrinogen. Storage organelles within the platelet include

the “dense” granules which contain nucleotides, calcium and

serotonin, and granules containing fibrinogen, von

Willebrand factor, platelet-derived growth factor and many

other clotting factors. Following adhesion, the platelets are

stimulated to release the contents of their granules essential for

platelet aggregation. The platelets also provide an extensive

phospholipid surface for the interaction and activation of

clotting factors in the coagulation pathway.

Congenital abnormalities

Congenital abnormalities of platelets can be divided into

disorders of platelet production and those of platelet function.

Figure 7.2

Amegakaryocytic thrombocytopenia with absent radii (TAR

All are very rare. In general they cause moderate to severe

syndrome)

bleeding problems.

Fanconi’s anaemia is an autosomal recessive preleukaemic

condition which often presents as thrombocytopenia with

skeletal or genitourinary abnormalities. The cardinal

laboratory feature is abnormal chromosomal fragility.

The condition can be cured with bone marrow

transplantation (BMT).

Thrombocytopenia with absent radii (TAR syndrome) presents

with the pathognomic sign of bilateral absent radii and with

severe (

10⁹/l) neonatal thrombocytopenia, though this

often improves after the first year of life. This should be

distinguished from amegakaryocytic thrombocytopenia, another

leukaemia predisposition syndrome, in which severe neonatal

thrombocytopenia is present with or without somatic

Figure 7.3 Giant granular platelets in peripheral blood film as seen in

abnormalities.

Bernard-Soulier syndrome or May Hegglin anomaly

Platelet disorders

The Wiskott-Aldrich syndrome is an X-linked disorder with a

triad of thrombocytopenia, eczema, and immunodeficiency.

The platelet count is usually 20-100

10⁹/l, and the platelets

are small and functionally abnormal. Like Fanconi’s anaemia,

this condition can only be cured with BMT.

May Hegglin anomaly and variants of Alport’s syndrome are

both characterised by giant platelets. The former is a benign

condition, but the latter is associated with progressive

hereditary nephritis and deafness.

Glanzmann’s thrombasthenia, the Bernard-Soulier syndrome and

platelet-type von Willebrand’s disease are characterised by absence

Figure 7.4 Bleeding around the eye in a

or abnormalities of platelet membrane glycoproteins resulting

patient with Bernard-Soulier syndrome

in defective platelet adhesion and aggregation.

In platelet storage pool diseases deficiencies in either the or

dense granules cause poor secondary platelet aggregation.

Box 7.1 Acquired disorders of reduced platelet

There are also a variety of further specific surface membrane

production due to bone marrow failure or replacement

defects and internal enzyme abnormalities, which although

• Drug induced

difficult to define, can cause troublesome chronic bleeding

• Leukaemia

• Metastatic tumour

problems.

•

Aplastic anaemia

•

Myelodysplasia

• Cytotoxic drugs

Acquired abnormalities

• Radiotherapy

• Associated with infection

Decreased production of platelets due to suppression or

• Megaloblastic anaemia

failure of the bone marrow is the commonest cause of

thrombocytopenia. In aplastic anaemia, leukaemia and marrow

infiltration, and after chemotherapy, thrombocytopenia is

Diseases of the platelet storage pool are deficiencies in

usually associated with a failure of red and white cell

either the or dense granules causing poor secondary

production but may be an isolated finding secondary to drug

platelet aggregation

toxicity (penicillamine, cotrimoxazole), alcohol, or viral

infection (HIV, infectious mononucleosis). Viral infection is

the most common cause of mild transient thrombocytopenia.

Increased platelet consumption may be due to immune or

non-immune mechanisms. Idiopathic thrombocytopenic purpura

(ITP) is a relatively common disorder and is the most frequent

cause of an isolated thrombocytopenia without anaemia or

neutropenia. In adults it often presents insidiously, most

frequently in women aged 15-50 years and can be associated

with other autoimmune diseases, in particular systemic lupus

erythematosus or the primary antiphospholipid syndrome.

In children the onset is more acute and often follows a viral

infection. The autoantibody produced is usually IgG, directed

against antigens on the platelet membrane. Antibody-coated

platelets are removed by the reticuloendothelial system,

reducing the life span of the platelet to a few hours. The

Figure 7.5 Spontaneous skin purpura in severe immune

platelet count can vary from

10⁹/l to near normal.

thrombocytopenia

The severity of bleeding is less than that seen with comparable

degrees of thrombocytopenia in bone marrow failure due to

the predominance of young, larger, and functionally superior

platelets.

Post-transfusion purpura (PTP) is a rare complication of blood

transfusion. It presents with severe thrombocytopenia 7-10 days

after the transfusion and usually occurs in multiparous women

who are negative for the human platelet antigen 1a (HPA1a).

Antibodies to HPA1a develop, and in some way this

alloantibody is responsible for the immune destruction of

autologous platelets.

Neonatal alloimmune thrombocytopenia (NAITP) is similar to

haemolytic disease of the newborn except that the antigenic

stimulus comes from platelet specific antigens rather than red

cell antigens. In 80% of cases the antigen is human platelet

antigen 1a, and mothers negative (about 5% of the population)

for this antigen form antibodies when sensitised by a fetus

positive for the antigen. Fetal platelet destruction results from

transplacental passage of these antibodies and severe bleeding,

Figure 7.6 Bone marrow aspirate showing increased megakaryocytes in

including intracranial haemorrhage, can occur in utero.

immune thrombocytopenia

ABC of Clinical Haematology

Firstborns are frequently affected and successive pregnancies

are equally or more affected.

Heparin-induced thrombocytopenia (HIT) occurs during

unfractionated heparin therapy in up to 5% of patients, but is

less frequently associated with low molecular weight heparins. It

may become manifest when arterial or venous thrombosis

occurs during a fall in the platelet count and is thought to be

due to the formation of antibodies to heparin that are bound

to platelet factor 4, a platelet granule protein. The immune

complexes activate platelets and endothelial cells, resulting in

thrombocytopenia and thrombosis coexisting. Heparin-induced

thrombocytopenia carries an appreciable mortality risk if the

diagnosis is delayed.

Figure 7.7 Red cell fragmentation in patient who presented with

confusion and lethargy in whom thrombotic thrombocytopenic purpura

In thrombotic thrombocytopenic purpura (TTP) the presenting

was diagnosed. She responded well to large volume plasma exchange for

features can be fever, fluctuating neurological signs, renal

one week

impairment, and intravascular haemolysis, resulting in

thrombocytopenia. Recent evidence suggests that the condition

is caused by an autoantibody to a protease enzyme which is

Box 7.2 Post-transfusion purpura

responsible for cleaving the ultra-high molecular weight

• This is an acquired abnormality

multimers of von Willebrand factor. The development of this

• It is a rare complication of blood transfusion presenting

antibody causes a circulating excess of highly active multimers,

with severe thrombocytopenia 7-10 days after the transfusion

causing intravascular platelet agglutination in vivo and the

• Patients are usually multiparous women who are negative

precipitation of a microangiopathic haemolytic anaemia. The

for the human platelet antigen 1a

condition is suspected clinically by thrombocytopenia, red cell

• Antibodies to this antigen develop that are somehow

fragmentation on the blood film, and a reticulocytosis. The

responsible for the immune destruction of the patient’s own

platelets

demonstration of an abnormal pattern of von Willebrand

multimers will make the diagnosis highly likely and the

complete absence of the cleaving protease caused by an

inhibitory antibody can be proved in some specialised

Box 7.3 Causes of acquired platelet dysfunction

laboratories.

• Aspirin and non-steroidal anti-inflammatory agents

Disseminated intravascular coagulation usually occurs in

• Penicillins and cephalosporins

critically ill patients as a result of catastrophic activation of the

• Uraemia

coagulation pathway, often due to sepsis. Widespread platelet

• Alcohol

consumption occurs causing thrombocytopenia.

• Liver disease

The spleen normally pools about a third of the platelet

• Myeloproliferative disorders

mass, but in massive splenomegaly this can increase up to 90%,

• Myeloma

• Cardiopulmonary bypass

resulting in apparent thrombocytopenia.

• Fish oils

Aspirin, non-steroidal anti-inflammatory agents, and glycoprotein

IIb/IIIa antagonists are the most common cause of acquired

platelet dysfunction. For this reason aspirin and the IIb/IIIa

antagonists are used therapeutically as antiplatelet agents.

Box 7.4 Disorders with increased consumption of

Aspirin acts by irreversibly inhibiting cyclo-oxygenase activity in

platelets

the platelet, resulting in impairment of the granule release

• Disorders with immune mechanism

reaction and defective aggregation. The effects of a single dose

Autoimmune: idiopathic thrombocytopenic purpura

of aspirin last for the lifetime of the platelet (7-10 days).

Alloimmune: post-transfusion purpura, neonatal

Clopidogrel, a thienopyridine derivative, has now been

alloimmune thrombocytopenia

introduced as an oral antiplatelet agent which inhibits ADP

Infection associated: infectious mononucleosis, HIV,

malaria

binding to the platelet membrane and is useful in patients who

Drug induced: heparin, penicillin, quinine,

are intolerant or resistant to aspirin. It is becoming widely used

sulphonamides, rifampicin

as a prophylactic agent for myocardial ischaemia and related

• Thrombotic thrombocytopenic purpura/haemolytic

coronary syndromes.

uraemic syndrome

Bleeding in uraemic patients is most commonly from defects in

• Hypersplenism and splenomegaly

platelet adhesion or aggregation, though thrombocytopenia,

• Disseminated intravascular coagulation

• Massive transfusion

severe anaemia with packed cell volume

20% or coagulation

defects can also contribute.

In essential (primary) thrombocytosis (ET) and reactive

(secondary) thrombocytosis the platelet count is raised above the

Box 7.5 Thrombocytosis

upper limit of normal. A wide range of disorders can cause a

• Essential (primary) thrombocytosis

raised platelet count (

800

10⁹/l), but patients are normally

• Reactive (secondary) thrombocytosis

asymptomatic, except in ET, when excessive spontaneous

Infection

bleeding may develop when the count exceeds 1000

10⁹/l.

Malignant disease

Antiplatelet drugs can be useful to prevent thrombosis in high

Acute and chronic inflammatory diseases

risk patients, for example, postoperatively. Some

Pregnancy

After splenectomy

myelodysplastic syndromes may be complicated by an acquired

Iron deficiency

storage pool type platelet disorder.

Haemorrhage

Platelet disorders

History and examination of patients

Full blood count and blood film

Abnormal bleeding associated with thrombocytopenia or

abnormal platelet function is characterised by spontaneous skin

purpura and ecchymoses, mucous membrane bleeding and

Normal platelet count

Low platelet count

protracted bleeding after trauma. Prolonged nose bleeds can

occur, particularly in children, and menorrhagia or postpartum

In vitro bleeding time

Monospot and viral serology

haemorrhage is common in women. Rarely, subconjunctival,

Platelet aggregation and nucleotides

Bone marrow aspirate/trephine

Flow cytometry

Platelet-associated antibodies

retinal, gastrointestinal, genitourinary or intracranial bleeds

Screening for von Willebrand's

Fibrin degradation products

may occur. In thrombocytopenic patients severe spontaneous

disease and analysis of

Reticulocyte count

bleeding is unusual with a platelet count

10⁹/l.

multimeric pattern

Autoantibody screening

Platelet serology

Heparin-platelet factor 4 antibody test

Screening for Fanconi's anaemia

Investigations

The investigations in a suspected platelet disorder will depend

Figure 7.8 Investigation of suspected platelet disorder

on the presentation and history in each patient. If the bleeding

is severe the patient may need urgent hospital referral for

prompt evaluation, diagnosis, and treatment, which may entail

blood product support. All patients should have a full blood

count, blood film, coagulation, and biochemical screen,

followed by further investigations depending on the results of

these.

Thrombocytopenia can be artefactual and due to platelet

clumping or a blood clot in the sample, which should be

excluded in all cases. The skin bleeding time, which is invasive,

variable and not reliable in screening mild platelet disorders,

has been replaced by devices which perform an in vitro

bleeding time on small volumes of citrated blood and simulate

platelet function in a high shear rate situation. The sensitivity

of these devices for all platelet disorders is still under

investigation.

A neonate or small infant with bleeding must be referred

for evaluation as the inherited bleeding disorders (eg

Management

haemophilia or von Willebrand’s disease) and platelet

disorders may present at a very young age

All serious bleeding due to a platelet disorder needs

haematological assessment and treatment. Mild or trivial

bleeding due to a transient postviral thrombocytopenia or

Box 7.6 Treatment of platelet disorders

aspirin ingestion needs no active treatment and can be

Congenital disorders

managed in the community.

• Platelet transfusions (leucodepleted, HLA compatible and

irradiated)

Congenital disorders

• DDAVP

• Tranexamic acid

A neonate or small infant with bleeding must be referred for

• Recombinant factor VIIa

evaluation as the inherited bleeding disorders (eg haemophilia

• Bone marrow transplantation

or von Willebrand’s disease) and platelet disorders can present

Acquired disorders

at a very young age.

• Bone marrow failure

Bleeding episodes in all the congenital thrombocytopenias

Platelet transfusions if platelet count

10⁹/l

and platelet function disorders require filtered HLA-compatible

• Idiopathic thrombocytopenic purpura (adults)

platelet transfusions to secure haemostasis, though in minor

Prednisolone

episodes in the dysfunctional syndromes desmopressin

Intravenous immunoglobulin

Splenectomy

(DDAVP) given intravenously or intranasally with anti-

• Post-transfusion purpura

fibrinolytics (tranexamic acid) may be sufficient. There is

Intravenous immunoglobulin

increasing evidence that in selected patients with congenital

Plasma exchange

disorders recombinant factor VIIa may be of use in the

• Heparin-induced thrombocytopenia

treatment or prevention of bleeding. This avoids exposure to

Anticoagulation but without heparin

blood products but is expensive. Bone marrow transplantation

• Thrombotic thrombocytopenic purpura

Large volume plasma exchange

can potentially offer a cure in a number of these conditions.

Aspirin when platelets

10⁹/l

• Disseminated intravascular coagulation

Acquired disorders

Treat underlying cause

In thrombocytopenia due to bone marrow failure or marrow

Fresh frozen plasma

infiltration—for example leukaemia or cancer—prophylactic

Platelet transfusion

platelet transfusions are given to keep the platelet count above

• Hypersplenism

Splenectomy if severe

10⁹/l though the threshold is higher in infected or

• Platelet function disorders

bleeding patients or to cover invasive procedures.

Platelet transfusion

In childhood idiopathic thrombocytopenic purpura

DDAVP (occasionally of use; for example in uraemia)

spontaneous recovery is common, and treatment is given only

ABC of Clinical Haematology

in life-threatening bleeding. In adults the condition rarely

With disseminated intravascular coagulation it is essential to

remits without treatment and is more likely to become chronic.

treat the underlying cause as well as support depletion of

Initial treatment is prednisolone 1 mg/kg daily (80% of cases

clotting factors and platelets with blood products.

remit) or intravenous immunoglobulin (0.4 g/kg for five days

In pronounced bleeding or risk of bleeding due to the

or 1 g/kg for two days), or both combined. In refractory

acquired disorders of platelet function, platelets usually have to

patients splenectomy has a 60-70% chance of long term cure

be transfused to provide normally functioning platelets, though

and azathioprine, danazol, vinca alkaloids and high dose

desmopressin (DDAVP) and tranexamic acid can also be of

dexamethasone have all been tried with variable success. Post-

value. Usually treatment may only be necessary to cover surgical

transfusion purpura may respond to intravenous

procedures or major haemorrhage.

immunoglobulin (at doses given above), or plasma exchange

may be required. Platelet transfusions should be avoided.

Patients in whom heparin-induced thrombocytopenia is

Further reading

suspected are often inpatients with ongoing thrombosis and

• Coller BS. Anti-GPIIb/IIIa drugs: current strategies and future

may have complex medical problems. It is essential to withdraw

directions. Thromb Haemostas 2001;86:427-43.

heparin and treat thrombosis with other anticoagulants,

• Hardistry RM. Platelet functional disorders. In: Lilleyman J,

Hann I, Blanchette V, eds. Pediatric hematology, 2nd edn.

avoiding all forms of heparin. Warfarin, synthetic heparinoids

Edinburgh: Churchill Livingstone, 2000.

or ancrod can be used. Platelet transfusions are contraindicated

• Rendu F, Brohard-Bohn B. The platelet release reaction:

in heparin-induced thrombocytopenia and in thrombotic

granules’ constituents, secretion and functions. Platelets

thrombocytopenic purpura. If the latter is suspected clinically

2001;12:261-73.

and on the basis of laboratory tests, large volume plasma

• Shapiro AD. Platelet function disorders. Haemophilia 2000;6:

exchange should be started immediately and continued daily

120-7.

• Smith OP. Inherited and congenital thrombocytopenia. In:

until there is substantial clinical improvement, and all the

Lilleyman J, Hann I, Blanchette V, eds. Pediatric hematology, 2nd

results of haematological tests have normalised. Aspirin can be

edn. Edinburgh: Churchill Livingstone, 2000.

started once the platelet count is

10⁹/l.

The myelodysplastic syndromes

David G Oscier

The term myelodysplastic syndromes was introduced in 1975 by

a group of French, American, and British haematologists (FAB

Age specific incidence rates

group) to describe a group of disorders with characteristic

(per 100 000 cases)

abnormalities of peripheral blood and bone marrow

<50

0.5

morphology and impaired bone marrow function, which tend

50-59

5.3

60-69

to evolve into acute myeloid leukaemia. Although the

70-79

myelodysplastic syndromes may occur at any age, they are

>80

predominantly diseases of elderly people.

Aetiology and pathogenesis

Primary myelodysplastic syndrome describes those cases—the

majority—in which the cause is unknown. Case-control studies

>20

>25 >30 >35 >40 >45 >50 >55 >60 >65 >70 >75 >80 >85 >90 >95

have shown a modest correlation between the myelodysplastic

Age (in 5 year blocks)

syndromes and exposure to low doses of radiation and organic

chemicals.

Figure 8.1 Age distribution and incidence rates per 1 000 000 population

Therapy-related myelodysplastic syndrome, sometimes called

of patients presenting with myelodysplastic syndrome in Bournemouth,

1981-90

secondary myelodysplastic syndrome, describes cases that have

arisen as a long term complication of cytotoxic chemotherapy,

radiotherapy and particularly following autologous

transplantation for lymphoma. The risk is highest 4-10 years

after treatment with alkylating agents, such as chlorambucil and

cyclophosphamide.

The hypothesis that patients who develop myelodysplastic

Inherited

syndrome following chemotherapy or exposure to

DNA damage

Myeloid stem cell

environmental toxins may have inherited an impaired ability to

Acquired

metabolise and detoxify potential carcinogens or repair DNA

damage is currently being investigated.

Myelodysplastic clone

The combination of peripheral blood cytopenias and a

Increased apoptosis

hypercellular bone marrow found in the majority of patients

with myelodysplastic syndromes can be explained by an

Abnormal marrow

Immune damage

Microenvironment

increased susceptibility to apoptosis (programmed cell death)

of bone marrow precursor cells. Immune mediated T cell

Increased angiogenesis

myelosuppression results in marrow hypocellularity in the

Myelodysplastic syndrome

remaining 10-20% of patients.

Secondary genetic

and epigenetic

abnormalities

Diagnosis

Patients present with the features of bone marrow failure—

Acute myeloid leukaemia

namely, symptoms of anaemia, bacterial infections, and

bleeding or bruising. Splenomegaly is present in about 10% of

Figure 8.2 Pathogenesis of myelodysplastic syndrome

patients, particularly in chronic myelomonocytic leukaemia,

one subtype of the myelodysplastic syndromes. Increasingly,

myelodysplastic syndrome is an incidental finding in elderly

patients whose routine blood count shows an unexplained

anaemia, macrocytosis, neutropenia, monocytosis, or

thrombocytopenia.

The myelodysplastic syndromes can be diagnosed only by a

haematologist, primarily on the basis of characteristic full blood

count indices, morphological abnormalities on the peripheral

blood film, and characteristic bone marrow appearances.

Although myelodysplastic syndrome may sometimes be

diagnosed on the basis of a blood film alone, a bone marrow

aspirate and trephine are necessary to make a confident

diagnosis and to assess the severity of the disease. Marrow

examination can safely be omitted only in elderly, infirm

patients with mild cytopenias who would not need treatment

Figure 8.3 Blood film showing normal neutrophil (left) and dysplastic

regardless of the marrow findings.

neutrophil with granular cytoplasm and hypolobated nucleus

ABC of Clinical Haematology

Diagnosis is frequently straightforward, particularly if

Table 8.1 Morphological abnormalities in myelodysplastic

morphological abnormalities are found in the three major

syndrome

lineages—erythroid (red cells), myeloid (granulocytes, including

neutrophils), and megakaryocytic series (platelets)—in the

Lineage

Blood

Marrow

clinical context of an elderly patient with a peripheral blood

Erythroid

Oval macrocytes

Abnormal nuclear

cytopenia. However, morphological dysplasia is not synonymous

shape and chromatin

chromatin pattern

with myelodysplastic syndrome, and similar morphological

Basophilic stippling

Ring sideroblasts

abnormalities to those found in early myelodysplastic syndromes

Myeloid

Hypogranular

may be seen in vitamin B₁₂ deficiency or folate deficiency,

neutrophils

alcohol excess, after cytotoxic chemotherapy, HIV infection, and

Hypolobated

even in a minority of cells in the bone marrow of normal

neutrophil nuclei

individuals. Problems also arise if morphological abnormalities

Megakaryocytic

Agranular platelets

Micromegakaryocytes

are subtle, if they involve only one cell lineage, or if the staining

Mononuclear

of blood and marrow slides is suboptimal.

megakaryocytes

Megakaryocytes with

separated nuclei

Chromosome analysis

Cytogenetic analysis should be performed in all cases in which

bone marrow examination is indicated. It is valuable both

prognostically and when the morphological diagnosis is

difficult. A clonal chromosome abnormality—that is, the same

abnormality appearing in more than one cell—confirms the

presence of a primary bone marrow disorder and excludes the

reactive causes of dysplasia listed above. Chromosomal

abnormalities are found in 30-50% of cases of primary

myelodysplastic syndrome and in 80% of cases of therapy-

related myelodysplastic syndrome. Specific chromosomal

abnormalities may be associated with particular clinical and

(a)

haematological features. For example, loss of part of a long

arm (“q”) of chromosome 5 occurring as the only

chromosomal abnormality (5q- syndrome) is associated with

macrocytic anaemia in elderly women and a low risk of

transformation to acute myeloid leukaemia. Loss of the short

arm (“p”) of chromosome 17 is found in advanced disease and

is associated with drug resistance and short survival.

The recent introduction of new and more powerful

techniques to detect genetic abnormalities and study both gene

(b)

and protein expression should lead to the identification of the

key genetic events which initiate myelodysplastic syndromes

and result in disease progression and evolution to acute

leukaemia.

Table 8.2 Chromosome abnormalities in myelodysplasia

Incidence(%)

Primary

Therapy related

(c)

myelodysplastic

Figure 8.4

Abnormal megakaryocytes: (a) large mononuclear

Abnormality

syndrome

megakaryocyte; (b)micro megakaryocytes; (c) large polypoid

megakaryocyte

Deletion of 5q

10-20

Monosomy 7

10-15

30-50

Trisomy 8

Loss of 17p

Classification

In 1982 the FAB group divided the myelodysplastic syndromes

into five subgroups based on (a) the percentage of immature

myeloid cells (blast cells) and ring sideroblasts (immature red

cells with iron granules arranged in a ring around the nucleus)

in the bone marrow and (b) the presence or absence of

a raised peripheral blood monocyte count. This classification

was rapidly adopted worldwide and had prognostic significance.

The World Health Organization (WHO) has now proposed

The myelodysplastic syndromes

Table 8.3 FAB classification of myelodysplastic syndrome

Table 8.4 WHO classification of myelodysplastic syndrome

Median survival

Further reading

factor (G-CSF) induces a transient neutrophilia in the majority

• Bunning RD, Bennet JM, Flandrin G et al. Myelodysplastic

of cases but long term intermittent G-CSF should only be

syndromes. In: Jaffe ES et al., eds. WHO classification of tumours.

considered for patients with severe neutropenia and recurrent

Lyon: IARC Press, 2001.

• Emanuel PD. Myelodysplasia and myelopreoliferative disorders

infections. Erythropoietin can raise the haemoglobin and

in childhood: an update. Br J Haematol 1999;105:852-63.

improve quality of life in some patients with myelodysplastic

• Germing U, Gattermann N, Strupp C et al. Validation of WHO

syndromes with

10% of bone marrow blasts. The addition of

proposals for a new classification of primary myelodysplastic

G-CSF improves the response rate, particularly in patients with

syndromes: a retrospective analysis of 1600 patients. Leukaemia

ring sideroblasts. Response rates of 70% are achievable in

Res 2000;24:983-92.

patients with low basal erythropoietin levels and a transfusion

• Hellstrom-Lindberg E, Negrin R, Stein R et al. Erythroid

response to treatment with G-CSF plus erythropoietin for the

requirement of

2 units per month. Growth factors are

anaemia of patients with myelodysplastic syndromes: proposal for

expensive, however, and the least effective in patients with

a predictive model. Br J Haematol 1997;99:344-51.

advanced disease and severe cytopenias—those who most

• Molldrem J, Caples M, Mavroudis D et al. Antithymocyte globulin

require treatment.

for patients with myelodysplastic syndrome. Br J Haematol

1997;99:699-705.

• Pedersen-Bjergaard J, Andersen M, Christiansen D. Therapy-

related acute myeloid leukaemia and myelodysplasia after high

dose chemotherapy and autologous stem cell transplantation.

Blood 2000;95:3273-9.

The histogram showing age distribution and incidence rates for

• Witte T, Suciu S, Verhoef G et al. Intensive chemotherapy

myelodysplastic syndrome is adapted with permission from the

followed by allogeneic or autologous stem cell transplantation

British Journal of Haematology (Williamson PJ, Kruger AR,

for patients with myelodysplastic syndromes (MDSs) and acute

Reynolds PJ, Hamblin TJ, Oscier DG. Establishing the incidence of

myeloid leukaemia following MDS. Blood 2001;98:2326-31.

myelodysplastic syndrome. 1994;87:743-5).

Multiple myeloma and related conditions

Charles R J Singer

A heterogeneous group of conditions are associated with

Box 9.1 Conditions associated with M proteins

monoclonal immunoglobulin (M protein or paraprotein) in

Stable production

the serum or urine and are characterised by disordered

• Monoclonal gammopathy of undetermined significance

proliferation of monoclonal lymphocytes or plasma cells. The

• Smouldering multiple myeloma

clinical phenotype of each condition is determined by the rate

Progressive production

of accumulation, site and biological properties of the abnormal

• Multiple myeloma (IgG, IgA, free light chains, IgD, IgE,

cells and also by the biological properties of the monoclonal

non-secretory, IgM)

protein.

• Plasma cell leukaemia

• Solitary plasmacytoma of bone

•

Extramedullary plasmacytoma

• Waldenström’s macroglobulinaemia (IgM)

Multiple myeloma

• Chronic lymphocytic leukaemia

• Malignant lymphoma

The incidence of myeloma is about 4 per 100 000 in Britain. It

• Primary amyloidosis

occurs more than twice as frequently in African Americans than

• Heavy chain disease

in white Americans and Europeans, although it is much less

common among Chinese and Japanese Asians. Myeloma is

extremely rare in people aged under 40 years, but its incidence

increases to over 30 per 100 000 in those aged over 80. The

median age at diagnosis is 69 years, with slight male

Box 9.2 Clinical features of myeloma

predominance.

Common

• Bone pain and pathological fractures

Pathogenesis and clinical features

• Anaemia and bone marrow failure

Myeloma is a tumour of monoclonal plasma cells that

• Infection due to immune paresis and neutropenia

accumulate in the marrow, leading to anaemia, bone marrow

• Renal impairment

failure and bone destruction. Immunoglobulin heavy chain

Less common

analysis reveals that the tumour arises in a post-germinal centre

• Acute hypercalcaemia

B lymphocyte. This probably occurs in a lymph node or in the

• Symptomatic hyperviscosity

spleen and neoplastic cells home to the bone marrow, where

• Neuropathy

• Amyloidosis

the environment stimulates proliferation of plasma cells.

• Coagulopathy

Most myeloma cells produce and secrete a monoclonal

protein, usually intact immunoglobulin. IgG paraprotein is

present in 60% of cases and IgA in 20-25%, and in 15-20% of

cases free immunoglobulin light chains alone are produced.

Myeloma in which the cells secrete IgD, two clonal proteins,

IgM, or no protein at all are rare. Free light chains are

detectable in urine as Bence Jones protein.

Accumulation of M protein may lead to hyperviscosity

(especially IgA and IgM due to the size of the Ig molecule) or

deposition of the protein in renal tubules, resulting in renal

failure. Production of normal immunoglobulin is often

depressed (immune paresis) and contributes to the patient’s

susceptibility to infection.

Bone destruction is a characteristic feature of myeloma, and

the associated bone pain is a major cause of morbidity in

myeloma. Myeloma is associated with abnormal bone

remodelling due to increased osteoclastic bone resorption and

inhibition of osteoblastic bone formation. This results in

pronounced bone loss and the characteristic osteolytic lesions

predisposing to pathological fractures. Widespread bone

destruction may lead to hypercalcaemia, resulting in a vicious

cycle of dehydration, worsening hypercalcaemia, and renal

failure.

Interactions between marrow stroma cells (including

osteoclasts) and myeloma cells play a critical role in myeloma

cell proliferation and the development of bone disease. Stroma

cells produce interleukin-6, a growth factor for myeloma cells,

which in turn produce tumour necrosis factor and

interleukin-1 . These stimulate stroma cell production of

RANK-L (receptor activator of NF -B ligand). Binding of

Figure 9.1 Radiograph showing multiple lytic lesions and pathological

fractures of humerus

RANK-L to its receptor (RANK) expressed by osteoclast

ABC of Clinical Haematology

Plasma cell

OPG

Osteoclast

precursor

RANK-L

Osteoblast

Osteoclast

Figure 9.3 Protein electrophoresis strip showing (1) normal plasma,

(2) polyclonal hypergammaglobulinaemia, (3) serum M protein, and

(4) urine M protein (Bence Jones proteinuria) and albuminuria

RANK-L = receptor activator of nuclear factor KB ligand (or TRANCE = TNF receptor

activation induced cytokine)

OPG = osteoprotogerin

Figure 9.2 Osteoclast activation by myeloma cells

precursors, promotes osteoclast proliferation and

differentiation. Osteoprotogerin (OPG) is also produced by

stroma cells, notably osteoblasts, which in experimental systems

inhibits RANK-L binding and osteoclast formation. Osteoblasts

are inhibited and secretion of OPG is reduced in myeloma.

Complex cytogenetic abnormalities are frequently found in

myeloma using modern techniques. These most commonly

involve chromosome 14q which is the site of the

Figure 9.4 Bone marrow aspirate showing infiltrate of abnormal plasma

immunoglobulin heavy chain gene and deletions of

cells (medium power)

chromosome 13 which confers an unfavourable prognosis.

The most common presenting complaint is bone pain

(60%), commonly affecting the back. Symptoms of anaemia,

renal failure, or infection are also frequent. Less common are

Box 9.4 Investigation of patients with suspected

symptoms of hyperviscosity (somnolence, impaired vision,

myeloma

purpura, and haemorrhage), acute hypercalcaemia, spinal cord

Useful screening tests

compression, neuropathy, or amyloidosis. About 20% of

• Full blood count and film: anaemia often present; film may

show rouleaux

patients are asymptomatic and detected through an elevated

• ESR or plasma viscosity: raised in the presence of a serum

ESR or elevated globulin.

paraprotein

• Urea and creatinine: may indicate renal impairment

Investigations and diagnosis

• Calcium, phosphate, alkaline phosphatase, and albumin:

Myeloma should be suspected in anyone aged over 40 years

may reveal hypercalcaemia or low albumin

with unexplained bone pain or fractures, osteoporosis,

• Serum immunoglobulins: to detect immuneparesis

osteolytic lesions, lethargy, anaemia, red cell rouleaux, raised

• Serum protein electrophoresis: to detect paraprotein

• Routine urinalysis: to detect proteinuria

erythrocyte sedimentation rate or plasma viscosity,

• Urine electrophoresis for BJP: to detect paraprotein

hypercalcaemia, renal dysfunction, proteinuria, or recurrent

• X-ray of sites of bone pain: may reveal pathological fracture

infection. It is characterised by the triad of bone marrow

or lytic lesion(s)

plasmacytosis, lytic bone lesions on skeletal radiology, and the

Diagnostic tests

presence of M protein in the serum or urine or both. Not all

• Bone marrow aspirate: to identify plasma cell infiltration

patients have all these features and minimal diagnostic criteria

• Skeletal survey: to identify lytic bone lesions not already

have been established to assist with difficult cases.

detected

• Paraprotein typing and quantification: to characterise

History and examination should be followed by a full blood

paraprotein

count and film; erythrocyte sedimentation rate or plasma

Tests to establish tumour burden and prognosis

viscosity; urea and creatinine concentrations; calcium,

• Serum beta-2-microglobulin: measure of tumour load

phosphate, and alkaline phosphatase concentrations; uric acid

• Serum C reactive protein: surrogate measure of IL-6

• Serum LDH: measure of tumour burden

• Serum albumin: when low reflects poor prognosis

Box 9.3 Minimal diagnostic criteria for myeloma

• Cytogenetics: prognostic value

•

10% plasma cells in bone marrow or plasmacytoma on

Tests that may be useful in some patients

biopsy

• Creatinine clearance and 24 hour proteinuria

• Clinical features of myeloma

• MRI : not routine but useful in patients with cord

• Plus at least one of:

compression or solitary plasmacytoma and abnormal in 30%

Serum paraprotein (IgG

30 g/l; IgA

20 g/l)

of patients with normal skeletal survey

Urine paraprotein (Bence Jones proteinuria)

• CT : where clinically indicated

Osteolytic lesions on skeletal survey

• Biopsy for amyloid and SAP scan: where suspected

Multiple myeloma and related conditions

concentration; serum protein electrophoresis; measurement of

Box 9.5 Laboratory findings at diagnosis (proportion

serum immunoglobulins; routine urine analysis; urine

of cases)

electrophoresis for Bence Jones protein; skeletal survey; and

• Normochromic normocytic anaemia

60%

bone marrow aspirate and biopsy.

• Increased erythrocyte sedimentation rate or

Normochromic normocytic anaemia is often present;

plasma viscosity

90%

neutropenia and thrombocytopenia suggest advanced disease.

• Serum M protein

80%

Rouleaux are usually seen in the blood film, and plasma cells

• Urine M protein only

20%

may also be present in about 5% of cases. The erythrocyte

• Raised serum calcium concentration

20%

sedimentation rate and plasma viscosity are often increased but

• Raised serum creatinine concentration

25%

• Proteinuria

70%

are normal in 10% of cases. The serum calcium concentration

is increased in up to 20% of cases. Serum alkaline phosphatase

concentration is invariably normal, reflecting suppressed

osteoblast activity. Raised urea and creatinine concentrations

occur in 20% of case and renal impairment, usually due to cast

nephropathy, is common. Low serum albumin concentration

reflects advanced disease. Serum beta-2-microglobulin and

C-reactive protein may be used to provide a prognostic index.

Skeletal radiology is a critical investigation and shows lytic

lesions, pathological fracture or generalised bone rarefaction in

80% of cases. Only osteoporosis is seen in 5-10%. Bone scans

are typically negative in multiple myeloma despite extensive

bone damage and are of no value. Magnetic resonance imaging

(MRI) is the most sensitive imaging technique for myeloma and

is valuable in suspected cord compression. Although not

routine it is useful in selected patients.

Approximately 10% of patients develop primary amyloid

which causes nephrotic syndrome, renal and cardiac failure,

and neuropathies. The extent of amyloid deposition can be

assessed using serum amyloid P component (SAP) scanning

procedures.

The most important differential diagnosis is between

multiple myeloma and monoclonal gammopathy of

undetermined significance for which no treatment is indicated.

No single test differentiates the two conditions reliably.

A serum IgG concentration

30g/l or IgA concentration

20g/l suggests a diagnosis of myeloma rather than

monoclonal gammopathy of undetermined significance. The

term “smouldering multiple myeloma” has been used for

patients in whom M protein and bone marrow criteria exist for

the diagnosis of myeloma, but anaemia, renal impairment, and

skeletal lesions do not develop and crucially, the M protein and

plasma cells remain stable. Here too a “watch and wait” policy is

appropriate.

Figure 9.5

MRI showing collapse of second cervical vertebra and

Several prognostic features have been recognised. Deletion

narrowing of spinal canal

of chromosome 13q is an important adverse feature. Renal

impairment is a risk factor due to its association with a high

tumour burden.

Management and clinical course

Without treatment, a patient with multiple myeloma is likely to

experience progressive bone damage, anaemia and renal

failure. Initial management should prioritise general aspects of

care.

Infection is the most common cause of death. Initial

treatment should consist of (a) adequate analgesia—opiates

Box 9.6 Features of poor prognosis at diagnosis

often, and local radiotherapy to fractures or osteolytic lesions

may have dramatic benefit; (b) rehydration—patients are often

• Low haemoglobin concentration (

85 g/l)

• Hypercalcaemia

dehydrated at presentation, even without hypercalcaemia or

• Advanced lytic bone lesions

renal impairment; (c) management of hypercalcaemia if

• High M protein production rates (IgG

70 g/l; IgA

50 g/l;

present—rehydration, diuresis, and bisphosphonate therapy;

Bence Jones protein

12 g/24 h)

(d) management of renal impairment—rehydration and

• Abnormal renal function

treatment of any hypercalcaemia often have a pronounced

• High plasma cell proliferative index

effect on abnormal serum chemistry in myeloma, though in

• Low serum albumin concentration (

30 g/l)

• High beta-2-microglobulin concentration (

6 mg/ml)

some patients plasmapheresis and chemotherapy alone or with

• High CRP

dialysis is effective; (e) treatment of infection—most infections

• 13q deletion

at diagnosis are bacterial and respiratory and respond to broad

ABC of Clinical Haematology

spectrum antibiotics, though later in the disease antifungal

Box 9.7 General aspects of care

treatment may be necessary; and (f ) chemotherapy.

• Pain control

Oral melphalan and prednisolone administered for 4 days

Analgesia (caution with NSAIDs)

at intervals of 4-6 weeks produces

50% reduction in the

Local radiotherapy

M protein concentration in 50% of patients. The treatment is

• Limitation of renal damage

well tolerated, but complete responses are rare and maximal

Good fluid intake

response generally requires 12 months of treatment. Most

Caution with nephrotoxic drugs including NSAIDs

patients achieve a “plateau phase” where the M protein remains

Rapid treatment of hypercalcaemia

• Hypercalcaemia

stable despite further therapy and continues to do so for a

Rehydration

median period of 12-18 months after chemotherapy stops. The

Intravenous bisphosphonate

median survival is about three years. During plateau phase

• Bone disease

clinical and laboratory results should be reviewed at regular

Local radiotherapy

intervals to identify progression at the earliest opportunity.

Long term bisphosphonates

Further treatment with melphalan may induce another plateau

Fixation of potential fractures

phase if a durable first plateau has been achieved. This

• Cord compression

MRI scanning to localise lesions

treatment approach is widely used for patients over 65. Weekly

Local radiotherapy

cyclophosphamide is tolerated by almost all patients, including

• Anaemia

the few who fail to tolerate melphalan.

Blood transfusion

Combination intravenous chemotherapeutic regimens may

Erythropoietin

produce higher response rates (up to 70%) and may improve

• Infection

survival. Combination regimens may be more effective in

Vigorous antibiotic therapy

Annual influenza vaccination

younger patients with high tumour loads, though they may be

• Hyperviscosity syndrome

more toxic in elderly patients. The VAD combination

Plasmapheresis

(vincristine, doxorubicin and dexamethasone) produces a high

Prompt chemotherapy

response rate (80%), is well tolerated in renal impairment,

requires 4-6 months of treatment to achieve maximum response

and produces a higher proportion of complete responses (up to

20%). This treatment is less toxic to haemopoietic progenitors

than standard melphalan treatment or other alkylator-

containing regimens and is therefore more widely used in

patients under 65 in whom autologous stem cell collection is

Box 9.8 Options for initial chemotherapy in myeloma

planned.

• Melphalan with or without prednisolone

High dose melphalan and autologous stem cell

• Infusional chemotherapy—vincristine and adriamycin

transplantation after initial treatment with VAD produces a

infusion plus either dexamethasone or methylprednisolone

complete response in up to 75% of patients and prolongs

• Combination therapy—for example, adriamycin,

survival but is not curative. It is generally applicable only to

carmustine, cyclophosphamide, and melphalan

patients under 65. Complete remission is generally associated

• Weekly cyclophosphamide (“C weekly”)

with prolonged survival. Median duration of CR is two years

and median overall survival is five years with this approach.

Allogeneic bone marrow transplantation may cure myeloma

but carries significant treatment-related morbidity and

mortality. It is generally restricted to patients under 50 with a

compatible sibling. This treatment offers a 33% chance of

durable remission and possible cure, 33% chance of survival

with recurrence and 33% risk of transplant-related mortality.

MP therapy

2nd line Rx

MMMMMMMMMM

MMMMMM

Terminal

plateau

Plateau phase

Most patients achieve a stable partial response with standard

Melphalan

melphalan therapy with

50% reduction in the M protein. In

resistance

plateau phase cessation of chemotherapy is not followed by a

rise in the M band or further signs of progression for many

2nd

Plateau

plateau

months (median 6-12). Maintenance interferon alfa may

phase

prolong the plateau phase by six months, but little evidence

exists of improved survival. Bisphosphonate treatment reduces

the rate of further bone damage and may have an additive

Time (months)

analgesic effect in patients with pre-existing damage. A survival

benefit has been demonstrated in clinical trials and may reflect

Figure 9.6 Natural history of multiple myeloma after melphalan

treatment

an effect of this treatment on the bone marrow

microenvironment.

Disease progression

With regular follow up, serological detection of disease allows

chemotherapy to be restarted before new bone damage

develops. In many patients several separate periods of plateau

phase may be re-induced by chemotherapy. Inevitably, myeloma

becomes resistant to melphalan; oral dexamethasone may

Multiple myeloma and related conditions

achieve further responses, and oral low dose cyclophosphamide

daily is often effective palliative treatment in combination with

local radiotherapy to sites of bone pain. Thalidomide controls

myeloma in over 20% of patients with advanced myeloma, and

in combination with dexamethasone it achieves responses in up

to 70% of patients previously treated with chemotherapy. Novel

molecular therapies and derivatives of thalidomide show great

potential.

Conditions related to multiple

myeloma

Monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance is

defined by the presence of an M protein in a patient without

multiple myeloma, Waldenström’s macroglobulinaemia,

amyloidosis, lymphoma, or other related disease. The

prevalence of monoclonal gammopathy of undetermined

significance is about 20 times greater than that of multiple

Figure 9.7 Bone pain from mechanical effects of myeloma damage (as in

spine shown here) often necessitates long term treatment with strong

myeloma, and the incidence increases with age (1% at over

analgesia despite response to chemotherapy

50 years; 3% at over 70).

Multiple myeloma, macroglobulinaemia, amyloidosis, or

lymphoma ultimately develops in 26% of patients with

monoclonal gammopathy of undetermined significance, with

No treatment is indicated for monoclonal gammopathy of

an actuarial rate of 16% at 10 years.

undetermined significance, but follow up is necessary

Solitary plasmacytoma

About 5% of patients have a single bone lesion at diagnosis

Box 9.9 Diagnostic criteria for monoclonal

with no evidence of disseminated bone marrow involvement.

gammopathy of undetermined significance

Generally M protein is absent (up to 70% of cases) or present

in low concentration. Plasmacytoma may be cured by local

• No unexplained symptoms suggestive of myeloma

• Serum M protein concentration

30 g/l

radiotherapy. Patients with solitary plasmacytoma should be

•

5% plasma cells in bone marrow

monitored for evidence of myeloma, which develops in most

• Little or no M protein in urine

cases. Further plasmacytomas may develop, and magnetic

• No bone lesions

resonance imaging may show bone lesions undetectable by

• No anaemia, hypercalcaemia, or renal impairment

conventional radiology. Median survival is over 10 years.

• M protein concentration and other results stable on

prolonged observation

Waldenström’s macroglobulinaemia

This tumour is due to proliferation of lymphoid cells which

produce monoclonal IgM. The median age at presentation is

Box 9.10 Plasma cell leukaemia

63 years, and over 60% of patients are male. Many of the

• May be diagnosed when blood plasma cells exceed

clinical features are due to hyperviscosity. Weakness, fatigue,

2.0

10⁹/l

and bleeding are the most common presenting complaints,

• May occur as a terminal stage in advanced multiple

followed by visual upset, weight loss, recurrent infections,

myeloma or as aggressive disease at diagnosis in under 5%

dyspnoea, heart failure, and neurological symptoms. Bone pain

of cases

• Bone involvement is often minimal, and the M protein

is rare.

concentration is often low

The erythrocyte sedimentation rate is greatly raised,

• Results of treatment are poor, intensive treatment can

and when the plasma viscosity exceeds 4 cP most patients

induce responses and prolong survival

have symptoms of hyperviscosity. Serum protein

immunoelectrophoresis shows an IgM paraprotein.

Monoclonal light chains may be present in the urine.

Trephine biopsy often shows extensive infiltration with

Box 9.11 Clinical and laboratory features of

plasmacytoid lymphocytes.

Waldenström’s macroglobulinaemia

Symptomatic hyperviscosity is corrected by plasmapheresis.

• Fatigue and weight loss

Chlorambucil with or without prednisolone for one week every

• Anaemia

• Hyperviscosity syndrome (may cause chronic oral or nasal

4-6 weeks frequently reduces bone marrow infiltration, the IgM

bleeding, visual upset, headache, vertigo, hearing loss,

concentration, and plasma viscosity. Median survival is about

ataxia, somnolence, and coma)

five years. The purine analogue fludarabine is effective in this

• Retinal haemorrhages

condition.

• Venous congestion (sausage formation) in retinal veins

• Recurrent infection

Other related conditions

• Lymphadenopathy

Chronic lymphocytic leukaemia and diffuse low grade non-

• Hepatosplenomegaly

• Raised erythrocyte sedimentation rate

Hodgkin’s lymphoma may be associated with low serum

• High serum monoclonal IgM concentration

concentrations of monoclonal IgG or IgM. This finding has no

• Lymphoplasmacytoid bone marrow infiltrate

prognostic importance for these patients. Primary amyloidosis

ABC of Clinical Haematology

Box 9.12 Key points

Further reading

• Bataille R, Harrousseau JL. Multiple myeloma. N Engl J Med

• In some cases distinguishing multiple myeloma from

monoclonal gammopathy of undetermined significance can

1997;336:1657-64.

•

Boccadoro M, Pileri A. Diagnosis, prognosis and standard

be difficult

• Prognostic factors are available which may help identify

treatment of multiple myeloma. Hematol Oncol Clin North Am

1997;11:111-31.

patients with myeloma in whom treatment may not be

necessary, and others where aggressive treatment is

•

Croucher PI, Apperley JF. Bone disease in multiple myeloma.

Br J Haematol 1998;103:902-10.

warranted

• Early chemotherapy may reverse renal impairment and

•

Fassas A, Tricot G. Results of high dose treatment with

autologous stem cell support in patients with multiple myeloma.

dialysis may be appropriate supportive therapy for some

patients

Semin Hematol 2001;38:231-42.

•

Gahrton G, Svensson H, Cavo M et al. Progress in allogeneic

• Bisphosphonate therapy helps reduce the incidence of bony

complications

bone marrow and peripheral blood stem cell transplantation

for multiple myeloma: a comparison between transplants

• Allogeneic bone marrow transplantation should be

considered in younger myeloma patients (

55 years) if a

performed 1983-93 and 1994-8 at the European Group for Blood

and Marrow Transplantation centres. Br J Haematol

compatible sibling donor is available since this may be

curative

2001;113:209-16.

•

Gillmore JD, Hawkins PN, Pepys MB. Amyloidosis: a review of

recent diagnostic and therapeutic developments. Br J Haematol

1997;99:245-56.

•

Kyle RA. Monoclonal gammopathy of undetermined significance

and solitary plasmacytoma. Hematol Oncol Clin North Am

is associated with an M protein in 85%. The “heavy chain

1997;11:71-83.

diseases” are rare lymphoproliferative disorders in which the

abnormal cells excrete only parts of immunoglobulin heavy

chains ( ,

, or

Mr Darren Costello supplied the protein electrophoresis strip.

Bleeding disorders, thrombosis, and

anticoagulation

K K Hampton, F E Preston

Blood within the vascular tree remains fluid throughout life, but

Box 10.1 History in bleeding disorders

if a blood vessel is damaged, blood will clot in a rapid localised

• Abnormal bruising

response. Failure of clotting leads to bleeding disorders;

• Abnormal bleeding from cuts and abrasions

thrombosis is inappropriate clotting within blood vessels. The

• Nosebleeds

haemostatic system is complex, and many congenital and

• Menorrhagia

acquired conditions can disturb its correct functioning.

• Haemarthrosis

• Bleeding after dental extraction

•

Bleeding during childbirth

• Bleeding during surgery

Bleeding disorders

• Previous anaemia and transfusions

• Drug history

History

• Family history

Personal and family history is as important as laboratory

investigation in assessing bleeding disorders. Easy bruising,

nosebleeds (especially in children), and menorrhagia are

common and do not necessarily signify a haemostatic defect

unless they are persistent and severe. Small bruises on the limbs

in response to minor trauma and simple easy bruising are

especially common in elderly people and those receiving long

term corticosteroids.

Large bruises after minimal trauma and on the trunk may

indicate an important haemostatic defect. Abnormally

prolonged bleeding from minor cuts and scratches and delayed

recurrence of bleeding are also important, as is gum bleeding if

there is no gingival disease and if it is unrelated to the trauma

of brushing. Repeated nosebleeds lasting more than 10 minutes

despite compression suggest a local cause or an underlying

bleeding disorder.

The haemostatic response to previous haemostatic

Persistent menorrhagia sufficient to cause iron deficiency

challenges is informative, especially in mild conditions, when

anaemia may indicate a bleeding disorder if no structural

spontaneous bleeding is rare. A history of excessive bleeding or

uterine abnormality is present

recurrence of bleeding after dental extractions, circumcision,

tonsillectomy, other previous surgical operations, and

childbirth should be sought, as should a history of unexplained

anaemia, gastrointestinal bleeding without the demonstration

of a cause, and previous blood transfusion.

A drug history should be taken to assess intake of aspirins

Table 10.1 Screening tests for bleeding disorders

and non-steroidal anti-inflammatory drugs, and appropriate

Test

Abnormality detected

questioning will suggest causes for acquired haemostatic

disorders, such as excessive alcohol intake, liver disease, or

Blood count and Anaemia, leukaemia, disseminated

renal disease.

film

intravascular coagulation

An inherited bleeding condition will result in a family

Platelet count

Thrombocytopenia

history of the condition and suggest a pattern of inheritance—

Activated partial

Deficiency of all coagulation factors

for example, autosomal dominant inheritance (both sexes

thromboplastin

except VII, especially follows VIII and IX;

affected) or X-linked inheritance (only males affected).

time

heparin

In severe coagulation factor deficiency, such as haemophilia

Prothrombin time

Deficiency of factors I, II, V, VII, and X;

warfarin

A or B, bleeding occurs primarily into muscles and joints,

Thrombin time or Hypofibrinogenaemia or dysfibrinogenaemia;

whereas in platelet disorders and von Willebrand’s disease

fibrinogen

heparin; fibrin degradation products

bleeding tends to be mucocutaneous—for example,

Bleeding time

Test of platelet-vessel wall interaction

nosebleeds, menorrhagia, and gum and gastrointestinal

bleeding.

Laboratory investigation

The vast majority of important bleeding disorders can be

excluded if the findings are all normal for blood and platelet

counts, blood film, prothrombin time, activated partial

Patients who have unexplained abnormalities on screening

thromboplastin time, fibrinogen or thrombin time, and

investigations should be referred for specialist

bleeding time. These tests will reveal quantitative platelet

investigation and management

disorders and congenital or acquired deficiency of coagulation

ABC of Clinical Haematology

factors, which can be confirmed by specific assay. The tests will

Table 10.3 Clinical severity of haemophilia A and B

not, however, detect all bleeding disorders, especially those due

to vascular causes and mild von Willebrand’s disease, and

Factor value*

Bleeding tendency

patients with a strong personal or family history of the

0.02

Severe—frequent spontaneous bleeding into

condition, despite normal screening investigation, should be

joints, muscles, and internal organs

referred for specialist investigation and management.

0.02-0.05

Moderate—some “spontaneous” bleeds,

bleeding after minor trauma

Congenital disorders

0.05

Mild—bleeding only after significant trauma or

Haemophilia A and B are rare conditions with a combined

surgery

incidence of about 1:10 000 of the population. They are due to

* Normal value of factors VIII and IX is 0.5-1.5

a deficiency of coagulation factors VIII (haemophilia A) and IX

(haemophilia B). As the genes for both proteins are on the X

chromosome, both haemophilias have sex-linked inheritance—

the daughters of a man with haemophilia are therefore obligate

carriers. Patients with severe haemophilia (less than 2% factor

VIII or IX) have spontaneous bleeding into muscles and joints

that can lead to a crippling arthropathy. Patients with moderate

(2-5%) and mild (

5%) conditions usually bleed only after

trauma or surgery. Management is highly specialised and

consists of preventing or treating bleeding episodes with

plasma-derived or recombinant clotting factors.

Von Willebrand’s disease is a common bleeding disorder,

with an incidence of up to 1% in some populations. Most cases

are mild, with bleeding only after a haemostatic challenge.

Menorrhagia is common in affected women. Inheritance is

autosomal dominant, with males and females equally affected.

The condition is due to a reduction or structural abnormality

of von Willebrand factor, which has the dual role of promoting

normal platelet function and stabilising coagulation factor VIII.

Von Willebrand’s disease can give normal results on screening

tests, and diagnosis may require specialist investigation. Most

patients with mild disease respond to desmopressin (DDAVP),

but clotting factor concentrates are needed for a minority.

Figure 10.1

Acute haemarthrosis of knee joint

Acquired disorders

Most proteins of the coagulation cascade and their regulators

and inhibitors necessary for haemostasis are synthesised in the

liver. Acquired abnormalities can be due to impaired synthesis,

increased consumption, or rarely the formation of

autoantibodies against coagulation proteins. Liver disease can

cause a severe bleeding disorder, with prolongation of the

prothrombin time particularly, often with coexistent

thrombocytopenia due to excessive pooling of platelets in an

Table 10.2 Clinical features of coagulation factor

deficiency and platelet type/von Willebrand’s disease

Platelet/von

Coagulation

Willebrand’s

Figure 10.2

Pathological bruising in von Willebrand’s disease

defect

disease

Bruises

Large, on body

Small

Table 10.4 Acquired bleeding disorders

and limbs

Bleeding

Not severe

Profuse

Disease

Pathophysiology

from cuts

Nosebleeds

Not common

Common, often

Liver disease and

Decreased synthesis of coagulation

prolonged

cirrhosis

factors, thrombocytopenia

and severe

Gastrointestinal

Vitamin K deficiency

Gastrointestinal

Uncommon, no

Common

malabsorption

bleeding

underlying lesion

Shock/sepsis/

Disseminated intravascular coagulation,

Haemarthrosis

Common in severe

Very uncommon

malignancy

increased consumption of coagulation

haemophilia

factors and platelets

Haematuria

Common

Rare

Renal disease

Acquired platelet dysfunction

Bleeding

Delayed 12-24 hours

From time of

Lymphoproliferative

Acquired autoantibodies to specific

after dental

after haemostatic

challenge

disorders/spontaneous

coagulation factors (inhibitors)

extraction and

challenge

Amyloidosis

Acquired factor X deficiency, blood

surgery

vessel infiltration

Bleeding disorders, thrombosis, and anticoagulation

enlarged spleen. Malabsorption of vitamin K from the gut can

Box 10.2 Risk factors for venous thrombosis

cause a coagulation disorder similar to that caused by ingestion

Environmental

of warfarin. Disseminated intravascular coagulation is a rare

• Immobility

cause of an acquired severe systemic failure of haemostasis with

• Surgery, trauma

simultaneous microvascular thrombosis and generalised

• Pregnancy, puerperium

bleeding. Overwhelming bacterial infections—for example,

• Long distance travel

meningococcal septicaemia or disseminated malignancies (such

• Use of combined oral contraceptives

as prostatic, pancreatic, and acute promyelocytic leukaemia)—

Inherited

are the most common causes. Renal disease causes a variable

• Antithrombin deficiency

• Protein C deficiency

bleeding disorder primarily due to platelet dysfunction;

• Protein S deficiency

advancing age, prolonged use of steroids, and vitamin C

• Factor V Leiden (activated protein C resistance, APCR)

deficiency can all result in excessive bruising. Abnormal

• Prothrombin PT20210A allele

bleeding has been reported with myeloproliferative,

Acquired

myelodysplastic, and lymphoproliferative disorders.

• Antiphospholipid antibody, lupus anticoagulant

• Hyperhomocysteinaemia

Arterial thrombosis

• Malignancy

Arterial thrombosis results in myocardial infarction, stroke, and

• Myeloproliferative diseases

peripheral vascular disease. Atherosclerotic lesions form in the

vessel wall, resulting in narrowing and subsequent plaque

rupture, which cause vessel occlusion. Risk factors for

atherosclerosis include smoking, hypertension, diabetes,

hypercholesterolaemia, hyperlipidaemia, and

hyperfibrinogenaemia. Platelet deposition occurs on a

ruptured arteriosclerotic plaque, and the antiplatelet drugs

aspirin and clopidogrel are widely used in the treatment and

secondary prophylaxis of arterial thrombosis.

Venous thrombosis

Venous thrombosis results in deep vein thrombosis and

pulmonary embolism and is due to a combination of blood

stasis and hypercoagulability. The clinical diagnosis of venous

thromboembolic disease is notoriously unreliable, and objective

confirmation with ultrasonography or venography for deep

vein thrombosis and ventilation perfusion scanning or

pulmonary angiography for pulmonary embolus must be

performed. Recently it has become clear that venous

thrombosis is frequently due to a combination of

environmental factors (such as surgery and pregnancy), with an

Figure 10.3 Contrast venogram showing extensive thrombosis with

underlying genetic predisposition due to inherited deficiencies

intraluminal filling defects and vessel occlusion

or abnormalities of the proteins of the natural anticoagulant

pathway, which functions to inhibit or limit thrombin

formation. The familial thrombophilic disorders include factor

V Leiden, prothrombin 20210A and deficiencies of protein C,

Box 10.3 Clinical features of familial thrombophilia

protein S, and antithrombin.

The incidence of factor V Leiden, which causes activated

• Family history of venous thromboembolism

• First episode at early age

protein C resistance (APCR), is 3-5%, and that of the

• Recurrent venous thromboembolism

prothrombin 20210A allele is 2-3% in Caucasian populations.

• Unusual site of thrombosis—eg cerebral, mesenteric

These are thus the commonest causes of an inherited

• Thrombosis during pregnancy or puerperium

predisposition to venous thrombosis (thrombophilia), despite

• Spontaneous venous thrombosis without environmental or

being rare in other ethnic groups. All the hereditary

acquired risk factor

thrombophilic conditions are autosomally dominantly inherited

• Recurrent superficial thrombophlebitis

and are present in up to 50% of cases of venous thrombosis,

particularly when recurrent, familial, or at a young age.

Detection of one of these conditions may influence the future

management of the individual with regard to

Box 10.4 Recommended international normalised ratio

thromboprophylaxis and anticoagulation.

ranges

Consideration should also be given to possible family

2.0-3.0

screening. Unfortunately, the presence of active thrombosis and

• Treatment of deep vein thrombosis and pulmonary

treatment with both heparin and warfarin make testing for the

embolism

above deficiency conditions unreliable, and testing should be

• Atrial fibrillation

delayed until active thrombosis has resolved and anticoagulants

• Mitral stenosis with embolism

have been discontinued. The genetic tests for the factor V

• Transient ischaemic attack

Leiden defect and the prothrombin 20210A allele are, of course,

3.0-4.5

• Recurrence of deep vein thrombosis or pulmonary

unaffected by anticoagulant therapy and on-going thrombosis.

embolism while taking warfarin

An acquired predisposition to both arterial and venous

• Mechanical prosthetic heart valves

thrombosis occurs in the antiphospholipid syndrome, which

ABC of Clinical Haematology

can either be primary or secondary to an underlying collagen

vascular disorder. Laboratory diagnosis of this condition entails

the detection of antibodies to cardiolipin or a lupus

anticoagulant, or both. The latter causes in vitro a prolonged

activated partial thromboplastin time and a prolonged dilute

Russell’s viper venom test, which corrects with excess

phospholipids, but it is paradoxically associated in vivo with

thrombosis. Lupus anticoagulants can also be induced by

infections and drugs, and in these circumstances are not

usually associated with thrombosis.

Anticoagulation

Warfarin

Warfarin is an oral anticoagulant that results in the synthesis by

the liver of non-functional coagulation factors II, VII, IX, and

X, as well as proteins C and S, by interfering with vitamin K

metabolism.

Warfarin prolongs the prothrombin time, and dosage

monitoring is achieved by a standardised form of this test, the

international normalised ratio (INR).

Recommended target ranges and duration of treatment

Figure 10.4 Intracerebral bleeding in patient taking warfarin

have been published; an INR target of 2.5 with a range of 2 to 3

being appropriate for most cases.

Warfarin treatment requires regular monitoring as

over-treatment carries an important haemorrhagic risk, and

Table 10.5 Reversal of oral anticoagulation

warfarin requirements may be affected by intercurrent illness

or concurrent drug treatment. Dental extraction or minor

Condition

Treatment

surgery is usually safe if the INR is less than 2.0, whereas for

INR

4.5

Stop warfarin transiently and review

major surgery warfarin should be discontinued and parenteral

without bleeding

heparin substituted.

INR

4.5 with

Stop warfarin and consider small

In pregnancy warfarin is absolutely contraindicated from 6

minor bleeding

doses of intravenous vitamin K

to 12 weeks of gestation as it may damage the fetus. Because

Life threatening

Stop warfarin; give intravenous

warfarin crosses the placenta and affects the fetus, heparin is

bleeding

vitamin K 5 mg; give factors II, IX, X,

increasingly being substituted throughout pregnancy as the

and VII concentrate (50 units/kg

drug of choice for thromboprophylaxis.

factor IX) if available (if concentrate is

unavailable give 15-25 ml/kg fresh

Reversal of a high INR can be addressed in several ways,

frozen plasma)

depending on the circumstances. In the absence of bleeding,

Unexpected

Consider unsuspected underlying

omitting warfarin is usually sufficient. Minor bleeding episodes

bleeding at any INR

structural lesion

can be treated with local measures and small doses of

INR international normalised ratio

vitamin K. Life threatening bleeding requires resuscitation of

the patient together with treatment with a prothrombin

complex clotting factor concentrate; fresh frozen plasma can

be used if concentrate is not available, but it is considerably less

Further reading

effective.

Anon. Guidelines on oral anticoagulation: third edition. Br J

•

Haematol 1998;101:374-87.

Heparin

• Cattaneo M, Monzani ML, Martinelli I, Falcon CR,

Heparin is a parenterally active anticoagulant that acts by

Mannucci PM. Interrelation of hyperhomocysteinemia, factor V

potentiating the antithrombotic effects of antithrombin and

Leiden, and risk of future venous thromboembolism. Circulation

can be used for both prophylaxis and treatment of venous

1998;97:295-6.

• D’Angelo A, Selhub J. Homocysteine and thrombotic disease.

thromboembolic disease. Unfractionated heparin is usually

Blood 1997;90:1-11.

given intravenously and is monitored by prolongation of the

• Dahlback B. Resistance to activated protein C as risk factor for

activated partial thromboplastin time. It has a narrow

thrombosis: molecular mechanisms, laboratory investigation, and

therapeutic range with complex pharmacokinetics and great

clinical management. Semin Hematol 1997;34:217-34.

interpatient variation in dose requirements. Low molecular

• Preston FE, Rosendaal FR, Walker ID et al. Increased fetal loss in

weight heparins are replacing unfractionated heparin for the

women with heritable thrombophilia. Lancet 1996;348:913-16.

• Zivelin A, Griffin JH, Xu X et al. A single genetic origin for a

prophylaxis of medical and surgical patients and the treatment

common Caucasian risk factor for venous thrombosis. Blood

of venous thromboembolic disease. They can be administered

1997;89:397-402.

by once daily subcutaneous injection without monitoring.

Malignant lymphomas and chronic

lymphocytic leukaemia

G M Mead

The malignant lymphomas (non-Hodgkin’s lymphoma and

Management of the malignant lymphoma is complex and is

Hodgkin’s disease) are a clinically and pathologically diverse

best carried out in specialised treatment centres

group of cancers of largely unknown cause that are rapidly

increasing in incidence. They are highly treatable and sometimes

curable. Chronic lymphocytic leukaemia (CLL), the commonest

adult leukaemia, shares many features with these cancers. The

Box 11.1 Ann Arbor staging system for lymphoma

whole group constitutes about 5% of malignant diseases.

Site

• Stage I: Single lymphoid area or extranodal site (stage IE)

•

Stage II: Two lymphoid areas or extranodal sites on the

same side of the diaphragm

Pathology and staging

• Stage III: Lymphoid areas (including the spleen) on both

sides of the diaphragm

The non-Hodgkin’s lymphomas (NHL) arise from malignant

• Stage IV: Diffuse involvement of an extranodal organ(s)

transformation of lymphocytes, deriving from B cells in about

(liver, bone marrow)

85% of cases and T cells in most of the rest. Chronic

Symptoms

lymphocytic leukaemia is largely a B cell malignancy. It has

• A: No symptoms

become increasingly clear that Reed Sternberg cells, which

• B:

10% weight loss, drenching night sweats, or

characterise Hodgkin’s disease, are usually also of B cell origin.

unexplained fevers

38 C

Histopathologically, lymphomas comprise an admixture of

identical (monoclonal) malignant cells with variable amounts of

reactive lymphoid cells and stroma. The lymphomas are

Box 11.2 Binet staging system for chronic lymphocytic

subcategorised by pathologists into about 20 different types on

leukaemia

the basis of conventional cytological staining, special staining to

Stage A No anaemia or thrombocytopenia; fewer than three

determine subtype and lineage, and chromosomal abnormalities.

enlarged lymphoid areas

A diagnosis of lymphoma (or even B or T cell lymphoma)

Stage B As for stage A but three or more enlarged lymphoid

areas

gives no clue to the natural course of the disease in an individual

Stage C Anaemia (concentration

100 g/l) and/or platelet

patient. Clinicians treating these patients take account of the

count

100

10⁹/l

histopathology and the history provided by the patient, as well as

many other factors (for example, stage and age), before

recommending treatment or advising about prognosis. The

complexity of non-Hodgkin’s lymphomas requires a simplified

management approach, on the basis of division of cases into low

grade (or indolent), intermediate, and high grade disease.

All patients with lymphoma or CLL require careful initial

staging, usually comprising physical examination, measurement

of an LDH level, computed tomography, and a bone marrow

biopsy. Lymphomas are staged with the Ann Arbor system and

CLL with the Binet system. Increasingly, treatment is decided on

the basis of allocated stage together with an examination of other

known prognostic factors. For NHL an International Prognostic

Index (IPI) score is allocated which relates to prognosis.

Figure 11.1 Follicular lymphoma (low power)

Low grade non-Hodgkin’s

Box 11.3 Presenting features of low grade

lymphomas and chronic lymphocytic

non-Hodgkin’s lymphoma

leukaemia

• Painless peripheral lymphadenopathy

• Abdominal mass (nodal or spleen)

The low grade non-Hodgkin’s lymphomas and chronic

• Weight loss

lymphocytic leukaemia are rare in patients aged under 40 years

• Night sweats

and are predominantly diseases of elderly people (90% of

patients are aged

50 years).

Box 11.4 Presenting features of chronic lymphocytic

leukaemia

Nodal non-Hodgkin’s lymphomas

• As for low grade non-Hodgkin’s lymphoma

• Asymptomatic: diagnosed coincidentally

and chronic lymphocytic leukaemia

• Fatigue

• Anaemia

This group includes most of the follicular lymphomas and

• Infection

constitutes about 30% of the cases of non-Hodgkin’s

ABC of Clinical Haematology

lymphoma. Chronic lymphocytic leukaemia has a similar

natural course. Diagnosis may be incidental (for example, from

a routine blood count, as in CLL) or may follow a period of

(often fluctuating) localised or generalised enlargement of

lymph nodes or the spleen. These lymphomas are usually

widespread at diagnosis, commonly (as in non-Hodgkin’s

lymphoma) or always (CLL) involving the bone marrow.

Because of their indolent nature, however, there may be little

or no initial effect on quality of life. Some patients, however,

present with B symptoms or bulky widespread disease and need

early treatment.

The management of these cancers is adjusted to their

natural course. Cure can rarely be achieved, and the median

overall survival in most series is 8-10 years. Prognosis relates to

age (poorer when older) and particularly to the extent of

disease judged in terms of bulk and effect of tumour. The

Figure 11.2 Peripheral blood film of patient with chronic lymphocytic

outlook for chronic leukaemia worsens with increasing extent

leukaemia showing numerous malignant lymphocytes

of disease at presentation and cytopenias (Binet stage B and C).

Patients who are well with non-threatening disease (eg low

volume follicular lymphoma) may initially be watched without

100

treatment—on occasions for many years. Initial treatment when

needed generally comprises an alkylating agent-usually

intermittent chlorambucil—with or without steroids for 4-6

months. This will often be highly successful in causing disease

regression; relapse is, however, inevitable.

At relapse chlorambucil can be used again if initially

effective, or, particularly for CLL, fludarabine, an

antimetabolite can be given orally. Patients with follicular

lymphoma often respond well at relapse to rituximab, a

monoclonal B cell antibody given intravenously.

After several years the lymphomas may become refractory to

treatment or may “transform” with change in histology and

Time (years)

clinical course to an intermediate grade non-Hodgkin’s

lymphoma. If this occurs then combination chemotherapy is

Figure 11.3 Survival curve of 160 patients with advanced follicular

recommended, but the outlook is usually poor.

lymphoma: survival is prolonged, but there is no evidence of cure

Newer treatment approaches under evaluation include (in

younger patients) high dose chemotherapy with stem cell

support, and for follicular lymphoma, monoclonal antibodies

linked to a therapeutic radio-isotope (radio-immunotherapy).

Extranodal lymphoma (maltoma or

marginal zone lymphoma)

Cell death

These are indolent lymphomas that arise most commonly in

the stomach, thyroid, parotid and lung—often evolving from a

pre-existing inflammatory or autoimmune disease (for

example, in the stomach gastritis relating to Helicobacter pylori,

Antigen on target malignant B cell

or in the parotid gland, Sjogren’s syndrome). Gastric maltoma

Antibody (

) coupled to ricin (

)

can be successfully managed in most cases by treatment of

H pylori with appropriate antibiotics. Complete response, which

Figure 11.4 “Targeted” antibody therapy of lymphoma. The antibody

is sustained, occurs in most cases—a unique example of

delivers a toxin (ricin) to the lymphocytes bearing the appropriate

regression of malignancy by treatment of infection. Remaining

surface antigen

maltomas are generally managed with local radiotherapy with

very high success rates.

The maltomas can progress to intermediate grade

lymphomas. In addition, they can metastasise, usually to the

other malt sites described above.

Intermediate grade non-Hodgkin’s

lymphoma

This is the most common grade of non-Hodgkin’s lymphoma

(65%) and affects any age group. It is rapidly increasing in

incidence, although the reasons for this are uncertain.

Malignant lymphomas and chronic lymphocytic leukaemia

Two-thirds of cases of this type of cancer arise within lymph

nodes—patients present because of lymph node enlargement.

The remaining cases may arise in almost any other tissue or

organ (for example, gastrointestinal tract, skin, brain and

bone), with symptoms appropriate to each site.

The most common type is diffuse large B cell lymphoma.

These lymphomas occur at any age (median 65 years) and are

rapidly progressive cancers that are often associated with

B symptoms. Diagnosis and staging should be urgently

performed then treatment with chemotherapy started. These

cancers are curable in about 40% of cases. The prognosis

relates to the patient’s age, extent of spread, lactate

dehydrogenase concentrations, and performance status.

The standard chemotherapy is a combination of

cyclophosphamide, doxorubicin, vincristine, and prednisolone

(CHOP), given intravenously at intervals of three weeks in the

outpatient clinic on six occasions and sometimes supplemented

by radiotherapy.

Relapse is not uncommon, and in the past it was associated

with a poor outlook. However, younger patients with disease

that has remained sensitive to chemotherapy may now be cured

Figure 11.5

Intermediate grade non-Hodgkin’s lymphoma arising in skin

in up to 50% of cases using high dose chemotherapy. Survival

in remaining patients is often measurable in months.

Newer treatments under evaluation are rituximab, given

100

with CHOP at the time of initial treatment, and radio

immunotherapy.

High grade non-Hodgkin’s

lymphoma

This grade of the disease is rare (under 5% of all cases) and

comprises rapidly progressive cancers of children and young

adults.

Lymphoblastic lymphoma is a T cell lymphoma identical to

Time (years)

T cell acute lymphoblastic leukaemia, which occurs

predominantly in young males who usually present with a

mediastinal mass. Involvement of the bone marrow and central

Figure 11.6

Survival of 760 patients with large cell non-Hodgkin’s

lymphoma (40% cure rate)

nervous system commonly occur. Burkitt’s lymphoma is a rare

B cell neoplasm of young adults, cytologically identical to B cell

acute lymphoblastic leukaemia, that usually arises at extranodal

sites, most commonly in the gastrointestinal tract—for example,

the ileocaecal region. This lymphoma also commonly spreads

to the bone marrow and the central nervous system.

Both these lymphoma types are curable with intensive

combination chemotherapy.

Treatment of these cancers is urgent and may, if adequate

precautions are not taken, be complicated by the acute tumour

lysis syndrome resulting from breakdown of the lymphoma.

This can lead to renal failure and possible death. Intrathecal

chemotherapy to prevent relapse in the central nervous system

is routinely used. Overall cure rates generally exceed 50%.

AIDS related non-Hodgkin’s

lymphoma

The immunosuppression associated with HIV infection has

been associated with a noticeable increase in the incidence of

non-Hodgkin’s lymphoma and Hodgkin’s disease.

These diseases arise in many cases because of uninhibited

expansion of multiple clones of lymphocytes infected with

Epstein-Barr virus. They are commonly high grade B cell

neoplasms that arise at extranodal sites—for example, the brain

Figure 11.7 Anterior mediastinal mass in adolescent male: histological

and the ileocaecal area. The outlook for patients with these

tests revealed lymphoblastic lymphoma

ABC of Clinical Haematology

Box 11.5 Treatment of AIDS related non-Hodgkin’s

lymphoma

• Treatment is often difficult because of pre-existing

immunosuppression and AIDS related infection

•

Chemotherapy together with antiretroviral therapy are

indicated; the prognosis relates to the degree of

immunosuppression at diagnosis

•

Cure of these lymphomas is possible, although the outlook

is usually very poor

cancers has markedly improved since the introduction of

effective antiretroviral therapy.

Hodgkin’s disease

Figure 11.8 Karyotyping may aid lymphoma diagnosis. Here 8;14

translocation is shown in Burkitt’s NHL

Pathology

Hodgkin’s disease has classically been divided into four types.

Recent studies suggest, however, that one type—lymphocyte

Hodgkin’s disease is an uncommon form of lymphoma

predominant (LPHD)—is a clinically distinct B cell lymphoma

occurring mainly at ages 15-35 years and affects slightly

often presenting with isolated enlargement of a peripheral

more men than women

lymph node.

The nodular sclerosing type constitutes 70-80% of cases of

Hodgkin’s disease and classically presents in young women with

mediastinal and cervical nodal disease.

Box 11.6 Symptoms and signs of Hodgkin’s disease

Mixed cellularity disease occurs predominantly in older

• Painless lymphadenopathy

males and is more commonly widespread. Lymphocyte

• B symptoms

depleted Hodgkin’s disease is rare.

• Pruritus

Clinical presentation and management

Hodgkin’s disease most commonly presents as enlargement of

supradiaphragmatic lymph nodes with or without B symptoms.

Table 11.1 Clinical features of Hodgkin’s disease vs

Generalised pruritus can be a presenting feature in some cases.

non-Hodgkin’s lymphoma

The spleen is involved in at least 30% of cases, and in the past

Non-Hodgkin’s

the disease was detected with splenectomy. This procedure has

Hodgkin’s disease

lymphoma

now been abandoned as studies suggested no overall survival

benefit from this procedure. Modern management relies on

Incidence

Stable

Increasing

assessment of prognostic factors. The staging is as for

Age

Median 29 years

Increasing incidence

non-Hodgkin’s lymphoma with the Ann Arbor system.

with age

Patients with stage I LPHD should be managed with

Sites

Nodal;

Nodal or extranodal;

localised irradiation with a high chance of cure. Increasingly, all

supradiaphragmatic

any site

other stage I or II cases are treated with a combined approach,

Clinical

Mediastinal mass;

Nil specific

receiving initial intravenous combination chemotherapy

features

itching; alcohol

induced pain

supplemented by irradiation with a high chance (95%) of cure.

Prognosis

70-80% cure

Highly variable by type;

Patients with more extensive or symptomatic disease are treated

most incurable

primarily with combination chemotherapy, sometimes

supplemented by irradiation to bulky sites. The drug

combination ABVD (doxorubicin, bleomycin, vinblastine, and

dacarbazine) is accepted standard therapy, given intravenously

every two weeks for six months. Approximately 70% of patients

receiving this treatment, sometimes supplemented by irradiation

to bulky sites, will be cured. Fertility is usually preserved.

If relapse occurs, the standard treatment approach is with

high dose chemotherapy supported by peripheral blood stem

cell infusion. Cure rates of approximately 50% are achieved

with this treatment approach.

Long term studies have suggested that overall cure rates for

Hodgkin’s disease are stable at 70-80%, although it is hoped that

some of the newer chemotherapy approaches may improve these

figures. Increasingly patients with Hodgkin’s disease resume an

entirely normal life once treatment has been completed. A

particular concern, however, is an increased incidence of breast

Figure 11.9 Reed Sternberg cells in a typical mixed inflammatory

cancer in female patients who have received mantle radiotherapy.

background characterise Hodgkin’s disease

Malignant lymphomas and chronic lymphocytic leukaemia

Further reading

• Harris NL, Jaffe ES, Stein H et al. A revised European-American

classification of lymphoid neoplasms: a proposal from the

International Lymphoma Study Group. Blood 1994;84:1361-92.

• International Non-Hodgkin’s lymphoma prognostic factors

project. Predictive model for aggressive non-Hodgkin’s

lymphoma. N Engl J Med 1993;329:987-94.

• Horning SJ. Natural history of and therapy for the indolent non-

Hodgkin’s lymphoma. Semin Oncol 1993;20:75-88.

• Dighiero G, Maloum K, Desablens B et al. Chlorambucil in

indolent chronic lymphocytic leukaemia. N Engl J Med

1998;338:1506-14.

• Multani PS, Grossbard ML. Monoclonal antibody based therapies

for hematologic malignancies. J Clin Oncol 1998;16:3691-710.

• Zucca E, Bertoni F, Roggero E, Cavalli F. Gastric marginal zone

B-cell lymphoma of MALT type. Blood 2000;1996:410-19.

• Fisher RI, Gaynor ER, Dahlberg S et al. Comparison of a standard

regimen (CHOP) with three intensive chemotherapy regimens

for advanced non-Hodgkin’s lymphoma. N Engl J Med

1993;328:1002-6.

• Ratner L, Lee J, Tang S et al. Chemotherapy for human

immunodeficiency virus-associated non-Hodgkin’s lymphoma in

combination with highly active antiretroviral therapy. J Clin Oncol

2001;19:2171-8.

• Canellos GP, Anderson JR, Propert KJ et al. Chemotherapy of

advanced Hodgkin’s disease with MOPP, ABVD, or MOPP

Dr Dina Choudhury provided the blood film showing chronic

alternating with ABVD. N Engl J Med 1992;327:1478-84.

lymphocytic leukaemia (Figure 11.2).

Blood and marrow stem cell transplantation

Andrew Duncombe

History

Early animal studies of bone marrow transplantation were

translated into clinical practice with understanding of the

Experiments in the 1950s showed that haemopoiesis could be

human leucocyte antigen (HLA) system and

restored in irradiated animals by engraftment of transfused

immunosuppressive therapy

marrow. Attempts to translate this into clinical practice were

hindered by immunological problems of transfer between

individuals which we now recognise as rejection and graft

versus host disease.

With further understanding of the human leucocyte

antigen system, rapid clinical progress was made during the

1970s such that bone marrow transplantation soon became an

Method of stem

Generic term

Donor source

cell procurement

established treatment for some immune deficiency and

malignant diseases.

Bone marrow

Allogeneic

What is a stem cell transplant?

Peripheral blood

Transplantation is the reconstitution of the full haemopoietic

Haemopoietic

system by transfer of the pluripotent cells present in the bone

transplantation

marrow (stem cells). This usually requires prior ablation of the

Bone marrow

patient’s own marrow by intensive chemotherapy or

chemoradiotherapy.

Autologous

The most appropriate generic term for the procedure is

haemopoietic stem cell transplantation, which may be

subdivided according to the donor source and further

Peripheral blood

subdivided into the site of stem cell procurement.

Allogeneic transplantation is when another individual acts

Figure 12.1 Transplant terminology

as the donor—usually a sibling of the patient, sometimes a

normal volunteer. All cases, however, require a full or near

HLA match—that is, they should be HLA compatible.

Autologous transplantation is when the patient acts as his or

her own source of stem cells.

Originally, stem cells were procured from the bone marrow

The aim of haemopoietic transplantation is the elimination

by direct puncture and aspiration of bone marrow and

of the underlying disease in the recipient, together with

reinfused intravenously, a procedure known as bone marrow

full restoration of haemopoietic and immune function

transplantation. Recently, it has been shown that stem cells

derived from the bone marrow can be liberated into the

peripheral blood, where the cells are harvested with a cell

separation machine. Transplants with this stem cell material are

known as peripheral blood stem cell transplants. Stem cells

derived from the bone marrow or peripheral blood may be

used in either an allogeneic or an autologous setting.

Table 12.1 Indications for allogeneic transplantation

Conditions for which it is the sole chance of cure

Allogeneic transplantation

Primary immunodeficiency syndromes

Aplastic anaemia

Suitability

Thalassaemia

Owing to the profound toxicity of the transplant procedure,

Sickle cell disease

potential recipients should be otherwise healthy and usually

Inborn errors of metabolism

aged

55 years. As bone marrow contains B and T lymphocytes

Chronic myeloid leukaemia

along with macrophages the donor and recipient must be fully

Myelodysplasia

or near fully HLA matched to prevent life threatening graft

Multiple myeloma

versus host disease or rejection.

Conditions where there is probably benefit over conventional

This restricts the availability of potential donors. Within the

treatment

patient’s family the greatest chance of a full HLA match is with

Acute myeloid leukaemia (first or second complete remission)

a sibling. An average recipient in Western countries has about a

Acute lymphoblastic leukaemia(first or second complete

1 in 4 chance of having a sibling who is fully HLA matched.

remission)*

With this restriction in allogeneic transplantation, interest

*In children, where acute lymphoblastic leukaemia (ALL) is the

has surrounded the use of normal volunteer donors who show

commonest leukaemia, the majority will be cured by standard

a close HLA match to the potential recipient. This has been

chemotherapy alone without resort to transplantation, which is

achieved by the establishment of bone marrow registries in

reserved for those who relapse.

Blood and marrow stem cell transplantation

which volunteers agree to donate marrow. There are three such

Box 12.1 Indications for autologous transplantation

registries in Britain—the British Bone Marrow Registry run by

• Proven benefit in randomised controlled trials

the National Blood Service, the Welsh Bone Marrow Donor

Relapsed non-Hodgkin’s lymphoma (intermediate and high

Registry, run by the Welsh Blood Service, and the Anthony

grade)

Nolan panels. There is also an international registry known as

Acute myeloid leukaemia (first or second complete

Bone Marrow Donors Worldwide.

remission)

Although the size of bone marrow registries is increasing,

Multiple myeloma

the heterogeneity of the HLA complex means that there is still

• Probable benefit

a shortage of appropriately matched donors for all potential

Relapsed Hodgkin’s disease

Acute lymphoblastic leukaemia (first or second complete

recipients.

remission)

Relapsed testis cancer

• Possible benefit

Autologous transplantation

Chronic myeloid leukaemia

Severe autoimmune disease

Suitability

Less immunological disturbance occurs in autologous than in

allogeneic transplantation as the donor and the recipient are

the same individual; the stresses on the cardiorespiratory, skin,

and mucosal systems, however, are similar. Autologous

recipients therefore should still be otherwise healthy but can be

aged up to about 70 years.

Indications

The indications for autologous transplantation are being

continuously evaluated by a number of studies, including

randomised control trials, in many diseases, particularly

malignancy. The indications can best be broken down into those

in which there is now proved benefit in randomised controlled

trials, those in which there is probable benefit, and those in which

there is possible benefit. Results in solid tumours including RCTs

in breast cancer have generally been disappointing.

Figure 12.2

Haematologists performing bone marrow harvest

Obtaining the graft

Bone marrow is harvested by puncture of the iliac crests under

general anaesthesia. It is aspirated directly from the marrow

cavity with marrow biopsy needles.

Up to a litre of marrow may be needed to provide sufficient

stem cells for transplantation. The procedure is well tolerated,

requiring only simple analgesia postoperatively. Serious

complications are rare.

In peripheral blood stem cell transplantation, stem cells are

mobilised into the blood by single agent chemotherapy or a

haemopoietic growth factor (for example, granulocyte colony

stimulating factor), or both. When the white blood count rises

after 5-12 days, the individual is connected to a cell separation

machine, blood is drawn off and spun in a centrifuge, and stem

cells are harvested while the remaining blood elements are

returned to the patient. The procedure takes 2-4 hours and is

well tolerated.

Peripheral blood stem cell transplantation (PBSCT) is

gradually replacing bone marrow transplantation as the

Box 12.2 Peripheral blood compared to bone marrow

as source of haemopoietic stem cells

• Advantages

Simple procedure: no general anaesthetic

More rapid engraftment

Cheaper

? Lower relapse rates in CML allografts

• Disadvantages

? Higher rates of chronic GvHD

? Lower survival rates in aplastic anaemia

Figure 12.3

Extracorporeal cell separation device for collection of

No definitive answer yet to whether either source is superior

peripheral blood stem cells, showing inlet and outlet intravenous lines;

collected stem cell product is in bag above machine

ABC of Clinical Haematology

Box 12.3 Umbilical cord blood as source of stem cells

Allograft procedure

Autologous procedure

• Advantages

Recipient

Donor

Recipient*

Ease of access to source material

Adequate yields for paediatric recipients

Chemotherapy or

Harvesting of bone

? HLA matching less critical

chemoradiotherapy

marrow or peripheral

blood

• Disadvantages

? Higher risk of GvHD

? Sufficient stem cells for engraftment of large adults

Processing and

High costs of long term storage

cryopreservation

Chemotherapy or

procedure of choice as no general anaesthesia is needed,

chemoradiotherapy

engraftment is more rapid with earlier discharge from hospital,

and the procedure is cheaper.

Transplantation

Transplantation of

An alternative source of stem cells is umbilical cord blood

of stem cells

thawed stem cells

which is gaining popularity as cord blood banks become

established in the UK and Europe.

Severe

myelosuppression

Transplantation procedures

Allogeneic transplantation

Engraftment

The recipient is treated with high dose chemotherapy or

chemoradiotherapy to ablate the bone marrow (conditioning).

*In disease remission

On the day after the treatment has ended, bone marrow or

Figure 12.4 Transplantation procedures

peripheral blood stem cells are harvested from the donor, and

the transplant is performed by infusing the stem cells

intravenously. After a period of severe myelosuppression

lasting 7-21 days, engraftment of the transplanted material

Table 12.2 Factors affecting long term survival

takes place.

Factor

Better outcome with:

Autologous transplantation

The recipient, while in disease remission, undergoes a bone

Transplant type

Sibling allo. Unrelated allo.

Autologous

marrow or peripheral blood stem cell harvest. The stem cells

Recipient age

Younger patients

are processed and frozen in liquid nitrogen. The recipient then

Disease status

Early in disease or first remission

starts conditioning. One day after the conditioning has ended,

Presence or absence

GvHD survivors

the stem cell product is thawed and infused intravenously. The

of GvHD

bags are thawed rapidly by transfer directly from a liquid

Donor age

Younger donors

nitrogen container into water at 37-43 C. The product is

CMV serology

Donor and recipient negative

infused intravenously, rapidly through an indwelling central

line. Myelosuppression and engraftment follow as described

above.

One major procedural difference between allogeneic and

autologous transplantation is the requirement for

Box 12.4 Early complications of transplants

immunosuppression in allografts to prevent graft versus host

• Chemoradiotherapy

disease and rejection. This is achieved with combinations of

Nausea and vomiting

cyclosporin A and methotrexate or with in vitro or in vivo

Reversible alopecia

Fatigue

depletion of T cells using monoclonal antibodies.

Dry inflamed skin

Mucositis

Outcomes

Veno-occlusive disease

Disease free survival rates continue to improve and depend on

• Infections

a number of factors. Key ones are shown in Table 12.2.

Bacterial (Gram negative and positive)

Sibling matched allograft: five year disease free survival

Viral

rates for patients transplanted early in the disease are shown

Herpes zoster

Cytomegalovirus (particularly pneumonitis)

below

Fungi

Thalassaemia

90%

Candida

Aspergillus

Chronic myeloid leukaemia

65%

Atypical organisms

Acute leukaemia

55%

Pneumocystis (PCP)

Myelodysplasia

55%

Toxoplasma

Mycoplasma

Autograft: five year event free survival rates are shown below

Legionella

• Acute GvHD (allograft only)

Responsive relapsed non-Hodgkin’s

Rash

lymphoma

50%

Diarrhoea

Myeloma

25%

Jaundice

Relapsed testis cancer

30%

Blood and marrow stem cell transplantation

Procedural complications

Early complications

Allogeneic and autologous procedures are associated with

considerable morbidity and mortality. Overall, transplant-

related mortality for autologous recipients is 2-15%, for

recipients of sibling HLA matched allografts it is 15-30%, and

for recipients of allografts from volunteer, unrelated donors it

is up to 40%.

Nausea and vomiting from chemoradiotherapy is

controllable with drugs, but the widespread mucosal damage to

the gastrointestinal tract causes mucositis, which can be more

difficult to control. Oral ulceration, buccal desquamation,

oesophagitis, gastritis, abdominal pain, and diarrhoea may all

be features.

The severe myelosuppression after the transplant, together

with immune dysfunction from delayed reconstitution or graft

versus host disease, predisposes to a wide variety of potentially

fatal infections with bacterial (Gram positive and negative),

viral, fungal, and atypical organisms. Prophylactic antibiotics

Figure 12.5 Severe herpes zoster on upper arm after transplant

may reduce their incidence, but astute surveillance and prompt

intervention with intravenous antibiotics are mandatory.

Infection with the herpes simplex virus or the herpes zoster

Box 12.5 Clinical features of graft versus host disease

virus is common, and infection with the herpes zoster virus in

• Acute

particular may present with fulminant extensive lesions.

Skin rash (typically palms and soles)

The most feared viral infection after allografting, however,

Abdominal pain

is caused by cytomegalovirus. This may give rise to fulminant

Profuse diarrhoea

cytomegalovirus pneumonitis, which still has a high mortality

Jaundice (intrahepatic cholestasis)

despite newer antiviral drugs.

• Chronic

Fungal infections with Candida species are common, and

Sclerotic atrophic skin

disseminated aspergillus infection is particularly serious.

Sicca syndrome

Mucosal ulceration

Preventive measures include the use of broad spectrum

Malabsorption syndromes

antifungal agents prophylactically and the use of air filtration in

Recurrent chest infections

positive pressure isolation cubicles for patients throughout

Cholestatic jaundice

transplant.

Joint movement restriction

Graft versus host disease is classified as acute if occurring

Hyposplenic infections, e.g. Pneumococcus

within 100 days of transplantation and chronic if occurring

Myelosuppression

after that time. Acute graft versus host disease ranges from

a mild self limiting condition to a fatal disorder. The mainstay

of treatment remains immunosuppression, but severe disease

Table 12.3 New therapeutic agents in graft versus host

resistant to immunosuppressive therapy is usually fatal. Chronic

disease

graft versus host disease is associated with collagen deposition

Agent type

Mode of action

and sclerotic change in the skin, giving a wider distribution of

affected organs than the acute disease. Treatment is with

Campath 1H

Anti-lymphocyte monoclonal

immunosuppression aimed at controlling disease and

antibody—destroys T cells in vivo

ameliorating symptoms.

FK506

Powerful T cell function suppressor

Mycophenolate mofetil

Inhibits T cell function

Extracorporeal

UV inactivation of GvHD-

photopheresis

inducing lymphocytes

Follow up treatment and surveillance

For allograft recipients, immunosuppression needs careful

monitoring to avoid toxicity. Unlike transplant recipients of

Box 12.6 Late complications of transplantation

solid organs, recipients of haemopoietic transplants do not

• Infertility (both sexes)

need lifelong immunosuppression, and cyclosporin is normally

• Hypothyroidism

discontinued about six months after transplantation.

• Secondary malignancy

Prophylactic prescription for specific infections is required,

• Late sepsis due to hyposplenism

including penicillin to prevent pneumococcal sepsis secondary

• Cataracts (secondary to total body irradiation)

• Psychological disturbance

to hyposplenism, aciclovir to prevent reactivation of

the herpes simplex virus and the herpes zoster virus, and

cotrimoxazole or pentamidine to prevent infection with

Box 12.7 Low intensity v standard intensity

Pneumocystis carinii.

conditioning protocols

Regular haematological follow up is mandatory, and

psychological support from the transplant team, family, and

• Lower immediate toxicity

• ? Lower transplant related mortality overall

friends is vital for readjustment to normal life.

• ? Higher risk of relapse

Despite all the above potential complications, most patients

• Long term survival comparisons awaited

return to an active, working life without ongoing treatment.

ABC of Clinical Haematology

Recent advances

Box 12.8 Future developments in haemopoietic

transplantation

Our capability to measure miniscule amounts of residual

• Improved DNA matching techniques for volunteer

disease after transplant by polymerase chain reaction (PCR)

unrelated donors

methodology has enabled trials of therapy to prevent emerging

• Umbilical cord blood banks to expand to provide source of

relapse by the use of infusions of lymphocytes from the donor

autologus stem cells as “spare parts” for future failing organs

(DLI). Careful scheduling and dosing has treated post-allograft

• Haemopoietic stem cells to repair cardiac muscle damage

molecular relapse in CML patients and may be applicable to

from myocardial infarcts

other malignancies.

• Gene therapy

Haemophilia

The use of lower intensity conditioning protocols in

Haemoglobinopathy

allograft recipients (sometimes called mini-allos) may reduce

Cystic fibrosis

toxicity and extend the indications and age range for allografts.

The future

Haemopoietic transplantation is an exciting and rapidly

developing field. The molecular revolution has already resulted

in greatly improved DNA matching at the HLA gene loci, which

Further reading

should ensure that transplants from volunteer unrelated donors

• Atkinson K. Clinical bone marrow transplantation. Cambridge:

will be more widely applicable and more successful. The

Cambridge University Press, 2000.

haemopoietic stem cell’s property of infinite self renewal makes

• Atkinson K. The BMT data book. Cambridge: Cambridge

University Press, 1997.

it an ideal target vehicle for insertion of genes. Candidates

• Forman SJ, Blume KG, Donnall TE. Haemopoietic cell

include factor VIII gene replacement in haemophilia.

transplantation. Blackwell: Oxford, 1998.

Recent discoveries in the ability of haemopoietic stem cells

• Treleaven J, Barrett J. Bone marrow transplantation in practice.

to change into cells of many unrelated tissues such as heart,

Edinburgh: Churchill Livingstone, 1992.

brain, liver, and skin has raised the possibility of using them as

a resource to repair failing organs. Although early embryo cells

show the greatest plasticity, even stem cells from adults retain

some ability to differentiate into other human tissues.

The future therapeutic potential of haemopoietic stem cells

is enormous, but many clinical challenges remain. The next

decade is likely to see major advances in haemopoietic stem cell

I am grateful to Dr J Treleaven and Mr R Smith for providing

therapies.

photographic material.

Haematological disorders at the extremes of life

Adrian C Newland, Tyrrell G J R Evans

Infants

Box 13.1 Common causes of anaemia in newborn

infants

Anaemia in neonates

• Blood loss:—occult bleeding (fetomaternal, fetoplacental,

The haemoglobin concentration at birth is 159-191 g/l. It rises

twin to twin); obstetric accidents; internal bleeding;

transiently in the first 24 hours but then slowly falls to as low as

iatrogenic

95 g/l by nine weeks. By six months, the concentration

• Increased destruction:—immune haemolytic anaemia;

stabilises at around 125 g/l, the lower end of the adult range,

infection; haemoglobinopathies; enzymopathies

increasing towards adolescence. The normal fall in

• Decreased production:—infection; nutritional deficiencies

haemoglobin concentration seen in full term infants is

accentuated in prematurity and may fall to less than 90 g/l by

four weeks. Preterm infants are particularly prone to multiple

Table 13.1 Normal haematology values in newborn infants

nutritional deficiencies because of rapid growth. Pronounced

RBC

MCV

Nucl. RBC

anaemia may be assumed if the infant gains insufficient weight

Hb (g/l)

(

10¹²/l)

(fl)

(per ml)

or is fatigued while feeding.

Day 1

168-212

4.44-5.84

109.6-128.4

500

Week 1

150-196

4.0-5.6

93.0-131.0

Haemolytic disease in newborn infants

Week 4

111-143

3.2-4.0

92.9-109.1

Haemolytic disease in newborn infants is due to destruction of

Week 8

98-116

2.9-3.9

105.0-81.0

fetal red cells by antibodies from the mother that cross the

Week 12

104-122

3.4-4.0

80.1-95.9

placenta. The most important are antibodies to the RhD

antigen. Maternal immunisation is preventable by the

Hb, haemoglobin; RBC, red blood cells; MCV, mean cell volume;

prophylactic use of anti-D immunoglobulin, and since its

Nucl., nucleated

introduction in the 1960s the number of affected babies has

fallen dramatically. Anti-D immunoglobulin is administered to

Box 13.2 Haemolytic disease in newborn infants

non-sensitised RhD negative women, but prophylaxis may fail.

In severely affected fetuses, mortality used to be as high as

Recommendations for prophylactic anti-D immunoglobulin in

RhD negative women

40%, with only exchange transfusion available after delivery to

• After delivery if the infant is Rh positive

correct anaemia and prevent kernicterus. Intrauterine

• After abortion (therapeutic or spontaneous)

transfusion, initially via the intraperitoneal route, was

• To cover antenatal procedures (amniocentesis, chorionic

introduced to prevent problems in the fetus. However, it was

villus sampling)

the development in the early 1980s of intravascular blood

• After threatened abortion or miscarriage

transfusion using fetoscopy into the umbilical artery that

• Antenatally at 28 and 34 weeks (not yet universal)

dramatically improved survival. Hydrops can be readily reversed

Reasons for failure of prophylaxis

• Failure of administration (commonest cause)

in utero, and even in the most severe group the survival rate

• Inadequate dosage (routine Kleihauer tests should be

has been 85%.

performed)

• Earlier sensitisation that may not be detectable at birth

Anaemia associated with infection

• Poor injection technique (should be deep intramuscular)

Cytomegalovirus, rubella, toxoplasmosis, and more rarely

congenital syphilis may be associated with anaemia, due either

to haemolysis or to bone marrow suppression. More recently,

Box 13.3 HIV infection

human parvovirus B19 has been identified as a cause of

• HIV may produce a chronic multisystem disease in children

anaemia and fetal damage. In early pregnancy maternal

• Perinatal transmission of the virus from an infected woman

infection may lead to spontaneous abortion, but in later

is the primary route of exposure to the fetus (20-40% of

pregnancy it may lead to selective depression of erythropoiesis

pregnancies)

with profound anaemia and the development of hydrops. It

• Thrombocytopenia occurs in up to 15% of children with

may also induce an aplastic crisis or chronic haemolysis in

HIV infection

• Anaemia is also common, occurring early, usually with the

normal children but is a major problem in those with an

normocytic, normochromic features of chronic disease

underlying haemoglobinopathy.

• Leucopenia and lymphopenia are also seen, in which the

Malaria is a major health hazard worldwide, and easier travel

bone marrow shows non-specific features of chronic

to endemic areas has increased the problem. Inadequate or

infection

non-existent prophylaxis has led to an increase in cases over the

past few years; unsuspected infection in neonates, usually caught

from the mother, may be associated with a high mortality.

The haemoglobinopathies

Thalassaemia major is an inherited haemoglobin disorder

caused by reduction in globin chain synthesis. It affects

primarily people from the Indian subcontinent and of

Mediterranean origin. It presents during the first year of life

after the switch from fetal to adult haemoglobin. If production

of the latter is reduced, anaemia occurs. The infant presents

ABC of Clinical Haematology

with failure to thrive, poor weight gain, feeding problems, and

irritability. The blood appearances are typical, with severe

anaemia associated with microcytosis and hypochromia with

pronounced morphological change in the red cells. The infant

will be dependent on transfusions unless bone marrow

transplantation is feasible. The carrier state (thalassaemia

minor or thalassaemia trait) mimics iron deficiency, from which

it must be differentiated.

Thalassaemia presents a similar picture, and the

condition is a common cause of stillbirth in South East Asia.

Sickle cell disease

Sickle cell disease is caused by a structural abnormality of the

Figure 13.1 Peripheral blood of patient with Hb H disease showing pale

chain and is associated with a steady state haemoglobin of

red cells (hypochromia) with variation in size and shape

50-110 g/l. In homozygous sickle cell disease the haemoglobin

(anisopoikilocytosis)

forms crystals, distorting the red blood cells into a rigid sickle

cell shape. It is these sickle cells that block the

microvasculature, causing sickle cell crises. Mortality and

Table 13.2 Features of thalassaemia

morbidity are increased at all ages, with the peak incidence of

death at age 1-3 years. Sickle cell crises are precipitated by

Haematological

infection, hypoxia, dehydration, cold, and exhaustion and are

Syndrome

abnormalities

Diagnosis

particularly common in adverse environmental or poor

Silent carrier

No anaemia or

1-2% Hb Bart’s^†

socioeconomic conditions. In infants, crises present with

microcytosis

the clinical problems of infection, splenic sequestration,

Thalassaemia trait

Mild anaemia and

3-10% Hb Bart’s

and dactylitis. Towards the end of the first year, painful

)

microcytosis

vaso-occlusive crises are more common, and pneumococcal

Hb H disease

Moderate microcytic,

20-40% Hb Bart’s

septicaemia related to splenic dysfunction is particularly

(-/-

)

hypochromic

apparent.

haemolytic anaemia

Genetic counselling and prenatal diagnosis have made an

Hb Bart’s hydrops

Severe microcytic

80% Hb Bart’s,

important contribution to reducing the number of affected

syndrome (--/--)

hypochromic

20% Hb H^‡

anaemia (lethal)

children in countries with a comprehensive screening

programme.

*Where

/ is normal (that is, 4 genes) and - represents

deletion of one gene on a chromosome

^†Bart’s

4 tetramers

Disorders of haemostasis

^‡Hb H

4 tetramers

Deficiencies of clotting factor VIII (haemophilia A) or

factor IX (haemophilia B or Christmas disease) may present

symptomatically in the first days of life, with spontaneous

Antenatal screening for carrier detection of sickle cell

bleeding. Bleeding from the cord or intracranial haemorrhage,

disease (with subsequent study of the partners of positive

however, are fortunately rare. Severe bleeding usually occurs at,

women) should be carried out so that prenatal diagnosis

for example, circumcision or when mobility increases. Both

can be offered

disorders of coagulation affect 1 in 10 000 of the population.

They are X linked and clinically indistinguishable. The

diagnosis may be suspected from the family history and can be

confirmed antenatally.

In up to 30% of all new cases patients will have no family

history of coagulation disorders, and such cases are

therefore new mutations

Thrombocytopenia

Healthy infants have a platelet count in the adult range

(150-400

10⁹/l). Thrombocytopenia is the most common

Box 13.4 Common causes of thrombocytopenia

haemostatic abnormality in newborn infants, occurring in

up to a quarter of babies admitted to neonatal intensive

• Immune mediated

treatment units. Asphyxia at birth, infection, and disseminated

Neonatal alloimmune thrombocytopenia

Maternal immune thrombocytopenia purpura

intravascular coagulation are the most common causes of

Drug-induced

thrombocytopenia. It may also occur after exchange

• Infection

transfusion. Platelet transfusions should be given to any infant

Viral—eg cytomegalovirus, HIV, rubella

whose count is

2010⁹/l.

Toxoplasmosis

Maternal autoimmune thrombocytopenia may be associated

• Post exchange transfusion

with neonatal thrombocytopenia because of placental transfer

• Disorders of haemostasis

Disseminated intravascular coagulation

of antiplatelet antibodies. Fetal platelet counts rarely drop

Maternal pre-eclampsia

below 50

10⁹/l, and intracranial haemorrhage is rare either

Rhesus isoimmunisation

prenatally or at birth. However, the count may fall in the first

Hypothermia, hypoxia

few days of life, and treatment may be needed at this stage.

Type IIB von Willebrand’s disease

There are no reliable predictors of severe

• Liver disease

thrombocytopenia. Treatment includes platelet transfusions

• Giant haemangioma

• Hereditary thrombocytopenia

and corticosteroids, but intravenous immunoglobulin is safe

• Marrow infiltration

and effective in over 80% of infants.

Haematological disorders at the extremes of life

Neonatal alloimmune thrombocytopenia is associated with

170

severe thrombocytopenia, and intracranial haemorrhage is seen

Intravenous

150

in up to 15% of infants. Maternal platelet counts are normal,

immunoglobulin

and maternal alloantibodies are directed against paternally

130

derived antigens on the infant’s platelets (usually HPA-1). In at

110

risk pregnancies fetal blood sampling by cordocentesis should

be used to confirm the HPA-1 status. Treatment relies on

platelet transfusions in utero, but high dose intravenous

immunoglobulin may be of some benefit.

Vitamin K deficiency

26 28 30

11 13 15 17 19 21

23 25 27

Haemorrhagic disease in newborn infants may be associated

January

February

March

Delivery

with vitamin K deficiency. It may be seen in otherwise healthy

term infants, especially if they are being breast fed. The

Figure 13.2 Response of neonate to intravenous immunoglobulin with

deficiency may be precipitated if the mother is taking

thrombocytopenia secondary to maternal immune thrombocytopenic

anticonvulsant drugs or warfarin. It may present soon after

birth with generalised bruising and internal bleeding, or as late

reserved.

as age one month.

Treatment is now aimed at prevention by administering

vitamin K prophylaxis, although some controversy remains

Table 13.3 Haemorrhagic disease of newborn infants

about whether this should be given orally or parenterally.

Type

Clinical signs

Causes

Early (within

Severe bleeding,

Mother receiving drugs

Elderly people

24 hours)

often internal

affecting vitamin K—eg

anticonvulsant

Haemoglobin concentration gradually declines from the

(phenytoin), warfarin,

age 60 years, with a more rapid fall over the age of 70. The fall

antituberculosis

is accompanied, however, by a widening of the reference

drugs (rifampicin,

range, such that age dependent ranges are of little value in

isoniazid)

individuals.

Classic

Bruising or bleeding

Breast feeding, full

Concentration should be considered in association with the

(2-5 days)

from gastrointestinal

term

clinical history. In older patients the lower end of the normal

tract or after

range should be reduced to 110 g/l.

circumcision

Delayed (up to

Intracranial

Prolonged breast

1 month)

haemorrhage,

feeding without

Iron deficiency anaemias

common

prophylaxis;

Between 10 and 20% of elderly people will be anaemic, usually

chronic diarrhoea,

with iron deficiency. In many this will be nutritional, owing to

malabsorption, or oral

difficulties in obtaining and eating food, for both medical and

antibiotics

social reasons. The possibility of an occult gastrointestinal

malignancy (for example, caecal carcinoma) leading to iron

deficiency anaemia should be considered. Aspirin or non-

steroidal anti-inflammatory drugs leading to occult

gastrointestinal blood loss may also contribute. The problem

may also be exacerbated in elderly people as gastric atrophy

may occur, leading to poor absorption of iron supplements.

Box 13.5 Clinical associations in iron deficiency

Symptoms: lethargy, lassitude, reduced activity; shortness of

breath; angina on effort; intermittent claudication

Signs: pallor, peripheral oedema; brittle nails, koilonychia;

glossitis; stomatitis

Other gastrointestinal findings: oesophageal web; atrophic

gastritis; subtotal villous atrophy with malabsorption

Oral supplements are usually well tolerated. They should

be continued for three months after the haemoglobin

concentration has returned to normal, to replenish the iron

stores.

Megaloblastic anaemia

Folic acid deficiency also occurs readily in those who eat

poorly and can be easily corrected by supplements. Pernicious

Figure 13.3 Megaloblastic anaemia: peripheral blood (top) showing

anaemia due to vitamin B₁₂ deficiency also occurs in middle

macrocytes, tear drops, and multisegmented neutrophils; megaloblastic

and later life and may be associated with weakness and loss of

bone marrow (bottom) showing megaloblasts, giant metamyelocytes, and

sensation. Vitamin B₁₂

stores normally fall in older people, and

hypersegmented neutrophil

ABC of Clinical Haematology

deficiency should always be considered with those developing

dementia.

Care must be taken to differentiate megaloblastic anaemia

from myelodysplastic syndrome, which may be associated with

a refractory macrocytic anaemia. Serum concentrations of

vitamin B₁₂, folate, and red cell folate should be measured, and

occasionally a bone marrow examination may be indicated.

The importance of identifying any deficiency anaemia is

that, although the effects may be relatively mild initially, they

can progress and severely incapacitate a previously active

elderly person. The deficiencies can be easily reversed, and

supplements should be continued for as long as the underlying

problem remains.

Box 13.6 Findings in anaemia of chronic disease

• Mild normocytic or microcytic anaemia

Anaemia of chronic disease

• Low serum iron concentration and iron binding capacity

Any prolonged illness such as infection, malignant disease,

• Reduced transferrin saturation

renal disease, or connective tissue disorder may be

• Normal or raised serum ferritin concentration

accompanied by a moderate fall in the haemoglobin

• Increased iron in reticuloendothelial stores—eg bone

concentration. This seldom drops below 90-100 g/l, and it is

marrow

• Defective iron transfer to red cell precursors

typically normocytic and normochromic. Haematinics will not

• Iron reduced in red cell precursors

increase the haemoglobin concentration, which may improve

• Increased red cell protoporphyrin

only after treatment of the underlying condition. This

condition may not always be apparent, and a general screen

may be needed for underlying malignancy or systemic disease.

Malignancies

Box 13.7 Screening tests in anaemia of chronic disease^*

Most forms of malignancy are more common in elderly people

• Review of peripheral blood film

than in the rest of the population. The myelodysplastic

• Erythrocyte sedimentation rate

syndromes and chronic lymphocytic leukaemia are frequently

• Liver and renal screen

found incidentally, and their diagnosis does not necessarily

• Chest radiograph

indicate the need for treatment. Each patient must be

• Autoantibody screen

considered individually so that the possible benefits of

• Urine analysis

treatment can be balanced against side effects and considered

• Thyroid function studies

• Tumour markers

in the light of any improvement in the quality of life.

Immunoglobulins (myeloma)

Prostate specific antigen

Fetoprotein (liver)

Further reading

Carcinoembryonic antigen (gastrointestinal)

• Hann IM, Gibson BES, Letsky EA, eds. Fetal and neonatal

* After history and clinical examination.

haematology. London: Baillière Tindall, 1991.

• Lilleyman JS, Hann IM, eds. Pediatric hematology. New York:

Churchill Livingstone, 1992.

• Spiers ASD. Management of the chronic leukemias: special

considerations in the elderly patient. Part 1. Chronic

Figure 13.2 is adapted with permission from Newland et al. (N Engl

lymphocytic leukemias. Hematology 2001;6:291-314.

J Med 1984;310:261-2).

Haematological emergencies

Drew Provan

Patients with both malignant and non-malignant

haematological disease may present with dramatic and often

life threatening complications of their diseases. General

physicians must be able to recognise and start basic treatment,

which may be life saving, in patients presenting with

haematological emergencies.

This chapter deals with five of the most common

emergencies encountered by haematologists. Although none of

these conditions is seen often in day to day clinical practice,

recognition of the underlying disease processes is important in

determining the likely cause of the abnormalities and is helpful

in determining the specific treatment needed.

Figure 14.1 Fundal changes in patient with hyperviscosity (newly

diagnosed myeloma with IgA concentration 50 g/l)

Hyperviscosity syndrome

Box 14.1 Causes of hyperviscosity

This may be caused by several haematological conditions.

• Myeloma (especially IgA)

• Waldenström’s macroglobulinaemia (IgM paraprotein)

Blood viscosity is a function of the concentration and

• Polycythaemia

composition of its components. A marked increase in plasma

• High white cell count (hyperleucocytosis)

proteins (for example, monoclonal immunoglobulin in

myeloma) or cellular constituents (for example, white blood

cells in acute leukaemia) will raise the overall blood viscosity.

Box 14.2 Symptoms and signs of hyperviscosity

This leads to sludging of the microcirculation and a variety of

clinical manifestations. Hyperviscosity may present insidiously

• Mild headache

or acutely with neurological symptoms and signs.

• Neurological disturbance

Ataxia

Blood viscosity will often be more than four times the

Nystagmus

normal viscosity before symptoms occur. Patients with chronic

Vertigo

disorders such as polycythaemia and myeloma are often

Confusion

physiologically well compensated for the degree of

Changes in mental state

hyperviscosity and may complain only of mild headaches. In

Coma

contrast, patients with acute leukaemia and a high white cell

• Visual disturbance

Blurring of vision

count may present in extremis; they become hypoxic from

Dilatation and segmentation of retinal veins

pulmonary involvement and are often obtunded, with a variety

“Sausage” appearance of retinal veins

of neurological signs. Prompt treatment is needed to prevent

Risk of central retinal vein occlusion

permanent deficits. Elderly patients with impaired left

• Genitourinary or gastrointestinal bleeding

ventricular function may experience decompensation due to

their hyperviscosity, resulting in increasing congestive cardiac

failure.

The definitive treatment of patients with hyperviscosity

is dependent on the underlying pathology. For patients

presenting with acute leukaemia, vigorous intravenous

hydration and intensive chemotherapy often results in

a rapid reduction in the white cell count. Leukapheresis

may be used as an interim measure until chemotherapy exerts

its full effect. For patients with myeloma or Waldenström’s

macroglobulinaemia (a low grade lymphoma characterised by

production of monoclonal IgM, most of which is intravascular)

plasmapheresis effectively reduces the paraprotein

concentration. Plasmapheresis is more effective in reducing the

Figure 14.2 Blood film in patient with hyperviscosity due to

hyperleucocytosis (4 year old child with newly diagnosed acute

level of IgM than IgG paraprotein since the former is

lymphoblastic leukaemia; white cell count 200

10⁹/l)

predominantly intravascular while IgG is mainly extravascular.

Plasmapheresis may be used both for acute attacks and

long term—for example, as palliative treatment for

Sickle cell crisis

patients resistant to, or unable to tolerate, chemotherapy

The sickling disorders (Hb SS, Hb SC, Hb S/ thalassaemia,

and Hb SD) are inherited structural haemoglobin variants.

Homozygous Hb SS in particular is associated with several

complications, including recurrent vaso-occlusive crises, leg

ulcers, renal impairment, hyposplenism, and retinopathy.

ABC of Clinical Haematology

Box 14.3 Sickle cell crises

Sickling

• Vaso-occlusive: In any tissue but especially bones, chest, and

abdomen (eg splenic infracts); in cerebral vessels, leading to

stroke

•

Aplastic: In parvovirus B19 infection

• Sequestration: Particularly in infants and young children;

massive pooling of red cells in spleen and other organs,

leading to precipitous drop in haemoglobin

•

Haemolytic: Further reduction in life span of red cells,

leading to worsening anaemia and features of haemolysis

Acidosis

Hypoxia

•

Chest syndrome: Pleuritic pain and fever may mimic

pneumonia or pulmonary embolism; progressive respiratory

failure

Sickle cell crises include vaso-occlusive, aplastic,

Figure 14.3 Vicious cycle in sickle cell crisis

sequestration, and haemolytic episodes. The chest syndrome

and the girdle syndrome are more severe forms of crisis

associated with higher morbidity and mortality.

Crises may be precipitated by dehydration or infection; in

many cases no obvious precipitant is found.

Box 14.4 Treatment of sickle cell crises

The aim of treatment is to break the vicious cycle of

• Vigorous intravenous hydration

sickling: sickling results in hypoxia and acidosis, which in turn

• Adequate analgesia—for example, intravenous opiates

precipitate further sickling. This is exacerbated by dehydration,

• Broad spectrum antibiotics

and a high fluid intake (70 ml/kg/24 h) is the cornerstone of

• Oxygen therapy

management.

• Consider exchange blood transfusion

Also imperative in managing sickle cell crises is adequate

pain relief—opiates, by continuous subcutaneous or intravenous

infusions, may be needed. Arterial blood gas pressures should

be performed and oxygen therapy prescribed if hypoxia is

confirmed. It should be remembered that sickle cell patients are

functionally asplenic and that infection is a common precipitant

of crises. Broad spectrum antibiotics should be started while

waiting for the results of blood and urine cultures.

It is important to recognise the patients who need urgent

exchange transfusion to reduce the level of Hb S to below 30%.

Transfusion should be started promptly if the patient has a

severe chest syndrome (with pronounced hypoxia), has had a

cardiovascular accident, or has priapism.

Spinal cord compression

Some patients may present at the haematology clinic with

metastatic tumour deposits—for example, lymphoma or

plasmacytoma—resulting in cord compression. Commonly,

overt cord compression is preceded by signs consistent with

root compression, with pain in the affected dermatome. Most

patients with cord compression complain of pain—it is often

constant and easily confused with that of pain due to

degenerative disease. Often it is not until more overt

neurological signs are manifested that a diagnosis of cord

Figure 14.4 Magnetic resonance image showing spinal cord compression

compression is considered.

The neurological signs accompanying cord compression vary

according to both the rapidity of development of compression

and the area of cord affected. Acute lesions often result in

hypotonia and weakness, whereas chronic lesions are more

Box 14.5 Symptoms and signs of cord compression

often associated with the classic upper motor neurone signs of

• Back pain

hypertonia and hyper-reflexia. The associated sensory loss is

• Weakness in legs

defined by the site of the lesion, but hyperaesthesia may be seen

• Upper motor neurone and sensory signs

in the dermatome at the level of the lesion. More lateral lesions

• Loss of sphincter control (bowels/bladder)

may result in a dissociative sensory loss—that is, ipsilateral loss

of joint position sense and proprioception with contralateral

loss of pain and temperature. Bladder and bowel disturbances

often occur late, with the exception of the cauda equina

compression syndrome, in which they are an early feature.

Neurological advice should be obtained as in some cases

If cord compression is suspected the patient should be

surgical decompression may allow recovery of function

investigated with plain spinal radiography, which may show

Haematological emergencies

evidence of lytic lesions (as, for example, in myeloma). The

Box 14.6 Causes of acute disseminated intravascular

definitive investigation is magnetic resonance imaging to

coagulation

delineate the level of the lesion and to help plan further

• Infection: Especially Gram negative infections, endotoxic

treatment.

shock

In a patient presenting de novo with cord compression

• Obstetric: Placental abruption, intrauterine fetal death,

further investigations (protein electrophoresis, measurement of

severe pre-eclampsia or eclampsia, amniotic fluid embolism

prostatic specific antigen and other tumour markers, and chest

• Trauma: Especially head injury, burns

radiography) are needed to elucidate the underlying cause. A

• Malignancy: Carcinoma of prostate, lung, pancreas, ovary,

formal biopsy of the lesion may be needed to determine the

and gastrointestinal tract

• Miscellaneous: Transfusion with incompatible blood group,

underlying condition.

drug reactions, hypothermia, venomous snake bite,

In an acute presentation high dose dexamethasone (for

transplant rejection

example, 4 mg four times daily) is given. Further management

• Vascular: Aortic aneurysm, giant haemangioma

depends on the underlying cause, but often a combination of

chemotherapy and radiotherapy is given.

Box 14.7 Initial management of disseminated

intravascular coagulation

Disseminated intravascular

• Treat as for severe bleeding/shock

coagulation

• Establish intravenous access (large bore cannula)

• Restore circulating volume—with, for example, crystalloids

Disseminated intravascular coagulation describes the syndrome

• Administer fresh frozen plasma and cryoprecipitate and

of widespread intravascular coagulation induced by blood

regularly monitor full blood count, prothrombin time, and

procoagulants either introduced into or produced in the

activated partial thromboplastin time

bloodstream. These coagulant proteins overcome the normal

• Consider giving platelet transfusion

physiological anticoagulant mechanisms. The overall result,

• Remove the underlying cause

irrespective of cause, is widespread tissue ischaemia (due to clot

formation, thrombi) and bleeding (due to consumption of

clotting factors, platelets, and the production of breakdown

Box 14.8 Clinical features of disseminated intravascular

products that further inhibit the coagulation pathway).

coagulation

The diagnosis of disseminated intravascular coagulation is

Bleeding

initially clinical and is confirmed by various blood tests. There

• Spontaneous bruising

are many causes of disseminated intravascular coagulation,

• Petechiae

• Prolonged bleeding from venepuncture sites,

including obstetric emergencies, infections, neoplasms, trauma,

arterial lines, etc.

and vascular disorders.

• Bleeding into gastrointestinal tract or lungs

Treatment is primarily directed at the underlying cause—

• Secondary bleeding after surgery

for example, the use of antibiotics when infection is suspected,

• Coma (intracerebral bleeding)

or removal of fetus and placenta with placental abruption or

Clotting

retained dead fetus syndrome. Disseminated intravascular

• Acute renal failure (ischaemia of renal cortex)

coagulation generally resolves fairly quickly after removal of the

• Venous thromboembolism

underlying cause.

• Skin necrosis or gangrene

• Liver failure (due to infection and hypotension)

Interim supportive measures, such as intravenous hydration

• Coma (cerebral infarction)

and oxygen therapy, are important. Correction of the

Shock

coagulopathy entails the use of fresh frozen plasma,

• Due to underlying disease together with disseminated

cryoprecipitate, and platelet transfusion. No uniform protocol

intravascular coagulation

exists for transfusing blood and blood products. Instead, for

Central nervous system

each patient the quantity of blood product used is decided

• Transient neurological symptoms and signs

after clinical evaluation and serial coagulation assays.

• Coma

The use of intravenous heparin to treat disseminated

• Delirium

intravascular coagulation remains controversial. Some evidence

Lungs

• Transient hypoxaemia

supports the value of heparin in the management of acute

• Pulmonary haemorrhage

promyelocytic leukaemia, the dead fetus syndrome, and aortic

• Adult respiratory distress syndrome

aneurysm before resection. For other causes of disseminated

intravascular coagulation the use of heparin is more uncertain

and may actually worsen the bleeding.

Table 14.1 Main investigations* for disseminated

intravascular coagulation

Infection in patients with

Investigation

Positive result

impaired immunity

Full blood count

Decreased platelet count

Patients with a variety of haematological diseases are

Prothrombin time

Increased

immunocompromised due to either their underlying disease or

Activated partial thromboplastin

Increased

the treatment required for the condition. For example, patients

time

with myeloma often present with recurrent infection as a result

Fibrinogen

Decreased

of the reduction in normal immunoglobulin concentrations

Fibrin degradation products/

Increased

D dimers

associated with the paraproteinaemia. This susceptibility is

compounded by the use of combination chemotherapy, which

*Other investigations: urea and electrolytes, liver function tests,

may render patients neutropenic.

blood cultures, pulse oximetry (oxygen saturation)

ABC of Clinical Haematology

Figure 14.5 Herpes zoster virus affecting the ophthalmic division of the

trigeminal nerve in patient with chronic lymphocytic leukaemia

Box 14.9 Risks of infection in patients with no spleen

or hypofunctioning spleen

• With encapsulated organisms—for example, Streptococcus

pneumoniae (60%), Haemophilus influenzae type b. Neisseria

meningitidis

•

Less commonly—Escherichia coli, malaria, babesiosis,

Capnocytophaga canimorsus

Figure 14.6 Card carried by patients with no spleen or hypofunctioning

spleen

Several haematological disorders are now routinely treated

in outpatient clinics with aggressive chemotherapy, so some

patients in the community may be neutropenic as a result of

Box 14.10 Recommendations for patients with no

this. Patients are educated to seek medical advice immediately

spleen or hypofunctioning spleen*

if they develop any infection, since Gram negative septicaemia

may lead rapidly to death. For patients receiving intensive

• Pneumococcal vaccine (Pneumovax II) 0.5 ml—two weeks

before splenectomy or as soon as possible after splenectomy

chemotherapy presenting with fever while neutropenic, broad

(for example, if emergency splenectomy is performed);

spectrum antibiotics should be started immediately. The choice

reimmunise every 5-10 years

of antibiotics depends on local microbiological advice in the

• H influenzae type b (Hib) vaccine 0.5 ml

light of the sensitivities of the micro-organisms in the region.

• Meningococcal polysaccharide vaccine for N meningitidis

Patients with chronic lymphocytic leukaemia often have

type A and C 0.5 ml

recurrent infection in the absence of neutropenia, because of

• Penicillin as prophylaxis (250 mg twice daily—for life)

the accompanying hypogammaglobulinaemia seen in this

The three vaccines (subcutaneous or intramuscular) may be

disorder. Frequent courses of antibiotics are often required.

given at same time, but different sites should be used

The role of regular intravenous immunoglobulin infusions to

*Based on the guidelines for the prevention and treatment of

“boost” their immunity is debatable. Patients with chronic

infection in patients with an absent or dysfunctional spleen,

BMJ 1996;312:430-4.

lymphocytic leukaemia may develop severe recurrent herpes

zoster infections. Prompt treatment with aciclovir should always

be given at the first suspicion of any herpetic lesions

developing, and hospital referral for intravenous antibiotics

and aciclovir should be considered if the lesions are not

Further reading

confined to a single dermatome or are in a delicate area—for

• Beck JR, Quinn BM, Meier FA, Rawnsley HM. Hyperviscosity

example, ophthalmic division of the trigeminal nerve.

syndrome in paraproteinemia. Managed by plasma exchange;

Patients who are functionally or anatomically asplenic are at

monitored by serum tests. Transfusion 1982;22(1):51-3.

high risk of infection with encapsulated organisms, especially

• Davies SC, Oni L. Management of patients with sickle cell

Streptococcus pneumoniae.

disease. BMJ 1997;315(7109):656-60.

Penicillin prophylaxis and immunisation reduces the

• Gopal V, Bisno AL. Fulminant pneumococcal infections in

incidence of these infections but does not abolish the risk

“normal” asplenic hosts. Arch Intern Med 1977;137(11):1526-30.

completely. If any of these patients becomes acutely unwell the

• Working Party of the British Committee for Standards in

Haematology Clinical Haematology Task Force. Guidelines for

prompt administration of 1200 mg benzylpenicillin (if no

the prevention and treatment of infection in patients with an

history of allergy to penicillin) and prompt referral for further

absent or dysfunctional spleen. BMJ 1996;312(7028):430-4.

treatment may be life saving.

• Levi M, ten Cate H, van der Poll T, van Deventer SJ.

Pathogenesis of disseminated intravascular coagulation in sepsis.

JAMA 1993;270(8):975-9.

• Torres J, Bisno AL. Hyposplenism and pneumococcemia.

Dr Ken Tung, consultant radiologist, Southampton University

Visualization of Diplococcus pneumoniae in the peripheral blood

Hospitals Trust, provided the magnetic resonance image in

smear. Am J Med 1973;55(6):851-5.

Figure 14.4. Figure 14.5, showing herpes zoster virus, is from

• Winkelstein A, Jordan PS. Immune deficiencies in chronic

Clinical haematology—a postgraduate exam companion by D Provan,

lymphocytic leukemia and multiple myeloma. Clin Rev Allerg

A Amos and AG Smith. Reprinted by permission of Elsevier

1992;10(1-2):39-58.

Science.

The future of haematology: the impact of

molecular biology and gene therapy

Adele K Fielding, Stephen J Russell

This chapter will assess the impact of advances in science and

Box 15.1 The future of haematology—diagnosis and

technology on the practice of haematology and attempt to

treatment

predict how haematology might change further over the next

10 to 15 years.

Diagnosis

• Increasing automation giving quicker and more reliable

The major advances in scientific thought and technological

results—eg automated cross matching; automated diagnostic

development that have already changed the practice of modern

polymerase chain reaction

haematology are likely to affect both laboratory diagnosis and

• More DNA/RNA based diagnosis, allowing increased

treatment in the future. The first draft of the sequence of the

diagnostic precision—eg precise definition of genetic

human genome has now been published and “genomics” has

abnormalities; diagnosis with polymerase chain reaction

mushroomed. The first clinical study in which gene therapy

• More “near patient” testing, allowing rapid screening—eg

haemoglobinometers, monitoring of anticoagulant

provided clear clinical benefit to patients has also been

treatment

reported. Another very exciting development which may

Treatment

ultimately impact the practice of haematology is the discovery

• New drugs—eg tailored to molecular abnormalities

of the plasticity of post-natal stem cells. The identification of

• New biological agents—eg viruses and viral vectors,

post-natal progenitor cells which can, ex vivo, be expanded and

monoclonal antibodies

differentiated into many different cell types, may pave the way

• Transplantation across tissue barriers—eg cord blood

for treatment of genetic disorders of many kinds. While the

transplantation

debate about the ethical implications in the use of embryonic

• Blood substitutes—eg recombinant haemoglobin

stem cells continues in many countries, post-natal stem cells

• Gene therapy—probably for many haematological disorders

may now offer a realistic and non-controversial alternative.

The chapter begins with an introduction to genomics and

gene therapy, both of which are likely to have a role in most

Table 15.1 Gene therapy strategies

areas of haematological practice in the future. Three specific

Strategy

Potential application

areas of haematology are then examined—haemoglobinopathy,

Corrective replacement

Sickle cell disease—to replace the

haemophilia, and haematological malignancy—in each of

point mutation that causes the

which important innovations could be expected to change

substitution of valine for glutamine on

clinical practice.

the sixth amino acid residue of

Both diagnostically and therapeutically, the identification of

the globin chain

the molecular pathology of the underlying disorder will

Corrective gene addition

Haemophilia—to introduce a gene for

continue to steer the future. The ability to make more accurate

missing coagulation protein

diagnoses in haematology is only just beginning to result in

Corrective antisense

Low grade non-Hodgkin’s lymphoma

improved treatments. Careful clinical studies with well-designed

treatment

(NHL)—to introduce antisense

oligonucleotides, preventing BCL2

correlative science that aims to ask and answer specific

overexpression, which is responsible

questions should remain the basis on which novel

for the failure of the lymphoma cells to

developments make their impact on routine practice.

undergo apoptosis

Pharmacological

Continuous production of interferon

alfa, erythropoietin, or other

therapeutic proteins

Gene therapy

Cytotoxic

Leukaemia—targeted delivery of

The term gene therapy is applied to any manoeuvre in

cytotoxic proteins

which genes or genetically modified cells are introduced into

Prophylactic

Chemoprotection—drug resistance

a patient for therapeutic benefit. Gene therapy is still in

genes introduced into haemopoietic

stem cells, conferring resistant

its infancy, and despite the potential of the approach,

phenotype, thus protecting against

clinical benefit has only recently been demonstrated.

chemotherapeutic agents

Successful gene therapy depends on the availability of

Immunostimulatory

Idiotypic vaccination—in B cell

reliable methods for delivering a gene into the nuclei of

tumours such as NHL and myeloma

selected target cells and subsequently ensuring the regulation

the variable region sequences of

of gene expression. Haematological cells are readily accessible

the surface immunoglobulin of the

for manipulation and so can be genetically modified outside

tumour cell provide a tumour specific

antigen against which an individualised

the body and re-infused. The aim in the future, however, will be

vaccine for each patient can be

to modify the target cells without first removing them from the

produced

patient. Genes that are to be delivered to cells must first be

Replicating virus

Oncolytic viruses may be used

inserted into plasmids. These small circular molecules of

therapy

to directly kill transformed cells

double stranded DNA derived from bacteria can then be used

to transfer therapeutic genes to cells by physical methods or by

insertion into recombinant viruses.

Whichever vector system is used, the barriers through which

the therapeutic genes must be transported to reach their

ABC of Clinical Haematology

Ex vivo

In vivo

Target cell

Access

Nucleus

Binding

DNA

Cytoplasmic

Bone marrow

Genetically

transport

cells are

modified cells

Expression

removed

are reinfused

from patient

Function

Therapeutic genes are

administered to patient;

Figure 15.2 ABC of gene therapy—A vector must be able to access the

in vivo targeting allows

cells to be transduced and bind and penetrate the membrane of the

target cell. Once inside the nucleus, the exogenous DNA must be

them to integrate directly

Therapeutic genes are

integrated into the cellular genome if stable expression is required. Gene

into haemopoietic cells

transfected into cells

expression must be at a high enough level and sufficiently regulated for

clinical benefit

Figure 15.1 Ex vivo and in vivo gene transfer strategies

destination are the same. Many viral and non-viral vector

systems are being developed to try to achieve the steps outlined

here, and it is often difficult to choose the most appropriate

vector for a particular application.

For gene therapy applications, where it is crucial to achieve

gene expression in the progeny of the target (modified) cells, it

is important to use a vector that stably inserts its genes into the

chromosome of the host cell, and retrovirus vectors are the

most suitable for this purpose. For direct in vivo gene delivery,

vector attachment to a specific target cell is a vital additional

requirement. Such vector targeting is at last beginning to look

like a realistic possibility.

Genomics

Genomics can be defined as “the systematic study of all the

genes of an organism”. Recently, the number of genes in the

human genome has been estimated at being between 30 000

and 40 000—many less than previously thought. The function

of most of these genes currently remains unknown, although it

is likely that this will not always be the case. It is now possible to

obtain a profile of which genes are expressed in a given cell or

tissue under defined conditions by means of cDNA arrays,

which are thousands of unique DNA probes robotically

deposited onto a solid matrix or “DNA chip”. To profile gene

expression in the tissue of interest, messenger RNA is isolated,

copied into DNA labelled with a fluorescent dye and then used

to probe the DNA chip to obtain an expression profile. A huge

amount of data can be gathered in this manner, but to turn this

into interpretable information requires considerable

computing capacity—the processing and interpretation of data

so obtained is known as bio-informatics. Profiling gene

expression in various conditions may be useful diagnostically

and may ultimately yield considerable information about the

function of hitherto unidentified genes. Proteomics, the

systematic study of all the proteins in a cell, tissue or organ,

may ultimately be more useful than genomics. However, the

technical hurdles are much greater, not least due to the vast

number and complexity of the proteins to be studied.

Improved methods for gel-separation of proteins and improved

image analysis are likely to make study of the proteome

a legitimate goal.

The future of haematology: the impact of molecular biology and gene therapy

ALL

AML

C-myb(U22376)

Proteasome iota (X59417)

MB-1 (U05259)

Cyclin D3 (M92287)

Myosin light chain (M31211)

RbAp48 (X74262)

SNF2 (D26156)

HkrT-1 (S50223)

E2A (M31523)

Inducible protein (L47738)

Dynein light chain (U32944)

Topoisomerase II β (Z15115)

IRF2 (X15949)

TFIIEβ (X63469)

Acyl-Coenzyme A dehydrogenase (M91432)

SNF2 (U29175)

(Ca²⁺)-ATPase (Z69881)

SRP9 (U20998)

MCM3 (D38073)

Deoxyphypusine synthase (U26266)

Op 18 (M31303)

Rabaptin-5 (Y08612)

Heterochromatin protein p25 (U35451)

IL-7 receptor (M29696)

Adenosine deaminase (M13792)

Fumarylacetoacetate (M55150)

Zyxin (X95735)

LTC4 synthase (U50136)

LYN (M16038)

Hox A9 (U82759)

CD33 (M23197)

Adipsin (M84526)

Leptin receptor (Y12670)

Cystatin C (M27891)

Proteoglycan 1 (X17042)

IL-8 precursor (Y00787)

Azurocidin (M96326)

p62 (U46751)

CyP3 (M80254)

MCL1 (L08254)

ATPase (M62762)

IL-8 (M28130)

Cathepsin D (M63138)

Lectin (M57710)

MAD-3 (M69043)

CD11c (M81695)

Ebp72 (X85116)

Lysozyme (M19045)

Properdin (M83652)

Catalase (X04085)

-3

-2.5

-2

-1.5

-1

-0.5

0.5

1.5

2.5

Low

Normalised expression

High

Figure 15.3

Microarray technology allows analysis of thousands of different genes simultaneously

Haemoglobinopathies

The identification of the precise mutations associated with

many forms of hereditary anaemias will allow routine

characterisation by nucleic acid sequence analysis, facilitating

the use of disease specific diagnostic tests based on polymerase

chain reaction. This will provide more precise prognostic

information for affected individuals as well as accurate

identification of affected embryos. As reliable prenatal

diagnosis at an early stage will be available, so will an increasing

range of prenatal treatment options.

For patients affected by hereditary anaemias such as sickle

cell disease and thalassaemia, advances in transplantation

immunology are likely to permit transplantation across tissue

barriers with reduced immunosuppression, making bone marrow

transplantation a treatment option for all affected patients. In

addition, gene therapy for these disorders could provide another

potentially curative strategy, although the genetic correction of

Figure 15.4 Gene therapy may provide a curative strategy for a variety of

hereditary anaemias still presents complex challenges. In sickle

disorders, including haemoglobinopathies, coagulation disorders, and

cell disease, for example, delivery of normal copies of the

other single gene disorders

ABC of Clinical Haematology

globin gene to haemopoietic stem cells will be insufficient for

Box 15.2 Clinical trials of gene therapy in haemophilia

cure. As continued Hb S production would be damaging, the

A number of phase I clinical trials of gene therapy for

mutated globin genes must also be removed. Stem cell surgery

haemophilia A and B are ongoing or completed. They

techniques might be used to achieve such an aim.

illustrate well the different gene delivery systems under

investigation—the safest and most effective method of gene

delivery remains to be determined

• Transkaryotic Therapy Inc.

Six subjects received omental implantation of autologous

fibroblasts modified ex vivo by transfection of DNA

encoding B-domain deleted human FVIII

• Chiron

A replication defective Moloney murine leukaemia virus

vector delivering B-domain deleted human FVIII is being

used

• Avigen

Figure 15.5 Haemophilic patient with inhibitors and severe spontaneous

Subjects with haemophilia B receive intramuscular injection

bleeding. Currently the development of inhibitors represents one of the

of adeno-associated virus vector encoding human FIX

biggest problems facing patients with haemophilia

• Genstar

This study is the first human trial to employ a “gutless”

adenoviral vector. The vector will deliver full length human

FVIII cDNA under the control of the highly liver-specific

Haemophilia

albumin promoter which should result in targeting of FVIII

expression to the liver

As specific mutations have now been identified to account

for a large proportion of patients with haemophilia, routine

characterisation of all haemophilias by direct sequence analysis

is likely. This will facilitate accurate carrier diagnosis and thus

the use of disease specific diagnostic tests based on polymerase

chain reaction for accurate identification of affected embryos.

As for the inherited anaemias, several prenatal treatments are

likely to become available.

Dependence on blood products with the attendant risk of

(a)

viral transmission has been disastrous for many patients with

haemophilia, but this is unlikely to be a problem in the future.

ATP

ADP

Recombinant human factor VIII is already available,

recombinant coagulation factor VIIa is improving the prospects

for haemophilic patients with inhibitors to factor VIII, and the

development of other recombinant coagulation factors will

PO4

Bcr-Abl protein

ultimately obviate the need to use fractionated human blood.

Definitive gene therapy of haemophilia also has excellent

Phosphorylated substrate

prospects. Haemophilia is known to be curable by liver

transplantation, indicating that it should also be curable by

genetic modification of host cells to produce normal factor

VIII. Regulation of gene expression is not thought to be a

Proliferation of

critical issue as a moderate excess of factor VIII has no known

abnormal cells

procoagulant effect. Theoretically, production of only a small

amount, perhaps 5%, of the required coagulation protein

(b)

should be enough to convert clinically severe into clinically

mild haemophilia. There are concerns that cells producing

factor VIII might be recognised as “foreign” by the patient and

Tyrosine kinase

inhibitor blocks

rejected. The first clinical study of gene therapy for

ATP binding

haemophilia A to be published, in which fibroblasts engineered

to produce FVIII were implanted intraperitoneally, did not set

out to provide an answer to this question.

There are also concerns relating to the generation of

Bcr-Abl protein

coagulation factor inhibitors, thus recruitment of patients to

Substrate cannot

the early studies should proceed with great caution. A number

be phosphorylated

of clinical studies of gene therapy in both haemophilia A and B

are now ongoing, employing retrovirus, adenovirus and

adeno-associated virus vectors.

Proliferation of

abnormal cells cannot occur

Haematological malignancy

Figure 15.6 (a) Aberrant protein Bcr-Abl is produced in CML cells as a

result of translocation of material from chromosome 9 to chromosome 22.

An understanding of the molecular mechanism of malignant

It binds ATP then transfers phosphate groups to tyrosine residues on

various substrate proteins. Downstream events lead to proliferation of the

transformation in malignant disorders forms the basis for

CML cells. (b) When STI571 binds to the ATP binding site of Bcr-Abl, the

improved diagnostic sensitivity and the monitoring of minimal

tyrosine kinase activity of this protein is inhibited and the events leading to

residual disease and paves the way for more directed treatment

proliferation of the CML cells cannot occur

The future of haematology: the impact of molecular biology and gene therapy

Box 15.3 Success of anti-CD20 antibody therapy in

Table 15.2 Scientific techniques and approaches that have

lymphoma

made major contributions to modern haematology

Humanised antibody

Technique

Applications in haematology

•

No anti-antibody immune reactions—permits multiple

administrations

Gene cloning and sequencing

Elucidation of the molecular

Multiple potential effector mechanisms

allow identification,

pathology of disease and

•

Fixes complement

characterisation, and

diagnostic tests based on

• Elicits ADCC reaction

manipulation of genes

the polymerase chain reaction

•

Binds to Fc receptors on effector cells

responsible for specific

CD20 target restricted to B cells

products or diseases

•

Transient depletion of normal B cells seen during therapy

Polymerase chain reaction is a

Rapid diagnosis of infectious

has minimal clinical consequences

highly sensitive and versatile

diseases in immunocompromised

Well tolerated

technique for amplifying

patients (for example,

•

Adverse reactions are mostly related to the infusion of the

very small quantities of

hepatitis C); minimal residual

drug. Late adverse reactions are uncommon and have been

DNA. Amplification of RNA

disease detection in

mostly immune phenomena

molecules is possible after

haematological malignancies

initial reverse transcription of

where the molecular defect is

RNA into DNA (RT-PCR)

known; carrier detection and

antenatal diagnosis in

Box 15.4 The future of antibody therapy for

haemophilias and hereditary

lymphoma?

anaemias

Monoclonal antibodies allow

Increased diagnostic precision,

Radioimmunotherapy

immunohistochemistry of

“positive purging,” ex vivo gene

•

The use of monoclonal antibodies to deliver radioisotopes

tissue and cells, analysis and

delivery, and ex vivo expansion of

to the target cells holds great promise and is poised to join

cell sorting with fluorescence

progenitor cells are possible as

“mainstream” therapies for lymphoma

activated cell sorter (FACS),

a result of the fact that

Antibody delivery of immunotoxins

and cell purification

populations of haemopoietic cells

•

Target antigens which are internalised are needed for this

containing a high proportion of

approach

primitive progenitors can be

Targeted delivery of oncolytic viruses via viral display of single

isolated

chain antibodies

Mammalian tissue culture and

Allows gene therapy, tissue

•

In vitro studies and work in animal models suggest this may

gene transfer to mammalian

engineering, and study of

be a feasible approach

cells provide methods for

gene expression and function

Novel target antigens

studying gene expression.

•

Target antigens other than CD20 for which this approach is

Reporter genes can be used

being developed clinically include CD22, HLA-DR, and CD52

to study gene expression in

cell lines in vitro. Transgenic

animals can be created by

inserting intact or manipulated

interventions, including the eventual possibility of targeting the

genes into the germ line of an

causative genetic defects. The new genetic information

animal providing an in vivo

available from genomic studies may eventually lead to new,

model of gene function

genetic classifications of malignancies.

Protein engineering and

Recombinant drugs (for

New pharmaceuticals based on our new understandings are

construction of recombinant

example, the haemopoietic

already being developed the knowledge that deregulation of

proteins allow production of

growth factors), antibody

the tyrosine kinase activity of the Bcr-Abl fusion protein

large quantities of

engineering to produce

human proteins. Proteins with

therapeutic antibodies,

is the mechanism for oncogenesis in CML has led to the

modified or novel functions

recombinant blood products

development of a new drug therapy, STI 571. This Abl-specific

can be rationally designed

free from risk of viral

tyrosine kinase inhibitor has now demonstrated the potential of

and produced

contamination

molecularly targeted therapies, and it is likely that the number

of novel compounds will increase. The remarkable therapeutic

success of monoclonal antibodies against the CD20 antigen in

the treatment of lymphoma also paves the way for further

therapeutic success with antibody therapies. More new

biological agents will be developed that exploit the underlying

mechanism of malignancy. A good example of this is the

therapeutic use of replicative agents, such as oncolytic viruses,

whose cytolytic capability is conditional upon some feature

confined to malignant cells.

An increasing understanding of the role of the immune

system in the elimination of haematological malignancies

should also lead to more subtle approaches to therapy. It is clear

that although current chemotherapy regimens do not eliminate

all malignant cells, some patients can be cured after such

conventional therapy and that a graft versus malignancy effect

exists for most haematological malignancies. Strategies aimed at

enhancing the immune response to malignant cells such as, for

example, idiotypic vaccination in lymphoma, are likely to play

an important role, particularly in the setting of minimal residual

disease. An understanding that novel therapies must be

ABC of Clinical Haematology

developed in the context of existing treatment and that the

effective therapies applied to a increasing number of patients

right time to apply such therapies may not always be in the

of advancing age and co-morbidity due to significant reductions

terminal stages of malignant disease is emerging.

in toxicity. Transplantation across HLA barriers has been

Enhancement of the safety of existing effective treatments

demonstrated in a number of animal models. The use of non-

and increasing the number of people to whom they are

myeloablative conditioning regimens should significantly

applicable will remain an important aspect of progress in the

reduce the toxicity of therapies which are known to be effective

treatment of haematological malignancy. We are likely to see

“Pharmacogenomics” may offer us the opportunity to identify

the genetic mechanisms that affect the response to individual

chemotherapy drugs in any given patient, so that those drugs

or combinations of drugs offering the best therapeutic index

Box 15.5 Glossary

for a particular person and their tumour can be used.

General molecular biology

• Recombinant DNA—Any DNA sequence that does not

occur naturally but is formed by joining DNA segments

Further reading

from different sources

• Emilien G, Ponchon M, Caldas C, Isaacson O, Maloteaux JM.

• Polymerase chain reaction—Process by which genes or gene

Impact of genomics on drug discovery and clinical medicine.

segments can be rapidly, conveniently, and accurately

QJM 2000;93(7):391-423.

copied, producing up to 10¹² copies of the original

• Ilidge TM, Bayne MC. Antibody therapy of lymphoma. Expert

sequence in a few hours

Opin Pharmacother 2001;2(6):953-61.

• Reverse transcription—Process by which RNA is used as a

• Mannucci PM, Tuddenham EG. The hemophilias—from royal

template for the production of a DNA copy

genes to gene therapy. N Engl J Med 2001;344(23):1773-9.

• Transcription factor—Protein that is able to bind to

• Mauro MJ, O’Dwyer M, Heinrich MC, Druker BJ. STI571: a

chromosomal DNA close to a gene and thereby regulates

paradigm of new agents for cancer therapeutics. J Clin Oncol

the expression of the gene

2002;20(1):325-34.

Haematology and immunology

• Miller DG, Stamatoyannopoulos G. Gene therapy for

• Stem cell—Pluripotent cell that has the ability to renew

hemophilia. N Engl J Med 2001;344(23):1782-4.

itself or differentiate. The haemopoietic stem cell gives rise

• Roth DA, Tawa NE Jr, O’Brien JM, Treco DA, Selden RF.

to all lineages of haemopoietic cells

Nonviral transfer of the gene encoding coagulation factor VIII in

• Minimal residual disease—Cancer that is still present in the

patients with severe hemophilia A. N Engl J Med

body after treatment but remains undetectable by

2001;344(23):1735-42.

conventional means—for example, light microscopy

• Shipp MA, Ross KN, Tamayo P et al. Diffuse large B-cell

• Immunophenotype—The cell surface markers on any given

lymphoma outcome prediction by gene-expression profiling and

cell detected by the use of monoclonal antibodies

supervised machine learning. Nat Med 2002;8(1):68-74.

• Genomics—The systematic study of the human genome

• Proteomics—The systematic study of the human proteome

• Apoptosis—Programmed cell death

Figure 15.3 is reproduced from Aitman (BMJ 2001;323:611-15)

• Adoptive immunotherapy—The transfer of immune cells for

and is adapted from Golub TR, Slonim DK, Tamayo P, Huard C,

therapeutic benefit

Gaasenbeek M, Mesirov JP, et al. Molecular classification of

• Transgenic animals—Animals with an intact or manipulated

cancer: class discovery and class prediction by gene expression

gene inserted into their germline

monitoring (Science 1999;286:531-7).

Index

page numbers in italics refer to tables and boxed text, those in bold refer to figures

aciclovir 55, 64

bleeding disorders 43-5

activated protein C resistance (APCR) 45

acquired 44-5

acute lymphoblastic leukaemia 22, 23, 24

congenital 44

prognosis 26

inherited 43

acute myeloid leukaemia 23, 24

laboratory investigations 43-4

prognosis 26

bleomycin 50

acute promyelocytic leukaemia 63

blood

Addison’s disease of the adrenal gland 5

stem cell transplantation 52-6

adenovirus vectors 68

viscosity

adult haemoglobin see Hb A; Hb A₂

blood transfusion 3-4

adult T cell leukaemia 26

exchange in infants 58

AIDS-related non-Hodgkin’s lymphoma

49-50

idiopathic myelofibrosis 17

alcohol consumption 6

intrauterine 57

amyloid deposition 39

intravascular into umbilical artery

amyloidosis 41-2

sickle cell crisis

10, 62

anabolic steroids 15

bone marrow

anaemia

aspirate 2

chronic disease in elderly people 60

donation registries 52-3

hereditary 9-13

failure 29, 33

mutation identification 67

fibrosis

16, 17

transplantation immunology 67-8

harvesting 53-4

infection in infants 57

idiopathic myelofibrosis 16-17

neonates 57

macrocytosis 7

normochromic normocytic 39

precursor cell apoptosis 33

prematurity 57

stem cell transplantation 52-6