failure (see p562). Oster, W. et al. (1990) Erythropoietin for the treatment of anemia of malignancy associated with neoplastic bone marrow infiltration. J Clin Oncol, 8, 956 \200\223962. 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 121 Red cell disorders 121 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 122 Aplastic anemia Definition A gross reduction or absence of haemopoietic precursors in all 3 cell lin- eages in bone marrow resulting in pancytopenia in peripheral blood. Although this encompasses al l situations in which there is myelosuppres- sion, the term is generally used to describe t hose in which spontaneous marrow recovery is unusual. 122 Incidence Rare 5 cases per million population annually. Wide age range, slight increase ar ound age 25 years and >65 years. 10 more common in Orientals. Causes Divided into categories where aplasia is regarded as: 2 Inevitable \200\223 TBI dose of >1.5Gy (note: >8Gy always fatal in absence of graft rescue). \200\223 Chemotherapy e.g. high dose busulfan. 2 Hereditary \200\223 Fanconi syndrome \200\224stem cell repair defect resulting in abnormali- ties of skin, facies, musculo-skeletal system and urogenital systems. \200\223 BM failure often delayed until adulthood. 2 Idiosyncratic \200\223 Chronic benzene exposure. \200\223 Drug-induced, but not dose related \200\224ma inly gold, chloramphenicol, phenylbutazone, NSAIDs, carbamazepine, phenytoin, mesalazine. \200\223 Genetic predisposition demonstrated for chloramphenicol. 2 Post-viral \200\223 Parvoviral infections \200\224classically red cell aplasia but may be all ele- me nts. Devastating in conjunction with chronic haemolytic anemia e.g. aplastic sickle crisis. \200\223 Hepatitis viruses A, B and C, CMV and EBV. 2 Idiopathic \200\223 Constitute the majority of cases. Classification 2 According to severity most clinically useful. 2 Defines highest risk group s. Classification of severity in aplastic anemia neutrophils <0.5 109/L <20 109/L platelets reticulocytes <1% neutrophils <0.2 109/ L, and infection present Severe 2 of the following: Very severe 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 123 Red cell disorders Clinical features Reflects the pancytopenia. Bleeding from mucosal sites common, with purpu ra, ecchymoses. Infections, particularly upper and lower respiratory tracts, skin, mouth, p eri-anal. Bacterial and fungal infections common. Anemic symptoms usually less severe due t o chronic onset. 123 Diagnosis and investigation 2 FBC and blood movie show pancytopenia, MCV may be 4, movie mo r- phology unremarkable. 2 Reticulocytes usually absent. 2 BM aspirate and trephine show gross reduction in all haemopoietic tissue replaced by fat spaces \200\224important to exclude hypocellular MDS or leukemia \200\224the main differential diagnoses. 2 Flow cytometry using anti-CD55 and anti-CD59 will show lack of both membrane proteins. Ham \200\231s acid lysis test is now largely obsolete. 2 Specialized cyt ogenetics on blood to exclude Fanconi syndrome (see p456). Complications 2 Progression to more severe disease. 2 Evolution to PNH \200\224occurs in 7 %. 2 Transformation to acute leukemia occurs in 5 \200\22310%. Treatment 2 Mild cases need careful observation only. More severe will need sup- portive treatment with red cell and platelet transfusions and antibiotics as needed. Blood products should be CMV \200\223ve, and preferably leu- codepleted to reduce risk of sensit isation. 2 Specific treatment options are between allogeneic transplant and immunosuppression. 2 Sibling allogeneic transplant treatment of choice for those <50 with sibling donor. Shoul d go straight to transplant avoiding immunosup- pression and blood products if possible. 2 Matched unrelated donor transplant should be considered in <25 age group. 2 Immunosuppressive options include anti-lymphocyte globulin (ALG) cyclosporin. Response to ALG may take 3 months. Refractory or relapsing patients may respond to a second course of ALG from another animal. 2 Cyclosporin post-ALG looks promising. 2 Androgens or danazol may be useful in some cases. Abkowitz, J.L. (2001) Aplastic anemia: which treatment? Ann Intern Med, 135, 524 \200\22352 6; Young, N.S. & Barrett, A.J. (1995) The treatment of severe acquired aplastic anemia. Blo od, 85, 3367 \200\2233377. 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 124 Paroxysmal nocturnal haemoglobinuria Definition Acquired clonal abnormality of cell membranes rendering them more sen- sitive to complement-mediated lysis, most noticeable in RBCs. Cells lack phosphatidylinositol glycop roteins (PIG) transmembrane anchors. 124 Incidence Rare. Aplastic anemia is closely related. Clinical features 2 Chronic intravascular haemolytic anemia particularly overnight (?due to lower blood pH). Infections trigger acceleration of haemolysis. 2 WBC and platelet production also often 5. 2 Chronic haemolysis may induce nephropathy. 2 Haemoglobinuria usually results in iron deficiency. 2 44 tendency to venous thrombosis part icularly at atypical sites e.g. hepatic vein (Budd \200\223Chiari syndrome), sagittal sinus thrombosis. 2 Fatigue, dysphagia and impotence occasionally seen. Diagnosis and treatment 2 FBC, blood movie \200\224polychromasia and reticulocytosis (cf. AA). 2 BM aspirate and trephine biopsy \200\224usually hypoplastic with increased fat spac e but with erythropoietic nests or islands distinct from AA. 2 Ham \200\231s test (acidifie d serum lysis) is invariably +ve though seldom used now. 2 Cellular immunophenotype shows altered PIG proteins, CD55 and CD59. 2 Urinary haemosiderin +ve. Complications 2 May progress to more severe aplasia. 2 Transforms to acute leukemia in 5%. 2 Serious thromboses in up to 20%. Treatment: 2 Chronic disease \200\224supportive care may be satisfactory in mild cases. 2 Iron replacement usually required. 2 Trial of steroid/androgens/danazol may 5 symptoms and transfusion need. 2 ALG/cyclosporin may be indicated for more severe cases as for aplastic anemia. 2 Acute major thromboses should be treated aggressively with urgent thrombolysis and 10 day s heparin. Long-term warfarin mandatory. Consider warfarin prophylaxis after any one clotti ng episode. 2 Severe cases <50 years should be considered for sibling allogeneic transplant if they have a donor \200\224consider MUD in <25 age group if no sibling donor. 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 125 Red cell disorders Prognosis: Median survival from diagnosis is 9 years. Major cause of mortality is thrombosi s and marrow failure. Molecular genetic basis now established \200\224could be a candidate disease for gene transplantation. 125 Hillmen, P. et al. (1995) Natural history of paroxysmal nocturnal hemoglobinuria. N Engl J Med, 333, 1253 \200\2231258; Rosse, W.F. (1997) Paroxysmal nocturnal hemoglobinuria as a mo lecular disease. Medicine (Baltimore), 76, 63 \200\22393. 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 126 Pure red cell aplasia Definition A severe anemia characterized by reticulocytes <1% in PB, <0.5% mature erythrobl asts in BM but with normal WBC and platelets. 126 Incidence Rare. Classification of red cell aplasia Congenital Diamond \200\223Blackfan anemia (DBA), see p452 Acquired Childhood: Transient erythroblastopenia of childhood (TEC) Adults: Primary: autoimmune or idiopathic Secondary chronic: thymoma, hematological malignancies es pecially CLL, pernicious anemia, some solid tumors, SLE, RA, malnutrition with riboflavin d eficiency Secondary transient: infections especially Parvovirus B19, CMV, HIV, many drugs R ecent interest following red cell aplasia in renal patients treated with subcutaneous Epo Clinical features 2 Lethargy usually only symptom of the anemia since slow onset. 2 No abno rmal physical signs except of any underlying disease. Diagnosis and investigations 2 FBC shows severe normochromic, normocytic anemia with retics <1%. WBC and platelets normal. 2 BM shows absence of erythroblasts but is normocellular (distinguishes from aplastic anemia). Treatment 2 Treat underlying cause first if identified. 2 Remove thymoma. 2 If due to parvo virus B19, try IVIg. 2 Assume immune origin if no other cause found and give prednisolone 6 0mg od PO as starter dose 40% response. Failure of response, try cyclosporin or ALG or aza thioprine. Prognosis 2 15% have spontaneous remission. 65% will respond to immunosup- pression. 2 50% will relapse but 80% of relapsers will respond again. 2 A few progress to AA or AML. 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 127 Red cell disorders 127 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 128 Iron overload Iron is an essential metal but overload occurs when intake of iron exceeds requirements and occurs due to the absence in humans of a physiological mechanism to excrete excess iron. S ustained 4 Fe intake (dietary or par- enteral) may result in iron accumulation, overload an d potentially fatal tissue damage. 128 Timing and pattern of tissue damage is determined by rate of accumula- tion, the quantity o f total body iron and distribution of iron between retic- uloendothelial (RE) storage sites and vulnerable parenchymal tissue. Iron accumulation in parenchymal cells of the liver, he art, pancreas and other organs is the major determinant of clinical sequelae. Haemochromatosis 2 Inherited (autosomal recessive) occurring in up to 0.5% population (N. Europe). 2 Haemochromatosis locus is tightly linked to the HLA locus on chro- mosome 6p and up to 10% population are heterozygous. 2 Single missense mutation found in the homozygous state in 80% of patients. 2 The gene designated HFE is an MHC class Ib gene. 2 Homozygotes develop symptomatic iron o verload. Caused by failure to regulate iron absorption from bowel causing progres- sive increase in total body iron. Parenchymal accumulation occurs initially in liver then pancreas, heart, s kin and other organs rather than RE sites. Symptoms do not usually develop until middle age when body iron stores of \211 15 \200\22320g have accumulated. Environmental factors (e.g . alcohol use in males and menstruation in females) affect rate of accumulation and age at presentation. Clinical expression of haemochromatosis is seen 10 more commonly in 9. Only 25% of heterozygotes show evidence of minor increases in iron stores and clinical problems do not occur. Clinical manifestations of iron overload only occur in homozygotes and presentation as \200\230bronze diabetes \200\231 is characteristic. Clinical features of Fe overload (homozygous haemochromatosis) 2 Skin pigmentation 2 Hepatic dysfunction Slate gray or bronze discolouration Hepatomegaly, chronic hepatitis, fibrosis, cirrhosis, h epatocellular carcinoma (20 \200\22330%) Retinopathy, nephropathy, neuropathy, vascular com plications Hypogonadism, impotence 2 Diabetes mellitus 2 Gonadal dysfunction 2 Other endocrine dysfunction Hypothyroidism, hypoparathyroidism, adr enal insufficiency Unknown etiology (25%) Cardiomyopathy, heart failure, dysrhythmias (10 \200\22315%) Arthropathy 2 Abdominal pain 2 Cardiac dysfunction 2 Chondrocalcinosis 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 129 Red cell disorders Evaluation of iron status Most useful indirect measure of iron stores is serum ferritin est imation. Rises to maximum concentration of 4000 g/L and may underestimate extent of iron o verload in some patients. Note: may be spuriously increased by infection, inflammation or n eoplasia. The % transferrin satu- ration provides confirmatory evidence but no measure of t he extent of iron overload. Liver biopsy provides a direct albeit invasive measure of iron stores (% iron concentration by weight) and visual assessment of iron distribution, and the extent of tissue damage. 129 Diagnosis May be difficult to differentiate haemochromatosis from iron overload 2 to othe r causes, particularly that associated with chronic liver disease. Recent identification of HFE gene will provide a tool for more definitive diagnosis and screening of relatives (pre viously performed by serum fer- ritin estimation). Management 2 Aim to reduce iron stores to <50 g/L and prevent complications of overload. 2 Achieved by regular venesection (500mL blood) on weekly basis until iron deficiency develops (may take many months). 2 Hb should be measured prior to each venesection and response to therapy can be monitored by intermittent measurement of the serum ferritin. 2 Once iron deficiency develops a maintenance regimen can be com- menced with venesection every 3 \200\2234 months. Natural history Cirrhosis and hepatocellular carcinoma are the most common causes of death in patients with haemochromatosis and are due to hepatic iron accumulation. Cirrhosis does not usually develop until the hepatic iron concentration reaches 4000 \200\2235000 g/g of liver (normal 50 \200\223500 g/g). Hepatocellular carcinoma is the cause of death in 20 \200\22330% but does not occur in the absence of cirrhosis which increases the risk over 20 0 . If venesection can be commenced prior to the development of cirrhosis and other compli cations of haemosiderosis the life expectancy is that of a normal individual. Reduction of iron overload by venesection has only a small effect on symptomatology which has already de veloped: skin pig- mentation diminishes, liver function may improve, cardiac abnormalities may resolve, diabetes and other endocrine abnormalities may improve slightly, arthropathy i s unaffected. Olynyk, J.K. et al. (1999) A population-based study of the clinical expression of the hemoc hro- matosis gene. N Engl J Med, 341, 718 \200\223724; Sanchez, A.M. et al. (2001) Prevalen ce, donation prac- tices, and risk assessment of blood donors with hemochromatosis. JAMA, 2 86, 1475 \200\2231481. 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 130 Transfusion haemosiderosis Iron overload occurs in patients with transfusion dependent anemia, notably thalassaemia ma jor, Diamond \200\223Blackfan syndrome, aplastic anemia and acquired refractory anemia. In many of these conditions iron overload is aggravated by physiological mechanisms which prom ote increased dietary absorption of iron in response to ineffective erythro- poiesis. Each unit of blood contains 250mg iron and average transfusion dependent adult receives 6 \200 \22310g of iron/year. Distribution of iron is similar to haemochromatosis with primarily li ver parenchymal cell accumulation followed by pancreas, heart and other organs. Cardiac dep osition occurs in patients who have received 100 units of blood (20g iron) without chela- t ion, and is followed by damage to the liver, pancreas and endocrine glands. 130 Clinical features of iron overload in children who require transfusion support for heredita ry anemia are listed. Similar problems excluding those related to growth and sexual maturat ion develop in patients who commence a transfusion program for acquired refractory anemia i n later life. Features of transfusion haemosiderosis in hereditary anemia 2 Growth retardation in second decade. 2 Hypogonadism \200\224delayed or absent sexual maturation. 2 Skin pigmentation \200\224slate gray or bronze discolouration. 2 Hepatic dysfunction \200\224hepatomegaly, c hronic hepatitis, fibrosis, cir- rhosis, hepatocellular carcinoma. 2 Diabetes mellitus. 2 Other endocrine dysfunction \200\224rarely hypothyroidism, hypopara thy- roidism, adrenal insufficiency. 2 Cardiac dysfunction \200\224cardiomyopathy, heart failure, dysrhythmias (main cause of death). 2 Death from heart disease in adolescence. Management 2 Iron chelation therapy by parenteral desferrioxamine is the only treat- ment for patients with transfusion haemosiderosis, who remain anemic. Haemosiderosis due to previous transfusions in conditions where Hb now normal e.g. treated AML, may be venesecte d to remove iron. 2 Regular treatment is required in transfusion dependent children if they are to avoid the consequences of iron overload in the second decade of life. 2 SC administration of desferrioxamine by portable syringe pump over 9 \200\22312h on 5 \200\2237 nights/week is a common regimen. 2 Ascorbic acid supplementation may help mobilize iron and increase excretion with desferrioxamine but can cause hazardous redistribution of storage iron. 2 Early and regular desferrioxamine infusion 5 hepatic iron and improves hepatic function, promotes growth and sexual development and pro- tects against heart disease and early death . 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 131 Red cell disorders 2 Much work has been expended in the search for an effective non-toxic oral chelator and de feriprone is currently under evaluation in clinical trials. 131 Natural history The prognosis of the underlying hematological condition in transfusion depe ndent elderly patients may eliminate the need for iron chelation. In others with a longer l ife expectancy, IV infusion of desferrioxamine with each blood transfusion may adequately d elay the rate of iron accumula- tion. Other causes of haemosiderosis Dietary iron overload may also occur as a result of chronic over-ingestion of iron-containing traditional home-brewed fermented maize beverages peculia r to sub-Saharan Africa, which overwhelms physiological controls on iron absorption. Iron s tores may >50g and iron is initially deposited in both hepatocytes and Kupffer cells but wh en cirrhosis develops, accumu- lates in the pancreas, heart and other organs. Over-ingestio n of medicinal iron may possibly have a similar though less dramatic effect but is certainl y harmful to patients with iron-loading disorders. The excessive iron absorption seen in pa tients with chronic liver disease is associated with accumulation in Kupffer cells rather t han hepatic parenchyma. Rare con- genital defects associated with iron overload have been r eported. 02-red cell disorders.qxd 10.12.2003 04.11 PM Page 132 This page intentionally left blank 132 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 133 White blood cell abnormalities 3 Neutrophilia 134 Neutropenia 136 Lymphocytosis and lymphopeni a 138 Eosinophilia 140 Basophilia and basopenia 142 Monocytosis and monocytopenia 144 Mononucleosis syndromes 146 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 134 Neutrophilia Neutrophils are derived from same precursor as monocytes. Cytoplasm contains granules; the nucleus has 3 \200\2234 segments. Functions include chemotaxis \200\224neutrophils migrate to sites of inflammation by chemotactic factors e.g. complement components (C5a and C3), a nd cytokines. Cytotoxic activity is via phagocytosis and destruction of particles/invading microorganisms (latter often antibody coated = opsonised). Granules contain cationic protei ns7lyse Gram \200\223ve bacteria, \200\230defensins \200\231, myeloper- oxidase \200\224 interacts with H2O2 and HCl7hypochlorous acid (HOCl); \200\223) and hydroxyl lysozyme (hyd rolyses bacterial cell walls); superoxide (O2 (OH \200\223) radicals. Neutrophil lifespan i s 1 \200\2232d in tissues. 134 Normal neutrophil count 2.0 \200\2237.5 109/L (neonate differs from adult; see Normal ra nges p690). Neutrophilia is defined as an absolute neutrophil count >7.5 109/L. Mechanisms 2 Increased production. 2 Accelerated/early release from marrow7blood. 2 Demargi nation (marginal pool7circulating pool). Causes 2 Infection (bacterial, viral, fungal, spirochaetal, rickettsial). 2 Inflammation (t rauma, infarction, vasculitis, rheumatoid disease, burns). 2 Chemicals e.g. drugs, hormones , toxins, haemopoietic growth factors e.g. G-CSF, GM-CSF, adrenaline, corticosteroids, venoms. 2 Physical agents e.g. cold, heat, burns, labor, surgery, anesthesia. 2 Hematological e.g. myeloproliferative disease, CML, PPP (primary proliferative polycythaemia), myelofibrosis, chronic neutrophilic leukemia. 2 Other malignancies. 2 Cigarette smoking. 2 Post-splenectomy. 2 Chronic bleeding. 2 Idiopa thic. Investigation History and examination. Ask about cigarette smoking, symptoms suggesting occ ult malignancy. Other investigations ESR, CRP. Treatment Usually treatment of underlying disorder is all that is required. Leukaemoid reaction May resemble leukemia (hence name); see 4 WBC (myeloblasts and promyelo cytes prominent). Occurs in severe and/or chronic infection, metastatic malignancy. 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 135 White blood cell abnormalities 135 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 136 Neutropenia Defined as absolute peripheral blood neutrophil count of <2.0 109/L. Racial variation: B lack and Middle Eastern people may have neutrophil count of <1.5 109/L normally. Congenital neutropenia syndromes Kostmann \200\231s syndrome: (cid:9) Pediatric hematology, p459. 136 Chediak \200\223Higashi: (cid:9) Pediatric hematology, p465. Shwachman \200\223Diamond syndrome: (cid:9) Pediatric hematology, p459. Cyclical neutropenia: 3 \200\2234 week periodicity; often 21d cycle, lasts 3 \200\2236d. Miscellaneous: dyskeratosis congenita. transcobalamin II deficiency, reticular dysgenesis, Acquired neutropenia Acquired neutropenia: commonest causes Infection Viral, e.g. influenza, HIV, hepatitis, overwhelming bacterial sepsis Drugs Anticonvulsants (e.g. phenytoin) Antithyroid (e.g. carbimazole) Phenothiazines (e.g. chlorp romazine) Antiinflammatory agents (e.g. phenylbutazone) Antibacterial agents (e.g. cotrimox azole) Others (gold, penicillamine, tolbutamide, mianserin, imipramine, cytotoxics) Immune mediated Autoimmune (antineutrophil antibodies) SLE Felty \200\231s syndrome (rheumatoid arthritis + neutropenia + splenomegaly; no correlation between spleen size and degree of neutropenia) As part of pancytopenia Bone marrow failure Leukemia, lymphoma, LGLL, haematinic deficiency, anorexia Splenomegaly Any cause Clinical features \200\224when severe neutropenia: throat/mouth infection, oral ulceration, septicaemia. Diagnosis \200\224examine peripheral blood check haematinics, autoimmune profile, anti-neut rophil antibodies, haematinics, bone marrow aspirate and trephine biopsy if indicated (e.g. severe or prolonged movie, 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 137 White blood cell abnormalities neutropenia, or features suggestive of infiltration of marrow failure syndrome). Treatment \200\224consists of prompt antibiotic therapy if infection, IVIg and corticostero ids may be helpful but effects unpredictable. In seriously ill patients consider use of G-C SF (need to exclude underlying leukemia before starting therapy with growth factors). Consi der prophylaxis with low dose antibiotics (e.g. ciprofloxacin 250mg bd) and antifungal (e.g . fluconazole 100mg od) agents. Drug-induced neutropenia usually recovers on stopping suspe cted agent (may take 1 \200\2232 weeks). 137 Bux, J. et al. (1998) Diagnosis and clinical course of autoimmune neutropenia in infancy: a nalysis of 240 cases. Blood, 91, 181 \200\223186; Dale, D.C., Bolyard, A.A. & Aprikyan, A. (2002) Cyclic neu- tropenia. Semin Hematol, 39, 89 \200\22394. 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 138 Lymphocytosis and lymphopenia Lymphocytes are small cells with a high N:C ratio; some (e.g. natural killer cells) have pr ominent cytoplasmic granules. Two principal types: B and T lymphocyte. B-cells express mono clonal surface (not cytoplasmic) IgM and often IgD. B-cell stimulation through cross linkag e of surface Ig molecules or via effector T cells causes their differentiation into plasma cells. Predominant role is humoral immunity via Ig secretion. 138 T cells are derived from stem cells that undergo maturation in thymus and express T-cell re ceptor molecule (CD3) on cell surface. Responsible for cell-mediated immunity e.g. delayed hypersensitivity, graft rejection, contact allergy and cytotoxic reactions against other ce lls. Lymphocytosis (peripheral blood lymphocytes >4.5 109/L) 2 Leukaemias and lymphomas inclu ding: CLL, NHL, Hodgkin \200\231s disease, acute lymphoblastic leukemia, hairy cell leukemi a, Waldenstr m \200\231s macroglobulinaemia, heavy chain disease, mycosis fungoides, S za ry syndrome, large granular lymphocyte leukemia, adult T-cell leukemia lymphoma (ATLL). 2 Infections e.g. EBV, CMV, Toxoplasma gondii, rickettsial infection, Bordetella pertussis, mumps, varicella, coxsackievirus, rubella, hepatitis virus, adenoviru s. 2 \200\230Stress \200\231 e.g. myocardial infarction, sickle crisis. 2 Trauma. 2 Rheumatoi d disease (occasionally). 2 Adrenaline. 2 Vigorous exercise. 2 Post-splenectomy. 2 b thalas saemia intermedia. Lymphopenia (peripheral blood lymphocytes <1.5 109/L) 2 Malignant disease e.g. Hodgkin \200\231s disease, some NHL, non-haematopoi- etic cancers, angioimmunoblastic lymphadenopathy. 2 MDS. 2 Collagen vascular disease e.g. rheumatoid, SLE, GvHD. 2 Infections e.g. HIV. 2 Che motherapy. 2 Surgery. 2 Burns. 2 Liver failure. 2 Renal failure (acute and chronic). 2 Anor exia nervosa. 2 Iron deficiency (uncommon). 2 Aplastic anemia. 2 Cushing \200\231s disease. 2 Sarcoidosis. 2 Congenital disorders (rare) such as SCID, reticular dysgenesis, agammaglobulinaemia (Swiss type), thymic aplasia (DiGeorge \200\231s syn- drome), ataxia te langiectasia. 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 139 White blood cell abnormalities 139 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 140 Eosinophilia Differential diagnosis Common 2 Drugs (huge list e.g. gold, sulphonamides, penicillin); erythema multi- forme (Stevens \200\223Johnson syndrome). 2 Parasitic infections: hookworm, Ascaris, tapeworms, filariasis, amoebi- asis, schistosomiasis. 140 2 Allergic syndromes \200\224asthma, eczema, urticaria. Less common 2 Pemphigus. 2 Dermatitis herpetiformis (DH). 2 Polyarteritis nodosa (PAN). 2 S arcoid. 2 Tumors esp. Hodgkin \200\231s. 2 Irradiation. Rare 2 Hypereosinophilic (Loeffler \200\231s) syndrome. 2 Eosinophilic leukemia. 2 AML with eosinophilia esp. M4Eo (see p151). Discriminating clinical features 2 Drugs: history of exposure, time course of eosinophilia with resolution on cessation of drug. 2 Allergic conditions: history of eczema, urticaria or typical rashes. Symptoms and signs of asthma. 2 Parasites: history of exposure from foreign travel, symptoms and signs of iron deficiency anemia (hookworm is commonest cause world- wide). Blood movie may show filariasis. Stool m icroscopy and culture for ova, cysts and parasites for amoebiasis, Ascaris, Taenia, schisto somiasis. 2 Skin diseases: typical appearances confirmed by biopsy e.g. dermatitis herpetiformis and pemphigus. 2 PAN: renal failure, neuropathy, angiography and ANCA positivity. 2 Sarcoid: multi-system features with non-caseating granulomata in biopsy of affected tissue or on BM biopsy; high serum ACE. 2 Hodgkin \200\231s: lymphadenopathy, hepatosplenomegaly \200\224BM or node biopsy. 2 Hypereosinophilic syndrome: history of allergy, cough, fever and pul- monary infiltrates on CXR, may be cardiac involvement. Eosinophils on blood movie have norm al morphology and granulation. Diagnosis on exclusion of similar causes. 2 Eosinophilic leukemia: eosinophils on blood movie have abnormal morphology with hyperlobular and hypergranular forms. BM heavily infiltrated with same abno rmal cells. Other signs of myeloproliferative disease may be present. 2 AML M4Eo: blasts with myelomonoblastic features on BM and blood movie (see p151). 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 141 White blood cell abnormalities 141 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 142 Basophilia and basopenia Basophils are found in peripheral blood and marrow ( \210 mast cells in tissues). Short li fespan (1 \200\2232d), cannot replicate. Degranulation results in hypersensitivity reaction s (IgE Fc receptors trigger), flushing, etc. Basophilia (peripheral blood basophils >0.1 109/L) 2 Myeloproliferative disorders \200\223 CGL. \200\223 Other chronic myeloid leukaemias. \200\223 PRV. \200\223 Myelofi brosis. \200\223 Essential thrombocythaemia. \200\223 Basophilic leukemia. 142 2 AML (rare). 2 Hypothyroidism. 2 IgE-mediated hypersensitivity reactions. 2 Inflammatory d isorders e.g. rheumatoid disease, ulcerative colitis. 2 Drugs e.g. oestrogens. 2 Infection e.g. viral. 2 Irradiation. 2 Hyperlipidaemia. Basopenia (peripheral blood basophils <0.1 109/L) 2 As part of generalized leucocytosis e.g. infection, inflammation. 2 Thyrotoxicosis. 2 Hemorrhage. 2 Cushing \200\231s syndrome. 2 Allergic reaction. 2 Drugs e.g. progesterone. 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 143 White blood cell abnormalities 143 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 144 Monocytosis and monocytopenia Bone marrow monocytes give rise to blood monocytes and tissue macrophages. Part of reticulo endothelial system (RES). Other compo- nents of RES: lung alveolar macrophages; pleural and peritoneal macrophages; Kupffer cells in liver; histiocytes; renal mesangial cells; macrop hages in lymph node, spleen and marrow. Contain 2 sets of granules (1) lysosomal (acid phosphatase, arylsulphatase and peroxidase), and (2) function of second set unknown. 144 Monocytosis (peripheral blood monocytes >0.8 109/L) Common 2 Malaria, trypanosomiasis, typhoid (commonest world-wide causes). 2 Post-chemothera py or stem cell transplant esp. if GM-CSF used. 2 Tuberculosis. 2 Myelodysplasia (MDS). Less common 2 Infective endocarditis. 2 Brucellosis. 2 Hodgkin \200\231s lymphoma. 2 AML (M 4 or M5). Discriminating clinical features 2 Malaria: identification of parasites on thick and thin b lood films. 2 Trypanosomiasis: parasites seen on blood movie, lymph node biopsy or blood cultures. 2 Typhoid: blood culture, fecal and urine culture and BM culture. 2 Infective endocarditis: cardiac signs and blood cultures. 2 Tuberculosis: AFB seen and cultured in sputum, EMU, bl ood or BM, tuberculin positivity on intradermal challenge, caseating granulomata on biopsy of affected tissue or BM. 2 Brucellosis: blood cultures and serology. 2 Hodgkin \200\231s: lymphadenopathy, hepatospl enomegaly, eosinophilia, biopsy of node or BM. 2 MDS: typical dysplastic features on blood movie or BM (see p218). 2 AML (M4 or M5): monob lasts on blood movie and BM biopsy. Skin and gum infiltration common, see p150. Monocytopenia (peripheral blood monocytes <0.2 109/L) 2 Autoimmune disorders e.g. SLE. 2 Hairy cell leukemia. 2 Drugs e.g. glucocorticoids, chemotherapy. 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 145 White blood cell abnormalities 145 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 146 Mononucleosis syndromes Definition Constitutional illness associated with atypical lymphocytes in the blood. Clinical features Peak incidence in adolescence: may be subclinical or acute presentation c onsisting of lym- phadenopathy splenomegaly hepatomegaly, palatal petechiae, maculopapul ar rash especially if given ampicillin. Rarely also pericarditis, myocarditis, encephalitis . Usually self- limiting illness but complications include lethargy persisting for months o r years (chronic fatigue syndrome), depression, autoimmune haemolytic anemia, thrombocytope nia, secondary infection and splenic rupture. fever, (cervical>axillary>inguinal), lethargy, sweats, anorexia, pharyngitis, 146 tender Causes EBV, CMV, Toxoplasma, Brucella, Coxsackie and adenoviruses, HIV sero- conversion ill ness. Pathophysiology In EBV related illness, EBV infection of B lymphocytes results in immortal- isation and generates a T cell response (the atypical lymphocytes) which controls EBV prol iferation. In severe immunodeficiency following pro- longed use of cyclosporin, oligoclonal EBV-related lymphoma may develop which usually regresses with reduction of immunosuppressi ve therapy but may evolve to a monoclonal and aggressive lymphoma e.g. after MUD stem cell transplant. In malarial Africa, EBV infection is associ- ated with an aggressive lymphoma \200\224Burkitt \200\231s lymphoma see p204. Diagnosis \200\223 hematological features 2 Atypical lymphocytes on blood movie (recognize d by the dark blue cyto- plasmic edge to cells and invagination (scalloping) around red blo od cells). 2 Usually lymphocytosis with mild neutropenia. 2 Occasionally anemia due to cold antibody m ediated haemolysis (anti-i) \200\224identify with cold haemagglutinin titre. 2 Paul Bunnell/monospot test for presence of heterophile antibody +ve when cause is EBV but only in the first few weeks. False +ves can occur in lymphoma. 2 4 bilirubin and abnormal LFTs. 2 Serological testing should include EBV capsid Ag, CMV Ig M, Toxoplasma titre, Brucella titre, HIV 1 and 2 Ag and Ab. 2 Immunophenotype of peripheral blood B lymphocytes shows poly- clonality (distinguishes from lymphoma and other lymphoproliferative disorders). Treatment Rest and symptom relief are mandatory. No other specific treatment has been shown to influence outcome. 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 147 White blood cell abnormalities 147 03-WBC abnormalities.qxd 10.12.2003 04.12 PM Page 148 This page intentionally left blank 148 04-leukemia.qxd 10.12.2003 04.12 PM Page 149 Leukemia 4 Acute myeloblastic leukemia (AML) 150 Acute lymphoblastic leukemia (ALL) 158 Chronic myeloid leukemia (CML) 164 Chronic lymphocytic leukemia (B-CLL) 168 Cell markers in chronic lymphoproliferative disorders 174 Prolymphocytic leukemia (PLL) 176 Hairy cell leukemia and variant 178 Sple nic lymphoma with villous lymphocytes (SLVL) 182 Mantle cell lymphoma 184 Large granular lymphocyte leukemia (LGLL) 186 Adult T-cell leukemia-lymphoma (ATLL) 188 S zary syndrome (SS) 190 04-leukemia.qxd 10.12.2003 04.12 PM Page 150 Acute myeloblastic leukemia (AML) Malignant tumor of haemopoietic precursor cells of non-lymphoid lineage, almost certainly a rising in the bone marrow. Incidence Commonest acute leukemia in adults. 3 per 100,000 annually. Increasing frequency with age (median 64 years; incidence 35/100,000 at age 90). Infrequent in children under 15 years. Etiology Unclear \200\224association with pre-existing myelodysplasia, previous cytotoxic c hemotherapy (particularly alkylating agents and epipodophyllotoxins), ionizing radiation, b enzene exposure, constitutional chromosomal abnor- malities (e.g. Down \200\231s (older pat ients) and Fanconi \200\231s syndromes) and smoking. 150 Diagnosis Made by examination of the peripheral blood movie and bone marrow ( \211 20% blas ts). Cytochemical stains, immunological markers, cytogenetic analysis and molecular markers are necessary to differentiate AML from ALL and further classify the disease in preparatio n for therapy. Morphological classification The French \200\223American \200\223British (FAB) system is ba sed on predominant dif- ferentiation pathway and degree of differentiation: Bone marrow showing myeloblasts in AML . AML: myeloblast with large Auer rod (top left). 04-leukemia.qxd 10.12.2003 04.12 PM Page 151 Leukemia M0 AML with minimal differentiation (SB & MPO cytochemistry negative but myeloid immunophenoty ping; may also express CD4 & CD7); 3% of cases. AML without maturation (<10% promyelocytes/ myelocytes or monocytes; may have Auer rods) 20% of cases. AML with maturation ( \211 10% p romyelocytes/myelocytes; < 20% monocytes; may have Auer rods; t(8;21)) commonest subtype: 3 0% of cases. Acute promyelocytic leukemia (>30% promyelocytes; multiple Auer rods (faggot c ells); t(15;17)) 10% of cases. Microgranular variant of APL (high WBC count; minimal granul ation; Auer rods rare; t(15;17)). Acute myelomonocytic leukemia (mixed myeloid (>20% blasts & promyelocytes) & monocytic ( \211 20%) maturation; monocytic cells are non-specific este rase positive; may have Auer rods) 20% of cases. M4 variant with 5 \200\22330% eosinophils; associated with inv(16) chromosome abnormality. 5% of cases Acute monoblastic leukemia (po orly differentiated subtype with \211 80% monocytoid cells of which \211 80% are monoblas ts; Auer rods unusual) 10 \200\22315% cases are M5a or M5b. Acute monocytic leukemia (diffe rentiated subtype with \211 80% monocytoid cells including NSE-positive cells with typical monocytic appearance; Auer rods rare) Acute erythroleukaemia (myeloblasts sometimes with A uer rods plus \211 50% bizarre often multinucleated erythroblasts; erythroblasts often PAS -positive) 3 \200\2235% of cases but 10 \200\22320% of secondary leukaemias. Acute megakary oblastic leukemia (difficult to diagnose morphologically; often dry tap due to fibrosis; re quires immunophenotyping with anti-platelet antibodies or electron microscope analysis of p latelet peroxidase) rare. M1 M2 151 M3 M3v M4 M4Eo M5a M5b M6 M7 Cytochemistry Former mainstay of leukemia diagnosis; Sudan black (SB), myeloperoxi- dase (M PO) and esterase (chloroacetate and non-specific esterase) stains are positive in AML and n egative in ALL (<3% blasts positive). Non-spe- cific esterase (NSE) is positive in monocyti c cells. World Health Organization (WHO) classification of acute myeloid leukemia Although the FAB c lassification has provided a morphological classification of AML for almost 30 years the co rrelation between morphology and both genetic and clinical features is imperfect. The WHO c lassification attempts to correlate morphological, genetic and clinical features to cate- g orise cases of AML into unique clinical and biological subgroups. In the WHO classification the blast threshold for the diagnosis of AML is reduced from 30% to 20% BM blasts (i.e. most patients previously diag- 04-leukemia.qxd 10.12.2003 04.12 PM Page 152 nosed as RAEB-t will be classified as AML with multilineage dysplasia) and patients with t( 8;21)(q22;q22), inv(16)(q13q22), t(16;16)(p13;q22) or t(15;17)(q22;q12) should be con- side red to have AML regardless of the blast percentage. clonal recurring abnormalities WHO classification of acute myeloid leukemia Acute myeloid leukemia with recurrent genetic abnormalities 2 Acute myeloid leukemia with t (8;21)(q22;q22), (AML1/ETO) 2 Acute myeloid leukemia with abnormal BM eosinophils and