rainwater@mymelody.com || 1st semester, AY 2011-2012

4 – Leukocytic Disorders

Leukocytes

• Protection from non-self-cells and from altered self-cells • Two broad groups:

o Phagocytes – granulocytes, monocytes o Immunocytes – lymphocytes, plasma cells

Formation of Neutrophil and Monocyte Phagocytes Eosinophils and basophils are also formed in the marrow in a process similar to that for neutrophils.

Granulopoiesis Proliferative/mitotic production: progenitor cells, myeloblasts, promyelocytes, myelocytes Post-mitotic maturation compartment: metamyelocytes, bands, segmenters Reserve/storage pool In bloodstream, two pools: 1) circulating; 2) marginating Kinetics: 6-10 hours in circulating pool 4-5 days in tissue 6-10 days – bone marrow Neutrophil Kinetics CSF, colony-stimulating factor. G, granulocyte. IL, interleukin. M, monocyte. SCF, stem cell factor.

White cells: Normal blood counts

TOTAL LEUCOCYTES Adults 4.0 – 11.o X 109/L Neonates 10.0 – 25.0 X 109/L 1 year 6.0 – 18.0 X 109/L 4 – 7 years 6.0 – 15.0 X 109/L 8 – 12 years 4.5 – 13.5 X 109/L

Reference Ranges for the Differential Leukocyte Count in Adults Cell Proportional Count

(%)n Absolute Count (X109/L)

Neutrophils 37-80 Adults: 1.8 – 7.0 Pedia: 1.0 – 8.5

Lymphocytes 10-50 Adults: 1.5 – 4.0 Pedia: 1.5 – 8.8

Monocytes 0 - 12 .03 - .9 Eosinophils 0 – 9.5 0.0 – 0.67 Basophils 0 – 2.5 0.0 – 0.20

Factors influencing neutrophil count: • Rate of inflow of cells from the marrow

(mitosis/proliferation, maturation/storage release) • Proportion of neutrophils between the marginal (cells

adhering to vessels walls) granulocytic pool and the circulating (non-adhering cells) granulocytic pool

• Rate of outflow of neutrophils from the blood (migration from and through vessels into tissues, both randomly and at sites of inflammation, infection, etc.)

Host factors that can modify degree of neutrophil response:

• Age: children respond more intensely than adults • Virulence of infecting agent • Hematinic deficiency &/or marrow failure

rainwater@mymelody.com || 1st semester, AY 2011-2012

Leucocyte Count

• NV: 4-11 x 109/L

• Calculation of absolute values for each leucocyte class is encouraged

Absolute vs. relative leucocytosis

• Use of absolute values has made the definition of normal range more precise and provides best value for determining abnormality

Leucocytosis

• Increase in WBC count above upper limit of normal for age and sex

• Specify: neutrophilia, lymphocytosis, monocytosis, eosinophilia, basophilia

Leucopenia

• Decrease in total WBC count below the lower limit of normal for age and sex

• Neutropenia, lymphocytopenia

NB: Increase in any cell type maybe clinically important but decrease is usually significant only for neutrophils.

Neutrophilic Leucocytosis • Absolute count >7.5 X 109/L

bands & neutrophils • Pathophysiologic mechanisms:

1. Increased cell production 2. Accelerated release of cells from marrow into blood 3. Shift from marginal to circulating pool 4. Reduced egress of neutrophils from blood to tissues 5. Combination

Causes of Neutrophilia

• Increased production: chronic disorders - infections, tumors, inflammation, endocrinopathies, myeloproliferative disorders

• Increased production and peripheral cell survival: CML

• Accelerated release from the marrow: stress, intoxication, infections, inflammation, corticosteroids, endotoxins

• Increased shift from marginal pool to circulating pool: stress, intoxication, hypoxia, infections, exercise, adrenalin

• Decreased egress from circulating pool: corticosteroids

• “Shift to the left”: increase in immature peripheral blood granulocytes, usually seen in acute infection

• Leukemoid reaction: reactive and excessive leucocytosis usually characterized by release of immature cells(myeloblasts, promyelocytes, myelocytes)

- WBC >50 x 109/L with shift to the left - Conditions: severe and chronic infection,

severe hemolysis , metastatic CA - High leucocyte alkaline phosphatase (LAP)

score

Causes of Neutrophilic Leukocytosis • Bacterial infections (especially pyogenic bacterial,

localized or generalized) • Inflammation and tissue necrosis (e.g., myositis,

vasculitis, cardiac infarct, trauma)

• Metabolic disorders (e.g., uremia, eclampsia, gout, acidosis)

• Neoplasms of all types (carcinoma, lymphoma, melanoma)

• Acute hemorrhage or hemolysis • Drugs (e.g., corticosteroids, lithium, tetracycline) • Chronic myelogenous leukemia, myeloproliferative

diseases such as polycythemia vera, myelofibrosis, essential thrombocytosis

• Treatment with myeloid factors (e.g., G-CSF, GM-CSF)

• Rare inherited disorders

• Asplenia

Neutropenia: ANC<1.5 x 109/L

Degree of Neutropenia and ANC

Normal: > 1.5 x 109/L Mild: ANC 1.0-1.5 x 109/L Moderate: ANC .5-1.0 x 109/L (some increased risk for infection)

Severe: ANC < .5 x 109/L (significant risk of infection)

Mechanisms for Production of Neutropenia

• Decreased flow of neutrophils from the marrow due to lack of production or ineffective production (i.e., proliferation or production defect)

• Increased removal of neutrophils from the blood (survival defect)

• Altered distribution between circulating and marginal granulocytic pools

• Combination of factors

Neutropenia and the risk of infection • ANC <1.5 x 109/L • Risk of infection depends on 3 factors

1. Absolute neutrophil count (ANC) 2. Neutrophil reserve in the bone marrow 3. Duration

• Neutrophil reserve: normal if with the ff: – No prior cytotoxic therapy – Appropriate ANC increases in response to

infections or stress

– Normal bone marrow biopsy

• Duration of neutropenia

– Periodic or episodic (e.g. post chemo)

– Chronic

Causes of Neutropenia

• Bone marrow failure

– Aplastic anemia; leukemia; myelodysplasia; myelofibrosis; marrow infiltrations; megaloblastic anemia

• Splenomegaly

• Infections • Immune-related

• Drug-induced

Some Drugs Associated with Neutropenia

• Anti-inflammatory: Aminopyrine, phenylbutazone

• Antibacterial: Chloramphenicol, sulfas, penicillins, cephalosporins, antivirals vs AIDS

• Anticonvulsants: Phenytoin, phenobarbital • Antithyroids: Carbimazone • Phenothiazines: Chlorpromazine, promethazine • Cardiac meds: antiarrhythmics, digoxin, diuretics, ACEI • Chemotherapy • Tolbutamide, phenidione, H2 antagonists

rainwater@mymelody.com || 1st semester, AY 2011-2012

Lymphocytosis • Absolute count: >4.0 X 109/L • Maybe categorized as either

monoclonal or polyclonal • Review of peripheral smear important:

- reactive lymphocytes seen in viral infections

- large granular lymphocytes in large granular lymphocytic leukemia

- smudge cells seen in CLL

- blasts of acute leukemia

Causes of Lymphocytosis

• Monoclonal lymphocytosis: due to underlying lymphoproliferative disorders - lymphocytes are increased due to an intrinsic defect in the expanded lymphocyte population Ex: Lymphoproliferative disorders

• Polyclonal lymphocytosis: secondary to stimulation or reaction to factors extrinsic to the lymphocyte. (Inflammation and/or infections)

Acute infections: Rubella, pertussis, mumps, infectious mononucleosis, acute infectious lymphocytosis Chronic infections: Tuberculosis, brucellosis, infective hepatitis, syphilis

• Immune mediated: drug sensitivity, vasculitis, graft rejection, Grave’s, Sjogren’s

• Stress – acute, transient

Lymphocytopenia

• Absolute count: Adults < 1.0 X 109/L

Children < 2.0 X 109/L

Causes of Lymphocytopenia

• Destruction – radiation, chemotherapy, corticosteroids

• Debilitative – starvation, aplastic anemia, terminal cancer, collagen vascular disease

• Infectious- viral hepatitis, influenza, typhoid fever, TB

• Abnormal lymphatic circulation – intestinal lymphangiectasia, obstruction, thoracic duct drainage/rupture, CHF

Monocytosis • Absolute count >0.8 X 109/L

• Causes: >50% due to hematologic disorders (e.g, AML, MDS, lymphomas)

10% inflammatory and immune disorders

8% malignant diseases

Causes of Monocytosis

• Infectious – tuberculosis, subacute bacterial endocarditis, syphilis, protozoan, rickettsial

• Recovery from neutropenia • Hematologic – leukemias, myeloproliferative

disorders, lymphomas, multiple myeloma

• Inflammatory – collagen vascular diseases, chronic ulcerative colitis, sprue, myositis, polyarteritis, temporal arteritis

• Others – solid tumors, immune thrombocytopenic purpura, sarcoidosis

Eosinophilia

• Mild: <1500 cells/uL

• Moderate: 1500-5000 cells/ uL

• Severe: >5000 cells/uL

Causes of Eosinophilia

• Allergic diseases especially hypersensitivity of the atopic type (e.g., bronchial asthma, hay fever, urticarial and food sensitivity)

• Parasitic diseases (e.g., amoebiasis, hookworm, ascariasis, tapeworm infection, filariasis, schistosomiasis, trichinosis)

• Recovery from acute infection

• Certain skin diseases (e.g., psoriasis, pemphigus and dermatitis herpetiformis, urticarial and angioedema, atopic dermatitis)

• Inflammatory-eosinophilic fasciitis, Churg-Strauss syndrome, polyarteritis nodosa, vasculitis, serum sickness

• Non-parasitic infections – systemic fungal, scarlet fever, chlamydial pneumonia of infancy

• Respiratory – pulmonary eosinophilic syndromes (Ioeffler’s, tropical pulmonary eosinophilia), Churg-Strauss syndrome

• Neoplastic – CML, Hodgkin’s lymphoma, T-cell lymphoma

• Idiopathic hypereosinophilic syndromes

• Others – certain drugs, hematologic and visceral malignancies, GI inflammatory diseases, sarcoidosis, Wiskott-Aldrich

• Primary hypereosinophilic syndrome Criteria: >1500 eosinophils/uL for more than 6 months

Absence of an underlying cause of eosinophilia despite extensive evaluation

Presence of end-organ damage or dysfunction related to eosinophilia: skin, heart, nervous system

Basophilia

• Absolute count >0.2 X 109/L

• Causes: – Myeloproliferative diaseases

– Allergic – food, drugs, foreign proteins

– Infectious – variola, varicella

– Chronic hemolytic anemia

• Especially post-splenectomy

– Inflammatory – collagen vascular diseases, ulcerative colitis

rainwater@mymelody.com || 1st semester, AY 2011-2012

Acute Leukemia

• Characterized by accumulation of malignant white cells (blasts) in the blood and bone marrow

• Defined by presence of >20% blasts in the blood and bone marrow

• Laboratory features 1. Anemia 2. Thrombocytopenia 3. Leukocyte count

- May be high, low, normal - <5000/uL in half of patients

- Note for “absolute lymphocytosis”

- High WBC count with high lymphocyte %

• Can present with pancytopenia

• Myelogenous vs. lymphocytic

• May be difficult to differentiate based on clinical manifestations and simple morphology

• Other tests

o Cytochemical stains

o Immunophenotyping

Flow cytometry

Chronic Myelogenous Leukemia

Laboratory features

• A complete spectrum of myeloid cells in the peripheral blood (WBC’s in all stages of maturation). The levels of neutrophils and myelocytes exceed those of blasts and promyelocytes.

• Increased basophils

• Normochromic, normocytic anemias

• Platelet count frequently increased but may be normal or decreased

• Leucocyte alkaline phosphatase is low

• Bone marrow is hypercellular with myeloid hyperplasia

• Ph chromosome on cytogenetic analysis (conventional or FISH)

• Serum uric acid is usually elevated

Chronic Lymphocytic Leukemia

Laboratory Evaluation

• Absolute lymphocytosis

• Absolute neutrophil count is variable

• Anemia or thrombocytopenia

o 30% of patients

o 15% Hgb less than 11mg/dL or platelets less than 100,000