Hematopathology

Lecture 3
 WBC disorders

Learning objectives

1. Introduction to normal WBC morphology and functions.

2. Benign WBC disorders mostly of count abnormalities.
3. Dysfunctional abnormality of leucocytes.
4. General evidences and diagnosis of mononucleosis syndrome.
5. Classification and general principle of leukemia.
6. Acute leukemia, definition, classification, features and diagnostic
approach.
 LO1

5 types of Leucocytes (WBC) present in peripheral blood

are:

o Neutrophils
o Lymphocytes
o Monocytes
o Eosinophils
o Basophils.
 LO1
Neutrophil: usually 3-5 segments nucleus with
neutrophilic granules in the cytoplasm
(pink-blue granules).

Eosinophil: usually 2 segments nucleus with

eosinophilic granules in the cytoplasm
(red granules).

Basophil: usually 2 segments nucleus with

basophilic granules in the cytoplasm
(dark-blue granules).
 LO1

Monocyte: larger cell, mononuclear cell, convoluted

nucleus, usually with no granules in the cytoplasm
(grey cytoplasm).

Lymphocyte: small cell, mononuclear cell, round

nucleus, usually with no granules in the cytoplasm
(basophilic cytoplasm).
 LO1

Monocyte when migrate to

the tissue will convert to
macrophage

Macrophage

B-lymphocyte when
activated by antigen will
convert to plasma cell which
produce Ig.

Plasma cell
 LO1
WBC synthesis from BM by process of leucopoiesis.

Total leukocytes count is 4-11 × 109/L. (4000-1000 cells / cu mm).

Half life around 1 day (few hrs to days) and may reach many years. All
WBC are transient pass in blood and finally home in the tissue.

Granulocytic cells: cell which contain granules in their cytoplasm

(Neutrophil, Eosinophil, Basophil).

Mononuclear cells: cell which usually lack granules in their

cytoplasm (Monocyte, Lymphocyte).
Normal differential WBC count in adult is: LO1

Neutrophils 40-80 %.
Lymphocytes 20-40 %.
Monocytes 2-10 %.
Eosinophils 1-5 %.
Basophils 0-1 %.

Normal absolute WBC count in adult is:

Neutrophils 2-8 x 109/L

Lymphocytes 1-4 x 109/L
Monocytes up to 1 x 109/L
Eosinophils up to 0.5 x 109/L
Basophils up to 0.1 x 109/L
 LO1
Example:
Total WBC count is 6 x 109 /L.
Neutrophils 60 %.
Lymphocytes 34 %.
Monocytes 4 %.
Eosinophils 2 %.
Basophils 0 %.

What is the absolute neutrophil and lymphocyte count ?

Answer:
– Absolute neutrophil count = 6 x 60 = 3.6 x 109 /L.
– Absolute lymphocyte count = 6 x 34 = 2.04 x 109 /L
 LO1
Function of WBC

• Neutrophil: engulf bacteria and other organism in acute infection

by phagocytosis.
• Eosinophil: mediate allergy and parasitic infestation.
• Basophil: mediate allergy.

o Lymphocytes: (B and T lymphocytes) roles in immunity and

defense against cancer and viral infection.

o Monocyte: engulf bacteria specially in chronic infection and

inflammation. It convert to macrophage in the tissue.
 LO2
WBC disorder could be:

Benign WBC disorder:

• Abnormal WBC count.
• Abnormal WBC function.
• Infectious Mononucleosis Syndromes

Malignant WBC disorder:

• Acute leukemias.
• Chronic leukemias.
• Myeloma.
• Lymphomas.
 LO2
Abnormal WBC count

• Leukopenia: WBC < 4 000 cells / cu mm

• Leukocytosis: WBC > 11 000 cells / cu mm

• Neutrophilia: high neutrophil count

• Neutropenia: low neutrophil count

• Lymphocytosis: high lymphocyte count

• Lymphopenia: low lymphocyte count

• Monocytosis: high monocyte count

high eosinophil count.
• Eosinophilia:
high basophil count
• basophilia:
 LO2
Neutrophilia

Definition: When neutrophil percentage > 80% of total WBC or absolute

count > 8 x 109/L.

Causes:
- Physiological: vigorous exercise, pregnancy and newborn.
- Pathological:
• Acute pyogenic bacterial infection, virus, fungal and parasitic infections.
• Rheumatic and autoimmune diseases.
• Hematological and non-hematological malignancy.
• Inflammation, tissue necrosis and metabolic disorders.
• Drugs: steroid and epinephrine.
• Acute hemorrhage or hemolysis
 LO2

Left shifting: mean the presence of WBC precursor (immature cells)

in the blood which should be still in the BM.

Leukemoid reaction: it reactive and excessive leukocytosis usually >

50 × 109/L, characterize by immature cells in peripheral blood and
associated with severe infections, severe hemolysis and metastatic
cancers. Mainly occurs in children.
 LO2
Neutropenia

Definition: When neutrophil percentage < 40% of total WBC or

absolute count < 2 x 109/L.

Causes:
• Benign familial.
• Congenital neutropenia like Kostmann’s syndrome .
• Secondary to viral infections and fulminated bacterial infections.
• Autoimmune disease.
• Drug induced; most common adult cause of isolated neutropenia.
• Bone marrow defect for any cause.
 LO2
Lymphocytosis

Definition: When lymphocyte percentage > 40% of total WBC or

absolute count > 4 x 109/L.

Causes:
• Acute viral infections.
• Chronic infections like tuberculosis.
• Autoimmune disorders and drug allergy.
• Lymphomas or leukemias.

Lymphopenia: When lymphocyte percentage < 10% of total WBC or

absolute count < 1 x 109/L.
It may occur with immune deficiency, some acute viral or bacterial
infections
 Eosinophilia LO2

Eosinophil percentage > 5 % of total WBC or absolute count > 0.5 x 109/L.

Causes:
• Allergic disorders.
• Parasitic infestation.
• Drug reactions.
• Hematological diseases like in CML.
• Hodgkin disease.

Basophilia
• Allergic and inflammatory disorders.
• Endocrinopathy as hypothyroidism.
• Viral infection as chicken pox.
• Iron deficiency anemia.
• Malignant association as CMPDs.
 LO2

Monocytosis

• Chronic bacterial infections.

• Collagen vascular diseases.
• Chronic steroid therapy.
• Some malignancy.
 LO3
Abnormal WBC function

• Either due to inherited or acquired causes.

• Patient usually presented with recurrent infection even with normal
WBC count.
• Special tests are used to assess phagocytic disorders or immune
deficiency disease.
 LO4
Infectious Mononucleosis Syndrome

A clinical syndrome, characterized by blood lymphocytosis with many

reactive atypical lymphocytes.
In most instances an infectious agent lies behind this syndrome; mainly
EBV infection, and so called infectious mononucleosis.

Etiological Agents associated with monouncleosis syndrome are:

• Epstein-Barr virus (most common).
• Cytomegalovirus.
• HIV.
• Hepatitis viruses.
• Toxoplasma gondii.
 LO4

Clinical features:
• Occur in minority of infected individuals, mainly it subclinical.
• Malaise, fatigue, headache, fever, lymphadenopathy, splenomegaly,
hepatomegaly, pharyngitis, and tonsillitis.

Laboratory findings:
• CBC showing absolute lymphocytosis, with many atypical reactive
lymphocytes appear on peripheral blood.
• Serology for heterophil antibody using Paul-Bunnell test or monospot
test.
 LO4
Leukemia
Leukemia is the malignancy of WBC and usually associated with high
WBC count so called leukemia (mean white color blood).

Classification:
• Acute leukemia
1. Acute Lymphoid Leukaemia (ALL)
2. Acute Myeloid Leukemia (AML)

• Chronic leukemia:
1. Chronic Lymphoid Leukaemia (CLL)
2. Chronic Myeloid Leukemia (CML)
 Acute leukemia LO5

Definition: is a clonal disorder, characterized by abnormal

proliferation of blast cells in the bone marrow and spillage into the
peripheral blood and other organs. Acute leukemia by definition mean
blast cells ≥ 20 % of cells in peripheral blood or BM according to WHO
diagnostic criteria.

Pathogenesis: Acute leukemia are characterized by genetic defect at

level of stem cells or progenitor cells leading to proliferation without
maturation of blast cells.

Etiology of AL: unknown, but with several factors in association:

• Irradiation.
• Chemicals.
• Genetic factors.
• Chronic clonal hematological disorders.
• Oncogenic viruses.
 Normal leucopoiesis LO5

Stem Progenitor Precursor cell Mature WBC

Neutrophil, lymphocyte,
cells cells (Blast cell) monocyte, eosinophil, basophil.

Genetic defect at stem cells lead to

proliferation without maturation at stage
of blast cells.
Acute leukemia

Blast cell
Etiology of acute leukemia (unknown) ?? LO5
but may be associated with:

Ionizing radiation Genetic factors

Oncogenic viruses Chemicals

 LO5
Classification of Acute Leukemias

1. Acute Lymphoid Leukaemia (ALL): defect in the line of

lymphocytes with proliferation of lymphoblast.

2. Acute Myeloid Leukemia (AML): defect in the line of

granulocytes with proliferation of myeloblast.

According to morphology and cytochemistry of blast cells, acute

leukemia may be subclassify into:

ALL: L1, L2, and L3.

AML: M0, M1, M2, M3, M4, M5, M6, and M7.
Clinical features:

• Acute leukemia of rapid acute presentation.

• Childhood acute leukemia (<15 yrs) mainly of ALL type while adult
acute leukemia (>15 yrs) mainly of AML type.
• Features of anemia (due to marrow infiltration by blast cells).
• Bleeding (thrombocytopenia due to marrow infiltration by blast cells).
• Infections (reduce in normal WBC due to marrow infiltration by blast
cells).
• LAP, mediastinal enlargement, organomegaly more with ALL.
• CNS involvement and testicular infiltration more with ALL.
• Gum hypertrophy more with AML.
• DIC is a special feature of AML-M3.
Principle methods in acute leukemia diagnosis:

CBC and blood film (required to all cases):

• Usually anemia and thrombocytopenia.
• WBC usually markedly increased may reach 200-300 x 109/L, but
may be normal or decrease.
• Majority of leucocytes on film are blasts cells.

BM examination (required to all cases): showing extensive infiltration

of BM by blasts cells.
Other investigations used in indicated cases to confirm the
diagnosis, subtyping of leukemia and prognostic significant like:

• Cytochemistry (stain the blast cells with chemical stains to

differentiate their types).
• Cytogenetics (chromosomal analysis).
• Molecular analysis (genetic study).
• Immunophenotyping (study the antigens on malignant cells).
• Electron microscope.
Blood film and bone marrow slides
showing infiltration of Blast cells.

Bone marrow examination

Cytochemistry

Cytogenetic
Immunophenotype

Electron microscope
 Treatment of acute leukemia
o Supportive management.
o Chemotherapy.
o BM or stem cell transplantation.

Chemotherapy

Stem cell transplantation

Good Luck