Blood Film Examination(Part Five)

White Blood Cells Disorders

Definition of Leukemia:

Abnormal neoplastic accumulation of blood cells in BM, organs, & PB.

Clinical Classifications:

Acute Leukemia: Usually fatal within 3 months. Characterized by the predominance of blasts of the

cell type involved. Subacute leukemia:

Have a longer patient survival of 3-12 months. Usually have a clinical picture of acute leukemia.

Chronic Leukemia: Have a survival of > one year. Blasts are elevated but are usually less than 5%. Maturation within a cell line still occurs.

Leukocyte Maturation:

The morphology of leukocyte maturation is important to know for differentiating cells of each maturation stage.

The maturation stages of granulocytes are: myeloblast, promyelocyte, myelocyte, metamyelocyte, neutrophil band, segmented neutrophil.

The maturation stages of monocytes: monoblast, promonocyte, monocyte.

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The maturation stages of lymphocytes are: lymphoblast, prolymphocyte, lymphocyte

Morphology of Granulocyte MaturationType of Cell

Nucleus Cytoplasm Nuclear/Cytoplas-mic RatioN/C

Normal Range in Peripheral Blood

Myeloblast -Round.-Centralized.-Smooth chromatin-2-5 nucleoli.

-Deep basophilic.-No granules.

4:1 None

Pro-Myelocyte

-Variable shape.-Centralized.-Chromatin begins to condense.-Nucleoli are still visible.

-Basophilic.-Many azurophilic granules.

2:1 None

Myelocyte -Round or elongated.-Often eccentric.-Slightly condensed. chromatin.-Faint nucleoli.

-Mixture of basophilic and eosinophilic.- Basophilic or eosinophilic granules.

1:1 None

Meta-Myelocyte

-Kidney-shaped.-Slightly condensed chromatin.-No nucleoli.

-Beige or salmon.-Many granules.

1:1 None

Band -Uniform or elongated.-U-shaped.-Condensed chromatin.-No nucleoli.

-Beige or salmon.-Faint granules.

1:1 – 1:2 0% - 6%

Segmented Neutrophil

-Nucleus with 2-4 lobes.-Highly condensed chromatin.-No nucleoli.

-Beige or salmon.-Faint granules.

1:2 50% - 75%

Eosinophil -2-3 lobes.-Condensed chromatin.-No nucleoli.

-Beige or salmon.-Many large, round, orange granules.

1:2 0% - 4%

Basophil -2-3 lobes.-Condensed chromatin.

-Beige or salmon.-Many large,

1:2 0% - 2%

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-No nucleoli. round, purple granules.

The Most Common Types of Leukemia:

Chronic Myelogenous Leukemia (CML):

Occurs mainly in middle-aged adults with a slow and unrevealing onset of symptoms.

A characteristic differential count showing complete maturation of granulocytes from myeloblasts to segmented neutrophils with the majority being myelocytes and segmented neutrophils.

Laboratory Profile:

WBC count usually higher than 50 X 109/L and possibly as high as 300 X 109/L.

Myeloblasts are less than 10%. Basophilia, Eosinophilia, Monocytosis. Normochromic normocytic anemia due to

decreased RBC production. Thrombocytosis in the early phases of the disease

and thrombocytopenia in the late phases. NRBCs are common.

Acute Myelogenous Leukemia (AML):

A disease of childhood. WBC count is around 200 X 109/L. AML represents seven subtypes (M1 to M7) and each

type has its characteristic features.

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Chronic Lymphocytic Leukemia (CLL):

A slowly progressing malignancy and is commonly discovered incidentally or only in the late stages of the disease.

Most commonly seen in adults with a mean age of occurrence at 55 years.

It is twice as common in men as compared with women.

Laboratory Profile: leukocytosis ranging from 10-150 X 109/L with 80%

to 90% lymphocytes. Smudge cells are commonly found. < 10% immature lymphocytes. Lymphocytes have a characteristic morphology:

o The nuclear chromatin is coarsely condensed.o Nucleoli may be seen.o Lymphocytes show minimal size and shape

variation.o The cytoplasm is small to moderate in amount.

Acute Lymphocytic Leukemia (ALL):

A rapidly progressing malignancy with the predominance of immature lymphocytes.

Mainly a disease of childhood, with a peak incidence at 4 years. The second peak of incidence is in young adults between 20 and 40 years.

Onset of leukemia is sudden, with symptoms of anemia, bleeding, fever and fatigue.

Laboratory Profile: Normochromic normocytic anemia. NRBCs are found. The WBC count could be:

o Very high.

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o Slighlty elevated.o Most often normal or decreased.

The predominant cell is the lymphoblast. The serum level of uric acid is often elevated.

Other White Blood Cell Disorders:

Physiologic Leukocytosis:

It is produced by factors that do not involve tissue damage: Excessive exercise. Hypoxia. Stress.

Leukomoid Reaction:

A non leukemic leukocytosis with a WBC count > 30 X 109/L. It is characterized by the lack of myeloblasts in PB. A shift to the left with increased band forms, few

metamyelocytes, & myelocytes in PB. The LAP score level is increased, which is a distinguishing

factor as compared with leukemia. Leukomoid reactions are most commonly encountered in

children with: Infections: pneumonia, meningitis and tuberculosis. Severe hemolysis. Metastatic cancer.

Miscellaneous Disorders and Conditions:

Neutrophilia with a Shift to the Left:

Bacterial infections. Febrile illnesses. Tissue destruction: burns, fractures, myocardial infarctions and surgery.

Eosinophilia and Basophilia:

Allergic diseases. Parasitic infections.

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Monocytosis:

Brucellosis. During the recovery phase of infections.

Lymphocytosis:

Viral infections.

Congenital and Acquired Disorders of Neutrophils:

Toxic Granulation:

Most commonly found in severe infections or other toxic conditions.

Appears as tiny, dark blue-to-purple cytoplasmic granules in the metamyelocyte, band, or segmented neutrophil stages.

Cytoplasmic Vacuoles:

Cytoplasmic vacuoles are also signs of toxic changes.

Hereditary Hypersegmentation:

A disorder in which the majority of the neutrophils have four or more lobes.

This disorder must be differentiated from the hypersegmentation of megaloblastic anemia.

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Examples on Reporting Blood Film Examination

Patient A:

Normocytic red blood cells with slight hypochromia.Leukocyte count is slightly increased with a shift to the left. Basophilia and many immature cells found.Platelet count is decreased.Follow up and further hematological investigations are recommended.

Patient B:

Microcytic hypochromic red cells.Marked lymphocytosis. Undifferentiated cells seen.Platelets appear normal.Follow up and further hematological investigations are recommended.

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