Pathology > Basic Hematology > White Cell Disorders > Benign White Cell Disorders: Qualitative Disorders

Benign White Cell Disorders: Qualitative Disorders

Qualitative or morphologic abnormalities of leukocytes may be hereditary or acquired, permanent; or transient.

Hypersegmentation, the presence of abnormally increased nuclear lobulation, is one of the first hematologic abnormalities seen in megaloblastic anemia. Normal mature circulating neutrophils have an average of 3 lobes and always fewer than 5 lobes. Eosinophils have fewer than 4 lobes and basophils have fewer than 3 lobes. More than 3 cells having 5 lobes or a single cell with 6 lobes found in the course of a 100 cell differential is evidence of hypersegmentation. Hypersegmentation is sometimes referred to as a myeloid "right shift". Hypersegmentation may accompany other disorders in which there is a disturbance of maturation, such as iron defiency.

Myeloperoxidase deficiency (MPO) is a common (1:2,000 individuals) autosomal recessive absence of myeloperoxidase enzyme in neutrophil and monocyte granules. Although people with concommittant MPO deficiency and diabetes mellitus may develop Candidiasis, MPO deficiency in most people is of no clinical consequence.

Acquired MPO deficiency may be seen in acute myeloid leukemia, myelodysplastic syndromes, and lead poisoning.

MPO Deficiency:

1)Wright's stained neutrophil;

2)MPO stained neutrophil;

3)MPO stained eosinophil;

Pelger-Huet anomaly is a congenital autosomal dominant disorder in which granulocyte nuclei fail to segment normally. In the homozygote state the nucleus is round. In heterozygotes most granulocytes have bilobed nuclei ("pince-nez" cells) resembling bands. The trait is benign and occurs in 1 in 6,000 people. Cell function is normal.

An acquired or pseudo-Pelger-Huet anomaly is seen in myelodysplastic disorders and following drug therapy, and may accompany leukemia and certain infections.

Toxic granulation is found in severe inflammatory states. The toxic granules are azurophilic, usually found in the promyelocyte, metamyelocyte, band, and segmented stages. The toxic granulation is thought to be due to impaired cytoplasmic maturation,in the effort to rapidly generate large numbers of granulocytes.

L Dohle bodies are single or multiple blue cytoplasmic inclusions. They represent remnants of rough endoplasmic reticulum from earlier maturational stages. They are associated with myeloid "left shifts" and are seen in conjunction with toxic granulation.

May-Hegglin anomaly is a rare autosomal dominant abnormality characterized by large pale basophilic inclusions resembling Dohle bodies and appear to be altered RNA. Giant platelets, and sometimes thrombocytopenia are associated with this. The anomaly is usually benign but may be associated with bleeding.

The Chediak-Higashi syndrome is a rare autosomal recessive condition associated with abnormally large leukocyte granules resulting from fusion of lysozymes. This disorder may affect granulocytes, leukocytes, and monocytes. Chemotaxis and phagocytosis is defective. Platelets lack dense granules and platelet function is abnormal. Giant melanosomes in occular and skin tissues result in hypopigmentation.

The Alder-Reilly anomaly is associated with the genetic mucopoly- saccharidoses. Patients with mucopolysaccharidoses lack the lysozymal enzymes necessary to break down mucopolysaccharides. Dense azurophilic granules, resembling toxic granulation in neutrophils, are seen in all leukocytes. Most characteristic of these disorders are the metachromatic granules surrounded by a clear zone seen in lymphocytes.

As you can see, qualitative and quantitative evaluations of leukocytes are useful 1) to establish diagnoses, 2) to prognosticate, and 3) to evaluate therapy.

You should now be aware of the major causes and mechanisms, and clinical manifestations of leukocytoses and leukocytopenias. You should also recognize the major morphologic white cell abnormalities and know their clinical significance.

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