[CHEDIAK-HIGASHI SYNDROME]. Chediak-Higashi syndrome is a rare autosomal recessive disorder characterized clinically by partial oculocutaneous albinism due to defects in melanin granules and recurrent pyogenic bacterial infections due to abnormalities in granulocytes. The basic defect is in microtubules resulting in fusion of lysosomal granules. All white blood cells contain abnormally giant granules. This image shows a normally segmented neutrophils with giant azurophilic granules.

[CHEDIAK-HIGASHI SYNDROME]. Chediak-Higashi syndrome may also show abnormalities of nuclear lobation in neutrophils as seen in this example of a bi-lobed neutrophil. Note also abnormally large secondary granules. Because of abnormal granules there is defective and delayed release of bactericidal lysosomal proteins leading to poor ability to fight bacterial infections. Neutrophil number is also decreased in addition to defective granulation which heightens the susceptibility to infections. Thrombocytopenia is also seen in these patients.

[CHEDIAK-HIGASHI SYNDROME]. Eosinophils also show abnormally giant granules as seen in this example. Functional abnormalities of eosinophils also lead to defects in chronic inflammation. Basophils and monocytes are also affected and show giant granules and defects in inflammatory and immune functions. Note that giant abnormal pseudo Chediak-Higashi granules can occasionally be seen in certain acquired hematologic disorders such as in myeloblasts in acute leukemia and maturer granulocytes in certain myeloproliferative and myelodysplastic syndromes. The abnormal granulation in acquired conditions is limited to a few cells as opposed to generalized involvement of all white blood cells and even megakaryocytes in Chediak-Higashi syndrome.

[CHEDIAK-HIGASHI SYNDROME]. Abnormalities of granulation are also seen in cytotoxic T-cells as seen in this lymphocyte with a single large azurophilic granule. This results in cellular immunodeficiency in addition to heightened susceptibility to bacterial infections. With progressive immunodeficiency these patients develop diffuse lymphoid and histiocytic proliferations involving lymph nodes, spleen, bone marrow, liver, and other organs. This usually indicates a terminal stage in the disease and most patients die at around 10 years of age.