Apoptosis is a phenomenon of physiological cell death in which each step is regulated, similar to the process of mitosis. We observed apoptosis in leukocytes during the review of peripheral blood smears. This study was undertaken to evaluate the morphologic features of apoptotic leukocytes in peripheral blood smears and to ascertain their clinical significance.
Sixty cases (23 males and 37 females, aged newborn to 92 years) exhibiting apoptotic leukocytes in peripheral blood smears were studied. Medical records for each case were reviewed, and patients were categorized according to their clinical diagnoses.
Neutrophils were the most common apoptotic leukocytes identified (85%), followed by lymphocytes (18%) and eosinophils (2%). The diagnosis most frequently associated with the presence of apoptotic leukocytes was infection (55%). Apoptosis in lymphocytes was comparatively less common, but when present, the most common associations were diabetes mellitus, glucocorticoid administration, and neoplastic diseases.
Our findings suggest that the presence of apoptotic leukocytes in peripheral blood smears may help in the differential diagnosis and may be related to the severity of disease. We recommend further evaluation using additional special techniques for detecting apoptotic leukocytes.