Mycobacteremia in acquired immune deficiency syndrome. Rapid diagnosis based on inclusions in the peripheral blood smear

In 16 cases of human immunodeficiency virus-associated Mycobacterium avium-intracellulare complex (MAC) infection, 7 were diagnosed after finding intracytoplasmic negatively staining linear inclusions within histiocytes using Romanowsky-stained bone marrow aspirate smears. Four patients had inclusions within monocytes and neutrophils in the peripheral blood smear. The authors believe these cases represent the first reported examples of MAC inclusions observed within leukocytes in Wright's-stained peripheral blood smears. Inclusions usually were found in the setting of prominent toxic changes in leukocytes such as large Dohle bodies, marked granulation, and vacuolation. These inclusions are characteristic of mycobacteria and can be confirmed by acid fast stains and mycobacteriologic culture. The authors present the clinical and laboratory setting in which identification of inclusions in peripheral blood smears may be a rapid, minimally invasive, and cost-effective method of diagnosing mycobacterial infection.