Blood monocyte and neutrophil functions in the acquired immune deficiency syndrome.

The acquired immune deficiency syndrome (AIDS) is characterized by infections with microorganisms against which phagocytes (especially monocytes/macrophages) play an important role. Therefore, various functions of blood monocytes and neutrophils were tested in 16 patients with AIDS. Neutrophil chemotactic responses towards casein and N-formyl-methionyl-L-leucyl-L-phenylalanine were depressed in patients with a short duration of disease (n = 9), whereas they were normal in those with a longer duration (n = 5), P less than 0.05. Neutrophil superoxide anion release was normal. In contrast, we found no evidence of an altered monocyte activity in the patients, since chemotactic responsiveness, phagocytosis of opsonized Candida albicans, and superoxide anion release were all normal. These findings suggest that the depressed neutrophil chemotaxis may play an important role in the high incidence of opportunistic infections in AIDS. Furthermore, it appears that in AIDS the immune deficiency does not extend to peripheral blood monocytes, but it does not exclude the possibility that the function of tissue macrophages is abnormal.