ObjectiveTo study the influence of HIV infection on phagocyte function. To date, the results of phagocyte function studies in HIV-infected patients have been contradictory. This is the first longitudinal study of these functions in HIV infection.DesignWe followed 50 individuals with HIV infection for 2–51 months (mean, 28 months) and examined polymorphonuclear leukocyte (PMNL) and monocyte functions at intervals of 0.5–1 years.MethodsPMNL random migration and chemotaxis were assessed using an under-agarose method, and PMNL and monocyte oxidative metabolism by chemiluminescence production during phagocytosis of opsonized zymosan.ResultsPMNL random migration and chemotaxis were impaired at entry into the study by 15 and 19%, respectively. After 3 years the reduction was 35 and 32%, respectively. The mean chemiluminescence production by PMNL was reduced by 6% at entry into the study. After 4 years a decrease of 18% was observed. The decrease in PMNL function was most marked in patients with lymphadenopathy syndrome or AIDS. No significant change in monocyte chemiluminescence production was detected at any time during the study.ConclusionsA distinct and progressive decrease of PMNL function occurs during HIV infection. This may contribute to increased susceptibility to opportunistic infections in HIV-infected patients. For monocytes, chemiluminescence production is not influenced by HIV infection.