Increased Phagocytosis and Generation of Reactive Oxygen Products by Neutrophils and Monocytes of Men with Stage 1 Human Immunodeficiency Virus Infection

Flow cytometry was used to study phagocytic function and release of reactive oxygen products following phagocytosis by neutrophils (PMNL) and monocytes of heparinized whole blood from stage 1 human immunodeficiency virus type 1 (HIV-1)-infected men. Phagocytic capacity was assessed by measuring uptake of Texas red-labeled bacteria. Reactive oxygen generation after phagocytosis was estimated by the quantity of dichlorofluorescein diacetate converted to dichlorofluorescein intracellularly. Compared with results in samples from age- and sex-matched controls, PMNL and monocytes from HIV-1-infected patients exhibited a significantly increased capacity to phagocytose Staphylococcus aureus and Escherichia coli and generate reactive oxygen products. These results are consistent with the hypothesis that stimuli associated with early HIV-1 infection enhance the nonspecific response of phagocytic cells to potential bacterial pathogens.