Dysregulation of the polymorphonuclear leukocyte - Candida spp, interaction in HIV-positive patients

Objective: In HIV-infected patients there is an increased frequency of fungal infections. Dysregulation of the response of phagocytic cells to fungal pathogens may be involved. Design: Phagocytosis of Candida spp., consecutive intracellular production of reactive oxygen species, and candicidal activity were analysed in polymorphonuclear leukocytes (PML) from HIV-1-infected patients, who were at stage C3 of the 1993 revised Centers for Disease Control and Prevention classification system, by means of flow cytometry. Methods: Phagocytic ability was assessed by measuring uptake of fluorescein isothiocyanate-labelled Candida albicans, C. krusei and C. glabrata. Reactive oxygen intermediate production was estimated by the quantity of dihydrorhodamine-123 converted to rhodamine-123 intracellularly. The candicidal effect was assessed by the propidium iodide uptake of killed yeast cells. Results: As compared to PML of healthy, HIV-negative controls, PML of AIDS patients exhibited an increased phagocytic activity and a similar ability to generate reactive oxygen products. In contrast, PML of AIDS patients displayed a decreased candicidal activity (P<0.05 compared to controls). Conclusion: These results suggest that in patients with advanced HIV-1 infection the impairment of non-oxidative killing mechanisms of phagocytic cells may contribute to the high incidence of fungal infections.