MONOCYTE DYSFUNCTION IN PATIENTS WITH ACQUIRED-IMMUNODEFICIENCY-SYNDROME (AIDS) VERSUS CRYPTOCOCCUS-NEOFORMANS

In the present study we investigated the response of monocytes from AI DS patients, susceptible to cryptococcosis (<200 CD4 cells/mu l), agai nst Cryptococcus neoformans. Different patterns of response were obser ved in these cells compared to cells from healthy donors. In particula r, fungicidal activity versus this fungus was impaired; this phenomeno n could be due to the difficulty of monocytes to internalize C. neofor mans in the presence of an intact complement system. Impairment of com plement receptor type 3 and direct involvement of this receptor in pha gocytosis of C. neoformans were found in monocytes from AIDS patients, which mag account for the difficulty in phagocytosis of the fungus. A lso, superoxide anion production was dramatically reduced in monocytes from AIDS patients, An increase of spontaneous tumor necrosis factor (TNF) production was evidenced after in vitro addition of C. neoforman s. However, this did not activate the antifungal capacity of monocytes from AIDS patients. Moreover, cryptococcus-laden monocytes from AIDS patients were able to induce only a weak response of autologous T-lymp hocytes. Hence, monocyte dysfunction could play a part in the progress ion of cryptococcosis in AIDS.