We analyzed the in vitro synthesis and release of PGE2, IL-1 beta, and TNF-alpha by peripheral blood monocytes from HIV-infected injection drug users at the early clinical stages of HIV infection. We investigated whether there is a concomitant altered production of PGE2 and proinflammatory cytokines by HIV-positive monocytes. We also evaluated T-cell subsets and lymphocyte transformation response to pokeweed mitogen (PWM) in HIV-positive patients and healthy controls. PGE2 and IL-1 beta levels in supernatants from monocyte cultures were determined by radioimmunoassay (RIA), and TNF-alpha by enzyme immunoassay (EIA). Monocytes from asymptomatic HIV-positive individuals produced spontaneous and significantly increased quantities of PGE2, IL-1 beta, and TNF-alpha. Concomitant increased production of PGE2 and IL-1 beta by monocytes from HIV-positive asymptomatic patients was significantly associated with low CD4+ T-cell numbers (< 500 cells/mm3). We also found a strong association between spontaneous and concomitantly increased production of PGE2 and cytokines by monocytes from asymptomatic HIV-positive individuals and a low lymphocyte transformation response to PWM. Further studies are necessary to establish whether this altered production of PGE2 and proinflammatory cytokines by monocytes from HIV-positive individuals might play a role in the mechanisms involved in the progressive impairment of cell-mediated immunity in HIV infection.