Spontaneous suppressor cell activity in patients with the acquired immune deficiency syndrome and associated conditions.

Patients with the acquired immune deficiency syndrome (AIDS) have depressed cell-mediated immunity partially explained by a depletion of helper-inducer T-lymphocytes. We questioned if the remaining elements of the mononuclear cell (MNC) population also played a part in the immunologic abnormalities noted. We therefore evaluated the ability of MNC populations from homosexuals with AIDS and AIDS-associated conditions to suppress the mitogenic responses of control MNCs in an assay of "spontaneous suppressor" cell activity (SSCA). Asymptomatic homosexuals and homosexuals with chronic lymphadenopathy, Kaposi's sarcoma, or opportunistic infections (OIs) had levels of SSCA equal to or greater than that of control subjects. Levels were significantly higher in patients with lymphadenopathy (p less than or equal to 0.1) and in patients with OI (p less than or equal to 0.05). Although percentages of Ia+ cells were increased in all homosexual groups and highest in patients with OIs (p less than or equal to 0.05), percentages of either monocytes or suppressor/cytotoxic T-lymphocytes, potential mediators of SSCA function, did not correlate with levels of SSCA observed. Therefore, patients with AIDS and AIDS-associated conditions have MNC populations that appear to interact in producing normal or augmented down regulation of residual T-lymphocyte function, even in the face of helper/inducer T-lymphocyte depletion.