Interleukin-2 enhances the depressed natural killer and cytomegalovirus-specific cytotoxic activities of lymphocytes from patients with the acquired immune deficiency syndrome.

The recently described acquired immune deficiency syndrome (AIDS) is characterized by the occurrence of severe opportunistic infections and an aggressive form of Kaposi's sarcoma. A variety of profound defects in cell-mediated immunity have been reported in association with the AIDS, including deficiencies in natural killer (NK) cell activity and cytomegalovirus (CMV)-specific cytotoxicity. In the present study, the in vitro effects of interleukin-2 (IL-2) and interferon beta (IFN Beta) on these abnormalities were examined to assess the potential use of these lymphokines in the immunotherapeutic treatment of this syndrome. The peripheral blood lymphocytes (PBL) from six male homosexuals with AIDS and an active CMV infection exhibited markedly depressed NK cell and CMV-specific cytotoxic lymphocyte responses compared with uninfected, heterosexual control subjects. Incubation of PBL with IFN Beta enhanced the NK cell activity and the CMV-specific cytotoxicity of only one of six and neither of two AIDS patients, respectively, while enhancing the NK cell activity of all six control subjects. In contrast, IL-2 dramatically enhanced both the NK cell and the CMV-specific cytotoxic lymphocyte activities of all of the patients. These results indicate that IL-2 can substantially potentiate the depressed cytotoxic effector functions of PBL from AIDS patients, while IFN Beta has little effect.