IN-VITRO PRODUCTION OF TYPE-1 AND TYPE-2 CYTOKINES BY PERIPHERAL-BLOOD MONONUCLEAR-CELLS FROM HIGH-RISK HIV-NEGATIVE INTRAVENOUS-DRUG-USERS

Objective: To study type 1 and type 2 cytokine patterns in HIV-negativ e high-risk intravenous drug users (IVDU). Design: We investigated int erleukin (IL)-2, interferon (IFN)-gamma, IL-4, IL-6 and IL-10 producti on by phytohaemagglutinin (PHA)-stimulated and unstimulated peripheral blood mononuclear cell (PBMC) cultures from HIV-negative high-risk IV DU, HIV-negative controls and HIV-positive subjects. Methods: Cytokine production was measured in supernatants using enzyme-linked immunosor bent assay (ELISA) in 10 HIV-negative high-risk IVDU, 25 HIV-negative controls, and 12 HIV-positive IVDU. We also determined spontaneous in vitro immunoglobulin (Ig) G and IgM production. Results: HIV-negative high-risk IVDU showed increased IFN-gamma and decreased IL-4, IL-10 an d IL-2, although the latter was not significant compared with HIV-nega tive controls. Further, HIV-negative high-risk IVDU had reduced IgG pr oduction and impaired IgM-lgG switch. Conclusions: The reduced IL-2 an d IL-4 production suggest an impaired CD4+ T-cell function in HIV-nega tive high-risk IVDU. The increased IFN gamma production along with the decreased type 2 cytokine profile is consistent with the hypothesis t hat protective immunity against HIV may reside in type 1 responses and cell-mediated immunity.