Patterns of interferon-gamma production by peripheral blood mononuclear cells from patients with human immunodeficiency virus infection.

A number of immune parameters have been described as impaired in AIDS patients. The patterns of interferon-gamma (IFN-gamma) production by peripheral blood mononuclear cells (PBMC) from AIDS-related complex (ARC) and AIDS patients in response to specific and nonspecific mitogens and their relationship to proliferative responses, interaction with exogenous interleukin 2 (IL-2), and absolute CD4 cell counts were studied. The PBMC were exposed to phytohemagglutinin (PHA) or cytomegalovirus (CMV) antigen (Ag) and/or 10 units of IL-2. At selected times, culture supernatants were tested for IFN-gamma production by radioimmunoassay and at identical times proliferative responses were determined by [3H]thymidine uptake. IFN-gamma production in response to PHA or CMV Ag was inhibited significantly and appeared dependent on absolute CD4 cell counts. Proliferative responses were also similarly decreased. While IFN-gamma production to PHA was severely inhibited in PBMC only from patients with less than 100 CD4 cells/mm3, equivalent inhibition in response to CMV Ag was observed only in those with CD4 counts less than 600/mm3. IL-2 enhanced the PHA and CMV Ag-induced IFN production significantly by 2.8- and 5.3-fold respectively. Therefore, the administration of IL-2 might improve certain cell-mediated immune responses.