Selective Defects in Cytomegalovirus- and Mitogen-Induced Lymphocyte Proliferation and Interferon Release in Patients with Acquired Immunodeficiency Syndrome

To examine the defect in cellular immunity in patients with acquired immunodeficiency syndrome (AIDS), we studied in vitro lymphocyte proliferation and interferon (IFN) release in response to cytomegalovirus (CMV) antigen and Concanavalin A mitogen in 40 homosexual men with AIDS, 10 homosexual men with chronic lymphadenopathy syndrome, 7 healthy homosexual men, and 18 healthy heterosexual subjects of either sex. CMV serology by an enzyme-linked immunosorbent assay and viral cultures for CMV were performed. Lymphocytes of patients with AIDS showed impaired CMV-specific release of IFN but normal mitogen-induced IFN release. The defect was not attributable to CMV infection per se. Cell proliferation in response to both CMV antigen and mitogen was impaired in patients with AIDS who had opportunistic infections. The defect could not be attributed to CMV viremia. We concluded that impaired release of IFN in response to a viral antigen is characteristic of lymphocytes in patients with AIDS and that this defect is distinct from a defect in mitogenic responsiveness, which coexists predominantly in patients with opportunistic infections.