Viral infections and cell-mediated immunity in immunodeficient homosexual men with Kaposi's sarcoma treated with human lymphoblastoid interferon.

Herpesviral infections and cellular immunity were studied in 19 patients with acquired immunodeficiency syndrome who were treated with human lymphoblastoid interferon for Kaposi's sarcoma. Before treatment, cytomegalovirus (CMV) and Epstein-Barr virus were isolated from 18 of 19 patients and 13 of 14 patients, respectively. Serum levels of interferon were measurable in all cases. Concanavalin A induced lymphocyte proliferation normally in 16 of 18 patients, but CMV induced proliferation in only nine of 18 patients. Natural killer cell activity was normal in 12 of 19 patients and was augmented in vitro by interferon in six of 19 subjects. CMV-specific HLA-restricted cytotoxic T cell activity was found in only two of 15 cases. With therapy, serum levels of interferon increased in 15 of 18 patients. There were two partial tumor remissions but no improvements in viral infections. Natural killer cell activity was decreased in 11 of 14 cases, and in vitro augmentation by interferon was absent in all five previous responders. CMV-specific T cell activity did not improve, but HLA-unrestricted cytotoxicity was increased in four of eight cases.