Effect of interferon therapy on circulating lymphocytes in humans

The effect of interferon treatment on both lymphocyte subpopulation numbers and function was studied in two groups of patients who were being treated systemically with 0.5 to 1.0 x 10(7) units of human leukocyte-derived interferon (HulFN-alpha) daily. Patients with nodular lymphocytic, poorly differentiated non-Hodgkin's lymphoma (NLPD) were given interferon for 30 days and those with chronic hepatitis B infection were treated in cycles for 4 to 7 days. In both patient groups, B lymphocytes numbers were reduced during treatment, but T lymphocyte numbers were unaffected. T lymphocyte responses, measured by blast transformation to herpesvirus antigens were generally low before treatment in NLPD patients. The responses were restored after termination of therapy. In two NLPD patients given two courses of treatment separated by a 3 month interval, the restored T lymphocyte responses were inhibited during the second course of treatment. In patients with chronic hepatitis B virus infection, lymphocyte blast transformation to the viral antigens were also depressed during treatment compared to pretreatment responses. Changes in lymphocyte responses to phytohemagglutinin and pokeweed mitogen were not observed in either patient group.