Mechanisms responsible for defective human T lymphocyte sheep erythrocyte rosette function associated with hepatitis B virus infections

Abstract

The expression of selected lymphocyte surface membrane markers was evaluated in 37 patients with acute viral hepatitis B, 10 of whom were studied serially through the resolving and convalescent phases of disease. Bone marrow derived (B) lymphocytes were identified by reference to surface immunoglobulin, whereas normal thymus derived (T) lymphocytes were assayed by their capacity to form spontaneous nonimmune rosettes with sheep erythrocytes (E rosettes, ER). During the acute and resolving phases of viral hepatitis B, the relative and absolute number of ER positive lymphocytes was significantly reduced, whereas the number of surface immunoglobulin positive lymphocytes and the absolute lymphocyte count remained normal. This resulted in the appearance of a third population of cells, deficient in respect to both surface immunoglobulin and ER markers. Such cells accounted for nearly 25% of peripheral blood lymphocytes, approximately 5 x 105 ml blood. Depression of the number of ER positive lymphocytes occurred at least once during the course of disease in every patient studied serially, and was observed in 55 of 67 individual assays of the 37 cases of acute viral hepatitis B. Lymphocytes from some patients reacquired ER function when cultured in fetal calf serum but not in the presence of autologous serum. Such autologous serum was capable of suppressing ER function of lymphocytes from normal donors. The extrinsic suppression of ER function by a serum factor (designated as the Rosette Inhibitory Factor), was found to be time dependent, characterized by a 4 h latent period and requiring approximately 18 h for maximum attenuation of ER function. The Serum Rosette Inhibitory Factor was: heat and freeze thaw stable, nondialyzable, physically separable from hepatitis B surface antigen, not a lymphocytotoxic antibody, and had the buoyant density of a lipoprotein. This extrinsic mechanism was observed in 41.8% of patients with reduced numbers of ER positive lymphocytes.