Immunoregulation in Infection Caused by Mycobacterium tuberculosis: The Presence of Suppressor Monocytes and the Alteration of Subpopulations of T Lymphocytes

Abstract

This study was designed to characterize qualitative and quantitative alterations, occurring before and during chemotherapy, in the mononuclear cells of patients with infections caused by Mycobocterium tuberculosis. A hemolytic plaque-forming (PFC) assay indicated that the production of antibody to sheep red blood cells by pokeweed mitogen (PWM)-stimulated lymphocytes was suppressed in treated and untreated patients as compared with that in normal adult donors (P < 0.001). The removal of adherent cells from the suspensions of mononuclear cells significantly enhanced the responses to the PFC assay for both the untreated (P < 0.01) and treated (P < 0.05) patients. Mononuclear cells from patients with tuberculosis, however, did not suppress the PFC responses of allogeneic normal mononuclear cells (P > 0.02). Thymus-derived (T) lymphocytes were proportionally reduced in untreated subjects (P < 0.001) but returned to normal levels after four to six weeks of therapy (P> 0.2). Both groups of patients had a consistent reduction in the absolute number of circulating T cells. However, untreated patients had a relative increase in the percentage of T G cells (the subpopulation of T cells with receptors for the Fe portion of IgG) (P < 0.001) and a concomitant decrease in T M cells (the subpopulation with Fe receptors for IgM) (P < 0.05). These alterations in the subsets of T cells were reversed after four to six weeks of therapy.