Immunoregulation in infection caused by mycobacterium tuberculosis: The presence of suppressor monocytes and the alteration of subpopulations of t lymphocytes

This study was designed to charaterize qualitative and quantitative alterations, occurring before and during chemoterapy, in the mononuclear cells of patients with infections caused by Mycobacterium tuberculosis. A hemolytic plaque-forming (PFC) assay indicted 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 4 to 6 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 TG T(G) (the subpopulation of T cells with receptors for the Fc portion of IgG) (P<0.001) and a concomitant decrese in T(N) cells (the subpopulation with Fc receptors for IgM) (P <0.05). These alterations in the subsets of T cells were reversed after 4 to 6 weeks of therapy.