Imbalances in T cell subpopulations associated with immunodeficiency and autoimmune syndromes

Abstract

Abnormal proportions of the distinct T cell subpopulations binding the Fc portion of IgM (T_·M) cells and those bearing receptors for the Fc portion of IgG (T_·M) cells, were observed in blood samples from patients who had congenital or acquired abnormalities of the thymus, severe combined immunodeficiency, or an unexplained primary deficiency in cell-mediated immunity; most had too few circulating T_·M cells and often an overabundance of T_·G cells. In an in vitro evaluation of lymphocytes from one of three thymoma patients with an elevated T_·G subpopulation, removal of T_·G cells abrogated the suppression of T_·M cell help of B cell differentiation induced by pokeweed mitogen. A spectrum of patients with sex-linked infantile agammaglobulinemia, variable hypogammaglobulinemia, and selective IgA deficiency, and a few patients with autoimmune syndromes infrequently had distorted representation of these T cell subpopulations in the circulation. This suggests that B cell dysfunction in many of these patients is not merely due t o numerical excesses or insufficiencies of helper or suppressor T cells.