Congenital Aplasia of the Thymus Gland (DiGeorge's Syndrome)

Abstract

Two infants with congenital aplasia of the thymus were found to have normal polymorphonuclear-leukocyte function, immunoglobulins and antibody formation. Delayed hypersensitivity, allograft rejection and in vitro lymphocyte responses to phytohemagglutinin were impaired. Lymphoid tissue of these two patients and postmortem material from a third revealed a moderate deficiency of lymphocytes in the deep cortical regions of the lymph nodes and periarteriolar sheaths of spleen but normal cortical germinal-center activity and plasma cells. Thus, in thymic aplasia humoral immunity is normal, but cellular immunity is deficient, findings precisely the reverse of what is found in congenital agammaglobulinemia. The dichotomy found between the two types of immunity is consistent with experimental studies showing a separable cellular origin for humoral and cellular immunity.