Defect of cellular suppressor function in the pathogenesis of type I diabetes mellitus

In 29 out of 30 type I diabetic patients the peripheral blood lymphocytes induced an insulin release from isolated rat islets which was regarded as a cytotoxic effect, i.e. a model of beta cell destruction in diabetes mellitus. In 11 out of 12 cases, this effect was inhibited by the in-vitro addition of lymphocytes from healthy probands. Thus the activation of cytotoxic T-cells demonstrated by this observation might be the consequence of a defect in suppressor cell function. Consequently, the transfusion in vivo of lymphocytes from healthy probands strongly reduced the cytotoxic reaction of the lymphocytes from newly diagnosed diabetic recipients in vitro.