Immune reactions in patients with type I and with type II diabetes mellitus.

Since several data refer to the role of immune processes in the pathogenesis of diabetes mellitus, this study was performed to compare aspecific and specific immune reactions in type I- and in type II diabetic patients over a six month period. The percentage and the absolute number of SRBC-rosette forming active E(A), of theophylline-resistant E(Thr) and of ORCB-rosette forming T(M)-cell subsets proved to be elevated in newly diagnosed type I but reduced in type II diabetic patients. Also an elevated percentage of HLA-DR positive, activated T cells was found in the majority of recent-onset type I diabetics. In the presence of human pancreas extract, a significant inhibition of leucocyte migration, a pronounced and specific cytotoxic capacity of all lymphocyte subsets (especially of the T(G)-cells), and elevated antibody titers (passive haemagglutination, indirect immunofluorescence) were observed in almost all type I diabetics, but only in a few cases of type II patients. After six months, the frequency both of the aspecific and of the specific immune parameters was decreased in type I diabetics, but no changes were observed in the type II diabetics with a previously positive test. The latter patients required insulin therapy at the time of the second investigation. The leucocyte migration inhibition test and the lymphocyte-mediated cytotoxicity are suitable for studying in-vitro-sensitization against pancreatic tissue and they might predict later insulin-dependency in type II diabetic patients.