Immune complexes in newly diagnosed insulin-dependent (type I) diabetics.

Soluble immune complexes (AgAb) and islet cell antibodies (ICAb) were studied in 110 insulin dependent diabetics (IDD) within a week of diagnosis and in about a third of the patients after 1, 3, 6 and 12 months. AgAb were studied by the solid phase Clq binding test in all the patients and also by the Raji cell radioimmunoassay in 52 sera at diagnosis. Diabetics at diagnosis showed a significantly higher incidence of AgAb in comparison with the control population. AgAb positivity declined with increasing time from diagnosis to reach the normal range within 3 months. Both the Clq and the Raji methods revealed a significant correlation at diagnosis between the occurrence at AgAb and the presence of ICAb. The possibility exists that AgAb, perhaps comprised of pancreatic antigen and ICAb, may be involved in the pathogenesis of type I diabetes.