Antibody to cultured human insulinoma cells in insulin-dependent diabetes.

Circulating antibodies to live tissue-cultured human-insulinoma cells were identified in 34 out of 39 insulin-dependent diabetic patients by an indirect immunofluorescent technique. The antibodies were unrelated to insulin therapy since 8 of 9 sera obtained before insulin-replacement treatment were antibody positive and the test results were not influenced by prior addition of porcine insulin to sera. The antibodies were of the IgM and IgG classes. The findings suggest that autoimmune mechanisms are important in the pathogenesis of most cases of insulin-requiring diabetes.