B‐Cell Function and Islet Cell and Other Organ‐Specific Autoantibodies in Relatives to Insulin‐Dependent Diabetic Patients

The pancreatic B-cell function (glucose tolerance, C-peptide release) and organ-specific autoantibodies, including islet cell cytoplasmic and cell surface (mouse), were studied in 45 first-degree relatives of patients with insulin-dependent diabetes mellitus diagnosed before the age of 30 years. Com- pared to 107 healthy persons without any family history of either insulin-dependent or non-insulin- dependent diabetes mellitus, the prevalence of auto- antibodies was increased among the relatives. The prevalence of islet cell antibodies did not differ be- tween relatives and controls and none of the indi- viduals had complement-fixing islet cell antibodies. There was no difference in glucose tolerance or C- peptide release between relatives and controls, whether they had autoantibodies or not. At a three- year follow-up, none of the individuals had developed insulin-dependent diabetes.