Immunoreactivity to a 64,000 Mr human islet cell antigen in sera from insulin-dependent diabetes mellitus patients and individuals with abnormal glucose tolerance.

Autoantibodies in sera from newly diagnosed insulin-dependent diabetes mellitus (IDDM) patients recognize a 64,000 Mr human islet cell antigen. The incidence of these antibodies was 86% in 28 insulin-dependent diabetes mellitus patients, 100% in seven first-degree relatives with abnormal glucose tolerance, 6% in 34 healthy individuals, 17% in 29 patients with Hashimoto's or Graves' disease, and 0% in five systemic lupus erythematosis patients. It is suggested that the 64,000 Mr human islet cell protein is the major target antigen of islet cell autoantibodies in insulin-dependent diabetes mellitus.