Occurrence of antibodies to insulin in patients with autoimmune thyroid disease.

Insulin autoantibodies (IAA) in patients with autoimmune thyroid disease (n = 97) were determined by a displacement-based ELISA technique. There were 78 patients with Graves' disease and 19 with autoimmune thyroiditis. The assay precision unit, standard deviation score, was used to assess the presence of IAA. It was determined that 7.2% were assessed to be IAA-positive. None of the patients had islet cell antibodies. Thyrotrophin receptor antibodies (TRAb) were only present in patients with Graves' disease. The mean TRAb levels in patients who relapsed (95.0 +/- 141 IU/l, n = 36) were significantly higher (p = 0.042) than those newly diagnosed for Graves' disease (38.3 +/- 36 IU/l, n = 28). Insulin autoantibody levels in these two subgroups were not different from each other. In addition, TRAb levels were not related to IAA levels. A retrospective study of 12 patients on carbimazole treatment indicated that modulation of TRAb levels had no concomitant effect on the development of IAA.