Autoantibodies against human insulin.

Sera from 680 non-diabetic subjects with suspected autoimmune disease were screened for 13 different antibodies. Of the 582 sera found to contain these antibodies, nine bound insulin in an IgG specific enzyme linked immunosorbent assay (micro ELISA). Four of the sera bound human, porcine, and bovine insulins and five bound exclusively human insulin. "Cold" human, porcine, and bovine insulins each displaced, in a dose dependent manner, the four sera which bound all three insulins, but only human insulin displaced the remaining five, porcine and bovine insulins having little or no effect in concentrations up to 1000 U/1. These observations point to the existence of autoantibodies specifically against human insulin in some subjects with established autoimmunity.