Islet cell cytoplasmic antibodies in Macaca nigra.

Islet cell antibodies (ICA) have been measured in mature Macaca nigra. Of 30 nondiabetic monkeys, 26 (87%) were ICA-negative; of 43 monkeys with evidence of mild to severe hormonal or glycemic abnormalities, 39 (91%) were ICA-positive. Pancreatic islets were examined from biopsy and autopsy sections to assess cell deterioration and amyloid infiltration. No ICA were found in 13 of 18 (72%) monkeys with no evidence of amyloid, whereas 30 of 35 (86%) monkeys with islet amyloid and concurrent cell deterioration were ICA-positive. Association of ICA with metabolic and islet abnormalities was significant at P less than or equal to 0.001. ICA were specific for the islet cells in pancreatic sections; plasma preincubated with insulin, glucagon, or acetone extracts of tissues retained their ICA-positive reaction. The relationships of ICA in older monkeys to the islet lesion and to metabolic abnormalities could be relevant to similar situations in aging diabetic persons.