Diabetes mellitus in the BB/W rat. Insulitis in pancreatic islet grafts after transplantation in diabetic recipients.

Spontaneous diabetes mellitus in the BioBreeding/Worcester (BB/W) rat is preceded by lymphocytic insulitis which destroys pancreatic beta cells. Cultured major histocompatibility complex identical pancreatic islets and adrenal cortex derived from diabetes-resistant BB/W donors were transplanted into diabetic recipients with hyperglycemia of variable duration. Islet grafts were the targets of BB/W immune attack and revealed lymphocytic insulitis after transplantation into diabetic recipients even in the absence of insulitis within endogenous pancreatic islets. These findings suggest that the BB/W immune attack on pancreatic beta cells can recur in islet grafts long after the onset of the diabetic syndrome.