Influence of postdiabetic onset time and immunosuppressive treatment on islet grafts in the spontaneous diabetic BB/W rat.

1000 islets from one donor, isolated with a modified neutral red method, were intraportally transplanted from BB/Wistar or Lewis (RT1) donors to short- and long-term diabetic BB/Wistar recipients. Recipients received immunosuppression with cyclosporine i.m.--either postoperative 4 X 25 mg/kg body weight or pre- and postoperative 3 X 10 mg and 4 X 25 mg/kg body weight. Graft survival in short-term diabetic recipients was significantly shorter than in long-term diabetics, whether they were immunosuppressed or not. Especially in recent onset recipients, the additional preoperative immunosuppression with cyclosporine provided longer graft survival than postoperative cyclosporine alone. Histological examinations of islet grafts showed eosinophilic cells in all transplanted islets, in both functioning and clinically rejected grafts of allogenic and "pseudoisogenic" transplanted recipients. a coincidence of eosinophilic cells with the reenactment of the original autoimmune disease in islet grafts seems possible.