Successful intra-splenic transplantation of syngeneic and allogeneic isolated pancreatic islets.

Adult rat islets harvested by the collagenase digestion/Ficoll separation technique were injected into the splenic pulp in 9 syngeneic (Lewis-leads to Lewis and WaG leads to WaG) and 13 allogeneic [(DA X Lewis) F1 leads to Lewis] experiments. Normal serum glucose levels and 24 hour urine volumes were restored in all 9 syngeneic recipients and in 11 out of the 13 allogeneic recipients in a mean of 3.3 days. Splenectomy performed on 3 of the 9 syngeneic recipients 110-178 days after transplantation resulted in a prompt return to the diabetic state. In all the remaining syngeneic recipients, normal values have persisted for the current period of observation of 6 months. In 5 untreated allogeneic recipients, rejection occurred in a mean of 5.2 days. The administration of a short course of ALS (1 ml I.P. days-1, 1, 3 and 5) to the remaining 6 animals greatly prolonged graft survival with all animals remaining normoglycaemic for at lest 4 weeks. These results were not significantly different from those recorded in comparable groups of intra-portal allogeneic islet recipients.