The rejection of islets of Langerhans following intrahepatic transplantation in the rat.

Pancreatic acinar tissue and islets of Langerhans have been isolated using a collagenase technique from Agus rats and transplanted separately into the liver of diabetic and nondiabetic isogeneic Agus and allogenic PVG/C rats. Livers were removed on days 1, 2, 4, 7 and 14 and examined histologically. Transplanted isogeneic islets showed no evidence of cellular infiltration and the beta cells appeared fully granulated. Transplanted allogeneic islets in non-diabetic recipients were surrounded by a mononuclear cellular infiltrate on day 2 and this became maximal by day 4. Although initially fully granulated, beta cells became degranulated on day 7 and by day 14 only small fragments of islet tissue remained. In allogeneic diabetic recipients the cellular infiltrate appeared less dense; beta cells appeared incompletely granulated from days 1 to 4 and a transient fatty degeneration occurred in the hepatic parenchuma around islets.