Islet and Pancreatic Transplantation — Autoimmunity and Alloimmunity

Given the autoimmune cause of insulin-dependent diabetes mellitus,1 the theoretical barriers to successful pancreatic and islet transplantation are autoimmunity (destruction of beta cells due to recurrent autoimmunity) and alloimmunity (rejection of transplanted tissue from a genetically different person).2 In this issue of the Journal, Tydén and coworkers provide evidence of the selective loss of beta cells in two patients with insulin-dependent diabetes mellitus in whom pancreatic allografts were rejected.3 Selective loss of the insulin-producing beta cells is the hallmark of autoimmune diabetes,4 and the islet cells that produce glucagon, somatostatin, and pancreatic polypeptide are spared. Beta-cell loss in allografts raises . . .