Islet transplantation in the twenty-first century.

Isolated islet transplantation is poised for clinical application to treat insulin-dependent diabetes. Unlike exogenous insulin therapy, islet transplantation has promise for preventing and/or reversing the dismal secondary complications of diabetes. Islet transplants are arguably the most unique type of allografts, and we discuss their properties, limitations, and potential in this overview. The induction of immunologic tolerance to allow islet grafts to endure and prevail, without the hardship of chronic immunosuppressive therapy, is a major goal in this field. In this context, we discuss our successful results in preclinical models of primate allogeneic and xenogeneic islet graft tolerance.