 Improvements in isolation techniques and immunosuppressive regimens ushered in the first human islet transplantation clinical trials in the mid-1980s.The first successful trial of human islet allotransplantation resulting in long-term reversal of diabetes was performed at the University of Pittsburgh in 1990.Yet despite continued procedural improvements, only about 10% of islet recipients in the late 1990s achieved euglycemia (normal blood glucose).