Dr. Andrew Posselt is a transplant surgeon at UCSF where he specializes in adult and pediatric kidney, liver and pancreas transplants. He heads the pancreatic islet transplantation program and is the co-director of the UCSF Bariatric Surgery Center. In addition to caring for patients, Posselt is involved in research on islet transplants, the mechanisms behind the tolerance or rejection of transplanted tissue and the metabolic and biochemical consequences of bariatric surgery. Posselt joined UCSF in 2003.