My major research interest concerns identifying and studying factors that affect the success of kidney transplants. We have been fortunate to have access to information we've collected about more than 100,000 recipients, their donors, and transplants from 150 international transplant centers that participate in the UCLA International Kidney Registry and from more than 250 United States transplant centers who submit data on all US kidney transplants to the United Network for Organ Sharing Registry. We have used these resources to study the results of transplantation and to identify strategies to improve transplant success rates. Our studies of Registry data have resulted in more than 180 scientific publications, some of which have had a profound influence on the practice of transplantation. As graft survival rates have improved over the years, our primary research interests in the role of HLA antigens and the immune response in transplantation have broadened to include non-immune factors that also affect the outcome of transplants. We have identified events surrounding the donor's death (the donor's age and cause of death, hypertension, treatments administered prior to death) and events occurring at the time of transplant (ischemic injury, antibody mediated injury, rejections), which affect the early graft function and immunogenicity of grafted kidneys. We are studying the effect of injuries to the graft that occur before or at the time of transplant on subsequent delayed graft function, early acute rejection and accelerated long-term graft failure.