End-stage renal disease affects over 500,000 patients each year in the United States. Currently, over 92,000 people wait on the kidney transplant list in the United States alone, where approximately 16,000 transplants occur annually . With such a discrepancy between supply and demand, graft survival is critical. Yet, even with advances in transplantation technique and immunosuppression, year one acute rejection rates remain between 10% and 20% . Acute rejection begins subclinically and progression may lead to irreversible organ damage or graft loss.