Transplantation is the treatment of choice for most causes of end stage renal disease.(1, 2) However, without some modification of the recipient's immune system all allografts succumb to rejection. To prevent this, patients must take immunosuppressive drugs for life, generally a combination of steroids, a calcineurin inhibitor (CNI), such as cyclosporine or tacrolimus, and an antiproliferative agent (azathioprine, mycophenolate mofetil or sirolimus).(3-6) Induction with a brief course of an anti-T lymphocyte antibody preparation (daclizumab, basiliximab, muromonab, alemtuzumab, polyclonal anti-thymocyte globulin) is also used in approximately 70% of U.S. transplant centers.