Additional Study Information: This is a 60-month adaptive to evaluate three siplizumab-based treatment regimens in kidney transplant recipients. The purpose of this research study is to see if the anti-rejection medications that patients normally take after transplant can be reduced or stopped completely by using several medications including the investigational drug siplizumab in the days before the kidney transplant, that may induce immune tolerance by combining a bone marrow cell infusion with the kidney transplant from the same person (the donor). Approximately 18 donor/recipient pairs will be enrolled. Donor participation will last for 9 weeks, while recipient participation will last until 5 years post-transplant. A few days before the transplant, the recipient will start to receive the study drugs. The recipient will then receive a kidney transplant and the bone marrow cell infusion from their donor. After the transplant, the recipient will continue to receive the study drugs for a few more doses and then the usual anti-rejection medication will be started. After several months, as long as the recipient's health is good and kidney is functioning well, the anti-rejection medication will be slowly stopped. Recipients will then return to the study site every 3 months for the next two years following transplant for overall health and research laboratory assessments and so the study doctor can continue to monitor the condition of the new kidney. If you have any questions regarding this study, please contact the Transplant Clinical Research Center (TCRC).