Combined Kidney and Hematopoietic Stem Cell Transplantation for Tolerance Induction

Combined transplantation of kidney and bone marrow between HLA-matched sibling donor-recipient pairs to induce immune tolerance in order to enable complete discontinuation of immunosuppressive therapy without kidney rejection. Hematopoietic stem cells are collected from the donor 4 to 8 weeks before kidney transplantation, CD34 cells are enriched by positive selection and cryopreserved. The day after kidney transplantation the recipient starts conditioning therapy with thymoglobuline, total lymphoid irradiation, steroids, tacrolimus and mycophenolate mofetil. Eleven days after kidney transplantation the stem cell graft is thawed and infused to the recipient. If mixed donor chimerism is successfully maintained more than 6 months without rejection, then immunosuppression may be tapered off until complete discontinuation.