Tolerance and Chimerism after Renal and Hematopoietic-Cell Transplantation

A patient received a kidney graft from his HLA-identical brother, followed by an infusion of CD34+ hematopoietic stem cells from the same donor. An apparent state of immunologic tolerance to the kidney allograft developed, allowing withdrawal of all immunosuppressive therapy within 6 months. A patient received a kidney graft from his HLA-identical brother, followed by an infusion of CD34+ hematopoietic stem cells from the same donor. Immunologic tolerance to the kidney allograft developed, allowing withdrawal of all immunosuppressive therapy within 6 months. Immune tolerance of organ transplants has been induced in laboratory animals when persistent mixed blood and immune-cell chimerism has been achieved by infusing hematopoietic cells from the organ donor before or after transplantation of the organ. 1 – 3 The continued presence of the organ donor's immune cells in the recipient's thymus and peripheral lymphoid tissue promotes and maintains immune tolerance by eliminating T-cell clones that can react to alloantigens of the graft. 1 – 3 We have attempted to achieve persistent mixed chimerism and tolerance in humans after transplantation of combined HLA-matched kidney and hematopoietic cells, using a low-intensity conditioning regimen of total . . .