Complete withdrawal of immunosuppression in kidney allograft recipients - A prospective study in rhesus monkeys

Background. We previously reported the successful withdrawal of immunosuppression in kidney-allografted rhesus monkeys. Recipients had received pretransplant blood transfusions and cyclosporine (CsA) immunosuppression for 6 to 12 months. One animal is still alive at more than 15 years after transplantation. Our hypothesis was that the sharing of a single DR antigen between blood donor and recipient, and the sharing of the same DR antigen with the kidney donor,may be beneficial to allograft survival. We now report on the results from a prospective study. Methods. The animals received three pretransplant blood transfusions hom a single donor sharing one DR antigen with the recipient. Subsequently, a life-supporting kidney from a donor sharing the same DR antigen was transplanted. CsA was given for at least 6 months after transplantation. Results. Two animals rejected their graft at 5-8 weeks after cessation of CsA treatment. One animal is still alive at 700 days after transplantation. This animal showed MLR nonreactivity to its kidney donor, similar to the animal at more than 15 years after transplantation. Conclusion. These results demonstrate that withdrawal of immunosuppression may be a realistic option in kidney graft patients under careful immunological monitoring of donor-specific immunity.