Transplanting the Untransplantable

With implementation of the Kidney Allocation System, the growth of kidney paired donation programs, and advances in desensitization and immunosuppression, the outlook for “untransplantable” kidney transplantation candidates has never been more promising. The Kidney Allocation System prioritized compatible matches for candidates with calculated panel-reactive antibody levels of 98%, 99%, or 100% and broadened allocation of non-A1 and non–A1-B subgroup kidneys to blood group type B candidates. Concurrently, the growth of kidney paired donation programs and use of incompatible transplantation as part of kidney paired donation to achieve “more compatible” kidney transplantation has improved options for candidates with an incompatible living donor. Finally, advances in desensitization and immunosuppression have strengthened the ability to manage donor-specific antibodies and antibody-mediated rejection. Although no patient should be labeled “untransplantable” due to blood group type or donor-specific antibody, all candidates should be provided with individualized and realistic counseling regarding their anticipated wait times for deceased donor or kidney paired donation matching, with early referral to expert centers when needed. In this Perspective, we consider blood group type ABO incompatibility, HLA antigen incompatibility, antibody-mediated rejection, kidney paired donation, and recent developments in incompatible transplantation in more depth and recommend an approach to the sensitized candidate.