Transplantation tolerance: memories that haunt us

Abstract

Transplant tolerance, which allows grafts--allogeneic cells, tissues, or organs--to be accepted without host immunosuppression, can be achieved in mice but not in primates. In this issue of Science Translational Medicine, Nadazdin et al. report that a high pretransplant frequency of graft-reactive memory T cells may inhibit the induction of transplant tolerance in nonhuman primates and lead to transplant rejection. Knowing the frequency of allograft-specific memory T cells in potential transplant recipients could aid clinical decision-making by guiding selection of the antigenic profile of the donor organ or by influencing the type of tolerance-induction protocol pursued.