Alloimmunity and Tolerance in Corneal Transplantation

Corneal transplantation is one of the most prevalent and successful forms of solid tissue transplantation. Despite favorable outcomes, immune-mediated graft rejection still remains the major cause of corneal allograft failure. While ‘low risk’ graft recipients with uninflamed graft beds enjoy a success rate of approximately 90%, the rejection rates in inflamed graft beds or ‘high risk’ recipients often exceed 50% despite maximal immune suppression. In this review we discuss the critical facets of corneal alloimmunity, including immune and angiogenic privilege, mechanisms of allosensitization, cellular and molecular mediators of graft rejection, and allotolerance induction