Pathophysiology of Corneal Graft Rejection

The cornea is the most frequently transplanted tissue in the human body. The primary cause of corneal graft failure is immune rejection, a highly complex sequence of innate and adaptive immune responses that interact to promote tissue destruction. As our understanding of the effector pathways that drive allograft rejection has deepened, so too has our comprehension of the diverse immunoregulatory mechanisms that restrain the effector response and promote graft tolerance. This chapter reviews the incidence, the risk factors and the cellular and molecular mechanisms that underlie corneal allograft rejection. The amalgam of anatomical features, immune cells, and immunoregulatory factors that promote tolerance and immune quiescence are described. Finally, possibilities for future therapeutic approaches to promote graft survival are considered.