Corneal Graft Rejection

Corneal transplantation is arguably the oldest, most common, and most successful form of solid tissue transplantation. Over 60,000 corneal transplants are performed each year worldwide, and of that number, approximately 33,000 are performed annually in the United States alone. The popularity reflects the success rate for a corneal graft. The prognosis for an uncomplicated, first time full-thickness penetrating keratoplasty is as high as 90% at 2 years under cover of topical corticosteroids, without the need for human leukocyte antigen (HLA) tissue typing or systemic immunosuppressive agents such as with other organ transplantation surgeries. However, corneal graft rejection remains the leading cause of graft failure. In 1981, Alldrege and Krachmer found that corneal graft rejection occurs in up to 50% of recipients and is the single most important reason for graft failure. In the early 1990s, according the Australian graft registry, irreversible rejection accounted for at least 33% of all graft failures. It is a complex immune process involving donor tissue recognition and destruction of graft cells by allospecific immune cells of the recipient, which may lead to reversible or irreversible decompensation of the transplanted cornea.