الفهرس | Only 14 pages are availabe for public view |
Abstract Penetrating keratoplasty is the most widely practiced type of transplantation in humans. Irreversible immune rejection of the transplanted cornea is the major cause of human allograft failure in the intermediate and late postoperative period. This immunological process causes reversible or irreversible damage to the grafted cornea in several cases despite the use of intensive immunosuppressive therapy. Corneal graft rejection comprises a sequence of complex immune responses that involves the recognition of the foreign histocompatibility antigens of the corneal graft by the host’s immune system, leading to the initiation of the immune response cascade. Risk factors for corneal graft rejection include corneal vascularization, anterior synechiae, irritating sutures, active inflammation, regrafting, additional surgery, trauma, history of graft rejection, recurrence of herpes, eccentric grafting and corneal scarring on the graft. Prevention of immune-mediated graft rejection aims at minimizing antigenic difference between the host and the donor tissue and reducing the antigenic load of donor tissue, meticulous surgical technique, including avoiding decentration of the recipient bed cut, optimal suturing, and good graft--host apposition. Controlling the host immune response to the foreign |