Role of complement in graft rejection after organ transplantation

Activation of the complement system may significantly contribute to the inflammatory reaction after solid organ transplantation. In allotransplantation, the complement system may be activated by ischemia/reperfusion and, possibly, by antibodies directed against the graft. In xenotransplantation from nonprimates to primates, the major activators for complement are preexisting antibodies. Studies in animal models have shown that the use of complement inhibitors may significantly prolong graft survival. This review describes the role of the complement system in organ injury after organ transplantation and the use of complement inhibitors to prevent damage to the graft after allo- or xenotransplantation.