Spectrum of the early xenograft response: From hyperacute rejection to delayed xenograft injury

Abstract

Hyperacute xenograft rejection is a well-defined barrier to clinical pig-to-human xenotransplantation, and intense research in this area has identified potential solutions. In contrast, the next phase of xenograft injury, which can occur days to weeks later, has introduced a new series of immunological and nonimmunological barriers with complex mechanisms. This review addresses mechanisms of the immediate and delayed xenograft response with a focus on the relevant components. The key individual elements include carbohydrate antigens and natural antibodies to these epitopes, the role of the complement and coagulation systems, and the inflammatory cellular xenograft response that is predominan..