Histopathology of xenografts in pig to non-human primate discordant xenotransplantation.

Xenotransplantation could provide a solution to the critical shortage of organs for transplantation in humans. Swine have been proposed as a suitable donor species. Swine organs, however, when transplanted to primates, are rapidly rejected by hyperacute rejection (HAR) and acute humoral xenograft rejection (AHXR). Both HAR and AHXR are triggered by xenoreactive natural antibodies directed against a specific epitope (galactose alpha1-3 galactose: Gal) on porcine vascular endothelium. In attempt to prevent HAR and AHXR, alpha1,3-galactosyltransferase gene knockout (GalT-KO) pigs have been produced. GalT-KO pig organs do not express the Gal epitope (antigen), and it therefore can eliminate the anti-Gal antibody--Gal antigen immunoreaction in xenotransplantation. We reported our initial study of kidney transplantation from GalT-KO miniature swine to baboons with either immunosuppression protocol or with a tolerance inducing protocol. Here, we discussed the pathology of xenografts in GalT-KO pig to non-human primate kidney transplantation.