Results of gal-knockout porcine thymokidney xenografts

Am J Transplant. 2009 Dec;9(12):2669-78. doi: 10.1111/j.1600-6143.2009.02849.x. Epub 2009 Oct 21.


Clinical transplantation for the treatment of end-stage organ disease is limited by a shortage of donor organs. Successful xenotransplantation could immediately overcome this limitation. The development of homozygous alpha1,3-galactosyltransferase knockout (GalT-KO) pigs removed hyperacute rejection as the major immunologic hurdle to xenotransplantation. Nevertheless, GalT-KO organs stimulate robust immunologic responses that are not prevented by immunosuppressive drugs. Murine studies show that recipient thymopoiesis in thymic xenografts induces xenotolerance. We transplanted life-supporting composite thymokidneys (composite thymus and kidneys) prepared in GalT-KO miniature swine to baboons in an attempt to induce tolerance in a preclinical xenotransplant model. Here, we report the results of seven xenogenic thymokidney transplants using a steroid-free immunosuppressive regimen that eliminated whole-body irradiation in all but one recipient. The regimen resulted in average recipient survival of over 50 days. This was associated with donor-specific unresponsiveness in vitro and early baboon thymopoiesis in the porcine thymus tissue of these grafts, suggesting the development of T-cell tolerance. The kidney grafts had no signs of cellular infiltration or deposition of IgG, and no grafts were lost due to rejection. These results show that xenogeneic thymus transplantation can support early primate thymopoiesis, which in turn may induce T-cell tolerance to solid organ xenografts.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Creatinine / blood
  • Galactosyltransferases / genetics*
  • Gene Knockout Techniques
  • Kidney Transplantation / immunology*
  • Kidney Transplantation / methods
  • Papio / immunology
  • Proteinuria / etiology
  • Swine
  • Swine, Miniature / immunology
  • Thymus Gland / transplantation*
  • Transplantation, Heterologous / immunology*


  • Creatinine
  • Galactosyltransferases
  • N-acetyllactosaminide alpha-1,3-galactosyltransferase