Induction of graft-versus-host disease and rejection by sensitized small bowel allografts.

This study was undertaken to investigate under which circumstances graft versus host disease occurs following fully allogenic small bowel transplantation in the rat. To facilitate the development of GVHD, Brown-Norway donors were specifically sensitized against the Lewis hosts prior to transplantation. Additionally, the Lewis recipients were immunocompromised before transplantation using splenectomy, cyclosporine, and antilymphocyte serum. No further immunosuppressive therapy was administered after transplantation. When all pretreatment regimens were used, acute lethal GVHD arose in two of nine animals (22%), whereas in two animals (22%) signs of acute GVHD and rejection were observed concurrently. When recipients of sensitized grafts were pretreated with CsA alone, one of eight animals (12.5%) showed signs of GVHD and rejection. All other animals died of acute rejection without clinical signs of acute GVHD. However, histological signs of GVHD were observed frequently in hosts grafted with a sensitized small bowel transplant. These data show that acute lethal GVHD can occur when an immunocompromised host is grafted with a sensitized intestinal transplant.