Graft versus host disease in small bowel transplantation.

Quantities of organized lymphoid tissue in small bowel allografts may cause graft versus host disease (GVHD) following transplantation. This study examines the effect of graft mesenteric lymphadenectomy on development of GVHD following small bowel transplantation in rats. GVH reactivity was assessed by measuring the degree of graft cell emigration to the host. In the PVG to DA strain combination, graft mesenteric lymphadenectomy led to a significant reduction in graft cell colonization of host lymphoid tissues from 40–50 per cent to 25–35 per cent. Transplantation from PVG to (PVG × DA)F1 hybrids caused fatal GVHD within 21 days whereas when DA donors were used survival was over 30 days. When mesenteric lymphadenectomy was performed on PVG donors, host survival increased by only 3–4 days. Mesenteric lymphadenectomy in DA donors led to long-term recipient survival with no GVHD. Intensity of GVHD following rat small bowel transplantation is a strain-dependent phenomenon and graft mesenteric lymphadenectomy does not always prevent GVHD. The mucosa may have an important immunological role.