Colon vs small bowel rejection after total bowel transplantation in a pig model.

With the advent of FK 506, small bowel transplantation has become clinically feasible. Both clinically and experimentally, jejunal and ileal biopsies are used for early diagnosis of rejection. More recently, the colon, in addition to the small bowel, has been transplanted to decrease the high incidence of diarrhea after small bowel transplantation. A Bishop-Koop ileostomy allows biopsies on a regular basis, but the diagnosis of rejection remains a problem after takedown of the ileostomy. Rejection of the ileum is more frequent and more severe than rejection of the jejunum or the colon. Colon biopsy after ileostomy takedown would not rule out rejection of the ileum.