Histologic Analysis of Chronic Rejection in Small Bowel Transplantation

Background Chronic rejection is a significant barrier to small bowel allograft survival. Although chronic rejection primarily involves vessels of the submucosa, serosa, and mesentery, some mucosal alterations have been suggested to be correlative. Methods We retrospectively investigated explanted small bowel allografts for clinical characteristics and histological alterations in the mucosa, submucosa, and serosa. Results Crypt epithelial mucin loss, submucosal fibrosis, and length of time to explant were all statistically associated with chronic rejection. Medium-sized and large-sized vessels of the serosa and mesentery preferentially demonstrated histologic changes of chronic rejection. Conclusion These results further define chronic vascular rejection and the relationship between the mucosal changes and chronic rejection.