Histologic Analysis of Chronic Rejection in Small Bowel Transplantation: Mucosal and Vasculqr Alterations

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.