Non-tuberculous mycobacterial associated enterocolitis in intestinal transplantation

Zoom endoscopic monitoring of small bowel allograft rejection

BACKGROUND

The small bowel has been successfully transplanted in patients with irreversible intestinal failure. This report aims to describe endoscopic monitoring of small bowel rejection.

METHODS

A magnification endoscope (zoom endoscope) was used in this study. In the first part of the study (October 1998 to March 2000, 271 endoscopy sessions), the specific endoscopic findings that correlated with rejection were determined. An analysis then was performed on data from the second period (March 2001 to November 2002, 499 sessions) to evaluate the zoom endoscope's accuracy in monitoring rejection.

RESULTS

Specific endoscopic findings of rejection found in the first period included background erythema, villous congestion, blunted villous tip, and shortened villous height. When the rejection was successfully treated, endoscopic appearance returned to normal. On the basis of these findings, five endoscopic criteria (villous shortening, villous blunting, background erythema, villous congestion, and mucosal friability) were used to score endoscopic sessions in the second period. Endoscopic diagnosis of rejection was compared with histology. Adult patients showed a sensitivity of 45%, a specificity of 98%, a positive predictive value of 82%, and a negative predictive value of 88%. In pediatric patients, these values were, respectively, 61%, 84%, 57%, and 86%. On 59 distinct occasions (30 in period 1 and 29 in period 2) in which the results were endoscopy negative yet biopsy positive (mild) for rejection, we elected not to treat these rejections on the basis of clinical evaluation, and 58 (98%) resolved without further therapy.

CONCLUSIONS

With the use of magnification, endoscopy is a useful tool for monitoring acute rejection in the small bowel allograft.

Small bowel transplantation

The development of small bowel transplantation has long been hindered by the immunological and infectious barriers peculiar to the small bowel. Gradual progress has been achieved during the past decade with the use of tacrolimus and the availability of better anti-infection prophylaxis. The current status of small bowel transplantation as a life-saving option for patients failing on total parenteral nutrition and those who have developed irreversible liver failure is undisputed. Small bowel transplantation can be performed as either an intestine-only graft or as part of a composite graft with the liver and, on occasion, other organs. The various techniques of donor and recipient operations are relatively standardized. Despite the progress made, the most common causes of death and graft loss continue to be sepsis, rejection, and lymphomas. Further progress can be achieved by development of more effective immunosuppressive and immunomodulatory strategies. The role of inducing chimerism by adjuvant donor-specific bone marrow transfusions to promote graft tolerance is uncertain. Until the mortality and graft losses are further reduced, the role of small bowel transplantation will be limited to a salvage procedure for failure of total parenteral nutrition rather than a primary treatment of intestinal failure.