Acute Cellular Rejection in Small Bowel Transplantation: The Nebraska Experience
Benjamin J Swanson, Wendy J Grant, Stanley J Radio. University of Nebraska Medical Center, Omaha, NE
Background: Acute cellular rejection (ACR) is a significant complication of small bowel transplantation. Since the 2003 Eighth International Small Intestinal Transplantation Symposium, a standardized grading system has existed for evaluation. Other authors have noted significant rates of biopsies graded as indeterminate and mild while we have observed lower rates for both grades. The aim of this study was to document the frequency of the grades of ACR and to determine if the grade correlated with length of duration of acute rejection.
Design: All small bowel transplant mucosal biopsies performed at our instituition from Janurary 2004 to September 2011(2082 biopsies from 235 patients) were retrospectively analyzed. Specimens were assigned as: no evidence of ACR (grade 0), indeterminate for ACR, mild ACR (grade 1), moderate ACR (grade 2), severe ACR (grade 3), treated/on-going rejection, or no crypts present to evaluate ACR. The length of each ACR episode was determined by the time from index biopsy to the first of two consecutive grade 0 biopsies. Other findings such as PTLD, CMV enteritis, and adenovirus enteritis were also documented.
Results: The distribution of ACR was as follows: grade 0 (84.6%), indeterminate for ACR (5.5%), grade 1 (4.6%), grade 2 (1.7 %), grade 3 (1.6%), treated/on-going rejection (1.5%), no crypts present to evaluate ACR (1.3%). The average length of each rejection episode for a given grade was as follows: grade 1 (14.6 days +/- 11.8 days), grade 2 (53.3 days +/- 90.1 days), grade 3 (43.4 days +/- 49.6 days). The average length of rejection was statistically significant between episodes called mild versus moderate (p<0.05). However, there was no statistically significant difference in length of rejection between episodes called moderate versus severe (p=0.54).
Conclusions: Acute Cellular Rejection is an uncommon but significant complication of small bowel transplantation. These findings demonstrate a low frequency of biopsies graded as indeterminate at our institution. Although there was a statistically significant difference in rejection time between mild and moderate ACR, no such difference existed between moderate and severe ACR in this analysis. Finally, these findings demonstrate that the current grading scheme may correlate with length of acute cellular rejection.
Monday, March 19, 2012 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 118, Monday Morning