Anatomic variability of rejection in intestinal allografts after pediatric intestinal transplantation

Rejection of the allograft is a major contributor to morbidity and mortality in children who undergo a small intestinal transplant. Operational definitions for histologic rejection have been established, but little is known about the anatomic variability of the histologic abnormalities.

Biopsy reports were reviewed retrospectively from more than 1200 endoscopies performed on the 41 children who received intestinal transplantation between 1990 and 1995.

Biopsies were performed in the proximal jejunum and distal ileum allograft simultaneously on 248 occasions. In 168 biopsies, neither site was histologically abnormal; in 80, rejection was found. In 42, both regions were abnormal; however, in 17 only the jejunum was involved and in 21 the rejection exclusively involved the ileum. Among children whose allograft included colon, rejection was absent in colon and ileum in 34 biopsies, involved both in 6, involved ileum but not colon in another 6 and involved colon but not ileum in only one. When the allograft included stomach, rejection was absent in the stomach and jejunum 39 times, involved both sites 8 times, involved jejunum and not the stomach 10 times, but involved the stomach and not jejunum only once. Endoscopic appearance correctly predicted histologic rejection 63% of the time.

Anatomic variability may exist in the rejection process. Sampling the jejunum and ileum seems to have similar sensitivity in detecting rejection, whereas sampling stomach and the colon is less sensitive. When allograft rejection is suspected on clinical grounds, sampling more than one area of the graft may be necessary for histologic confirmation.