REG3α is a novel biomarker that potentially correlates with acute allograft rejection after intestinal transplantation.

Monitoring of intestinal allograft function remains a challenge. While frequent endoscopies and biopsies are the gold standard, no single biomarker exists to screen for intestinal transplant rejection. The novel REG3α, an antimicrobial peptide secreted by intestinal enterocytes and Paneth cells, has been associated with inflammatory bowel disease as well as intestinal graft versus host disease. Our aim was to identify and describe a role of REG3α in monitoring or predicting acute allograft rejection after intestinal transplantation (ITx). Since 2019, we have incorporated REG3α into the standard monitoring of patients after ITx. We conducted a retrospective analysis of a prospectively maintained IRB-approved database and present, herein, the results of 2 adults with irreversible intestinal failure who underwent isolated ITx under this monitoring protocol. Increases in REG3α corresponded with acute allograft rejection in both cases and preceded acute allograft rejection by 1 week in one of the cases. We describe REG3α as a non-invasive marker of acute allograft rejection after adult isolated ITx which not only corresponded with acute allograft rejection but also preceded histopathological changes by 1 week.