Hsinlin Tsai^1,2, Andreas G. Tzakis², Eddie Island², Ignacio Gonzalez-Pinto^2,3, Panagiotis Tryphonopoulos², Seigo Nishida², Jang Moon², Jeiwen Chang^1,2, David Levi², Debbie Weppler², Phillip Ruiz², Gennaro Selvaggi², Akin Takin², Oscar Kuang-Sheng Lee¹, E. Steve Woodle⁴

¹Taipei Veterans General Hospital, Taipei, Taiwan; ²Department of Surgery, Division of Transplantation, Leonard M. Miller School of Medicine, Miami, FL, United States; ³Department of Surgery, Hospital Universitario Central de Asturias, Universidad de Oviedo, Oviedo, Austuria, Spain; ⁴Department of Surgery, University of Cincinnati, Cincinnati, OH, United States

Background: Donor specific antibodies (DSA) are associated with acute kidney graft rejection, but their role in small bowel (SBT)/ multivsceral (MVT) allograft remains unclear. We carried out a prospective study to understand the impact of DSA in the setting of intestinal allograft rejection.

Methods: Thirteen patients (15 grafts) were serially evaluated for DSA levels pre- and post-transplant. DSA was determined by Luminexand the results were interpreted as fluorescence intensity (FI), with FI>3000considered positive.

Results: The clinical rejection episodes in allografts were significantly associated with the presence of DSA (p=0.041).We obtained 291 biopsy samples from graft ileum and date-matched DSA assay reports. Sixty three (21.65%) of the biopsies showed acute rejection. The appearance of DSA were pre-formed (n=5, Anti-HLA Class II=3, Anti-Class I and II=2), de novo(n=4, 15.25±4.72 days after transplantation, Anti-Class II=1, and Anti-Class I and II= 3) and never (n=6).Among the 63 biopsies, 30(47.6%) had significant correlations with positive DSA (kappa=0.30, p<0.001) and manifested severe rejection grade (p=0.009).

Conclusions: In this cohort of SBT/MVT patients, there was a high incidence of DSA. The presence of DSA should alert the clinical team of a higher risk of rejection, and reduction of the FI is clinically associated with resolution. Serial endoscopy guided biopsies combined with simultaneous DSA measurement in post intestinal transplantation follow up is an effective means of screening for cellular and humoral based forms of acute rejection.