2519: Development of de novo donor-specific HLA antibodies after combined intestinal and vascularized composite allotransplantation

2519: Development of de novo donor-specific HLA antibodies after combined intestinal and vascularized composite allotransplantation Annemarie Weissenbacher, MD, Georgios Vrakas, Mian Chen, Srikanth Reddy, Susan Fuggle, and Peter Friend Oxford Transplant Centre, Oxford, UK Background In the young field of VCA as well as in bowel and multivisceral transplantation, the occurrence of DSA has been described Our aim was to investigate the incidence and clinical effect of de novo (dn) DSA in our cohort of patients receiving an intestinal transplant together with a vascularised abdominal wall graft Methods This is a single-center, retrospective clinical study The patient cohort includes all recipients of deceased donor intestinal and VCA transplants performed at the Oxford Transplant Centre between October 2008 and December 2015 Pre-transplant HLA antibody status was available for all patients Results Thirty-two intestinal transplants were included One patient underwent a second small bowel and abdominal wall transplant All organs were retrieved from DBD donors There were 8 modified multivisceral transplants (8/32, 25%) and 24 isolated small bowel transplants (24/32, 75%) An abdominal wall (from the same donor) was used in 18 cases (18/32, 56%) All patients received alemtuzumab induction and tacrolimus maintenance immunosuppression DSA were detectable in 2/31 (65%) recipients before the combined transplant Twelve (387%), of the remaining 29, developed dnDSA Five patients developed dnDSA against HLA class-I (156%), 4 against classII (125%) and 3 (94%) against both classes The mean MFI was 3094 § 5642 SD In the VCA group, a lower percentage developed dnDSA compared to the group without VCA; 6/14 (429%) vs 6/18 (33%) Intestinal rejection was proven in 5/14 (357%) cases without VCA and 3/18 (167%) cases with the VCA VCA rejection was seen in 7/18 (389%) cases One was grade 1, 1 grade 2 and 5 grade 3 There were no episodes of intestinal rejection without VCA rejection The occurrence of dnDSA in the absence of clinical rejection has not led to organ or patient deterioration and has not been treated Conclusion The combination of intestinal transplantation with a VCA is immunologically complex: although we have found no evidence that the VCA sensitizes the patient, predisposing to rejection of both organs, further experience is needed Our data suggest that combining an abdominal wall VCA with an intestinal transplant does not increase the incidence of dnDSA. CONTACT Annemarie Weissenbacher, MD annemarie.weissenbacher@nds.ox.ac.uk © 2016 Annemarie Weissenbacher, Georgios Vrakas, Mian Chen, Srikanth Reddy, Susan Fuggle, and Peter Friend. Published with license by Taylor & Francis. This is an Open Access article distributed under the terms of the Creative Commons Attribution-Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The moral rights of the named author(s) have been asserted. VASCULARIZED COMPOSITE ALLOTRANSPLANTATION 2016, VOL. 3, NOS. 1–2, 17 http://dx.doi.org/10.1080/23723505.2016.1232937