R. Higgins¹, A.J. Hudson², R.J. Johnson², S.V. Fuggle³, J. Galliford⁴, D. Taube⁴, N. Mamode⁵, S. Ball⁶, R. Ravanan⁷, N. Torpey⁸, R. Thuraisingham⁹, A. Gupta⁹, C. Newstead¹⁰, J.A. Bradley^11
1Department Of Renal Medicine, University Hospital Coventry & Warwickshire, Coventry/UNITED KINGDOM, ²Statistics And Clinical Audit, NHS Blood and Transplant (UK), Bristol/UNITED KINGDOM, ³Scientific Advisor, NHS Blood and Transplant (UK), Bristol/UNITED KINGDOM, ⁴Wlrtc, Hammersmith Hospital, London/UNITED KINGDOM, ⁵Mrc Centre For Transpantation, King's College London, London/UNITED KINGDOM, ⁶Nephrology And Transplantation, Queen Elizabeth Hospital, Birmingham/UNITED KINGDOM, ⁷Renal And Transplant Unit, Southmead Hospital, Bristol/UNITED KINGDOM, ⁸Transplant Unit, Addenbrookes Hospital, Cambridge/UNITED KINGDOM, ⁹Transplant Unit, Royal London Hospital, London/UNITED KINGDOM, ¹⁰Nephrology, St James's University Hospital, Leeds/UNITED KINGDOM, ¹¹Department Of Surgery, University of Cambridge, Cambridge/UNITED KINGDOM

Body: Introduction. Antibody incompatible renal transplantation (AIT) is now widely practiced, but there remain uncertainties about outcomes. The UK Registry is the first comprehensive national registry for HLA and ABO AIT. Methods. Comprehensive data for all UK transplants are already collected. An additional AIT dataset was introduced in 2008, collecting data on transplants since 2001 with ABO incompatibility (ABOi), or donor specific HLA antibodies (HLAi) detectable in the immediate pre-transplant period. Those with historic positive, current negative DSA were not included. Results. 381 AIT transplants have been performed; 213 HLAi, 150 ABOi (37 full reports to registry awaited), and 18 were both HLAi and ABOi. In 2009, of the 972 living donor transplants performed in the UK, 49 (5%) were HLAi, and 64 (7%) were ABOi. Fourteen centres reported HLAi transplants, number per unit ranging from 1-76. The pre-treatment complement dependent cytotoxic (CDC) crossmatch (XM) (non AHG enhanced) was +ve in 29% of cases. Flow cytometric (FC) XM was +ve but CDC XM –ve in 49%, and 22% had donor specific antibodies (DSA) detectable only by microbead or other solid phase assay. 106 (46%) were first grafts; 94 (41%) were second; 23 (10%) were third and 8 (3%) were fourth grafts. 179 (77%) grafts used kidneys from a living donor while 52 (23%) used kidneys from a deceased donor. Centres used different combinations of IVIg and CD20 as well as plasmapheresis prior to transplantation. For ABOi cases, excluding the HLAi and ABOi cases, 146 were planned ABOi in living transplants, 3 were deceased donor transplants in a planned programme of A2 donor into selected B recipients at a single centre, and there was 1 other O recipient who received an A donor kidney. ABO antibodies were removed with plasmapheresis in 76% of cases, antigen-specific absorption in 18%, and 6% had no antibody removal. Three year graft survival (death and graft loss) was 84 (95% CI 69-92)% in ABOi transplant, and 82 (73-88)% in HLAi transplants, compared with 92 (91-93)% for all other living donor transplants, and 84 (83-85)% for all other deceased donor transplants. Conclusion. 12% of living donor renal transplants performed in the UK in 2009 were antibody incompatible, and over three quarters of the transplant units in the UK have reported AIT transplants to the Registry. Overall three year graft survival rates were comparable with the results of ‘antibody compatible’ deceased donor transplantation. The dataset will allow further analysis by specificity and level of donor specific HLA antibody transplants, and outcomes according to blood group mismatch and prior HLA sensitisation in ABOi transplants.

Disclosure: All authors have declared no conflicts of interest.