Method Background Result Conclusion Peri-Transplant Blood Transfusion Is Associated With Significant Formation of HLA Antibodies Despite Immunosuppression 1Central Northern Adelaide Renal & Transplantation Service, Royal Adelaide Hospital, Adelaide SA 5000, Australia 2 Australia and New Zealand Dialysis and Transplantation Registry, Royal Adelaide Hospital, Adelaide SA 5000, Australia 3 National Transplantation Services Australian Red Cros4 Discipline of Medicine, University of Adelaide, 5Transfusion Service Royal Adelaide Hospital, Frome Road, Adelaide SA 5000 6Centre for Stem Cell Research, University of Adelaide, Frome Road, Adelaide SA 5000, Australia Ubaidullah S.Dawood1, William Hanf1, Blair Grace2,4, Chris J. Drogemuller1,6, Greg D. Bennett3, Robert P. Carroll1, 3, 4,6, Stephen P. McDonald1, 2, 4,6, Sophia Hague5, P. Toby H. Coates1, 3, 4, 6,* Background Result Blood transfusion in kidney transplantation is considered a major risk for sensitisation. We studied the prevalence of transfusion during the transplantation period and analysed the impact on HLA antibody status. 187 patients underwent kidney transplantation during the study period (2010-13).Haemoglobin at the time of surgery were 120g/L (range 120-164) in non-transfused cohort and 116g/L (range 87-155) among the transfused cohort. 67 (36%) received blood transfusion during peri-transplantation period [mean of 2 units (range 2-14)].Mean recipient age of transfused patient was 51 +/- 12 years (36M/53F). Prior to transplantation 40/67 recipients had non-donor specific HLA antibodies and 9/67 had pre-existing DSA. We observed the formation of de novo HLA antibodies (MFI >300) in 18/67 (26%) patients with 8 HLA Class I, 5 HLA class II and 5 for both classes. The HLA antibody specificity for class I Ab was HLA B (n=11) and the HLA class II Ab was DR (n=7). We also found 4 de novo Cw locus Ab and 1 DP Ab. 5 patients developed de novo DSA after transplantation. Method We retrospectively analysed all adult kidney recipients from a single centre transfused with red blood cells and platelets during the first 48 hours of transplantation surgery. HLA tissue typing was performed by single antigen Luminex bead assay (Tepnel). HLA antibodies and donor specific antibodies (DSA) pre and post-transplantation between days 14 and 31 were analysed. All patients received prednisolone, tacrolimus and MMF. Conclusion 1) High prevalence of transfusion in peri- transplantation period (36%) 2) 26% of transfused kidney transplant recipient developed clinically significant HLA antibodies (MFI>300). 3) High prevalence of transfusion and sensitization in young patients may potentially impact future transplantation. 4)Second graft, female patient, AKPKD and non Caucasian race has higher likelihood of developing de novo HLA antibodies in our study as demonstrated in forest plot (fig1 and 2) Fig 1 Fig 2