Comparison of kidney transplant outcomes in HLA compatible and incompatible transplantation: A national cohort study
Trijntje J. W. Rennie, Richard Battle, Angela A. Abel, Sylvia McConnell, R. A. McLaren, Paul J. Phelan, Colin Geddes, Neal Padmanabhan, Marc Clancy, Ann‐Margaret Little, David M. Turner
Abstract
Abstract Background Reports of HLA incompatible (HLAi) kidney transplant outcomes are inconclusive, especially in the context of lower level Donor Specific Antibodies (DSA). Methods Multi‐centre national cohort study of HLAi kidney transplant recipients matched in 1:2 ratio with HLA compatible (HLAc) kidney transplant recipients. HLAi defined as DSA identified by Luminex. Antibody mediated rejection (AMR) and transplant‐survival were analysed using Kaplan–Meier plots. Propensity score (PS) matching was used to compare recipient and transplant survival between groups. Results We included 61 HLAi and 122 HLAc recipients; mean age 46 years; 60% female. MFI T0 : 3327 (IQR 1352–6458), 23 (38%) were Flow cytometry crossmatch positive (FC‐XM POS ). DSA POS /FC‐XM POS transplantation carried an increased risk of AMR at 1 year (52%) compared to DSA POS /FC‐XM NEG (27%) and HLAc (0%). Unadjusted death censored graft loss at 3 years was 13% (HLAi) and 8% (HLAc). Three‐year patient survival was 95% in HLAc, 84% in DSA POS /FC‐XM NEG and 69% in DSA POS /FC‐XM POS recipients; 58% of HLAi deaths were infection‐related. HLA incompatibility was associated with a decreased 3‐year survival in our PS‐matched cohort. Conclusion In kidney transplantation, DSA and positive FC‐XM carries an increased risk of AMR. Despite inferior transplant and survival outcomes compared to HLAc transplantation, it remains a realistic option for highly sensitized patients facing prolonged waiting times and reduced survival on dialysis.