title: ABO-incompatible matching significantly enhances transplant rates in kidney paired donation.
abstract: BACKGROUND
  Although preformed donor-specific anti-human leukocyte antigen antibodies (DSA) can be overcome by plasmapheresis-based strategies with some success in renal transplantation, kidney paired donation (KPD) is a more effective strategy to avoid DSA. In contrast, ABO incompatibility can be crossed with outcomes equivalent to ABO-compatible transplantation. Here, we report the ability of accepting human leukocyte antigen-compatible but ABO-incompatible donors to increase the number of exchanges in a KPD program.
  
  
  METHODS
  In the Australian KPD program, virtual crossmatch is used to allocate suitable donors to recipients. Acceptance of ABO-incompatible donors is allowed in cases where anti-blood group antibody titres are deemed amenable to removal by apheresis or immunoabsorption. The number of matched recipients, identified chains, and transplants performed with and without acceptance of ABO incompatibility was analyzed.
  
  
  RESULTS
  In 2 years, 115 pairs were included in nine quarterly match runs. Incompatibility due to DSA accounted for 86% of the listed pairs and 52% were also blood group incompatible to their coregistered donor. Median calculated panel-reactive antibody in registered recipients was 83% (mean, 67%±37%). ABO-incompatible donors were accepted for 36 patients. Two waitlist recipients and 48 KPD candidates were matched and transplanted. Ten recipients (20%) of an ABO-incompatible donor kidney were distributed across 8 chains that resulted in 21 recipients being transplanted. Thus, without ABO-incompatible matching, only 27 recipients in 12 chains would have been transplanted.
  
  
  CONCLUSIONS
  Acceptance of blood group-incompatible donors for patients with low to moderate anti-blood group antibody significantly increases transplant rates for highly sensitized recipients.
authors.affiliation: 1 Department of Nephrology, Fremantle Hospital, Perth, Western Australia, Australia. 2 School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia, Australia. 3 Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia. 4 Department of Nephrology, Western Hospital, Footscray, Victoria, Australia. 5 University of Melbourne, Melbourne, Victoria, Australia. 6 Department of Immunology, PathWest, Royal Perth Hospital, Perth, Western Australia, Australia. 7 School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Western Australia, Australia. 8 Address correspondence to: Paolo Ferrari, M.D., Australian Paired Kidney Exchange Program, Department of Nephrology, Fremantle Hospital, School of Medicine and Pharmacology, University of Western Australia, Perth WA 6160, Australia.
authors.forename: Paolo
authors.initials: P
authors.lastname: Ferrari
authors.forename: Peter D
authors.initials: PD
authors.lastname: Hughes
authors.forename: Solomon J
authors.initials: SJ
authors.lastname: Cohney
authors.forename: Claudia
authors.initials: C
authors.lastname: Woodroffe
authors.forename: Samantha
authors.initials: S
authors.lastname: Fidler
authors.forename: Lloyd
authors.initials: L
authors.lastname: D'Orsogna
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D000328:Adult; D001315:Australia; D001787:Blood Group Incompatibility / Q000276:immunology*; D001788:Blood Grouping and Crossmatching; D003198:Computer Simulation; D046148:Donor Selection; D005260:Female; D006680:HLA Antigens / Q000276:immunology; D006648:Histocompatibility; D006801:Humans; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D013997:Time Factors; D014019:Tissue Donors / Q000600:supply & distribution*; D016896:Treatment Outcome; D014850:Waiting Lists
chemical_list: D000017:ABO Blood-Group System; D006680:HLA Antigens