title: High transplant rates of highly sensitized recipients with virtual crossmatching in kidney paired donation.
abstract: BACKGROUND
  In kidney paired donation (KPD), flexibility in the allocation of incompatible pairs is required if a critical mass of pairs to efficiently find matches cannot be reached.
  
  
  METHODS
  In the Australian KPD program, virtual crossmatch is used for the allocation of suitable donors to registered recipients. Matching is based on acceptable mismatches, and donors are excluded from matching to recipients with donor-specific antibodies (DSAs) greater than 2000 mean fluorescence intensity (MFI). Match and transplant rates in the first year of the program were reviewed with respect to recipient and donor characteristics, including blood group distribution, level of recipient's sensitization, and postallocation crossmatches.
  
  
  RESULTS
  Four quarterly match runs were performed, which included 53 pairs and 2 altruistic donors. Human leukocyte antigen incompatibility accounted for 90% of the listed pairs. In the second run, the DSA threshold was increased to greater than 8000 MFI, because no matches were found with standard allocation. Optional ABO-incompatible matching was introduced from run 3. Matches were identified in 37 (70%) patients, of whom 92% had a negative crossmatch with their matched donor. Crossmatch positive results were found only in recipients with DSAs greater than 2000 MFI in the second run. In 4 cases immunological reasons and in 4 cases other reasons resulted in breakdown of chains and 17 patients not progressing to transplantation. Eventually, 20 (38%) patients received a KPD transplant, and 35% of these had a calculated panel-reactive antibody greater than 90%.
  
  
  CONCLUSIONS
  KPD using virtual crossmatch is a valid and effective solution for patients with immunologically incompatible donors even in the context of highly sensitized recipients.
authors.affiliation: Department of Nephrology, Fremantle Hospital, Perth, Western Australia, Australia. paolo.ferrari@health.wa.gov.au
authors.forename: Paolo
authors.initials: P
authors.lastname: Ferrari
authors.forename: Samantha
authors.initials: S
authors.lastname: Fidler
authors.forename: Rhonda
authors.initials: R
authors.lastname: Holdsworth
authors.forename: Claudia
authors.initials: C
authors.lastname: Woodroffe
authors.forename: Gabriella
authors.initials: G
authors.lastname: Tassone
authors.forename: Narelle
authors.initials: N
authors.lastname: Watson
authors.forename: Linda
authors.initials: L
authors.lastname: Cantwell
authors.forename: Greg
authors.initials: G
authors.lastname: Bennett
authors.forename: Alycia
authors.initials: A
authors.lastname: Thornton
authors.forename: Frank T
authors.initials: FT
authors.lastname: Christiansen
authors.forename: Lloyd
authors.initials: L
authors.lastname: D'Orsogna
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology; D000465:Algorithms; D000533:Altruism; D001315:Australia; D001787:Blood Group Incompatibility / Q000276:immunology; D046148:Donor Selection; D006680:HLA Antigens / Q000276:immunology*; D006648:Histocompatibility; D006650:Histocompatibility Testing; D006801:Humans; D007518:Isoantibodies / Q000097:blood*; D016030:Kidney Transplantation / Q000276:immunology*; D019520:Living Donors; D015397:Program Evaluation; D013997:Time Factors; D009927:Tissue and Organ Procurement; D016896:Treatment Outcome
chemical_list: D000017:ABO Blood-Group System; D006680:HLA Antigens; D007518:Isoantibodies