title: Application of calculated panel reactive antibody using HLA frequencies in Koreans.
abstract: BACKGROUND
  Introduction of the Luminex panel reactive antibody (PRA)-single antigen (SA) assay has increased the detection rates of unacceptable antigens in sensitized patients; the calculated PRA (CPRA) level represents the percentage of actual organ donors that express 1 or more of these unacceptable antigens. We developed a CPRA calculator based on the HLA frequencies in Koreans to measure sensitization levels in Korean patients.
  
  
  METHODS
  To develop the calculator, we obtained the HLA-A, HLA-B, and HLA-DR phenotypes of 1,622 Koreans, and compared these with previously reported frequencies in Koreans. Sera from patients awaiting kidney transplantation were tested for HLA antibodies by Luminex PRA-screen, PRA-identification (ID), and PRA-SA assays. The measured %PRA from the PRA-screen (N=55) and PRA-ID (N=71) were compared to the %CPRA for the unacceptable antigens obtained from PRA-SA.
  
  
  RESULTS
  Phenotype frequencies used for the CPRA calculator agreed with previously reported data. The concordance rates among the 3 PRA methods for the detection of class I and class II antibodies were 76.1-81.8% (kappa, 0.519-0.636) and 72.7-83.6% (0.463-0.650), respectively. For the detection of broadly sensitized sera (>50% or >80%), the concordance rates were over 80%. In sera with 80-100% CPRA, 91.7% and 94.4% of the samples had concordant results (80-100% PRA) in the PRA-screen and PRA-ID assay, respectively.
  
  
  CONCLUSIONS
  Although further clinical studies are required to confirm the benefits of CPRA values, adoption of CPRA analysis based on HLA frequencies in Koreans may be useful for sensitization measurements and organ-allocation algorithms.
authors.affiliation: Department of Laboratory Medicine, School of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Jang
authors.forename: Yoon-Joo
authors.initials: YJ
authors.lastname: Kim
authors.forename: Yonggoo
authors.initials: Y
authors.lastname: Kim
authors.forename: Yeon-Joon
authors.initials: YJ
authors.lastname: Park
authors.forename: Kyungja
authors.initials: K
authors.lastname: Han
authors.forename: Eun-Jee
authors.initials: EJ
authors.lastname: Oh
mesh_terms: D000465:Algorithms; D006680:HLA Antigens / Q000276:immunology; D015235:HLA-B Antigens / Q000276:immunology; D006684:HLA-DR Antigens / Q000276:immunology; D006650:Histocompatibility Testing; D006801:Humans; D007518:Isoantibodies / Q000097:blood* / Q000276:immunology; D010641:Phenotype; D056910:Republic of Korea
chemical_list: D006680:HLA Antigens; D015235:HLA-B Antigens; D006684:HLA-DR Antigens; D007518:Isoantibodies