title: Agreement among HLA antibody detection assays is higher in ever-pregnant donors and improved using a consensus cutoff.
abstract: BACKGROUND
  HLA antibodies might contribute to the pathogenesis of transfusion-related acute lung injury (TRALI). HLA antibody detection methods include ELISA, flow cytometry, and multiplex bead-based assays, as well as the older lymphocytotoxicity assay, and it is not obvious how to compare results across platforms.
  
  
  METHODS
  Five hundred twenty-five serum samples were selected from 7841 donors in the Leukocyte Antibody Prevalence Study (LAPS) repository based on risk for the development of HLA antibodies, using the number of pregnancies as the risk factor. Subjects included 81 males and females with 0 (n = 187), 1 (n = 67), or 2+ pregnancies (n = 190). Replicate frozen serum aliquots were sent blinded to four different HLA antibody assay manufacturers for detection using five different assays.
  
  
  RESULTS
  The flow cytometry and multiplex bead based-assays typically resulted in a larger proportion of HLA antibody positive samples compared with ELISA based assays. Latent variable analysis was used to derive a new set of consensus cutoffs, which yielded similar sensitivities across test platforms and increased concordance amongst assays. Assay agreement was higher in ever pregnant females than in males and never-pregnant females.
  
  
  CONCLUSIONS
  Different assays resulted in varied positivity rates when the manufacturer's suggested cutoffs were used, demonstrating that care needs to be taken when comparing clinical outcomes data generated using different HLA antibody assays and testing platforms. The method used here, involving latent variable analysis, presents one possible approach to calculating comparable cutoffs that result in broad agreement across assays with respect to positivity designation.
authors.affiliation: Blood Systems Research Institute and Blood Centers of the Pacific, San Francisco, California 94118, USA.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Carrick
authors.forename: Bryce
authors.initials: B
authors.lastname: Johnson
authors.forename: Steven H
authors.initials: SH
authors.lastname: Kleinman
authors.forename: Robert
authors.initials: R
authors.lastname: Vorhaben
authors.forename: Suzette C
authors.initials: SC
authors.lastname: Chance
authors.forename: Jar-How
authors.initials: JH
authors.lastname: Lee
authors.forename: John D
authors.initials: JD
authors.lastname: Roback
authors.forename: Suchitra
authors.initials: S
authors.lastname: Pandey
authors.forename: Yu
authors.initials: Y
authors.lastname: Sun
authors.forename: Michael P
authors.initials: MP
authors.lastname: Busch
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Norris
mesh_terms: D055371:Acute Lung Injury / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control; D000906:Antibodies / Q000097:blood*; D001782:Blood Donors / Q000706:statistics & numerical data*; D032921:Consensus; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data; D005260:Female; D005434:Flow Cytometry / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D007962:Leukocytes / Q000276:immunology; D008297:Male; D015233:Models, Statistical; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D065227:Transfusion Reaction
chemical_list: D000906:Antibodies; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II