title: A bead-based assay in the work-up of suspected platelet alloimmunization.
abstract: BACKGROUND
  Alloantibodies against human platelet antigens (HPAs) are of clinical significance in immune-mediated thrombocytopenia such as fetal/neonatal alloimmune thrombocytopenia (FNAIT), posttransfusion purpura, and platelet (PLT) transfusion refractoriness. The gold standard for the detection of these antibodies is the monoclonal antibody immobilization of PLT antigens (MAIPA) assay. Both requirement of typed donor PLT panels and technical expertise often restrict its use to reference laboratories.
  
  
  METHODS
  An easy-to-use, bead-based assay (BBA) has been introduced recently. In this study, we compared MAIPA and BBA test results for 126 serum samples from women who gave birth to a child with FNAIT including rare HPA specificities (n = 111) and from patients with PLT transfusion refractoriness (n = 15).
  
  
  RESULTS
  For sera with defined allospecificities, the number of BBA false-negatives was 12 of 126, or 9.5%, and the number of BBA false-positives (i.e., detection of additional specificities) was two of 126, or 1.6%. BBA had major problems in detecting antibodies against HPA-3a (3/15 undetected = 20% failure rate) and HPA-3b (5/6 undetected = 83.3% failure rate), but performed well in detecting typical FNAIT- or PLT transfusion refractoriness-associated antibodies including HPA-1a (35/35 = 100%), HPA-1b (15/15 = 100%), HPA-5b (22/24 = 91.6%), and glycoprotein IV (6/6 = 100%).
  
  
  CONCLUSIONS
  BBA might be a useful and time-saving tool in the initial laboratory work-up of suspected PLT alloimmunization when an appropriate algorithm ensures follow-up investigation of BBA-negative sera.
authors.affiliation: Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University.
authors.forename: Nina
authors.initials: N
authors.lastname: Cooper
authors.affiliation: Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University.|German Center for Fetomaternal Incompatibility (DZFI), University Hospital Giessen and Marburg, Giessen, Germany.
authors.forename: Gregor
authors.initials: G
authors.lastname: Bein
authors.affiliation: Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Heidinger
authors.affiliation: Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University.
authors.forename: Sentot
authors.initials: S
authors.lastname: Santoso
authors.affiliation: Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University.|German Center for Fetomaternal Incompatibility (DZFI), University Hospital Giessen and Marburg, Giessen, Germany.
authors.forename: Ulrich J
authors.initials: UJ
authors.lastname: Sachs
mesh_terms: D016824:Antigens, Human Platelet / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007159:Immunologic Tests / Q000295:instrumentation / Q000379:methods*; D007518:Isoantibodies / Q000097:blood*; D008297:Male; D017713:Platelet Transfusion; D054098:Thrombocytopenia, Neonatal Alloimmune / Q000276:immunology; D065227:Transfusion Reaction / Q000276:immunology / Q000517:prevention & control
chemical_list: D016824:Antigens, Human Platelet; D015415:Biomarkers; D007518:Isoantibodies