title: Flow Cytometric Panel-Reactive Antibody Results and the Ability to Find Transfusion-Compatible Platelets after Antibody-Desensitization for Allogeneic Bone Marrow Transplant.
abstract: BACKGROUND
  Panel reactive antibody (PRA) reduction protocols are used to decrease anti-HLA antibodies with concomitant PRA monitoring as a measure of successful treatment prior to organ and haploidentical blood and marrow transplant (BMT). We hypothesized that the more sensitive flow cytometry (FC) based assays for PRA [FlowPRA®and Luminex®based Single Antigen Bead (SAB)] would also correlate with the ability to find compatible platelets for allosensitized recipients.
  
  
  METHODS
  A female patient with myelodysplastic syndrome and a high HLA class I PRA [>90% PRA and cPRA by complement-dependent cytotoxicity (CDC) assay and Flow PRA] required allogeneic BMT. Baseline HLA Class I and class II antigen typing was performed and a matched sibling donor was identified. Although baseline anti-HLA class I and class II antibodies measured by FC and CDC revealed no donor specific antibodies (DSA), the decision was made to attempt antibody desensitization to facilitate platelet transfusion during BMT. FC and CDC assays were performed to determine anti-HLA class I antibodies and cPRA/%PRA prior to starting desensitization and at the end of desensitization. Over the course of desensitization and BMT, a total of 194 apheresis platelet units underwent cross-match (XM) using Capture-P®. We compared temporally-related PRA results with platelet XM results.
  
  
  RESULTS
  High PRA by FC or CDC assays correlates with a high % of XM-positive (incompatible) platelet units. When the CDC PRA fell to 2% after desensitization, platelet XM incompatibility fell from 100% to 63% positive (incompatible). When the FC PRA fell to 5% the positive platelet XM fell to 5%.
  
  
  CONCLUSIONS
  Antibody desensitization facilitated platelet transfusion. PRA determination by FC appeared better correlated than determination by CDC with the ability to find XM-compatible platelets.
authors.affiliation: Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Rosenbaum
authors.affiliation: Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Soumya
authors.initials: S
authors.lastname: Pandey
authors.affiliation: Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Terry O
authors.initials: TO
authors.lastname: Harville
authors.affiliation: Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Gina A
authors.initials: GA
authors.lastname: Drobena
authors.affiliation: Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA foxmicheleh@uams.edu.
authors.forename: Michele
authors.initials: M
authors.lastname: Cottler-Fox
mesh_terms: D000906:Antibodies / Q000276:immunology*; D001792:Blood Platelets / Q000276:immunology*; D001803:Blood Transfusion; D016026:Bone Marrow Transplantation; D003601:Cytotoxicity Tests, Immunologic; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D014184:Transplantation, Homologous
chemical_list: D000906:Antibodies
keywords: PRA; antibody desensitization; complement dependent cell cytotoxicity; flow cytometry; platelet cross-matching