title: Incidence of transfusion-induced platelet-reactive antibodies evaluated by specific assays for the detection of human leucocyte antigen and human platelet antigen antibodies.
abstract: OBJECTIVE
  The aim of this work was to study the incidence of transfusion-induced platelet-reactive antibodies in a selective patient population and evaluate different methodologies for platelet antibody screening (PAS).
  
  
  METHODS
  The patients were retrospectively selected and divided into three separate groups: haematological malignancies (Group 1: n = 33); cardiac and orthopaedic patients (Group 2: n = 31) and a control group (Group 3: n = 23) selected with the same diagnoses of Group 2. PRE- and POST-transfusion samples were tested for PAS by the following tests: PIFT (platelet immunofluorescence test), MAIPA (monoclonal antibody immobilization of platelet antigen), Flow PRA(R) and LCT (lymphocytotoxicity test).
  
  
  RESULTS
  There was not a 100% concordance among the methodologies used. PIFT, MAIPA and Flow PRA presented very similar results whereas that of LCT differed from the other methods. A high rate of positive results (32%) was found in the PRE samples followed by an increase of almost 50% after blood transfusion (POST samples: 42.5% of positivity), but there was a statistical difference (P < 0.05) between the PRE and POST transfusion sample only for the Flow PRA(R) technique tested on Group 2. Human leucocyte antigen (HLA) class I antibodies were present on 97.4% of POST positive samples, 5.4% presented anti-human platelet antigen (HPA)-1b antibodies and 8.1% presented a mix of pan-reactive antibodies against glycoprotein IIbIIIa, IaIIa and IbIX.
  
  
  CONCLUSIONS
  Blood transfusion did not increase the rate of alloimmunization in our haematological patients (Group 1); however, the patients were already admitted with a high rate of alloimmunization (12%). Group 2 patients are being immunized and the impact of this procedure remains to be studied as these patients may eventually undergo further hospitalization and receive more blood transfusion.
authors.affiliation: Banco de Sangue, Hospital Sírio Libanês, São Paulo, SP, Brazil. rswendel@uninet.com.br
authors.forename: R
authors.initials: R
authors.lastname: Fontão-Wendel
authors.forename: L C N
authors.initials: LC
authors.lastname: Silva
authors.forename: C B R
authors.initials: CB
authors.lastname: Saviolo
authors.forename: B
authors.initials: B
authors.lastname: Primavera
authors.forename: S
authors.initials: S
authors.lastname: Wendel
mesh_terms: D000368:Aged; D016824:Antigens, Human Platelet / Q000276:immunology*; D005260:Female; D006680:HLA Antigens / Q000276:immunology*; D006801:Humans; D007518:Isoantibodies / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D065227:Transfusion Reaction
chemical_list: D016824:Antigens, Human Platelet; D006680:HLA Antigens; D007518:Isoantibodies