title: Acute and delayed hemolytic transfusion reactions secondary to HLA alloimmunization.
abstract: BACKGROUND
  HLA antibodies may be directed against HLA antigens on RBCs, but these antibodies are generally not considered to be clinically significant in transfusion practice. A case of a multiparous woman who had hemolytic transfusion reactions due to HLA-related Bg antibodies is reported.
  
  
  METHODS
  A 37-year-old woman was admitted with anemia. No unexpected RBC antibodies were identified. Two group O, D+ RBC units were transfused. Ten days later she returned with hemolysis and anemia. Two more RBC units were ordered, no unexpected RBC antibodies were identified, and two crossmatch-compatible units were issued. During the transfusion, the patient developed symptoms of an acute reaction, and the posttransfusion sample showed evidence of intravascular hemolysis.
  
  
  RESULTS
  Repeat RBC antibody screen showed anti-Bg. HLA antibody screen identified anti-HLA-A2, A28, B7, B7 cross-reactive group (CREG). The two RBC units from the first transfusion episode and one RBC unit from the second transfusion episode were HLA incompatible with the patient. No other cause for the hemolytic reactions was identified. The patient was later successfully transfused with one RBC unit from an HLA-compatible donor.
  
  
  CONCLUSIONS
  HLA antibodies should be considered in patients with hemolytic transfusion reactions when RBC-specific antibodies are not found to be the etiology.
authors.affiliation: Department of Interdisciplinary Oncology, University of South Florida College of MedicineTampa, Florida, USA. benson@moffitt.usf.edu
authors.forename: Kaaron
authors.initials: K
authors.lastname: Benson
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Agosti
authors.forename: Gerardo E
authors.initials: GE
authors.lastname: Latoni-Benedetti
authors.forename: German F
authors.initials: GF
authors.lastname: Leparc
mesh_terms: D000328:Adult; D005260:Female; D006680:HLA Antigens / Q000276:immunology*; D006461:Hemolysis; D006650:Histocompatibility Testing; D006801:Humans; D007518:Isoantibodies / Q000276:immunology*; D065227:Transfusion Reaction
chemical_list: D006680:HLA Antigens; D007518:Isoantibodies