title: Acute intravascular hemolysis after transfusion of a chimeric RBC unit.
abstract: BACKGROUND
  Natural blood cell chimerism rarely occurs in humans. The case of a patient who developed transfusion reaction due to the transfusion of chimeric RBCs is reported.
  
  
  METHODS
  A 61-year-old male patient with blood group O received two units of packed and O-grouped RBCs after elective kidney surgery. Immediately after blood transfusion, the patient developed a hemolytic transfusion attack. The serologic re-examination revealed only a mixed-field pattern of agglutination of RBCs in one of the two transfused units. The donor of this unit was an apparently healthy 24-year-old male with a twin sister. Both of them showed an identical mixture of roughly 95 percent group O and 5 percent group B RBCs by gel agglutination technology and flow cytometry. The results were also confirmed by ABO blood group genotyping.
  
  
  CONCLUSIONS
  This is the first report of a hemolytic transfusion reaction related to the transfusion of chimeric RBCs.
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D002678:Chimera / Q000276:immunology*; D017707:Erythrocyte Transfusion / Q000009:adverse effects*; D006461:Hemolysis; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D000017:ABO Blood-Group System