title: Blood transfusion is associated with donor leukocyte microchimerism in trauma patients.
abstract: BACKGROUND
  Blood transfusion can result in survival of donor leukocyte subpopulations in the recipient. Persistence of donor leukocytes in the transfusion recipient is termed microchimerism. Microchimerism likely reflects engraftment of the recipient with donor hematopoietic stem cells and is very uncommon with transfusion for elective surgery, sickle cell anemia, thalassemia, and HIV. We have found, however, that microchimerism may be more common in trauma patients.
  
  
  OBJECTIVE
  To determine how frequently transfusion after trauma is associated with microchimerism.
  
  
  METHODS
  We prospectively enrolled 45 trauma patients who were transfused > or =2 units of PRBCs. We sampled blood before hospital discharge and determined microchimerism by polymerase chain reaction (PCR) analysis of specimens using quantitative allele-specific HLA DR assays to detect non-recipient alleles. Data are expressed as median with interquartile range.
  
  
  RESULTS
  Patients had a median age of 38 (interquartile range 25, 58) years, ISS of 19 (13, 29), and mortality of 7%. Seventy-eight percent were men, and 84% had blunt trauma. Patients received a median of 6 (4, 16) (range 2, 87) units of PRBCs. Of the 45 patients, 24 (53%) had evidence of microchimerism. Compared with patients without evidence of microchimerism, these patients had no difference in mean age, gender, ISS, units of PRBCs transfused, time from transfusion to blood sampling, or proportion that underwent splenectomy. Twenty-one of the 24 patients with microchimerism had only 1 or 2 non-recipient DR alleles identified by PCR.
  
  
  CONCLUSIONS
  Transfusion after trauma is associated with over half of recipients having evidence of microchimerism. Age, sex, ISS, and splenectomy of the recipient and the number of transfused units did not correlate with microchimerism. Because the median time from transfusion to sampling for PCR analysis was not longer in the group without microchimerism, it is unlikely microchimerism is due merely to failure of the recipient to clear transfused donor leukocytes.
authors.affiliation: Department of Surgery, University of California, Davis, Medical Center, Blood Centers of the Pacific, San Francisco, California 95817, USA.
authors.forename: Garth H
authors.initials: GH
authors.lastname: Utter
authors.forename: John T
authors.initials: JT
authors.lastname: Owings
authors.forename: Tzong-Hae
authors.initials: TH
authors.lastname: Lee
authors.forename: Teresa G
authors.initials: TG
authors.lastname: Paglieroni
authors.forename: William F
authors.initials: WF
authors.lastname: Reed
authors.forename: Robert C
authors.initials: RC
authors.lastname: Gosselin
authors.forename: Paul V
authors.initials: PV
authors.lastname: Holland
authors.forename: Michael P
authors.initials: MP
authors.lastname: Busch
mesh_terms: D000328:Adult; D000483:Alleles; D001483:Base Sequence; D001782:Blood Donors; D001803:Blood Transfusion / Q000379:methods; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006684:HLA-DR Antigens / Q000235:genetics / Q000276:immunology*; D006801:Humans; D015601:Injury Severity Score; D007962:Leukocytes / Q000276:immunology* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011446:Prospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D018570:Risk Assessment; D065227:Transfusion Reaction; D018183:Transplantation Chimera / Q000235:genetics / Q000276:immunology*; D023001:Transplantation Tolerance / Q000235:genetics / Q000276:immunology; D014193:Trauma Centers; D016896:Treatment Outcome; D014947:Wounds and Injuries / Q000175:diagnosis / Q000628:therapy*
chemical_list: D006684:HLA-DR Antigens