title: HLA-DR expression on monocytes is decreased in polytraumatized patients.
abstract: BACKGROUND
  Sepsis, systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) remain the most frequent causes of complications and death in severely injured patients. A main reason for the development of these syndromes is a post-traumatic dysregulation of the immune system. Several studies in intensive care unit (ICU) patients could detect a pivotal role of HLA-DR expression on monocytes. So far, its importance for development of SIRS, sepsis or MODS in the severely injured patient is not clear.
  
  
  METHODS
  Therefore, we have analysed HLA-DR expression on monocytes from severely injured patients (ISS > 16) during the post-traumatic course, which was on the day of trauma, as well as on days 3, 7 and 14 post trauma. Clinical data were analysed and the HLA-DR expression levels of patients who developed post-traumatic sepsis, SIRS or MODS were compared to those with a more favourable outcome. Young and healthy volunteers as well as patients undergoing prosthetic hip replacement after trauma were enrolled as control groups. HLA-DR molecules on monocytes were marked with PE-conjugated antibodies and the mean fluorescence intensity (MFI) was analysed via flow cytometry.
  
  
  RESULTS
  24 severely injured patients (mean age 34 ± 2.7 years) mainly after high energy motor vehicle accidents as well as 8 controls (total hip replacement) and 9 healthy volunteers (mean age 26.2 ± 1.2 years) were enrolled. A total of eight patients suffered from sepsis (33.3 %) (six males, two females) and 17 patients suffered from SIRS (70.9 %) (10 males, 7 females). MODS was present in five patients (20.8 %), three male and two female patients. In four of these five patients the MODS developed subsequent to sepsis. HLA-DR expression significantly decreased after trauma and slowly returned to normal after 14 days, irrespective of the complications developed.
  
  
  CONCLUSIONS
  In conclusion, post-traumatic HLA-DR expression on monocytes is significantly reduced after multiple trauma and it is back to normal on day 14. No significant changes in HLA-DR expression on monocytes from severely injured patients suffering from SIRS, MODS or sepsis compared to those who did not have complications could be detected. Nevertheless, HLA-DR expression on monocytes may be used to identify the immunological pro- or anti-inflammatory phase the patient is going through.
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University Munich, Ismaninger Strasse 22, 81675, Munich, Germany. h.vester@tum.de.
authors.forename: Helen
authors.initials: H
authors.lastname: Vester
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University Munich, Ismaninger Strasse 22, 81675, Munich, Germany. h.vester@tum.de.
authors.forename: P
authors.initials: P
authors.lastname: Dargatz
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University Munich, Ismaninger Strasse 22, 81675, Munich, Germany. Stefan.Huber-Wagner@mri.tum.de.
authors.forename: S
authors.initials: S
authors.lastname: Huber-Wagner
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University Munich, Ismaninger Strasse 22, 81675, Munich, Germany. Peter.Biberthaler@mri.tum.de.
authors.forename: P
authors.initials: P
authors.lastname: Biberthaler
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University Munich, Ismaninger Strasse 22, 81675, Munich, Germany. martijn.vangriensven@tum.de.
authors.forename: M
authors.initials: M
authors.lastname: van Griensven
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006684:HLA-DR Antigens / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology*; D009104:Multiple Trauma / Q000276:immunology*; D014949:Wounds, Nonpenetrating / Q000276:immunology; D055815:Young Adult
chemical_list: D006684:HLA-DR Antigens