title: Immune modulation after total hip surgery. A prospective ex vivo study.
abstract: BACKGROUND
  Major trauma affects the immune system, and immunosuppression may render the patients susceptible to septic complications. The purpose of this study was to investigate lipopolysaccharide (LPS)-induced releases of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in whole blood in patients undergoing total hip replacement.
  
  
  METHODS
  Seven patients (6 females) who underwent elective total hip replacement were included. Ex vivo LPS-induced releases of TNF-alpha and IL-6 were measured in a whole blood assay at days 1, 6, 9 and 12 postoperatively, using low- and high-dose LPS incubation. At the same time, white blood cell counts were analyzed.
  
  
  RESULTS
  The amount of TNF-alpha release was significantly reduced at days 6 and 12. Compared to monocyte counts, TNF-alpha release was significantly decreased also at day 9 in low- and high-dose LPS stimulation. IL-6 in plasma was significantly increased at day 1 and normalized thereafter. There were no differences in LPS-induced IL-6 levels compared to the levels before surgery.
  
  
  CONCLUSIONS
  This in vivo/ex vivo study shows a reduced capacity of whole blood to release LPS-induced TNF-alpha at day 6 through to day 12 after major orthopedic surgery. Attenuated TNF-alpha release may contribute to an increased postoperative susceptibility to gram-negative sepsis.
authors.affiliation: Department of Orthopaedics, Rikshospitalet Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway.
authors.forename: D
authors.initials: D
authors.lastname: Bastian
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.forename: C
authors.initials: C
authors.lastname: Danckert Krohn
authors.forename: O
authors.initials: O
authors.lastname: Reikerås
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000502:physiology*; D015850:Interleukin-6 / Q000097:blood*; D007958:Leukocyte Count; D008070:Lipopolysaccharides; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood*
chemical_list: D015850:Interleukin-6; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha