title: Decrease of CD4-lymphocytes and apoptosis of CD14-monocytes are characteristic alterations in sepsis caused by ventilator-associated pneumonia: results from an observational study.
abstract: BACKGROUND
  The present study aimed to investigate changes of the immune response between sepsis due to ventilator-associated pneumonia (VAP) and sepsis due to other types of infections.
  
  
  METHODS
  Peripheral venous blood was sampled from 68 patients with sepsis within 24 hours of diagnosis; 36 suffered from VAP; 32 from other nosocomial infections, all well-matched for severity, age and sex. Blood monocytes were isolated and cultured with/without purified endotoxin (lipopolysaccharide (LPS)). Estimation of tumour necrosis factor alpha (TNFalpha) and interleukin-6 (IL-6) in cultures' supernatants was done by an enzyme immunoassay. Flow cytometry was used to determine subpopulations of mononuclear cells and apoptosis. To mimic pathogenesis of VAP, mononuclear cells of healthy volunteers were progressively stimulated with increased inocula of pathogens; apoptosis was determined.
  
  
  RESULTS
  In patients with VAP, the absolute number of CD3(+)/CD4(+) lymphocytes was significantly lower (P = 0.034) and apoptosis of isolated monocytes was increased (P = 0.007) compared to other infections. TNFalpha and IL-6 production from LPS-stimulated monocytes was lower in patients with VAP-related sepsis than with sepsis due to other infections. Apoptosis of monocytes was induced after in vitro stimulation of mononuclear cells by a mechanism mimicking VAP.
  
  
  CONCLUSIONS
  Decrease of CD4-lymphocytes and immunoparalysis of monocytes are characteristic alterations of sepsis arising in the field of VAP.
authors.affiliation: 4th Department of Internal Medicine, ATTIKON University Hospital, 1 Rimini Str, Athens 124 62, Greece. aimpelekanou@yahoo.gr
authors.forename: Aimilia
authors.initials: A
authors.lastname: Pelekanou
authors.forename: Iraklis
authors.initials: I
authors.lastname: Tsangaris
authors.forename: Antigoni
authors.initials: A
authors.lastname: Kotsaki
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Karagianni
authors.forename: Helen
authors.initials: H
authors.lastname: Giamarellou
authors.forename: Apostolos
authors.initials: A
authors.lastname: Armaganidis
authors.forename: Evangelos J
authors.initials: EJ
authors.lastname: Giamarellos-Bourboulis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000276:immunology; D017209:Apoptosis; D001424:Bacterial Infections / Q000150:complications / Q000276:immunology; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D003428:Cross Infection / Q000150:complications / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000276:immunology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000276:immunology*; D053717:Pneumonia, Ventilator-Associated / Q000150:complications / Q000276:immunology*; D018805:Sepsis / Q000097:blood / Q000209:etiology / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides