title: T cell subsets in human airways prior to and following endobronchial administration of endotoxin.
abstract: OBJECTIVE
  Bronchial instillation of lipopolysaccharide (LPS) provides a reversible model of lung inflammation that may resemble early stages of acute respiratory distress syndrome (ARDS). We investigated the distributions of T-cell subsets in the human airways and sought to determine whether pro- and anti-inflammatory T cells are involved in the local immune response to lung inflammation.
  
  
  METHODS
  Bronchoalveolar lavage (BAL) was performed in 15 healthy volunteers, after which Escherichia coli LPS (4 ng/kg) was administered. BAL was repeated at 2, 4, 6, 8 or 24 h after instillation of LPS.
  
  
  RESULTS
  BALF CD4+ and CD8+ T cells were characterized by expression of activation markers (HLA-DR+CD38+), the proportion of cells expressing naïve markers (CD45RA+CD27+CCR7+) was lower, and that of cells expressing effector memory markers (CD45RA-CD27+CCR7-) was higher, compared with peripheral blood. Bronchial LPS induced a local inflammatory response with recruitment of CD4+ (P=0.014), CD8+ T cells (P=0.034), an increase in the proportion of CD4+CD25+CD127lowFoxp3+ regulatory T cells (Tregs) (P=0.045) and a tendency towards an increase in CD4+CD161+ cells (P=0.071) were observed.
  
  
  CONCLUSIONS
  A unique distribution of T cells with little day-to-day variation was found in human airways. An increase in Tregs after endobronchial LPS suggests a role for Tregs during early stages of pulmonary inflammation.
authors.affiliation: Viro-immunology Research Unit, Department of Infectious Diseases 8632, University Hospital Rigshospitalet, Copenhagen, Denmark; Department of Clinical Immunology 2034, Blood Bank, University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Andreas
authors.initials: A
authors.lastname: Ronit
authors.forename: Ronni R
authors.initials: RR
authors.lastname: Plovsing
authors.forename: Julie C
authors.initials: JC
authors.lastname: Gaardbo
authors.forename: Ronan M G
authors.initials: RM
authors.lastname: Berg
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Hartling
authors.forename: Lars
authors.initials: L
authors.lastname: Konge
authors.forename: Martin
authors.initials: M
authors.lastname: Iversen
authors.forename: Henrik
authors.initials: H
authors.lastname: Ullum
authors.forename: Kirsten
authors.initials: K
authors.lastname: Møller
authors.forename: Susanne Dam
authors.initials: SD
authors.lastname: Nielsen
mesh_terms: D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D004731:Endotoxins; D005434:Flow Cytometry; D006801:Humans; D008070:Lipopolysaccharides / Q000506:poisoning; D018655:Lymphocyte Count; D008297:Male; D011014:Pneumonia / Q000139:chemically induced / Q000276:immunology*; D012128:Respiratory Distress Syndrome / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D055815:Young Adult
chemical_list: D004731:Endotoxins; D008070:Lipopolysaccharides
keywords: Escherichia coli lipopolysaccharide; bronchoalveolar lavage fluid; pulmonary inflammation; regulatory T cells