title: T-cell phenotypes in bronchoalveolar lavage fluid, blood and lymph nodes in pulmonary sarcoidosis--indication for an airborne antigen as the triggering factor in sarcoidosis.
abstract: BACKGROUND
  An increased percentage of CD4+ T cells is usually observed in bronchoalveolar lavage fluid (BALF) from patients with sarcoidosis. In HLA-DRB1*03-positive patients, such T cells express the T-cell receptor (TCR) AV2S3+ gene segment. It is not known whether cells found in BALF reflect those in enlarged regional lymph nodes (LNs). Therefore, the aim of this study was to compare T-cell phenotypes in BALF, blood and mediastinal LNs.
  
  
  METHODS
  Fifteen patients underwent clinical investigation including bronchoscopy with bronchoalveolar lavage. Blood samples were drawn, and endoscopic ultrasound-guided fine-needle aspiration of enlarged mediastinal LNs was performed via the oesophagus. T cells from all three compartments were analysed by flow cytometry for markers of activity, differentiation and T regulatory function.
  
  
  RESULTS
  The CD4/CD8 ratio was significantly higher in BALF compared with regional LNs and was also significantly higher in LNs than in blood. The CD4+ T cells were recently activated and more differentiated in BALF than in blood and LNs. There was an accumulation of T regulatory cells (FOXP3+) in LNs and a correlation between high levels of FOXP3+ cells in BALF and in LNs. In HLA-DRB1*03-positive patients, TCR AV2S3+ CD4+ T cells were predominantly localized within BALF.
  
  
  CONCLUSIONS
  The CD4+ T-cell phenotype in BALF indicates an active ongoing specific immune response primarily localized to the alveolar space.
authors.affiliation: Department of Medicine, Respiratory Medicine Unit, Södersjukhuset, Sweden. pernilla.darlington@ki.se
authors.forename: P
authors.initials: P
authors.lastname: Darlington
authors.forename: H
authors.initials: H
authors.lastname: Haugom-Olsen
authors.forename: K
authors.initials: K
authors.lastname: von Sivers
authors.forename: J
authors.initials: J
authors.lastname: Wahlström
authors.forename: M
authors.initials: M
authors.lastname: Runold
authors.forename: V
authors.initials: V
authors.lastname: Svjatoha
authors.forename: A
authors.initials: A
authors.lastname: Porwit
authors.forename: A
authors.initials: A
authors.lastname: Eklund
authors.forename: J
authors.initials: J
authors.lastname: Grunewald
mesh_terms: D000328:Adult; D000368:Aged; D000941:Antigens / Q000235:genetics / Q000276:immunology; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology*; D001999:Bronchoscopy / Q000379:methods; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D008198:Lymph Nodes / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology*; D017565:Sarcoidosis, Pulmonary / Q000235:genetics / Q000276:immunology*; D013223:Statistics as Topic
chemical_list: D000941:Antigens; D011948:Receptors, Antigen, T-Cell