title: Bronchoalveolar lavage quality influences the T4/T8 ratio in sarcoidosis.
abstract: BACKGROUND
  Sarcoidosis is characterised by a T-lymphocytic alveolitis with a typically increased T4/T8 ratio. The diagnostic value of this ratio is under debate.
  
  
  OBJECTIVE
  We prospectively evaluated the influence of BAL pre-lavage and the impact of bronchial contamination on BAL differential cell count in 108 BAL specimens obtained from patients with histologically confirmed sarcoidosis.
  
  
  METHODS
  BAL was performed by instilling 150-300 ml normal saline either in the middle lobe or the lingula. Fifty-one patients (47%) underwent additional pre-lavage with 50 ml normal saline. Bronchial contamination was assessed by semi-quantitative analysis of mucus, ciliated and squamous cells in the untreated BAL recovery.
  
  
  RESULTS
  Pre-lavage did neither influence the lavage cellularity nor extend of contamination of the BAL. Content of mucus and ciliated cells, indicating bronchial contamination, showed a high correlation (Kendal's tau=0.61). Presence of either mucus or ciliated cells in the BAL recovery was associated with a significant lower T4/T8 ratio (mucus: 4.9 vs. 8.0, p=0.009; ciliated cells: 4.1 vs. 7.4, p=0.001). Squamous cells in the BAL recovery representing oropharyngeal contamination did not significantly influence the T4/T8 ratio (7.7 vs. 5.6, p=0.10).
  
  
  CONCLUSIONS
  Bronchial contamination of BAL as determined by the presence of mucus and ciliated cells in the recovery decreases the T4/T8 ratio of BAL in sarcoidosis.
authors.affiliation: Pulmonary Medicine, University Hospital Basel, Switzerland. Frank.Reichenberger@innere.med.uni-giessen.de
authors.forename: Frank
authors.initials: F
authors.lastname: Reichenberger
authors.forename: Brigitte
authors.initials: B
authors.lastname: Kleiber
authors.forename: Betty
authors.initials: B
authors.lastname: Baschiera
authors.forename: Lukas
authors.initials: L
authors.lastname: Bubendorf
authors.forename: Martin
authors.initials: M
authors.lastname: Brutsche
authors.forename: Peter
authors.initials: P
authors.lastname: Dalquen
authors.forename: Michael
authors.initials: M
authors.lastname: Tamm
mesh_terms: D018893:Bronchoalveolar Lavage / Q000379:methods; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology*; D016516:CD4-CD8 Ratio; D002452:Cell Count; D002923:Cilia / Q000473:pathology; D005260:Female; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D009093:Mucus / Q000166:cytology; D011446:Prospective Studies; D017565:Sarcoidosis, Pulmonary / Q000276:immunology* / Q000473:pathology; D012965:Sodium Chloride; D013048:Specimen Handling / Q000379:methods; D016176:T-Lymphocyte Subsets / Q000276:immunology*
chemical_list: D012965:Sodium Chloride