title: Corticosteroid treatment selectively decreases mast cells in the smooth muscle and epithelium of asthmatic bronchi.
abstract: BACKGROUND
  Mast cells are important in the pathophysiology of airway inflammation and evidence suggests their sub-localisation within the airway is altered in asthma. Little is known about the effect of corticosteroids on mast cell localisation within the bronchi.
  
  
  METHODS
  We therefore performed an immunohistochemical analysis of mast cell numbers within the smooth muscle, epithelium and submucosa of healthy subjects (n = 10) and well-characterised asthmatic patients, using either β(2)-agonists alone (n = 10) or β(2)-agonists and inhaled corticosteroids (n = 10).
  
  
  RESULTS
  Patients using inhaled corticosteroids displayed significantly lower numbers of mast cells within their epithelium and smooth muscle compared to those not treated with inhaled corticosteroids. Submucosal mast cells were not affected by corticosteroid treatment. Numbers of smooth muscle mast cells correlated with bronchial responsiveness and epithelial mast cells with exhaled NO.
  
  
  CONCLUSIONS
  We demonstrate that glucocorticosteroids differentially affect mast cell numbers within specific airway sub-locations highlighting the importance of mast cell and smooth muscle/epithelial interactions in asthma pathogenesis.
authors.affiliation: Experimental Asthma and Allergy Research, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden. anna.james@ki.se
authors.forename: A
authors.initials: A
authors.lastname: James
authors.forename: P
authors.initials: P
authors.lastname: Gyllfors
authors.forename: E
authors.initials: E
authors.lastname: Henriksson
authors.forename: S E
authors.initials: SE
authors.lastname: Dahlén
authors.forename: M
authors.initials: M
authors.lastname: Adner
authors.forename: G
authors.initials: G
authors.lastname: Nilsson
authors.forename: B
authors.initials: B
authors.lastname: Dahlén
mesh_terms: D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000494:pharmacology*; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001249:Asthma / Q000276:immunology* / Q000473:pathology; D001980:Bronchi / Q000276:immunology; D016022:Case-Control Studies; D006801:Humans; D008407:Mast Cells / Q000187:drug effects*; D009130:Muscle, Smooth / Q000276:immunology* / Q000473:pathology; D020545:Respiratory Mucosa / Q000187:drug effects / Q000276:immunology*
chemical_list: D000305:Adrenal Cortex Hormones; D018927:Anti-Asthmatic Agents