title: Influence of smoking on airway inflammation and remodelling in asthma.
abstract: BACKGROUND
  Although exposure to tobacco smoke has been associated with increased morbidity and mortality, cigarette smoking is still common in the asthmatic population. Induced sputum neutrophilia has been observed in asthmatic smokers, but the effects of regular smoking on their bronchial mucosa morphology remain to be defined. This study documents the inflammatory and remodelling features in bronchial biopsies of smoking compared with non-smoking asthmatics.
  
  
  METHODS
  We analysed bronchial biopsies from 24 steroid-naïve young subjects with mild asthma: 12 non-smoking and 12 currently smoking subjects. In addition to airway morphology assessment, inflammation and remodelling were analysed by immunohistochemistry using antibodies against CD3, CD68, major basic protein, neutrophil elastase, and tryptase. Expression of the cytokines IL-4, IL-5, IL-8, IFN-gamma, transforming growth factor-beta, and TNF was determined by in situ hybridization.
  
  
  RESULTS
  Compared with non-smoking asthmatic subjects, smoking asthmatics' bronchial mucosa showed squamous cell metaplasia, in addition to increased expression of subepithelial neutrophil elastase, IFN-gamma, and intraepithelial IL-8.
  
  
  CONCLUSIONS
  Smoking status modifies morphological and inflammatory processes in young subjects with mild asthma. The changes may possibly affect asthma treatment responses and clinical outcomes.
authors.affiliation: Unité de recherche en pneumologie et, Hôpital Laval, Institut Universitaire de Cardiologie et de Pneumologie de l'Université Laval, Québec, QC, Canada.
authors.forename: J
authors.initials: J
authors.lastname: St-Laurent
authors.forename: C
authors.initials: C
authors.lastname: Bergeron
authors.forename: N
authors.initials: N
authors.lastname: Pagé
authors.forename: C
authors.initials: C
authors.lastname: Couture
authors.forename: M
authors.initials: M
authors.lastname: Laviolette
authors.forename: L-P
authors.initials: LP
authors.lastname: Boulet
mesh_terms: D000328:Adult; D001249:Asthma / Q000276:immunology* / Q000473:pathology; D001991:Bronchitis / Q000276:immunology* / Q000473:pathology; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology*; D004847:Epithelial Cells / Q000166:cytology / Q000276:immunology / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D020545:Respiratory Mucosa / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D012907:Smoking / Q000009:adverse effects* / Q000276:immunology
chemical_list: D016207:Cytokines