title: Differential airway inflammatory responses in asthma exacerbations induced by respiratory syncytial virus and influenza virus a.
abstract: BACKGROUND
  Although respiratory viral infections cause acute exacerbations of asthma, the inflammatory responses vary depending on the causative virus. The purpose of this study was to compare the inflammatory responses in the airways of acute exacerbations of asthma induced by respiratory syncytial virus (RSV) and influenza A virus.
  
  
  METHODS
  Sputum induction was performed in asthmatic patients with acute exacerbations induced by RSV (n = 6), influenza A (n = 7), and non-upper respiratory infection (URI)-related factors (n = 8). Sputum concentrations of cysteinyl leukotrienes (cysLTs), TNF-α and IFN-γ were measured.
  
  
  RESULTS
  Sputum cysLTs were significantly higher in RSV-induced exacerbations than in influenza A- and non-URI-induced exacerbations. Sputum TNF-α was significantly higher in influenza A-induced exacerbations than in RSV- and non-URI-induced exacerbations. Sputum IFN-γ was significantly lower in RSV-induced exacerbations than in the others.
  
  
  CONCLUSIONS
  RSV and influenza A cause acute exacerbations and have different effects on airway inflammation in asthmatic patients. RSV significantly increased cysLTs, while influenza A significantly increased TNF-α in the airway. The underlying mechanism in virus-induced asthma might depend on the viral species.
authors.affiliation: Second Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan. hmatsuse@nagasaki-u.ac.jp
authors.forename: Hiroto
authors.initials: H
authors.lastname: Matsuse
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tsuchida
authors.forename: Susumu
authors.initials: S
authors.lastname: Fukahori
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kawano
authors.forename: Shinya
authors.initials: S
authors.lastname: Tomari
authors.forename: Nobuko
authors.initials: N
authors.lastname: Matsuo
authors.forename: Tomoya
authors.initials: T
authors.lastname: Nishino
authors.forename: Chizu
authors.initials: C
authors.lastname: Fukushima
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kohno
mesh_terms: D000328:Adult; D001249:Asthma / Q000150:complications / Q000276:immunology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000276:immunology* / Q000472:pathogenicity; D007251:Influenza, Human / Q000150:complications / Q000276:immunology*; D007371:Interferon-gamma / Q000378:metabolism; D017998:Leukotriene D4 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018357:Respiratory Syncytial Virus Infections / Q000150:complications / Q000276:immunology*; D012136:Respiratory Syncytial Viruses / Q000276:immunology* / Q000472:pathogenicity; D013183:Sputum / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D014409:Tumor Necrosis Factor-alpha; D017998:Leukotriene D4; D007371:Interferon-gamma