title: Predictors of neutrophilic airway inflammation in young smokers with asthma.
abstract: BACKGROUND
  Asthma is one of the most widespread chronic diseases worldwide. In spite of numerous detrimental effects on asthma, smoking is common among asthma patients. These smoking-induced aggravations of asthma may be attributed to changes in airway inflammation, which is characterized by a higher degree of neutrophilic inflammation than in non-smokers. A state of neutrophilic inflammation may lead to increased steroid resistance and an accelerated loss of lung function owing to tissue destruction. The aim of this study was to elucidate predictors of neutrophilic inflammation in young asthmatic smokers not on steroid treatment, including analysis of tobacco history and bacterial colonization.
  
  
  METHODS
  In a cross-sectional study, 52 steroid-free, current smokers with asthma were examined with induced sputum, fractional exhaled nitric oxide (FeNO), lung function, ACQ6 score, mannitol and methacholine challenge. A sample from the sputum induction was taken for bacterial analysis using 16S gene PCR technique and sequencing.
  
  
  RESULTS
  Using one-way analysis of variance and binary and linear regression models, only age and ACQ6 score were found to be significant predictors for airway neutrophilia. The investigation also included analysis for effect of pack years, current tobacco consumption, body mass index, lung function, FeNO; methacholine and mannitol responsiveness, atopy, gender, asthma history and presence of bacteria. The most common potentially pathogenic bacteria found were Streptococcus spp., Haemophilus spp. and Mycoplasma spp.
  
  
  CONCLUSIONS
  In this study, no tobacco-related predictors of airway neutrophilia were found, indicating that in the younger years of asthma patients who smoke, the amount of tobacco smoked in life does not influence the degree of neutrophilia. Conversely, for asthmatic smokers, neutrophilia may be induced when a certain threshold of tobacco consumption is reached.
authors.affiliation: Respiratory Research Unit, Bispebjerg University Hospital .
authors.forename: Christian Grabow
authors.initials: CG
authors.lastname: Westergaard
authors.forename: Christian
authors.initials: C
authors.lastname: Munck
authors.forename: Jens
authors.initials: J
authors.lastname: Helby
authors.forename: Celeste
authors.initials: C
authors.lastname: Porsbjerg
authors.forename: Lars H
authors.initials: LH
authors.lastname: Hansen
authors.forename: Vibeke
authors.initials: V
authors.lastname: Backer
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001249:Asthma / Q000150:complications* / Q000453:epidemiology; D001944:Breath Tests / Q000379:methods; D001985:Bronchial Provocation Tests; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007249:Inflammation / Q000503:physiopathology*; D018836:Inflammation Mediators / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D015999:Multivariate Analysis; D009504:Neutrophils / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D011237:Predictive Value of Tests; D018570:Risk Assessment; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D013183:Sputum / Q000166:cytology; D018709:Statistics, Nonparametric; D055815:Young Adult
chemical_list: D018836:Inflammation Mediators; D009569:Nitric Oxide