title: Inflammation in sputum relates to progression of disease in subjects with COPD: a prospective descriptive study.
abstract: BACKGROUND
  Inflammation is considered to be of primary pathogenic importance in COPD but the evidence on which current understanding is based does not distinguish between cause and effect, and no single mechanism can account for the complex pathology. We performed a prospective longitudinal study of subjects with COPD that related markers of sputum inflammation at baseline to subsequent disease progression.
  
  
  METHODS
  A cohort of 56 patients with chronic bronchitis was characterized in the stable state at baseline and after an interval of four years, using physiological measures and CT densitometry. Sputum markers of airway inflammation were quantified at baseline from spontaneously produced sputum in a sub-group (n = 38), and inflammation severity was related to subsequent disease progression.
  
  
  RESULTS
  Physiological and CT measures indicated disease progression in the whole group. In the sub-group, sputum myeloperoxidase correlated with decline in FEV1 (rs = -0.344, p = 0.019, n = 37). LTB4 and albumin leakage correlated with TLCO decline (rs = -0.310, p = 0.033, rs = -0.401, p = 0.008, respectively, n = 35) and IL-8 correlated with progression of lung densitometric indices (rs = -0.464, p = 0.005, n = 38).
  
  
  CONCLUSIONS
  The data support a principal causative role for neutrophilic inflammation in the pathogenesis of COPD and suggest that the measurement of sputum inflammatory markers may have a predictive role in clinical practice.
authors.affiliation: Department of Respiratory Medicine, University Hospitals of Coventry and Warwickshire, Clifford Bridge Road, Coventry, CV2 2DX, UK. david.parr@uhcw.nhs.uk
authors.forename: David G
authors.initials: DG
authors.lastname: Parr
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: White
authors.forename: Darren L
authors.initials: DL
authors.lastname: Bayley
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Guest
authors.forename: Robert A
authors.initials: RA
authors.lastname: Stockley
mesh_terms: D000368:Aged; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D007249:Inflammation / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000473:pathology* / Q000503:physiopathology; D012129:Respiratory Function Tests; D012307:Risk Factors; D013183:Sputum / Q000737:chemistry / Q000502:physiology*