Airway inflammation and etiology of acute exacerbations of chronic bronchitis

Chest. 2000 Dec;118(6):1557-65. doi: 10.1378/chest.118.6.1557.


Study objectives: The etiologic role of bacterial pathogens isolated from sputum culture in 40 to 50% of acute exacerbations of chronic bronchitis (AECB) is controversial. If bacterial pathogens cause these AECB, they should be associated with greater neutrophilic airway inflammation than pathogen-negative exacerbations.

Design: This hypothesis was tested by comparing levels of interleukin (IL)-8, tumor necrosis factor (TNF)-alpha, and neutrophil elastase (NE) in 81 sputum samples obtained from 45 patients with AECB. Four groups were compared. In the first three groups, nontypable Haemophilus influenzae (n = 20), Haemophilus parainfluenzae (n = 27), and Moraxella catarrhalis (n = 14) were isolated as sole pathogens, respectively. In the fourth group, only normal flora was isolated (n = 20). Paired samples, obtained from individual patients at different times, that differed in their culture results were also compared.

Setting: An outpatient research clinic at a Veterans Affairs Medical Center.

Patients: These patients were participating in a prospective, longitudinal study of the dynamics of bacterial infection in chronic bronchitis, for which they were seen in the study clinic on a monthly basis as well as when they were experiencing symptoms suggestive of AECB.

Interventions: None.

Measurements and results: H influenzae exacerbations were associated with significantly higher sputum IL-8, TNF-alpha, and NE. M catarrhalis exacerbations demonstrated significantly higher sputum TNF-alpha and NE when compared to pathogen-negative exacerbations. H parainfluenzae-associated exacerbations had an inflammatory profile similar to pathogen-negative exacerbations. Sputum elastase level distinguished bacterial from nonbacterial AECB and correlated with clinical severity of the AECB.

Conclusions: Increased airway inflammation associated with isolation of H influenzae and M catarrhalis supports an etiologic role of these pathogens in AECB.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acute Disease
  • Aged
  • Aged, 80 and over
  • Bronchitis / microbiology
  • Bronchitis / pathology*
  • Bronchitis / physiopathology
  • Chronic Disease
  • Fibrinogen / analysis
  • Haemophilus / isolation & purification
  • Haemophilus influenzae / isolation & purification
  • Humans
  • Inflammation
  • Inflammation Mediators / analysis
  • Interleukin-8 / analysis
  • Leukocyte Elastase / analysis
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Moraxella catarrhalis / isolation & purification
  • Prospective Studies
  • Sputum / chemistry
  • Sputum / cytology
  • Sputum / microbiology*
  • Tumor Necrosis Factor-alpha / analysis


  • Inflammation Mediators
  • Interleukin-8
  • Tumor Necrosis Factor-alpha
  • Fibrinogen
  • Leukocyte Elastase