Neutrophil extracellular traps are associated with disease severity and microbiota diversity in patients with chronic obstructive pulmonary disease

Alison J. Dicker, Megan L. Crichton, Eleanor G. Pumphrey, Andrew J. Cassidy, Guillermo Suarez-Cuartin, Oriol Sibila, Elizabeth Furrie, Christopher J. Fong, Wasyla Ibrahim, Gill Brady, Gisli G. Einarsson, J. Stuart Elborn, Stuart Schembri, Sara E. Marshall, Colin N. A. Palmer, James D. Chalmers (Lead / Corresponding author)

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194 Citations (Scopus)
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Background Neutrophil extracellular traps (NETs) have been observed in the airway in patients with chronic obstructive pulmonary disease (COPD), but their clinical and pathophysiologic implications have not been defined. Objective We sought to determine whether NETs are associated with disease severity in patients with COPD and how they are associated with microbiota composition and airway neutrophil function. Methods NET protein complexes (DNA-elastase and histone-elastase complexes), cell-free DNA, and neutrophil biomarkers were quantified in soluble sputum and serum from patients with COPD during periods of disease stability and during exacerbations and compared with clinical measures of disease severity and the sputum microbiome. Peripheral blood and airway neutrophil function were evaluated by means of flow cytometry ex vivo and experimentally after stimulation of NET formation. Results Sputum NET complexes were associated with the severity of COPD evaluated by using the composite Global Initiative for Obstructive Lung Disease scale (P <.0001). This relationship was due to modest correlations between NET complexes and FEV 1, symptoms evaluated by using the COPD assessment test, and higher levels of NET complexes in patients with frequent exacerbations (P =.002). Microbiota composition was heterogeneous, but there was a correlation between NET complexes and both microbiota diversity (P =.009) and dominance of Haemophilus species operational taxonomic units (P =.01). Ex vivo airway neutrophil phagocytosis of bacteria was reduced in patients with increased sputum NET complexes. Consistent results were observed regardless of the method of quantifying sputum NETs. Failure of phagocytosis could be induced experimentally by incubating healthy control neutrophils with soluble sputum from patients with COPD. Conclusion NET formation is increased in patients with severe COPD and associated with more frequent exacerbations and a loss of microbiota diversity.

Original languageEnglish
Pages (from-to)117-127
Number of pages11
JournalJournal of Allergy and Clinical Immunology
Issue number1
Early online date13 May 2017
Publication statusPublished - Jan 2018


  • Haemophilus species
  • Neutrophils
  • chronic obstructive pulmonary disease
  • exacerbations
  • phagocytosis

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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