Association between pathogens detected using quantitative polymerase chain reaction with airway inflammation in COPD at stable state and exacerbations..pdf (1.01 MB)
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Association between pathogens detected using quantitative polymerase chain reaction with airway inflammation in COPD at stable state and exacerbations

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journal contribution
posted on 16.02.2016, 15:57 by Bethan L. Barker, Koirobi Haldar, H. Patel, I. D. Pavord, Michael R. Barer, Christopher Edward Brightling, M. Bafadhel
BACKGROUND: Relationships between airway inflammation and respiratory potentially pathogenic microorganisms (PPMs) quantified using quantitative polymerase chain reaction (qPCR) in subjects with COPD are unclear. Our aim was to evaluate mediators of airway inflammation and their association with PPMs in subjects with COPD at stable state and during exacerbations. METHODS: Sputum from 120 stable subjects with COPD was analyzed for bacteriology (colony-forming units; total 16S; and qPCR targeting Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae), differential cell counts, and inflammatory mediators using the Meso-Scale Discovery Platform. Subjects were classified as colonized if any PPM was identified above the threshold of detection by qPCR. Symptoms were quantified using the visual analog scale. RESULTS: At stable state, 60% of subjects were qPCR positive for H influenzae, 48% for M catarrhalis, and 28% for S pneumoniae. Elevated sputum concentrations of IL-1β, IL-10, and tumor necrosis factor (TNF)-α were detected in samples qPCR positive for either H influenzae or M catarrhalis. Bacterial loads of H influenzae positively correlated with IL-1β, IL-8, IL-10, TNF-α, and symptoms; and M catarrhalis correlated with IL-10 and TNF-α. H influenzae qPCR bacterial load was an independent predictor of sputum TNF-α and IL-1β. In 55 subjects with paired exacerbation data, qPCR bacterial load fold change at exacerbation in M catarrhalis but not H influenzae correlated to changes in sputum TNF-α and IL-1β concentrations. CONCLUSIONS: At stable state, H influenzae is associated with increased airway inflammation in COPD. The relationship between bacterial load changes of specific pathogens and airway inflammation at exacerbation and recovery warrants further investigation.

History

Citation

Chest, 2015, 147 (1), pp. 46-55

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/School of Medicine/Department of Infection, Immunity and Inflammation

Version

VoR (Version of Record)

Published in

Chest

Publisher

American College of Chest Physicians (ACCP), Elsevier

issn

0012-3692

eissn

1931-3543

Copyright date

2015

Available date

16/02/2016

Publisher version

http://www.sciencedirect.com/science/article/pii/S0012369215302348

Language

en