High Blood Eosinophil Count at Stable State is Not Associated with Airway Microbiota Distinct Profile in COPD

Abstract

Purpose

The heterogeneity of clinical features in COPD at stable state has been associated with airway microbiota. Blood eosinophil count (BEC) represents a biomarker for a pejorative evolution of COPD, including exacerbations and accelerated FEV₁ decline. We aimed to analyse the associations between BEC and airway microbiota in COPD at stable state.

Patients and Methods

Adult COPD patients at stable state (RINNOPARI cohort) were included and characterised for clinical, functional, biological and morphological features. BEC at inclusion defined 2 groups of patients with low BEC <300/mm³ and high BEC ≥300/mm³. Sputa were collected and an extended microbiological culture was performed for the identification of viable airway microbiota.

Results

Fifty-nine subjects were included. When compared with the low BEC (n=40, 67.8%), the high BEC group (n=19, 32.2%) had more frequent exacerbations (p<0.001) and more pronounced cough and sputum (p<0.05). The global composition, the number of bacteria per sample and the α-diversity of the microbiota did not differ between groups, as well as the predominant phyla (Firmicutes), or the gender repartition.

Conclusion

In our study, high BEC in COPD at stable state was associated with a clinical phenotype including frequent exacerbation, but no distinct profile of viable airway microbiota compared with low BEC.

Keywords:

• COPD
• eosinophil
• sputum
• microbiota

Data Sharing Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Ethics Approval and Informed Consent

The study was approved by the regional ethics committee (Comité de Protection des Personnes—Dijon EST I, no. 2016-A00242-49). Informed consent was obtained from all the patients. Our Study complies with the Declaration of Helsinki.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

J.M. Perotin reports lecture honoraria from AstraZeneca, and support for attending meetings from AstraZeneca and Chiesi; outside the submitted work. C. Launois reports support for attending meeting from Chiesi; outside the submitted work. V. Dormoy reports lecture honoraria from Chiesi and AstraZeneca; outside the submitted work. G. Deslée reports lecture honoraria from Chiesi, AstraZeneca, Boehringer Ingelheim, Sanofi and GlaxoSmithKline; outside the submitted work. The authors report no other conflicts of interest in this work.

Additional information

Funding

There is no funding to report.