Eosinophilic cytokines and small airway dysfunction in women with COPD: correlation with exposure to biomass smoke versus tobacco smoking.

Background: Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease characterised by progressive airflow obstruction. Tobacco smoking is the leading cause of COPD (COPD-TS); however, chronic exposure to biomass smoke (COPD-BS) is the second risk factor. COPD-TS and COPD-BS are now considered different phenotypes, with COPD-BS having small airway dysfunction (SAD).

Objectives: Our primary aim was to investigate the correlation between SAD and the serum levels of interleukins implicated in the maturation and recruitment of eosinophils in women with COPD-BS and COPD-TS.

Methods: This cross-sectional study included 25 women with COPD-BS and 25 women with COPD-TS, and the relationship with SAD was assessed by impulse oscillometry (IOS), alongside measurements of interleukins (IL-1ra, IL-2, IL-4, IL-8, IL-9, IL-13, and IL-17) and eotaxin using the multiplex test (Bio-Plex), in addition to eosinophils total blood.

Results: Blood eosinophil count, cytokines, and eotaxin were higher in COPD-BS relative to COPD-TS. IOS measurements were higher in COPD-BS than in COPD-TS. R5-R20 positively correlated with the concentrations of all measured cytokines noted if COPD groups were analysed separately (P < 0.01).

Conclusion: Eosinophil counts and cytokines in COPD-BS positively correlate with small airway resistance as measured by IOS in R5-R20.