Inflammatory signatures in asthma–COPD overlap:cytokine profiling across asthma subtypes

Abstract English: Objective This study aimed to compare clinical characteristics and plasma cytokine profiles among patients with asthma, asthma combined with smoking history, asthma with fixed airflow obstruction (FAO) and asthma–COPD overlap (ACO), to identify distinct inflammatory signatures. Methods A prospective, cross-sectional study was conducted involving 120 clinically stable asthma patients stratified into four groups: asthma (n = 56), asthma + smoking (n = 15), asthma + FAO (n = 34) and ACO (n = 15). Clinical assessments, spirometry and multiplex cytokine analysis were performed to evaluate inflammatory and functional parameters. Results Significant elevations in IL-1β, IL-17 and tumour necrosis factor alpha (TNF-α) were observed in the ACO group compared to asthma and asthma + FAO cohorts (P < 0.01). Specifically, IL-1β levels in ACO reached 3.8 ng/L [2.7–4.8], nearly threefold higher than in asthma (1.4 ng/L) and asthma + FAO (1.0 ng/L). IL-17 and TNF-α concentrations were similarly elevated in ACO (16.4 ng/L and 18.8 ng/L, respectively). No significant differences were found in IFN-α, IFN-γ, IL-4, IL-12 or IL-13. Conclusion ACO exhibits distinct immunopathological characteristics, notably elevated concentrations of IL-1β, IL-17 and TNF-α relative to asthma and asthma + FAO cohorts. The combined use of spirometric indices and biomarker profiling may enhance phenotypic stratification and inform the development of targeted biologic therapies for obstructive airway diseases.