Chronic obstructive pulmonary disease's eosinophilic phenotype: Clinical characteristics, biomarkers and biotherapy.

COPD is a chronic, heterogeneous inflammatory disorder of the airways with persistent and poorly reversible airflow limitation, causing symptoms such as cough, shortness of breath, and sputum production. Despite optimal treatment, some patients remain symptomatic due to the disease's heterogeneity, manifesting in various phenotypes. One notable phenotype involves eosinophilic inflammation, with a variable prevalence.