Chronic obstructive pulmonary disease (COPD) is typically considered a neutrophil-driven inflammatory disease [1], but some individuals, particularly those with frequent exacerbations, show eosinophil-associated airway inflammation [2]. Elevated blood eosinophil count (BEC) is linked to a positive response to inhaled corticosteroids (ICS) and is used to guide ICS therapy, with the Global Initiative for Obstructive Lung Disease (GOLD) recommendations suggesting BEC thresholds of 100 and 300 cells/μL to predict ICS benefit [3].
