Eosinophilic COPD―A Distinct Phenotype of the Disease

Chronic Obstructive Pulmonary Disease (COPD) has been traditionally associated with neutrophilic inflammation of the bronchi. Studies from the early 1990s demonstrated that eosinophils may also migrate into the lower airways of patients with COPD and their increased numbers can be noticed during exacerbations as well as stable disease. Eosinophilic phenotype of COPD is characterized by several unique features, i.e., a specific pattern of airway inflammation and distinct clinical course or susceptibility to corticosteroid treatment. In this paper, we present an up-to-date review of the literature on clinical characteristics of eosinophilic COPD, as well as the role of eosinophils as a biomarker-guided therapy in COPD.