The Role of Blood Eosinophils in the Management of COPD: An Attempt to Answer the Important Clinical Questions.

Blood eosinophils have been proposed as a surrogate biomarker of airway eosinophilia that can be used for treatment decisions in patients with COPD, mainly for the identification of candidates for the initiation or withdrawal of therapy with inhaled corticosteroids, as well as for the identification of patients at future risk of exacerbations. In this manuscript we review the recent literature on blood eosinophils in the management of patients with COPD, in an attempt to answer the major questions that are relevant for the practicing clinician. A growing body of evidence suggests that eosinophilic COPD may constitute a separate phenotype of the disease with distinct clinical features and blood eosinophils may represent a potential candidate surrogate marker for specific COPD patients. Several points still need to be clarified, including the role of eosinophils for the identification of candidates for future COPD therapies, yet blood eosinophils plausibly represent the most dependable and promising biomarker for the precision management of COPD today.