Emphysematous Phenotype is Characterized by Low Blood Eosinophils: A Cross-Sectional Study

ABSTRACTSputum and blood eosinophils are proposed as candidate biomarkers for the identification of chronic obstructive pulmonary disease (COPD) patients at risk for exacerbation and treatment response. In this study, we evaluated the associations of eosinophils with the presence of emphysema in COPD patients. Induced sputum and blood eosinophil measurements were performed in consecutive COPD patients. Patients underwent lung function testing and high resolution computed tomography (HRCT) of the chest and the presence of emphysema was quantified. Patients with emphysematous lesions in ≥15% of the pulmonary parenchyma were considered having significant emphysema. Ninety-eight patients were included in the study. Patients with significant emphysema had lower blood eosinophil counts compared to patients without emphysema [median (IQR) 34.6 (0.0, 63.0) vs. 169.0 (110.0, 260.0) cells/µL, p < 0.001]; similar results were observed for the percentage (%) of blood eosinophils, but no difference was observed for sp...