Abstract
BACKGROUND: Higher blood eosinophil counts are associated with greater lung function decline in patients with COPD, and a relationship between higher sputum eosinophil counts and greater emphysema has been reported. The aim of the current study was to investigate a role for eosinophils in alveolar septal damage, which may contribute to emphysema and lung function decline in COPD patients. METHODS: We quantified Luna positive alveolar septal eosinophil counts (ASEC) in peripheral lung tissue blocks from 48 COPD patients versus 27 smokers and 15 nonsmokers and examined the relationship between eosinophil numbers and alveolar tissue damage using histology techniques. RESULTS: The numbers of ASEC were greater in COPD compared to controls (p≤0.02), and there was a significant correlation between ASEC and alveolar septal damage in a subgroup of COPD patients (rho=0.4, p=0.03). CONCLUSION: This association suggests a role for eosinophils in the pathogenesis of emphysema in a subset of COPD.