Blood eosinophil count correlates with alveolar damage in emphysema-predominant COPD

Area of Science:

• Pulmonology
• Immunology
• Radiology

Background:

• Blood eosinophil count is a known biomarker in chronic obstructive pulmonary disease (COPD) management.
• The precise role of eosinophils in COPD pathogenesis remains incompletely understood.
• This study investigates the link between blood eosinophil levels and structural lung changes in COPD.

Purpose of the Study:

• To explore the relationship between blood eosinophil count and clinical parameters in COPD patients without asthma.
• To assess correlations between blood eosinophil count and specific lung structural changes identified via chest CT.
• To evaluate eosinophil infiltration in lung tissue concerning low attenuation areas (LAA) in COPD.

Main Methods:

• Ninety-three COPD patients without asthma were prospectively studied.
• Blood eosinophil count, serum IgE, serum periostin, and chest CT scans were analyzed.
• Eosinophilic COPD defined as blood eosinophil count ≥300/µL; correlations with airway wall thickness and LAA were examined.

Main Results:

• 19.3% of COPD patients met the criteria for eosinophilic COPD (mean count 212.1/µL).
• Blood eosinophil count correlated with white blood cells, basophils, CRP, and sputum eosinophils.
• In the thin airway wall group, eosinophil count positively correlated with LAA percentage and negatively with diffusing capacity.

Conclusions:

• A subset of COPD patients without asthma exhibits elevated blood eosinophil counts.
• Alveolar damage and central airway wall thickening in COPD may be associated with eosinophilic inflammation.
• These findings highlight a potential phenotype of eosinophilic COPD without concurrent asthma.