Monitoring sputum eosinophils in mucosal inflammation and remodelling: a pilot study

Area of Science:

• Pulmonology
• Immunology
• Pathology

Background:

• Sputum eosinophil normalization reduces asthma exacerbations.
• The impact of sputum-guided treatment on airway remodeling is not well understood.

Purpose of the Study:

• To compare bronchial inflammation and collagen deposition in mild asthmatics over two years using sputum eosinophil counts (SS) versus clinical criteria (CS) for treatment guidance.
• To determine if normalizing sputum eosinophils affects airway remodeling markers.

Main Methods:

• Pilot study with 20 mild asthmatic patients randomized to SS or CS.
• Bronchial biopsies taken at baseline and after two years of treatment.
• Immunostaining for inflammatory cells, MUC5A, and collagen.

Main Results:

• Both SS and CS groups showed similar inhaled corticosteroid doses and improved FEV1.
• SS reduced mucosal lymphocytes and eosinophils; CS reduced activated eosinophils and neutrophils.
• MUC5A staining decreased in the SS group but not in the CS group.
• No significant changes in subepithelial collagen deposition were observed in either group.

Conclusions:

• Sputum eosinophil normalization in asthma treatment reduces mucosal inflammation and MUC5A expression.
• This strategy does not impact subepithelial collagen deposition in mild to moderate asthma.
• Sputum eosinophil counts can guide asthma treatment to reduce inflammation without affecting airway remodeling markers.