Bronchial CD8 cell infiltrate and lung function decline in asthma.

Area of Science:

• Pulmonary Medicine
• Immunology
• Respiratory Research

Background:

• Asthma patients experience accelerated lung function decline, potentially leading to irreversible airway obstruction.
• This decline is often attributed to specific airway inflammation and remodeling processes.

Purpose of the Study:

• To assess the prognostic value of bronchial eosinophil and CD8+ T cell counts, and subepithelial reticular layer thickness.
• To correlate these factors with lung function decline over 7.5 years in asthma patients.

Main Methods:

• Prospective study of 32 asthma patients measuring lung function (FEV1) over 7.5 years.
• Analysis of bronchial biopsies at baseline and Year 2 for inflammation and remodeling markers.
• Correlation of biopsy findings with annual lung function decline (pre- and post-bronchodilator FEV1).

Main Results:

• Annual decline in post-bronchodilator FEV1 was greater than pre-bronchodilator FEV1, suggesting loss of reversibility.
• No significant correlation found between lung function decline and reticular layer thickness or eosinophil counts.
• A significant inverse correlation was observed between CD8+ T cell counts and annual decline in post-bronchodilator FEV1, confirmed at Year 2.

Conclusions:

• Bronchial CD8+ T cell infiltration is a significant predictor of asthma outcome, specifically FEV1 decline.
• The inflammatory phenotype in asthma holds prognostic relevance.
• Findings suggest the need for phenotype-specific therapeutic strategies in asthma management.