Methods: To compare airway inflammation in young (20 to 40 years of age) vs older patients with asthma, induced sputum from younger (n=39) and older (n=36) inner-city asthmatics was collected and accessed for cell count differentials, Treg cells and cytokine protein expression. To control for the effect of aging itself, which, by itself, may be associated with increased systemic inflammation, sputum was collected from younger (n=23) and older (n=19) non-asthma subjects as well. Asthma history and health-care utilization, current medications, degree of airflow obstruction and reversibility, asthma control (ACT), asthma-related quality of life (mini-AQLQ), atopy, and co-morbidities were obtained.
Results: Older asthmatics had significantly elevated sputum neutrophils (28.6±5% vs. 11±5.2%, p<0.001), eosinophils (8.34±1.9% vs.3.43±2.01%, p=0.02), IL-6, TNF-α, GM-CSF, IL-1β, IL-27, and increased Treg cells (CD3+CD4+Foxp3+CD127low) (12.4% vs 9.89, p=0.2) compared to younger patients with asthma.
Conclusions: These findings indicate that the pattern of airway inflammation in asthma is different in older patients, and is a pattern typically associated with a decreased responsive to inhaled corticosteroids. This data may possibly explain a greater risk for morbidity and mortality in older patients with asthma and further point to the need to identify treatments directed towards the characteristics of inflammation seen in this age group.