Heterogeneity of lower airway inflammation in children with severe-persistent asthma.

RATIONALE

The treatment of children with severe-persistent asthma remains problematic. Recent studies suggest that stratification of this cohort by inflammatory type may be useful in designing effective treatment strategies. In this study, we examined the inflammatory profile in bronchoalveolar lavage fluid from children with severe-persistent asthma and compared this profile with serum IgE levels.

METHODS

The inflammatory profile in the bronchoalveolar fluid from 32 children who met criteria for severe-persistent asthma as defined by the Severe Asthma Research Program (SARP) were analyzed retrospectively. Inflammatory patterns were classified as neutrophilic, eosinophilic, mixed, or pauci-granulocytic. Serum total IgE was measured prior to bronchoscopy and determined by ELISA at each hospital's lab by standard procedures.

RESULTS

The most common pattern of inflammation in this cohort was neutrophilic (37.5%) followed by eosinophilic (28.1%), mixed (21.9%), and pauci-granulocytic (11.1%). The odds ratio of an eosinophilic BAL pattern for patients with an elevated serum IgE was 4.67 (CI 0.78-28, P = 0.12). A correlation between serum IgE levels and BAL eosinophil percentages was present (P = 0.04).

CONCLUSIONS

To our knowledge, ours is one of few studies to systematically investigate the pattern of lower airway inflammation in children with severe-persistent asthma. Our results differ from a recent investigation in children, showing more heterogeneity and a greater proportion of neutrophilic inflammation. Further investigation is required to determine whether specific inflammatory patterns are associated with specific etiologies, and whether individualized therapy is warranted.