Late Breaking Abstract - Systemic IL-26 correlates with improved asthma control in children with allergic sensitization

Abstract

Background: IL-26 is an IL-10 family cytokine with pro- and anti-inflammatory effects. In a pilot study, sputum IL-26 concentrations correlated with worsening asthma severity amongst subjects with non-allergic asthma. Objective: To determine whether systemic IL-26 concentrations are increased in children sensitized to dog allergen in vivo and whether it correlates with markers of asthma severity and with the Th17 cytokine, IL-17A. Methods: Serum was obtained from a cohort of dog allergen-sensitized children (n = 60), with non-sensitized children (n = 17) as control subjects. Self-reported clinical history, including medication use and validated symptom-based questionnaire scores, was recorded. IL-26 and IL-17A concentrations were measured by ELISA. Results: Serum IL-26 and IL-17A concentrations were elevated in allergen-sensitized subjects, and IL-26 correlated positively with IL-17A. IL-26 concentrations did not differ significantly between allergen-sensitized subjects with and without asthma or eczema. However, IL-26 correlated positively with increasing Asthma Control Test (ACT) scores and negatively with inhaled corticosteroid dose amongst subjects with asthma. Moreover, subjects with asthma requiring ≥1 course of oral corticosteroids in the preceding 12 months demonstrated a decline in systemic IL-26 concentrations. Conclusion: Systemic IL-26 and IL-17A concentrations are increased in allergen-sensitized individuals compared to those without allergic sensitization, and systemic IL-26 may reflect a non-specific atopic state. Amongst asthmatic children, IL-26 correlates with improved asthma control, suggesting that systemic IL-26 may be associated with a protective effect in asthma.