Systemic IL-26 correlates with improved asthma control in allergic children with asthma
Given that IL-26 is elevated systemically in dog allergen-sensitized children with asthma, we considered whether IL-26 may be a marker of disease severity in asthma. To assess this, we compared the systemic concentration of IL-26 with subjective symptom assessment questionnaires and objective spirometry values. Interestingly, we observed that systemic IL-26 values correlate with increasing, rather than decreasing, ACT scores (Fig. 4 ). However, we did not find any statistically significant correlations between IL-26 and either AQLQ scores or spirometry values, including FEV1 (data not shown).
Despite a lack of correlation between systemic IL-26 and FEV1, we were interested in whether IL-26 levels might also correlate with other objective markers of asthma severity in a similar manner to the subjective correlation to ACT scores. To assess this, we converted each subject’s daily inhaled corticosteroid dose to the equivalent dose of beclomethasone and compared this with their respective systemic IL-26 concentration. We discovered that increasing systemic IL-26 values correlate with decreasing inhaled daily corticosteroid dose (Fig. 5A ).