Abstract
Background: Interleukin (IL)-26 is produced by T helper type 17
(Type 17) cells and exerts immunomodulatory plus antimicrobial effects.
Previous studies show that local IL-26 concentrations in the airways are
higher in patients with uncontrolled than in those with controlled
asthma, and that this intriguing cytokine bears biomarker potential.
Here, we determined how systemic IL-26 relates to allergen
sensitization, asthma severity, and to IL-17A in children.
Methods: Serum samples were obtained from children with (n=60)
and without (n=17) sensitization to dog allergen, and IL-26 and IL-17A
protein concentrations were measured using ELISA. Self-reported history,
including medication use and validated symptom-based questionnaire
scores, was recorded.
Results: The serum concentrations of IL-26 were enhanced in
allergen-sensitized subjects and correlated with those of IL-17A in a
positive manner. However, the IL-26 concentrations did not markedly
differ between allergen-sensitized subjects with and without asthma,
eczema, allergic rhinitis, or a history of food allergy. Notably, IL-26
concentrations correlated with increasing Asthma Control Test (ACT)
scores in a positive manner and with inhaled corticosteroid in a
negative manner, amongst sensitized subjects with asthma. Moreover,
subjects with asthma requiring ≥1 course of oral corticosteroids in the
preceding 12 months had decreased IL-26 concentrations.
Conclusion: This study forwards evidence that systemic IL-26,
just like IL-17A, is involved in allergen sensitization among children.
The association of systemic IL-26 with improved asthma control is
compatible with the cellular sources being recruited into the airways in
severe asthma, which supports that this kinocidin bears potential as a
biomarker and therapeutic target.