IL-25 expression in induced sputum may serve as a reliable biomarker in children with bronchial asthma

Asthma is a chronic respiratory disease characterized by reversible airway obstruction and persistent airway inflammation, presenting as a highly heterogeneous disorder in children. Further understanding of its complexity is essential to identify applicable biomarkers and targeted therapies. Interleukin-25 (IL-25) has been shown to play a critical role in the pathogenesis of asthma.

To investigate the association between IL and 25 expression and clinical characteristics, we enrolled46 children with asthma (age 6-17 years)and15 age-matched healthy controls. Asthma patients were stratified intoGroup A (untreated, n = 24)andGroup B (treatment-controlled, n = 22). IL-25 protein levels in serum and IL-25 mRNA in induced sputum were quantified usingELISA and PCR, respectively.

No significant intergroup differences existed in age (P = 0.32), sex (P = 0.67), or BMI (P = 0.144).IL-25 mRNA in sputumwas significantly elevated in both groups versus controls (P < 0.001 in Group A and P < 0.05 in Group B).Sputum IL-25 protein levelswerehigher in Group A versus controls (P < 0.001) and Group B (P < 0.05). IL-25 mRNA expression in sputumwas significantly higher in Group A (without anti-asthma drugs) compared to Group B (with controlled asthma treated with anti-asthma drugs) (P < 0.05 in both induced sputum and blood). Furthermore, IL-25 mRNA expression correlated with CRP (P = 0.007), FeNO (P = 0.04), FEV₁/FVC (%) (P = 0.01), induced sputum eosinophil count (%) (P = 0.03), disease severity (P = 0.042), and anti-asthma treatment (P < 0.05). Notably, IL-25 levels in induced sputum decreased significantly at both molecular and gene levels following anti-asthma treatment, suggesting its potential as a biomarker for evaluating treatment efficacy and asthma control.

IL-25 expression in induced sputum may serve as a reliable biomarker in children with bronchial asthma, though further large-scale studies are needed to confirm these findings.