Airway immune mediator levels during asthma‐like symptoms in young children and their possible role in response to azithromycin

Background: Asthma‐like symptoms in young children are orchestrated by the local airway immune response, but current knowledge largely relies on in vitro airway models. Azithromycin has been shown to reduce the duration of episodes with asthma‐like symptoms but efficacy may depend on the individual child's immune response.
Objectives: To investigate in vivo upper airway immune mediator levels during episodes with asthma‐like symptoms in young children and their ability to predict the clinical response to azithromycin treatment.
Methods: 535 children aged 0-3 years from the Copenhagen Prospective studies of Asthma in Childhood-2010 mother-child cohort were examined for immune mediator levels in samples of nasal epithelial lining fluid during episodes with asthma-like symptoms as well as in the asymptomatic state. In a sub.study, children with recurrent asthma-like symptoms were randomized to either a 3-day course of oral azithromycin (10 mg/kg) (n=32) or placebo (n=38). In the current study, we compared the pre-treatment immune mediator levels with the clinical response to treatment with azithromycin in an exploratory posthoc analysis.
Results: The immune mediator concentrations during vs outside episodes were significantly upregulated for IFN-γ (ratio 1.73), TNF-α (ratio 1.45) and IL-10 and high levels of CCL22 predicted better treatment response to azithromycin (p-values < 0.05).
Conclusion: Upper airway immune mediator levels were altered during episodes of asthma-like symptoms, and levels of TNF-α, CCL22 and IL-10 may predict the response to azithromycin treatment.