Highly sensitive multiplex assay of interleukins in exhaled breath condensate from children with bronchial asthma: diagnostic significance of IL-13 and IL-17A

Interleukins play a key role in development of bronchial asthma endotypes, thus determining individual clinical course of the disease and the efficiency of therapy. Exhaled breath condensate (EBC) represents a promising non-invasive biomaterial for assessing local airway inflammation in asthma. Only limited data exist on the opportunity of cytokines detection in EBC of pediatric patients. The aim of our study was to assess the opportunity of detection and diagnostic significance of IL-4, IL-5, IL-13, and IL-17A in EBC of children with asthma using high-sensitivity multiplex analysis. The study included 169 children aged 6-17 years (104 with asthma and 65 healthy controls). EBC was collected using RTube (Respiratory Research, USA), samples were concentrated, and interleukin levels were determined by multiplex analysis on the MAGPIX (Luminex, USA) platform. Analysis of interleukins in exhaled air condensate showed that children with bronchial asthma exhibit statistically significant changes compared to the control group. Children with asthma showed significantly increased detection rates of IL-13 (53.9% vs 30.8%, p = 0.003) and IL-17A (57.7% vs 27.7%, p = 0.001) compared to controls. The detection frequency of these cytokines progressively increased with disease severity, reaching 72.7% for IL-13 and 63.6% for IL-17A in severe asthma. Our results demonstrate the possibility of detecting key cytokines in exhaled air condensate in children with bronchial asthma using highly sensitive multiplex analysis after prior concentration of samples. Detection of IL-13 and IL-17A in EBC can be considered a potential non-invasive biomarker of asthma severity in children. However, further studies with larger patient populations and standard sample concentration technique are required for clinical implementation of the method. These data demonstrate a promise for usage of EBC for non-invasive assessment of local airway inflammation in children with bronchial asthma.