Soluble receptor for advanced glycation end products and soluble interleukin-4 receptor in plasma and exhaled breath condensate as potential markers of asthma severity in children

Introduction. Asthma in children is characterized by chronic inflammation of the lower airways. The verification of reliable pro-inflammatory biomarkers, particularly non-invasive ones, is crucial for the diagnosis and treat[1]ment of childhood asthma. Aim. To evaluate the levels of soluble receptors for advanced glycation end products (sRAGE) and soluble interleukin-4 receptor (sIL-4R) in blood plasma and exhaled breath condensate (EBC) as potential biomarkers of bronchial asthma severity in children. Materials and methods. The study enrolled 195 children aged 6-17 years: 104 children with asthma and 91 children without any history of atopic diseases at baseline or during examination. The diagnosis and severity assessment of asthma were determined according to the Global Initiative for Asthma guidelines (GINA, 2021). EBC samples were collected using RTube devices (Respiratory Research, USA). The levels of sRAGE and sIL-4R were measured using magnetic bead-based multiplex immunoassay (MAGPIX, Luminex, USA). Results. Among 169 analyzed EBC samples, sRAGE was not detected in any sample above the minimum detectable level (14 pg/mL). In contrast, sIL- 4R levels exceeding the minimum detectable level (3 pg/mL) were found in 166 samples (98%). Plasma sRAGE levels were significantly lower in children with asthma (197.7 pg/mL) compared to controls (229.0 pg/mL; p=0.017). Similarly, EBC sIL-4R concentrations were significantly lower in children with asthma (120.3 pg/mL) compared to the control group (165.4 pg/mL; p<0.001). A statistically significant correlation was observed between plasma sRAGE levels and asthma severity (p=0.013, Kruskal-Wallis test). Conclusion. The measurement of plasma sRAGE and EBC sIL-4R levels appears to be a promising approach in developing novel biomarkers for the diagnosis, severity assessment, and monitoring of bronchial asthma in children.