Association of selected inflammatory biomarkers with cough reflex sensitivity in asthmatic children

Bronchial asthma is the most common chronic respiratory disease of childhood. Cough is one of its defining symptoms. This study investigated the associations between selected inflammatory biomarkers and cough reflex sensitivity after capsaicin inhalation in children with mild and moderate well-controlled type 2 endotype asthma compared with non-asthmatic probands. Sensitivity to the cough reflex was measured by recording the cough response after capsaicin inhalation. The sandwich ELISA method was used to measure serum concentrations of the investigated potential inflammatory biomarkers (interleukin 13, interleukin 1beta, eosinophil-derived neurotoxin). The acquired data were statistically evaluated according to descriptive analyses for summarization and comparison between cough reflex sensitivity parameters and individual biomarker values in the observed and control groups modeled by a simple linear regression model. Statistical significance was defined as p<0.05. We showed a statistically significant association (p-value 0.03) between cough reflex sensitivity - C2 value (capsaicin concentration required for two cough responses) and interleukin 1beta serum concentrations in the asthma group compared with the control group of non-asthmatic children. Our results support the possibility of interleukin 1beta as a potential additive inflammatory biomarker used in clinical practice in children with asthma because of its correlation with the activity of the afferent nerve endings in the airways.