Predictive value of IL-35 and IL-17 in diagnosis of childhood asthma

This study aimed to evaluate the correlation between serum levels of IL-17 and IL-35 and the presence and severity of childhood asthma. The study was performed on 60 diagnosed asthmatic children, who were further classified into four groups according to the Global Initiative for Asthma Guidelines for Asthma Severity and Control (GINA) 2016, plus 30 age- and sex-matched apparently healthy children. All participants were subjected to full medical history, clinical examination, pulmonary function tests and laboratory evaluation in the form of complete blood count (CBC), serum total IgE, IL-17 and IL-35 by ELISA. Our results revealed that eosinophils count, IgE and IL-17 were significantly higher in the asthmatic group than the control group (p < .001), while IL-35 levels were significantly lower in asthmatics than control (p < .001). A strong negative correlation was found between serum IL-17 and serum IL-35; a positive correlation was found between serum IL-17 and both of serum total IgE and eosinophils counts in atopic asthmatic patients, and serum IL-35 showed significant negative correlations with both. ROC analysis of the data showed that the cut-off value of IL-35 level was <189.5 pg/mL and for IL-17 level, it was >13.1 pg/mL; this value could predict childhood asthma with sensitivity of 81.7% and 83.3%, and specificity of 76.7% and 70%, respectively. A combination of both cytokines yielded an increase in sensitivity to 95%. In conclusion, in the current study, IL-17 is upregulated while IL-35 is downregulated in childhood asthma with a significant negative correlation between both. These results suggest that both may play an important role in the pathogenesis of childhood asthma.