Immune Dysregulation in Children with Allergic Asthma: A Close Relationship Between IL-17 but not IL-4 or IFN-𝛾, and Disease Severity

Allergic asthma is a chronic airway inflammatory disease often determined with degrees of inflammation, hypersensitivity, bronchial constriction, and airway changes. Th1, Th2, and Th17 cells are the main cells involved in asthma pathophysiology. To evaluate Th1, Th2, and Th17 functions by assessing INF-𝛾, IL-4, and IL-17 gene and protein levels in asthma patients and healthy controls. In total, 44 individuals of Iranian ethnicity including 24 patients with allergic asthma and 20 healthy controls were enrolled. Peripheral blood mononuclear cells of all participants were isolated and cDNA was synthesized following RNA extraction. Gene expression and protein levels of INF-𝛾, IL-4, and IL-17 were evaluated by real-time polymerase chain reaction and sandwich ELISA, respectively. The results of this study showed that the gene expression of IL-4 and IL-17 in patients was increased significantly compared to the control group (p = 0.046 and 0.03, respectively) whereas that of IFN-𝛾 was significantly decreased in the group of patients (p = 0.021). Compared to the healthy controls, serum levels of IL-17 and IL-4 were significantly increased in asthma patients (p = 0.015 and 0.03, respectively). Higher IL-17 and IL-4 mRNA expression and serum levels in asthma patients than healthy controls highlight the role of Th2 and Th17 cells in asthma pathogenesis and their potential as therapeutic targets.