Immune dysregulation in children with allergic asthma, a close relationship between IL-17 but not IL-4 or IFN-, and disease severity

Background : Allergic asthma is a chronic inflammatory disease of airway that often determined with degrees of inflammation, hypersensitivity, bronchial constriction and airway changes. Th1, Th2 and Th17 cells are the main cells involved in the pathophysiology of asthma. . Therefore, this study evaluated Th1, Th2, and Th17 cells functions by assessment the expression of INF-g, IL-4, and IL-17 genes and protein levels in asthmatic patients and healthy controls, In order to have a close look at immune dysregulation in allergic asthma. Materials and methods: A total of 34 Iranian ethnicity people including 24 patients with allergic asthma and 10 healthy controls were enrolled. All participants peripheral blood mononuclear cells (PBMCs) were isolated and cDNA was synthesized following RNA extraction. Gene’s expressions and protein levels of INF-g, IL4 and IL17 were evaluated by Real-time Polymerase chain reaction and sandwich ELISA, respectively, Results: The results of this study showed that the expression of IL-4 and IL-17 genes of patients significantly increased in comparison with the control group (p=0.048, p=0.021, respectively) but the expression of IFN-g gene significantly decreased in the group of patients (p=0.021). Furthermore, Analysis of the expression of IL-4 and IFN -g genes revealed that the IL4/ IFN-g ratio in the group of patient  is significantly higher than the control group. (P = 0.039)   Conclusion: High expressions of IL-17 and IL-4 mRNA and prominent serum levels of these cytokines in asthmatic patients compared to healthy controls, may highlight the role of Th2 and Th17 cells in pathogenesis of asthma. An increased IL-17 expression/production in severe form of asthma, may lead therapeutic strategies on Th17 cells.