IL17A and asthma: Overall, these cells' and mediators' interactions and functions in asthma patients result in the extraordinary lung structures and dyspnea that compose the basic characteristics of asthma [13].In particular, the IL-17A, a secretion cytokine of TH17 cells, increases contractility of airway smooth muscle which contributes to allergen-induced airway hyperresponsiveness in asthma [14].