IL4 and respiratory system disorder: Asthma is a respiratory disease initiated by crosstalk between the innate and adaptive immunity (1); however, T helper 2 (Th2) cells play a crucial role in driving airway inflammation and bronchial hyper-responsiveness, due to secretion of type-2 cytokines including interleukin-4 (IL-4), IL-5, and IL-13 (2, 3).