IL5 and asthma: It is well established that asthmatic airway inflammation associated with Th1/Th2 immune dysregulation [4, 5], The cytokines IL-4, IL-5 and IL-13 produced by Th2 cells are known to play important roles in asthma pathogenesis, particularly in eosinophilic asthma, they are critical for the accumulation of eosinophil and induction of immunoglobulin class switching to IgE [6, 7], meanwhile, they participate in mucus hypersecretion and airway hyperresponsiveness in asthma [8, 9].