IL13 and allergic asthma: The main clinical features of allergic asthma result from the action of different cytokines secreted from activated CD4+ T-helper 2 (Th2) cells, which leads to IgE production (IL-4) and mast cell activation, mucus secretion (IL-13), bronchial hyper-responsiveness (IL-13) and eosinophilic lung inflammation (IL-5) [4,5].