IL4 and asthma: The levels of Th2 cell-related factors are significantly increased in patients with asthma [22], and Th2 cell-related cytokines, such as IL-4, IL-5, and IL-13, have many functions related to asthma occurrence, such as stimulating the secretion of IgE by activating B cells, inducing eosinophilia and airway hyper-responsiveness, and stimulating goblet cell metaplasia [25,26,27].