IL4 and allergic asthma: It is reported that IL‐13 and IL‐4, cytokines released from Th2, are major drivers of asthma and appear to play a prominent role in MUC5AC expression and mucus production.45, 46 Th2 cytokines induce goblet cell hyperplasia, resulting in mucus overproduction and airway inflammation in allergic asthma.