IL4 and asthma: Type 2 innate lymphoid cells (ILC2), type 2 T-helper (Th2) cells, and related cytokines (such as IL-4, IL-5, and IL-13) are major players in the pathological changes and clinical symptoms of asthma, and increasing attention has been paid to anti-IL-5, anti-IL-5Rα, and anti-IL-4Rα therapy [8].