IL4 and asthma: Recent studies have extended this understanding and suggested that apart from TH2 cells, other innate immune cells, including mast cells, basophils, group 2 ILCs, IL-4- and/or IL-13-activated macrophages (“M2”), and a small portion of IL-4-secreting natural killer (NK)/NKT cells, also contribute to TH2 cell induced cytokine production in asthma; as a result, the terminology has gradually shifted from “TH2 cell-high” to “type 2-high” asthma (11).