Asthma and associated type 2 inflammation are driven by both the innate (type 2 innate lymphoid cells) and adaptive [T helper type 2 (Th2) cells] immune systems, characterized by the release of cytokines such as interleukin (IL)-4, IL-5, and IL-13, key pathophysiologic characteristics of asthma (18, 19). This evidence concerns the gene IL4 and asthma.