The pathophysiologies of allergic diseases are dominated by IgE-mediated inflammation and the type 2 immune response (2), and type 2 helper T cells (Th2 cells) and type 2 innate lymphoid cells (ILC2s) play roles in the development of the type 2 immune response by releasing cytokines such as IL-4, IL-5, IL-9, and IL-13 (3). This evidence concerns the gene IL9 and allergic disease.