In T2-high asthma, CD4+T helper 2 (Th2) cells and innate lymphoid cells group 2 (ILC2), eosinophils, immunoglobulin E (IgE) and T2 cytokines such as interleukin (IL)-4, IL-5 and IL-13 contribute to its pathogenesis. The gene discussed is IL4; the disease is asthma.