Since the roles of IL-4/-13 are pleiotropic with effects on eosinophil transmigrations across endothelium, mucus secretion, B-cell immunoglobulin E production, and enhanced contractility of airway smooth muscle cells, biologic treatment targeting IL-4/-13 may effectively improve asthma in a broader population, not necessarily solely in patients with significant airway eosinophilia (Greenfeder et al., 2001; Castro et al., 2020; Ricciardolo et al., 2021c). The gene discussed is IL4; the disease is asthma.