Periostin is an extracellular matrix protein with an upregulated expression in airway epithelial cells and fibroblasts after activation by IL-13 and alarmin IL-33 (Wechsler et al., 2021) in patients with some types of asthma and allergic inflammation, but also in pulmonary fibrosis (Murata et al., 2018; Nukui et al., 2019; Katoh et al., 2020; Matsumoto, 2020). The gene discussed is POSTN; the disease is asthma.