Indeed gene variants in TSLP and IL33 are associated with increased expression of these epithelial alarmins (Gudbjartsson et al., 2009; He et al., 2009; Ferreira et al., 2011; Harada et al., 2011; Li et al., 2015; Shrine et al., 2019), and ex vivo studies have demonstrated higher expression levels of TSLP and IL-33 in airway epithelial cells derived from asthma patients cultured at air-liquid-interface (ALI) compared to healthy controls (Hackett et al., 2013). This evidence concerns the gene IL33 and asthma.