TSLP and asthma: There is now strong evidence within the literature that impairment of epithelial barrier function in asthma is a key player in the disease pathogenesis through the initiation of airway inflammation and remodeling via the release of alarmins (e.g., TSLP, IL-25 and IL-33 expression) (Borish and Steinke, 2011; West et al., 2012; Paplińska-Goryca et al., 2018; Chan et al., 2019).