In this study we examined the effects of TSLP at both sides (apical/basal) of the human epithelial barrier using a multi-scale approach that included an in vitro model of polarized, primary differentiated HBEC at air-liquid interface (ALI), human airway smooth muscle cells (HASMC) and clinical experiments in nasal airway secretions obtained during naturally occurring rhinovirus-induced asthma exacerbations. This evidence concerns the gene TSLP and asthma.