When basal cells of polyp- and non-polyp regions are cultured ex vivo, the enhanced response to IL-4/IL-13 is retained14 suggesting that epigenetic reprogramming of epithelial stem cells contributes to the chronic type 2 airway inflammation in asthma and CRSwNP, which extends to various locations and cell types (Fig. 2). Here, IL13 is linked to chronic rhinosinusitis with nasal polyps.