IL33 and chronic rhinosinusitis without nasal polyps: Even though Ryu et al. [4] demonstrated the ST2 cell population was over-expressed in CRSwNP tissues compared with chronic rhinosinusitis without nasal polyp (CRSsNP), and ST2-positive ILCs were a source of IL-13 in response to IL-33, there are still controversies about the expression levels of IL-33 in nasal polyp tissues.