TLR4 and chronic rhinosinusitis without nasal polyps: Clarithromycin could up-regulate the mRNA expression of TLR4 in sinonasal mucosa from all CRS groups; while dexamethasone might enhance the TLR4 expression in sinonasal mucosa from CRSsNP and non-eosinophilic CRSwNP (Fig. 9d).