CXCL8 and chronic rhinosinusitis without nasal polyps: In the pilot experiments, we found a concentration-dependent effect of clarithromycin and dexamethasone on the reduction of IL-8, and induction of IL-10 and Clara cell 10-kD protein (CC10) production in sinonasal mucosa from CRSsNP, and eosinophilic and non-eosinophilic CRSwNP with a maximal response at a concentration of 10−5 mol/L (P < 0.05) (Fig. 1).