Dexamethasone and clarithromycin could comparably down-regulate the mRNA expression of CD86 (Fig. 7b) and OX40 ligand (OX40L) (Fig. 7d) in sinonasal mucosa from CRSsNP and eosinophilic CRSwNP patients, whereas no statistically significant effect was observed for sinonasal mucosa from non-eosinophilic CRSwNP patients. This evidence concerns the gene TNFSF4 and chronic rhinosinusitis without nasal polyps.