CD80 and congenital rubella syndrome: Both dexamethasone and clarithromycin could down-regulate the mRNA expression of CD80 (Fig. 7a), inducible costimulator ligand (ICOSL) (Fig. 7c) and programmed cell death ligand 1 (PD-L1) (Fig. 7e) in sinonasal mucosa from all three CRS groups in similar extent.