CXCL8 and chronic rhinosinusitis with nasal polyps: Li et al. found that methylation levels at CpG sites in the proximal promoter region of IL-8 were significantly decreased in NP of CRSwNP vs. ethmoid tissue of CRSsNP and ITM of control subjects, and this also correlated with IL-8 levels on ELISA, which were higher in CRSwNP vs. CRSsNP and controls (24).