Abstract
Abstract Objective Chronic rhinosinusitis with nasal polyps (CRSwNP) is a multifactorial disorder characterized by heightened and sustained inflammation. A20 is a novel multifunctional protein with immunomodulatory effects. We sought to investigate the expression of A20 in sinonasal mucosa, and its association with local inflammation and disease severity in patients with CRSwNP. Methods The expression of A20 in sinonasal samples was assessed by quantitative RT-PCR, IHC, and Western blot. The numbers of local inflammatory cells were counted. CT scan findings and symptom severity were scored. Primary nasal epithelial cells were cultured to explore the regulation of A20 expression. Results Compared with control tissues and non-eosinophilic polyps, the mRNA and protein expression of A20 was significantly down-regulated in eosinophilic polyps. A20 was mainly expressed by epithelial cells. The expression of A20 in nasal epithelial cells was significantly reduced in eosinophilic polyps in comparison with those in non-eosinophilic polyps and control tissues. There was a further decrease in A20 expression in nasal epithelial cells in patients with eosinophilic polyps with asthma compared to those without asthma. A20 mRNA was induced by TNF-α, LPS, dsRNA, and dexamethasone, whereas was inhibited by IL-4 and IL-13 in human primary nasal epithelial cells. A20 mRNA levels in nasal epithelial cells negatively correlated with IL-4 and IL-13 levels and eosinophil numbers in sinonasal mucosa. Importantly, mRNA levels of A20 in nasal epithelial cells negatively correlated with disease duration and so on. Conclusions The decreased expression of A20 might contribute to eosinophilic inflammation and disease progression in patients with CRSwNP.