Abstract
PURPOSE: Whereas the majority of nasal polyps observed in Western populations are eosinophilic, non-eosinophilic nasal polyps are significantly more frequent in Asian countries. Given the importance of nuclear factor-kappa B (NF-κB) in inflammation, this study focused on the role of NF-κB in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNPs) in Asian patients. METHODS: A total of 46 patients were enrolled in this study (22 diagnosed with CRSwNPs, 10 with chronic rhinosinusitis without nasal polyps [CRSsNP], and 14 control subjects). Nasal polyps and uncinate tissues (UTs) were collected and the tissues prepared for hematoxylin-eosin staining and immunohistochemistric (IHC) analysis. Total RNA was isolated for real-time polymerase chain reaction for p65, interleukin (IL)-6, IL-8, intracellular adhesion molecule (ICAM)-1, IL-1β, tumor necrosis factor (TNF)-α, and eotaxin. RESULTS: In the CRSwNPs group, 50% of nasal polyps were non-eosinophilic. IHC revealed a significantly higher fraction of NF-κB p65-positive cells in nasal polyps of the CRSwNPs group than in the UTs of control and CRSsNP groups. No difference in NF-κB p65-positive cell fraction was observed between eosinophilic and non-eosinophilic nasal polyps. The mRNA expression of p65, IL-6, IL-8, and eotaxin was significantly higher in nasal polyps of the CRSwNPs than in the UTs of control and CRSsNP group. However, no difference in expression was observed between eosinophilic and non-eosinophilic nasal polyps, with the exception of IL-1β expression. CONCLUSIONS: Elevated expression of NF-κB- and NF-κB-associated inflammatory cytokines suggests NF-κB as the key factor for CRSwNPs pathogenesis in Asian patients. Understanding NF-κB-associated mechanisms will provide a deeper insight into CRSwNPs pathogenesis and ultimately improve therapeutic strategies for CRSwNPs.