Methods: A total of 81 patients (45 with non-eosinophilic nasal polyps and 36 with eosinophilic nasal polyps) were enrolled. Clinical information and computed tomography (CT), endoscopic, and histological findings were investigated. Tissue samples were analyzed for total IgE protein concentration levels and for mRNA expression levels of interleukin (IL)-4, IL-5, IL-13, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IL-17A, IL-22, IL-23p19, transforming growth factor (TGF)-β1, TGF-β2, TGF-β3, and periostin. Immunostaining assessment of Ki-67 as a proliferation marker was performed.
Results: Non-eosinophilic CRSwNP showed greater localized and maxillary involvement but lesser olfactory involvement on CT in early stage disease compared with eosinophilic CRSwNP. In addition, ethmoidal/maxillary CT scores, indicating ethmoidal dominant involvement, were positively correlated with levels of TH2 inflammatory markers, such as IL-5, periostin mRNA expression and total IgE levels in nasal polyp (NP) tissues, whereas scores were inversely correlated with levels of the TH1 cytokine, IFN-γ. In non-eosinophilic NPs, Ki-67 expression was upregulated, especially in epithelia. Additionally, epithelial ingrowing patterns such as pseudocysts were more frequently observed in histologic and endoscopic evaluations of non-eosinophilic NPs compared with eosinophilic NPs. A criterion combining the cutoff level (2,167) of ethmoidal/maxillary CT scores and the presence of pseudocysts on endoscopic examination yielded a sensitivity of 100.0% and a specificity of 71.0% for the diagnosis of non-eosinophilic CRSwNP.
Conclusion: We demonstrate that the combination of ethmoidal/maxillary CT scores and the presence of pseudocysts by endoscopy may be used as a surrogate marker to distinguish non-eosinophilic CRSwNP from eosinophilic CRSwNP in Asian patients.