Nuclear Factor‐Kappa B Activation in the Nasal Polyp Epithelium: Relationship to Local Cytokine Gene Expression

AbstractObjectives A panel of cytokines has been found to be important for eosinophil accumulation and activation in nasal polyps. The aims of this study were to ascertain whether the activation of nuclear factor‐kappa B (NF‐κB) occurred in the polyp epithelium, and to examine the relationship between the degree of activation and local cytokine gene expression.Study Design/Methods: Nasal polyp specimens were obtained from 26 untreated patients. The proportion of nuclear translocation of the NF‐κB p50 subunit in the polyp epithelium was quantitatively analyzed by a combination of fluorescent immunohistochemistry and a laser scanning confocal microscope image system. The levels of GM‐CSF, IL‐5, IL‐8, IL‐16, and eotaxin mRNA expression in the same speci‐mens were measured using reverse transcription‐polymerase chain reaction.Results Both cytoplasmic and nuclear localization of the p50 subunit was observed mainly in the epithelial layer in all specimens. The percentages of epithelial cells with nuclear translocation ranged from 4.5% to 40.5% (median, 18%). Significant correlations were observed between the degree of epithelial NF‐κB activation and the levels of IL‐8, IL‐16, and eotaxin mRNA expression (r = 0.468, 0.47, and 0.739, respectively).Conclusion The activation of NF‐κB in the nasal polyp epithelium is responsible for the recruitment of inflammatory cells, particularly eosinophils, through the initiation of the transcriptional pathway of the related cytokines. The increased NF‐κB activity in the polyp epithelium may reflect hypersensitivity to unknown stimuli.