[Cytokines of nasal inverted papilloma: quantification and distribution]

We previously found that an increased number of mucosal mast cells accumulated in the tumor site of nasal inverted papilloma as well as in the epithelial layer of the allergic nasal mucosa. However, the mechanism of accumulation of mucosal mast cells has not yet been clarified. The purpose of this study was to evaluate the cytokines produced by inverted papilloma cells, which would be important for the accumulation of mucosal mast cells. We found that the supernatant of the monolayer of cultured inverted papilloma cells contained GM-CSF, IL-6 and IL-8. IL-2, IL-3, IL-4 and IL-5 were not detected. Contrary to the quantities of cytokines detected in the supernatant of cultured allergic nasal epithelial cells, the quantities of IL-6 and IL-8 were greater in the supernatant of cultured inverted papilloma, whereas that of GM-CSF was less. Immunohistochemical study revealed the distribution of cytokines: GM-CSF was detected near the basement membrane of the tumor site, while IL-6 and IL-8 were detected in the superficial layer of nasal inverted papilloma. Interestingly, the tumor site near the basement membrane is also the site of accumulation of mucosal mast cells, suggesting that GM-CSF produced by nasal inverted papilloma cells may be one of the most important factors in the accumulation of mucosal mast cells.