Background: Many kinds of inflammatory cells and cytokines are suggested to be related with pathophysiology of CRSwNP, but not yet fully understood. In particular, little is known about the function and role of IL-10 producing regulatory B cells.
Objectives: The aim of this study was to compare the clinical characteristics of chronic sinusitis patients with nasal polyps by histologic findings and to compare the clinical features. We also investigated the presence and function of B cells, especially IL-10-producing regulatory B cells, in the nasal polp and nasal mucosa in each group.
Methods: 20 patients with CRSwNP, 10 patients with chronic rhinosinusitis without NP (CRSsNP) and 10 control subjects were enrolled in this study. NP tissues and uncinate tissues (UT) were collected for analysis. Real-time PCR, immunohistochemistry were performed to measure the expression levels of the selected inflammatory cytokines and inflammation-associated molecules.
Results: In the mucosal tissues of CRSsNP patients, the number of IL-10 + B cells was significantly lower than that of nasal polyp and control mucosa of CRSwNP patients. The numbers of IL-10 + B cells were significantly increased in the eosinophilic nasal polyp, non-eosinohilic nasal polyp, CRSsNP, and control groups. There was a significant positive correlation between the number of IL-10 + B cells and BAFF.
Conclusion: The expression of IL-10 + B cells and BAFF was significantly increased in CRSwNP patients compared to CRSsNP patients and control mucosal tissues, and IL-10 + B cells were more significantly increased in eosinophilic tissues . These results indicate that regulatory B cells are involved in the pathophysiology of eosinophilic nasal polyp and that BAFF contributes to the production of regulatory B cells.