[Expression of B7-H1/PD-1 in mucosa of chronic rhinosinusitis].

OBJECTIVE: To explore the expression of B7-H1/PD-1 and the localization of these proteins in human sinus mucosa of chronic rhinosinusitis (CRS). METHODS: Twenty-eight patients with CRS (17 with nasal polyps (CRSwNP) and 11 without (CRSsNP)) and 11 control patients were recruited. B7-H1/PD-1 expressions in sinus mucosa among these 3 groups were detected by immunofluorescent staining, real-time quantitative PCR and Western blot. Flow cytometry was also employed to identify the type of B7-H1 or PD-1 positive cells in nasal polyps. RESULTS: Compared with normal mucosa, B7-H1/PD-1 mRNA was highly expressed in sinonasal mucosa of CRSwNP and CRSsNP (P < 0.01). There was no difference between CRSwNP and CRSsNP (P > 0.05). The protein level of B7-H1/PD-1 was similar to mRNA level. As indicated by immunofluorescent assay, B7-H1 was mainly expressed in sinonasal epithelial cells, submucosal gland cells and inflammatory cells within the subepithelial layer while PD-1 was expressed in inflammatory cells within the subepithelial layer. The B7-H1 or PD-1 positive cells in nasal polyps were partially CD19+ B cells and CD3+ T cells respectively. CONCLUSION: B7-H1/PD-1 is up-regulated in sinus mucosa of CRS. B7-H1/PD-1 may play an important role in the pathogenesis of CRS.