The expression of epithelial intercellular junctional proteins in the sinonasal tissue of subjects with chronic rhinosinusitis: a histopathologic study.

To evaluate the expression of five epithelial intercellular junctional proteins in the sinonasal tissue of subjects with chronic rhinosinusitis (CRS). Forty-one samples of nasal polyp tissue of CRS patients with nasal polyps (wNP), 20 ethmoid sinus mucosa of CRS patients without nasal polyps (sNP) and 19 nasal mucosa of controls were collected and assessed for the expression of zonulae occludens (ZO-1), claudin-1, E-cadherin and desmoglein-1 and -2 (DSG1, DSG2) using immunohistochemical staining. Interleukin (IL)-5, IL-6 and IL-8 concentrations in the tissues were also measured using ELISA. The expression of ZO-1, claudin-1, DSG1 and DSG2 in the CRSwNP patient group and the expression of claudin-1, DSG1 and DSG2 of the CRSsNP patient group was significantly lower compared to that of the control group. Furthermore, the expression of DSG1 in the CRSwNP patient group was also significantly lower than in the CRSsNP patient group. In contrast, the expression of E-cadherin in the CRSwNP and the CRSsNP patient groups was significantly greater compared to the controls. The assessment of associations between the expression of the intercellular junctional proteins and cytokines demonstrated negative correlations between IL-5 and claudin-1, IL-6 and claudin-1, IL-6 and DSG2, IL-8 and DSG1, and IL-8 and DSG2. In contrast, a positive correlation was found between IL-8 and E-cadherin. Differences in the expression of epithelial intercellular junctional proteins may play an important role in the pathogenesis of CRS.