Possible role of transforming growth factor beta and interleukin-4 in the up-regulation of CLC-2 and CLC-3 in chronic rhinosinusitis.

Background: Chronic rhinosinusitis (CRS) may cover different disease entities, and the pathogenic mechanism remains unclear.

Methods: The aim of this study was to evaluate the expression of chloride channel protein CLC-2 and CLC-3 in CRS without nasal polyps (CRSsNP) and evaluate the roles of interleukin (IL)-4 and transforming growth factor (TGF) beta in the up-regulation of CLC-2 and CLC-3. We detected expression of CLC-2 and CLC-3 in 17 patients with CRSsNP by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR), and we examined the concentration of TGF-beta, IL-4, IL-5, and interferon (IFN) gamma in ethmoid sinus mucosa by enzyme-linked immunosorbent assay (ELISA).

Results: We found that CLC-2 and CLC-3 is up-regulated in CRSnNP and located in submucosal glands and epithelium of the ethmoid sinus. CLC-2 and CLC-3 mRNA correlated with IL-4 in CRSsNP (r = 0.57 and 0.65; p < 0.05). CLC-2 and CLC-3 mRNA correlated negatively with mucosal TGF-beta in CRSsNP (r = -0.49 and -0.54; p < 0.05).

Conclusion: We concluded that CLC-2 and CLC-3 is up-regulated in ethmoid mucosa and may affect the development of CRSsNP. TGF-beta and IL-4 may modulate the expression of CLC-2 and CLC-3 in CRSsNP.