Increased expression of glycoprotein 340 in the ethmoid sinus mucosa of patients with chronic sinusitis

Objectives: To investigate the expression and distribution of glycoprotein 340 (gp340), a secretory glycoprotein, in normal human sinus mucosa and inflammatory sinus mucosa and evaluate the possible effects of gp340 on the development of chronic sinusitis. Glycoprotein 340 was identified as a key element in the innate host defense mechanism on many mucosal surfaces and is directly involved in defense functions aimed at clearing gram-positive and gram-negative bacteria. Design: Prospective study. Setting: Tertiary academic institution. Patients: Normal sinus mucosa was obtained from the ethmoid sinus mucosa of 8 patients with blowout fractures undergoing endoscopic reduction. Inflammatory sinus mucosa was taken from 25 patients with chronic polypoid sinusitis during endoscopic sinus surgery. Intervention: Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemical analysis, and Western blotting were performed. Main Outcome Measures: The expression level and distributional pattern of gp340 in normal and inflammatory sinus mucosa were analyzed. Results: Transcripts of the gp340 gene were detected in all human sinus tissues analyzed by RT-PCR. Immunohistochemical analysis revealed that gp340 is mainly localized in submucosal gland of both normal and inflammatory sinus mucosa. Semiquantitative RT-PCR and Western blot analysis showed the increased expression levels of gp340 in the inflammatory sinus mucosa compared with the normal sinus mucosa. Conclusion: These results suggest that gp340 may play a constitutive role in nasal defense and may be upregulated in response to inflammation, participating in antimicrobial defense in chronic sinusitis.