Upregulation of elafin and cystatin C in the ethmoid sinus mucosa of patients with chronic sinusitis

Objectives: To investigate the expression levels and distribution patterns of elafin and cystatin C in normal and inflammatory human sinus mucosa and to evaluate their roles in chronic sinusitis. Design: A controlled, prospective study. Setting: A tertiary academic institution. Patients: Normal sinus mucosa was obtained from the ethmoid sinus during surgery in 30 patients with blowout fractures. Inflammatory sinus mucosa was obtained from 30 patients undergoing endoscopic sinus surgery for chronic polypoid sinusitis. Interventions: Reverse transcription - polymerase chain reaction, immunohistochemical analysis, and Western blotting. Main Outcome Measures: Expression levels and distribution patterns of elafin and cystatin C in normal and inflammatory mucosa. Results: Expression of elafin and cystatin C messenger RNAs and proteins analyzed by means of reverse transcription-polymerase chain reaction and Western blot was detected in all normal and inflammatory sinus mucosa tested. Their expression levels were increased in inflammatory vs normal mucosa. Elafin in normal and inflammatory sinus mucosa was distinctly expressed in goblet cells, which are increased in inflammatory sinus mucosa. Elafin in submucosal glands was usually weak in staining intensity, except for a few scattered submucosal glands showing moderate intensity in inflammatory sinus mucosa. Cystatin C was also localized in goblet cells and submucosal glands in normal and inflammatory mucosa. Staining intensity was increased more in inflammatory vs normal sinus mucosa. Conclusion: Elafin and cystatin C may play an important role in the protection of normal sinus mucosa and further in regulation of the inflammatory condition in chronic sinusitis.