목적: Vitamin D (VD) is a steroid hormone regulating innate immunity. VD activating (CYP27A1, CYP27B1) and inactivating (CYP24A1) enzymes are responsible for the synthesis of the active 1,25- dehydroxyvitamin D3. Considering the evidence that chronic rhinosinusitis is associated with deranged innate immunity, the expression of VD-metabolizing enzymes may play a role in the pathogenesis of chronic rhinosinusitis (CRS). The present study is to investigate the expression and distribution pattern of Vitamin D receptor (VDR) and VD-metabolizing enzyme in normal and inflammatory sinus mucosa, and elucidate the effect of CRS- relevant Th1 and Th2 cytokines on their expression levels. 방법:The expression levels and distribution pattern of VDR, CYP27A1, CYP27B1, and CYP24A1 were evaluated in the normal ethmoid sinus mucosa of healthy controls and inflammatory sinus mucosa of patients with CRS with or without nasal polyps by RT-PCR, real time PCR, immunohistochemistry, and western blot. The effect of Th1 and Th2 cytokines on the expression of VDR and VD metabolizing enzymes was evaluated using cultured epithelial cells. The measurement of vitamin D levels was done by ELISA. 결과:VDR and VD metabolizing enzymes were expressed in normal and inflammatory sinus mucosa where they are consecutively distributed in the epithelial cells, submucosal glands, and vascular endothelium. The expression levels of CYP27A1, and CYP27B1 were increased in inflammatory sinus mucosa, while VDR and CYP24A1 levels are decreased. VD levels were increased in inflammatory sinus mucosa. Th1 and Th2 cytokines induced increased levels of VD activating enzymes and decreased levels of VD inactivating enzymes. 결론:The present results showed that VDR and VD metabolizing enzymes are expressed in normal and inflammatory sinus mucosa, suggesting that VD may be produced in sinus mucosa and VD may play a role in the pathogenesis of chronic rhinosinusitis.