シェーグレン症候群の病態形成におけるCXCL10の役割

Sjögren's syndrome (SS) is a common autoimmune disease characterized by the destruction of acinar structure by marked lymphocytic infiltrates in the salivary and lacrimal glands, resulting in sicca symptoms. Gene expression profiling of lip salivary glands (LSGs) shows that C-X-C motif chemokine 10 (CXCL10) expression is upregulated in patients with primary SS (pSS). CXCL10 and its receptor, C-X-C receptor 3 (CXCR3), contribute to the pathogenesis of SS. We investigated the clinical significance of CXCL10 and CXCR3 in the autoimmune lesions of pSS and the molecular mechanisms of CXCL10 upregulation in the salivary gland cells. CXCL10 showed particularly intense staining in LSG ductal cells from pSS patients. CXCR3 expression was detected primarily in CD163+ macrophages. The number of CXCR3+CD163+ macrophages was inversely correlated with the severity of LSG inflammatory lesions. Our in vitro experiments demonstrated that human salivary gland ductal (NS-SV-DC) cells produced higher levels of CXCL10 than acinar (NS-SV-AC) cells. Furthermore, NS-SV-DC and NS-SV-AC cells had different regulators of CXCL10 enhancement: interferon (IFN)-γ had more potential than IFN-α, tumor necrosis factor (TNF)-α, and interleukin (IL)1-β in the induction of CXCL10 production in NS-SV-DC cells, whereas TNF-α had the potential to induce CXCL10 production in NS-SV-AC cells. Our results suggest that CXCL10 overexpression in salivary glands is mainly caused by IFN-γ-stimulated salivary gland ductal cells. The enhanced production of CXCL10 by ductal cell IFN-γ results in the migration of CXCR3+ immune cells. CXCL10 plays an important role in SS pathogenesis, and CXCL10 regulation may be useful in the treatment of SS patients.