Dysbiotic oral microbiota in patients with Sjogren’s syndrome

Sjogren’s syndrome (SS) is a systemic autoimmune disorder characterized by dryness of the mouth and eyes. Lymphocytic sialadenitis is a key event for the development of SS, but its pathogenic mechanism is not clear. The aim of this study is to investigate a potential role of oral microbiota in the pathogenesis of SS. Metagenomic analysis of oral microbiota collected from healthy individuals (n = 15), drug-induced sicca patients (n = 10), and SS patients (n = 25) revealed an increased Shanon diversity in SS. Although a substantial part of the changes in the oral microbiota of SS was shared in that of drug-induced sicca, SS-specific changes were also observed. Particularly, an increase in the relative abundance of Prevotella melaninogenica (Pm) was associated with SS (Odd Ratio 5.4, p = 0.003), but not with dryness, by logistic regression analysis. In contrast to commensal oral species, Pm upregulated the expression of MHC molecules, CD80, and CD86 from human submandibular gland tumor (HSG) cells in vitro.

干燥综合征（Sjogren’s syndrome, SS）是一类以口眼干燥为主要特征的全身性自身免疫性疾病。淋巴细胞性涎腺炎（Lymphocytic sialadenitis）是干燥综合征发病进程中的关键事件，但其具体致病机制仍未明确。本研究旨在探讨口腔微生物群（oral microbiota）在干燥综合征发病机制中的潜在作用。研究对健康受试者（n=15）、药物性干燥患者（n=10）及干燥综合征患者（n=25）的口腔微生物群开展宏基因组分析（metagenomic analysis），结果显示干燥综合征患者的口腔菌群香农多样性指数显著升高。尽管干燥综合征患者口腔菌群的改变有相当一部分与药物性干燥患者的菌群变化重叠，但同时也观察到干燥综合征特异性的菌群改变。经logistic回归分析证实，产黑色素普雷沃菌（Prevotella melaninogenica, Pm）的相对丰度升高与干燥综合征显著相关（比值比5.4，p=0.003），而与口干眼干的症状无关联。与口腔共生菌群不同的是，体外实验显示产黑色素普雷沃菌可上调人下颌下腺肿瘤（HSG）细胞的MHC分子、CD80及CD86的表达。