Immunoregulatory role of saliva polymeric IgA1 in the pathogenesis of primary Sjögren’s Syndrome

项目摘要/摘要 到目前为止，原发性干燥综合征(PSS)的发病机制尚不清楚，导致3至6年 初次诊断延迟。血清抗Ro/SSA自身抗体和活检病灶评分是两个关键分类 2016年ACR-EULAR1的PSS标准。文献表明，活检病灶评分为正 与轻微唾液腺纤维化相关的区域，组织损伤的常见后果和 炎症2，3.尚不清楚是组织驻留的淋巴细胞浸润还是抗Ro/SSA自身抗体 启动自身免疫组织破坏和精心策划的PSS疾病进展。这项建议是为了 探讨唾液抗Ro52/SSA抗体与唾液腺组织破坏的相关性。 我们开发了一种基于唾液的电化学检测、电场诱导释放和测量 (EFIRM)，可以筛查、早期检测、风险评估PSS的发病，替代目前的基于血液的ELISA 血清学检测。初步数据表明：1)EFIRM可以直接检测和定量唾液抗-HBs PSS患者中Ro52/SSA自身抗体；2)PSS和SICA患者唾液和血清中抗Ro/SSA相关 唾液抗Ro52/SSA IgA1抗体与唾液腺病灶积分相关。IGA以两种同种类型存在， IgA1和IgA2，以及IgA1可进一步细分为单体(MIgA1)和聚合物(PIgA1)亚类4，5。 人血清IgA1主要以单体形式存在(85%-90%)，而唾液分泌型IgA1主要存在 聚合型免疫球蛋白受体(PIgR)分泌的聚合型(90-95%)。单体和聚合物免疫球蛋白A1是 由于mIgA1中存在半乳糖，而pIgA14、6、7中没有半乳糖，所以结构上的不同。 MIgA1中半乳糖的含量可以用半乳糖特有的豆科植物凝集素--鸡冠花凝集素来检测 (ECL)8，而pIgA1可用N-乙酰半乳糖胺结合凝集素Helix pomatia凝集素检测 (HPA)9.除了结构上的差异外，mIgA1和pIgA1还表现出不同的免疫调节作用 免疫抑制因子5，7，诱导因子10。我们推测PSS患者唾液中存在pIgA1抗Ro52/SSA抗体 患者与唾液腺组织破坏有关，通过活检病灶评分来衡量。 为了检验这一假说，本文提出了两个具体目标。目标1是开发基于唾液的抗Ro52 mIgA1和 PIgA1免疫分析。目的2检测PSS、SICCA和对照组唾液中抗Ro52mIgA1和pIgA1抗体 目的探讨唾液中pIgA1与唾液腺纤维化和破坏的关系。在未来的研究中 计划，我们将调查唾液pIgA1抗Ro52/SSA和组织驻留免疫T细胞之间的串扰 Helper 17细胞12-14。我们的研究旨在确定唾液自身抗体，抗Ro52/SSA的作用 聚合的IgA1，与PSS患者的唾液腺破坏有关。

PROJECT SUMMARY/ABSTRACT To date, the pathogenesis of primary Sjögren’s Syndrome (pSS) is not well understood resulting in a 3 to 6 year delayed initial diagnosis. Serum anti-Ro/SSA autoantibodies and biopsy focus score are two key classification criteria of pSS by the 2016 ACR-EULAR1. Literature demonstrated that biopsy focus score is positively associated with the area of minor salivary gland fibrosis, common consequence of tissue damage and inflammation2,3. It is unclear whether tissue-resident lymphocyte infiltration or anti-Ro/SSA autoantibodies initiated autoimmune tissue destruction and orchestrated pSS disease progression. This proposal is to investigate the crosstalk between salivary anti-Ro52/SSA and salivary gland tissue destruction. We have developed a saliva-based electrochemical assay, electric field-induced release and measurement (EFIRM), that can screen, earlier detect, risk assess onset of pSS, alternative to the current ELISA blood-based serology assay. Preliminary data demonstrated: 1) EFIRM can directly detect and quantify salivary anti- Ro52/SSA autoantibodies in pSS patients; 2) Salivary and serum anti-Ro/SSA are correlated in pSS and Sicca patients; 3) Salivary anti-Ro52/SSA IgA1 correlate to salivary gland focus scores. IgA exists in two isotypes, IgA1 and IgA2, and IgA1 can further be subdivided into monomeric (mIgA1) and polymeric (pIgA1) subclasses4,5. Human serum IgA1 mostly exists as monomeric form (85-90%) whereas saliva secretory IgA1 are predominantly polymeric form (90-95%) secreted by polymeric Ig receptor (pIgR). Monomeric and polymeric IgA1 are structurally different due to the presence of galactose in the mIgA1, and absence in the pIgA14,6,7. The presence of galactose in mIgA1 can be detected using the galactose-specific legume lectin, Erythrina cristagalli lectin (ECL)8 whereas pIgA1 can be detected using the N-acetylgalactosamine binding lectin, Helix pomatia agglutinin (HPA)9. In addition to structural differences, mIgA1 and pIgA1 also exhibit differential immunoregulatory roles as immune suppressor5,7 and inducer10 respectively. We hypothesize that salivary pIgA1 anti-Ro52/SSA in pSS patients is associated with salivary gland tissue destruction, measured by biopsy focus score. Two Specific Aims are proposed to test this hypothesis. Aim 1 is to develop saliva-based anti-Ro52 mIgA1 and pIgA1 immunoassays. Aim 2 is to measure anti-Ro52 mIgA1 and pIgA1 in saliva of pSS, Sicca, and control subjects to investigate the correlation of saliva pIgA1 to salivary gland fibrosis and destruction. In future research plan, we will investigate the crosstalk between salivary pIgA1 anti-Ro52/SSA and tissue-resident immune T helper 17 cells12–14. Our studies are intended to determine the role of salivary autoantibody, anti-Ro52/SSA polymeric IgA1, in the context of salivary gland destruction in pSS patients.