Treg and Th17 cells in inflammatory periapical disease: a systematic review

Abstract: The process involved in periapical lesions, which occur as an outcome of pulpal necrosis, is regulated by the immune system including regulatory T cells (Treg) and T helper 17 cell (Th17) responses. The objective of this study was to conduct a frequency systematic review to determine the presence of Treg/Th17 responses and the influence of these cells in the progression of chronic inflammatory periapical lesions in humans. A systematic computerized search was carried out in Pubmed, Medline, Web of Science and Scopus electronic databases from their date of inception through the first week of May 2017. In addition, the reference lists of the included articles and the grey literature were hand-searched. Articles that evaluated the presence and influence of Treg/Th17 in the progression of human periapical lesions were included. Study selection and the quality assessment of the included articles (using the Newcastle-Ottawa scale) were carried out by two authors. Fifty-seven titles/abstracts were screened and eight studies met the eligibility criteria and were included in this systematic review. The included studies showed large variation in the type of periapical lesion assessed, mean age, age range, type of experiment and findings regarding the participation of Th17 and Treg in the status of inflammatory periapical lesions. The studies showed the involvement of Treg in the modulation of the inflammatory response in radicular cysts and periapical granulomas. This systematic review highlights the relationship between Treg and Th17 acting in a subtle balance inhibiting or promoting the progression of human periapical lesions.

摘要：根尖周病变是牙髓坏死的继发结局，其发生发展过程受免疫系统调控，其中涉及调节性T细胞（regulatory T cells, Treg）与辅助性T细胞17（T helper 17 cell, Th17）的免疫应答。本研究旨在开展频次型系统综述，明确人类慢性炎症性根尖周病变进展过程中Treg/Th17免疫应答的存在情况，以及此类细胞对病变进展的影响。研究通过计算机系统检索PubMed、Medline、Web of Science及Scopus电子数据库，检索时限自建库至2017年5月第一周；此外还手工检索了纳入文献的参考文献列表及灰色文献。本研究纳入的文献需评估Treg/Th17在人类根尖周病变进展中的存在情况与影响。由两名研究者独立完成文献筛选及纳入研究的质量评价，评价工具采用纽卡斯尔-渥太华量表（Newcastle-Ottawa scale）。本研究共筛选57篇题录/摘要，最终有8项研究符合纳入标准并被纳入本次系统综述。纳入的研究在所评估的根尖周病变类型、平均年龄、年龄跨度、实验类型，以及Th17与Treg在炎症性根尖周病变状态中的参与相关结果等方面均存在较大异质性。现有研究表明，Treg参与调控根尖周囊肿与根尖周肉芽肿的炎症应答。本次系统综述揭示，Treg与Th17通过微妙的平衡关系发挥调控作用，分别抑制或促进人类根尖周病变的进展。