THU0104 THE GUT MICROBIOTA AND ITS RELEVANCE TO PERIPHERAL T REGULATORY CELLS AND T HELPER 17 IN PATIENTS WITH RHEUMATOID ARTHRITIS
Authors: Y. LI, S. X. Zhang, X. F. Yin, Z. Mingxing, J. Luo, G. Y. Liu, C. Gao, X. Li
Journal: Annals of the Rheumatic Diseases (2020)

Background: Rheumatoid arthritis (RA) is a common autoimmune disorder with joint destruction and synovial inflammation characterized by abnormal immune responses to autoantigens. Our previous studies have demonstrated that impaired peripheral lymphocytes especially insufficiency of regulatory T cells (Tregs) played an important role in pathogenesis of RA 1 2 . Interestingly, the dysbiosis of gut microbiota triggers several types of autoimmune diseases through the imbalance of T lymphocyte subsets 3 . However, the detailed gut microbiota of RA patients and its correlation with Tregs and helper T cells 17 (Th17) are unclear up until now. Objectives: To compare the difference of gut microbiota between RA and healthy controls (HCs), and to investigate the relevance of gut microbiota with circulating Tregs and Th17 in patients with RA. Methods: From December 2018 to August 2019, a total of 205 diagnosed patients with RA and 199 age and sex-matched HCs were enrolled in this study. Stool of Every participant was collected for bacterial DNA extraction and 16S ribosomal RNA (rRNA) gene sequencing. The absolute numbers of Tregs and Th17 in PB of these individuals were measured by Flow Cytometer (FCM) combined with standard absolute counting beads. Data were expressed as mean ± standard deviation to the distribution. Independent-samples T test and Spearman rank correlation test. P value &lt;0.05 were considered statistically significant. Results: Patients with RA had a significantly difference of diversity and abundance of intestinal microbiota compared with those of HCs (P&lt; 0.05). Detailedly, the abundance of Proteobacteria was significantly increased in RA patients (P&lt; 0.05), and the abundance of Firmicutes, Fusobacteria and Verrucomicrobia were significantly reduced (P&lt;0.05) at the level of Phylum (Figure 1). At the genus level, in the RA group, the abundance of Escherichia, Ruminococcus2 and Clostridium_sensu_stricto were significantly increased (P&lt; 0.05), but the abundance of Lachnospiracea_incertae_sedis, Prevotella, Clostridium_XlVa, Roseburia, Dialister, Blautia, Megamonas and Gemmiger were significantly lower than the healthy controls (P&lt; 0.05) (Figure 2). Moreover, Blautia, Anaerostipes and Ruminococcus2 have negative correlation with the absolute number of Tregs, and Cloacibacillus and Streptophyta have positive correlation with the absolute number of Th17. Conclusion: Patients with RA had a dysbiosis of the gut microbiota in both diversity and abundance, which is closely related to the impaired peripheral lymphocyte subsets, that may be related to the pathogenesis of RA, which might provide a new idea for RA treatment. References: [1]Wen HY, Wang J, Zhang SX, et al. Low-Dose Sirolimus Immunoregulation Therapy in Patients with Active Rheumatoid Arthritis: A 24-Week Follow-Up of the Randomized, Open-Label, Parallel-Controlled Trial. J Immunol Res 2019;2019:7684352. doi: 10.1155/2019/7684352 [published Online First: 2019/11/30] [2]Niu HQ, Li ZH, Zhao WP, et al. Sirolimus selectively increases circulating Treg cell numbers and restores the Th17/Treg balance in rheumatoid arthritis patients with low disease activity or in DAS28 remission who previously received conventional disease-modifying anti-rheumatic drugs. Clin Exp Rheumatol 2019 [published Online First: 2019/05/11] [3]Lee N, Kim WU. Microbiota in T-cell homeostasis and inflammatory diseases. Exp Mol Med 2017;49(5):e340. doi: 10.1038/emm.2017.36 [published Online First: 2017/05/27] Acknowledgments: None Disclosure of Interests: None declared