AB0535 Effect of metformin on the absolute number of cd4+ t cell subsets in patients with primary sjogren’s syndrome
Authors: X. Sun, H. Yao, J. He, G. Chai, L. Wei, J. Xie, C. Gao, X. Li, J. Li
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Primary Sjogren's syndrome is a chronic inflammatory autoimmune disease characterised by the infiltration of lymphocytes into exocrine glands such as the salivary gland and lacrimal gland. Although its etiology and pathogenesis is unclear at present, we consider immune dysfunction plays a significant role in the process. A lot of studies have confirmed that the formation of Treg and Th17 cells interact between each other, and their balance can affect the immune response results, notably reflected in various autoimmune and inflammatory diseases, including primary Sjogren's syndrome. However, there are few studies on the absolute number of CD4 +T cells in peripheral blood of patients with primary Sjogren's syndrome. In addition, metformin can affect the balance of Th17/Treg cells through the AMPK-mTOR pathway. <h3>Objectives</h3> To explore whether metformin can affect the balance of Th17/Treg cells in peripheral blood of patients with primary Sjogren's syndrome, and then be applied in the treatment of pSS patients. <h3>Methods</h3> The number of Treg cells{28.74 (21.22,38.68) vs 34.05 (30.14,42.31),P=0.023}significantly increased after the treatment. At the same time, there was a significantly decrease in the ratio of h17/Treg cells{0.25 (0.08,0.44) vs 0.18 (0.04,0.32),P=0.014},]. Besides, after the treatment the absolute number of Th17 cells were increased, but it was not statistically significant{4.5 (3.64,14.23) vs 7.87 (2.37,19.89),P=0.835}. In addition, the clinical symptoms of the metformin group were obviously improved, while the dosage of prednisone, leflunomide or hydroxychloroquine reduced significantly. <h3>Results</h3> The number of Treg cells{28.74 (21.22,38.68) vs 34.05 (30.14,42.31),P=0.023}significantly increased after the treatment. At the same time, there was a significantly decrease in the ratio of h17/Treg cells{0.25 (0.08,0.44) vs 0.18 (0.04,0.32),P=0.014},]. Besides, after the treatment the absolute number of Th17 cells were increased, but it was not statistically significant{4.5 (3.64,14.23) vs 7.87 (2.37,19.89),P=0.835}. In addition, the clinical symptoms of the metformin group were obviously improved, while the dosage of prednisone, leflunomide or hydroxychloroquine reduced significantly. <h3>Conclusions</h3> Metformin can increase the absolute number of Treg cells and decrease the ratio of Th17/Treg cells in the peripheral blood of patients with pSS, while reducing the use of hormones and DMARDs drugs. And it may be one of the mechanisms adopted in the treatment for pSS. <h3>References</h3> [1] Matsui K, Sano H. T Helper 17 Cells in Primary Sjogren's syndrome [J]. Journal of Clinical Medicine2017;6(7):65. [2] Saito M, Otsuka K, Ushio A, et al. Unique Phenotypes and Functions of Follicular Helper T Cell and Regulatory T Cell in Sjogren's Syndrome. [J] Curr Rheumatol Rev2017;13(999). [3] Lee SY, Moon SJ, Kim EK, et al. Metformin Suppresses Systemic Autoimmunity in Roquin (san/san) Mice through Inhibiting B Cell Differentiation into Plasma Cells via Regulation of AMPK/mTOR/STAT3[J]. Journal of Immunology2017;198(7):2661. <h3>Disclosure of Interest</h3> None declared