AB0587 IMMUNOMODULATORY COMBINATION THERAPIES IN PATIENTS WITH DERMATOMYOSITIS /POLYMYOSITIS: A RETROSPECTIVE CROSS-SECTIONAL STUDY

Background: Dermatomyositis (DM)/Polymyositis(PM) is an autoimmune disease that typically involve the striated muscle with a variable involvement of the skin and other organs 1. Lymphocyte subsets disorders may contribute to the pathogenesis of DM/PM. It has been discovered that immunomodulatory drugs such as low-dose interleukin (IL)−2, rapamycin can help to regulate the lymphocyte subsets and control the disease and improve the prognosis 2-4. Objectives: To investigate the levels of peripheral lymphocyte and CD4+T subsets of DM/PM patients and further to observe the regulatory effect of modulatory therapy on these cells in PM/DM at a relative large-sample size. Methods: Total 450 patients with PM/DM and 206 healthy controls (HCs) were enrolled in this study. Among these participations, 320 patients received immunomodulatory combination therapies (immunomodulatory drugs include low-dose interleukin-2, rapamycin, metformin, retinoic acid etc). The absolute numbers of T, B, NK, CD4+T, CD8+T, Th1, Th2, Th17 and Tregs in peripheral blood of these individuals were detected by flow cytometry combined with standard absolute counting beads before and after the treatment. Results: Patients with DM/PM had lower levels of total T, CD4+T, CD8+T, Th2, Th17, NK, Th1 and Tregs compared with those of HCs (P Conclusion: The unbalance of lymphocyte cells should contribute to the pathogenesis of DM/PM patients. Immunomodulatory combination therapies could promote the proliferation and functional recovery of Tregs in patients and might help to alleviate disease activity. References: [1]Herbelet S, De Bleecker JL. Immune checkpoint failures in inflammatory myopathies: An overview. Autoimmunity reviews 2018;17(8):746-54. doi: 10.1016/j.autrev.2018.01.026 [published Online First: 2018/06/10] [2]Feng M, Guo H, Zhang C, et al. Absolute reduction of regulatory T cells and regulatory effect of short-term and low-dose IL-2 in polymyositis or dermatomyositis. International immunopharmacology 2019;77:105912. doi: 10.1016/j.intimp.2019.105912 [published Online First: 2019/11/02] [3]Zhang SX, Wang J, Sun HH, et al. Circulating regulatory T cells were absolutely decreased in dermatomyositis/polymyositis patients and restored by low-dose IL-2. Annals of the rheumatic diseases 2019 doi: 10.1136/annrheumdis-2019-216246 [published Online First: 2019/10/16] [4]Zhao C, Chu Y, Liang Z, et al. Low dose of IL-2 combined with rapamycin restores and maintains the long-term balance of Th17/Treg cells in refractory SLE patients. BMC immunology 2019;20(1):32. doi: 10.1186/s12865-019-0305-0 [published Online First: 2019/09/06] Acknowledgments: None Disclosure of Interests: None declared