OP0244 EFFICACY AND SAFETY OF LOW-DOSE IL-2 IN PATIENTS WITH MULTIPLE MYOSITIS/DERMATOMYOSITIS
Authors: He-Hua Sun, Sheng-xiao Zhang, Jia Wang, Yu-Fei Hao, Guang-Ying Liu, Caihong Wang, Chong Gao, LI Xiao-Feng
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Dermatomyositis (DM) and polymyositis (PM) are rare chronicinflammatory disorders with significant associated morbidityand mortality despite treatment <sup>[1, 2]</sup>, characterized by subacute onset of proximal muscle weakness, elevated muscle enzymes, and inflammatory infiltrates on muscle biopsy. Although several hypotheses have been proposed for triggers of inflammation in the diseases <sup>[3]</sup>, growing evidences have focused on the immune disorders <sup>[4]</sup>. However, the quantitative changes of lymphocyte subsets in DM/PM are unclear and whether low-dose IL-2 could rebalance the lymphocyte subsets and further benefit to remission disease activity of DM/PM patients is unknown. <h3>Objectives</h3> To investigate the quantitative status of peripheral blood lymphocyte subsets in the patients for the exploration of pathogenesis and evaluate the safety and efficacy of low-dose IL-2 therapy in patients with DM/PM. <h3>Methods</h3> From February 2016 to October 2018, total 147 patients with PM/DM and 128 gender and age matched healthy individuals were enrolled in this study. The absolute numbers of T, B, NK, CD4+T, CD8+T, Th1, Th2, Th17 and Treg cells in peripheral blood of these individuals were detected by flow cytometry combined with standard absolute counting beads. Patients in IL-2 group (n=31) were not only given traditional treatments, but injected subcutaneously human IL-2 (aldesleukin) at 50 WIU per day for a 5-day course. The demographic features, clinical manifestations and laboratory indicators were compared before and after the treatment. <h3>Results</h3> Patients with PM/DM had lower levels of Treg cells as well as T, CD4+T, CD8+T, Th1, Th2, and Th17 compared with those of the healthy controls (P &lt; 0.05), which was correlated with disease activity(P &lt; 0.05). After IL-2 administration, the absolute numbers of peripheral lymphocyte subsets in patients were significantly increased (P &lt; 0.05), leading to a better remission compared with the patients received conventional therapy (P &lt; 0.05). <h3>Conclusion</h3> The difference status of peripheral lymphocyte subsets, especially Tregs, between PM/DM patients and healthy individuals suggests that lymphocyte subsets may be involved in and play an important role in the pathogenesis of patients. Low-dose IL-2 can effectively increase the level of Treg cells as well as other lymphocytes to some degree and maintain the immunologic balance, which may help for PM/DM patients' symptoms remission without over-treatment and evaluated side effect. But long-term benefits of IL-2 therapy are required to further study. <h3>References</h3> [1] Erin, V. and L. T. Sarah, et al. (2015). "The evidence for immunotherapy in dermatomyositis and polymyositis: a systematic review." Clin Rheumatol 34 (12): 2089-95. [2] Thomas, B. and F. Romain, et al. (2018). "Treatment of idiopathic inflammatory myositis associated interstitial lung disease: A systematic review and meta-analysis." Autoimmun Rev. [3] Angela, C. and D. S. Maria, et al. (2017). "The Immune Response and the Pathogenesis of Idiopathic Inflammatory Myositis: a Critical Review." Clin Rev Allergy Immunol 52 (1): 58-70. [4] V, P. and C. E (2018). "Dermatomyositis: a slow path towards targeted therapies or will conventional therapies prevail?" Br J Dermatol 179 (6): 1233-1234. <h3>Acknowledgement</h3> No. <h3>Disclosure of Interests</h3> None declared