AB1321 The expansion of myeloid-derived suppressor cells in patients with rheumatic diseases
Authors: J. Zhu, S. Chen, L. Wu, R. Wang, D. Zhao, J. Li
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells with a remarkable ability to suppress the immune system. Although MDSCs were found to suppress the T cell response of some cancer patients and tumour bearing mice, the role of those cells have been revealed in patients with RA, SLE, and IBD. Nevertheless, most rheumatic diseases have a common pathological process, such as inflammatory arthritis and systemic tissue damage. Whether or not MDSCs and their subsets are abnormally expressed in patients with inflammatory-associated rheumatic diseases is still unclear. <h3>Objectives</h3> To investigate the proportion of MDSCs and their subsets in patients with different rheumatic diseases and clarify the association between those cells and patients clinical data including the disease activity index and the inflammation of joints. <h3>Methods</h3> One hundred and nine patients with various rheumatic diseases and twenty-five healthy controls were recruited. The common clinical characteristics and the special clinical indexes for each rheumatic disease were obtained from patients. The MDSCs and their subsets were marked with fluorescently labelled antibodies and were then analysed with flow cytometry. All statistics were calculated with SPSS 20.0. A p&lt;0.05 was considered to be statistically significant. <h3>Results</h3> The patients included 31 with RA, 21 with AS, 14 with OA, 11 with SLE with arthritis, 13 with SLE without arthritis, 9 with Gout, 10 with HUA, and 25 healthy controls. The proportions of MDSCs, M-MDSCs, and G-MDSCs were higher in patients with RA than in healthy controls (6.56%±6.77% vs. 1.46±0.96%, 2.52±3.81% vs. 0.35±0.35%, 1.13±1.64% vs. 0.18±0.14%; p&lt;0.001). The same increase in the number of MDSCs and their subsets was also found in patients with AS, OA, SLE with arthritis, and Gout. The proportions of MDSCs and M-MDSCs were mostly correlated with the patient's joint inflammation indexes (such as CRP and total joint pain) and the disease activity. Additionally, an increased risk of arthritis was found from MDSCs, M-MDSCs, and G-MDSCs (OR=2.417, 13.257, 6.204; 95% CI=1.625–3.597, 3.974–44.223, 1.798–21.406; p&lt;0.01). When other cell subsets were adjusted, the same risk was also obtained for the expansion of M-MDSCs (adjusted OR=5.772; 95% CI 1.174–28.369; p=0.031). <h3>Conclusions</h3> The expansion of MDSCs and their subsets were found to be correlated with the disease activity and joint inflammation in patients with different rheumatic diseases. Further analysis revealed that the proportion of M-MDSCs was associated with the risk of arthritis in those populations. <h3>Acknowledgements</h3> Supported by the Natural Science Foundation of Guangdong Province<sup>No. 2017</sup>A030313868), and the President Foundation of Nanfang Hospital, Southern Medical University<sup>No. 2016</sup>C024). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. <h3>Disclosure of Interest</h3> None declared