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AB0073 RELATIONSHIPS BETWEEN CYTOKINE PROFILES AND TH17/TREG BALANCE IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background: Rheumatoid arthritis (RA) is an autoimmune inflammatory disease. Cytokines serve as the mediators of cellular differentiation, inflammation, immune pathology, and regulation of immune response in this disease. [1] A previous study demonstrated that the imbalance between Th17 and Treg cells is an important mechanism which may lead to RA. [2] However, the effect of cytokines on the balance of Th17/Treg cells in patients with RA remains unknown. Objectives: To investigate the relationships between various cytokine levels and Th17/Treg balance in patients with RA. Methods: The study include75 RA patients, meeting the diagnostic classification criteria for RA revised by ACR in 1987 and with DAS28 scores were greater than 2.6, and 75 health controls. The absolute numbers of lymphocyte cell subsets and T subsets in peripheral blood were measured by Flow Cytometer (FCM). Serum levels of the following 6 cytokines were determined in the same samples using a cytometric beads array: Interleukin-2(IL-2), Interleukin-4(IL-4), Interleukin-6(IL-6), Interleukin-10(IL-10), Interferon-γ(INF-γ) and Tumor necrosis factor-α(TNF-α) for all RA patients. Results: (1) Compared with healthy controls, the absolute counts of B cells (P=0.042), the absolute counts of Th1 cells (P=0.031) and the ratio of Th1/Th2 (P=0.000) are significantly increased in RA patients. In contrast, the absolute counts of NK cells (P=0.032) and the absolute count of Th2 cells (P=0.000) were significantly decreased in the RA patient. (Figure1) (2) There was no significant difference in the absolute number of Th17 cells between the two groups, but absolute counts of Treg cells are significantly decreased in RA patients, the ratio of Th17/Treg also have obvious difference, which was higher in RA patients. (Figure1) (3) Among 75 RA patients, two cytokines were significantly associated with the ratio of Th17/Treg, IL-4 (r=0.264, P=0.023) and TNF-α (r=0.270, P=0.020), while other cytokines have no correlation. (Figure2) Conclusion: Rheumatoid arthritis (RA) is a chronic disease involving various immune cells, our research show that decreased NK cells, Th2 cells and Treg cells; increased B cells, Th1 cells and the ratio of Th17/Treg may be key pathophysiological features in patients with RA. Meanwhile, the level of serum IL-4 and TNF-α may influence the ratio of Th17/Treg, that means we can maintain the patient‘s Th17/Treg immune balance by regulating the levels of such cytokines. Further researches are needed to elucidate the possible mechanisms with this phenomenon. References [1] Astry, B.; Harberts, E.; Moudgil, K.D. A cytokine-centric view of the pathogenesis and treatment of autoimmune arthritis. J. Interferon Cytokine Res. 2011, 31, 927–940. [2] Liu J, Hong X, Lin D, et al. Artesunate influences Th17/Treg lymphocyte balance by modulating Treg apoptosis and Th17 proliferation in a murine model of rheumatoid arthritis[J]. Experimental and Therapeutic Medicine, 2017.13(5):2267-2273.Figure 1 The absolute number of B cell, NK cell, Th1 cell, Th2 cell, Treg cell in RA patients and health controls, Data are expressed as means ±SD.Figure 2 Correlation of the serum levels of IL-4 and TNF- α with the ratio of Th17/Treg. Disclosure of Interests: None declared