Tim-3/Gal-9 Expression On Cell Subsets And Association With Angiogenesis And Inflammation In Rheumatoid Arthritis

ObjectiveRheumatoid arthritis (RA) is a chronic inflammatory and autoimmune disease, and which is characterized of inflammatory cytokines and immune cell infiltration and synovial angiogenesis. Angiogenesis is the formation of new capillaries from pre-existing vessels in physiological and pathological conditions. T cell immunoglobulin domain and mucin-3 (Tim-3) has been reported as an important regulatory molecule and plays a pivotal role in RA. Galectin-9 (Gal-9) is the ligand of Tim-3. Both Gal-9 and Tim-3 contribute to the pathogenesis of various autoimmune diseases, including RA.The main purpose of this study was to test the expression ratios of Tim-3 and Gal-9 on immune cells of all enrollments and their correlation with disease activity, inflammatory cytokines and angiogenesis in RA patients. Moreover, we can clarify whether Tim-3 and Gal-9 can be a biomarker of RA patients’disease activity.Methods87 patients who were diagnosed with rheumatoid arthritis were collected from Qilu Hospital of Shandong University as RA group, all enrolled met the criterion of the American College of Rheumatology (ACR) diagnostic criteria in 1987. Their clinical data were collected including gender, age, the count of white blood cells (WBC), erythrocyte sedimentation rate(ESR), C-reactive protein(CRP), the painful and swellen number of 28 joints’(T28 and SW28).63 age-and sex-matched healthy people were worked as Heathy controls (HCs group).Expression of Tim-3 and Gal-9 on different cell subsets including CD4+, CD8+, Regulatory T cells(Treg), CD4"CD8" (Double negative T cells, DNT) and monocytes (MC) in peripheral blood of all enrollments were analyzed by flow cytometry. The levels of TNF-a, IL-6, IL-17, IL-37,pVEGF, pGal-9 in plasma of RA patients and HCs were assayed using enzyme-linked immuno sorbent assay (ELISA). SPSS 20.0 software was used for data analysis.Results1. The count of WBC, Treg and MC in RA group were all higher than those in HCs group, while CD8+T and DNT were lower than HCs, which were considered statistically significant respectively (P<O.05).2. Tim-3 expression proporation on CD4+, CD8+, Treg, DNT and MC cells subsets were significantly higher in RA than in HCs(P<0.05). While the Gal-9 expression levels in these subsets were no difference between the two groups in ststistics (P>0.05).3. The plasma concentrations of pVEGF, IL-6, TNF-a and pGal-9 in RA group were significantly higher than HCs group (P<0.05).4. Tim-3 expression ratios were consistently correlated in all these diferent T subsets in peripheral of RA patients. Tim-3 expression on CD4+, CD8+, Treg subsets membrance were correlated with Gal-9 level in CD8+T cells in RA. While these Tim-3 levels were not correlated to inflammatory factors and disease activity marks of patients.5. Gal-9 levels in CD4+, CD8+, Treg, DNT and MC subsets were significantly correlated with each other. Gal-9 expression on these subtypes were positively correlated with TNF-a in plasma, VEGF and VEGFRl level in T cells, and diseases activity marks such as DAS28, CRP, SDAI, in the patients with RA.6. There were obviously positively correlation between VEGF and VEGF, VEGFRl and VEGFRl, VEGF and VEGFRl level on above-mentioned five subsets. VEGF and VEGFR1 expression ratios on T subtypes positively correlated with TNF-α level in plasma and DAS28, SDAI score.ConclusionsThe percentage of T subsets and MC in peripheral blood of RA patients differ to that of HCs group. RA group has higher Treg subsets and lower DNT subsets. The function of these two negative regulatory T subtypes looks different. Tim-3 and Gal-9 expression on different cell subsets are not the same and change inconsistently. Tim-3 level on T subsets and MC is higher in RA than HCs, while it has no correlation with disease activity of RA. On the other hand, Gal-9 expression on these subtypes have no difference between the patients and HCs groups. The expression of Gal-9 on T subsets closely correlates with VEGF and VEGFR1 levels on some subsets, TNF-α level in plasma and disease activity index such as DAS28 and SDAI. This suggests that Gal-9 plays important roles in inflammation and angiogenesis in RA. And probably, Gal-9 may worked as the biomarker of disease activity, inflammation and angiogenisis in RA patients, and it may be the potential target of RA treatment.