Relationship Of IL-17 And Th17 Cells To Systemic Lupus Erythematosus And Effect Of Dexamethasone On PBMCs Secretion Of IL-17 And Expression Of Th17 Cells

Relationship of Th17 cells and IL-17 to systemic lupus erythematosus and effect of dexamethasone on PBMCs secretion of IL-17 and expression of Th17 cellsPart 1 The levels and significance of plasma IL-17 and IFN-γin patients with systemic lupus erythematosusObjective To study the levels and clinical significance of plasma IL-17 and IFN-γin patients with systemic lupus erythematosus.Methods Twenty-five Chinese SLE patients(2 males and 23 females) were recruited and twenty-two healthy volunteers were recruited as normal controls. The patients were divided into two groups according to the SLE disease activity index (SLEDAI) score. Concentrations of IL-17 and IFN-γin plasma were measured by enzyme linked immunosorbent assay (ELISA), and the clinical and laboratory data of the patients were collected. The correlation between levels of IL-17 and IFN-γin plasma with anti-dsDNA antibody,SLEDAI, serum levels of C3/C4 were analyzed.Results Both of the detected cytokines(IL-17 and IFN-γ)were elevated compared to those in healthy control (P<0.05). Compared with patients with inactive SLE and normal controls,the levels of plasma IL-17 in patients with active SLE were significantly increased (P<0.005, P<0.001), and there showed no statistic differences between patients with active SLE and inactive SLE for the levels of plasma IFN-y. The levels of plasma IL-17 were positively correlated with SLE disease activity index (SLEDAI) scores. No significant correlation were observed between plasma IFN-γand SLEDAI. The levels of plasma IL-17 showed a positive correlation with the titers of anti-dsDNA antibody and serum levels of C3/C4.Conclusions The levels of plasma IL-17 are significantly elevated in SLE patients and the levels of plasma IL-17 are positively correlated with SLEDAI scores. The levels of plasma IL-17 has a strong correlation with immunology index such as high levels of anti-dsDNA antibody and low levels of serum C3/C4. IL-17 might be a novel guideline to reflect the disease activity of SLE.Part 2 Expression of Th17 cells and other T cells in peripheral blood PBMCs from the patients with systemic lupus erythematosusObjective To assess the peripheral expression of Thl7 cells in SLE patients, and to further explore the relationship between Th17 cells and other T cells, as well as the correlation in the pathogenesis of SLE.Methods Patients were grouped as described above. PBMCs were separated from SLE patients and normal controls and then was activated in vitro by PMA/Ionomycin or medium in six hours. Four-color immunofluorescent staining and flow cytometric assay were used to analyze the percentage of Th17 cells (CD3+CD8-IL-17+),Tc17 cells (CD3+CD8+IL-17+),Th1 cells (CD3+CD8-IFN-γ+),Tc1 cells (CD3+CD8+IFN-γ+),double-positive cells CD3+CD8-IL-17+IFN-γ+,CD3+CD8+IL-17+IFN-γ+ and evaluated their clinical relevance.Results The results showed that the percentages of both Tel and CD3+CD8-IL-17+IFN-γ+ in SLE patients increased significantly compared with the normal controls (P<0.001 for CD3+CD8-IL-17+IFN-γ+,P<0.005 for Tel). More importantly, the percentage of Th17 in patients with SLE was higher than that of normal controls(P<0.001).Also,the percentage of Th17 positively correlated with Thl (r=0.527,P=0.007), while there was no significant correlation between Th17 and Tc1(r=0.09, p=0.71). The percentage of Th17 cells in PBMCs positively correlated with SLEDAI (r=0.426, P=0.034), but no significant correlation were observed for the percentage of Thl cells and Tc1 cells with SLEDAI (P>0.05). There were no relationships between the percentage of Th17 cells and other clinical or laboratory indexes(including anti-dsDNA antibody, complement C3/C4,proteinuria and so on).Conclusions The increased number of Th17 cells may be an important determinant in the evolution of SLE, and Thl7 cells may effect on diffenent target cells through secreting cytokines and further induce the production of other cytokines, which lead to the disorder of function of immune regulation in SLE patients and eventually cause the disease.Part 3 Effect of Dexamethasone on the expression of T cells and the secretion of cytokines in the peripheral blood mononuclear cells in patients with systemic lupus erythematosusObjective To investigate the influence of dexamethasone on the expression of T cells and the secretion of IL-17,IFN-γin the peripheral blood mononuclear cells in patients with systemic lupus erythematosus and to provide a new theoretical and laboratory basis for the clinical application of corticosteroids.Methods Patients were grouped as described above. PBMCs were separated from SLE patients and normal controls and then was cultured in vitro by PMA/Ionomycin or PMA/Ionomycin+dexamethasone or medium for six hours or twenty-four hours. Four-color immunofluorescent staining and flow cytometric assay were used to analyze the percentage of Th17 cells (CD3+CD8-IL-17+),Tc17 cells (CD3+CD8+IL-17+),Th1 cells (CD3+CD8-IFN-γ+),Tc1 cells (CD3+CD8+IFN-γ+),double-positive cells CD3+CD8-IL-17+IFN-γ+,CD3+CD8+IL-17+IFN-γ+. Concentrations of IL-17 and IFN-γin the supernatants of PBMCs which were cultured for 24 hours were measured by enzyme linked immunosorbent assay(ELISA).Results No significant differences were observed between patients and controls for the spontaneous production of IL-17 and IFN-γby PBMCs and the percentage of Th17,Tc17,Th1,Tc1,CD3+CD8-IL-17+IFN-γ+,CD3+CD8+IL-17+IFN-γ+ cells.After the stimulation of PMA, compared with medium controls, the levels of IL-17 and IFN-γwere significantly elevated in the supernatants of PBMCs(P<0.001), likewise, the percentage of the six subsets of T cells in patients were also significantly increased (P<0.01). DEX could significantly decrease the percentages of Th17,Tc17,Th1,Tc1 cells and lower the production of IL-17 and IFN-γby PBMCs. DEX showed more powerful potential of inhibiting the secretion of IL-17 by PBMCs.Conclusions Our data support the idea that dexamethasone may induce a shift from the Thl/Th2 balance to Th2 profile of cytokines secretion. More important, DEX may inhibit the production of IL-17. Our results may offer new insight into the mechanism of efficacy of immunosuppressive therapy in SLE, and provide some laboratory proof and reference for the clinical application of corticosteroids.