Expression of IL-17 and IFN-γ in peripheral blood of patients with systemic lupus erythematosus and inhibition of dexamethasone on the secretion of cytokines

Objective To determine the levels of interleukin (IL)-17 and interferon (IFN)-γ in the plasma and in the peripheral blood mononuclear cell (PBMCS) of patients with systemic lupus erythematosus (SLE) and to investigate the effect of dexamethasone(DEX) on the secretion of IL-17 and IFN-γin PBMCs.Methods Concentrations of IL-17 and IFN-γ in plasma and in the supernatants of PBMCs which were cultured for 24 hours were measured by enzyme linked immunosorbent assay (ELISA). Results The plasma concentrations of IL-17 and IFN-γwere elevated in SLE patients as compared to the normal controls(t =4. 96,p ＜0. 001;t=2.43,p＜0.05;t=4.52,p＜0.005).The levels of plasma IL-17 showed a positive correlation with SLEDAI and the titers of anti-dsDNA antibody on the contrary(r = 0. 681,0. 492), the levels of plasma IL-17 showed a negative correlation with the levels of complement C3/C4 (r = - 0. 529, - 0. 534). No significant differences were observed between patients and controls for the spontaneous production of IL-17 and IFN-γby PBMC. Compared with normal controls after the stimulation of PMA,the level of IL-17 was significantly elevated in the supernatants of PBMCs(t = 2. 48, P ＜ 0. 05). DEX could significantly decrease the production of IL-17 and IFN-γ by PBMC (t = 3.72,3.34, P ＜0. 01). DEX showed more powerful potential of inhibiting the secretion of IL-17 by PBMC. Conclusion The expression of cytokines is obviously abnormal in SLE patients. Plasma IL-17 in SLE patients are significantly elevated and DEX can inhibit the production of IL-17. The close relationship between IL-17 and disease activity suggests that IL-17 may be a new potential target in the treatment of SLE. Key words: Lupus erythematosus, systemic;  Interleukin-17;  interferon-γ;  Dexamethasone