Objective To analyze the levels of Th17,CD4+ CDhigh25and the related cytokines (IL-17,IL-21,TGF-β,IL-10)in the plasma of patients with SLE.Methods The percentage of Th17 and CD4+ CDhigh25 Treg cells in peripheral blood were examined by flow cytometry.QRTPCR was used to detect the mRNA expression level of RORγt and Foxp3 of 56 SLE patients (26 patients are inactive and 30 patients are active) and 28 healthy controls.Plasma cytokines levels were measured by ELISA.Results The percentage of Th17 cells in patients with SLE was higher than that of healthy controls [ (3.44 ± 0.96) % vs (2.42 ± 0.52) %,t =5.38,P =0.000 ].The percentage of CD4+ CDhigh25 Treg cells in patients with SLE was lower than that of healthy controls [ ( 1.32 ± 0.57 ) % vs ( 2.07 ± 0.67 ) %,t =3.28,P =0.034].The expressions of RORγt mRNA was increased compared with healthy controls[ (0.219 ±0.063) vs (0.087 ± 0.045 ),t =6.41,P =0.000 ],but the expressions of Foxp3 mRNA was decreased compared with healthy controls [ (0.063 ±0.045) vs (0.128 ±0.056),t =5.28,P =0.000].Plasma levelsof IL-17,IL-21 and IL-10 in SLE patients were 122.4 ( 60.5 - 188.3 ),167.2 ( 128.7 - 871.4 ),51.3(20.9 - 123.7 ) ng/L,respectively,and in the control group were 27.1 ( 18.1 - 86.2 ),31.0 ( 31.0 -424.5),33.5( 16.4 - 54.1 ) ng/L,respectively,they were significantly different between the two groups (Z =3.83,4.54,1.87,all P < 0.05 ).However,TGF-β levels were markedly decreased in SLE patients compared with controls [ 31.0 ( 31.0 - 168.6 ) ng/L vs 159.8 ( 63.4 - 389.7 ) ng/L,Z =4.87,P <0.05.IL-17 was positive correlation with Th17 cells,SLEDAI score,dsDNA antibody titers ( r =0.621,0.581,0.512,respectively,all P < 0.05 ),but was negative correlation with C3 ( r =- 0.543,P < 0.05 ) in SLE patients.Although the percentage of CD4 + CDhigh25 Treg cells were negatively correlated with SLEDAI score ( r =- 0.423,P < 0.05 ),it was positively correlated with C3 ( r =0.511,P < 0.05 ).Conclusion This study suggests that the imbalance of Th17 cells and CD4+ CDhigh25 Treg cells and the disorder of related cytokines are important in the pathogenesis of SLE patients. Key words: Lupus erythematosus,systemic; T-Lymphocytes; Cytokines