['To investigate the role of Th17/Treg unbalance in the pathogenesis of experimental autoimmune encephalomyelitis (EAE).', 'EAE was modeled in mice and the number of regulatory T cells (Tregs) in spleen of EAE mice was detected by flow cytometry. The expressions of Foxp3 and RoR-γt mRNA in the spleen of EAE mice and IL-17 mRNA in the brain of EAE mice were evaluated by real-time quantitative PCR and the levels of IL-6, TGF-β and IL-17 in the serum of EAE mice were examined by ELISA.', 'Compared with control group, the number of CD4(+)CD25(+) Foxp3(+) Tregs and the expression of Foxp3 mRNA in the spleen of EAE mice dramatically decreased in the early and peak stage of EAE (P<0.05), but increased in chronic stage of EAE (P<0.05); the RoR-γt mRNA expression from mouse spleen at the early stage of EAE was significant raised (P<0.05), but was not significantly different at the peak and chronic stage of EAE from that in control group (P>0.05). The levels of IL-6 and TGF-β in the serum of EAE group dramatically increased compared with control group (P<0.05). With the development of EAE, the level of IL-6 gradually decreased, and there was no statistical difference in the chronic stage of EAE compared with control group (P>0.05). However, the level of TGF-β was higher than that in control group in the chronic stage of EAE (P<0.05). Compared with those in control group, the concentration of IL-17A and the expression of IL-17 mRNA dramatically increased in different stages of EAE group, especially in peak stage (P<0.05).'] Is [ Th17/Treg unbalance involved in the pathogenesis of experimental autoimmune encephalomyelitis ]?