Abstract: Objective: To investigate the relationship between Th1，Th2，Treg and Th17 related cytokines and serofast syphilitic. Methods: The levels of Th1，Th2，Treg and Th17-related cytokines (IFN-γ, IL-2, IL-12, IL-4, IL-10, IL-6, IL-17, IL-22, TGF-β) in peripheral blood of different groups (serofast syphilis, syphilis, syphilis seroconvert and control) were detected by ElISA. Results: The levels of IFN-γ , IL-2 and IL-12 were lower and the levels of IL-4, IL-10 and TGF-β were higher in the Syphilis serofast group than in the syphilis group, syphilis seroconvert group and control group, with significant differences (Ps<0.05). The level of IL-17 in serofast syphilis group was significantly lower than that in syphilis group and control group (Ps<0.05), while IL-22 in serofast syphilis group was significantly lower than that in syphilis group (P<0.05), IL-6 in syphilis serofast group was significantly higher than that in control group (P<0.05). Conclusion: The imbalance of Th1，Th2，Treg and Th17 cells and TH17 cells may exist in the patients with serofast syphilis, which affects the whole immune response level of the patients.

Key words: syphilis serofast, Th1 cells, Th2 cells, Treg cells, Th17 cells, cytokines