Abstract: Objective To investigate the expression of Th1/Th2 cytokines in early symptomatic syphilitic lesions and its relationship with the sero-conversion of RPR test in patients with syphilis.Methods The expression of Th1/Th2 cytokines in lesions from 30 patients with early symptomatic syphilis was immunohistochemically detected with ABC method.The serum titers of RPR test in these patients were measured in 1, 3, 6, 9 and 12 months after routine benzathine penicillin treatment.Results Among 10 cases of primary syphilis, the express ion of both Th1 and Th2 cytokines in the lesions was found in 9 cases, while only Th1 cytokine expression was observed in the remainder case; and the sero-conversion of RPR test occurred in all 10 cases during the follow-up period.Among 20 cases of secondary syphilis, Th1/Th2 cytokines expressed in the lesions in 16 c ases, and only Th2 cytokines expressed in 4 cases; and the sero-conversion of RP R test was found in 12 cases during the follow-up period.The expression of Th1 cytokines in early syphilitic lesions was positively correlated with the sero-conversion of RPR test.The higher the expression of IFN-γ, the more likely the sero-conversion of RPR test.Conclusion The early activation and persistence of the expression of Th1 cytokines may play an important role in the clearance of pathogens.

Key words: Syphilis, Interleukin-2, Interleukin-4, Interleukin-10, Interferon typeⅡ, Prognosis