Abstract: Objective　To investigate the role of interleukin-2 （IL-2），interleukin-10（IL-10） and tumor necrosis factor-alpha（TNF-α）in the pathogenesis of early symptomatic syphilis. Methods　Double-antibody sandwich enzyme-linked immunosorbent assay（DAbS-ELISA） was used to detect the serum levels of IL-2，IL-10 and TNF-α in 53 patients with early symptomatic syphilis （25 cases with primary syphilis and 28 cases with secondary syphilis） and 65 healthy subjects. Results　Serum levels of IL-2，IL-10 and TNF-α in early symptomatic syphilis group were significantly higher than those in control group （P<0.01）. Serum levels of IL-2 and TNF-α in primary syphilis group were significantly higher than those in secondary syphilis group （P<0.01）. Serum level of IL-10 in secondary syphilis group was significantly higher than that in primary syphilis group （P<0.01）. IL-2 and IL-10 were negatively correlated in early symptomatic syphilis group （r＝－0.760，P＝0.000）. IL-2 and TNF-α were positively correlated（r＝0.633，P＝0.000），and IL-10 and TNF-α were not correlated（r＝－0.063，P＝0.575）. Conclusions　IL-2， IL-10 and TNF-α are involved in the pathogenesis of syphilis. Up-expression of IL-10 may contribute to the helper T cell （Th）1/Th2 immune response imbalance during the development of early symptomatic syphilis.

Key words: Interleukin-2, Interleukin-10, Tumor necrosis factor-alpha, Syphilis