METHODS: Serum samples were collected from 69 subjects (male 45, female 24) diagnosed with
syphilis and analyzed by Western blotting for the expression of
IgM and
IgG against the four
protein antigens. Expression levels of the target
antibodies were compared during the same stage of
syphilis as well as between different stages of this disease.
RESULTS: In subjects with
primary syphilis, the positive rate of Tp45
IgM was higher than that of other TP-
IgM. Tp15
IgM was detected only in subjects with
tertiary syphilis. Similarly, the seroprevalence of Tp45
IgG in
primary syphilis was higher than for other TP-
IgG. No target TP-
IgM was detected in subjects with
latent syphilis. In subjects with
secondary syphilis, the expression level of Tp15
IgG (138.73 ± 20.16) was higher than for other target TP-
IgG. In subjects with
tertiary syphilis, all target TP-
IgG were detected. In subjects with tertiary or
latent syphilis, the expression levels of Tp45
IgG (121.33 ± 11.04 and 110.10 ± 40.19, respectively) were higher than those of other target TP-
IgG. The expression levels of all Tp-
IgM were similar before or after anti-
syphilis treatment. In comparison, the expression levels of all TP-
IgG decreased compared with the pre-treatment levels, and this decrease was statistically significant (both P < 0.05) for Tp17
IgG and Tp47
IgG.
CONCLUSIONS: After Treponema pallidum
infection, Tp45
IgM appeared first and Tp15
IgM occurred during later stages. The positive rates of all TP-
IgG increased with the duration of this disease. Anti-
syphilis treatment reduced the expression levels of Tp17
IgG and Tp47
IgG. Larger-scale studies are required to further validate the value of Tp15, Tp17, Tp45, and Tp47 as markers for the early detection of primary and
latent syphilis.