Characterization of the Western blotting IgG reactivity patterns in the clinical phases of acquired syphilis

We standardized the Western blotting (WB) method for detecting Treponema pallidum IgG (Tp-IgG) antibodies in sera samples of patients with syphilis and correlated the reactivity profile of bands with the clinical phases of the disease. The WB Tp-IgG has 100% sensitivity and 99.5% specificity. The clinical phases of the disease were associated with the reactive bands from TpN15 to TpN47. Quantitative Venereal Disease Research Laboratories was used to assist the WB Tp-IgG analysis. In primary syphilis, the reaction intensity for the antigenic band TpN47 was usually more intense when compared with other clinical phase. In secondary and sometimes in early latent syphilis, antibodies reacted with high numbers of antigenic proteins of T. pallidum. In late latent syphilis, various bands became negative, but the TpN15 and TpN47 were reactive. In tertiary syphilis, we observed reactivity with the TpN15 band and low reactivity with the TpN47. We concluded that WB Tp-IgG could be used to confirm serologic tests and characterize clinical phases of syphilis.