日本性感染症学会誌 Journal of Japanese Society for Sexually Transmitted Infections

We examined the transition between the pre- and post-treatment results of a syphilis antibody test in patients with primary-stage syphilis. In this study, we characterized the automated rapid plasma regain (RPR) and Treponema pallidum latex agglutination (TPLA) tests. Of the 44 patients diagnosed with primary-stage syphilis using polymerase chain reaction (PCR), only 16% were tested positive in the RPR or TPLA tests before treatment. This indicates that the initial diagnosis requires both RPR and TPLA tests. Moreover, 23% of the patients were tested negative in both RPR and TPLA tests before treatment, which supports the concomitant use of PCR whenever possible. After treatment, results from the automated RPR test rapidly decreased, which indicates their usefulness as a remission indicator, similar to the 2-fold serial dilution method. Patients with negative pre-treatment TPLA results and those with <200 T.U. exhibited post-treatment increase of results for up to 6 months. On the other hand, patients with a pre-treatment TPLA value ≥300 T.U. exhibited a decrease in results at 2 months post-treatment. Upon reinfection, TPLA results increased markedly compared with RPR results. Our findings suggest that the concomitant use of RPR and TPLA tests pre- and post-treatment contributes to determine the pathological status of syphilis patients.