Two Cases of Syphilis Patients with TPLA-positive/RPR-negative Sera

Abstract

We report herein two cases of male primary syphilis with penile ulcers. The TPLA test (Mediace Treponema Pallidum Latex Agglutination; Sekisui Chemical Co.) was positive, but the RPR test (Mediace Rapid Plasma Reagin; Sekisui Chemical Co.) was negative. TP-IgM and TP-IgG antibodies were detected in both cases by the Western blotting. The RPR results were probably negative because the patients had been treated at an early stage. TPLA, which uses latex agglutination, is thought to be able to yield positive results earlier than RPR because of the shortened of the window period.