Caracterização e correlação do fenômeno pró-zona com títulos de sororeatividade do VDRL e reação de imunofluorescência indireta em soros de pacientes com sífilis

Abstract

Introduction: Treponema pallidum is the aetiological agent of syphilis, a sexually transmitted disease and the serology is essential for screening and diagnosis. In the immunediagnosis of this disease, two different sorts of serological tests are used. First the sera are screened in a quantitative and qualitative manner by a nontreponemal test such as the veneral disease research laboratory test (VDRL), then the reactive sera are tested for specific treponemal antibodies using the fluorescent treponemal antidody absorption assay (FTA-ABS). Objecitves and Methodology: To evaluate, using quantitative and qualitative VDRL, the sera reactivity of 40 patients bearing syphilis and compare these results to presence of prozone phenomenon and FTA-ABS. Results and discussion: The levels of sera reactivity in the VDRL test ranged from 1:2 to 1:256. The prozone phenomenon was observed in 8/40 amples (20%) and was correlated with high levels of VDRL in most of the cases. The FTA-ABS test was reactive in 39/40 cases (97,5%) with strong and moderate fluorescence intensity in most of the samples and it was independent of the VDRL reactivity levels and the presence or absence of prozone phenomenon in mos of the cases, demonstrating a higher sensibility of this method when compared to the VDRL test. Conclusion: Our results showed the importance of qualitative and quantitative VDRL assay in the serological investigation of syphilis.