Investigation On Syphilis Serological Tests

Background Currently,there is still no sensitive serological test available for syphilis diagnosis and treatment evaluation.Objective Establishing a syphilis antibody test based on chemiluminescence method to replace imported reagents;And to investigate certain important issues in syphilis serological tests.Contents Four different kinds of protein target antigens were employed to design treponemal antibody detection method based on chemiluminescence;Cross-sectional studies,animal experiments and case reports were conducted to investigate certain important issues in nontreponemal tests.Results(1)The sensitivity and specificity of syphilis treponemal antibody test based on chemiluminescence were 99.13%and 99.62%,respectively,and its consistency with Treponema Pallidum Particle Assay(TPPA)was 99.56%.(2)The study proposed the third algorithm of syphilis testing with a sensitivity of 99.38%and a specificity of 100%,which has a comparable diagnostic performance when comparing with reverse algorithm,and it is not need nontreponemal test in its procedure.(3)The study found that the incidence of prozone phenomenon in rapid plasma reagin(RPR)does not associate with the increase of antibody titer,however,it is more likely to be associated with disease status,pregnancy and neurosyphilis other factors.(4)The study observed that the biological false-positive reaction in RPR can be found in patients fell into 17 categories on the spectrum of disease according to the International Classification of Diseases-10,and female individuals have a 3.824-fold risk of false positive result in RPR when comparing with male individuals.(5)The animal experiments revealed that infected rabbits which subjected to treatment has identical four-fold RPR decline with untreated rabbits,and no-treatment rabbits which demonstrated four-fold RPR decline were still contagious.(6)We managed to isolate a 14d/f subtype treponema pallidum strain from CSF collected from a syphilis case with RPR/Tp-IgM negative results.Conclusion(1)The newly established treponemal antibody test based on chemiluminescence has a comparable diagnostic performance when comparing with TPPA.(2)The proposed third algorithm further simplifies the whole procedure.(3)The prozone phenomenon often occurs in patients with low and moderate titer,and also associated with pregnancy and neurosyphilis.These findings provide novel insight in the underlying mechanism of prozone phenomenon.(4)The study identified several diseases that were not previously reported to be associated with the biological false-positive reaction in RPR.(5)Animal experiments revealed that the RPR titer change is not correlated with treatment.(6)Negative results in RPR and Tp-IgM cannot rule out the activity of syphilis.