Evaluation of an Enzyme Immunoassay Technique for Detection of Antibodies against Treponema pallidum

Abstract

In the present study, the performance of an enzyme-linked immunosorbent assay (ELISA) technique (Eti-syphilis-G and Eti-syphilis-M; DiaSorin) for detection of Treponema pallidum immunoglobulin M (IgM) and IgG antibodies for the laboratory diagnosis of syphilis was evaluated. Four hundred forty-one samples were studied. The sensitivity and specificity of the ELISA were 100 and 93%, respectively, compared with the results of a microhemagglutination assay for Treponema pallidum (MHA-TP) and 99.4 and 100%, respectively, compared with the results of the fluorescent treponemal antibody absorption (FTA-Abs) test. The results of the ELISA technique were concordant with those of MHA-TP for 98% of the samples tested, while the rate of concordance with the FTA-Abs test was 99.5%. The sensitivities of the rapid plasma reagin (RPR) test, MHA-TP, and the ELISA in the different phases of syphilis compared with the results of the FTA-Abs test were 92, 88, and 100%, respectively, for patients with primary syphilis; 100% for all tests evaluated for patients with secondary syphilis; 97.2, 99.4, and 100%, respectively, for patients with latent syphilis; and 57.9, 92.6, and 97.9%, respectively, for patients with past treated syphilis. The RPR test was reactive with 12 samples that were negative by all the specific tests. IgM antibodies were most frequently detected by the ELISA for IgM antibodies (32.8%) than by the FTA-Abs for IgM antibodies (28.4%). Detection of these antibodies by the FTA-Abs test and the ELISA for IgM antibodies decreased with the stage of disease (72 and 88%, respectively, for patients with primary syphilis to 17 and 19%, respectively, for patients with early latent syphilis). The high sensitivity and specificity of this ELISA technique during all stages of syphilis, together with the fact that it is a simple, objective, and easily automated method, lead us to believe that it could be used as a screening test for syphilis.

Laboratory diagnosis of syphilis with automated immunoassays

“…Several different immunoassays set up with whole-cell lysate (12)(13)(14)(15) or recombinant T. pallidum antigens (16)(17)(18)(19)(20)(21)(22) are described in the literature.…”

“…Nontreponemal tests include the Venereal Disease Research Laboratory and the Rapid Plasma Reagin (RPR) card tests. Treponemal tests include the serum fluorescent treponemal antibody absorption test, the T. pallidum hemagglutination test (TPHA) (Radim, Pomezia, Italy), the enzyme-linked immunoassay (ELISA), and the Western Blot (WB) assay; both ELISA and WB tests can be based on either whole-cell lysate (12)(13)(14)(15) or recombinant (16)(17)(18)(19)(20) treponemal antigens. More recently, chemiluminescent immunoassays set up with recombinant antigens have been evaluated (21,22).…”

Profile of Anti-Tp47 antibodies in patients with positive serology for syphilis analized by western blot

“…Formerly, several ELISA based on whole cell lysate were developed and they presented sensibility of 93.3% to 100% and specificity of 95.5% to 99.8% [4][5][6][7]. In recent years, as well as in other diseases, the trend is to use the recombinant antigens, mainly the fractions of 47kDa, 17KDa and 15kDa.…”

The role of Point-of-Care testing in the diagnosis of syphilis

“…When there is no laboratory testing available, the treatment of symptomatic syphilis (primary, secondary, and tertiary) can still be performed by taking into account the signs and symptoms of the different stages of the disease. However, diagnostic problems arise in asymptomatic or treated patients, who, in our experience, are the majority of cases [12][13][14][15].…”