Dataset Information

Cerebrospinal Fluid Treponema pallidum Particle Agglutination Assay for Neurosyphilis Diagnosis.

ABSTRACT: Limited data suggest that the cerebrospinal fluid Treponema pallidum particle agglutination assay (CSF-TPPA) is sensitive and a CSF Treponema pallidum hemagglutination assay (CSF-TPHA) titer of ?1:640 is specific for neurosyphilis diagnosis. CSF-TPPA reactivity and titer were determined for a convenience sample of 191 CSF samples from individuals enrolled in a study of CSF abnormalities in syphilis (training data set). The sensitivity of a reactive test and the specificity for reactivity at serial higher CSF dilutions were determined. Subsequently, CSF-TPPA reactivity at a 1:640 dilution was determined for all available samples from study participants enrolled after the last training sample was collected (validation data set, n = 380). Neurosyphilis was defined as (i) a reactive CSF Venereal Disease Research Laboratory test (CSF-VDRL), (ii) detection of T. pallidum in CSF by reverse transcriptase PCR, or (iii) new vision loss or hearing loss. In the training data set, the diagnostic sensitivities of a reactive CSF fluorescent treponemal antibody absorption test (CSF-FTA-ABS) and a reactive CSF-TPPA did not differ significantly (67 to 98% versus 76 to 95%). The specificity of a CSF-TPPA titer of ?1:640 was significantly higher than that of lower dilutions and was not significantly different from that of CSF-VDRL. In the validation data set, the diagnostic specificity of a CSF-TPPA titer of ?1:640 was high and did not differ significantly from that of CSF-VDRL (93 to 94% versus 90 to 91%). Ten CSF samples with a nonreactive CSF-VDRL had a CSF-TPPA titer of ?1:640. If a CSF-TPPA titer of ?1:640 was used in addition to a reactive CSF-VDRL, the number of neurosyphilis diagnoses would have increased from 47 to 57 (21.3%). A CSF-TPPA titer cutoff of ?1:640 may be useful in identifying patients with neurosyphilis when CSF-VDRL is nonreactive.

SUBMITTER: Marra CM

PROVIDER: S-EPMC5442543 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

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Cerebrospinal Fluid Treponema pallidum Particle Agglutination Assay for Neurosyphilis Diagnosis.

Marra Christina M CM Maxwell Clare L CL Dunaway Shelia B SB Sahi Sharon K SK Tantalo Lauren C LC

Journal of clinical microbiology 20170405 6

Limited data suggest that the cerebrospinal fluid <i>Treponema pallidum</i> particle agglutination assay (CSF-TPPA) is sensitive and a CSF <i>Treponema pallidum</i> hemagglutination assay (CSF-TPHA) titer of ≥1:640 is specific for neurosyphilis diagnosis. CSF-TPPA reactivity and titer were determined for a convenience sample of 191 CSF samples from individuals enrolled in a study of CSF abnormalities in syphilis (training data set). The sensitivity of a reactive test and the specificity for reac ...[more]

PMID: 28381602

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Project description:Syphilis serodiagnosis is challenging because distinct clinical forms of the infection may influence serological performance and discordant results between tests make clinical decisions difficult. Several recombinant Treponema pallidum-proteins have already been tested for syphilis diagnosis and they are critical to achieve high accuracy in serological testing. Our aim was to assess the varied from performance of T. pallidum-recombinant proteins TmpA, TpN17 and TpN47 for syphilis serodiagnosis. The proteins were evaluated using sera of 338 T. pallidum-negative, 173 T. pallidum-positive individuals and 209 sera from individuals infected with unrelated diseases. The diagnostic potential was validated by analysis of ROC curves. In the liquid microarray analyses, the ROC curve varied from 99.0% for TmpA and TpN17 to 100% for TpN47. The sensitivity score yielded values of up to 90% for TpN17, 100% for TpN47 and 80.0% for TmpA. The lowest and highest specificity values were presented by TpN47 (91.9%) and TmpA antigens (100%), respectively. TpN47 showed the highest accuracy score (95.5%) among all the recombinant proteins assayed. For the ELISA, the ROC curve was 97.2%, 91.8% and 81.6% for TpN17, TmpA and TpN47, respectively. TpN17 and TmpA yielded a sensitivity of 69.9%, while TpN47 obtained a value of 53.8%. Specificity was almost 100% for all three proteins. No cross-reaction was observed for TpN17 in the serum samples from non-bacterial infections. Regarding leptospirosis-positive samples, cross-reactivity score was varied from 8.6 to 34.6%. This is most probably due to conservation of the epitopes in these proteins across bacteria. The use of recombinant proteins in immunoassays for syphilis diagnosis was showed provide greater reliability to results of the treponemal assays. Despite the low sensitivity, the proteins showed high diagnostic capacity due to the AUC values found. However, an improvement in sensitivity could be achieved when antigenic mixtures are evaluated.

Project description:Five immunodominant Treponema pallidum recombinant polypeptides (rTpN47, rTmpA, rTpN37, rTpN17, and rTpN15) were blotted onto strips, and 450 sera (200 from blood donors, 200 from syphilis patients, and 50 potentially cross-reactive) were tested to evaluate the diagnostic performance of recombinant Western blotting (recWB) in comparison with in-house whole-cell lysate antigen-based immunoblotting (wclWB) and T. pallidum hemagglutination (MHA-TP) for the laboratory diagnosis of syphilis. None of the serum specimens from blood donors or from potential cross-reactors gave a positive result when evaluated by recWB, wclWB, or MHA-TP. The evaluation of the immunoglobulin G immune response by recWB in sera from patients with different stages of syphilis showed that rTmpA was the most frequently identified antigen (95%), whereas only 41% of the specimens were reactive to rTpN37. The remaining recombinant polypeptides were recognized as follows: rTpN47, 92.5%; rTpN17, 89.5%; and rTpN15, 67.5%. The agreement between recWB and MHA-TP was 95.0% (100% with sera from patients with latent and late disease), and the concordance between wclWB and MHA-TP was 92.0%. The overall concordance between recWB and wclWB was 97.5% (100% with sera from patients with secondary and late syphilis and 94.6 and 98.6% with sera from patients with primary and latent syphilis, respectively). The overall sensitivity of recWB was 98.8% and the specificity was 97.1% with MHA-TP as the reference method. These values for sensitivity and specificity were slightly superior to those calculated for wclWB (sensitivity, 97.1%, and specificity, 96.1%). With wclWB as the standard test, the sensitivity and specificity of recWB were 98.9 and 99.3%, respectively. These findings suggest that the five recombinant polypeptides used in this study could be used as substitutes for the whole-cell lysate T. pallidum antigens and that this newly developed recWB test is a good, easy-to-use confirmatory method for the detection of syphilis antibodies in serum.

Dataset Information

Cerebrospinal Fluid Treponema pallidum Particle Agglutination Assay for Neurosyphilis Diagnosis.

Publications

Cerebrospinal Fluid Treponema pallidum Particle Agglutination Assay for Neurosyphilis Diagnosis.

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