Value of an Intrathecal Synthesis Index of Specific Antitreponema IgG for Neurosyphilis Diagnosis

Retro-prospective Multicentric Study Aiming to Evaluate the Benefit of Measuring an Intrathecal Synthesis Index of Specific Antitreponema IgG for Patients Suspected of Neurosyphilis

A retro-prospective case-control Swiss study was conducted to evaluate the diagnostic performance of measuring an antibody index (AI) for intrathecal synthesis of specific anti-Treponema pallidum (T. pallidum) IgG for the diagnosis of neurosyphilis.

Study Overview

• Status: Completed
• Conditions: Neurosyphilis
• Intervention / Treatment: Diagnostic test: Measure of an antibody index for intrathecal synthesis of specific anti-Treponema pallidum IgG by ELISA.

Detailed Description

The diagnosis of neurosyphilis (NS) lacks a true "gold standard" which makes the diagnosis challenging while consequences of a misdiagnosis are potentially severe. The aim of this study was to evaluate the diagnostic performance of measuring an antibody index (AI) for intrathecal synthesis of specific anti-Treponema pallidum (T. pallidum) IgG for the diagnosis of NS.

CSF parameters were analysed and specific anti-T. pallidum IgG were measured simultaneously on paired cerebrospinal fluid (CSF)-serum samples collected between 2007 and 2022 from patients suspected of NS, in Switzerland. An AI was calculated to consider blood-brain barrier integrity. Two NS definitions were used: NS1 included patients with suspicion of NS presenting neurological symptoms and/or acute neuro-sensory signs and positive TPHA/TPPA serology and CSF-TPHA/TPPA≥320, and either CSF-leucocytes >5cells/mm3 and/or CSF-protein >0,45g/l and/or a reactive CSF-VDRL/RPR test. NS2 included patients with NS suspicion presenting acute ocular and/or otologic symptoms, and positive TPHA/TPPA serology, and a favourable response to NS treatment. Controls were patients diagnosed with any other CNS pathologies and with positive TPHA/TPPA serology.

• Study Type: Observational
• Enrollment (Actual): 181

Contacts and Locations

Study Locations

• Switzerland
  • Geneva, Switzerland, 1204
    • Laurence Toutous Trellu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

This is a bidirectional retrospective and prospective multicenter study, including all the patients presenting neurological and neuro-sensory signs (ophthalmic and auditory), for whom we have serum and cerebrospinal fluid samples, from the University Hospitals of Geneva, Zurich and Lausanne, at the ADMED Microbiology Laboratory of La Chaux-de-Fonds and in SHCS centers.

Description

Inclusion Criteria:

• All patients who have serum / CSF sample pairs collected concomitantly (3 days maximum interval between blood test and lumbar puncture).
• Age > or = 18 years old.

Exclusion Criteria:

• All patients for whom the stored samples do not meet the needs of the diagnostic study, or whose serum and CSF collection date is more than 3 consecutive days.
• Age < 18 years old.
• No written consent form for the prospective part.

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Control patients; Controls were patients diagnosed with TPHA/TPPA serology ≥80 and neurological symptoms requiring a lumbar puncture.	Diagnostic test: Measure of an antibody index for intrathecal synthesis of specific anti-Treponema pallidum IgG by ELISA.; Paired CSF/serum samples from all patients were blind tested for anti-T. pallidum IgG with an ELISA containing recombinant T. pallidum proteins (Euroimmun). The AI was calculated conforming to Reiber's method (PMID 11239944) and as previously described in Alberto et al. (PMID 35138118).
NS1 patients; NS1 includes: 1) neurological symptoms suggestive of central nervous system (CNS) involvement or acute ophthalmological or acute auditory signs consistent with neurosyhilis (NS), or syphilis with treatment serological failure (< fourfold decrease in the antibody titer of RPR/VDRL 12 months after treatment), and 2) a TPHA/TPPA serology ≥ 80 and a CSF-TPHA/TPPA test ≥ 320, and 3) either CSF-WBC > 5 cells/mm3, and/or CSF-protein > 0,45g/l in the absence of other known causes of these abnormalities, and/or a reactive CSF-VDRL/RPR test, and 4) no differential diagnosis.	Diagnostic test: Measure of an antibody index for intrathecal synthesis of specific anti-Treponema pallidum IgG by ELISA.; Paired CSF/serum samples from all patients were blind tested for anti-T. pallidum IgG with an ELISA containing recombinant T. pallidum proteins (Euroimmun). The AI was calculated conforming to Reiber's method (PMID 11239944) and as previously described in Alberto et al. (PMID 35138118).
NS2 patients; NS2 includes:1) acute ocular symptoms (recent and sudden decrease in visual acuity) and/or acute otologic dysfunctions (sudden hearing loss, acute tinnitus or vertigo) without other known diagnosis for these clinical abnormalities, 2) and a TPHA/TPPA serology ≥ 80, 3) and a response to NS treatment assessed by ophthalmologic or hearing tests and at least a fourfold reduction of RPR/VDRL titer in blood after 12 months following treatment.	Diagnostic test: Measure of an antibody index for intrathecal synthesis of specific anti-Treponema pallidum IgG by ELISA.; Paired CSF/serum samples from all patients were blind tested for anti-T. pallidum IgG with an ELISA containing recombinant T. pallidum proteins (Euroimmun). The AI was calculated conforming to Reiber's method (PMID 11239944) and as previously described in Alberto et al. (PMID 35138118).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluation of the diagnostic performance of measuring an antibody index (AI) for intrathecal synthesis of specific anti-Treponema pallidum IgG for the diagnosis of neurosyphilis.	AI testing measured with an Elisa specific for anti-Treponema pallidum IgG for all patients : number of patients with positive AI, sensitivity/specificity of the test, and positive/negative predictive values of AI test were estimated.	2020-2022 with retrospective samples from 2007 to 2019 and prospective samples from 2019 to 2022.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intrathecal oligoclonal IgG production analysis	IgG oligoclonal bands were analysed in CSF and serum of NS and control patients by the gold standard isoelectric focusing method	2020-2022 with retrospective samples from 2007 to 2019 and prospective samples from 2019 to 2022.

Collaborators and Investigators

• Sponsor: University Hospital, Geneva
• Collaborators: Swiss National Science Foundation; Swiss HIV Cohort Study

Publications and helpful links

General Publications

• Reiber H, Peter JB. Cerebrospinal fluid analysis: disease-related data patterns and evaluation programs. J Neurol Sci. 2001 Mar 1;184(2):101-22. doi: 10.1016/s0022-510x(00)00501-3.
• Alberto C, Deffert C, Lambeng N, Breville G, Gayet-Ageron A, Lalive P, Toutous Trellu L, Fontao L. Intrathecal Synthesis Index of Specific Anti-Treponema IgG: a New Tool for the Diagnosis of Neurosyphilis. Microbiol Spectr. 2022 Feb 23;10(1):e0147721. doi: 10.1128/spectrum.01477-21. Epub 2022 Feb 9.

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2019
• Primary Completion (Actual): December 31, 2022
• Study Completion (Actual): December 31, 2022

Study Registration Dates

• First Submitted: October 12, 2023
• First Submitted That Met QC Criteria: November 21, 2023
• First Posted (Actual): November 30, 2023

Study Record Updates

• Last Update Posted (Actual): November 30, 2023
• Last Update Submitted That Met QC Criteria: November 21, 2023
• Last Verified: November 1, 2023

More Information

Terms related to this study

• Keywords: Treponema pallidum; Neurosyphilis; Intrathecal synthesis; Specific anti-Treponema IgG; Otosyphilis; Ocular syphilis
• Additional Relevant MeSH Terms: Central Nervous System Diseases; Nervous System Diseases; Infections; Central Nervous System Infections; Gram-Negative Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Central Nervous System Bacterial Infections; Spirochaetales Infections; Treponemal Infections; Syphilis; Neurosyphilis; Physiological Effects of Drugs; Immunologic Factors; Antibodies
• Other Study ID Numbers: Study 2019-00232

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No