A comparison of nontreponemal tests in cerebrospinal fluid for neurosyphilis diagnosis: equivalent detection of specific antibodies

Evaluation of between-assay consistency among laboratory testing methods for neurosyphilis: a systematic review

We conducted a systematic review to analyse the consistency of nontreponemal-specific tests of Treponema pallidum in cerebrospinal fluid. We searched the PubMed, EMBASE, Web of Science, CNKI, Wanfang and Chongqing VIP databases. The inclusion criteria were studies conducted on nontreponemal-specific tests in cerebrospinal fluid (CSF) within the same population. Exclusion criteria were studies with incomplete data or where we were unable to obtain the full text, duplicate reports, case reports and studies without sensitivity or specificity results. We used kappa value analysis and McNemar's test to analyse study consistency. We initially collected a total of 198 articles and ultimately included six articles that involved 429 patients with neurosyphilis. The performance between venereal disease research laboratory tests (VDRL) and the reactive plasma regain or toluidine red serum unheated test was similar. The kappa value for consistency between VDRL and reactive plasma regain was >0.8 in three articles, and was 0.892 for consistency between VDRL and toluidine red serum unheated test in one article. Our results suggested that CSF-reactive plasma regain or CSF-toluidine red serum unheated test may serve as alternative tests in the diagnosis of neurosyphilis with CSF-VDRL.

Congenital syphilis in the twenty-first century: an area-based study

The resurgence of syphilis and subsequent risk for newborns has been described worldwide; however, European data on this congenital infection is lacking. We report the activity of a multidisciplinary specialized unit assisting a large area in the Southern Italy. A retrospective cohort study has been conducted at the Perinatal and Pediatric Infectious Diseases Units of the Federico II University of Naples, enrolling all newborns and children referred from January 2010 to June 2022 exposed to Treponema pallidum in utero and/or congenitally infected. A total of 323 patients were included in the analysis. Twenty (6.2%) received a diagnosis of confirmed congenital syphilis (CS) and one died. Fifteen CS cases had typical clinical features. Since 2017, the number of referred neonates tripled while the rate of late maternal diagnoses did not significantly differ. When compared with mothers of exposed infants, mothers of CS cases were younger (25 ± 7.2 vs 29.9 ± 6 years, p = 0.041), had less previous pregnancies (0.64 vs 1.11, p = 0.044), and received a diagnosis of syphilis at a later stage of pregnancy (86% vs 20%, from third trimester or later on; p < 0.001). Appropriate maternal therapy was protective against vertical transmission (- 1.2; - 1.4, - 1 95% CI; p < 0.001). Paternal syphilis status was known in 36% of cases.

CONCLUSION

CS has still a significant impact. Prevention should be implemented towards specific maternal risk profiles. A specialized unit is the preferable model to improve surveillance and healthcare for this neglected population.

WHAT IS KNOWN

• The resurgence of syphilis and subsequent risk for newborns has been described worldwide. • European data on this congenital infection is lacking.

WHAT IS NEW

• Congenital syphilis has a significant impact still in Europe and prevention should be implemented towards specific maternal risk profiles.  • A specialized unit is the preferable model to improve surveillance and healthcare for this neglected population.

Diagnostic tools for neurosyphilis: a systematic review

Purpose

Increasing incidences of syphilis highlight the preoccupation with the occurrence of neurosyphilis. This study aimed to understand the current diagnostic tools and their performance to detect neurosyphilis, including new technologies and the variety of existing methods.

Methods

We searched databases to select articles that reported neurosyphilis diagnostic methods and assessed their accuracy, presenting sensitivity and specificity values. Information was synthesized in tables. The risk of bias was examined using the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy recommendations.

Results

Fourteen studies were included. The main finding was a remarkable diversity of tests, which had varied purposes, techniques, and evaluation methodologies. There was no uniform criterion or gold standard to define neurosyphilis. The current basis for its diagnosis is clinical suspicion and cerebrospinal fluid analysis. There are new promising tests such as PCR tests and chemokine measurement assays.

Conclusions

The diagnosis of neurosyphilis is still a challenge, despite the variety of existing and developing tests. We believe that the multiplicity of reference standards adopted as criteria for diagnosis reveals the imprecision of the current definitions of neurosyphilis. An important next step for the scientific community is to create a universally accepted diagnostic definition for this disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06264-8.

Diagnostic role of CXCL13 and CSF serology in patients with neurosyphilis

BACKGROUND

Considering the unknown prevalence of neurosyphilis in West China, and the confusing diagnosis of neurosyphilis, the role of CSF_CXCL13 and syphilis serology was studied to provide a more accurate reference for the clinical detection and diagnosis of neurosyphilis.

METHODS

A retrospective data set I was used to investigate the prevalence of neurosyphilis, as well as the laboratory characteristics of 244 patients. Besides, to explore the diagnostic value of CSF_CXCL13 and syphilis serology for neurosyphilis, another 116 CSF_serum paired samples (data set II) were collected from 44 neurosyphilis and 72 non-neurosyphilis/syphilis patients.

RESULTS

About 6.25% (156 out of 2494) syphilis was neurosyphilis. When Treponema pallidum infection occurs, syphilis serology (sero_TRUST ≥1:16 and sero_TPPA titre ≥1:10240) can be good predictors of neurosyphilis, as well as syphilis CSF serology (CSF_TPPA ≥1:320, CSF_TRUST and venereal disease research laboratory). The sensitivity of serology in neurosyphilis can be complemented by CSF_CXCL13, which could be the therapy monitor of neurosyphilis.

CONCLUSION

Due to the lack of ideal biomarkers for neurosyphilis, the importance of syphilis serology cannot be ignored, and their combination with CSF_CXCL13 or other biomarkers should be further investigated.