Cerebrospinal fluid CXCL13 concentration for diagnosis of neurosyphilis: a systematic review and meta-analysis.

OBJECTIVE: To systematically assess the diagnostic accuracy of CXCL13 testing of cerebrospinal fluid (CSF) for neurosyphilis diagnosing. DESIGN: Systematic review and meta-analysis. DATA SOURCES: PubMed, Embase, Cochrane Library and Web of Science databases from their inception until 1 May 2023. ELIGIBILITY CRITERIA: Both cross-sectional and case-control diagnostic test studies evaluating the diagnostic value of CSF CXCL13 in diagnosing neurosyphilis were included, with no language restrictions. DATA EXTRACTION AND SYNTHESIS: Two researchers extracted data independently from all finally included articles. The updated Quality Assessment of Diagnostic Accuracy Studies tool was used to assess the quality of the included studies. Quantitative synthesis was done using a bivariate random-effects model. RESULTS: This meta-analysis included seven eligible studies involving a total of 1152 patients with syphilis and 430 patients with neurosyphilis. The pooled sensitivity, specificity and summary area under the curve (AUC) of CSF CXCL13 testing for the diagnosis of neurosyphilis were 0.76 (95% CI 0.64 to 0.85; I2=82%), 0.83 (95% CI 0.80 to 0.85; I2=32.29%) and 0.84 (95% CI 0.81 to 0.87), respectively. Sensitivity analysis confirmed the stability of the combined results. Meta-regression analysis revealed that the heterogeneity of pooled sensitivity was related to different study regions; subgroup analysis indicated that the diagnostic value of CSF CXCL13 testing reported in studies from China was superior to that reported in non-Chinese studies (pooled sensitivity, specificity and summary AUC values were 0.84 (I2=0) vs 0.64 (I2=79.53%), 0.83 (I2=42.03%) vs 0.83 (I2=32.87%) and 0.87 vs 0.83, respectively). The diagnostic value reported in studies with a sample size ≥200, unclassified neurosyphilis and HIV-negative subgroups was superior to the total combined value. CONCLUSIONS: This meta-analysis has demonstrated a reasonable level of accuracy for diagnosis of neurosyphilis with CSF CXCL13 testing. Further multicentre, prospective diagnostic studies, especially in asymptomatic neurosyphilis and HIV-infected patients, are needed to provide more evidence for evaluation before clinical application. PROSPERO REGISTRATION NUMBER: CRD42023414212.

ADAMTS5 Promotes Permeability of the Blood-Brain Barrier during Treponema pallidum Subspecies pallidum Invading the Central Nervous System.

The pathogenesis of neurosyphilis remains unclear. A previous study found a noteworthy up-regulation of a disintegrin and metalloproteinase with thrombospondin type 1 motif 5 (ADAMTS5) gene in human brain microvascular endothelial cells cocultured with Treponema pallidum subspecies pallidum (Tp). To investigate the ADAMTS5 role in Tp invading the central nervous system (CNS), we conducted relevant experiments. Our study revealed that Tp caused an increase in human cortical microvascular endothelial cell/D3 (hCMEC/D3) barrier permeability and significantly enhanced ADAMTS5 expression. The heightened permeability of the hCMEC/D3 barrier was effectively mitigated by inhibiting ADAMTS5. During this process, Tp promoted interleukin-1ß production, which, in turn, facilitated ADAMTS5 expression. Furthermore, Tp significantly reduced the glycocalyx on the surface of hCMEC/D3 cells, which was also ameliorated by inhibiting ADAMTS5. Additionally, ADAMTS5 and endothelial glycocalyx components notably increased in the cerebrospinal fluid of HIV-negative neurosyphilis patients. This research provided the first demonstration of the ADAMTS5 role in Tp invading the CNS and offered new insight into neurosyphilis pathogenesis.