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.

Beyond T cell toxicity - Intrathecal chemokine CXCL13 indicating B cell involvement in immune-related adverse events following checkpoint inhibition: A two-case series and literature review.

BACKGROUND AND PURPOSE: This study was undertaken to raise awareness of a role of B cells in immune checkpoint inhibitor (ICI)-associated neurological immune-related adverse events (nirAE). METHODS: A systematic literature review was made, with case observations of a melanoma and a non-small cell lung cancer (NSCLC) patient who developed ICI-associated nirAE with cerebrospinal fluid (CSF) findings indicating B cell involvement. RESULTS: Two patients receiving ipilimumab/nivolumab for melanoma and chemotherapy/pembrolizumab for NSCLC developed nirAE in the form of myocarditis/myositis/myasthenia gravis overlap syndrome (triple M) and cerebellitis plus longitudinal transverse myelitis (c-LETM), respectively. Intrathecal inflammation with chemokine C-X-C motif ligand (CXCL13) elevation was present in both patients; the triple M case had acetylcholine receptor antibodies, antititin reactivity, altered CD4/CD8 T cell ratio in blood, and depressed programmed death-1 (PD-1) expression on CSF T cells; the c-LETM case showed intrathecal antibody production and plasma cells. Both patients insufficiently responded to first-line treatment. The NSCLC case improved upon administration of B cell-depleting therapy with rituximab, whereas the melanoma patient died before escalation therapy was initiated. Literature research revealed one additional ICI-associated LETM case with intrathecal CXCL13 elevation, three cases with ICI-associated aquaporin-4 antibody neuromyelitis spectrum disorder, and evidence of B cell-mediated toxicity based on antibody-mediated immune pathologies in ICI-associated immune-related adverse events. CONCLUSIONS: The case observations highlight the plethora of uncertainties in diagnosis and treatment of ICI-associated nirAE, exemplify the heterogeneity of immune mechanisms involved, and suggest a role of B cells, which may be underdiagnosed. Intrathecal CXCL13 may serve as a biomarker of B cell involvement in nirAE, supported by intrathecal immunoglobulin synthesis, presence of plasma cells, and/or recruitment of cognate immune cells.

Prognostic relevance of the C-X-C motif chemokine ligand 13 and interleukin-8 in predicting the transition from clinically isolated syndrome to multiple sclerosis.

The initial phase of multiple sclerosis (MS), often known as clinically isolated syndrome (CIS), is a critical period for identifying individuals at high risk of progressing to full-blown MS and initiating timely treatment. In this study, we aimed to evaluate the prognostic value of C-X-C motif chemokine ligand 13 (CXCL13) and interleukin-8 (IL-8) as potential markers for CIS patients' conversion to MS. Our study encompassed patients with CIS, those with relapsing-remitting MS (RRMS), and control subjects, with sample analysis conducted on both cerebrospinal fluid (CSF) and serum. Patients were categorized into four groups: CIS-CIS (no MS development within 2 years), CIS-RRMS (conversion to RRMS within 2 years), RRMS (already diagnosed), and a control group (CG) with noninflammatory central nervous system disorders. Results showed significantly elevated levels of CXCL13 in CSF across all patient groups compared with the CG (p < 0.0001, Kruskal-Wallis test). Although CXCL13 concentrations were slightly higher in the CIS-RRMS group, statistical significance was not reached. Similarly, significantly higher levels of IL-8 were detected in CSF samples from all patient groups compared with the CG (p < 0.0001, Kruskal-Wallis test). Receiver operating characteristic analysis in the CIS-RRMS group identified both CXCL13 (area under receiver operating characteristic curve = .959) and IL-8 (area under receiver operating characteristic curve = .939) in CSF as significant predictors of CIS to RRMS conversion. In conclusion, our study suggests a trend towards elevated CSF IL-8 and CSF CXCL13 levels in CIS patients progressing to RRMS. These findings emphasize the importance of identifying prognostic markers to guide appropriate treatment strategies for individuals in the early stages of MS.