CXCL13 in cerebrospinal fluid aids in neurosyphilis diagnosis

Evaluation of CXCL13 concentration in cerebrospinal fluid (CSF) shows good diagnostic accuracy for neurosyphilis, according to the results of a systematic review and meta-analysis.

Researchers searched multiple online databases for cross-sectional and case–control diagnostic test studies, wherein the diagnostic value of CSF CXCL13 for neurosyphilis was evaluated. There were no language restrictions.

Of the 61 articles initially identified, seven articles published in English were included in the meta-analysis. The studies were conducted in China (n=4), US (n=2), and the Netherlands (n=1). The updated Quality Assessment of Diagnostic Accuracy Studies tool was used to assess the quality of the eligible studies, and quantitative synthesis was conducted using a bivariate random-effects model.

The total study population comprised 1,582 participants, of which 1,152 had syphilis (non-neurosyphilis) and 430 had neurosyphilis. Four studies exclusively involved HIV-negative patients, while one study specifically examined HIV-positive patients. The diagnostic thresholds of CXCL13 testing in CSF ranged from 4.871 to 256.4 pg/mL.

Pooled data showed that CSF CXCL13 testing had a sensitivity of 0.76 (95 percent confidence interval [CI], 0.64–0.85; I²=82 percent), specificity of 0.83 (95 percent CI, 0.80–0.85; I²=32.29 percent), and summary area under the curve (AUC) of 0.84 (95 percent CI, 0.81–0.87). Results were robust to sensitivity analysis.

Meta-regression analysis indicated heterogeneity in sensitivity across different study regions. The diagnostic value of CSF CXCL13 testing reported in studies from China was superior to that reported in non-Chinese studies (sensitivity: 0.84 vs 0.640; specificity: 0.83 vs 0.83; summary AUC: 0.87 vs 0.83). Finally, the diagnostic value reported in studies with a sample size of at least 200, unclassified neurosyphilis, and HIV-negative subgroups was superior to the total combined value.