Evaluation of CXCL12 Diagnostic Performance in Tick-Borne Encephalitis and Other Central Nervous System Infections

CXCL12 is a chemokine acting via CXCR4 that plays a key role in inflammatory processes by regulating leukocyte migration and immune responses, making it an important focus of research in neuroinfections. In this study, the CXCL12 chemokine was evaluated as a potential diagnostic marker of different neuroinfections with particular emphasis on tick-borne encephalitis (TBE). A group of 214 patients with confirmed meningitis and/or encephalitis was included and divided according to etiology into TBE, aseptic meningitis, neuroborreliosis, and purulent meningitis. CXCL12 concentration and other inflammatory parameters were measured in cerebrospinal fluid (CSF). CXCL12 levels were compared with those of controls (N = 25) and analyzed statistically. In addition, serum was used to determine albumin concentrations. CXCL12 concentrations were significantly higher in patients with neuroinfections compared to controls and showed good diagnostic performance in the overall study group (AUC = 0.791), with a more moderate diagnostic performance observed in individual etiological groups, except in the purulent meningitis group, where the effect was not statistically significant, likely due to the small sample size. CXCL12 also demonstrated some utility in differentiating between specific etiologies; however, this effect was limited. Better diagnostic performance was observed when CXCL12 was combined with pleocytosis in a composite model differentiating between the TBE group and aseptic meningitis (AUC = 0.761). The presented results indicate the role of CXCL12 in neuroinflammation while simultaneously highlighting its potential in the development of novel diagnostic approaches for viral neuroinfections. Despite higher levels in TBE, its standalone diagnostic value is limited; however, it may enhance diagnostic accuracy when combined with other markers such as pleocytosis.