Assessment of the YKL-40 concentration in patients with tick-borne encephalitis

Abstract Background Tick-Borne Encephalitis (TBE) is a viral infection of the Central Nervous System (CNS) caused by Tick-Borne Encephalitis Virus (TBEV). It might take several clinical courses such as: meningitis, meningoencephalitis or meningoencephalomyelitis. The aim this study was to compare the YKL-40 concentration in cerebrospinal fluid (CSF) of patients with different clinical presentations of TBE and patients with excluded meningitis (control group). Methods The concentration of YKL-40 in CSF was determined using Fujirebio tests (Ghent, Belgium) in 32 patients with TBE: group I—patients with meningoencephalitis (n = 16); group II—patients with meningitis (n = 16). The control group (CG) consisted of 17 patients in whom inflammatory process in central nervous system was excluded. Results The concentration of YKL-40 was significantly higher in encephalitis group than in CG after 7 days from the last dose of treatment. The concentration in patients with neuroinflammation had significantly different concentration of YKL-40 compared to patients with no neuroinflammation control groups. ROC curve analysis indicates that: CSF YKL-40 concentration at cut off 783.87 differentiated TBE patients from CG with 100% specificity and 70% sensitivity and CSF YKL-40 concentration at cut off 980.11 differentiated meningitis from meningoencephalitis with 87.5% specificity and 62.5% sensitivity. Conclusions YKL-40 takes part in TBE pathogenesis, its concentration is the highest at the early stage of Central Nervous System involvement and decreases in the convalescent period. As YKL-40 is significantly higher in meningitis than in meningoencephalitis, it might be used as biomarker in differentiation of these clinical forms of TBE.