The concentration of cell-free DNA in video-EEG patients is dependent on the epilepsy syndrome and duration of epilepsy

Objective: Cell-free DNA (cf-DNA) is a marker of inflammation and cell death. The purpose of the present study was to analyze the role of cf-DNA as a putative biomarker in refractory epilepsy. Methods: Baseline concentration of cf-DNA was measured in the serum of 51 carefully evaluated refractory epilepsy patients undergoing video-EEG monitoring. Epilepsy was classified based on seizure semiology, patient history, and imaging findings. Majority of the patients (47) had focal epilepsy. The association of the concentration cf-DNA with different clinical determinants was analyzed. 250 healthy individuals served as control subjects. Results: The mean baseline concentration of cf-DNA was lower in patients with extra temporal lobe epilepsy (XTLE) compared to control subjects (0.72 mu g/ml vs. 0.80 mu g/ml; p = 0.001). The difference in concentration of cf-DNA between patients with temporal lobe epilepsy (TLE) and control subjects was not significant. The maximum concentration of cf-DNA after baseline measurement was significantly lower in patients with duration of epilepsy >= 18 years compared to those with duration of epilepsy < 18 years (0.022 mu g/ml vs. 0.031 mu g/ml; p = 0.044). The maximum concentration of cf-DNA was higher in patients with body mass index (BMI) >= 25 compared to those with BMI < 25 (0.004 mu g/ml vs. 0.041 mu g/ml; p = 0.006). Discussion: The difference in cf-DNA concentration between patients with XTLE and control subjects strengthens the previous observations of the importance of epilepsy type with regard of different biomarkers.