Characteristics of epilepsy and immunological markers in epileptic patients after infl uenza associated encephalopathy

ABSTRACT

Objective: This study aimed to elucidate the electro-clinical characteristics of epilepsy and immunological markers in patients with epilepsy after infl uenza-associated encephalopathy/encephalitis (IAE). Methods: Eighteen patients with epilepsy after IAE (8 males, 10 females; mean age of onset 6.4±6.4 years) were studied. Antibodies to glutamate receptor (GluR) ε2 (NR2B) were examined by immunoblot and ELISA. Cytokines were measured by BioPlex. Results: Mean interval between IAE and epilepsy onset was 63.2 ± 95.0 days (mean ± SD). In 16 of 18 patients, complex partial seizures were observed. Most complex partial seizures were of short durations and showed few lateralizing signs. Interictal discharges were seen in the frontal area in 7 of 14 patients. Ictal EEG showed rapid propagation to bilateral hemispheres. Patients with higher cerebrospinal fl uid levels of anti-GluRε2 antibodies, higher cerebrospinal fl uid levels of IL-1β, soluble tumor necrosis factor receptor 1 and IFN-γ during chronic stage, had higher frequency of epileptic seizures. Conclusion: This study indicates that the frontal lobes are susceptible to rapid epileptogenesis after IAE, and that epileptic partial seizures after IAE had characteristics resembling generalized seizures. Presence of anti-GluRε2 antibodies and elevated IL-1β, TNFα, and IFN-γ in cerebrospinal fl uid may be associated with intractability of epileptic seizures.