Etiology and site of temporal lobe epilepsy influence postictal cytokine release

Abstract

Inflammatory mechanisms are involved in the pathogenesis of epilepsy. Vice versa, immune functions are regulated by the brain. We measured postictal changes in serum levels of the immuno-modulating cytokines IL-1beta, IL-6 and TNFalpha in patients with well-defined temporal lobe epilepsy (TLE) and determined modifying factors. Serum levels of IL-1beta, IL-6 and TNFalpha were quantified by ELISA at baseline as well as immediately, 1h and 24h after a complex partial (CPS) or secondary generalized tonic-clonic seizure (GTCS) during video-EEG monitoring in 25 patients suffering from temporal epilepsy. IL-6 increased by 51% immediately after the seizure (p<0.01) and remained elevated for 24h. This increase lacked in patients with hippocampal sclerosis (HS; n=16, mean increase 28%, p>0.5, vs. 112%, p<0.01 in patients without HS). IL-6 levels were higher after right-sided seizures as compared to left-sided seizures 24h after the seizure (8.7pg/mL vs. 3.4pg/mL, p<0.05). In patients taking valproate (VPA, n=9), the levels of IL-1beta were higher as compared to patients not treated with VPA. The results suggest a relationship between the cytokine system and characteristics of TLE such as side and pathology.