NK and CD4+ T cell changes in blood after seizures in temporal lobe epilepsy

Immunological phenomena may affect the course of focal epilepsy. We analyzed prospectively the pre- and postictal distribution of leukocyte subsets in epileptic patients.

Twenty-two patients (age 36.6+/-10.8 years, 50% men) with temporal lobe epilepsy were included. Distribution of leukocyte subsets and serum levels of epinephrine were measured in peripheral blood immediately and 24 h after seizures and compared to baseline values.

In the immediate postictal state (10+/-6 min), we observed a significant relative increase of total leukocytes (42%, p=0.0004), neutrophil leukocytes (55%, p=0.0007), total lymphocytes (45%, p=0.0019), natural killer (NK) cells (104%, p=0.0017), and epinephrine (454%, p=0.0014). CD4(+) T cells decreased by 13% (p=0.0113). These postictal changes remained significant considering only complex partial seizures (n=17). The alterations were more pronounced in patients with hippocampal sclerosis. Treatment with valproic acid (VPA) was accompanied by a greater postictal decrease of CD4(+) T cells (25% compared to 5% in patients without VPA, p=0.041) while treatment with levetiracetam (LEV) correlated with a low postictal increase of NK-like T cells (4% versus 41%, p=0.016). Twenty-four hours after the seizures the alterations had resolved.

Profound postictal changes in the immune cell composition of the peripheral blood may have been mediated by epinephrine release. The greater immune response in patients with mesial temporal lobe epilepsy due to hippocampal sclerosis may reflect a close relationship between mesial temporal structures and the sympathetic nerve system. VPA and LEV may have an impact on seizure induced immunological changes.