NK cell peak after seizures

Local and systemic immunological alterations may affect the course of focal epilepsy. However, little is known about the influence of seizures on the cellular immunity which we analyzed prospectively in epilepsy patients during video EEG monitoring.

Methods: The distribution of different leukocyte subsets and the serum level of epinephrine was measured immediately and 24 hours after seizures compared to baseline values. Twenty-two patients (age 36.6±10.8 years, 11 male) with temporal lobe epilepsy, who were admitted to prolonged video EEG monitoring as part of their presurgical evaluation, were included. Leukocyte subsets were identified in peripheral blood by FACS analysis. Serum epinephrine was determined by HPLC. Non-parametrical statistics were performed.

Results: In the immediate postictal state (10±6 minutes), there was a significant increase of total leukocytes (42%, p=0.0004), neutrophils (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 significantly decreased by 13% (p=0.0113). These postictal changes remained statistically significant when considering only patients with complex partial seizures (n=17). The changes were more pronounced after secondary generalized tonic-clonic seizures and in patients with hippocampal sclerosis. Treatment with valproic acid (VPA) on admission 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% in patients without LEV, p=0.016). 24 hours after the seizures the alterations had resolved.

Conclusion: There is a pronounced immune response immediately after generalized tonic-clonic and after complex partial seizures which were not accompanied by significant physical activity. These changes may have been mediated by epinephrine release. Mesial temporal lobe epilepsy due to hippocampal sclerosis showed the greatest immune response. This may reflect the close relationship between mesial temporal structures and the hypothalamic-pituitary-adrenal axis. Valproic acid and levetiracetam appeared to influence the cellular immunity.