Indicators of inflammation after recent tonic–clonic epileptic seizures correlate with plasma interleukin-6 levels

Cerebrospinal fluid (CSF) and peripheral blood pleocytosis have been observed after epileptic seizures without any evidence of infections, but no systematic studies on the acute phase reaction in such patients have been performed. We have previously reported increased levels of interleukin-6 (IL-6) in patients with recent tonic--clonic seizures. Because IL-6 is a major inducer of the systemic acute phase reaction, we decided to study various indicators of inflammation in the blood as well as their correlation with plasma and CSF IL-6 levels. CSF and blood samples were studied from 37 patients with previously undiagnosed and untreated tonic-clonic seizures without any clinical evidence of systemic or central nervous system infections as well as from 40 controls. The mean peripheral blood and CSF-leukocyte counts were significantly higher in patients compared with controls ( 7.9 x 10(9)vs. 6.1 x 10(9), P= 0.002 and 1.9 x 10(6)vs. 1.1 x 10(6), P= 0.032, respectively). There was some indication of increased concentration of C-reactive protein (CRP) and no difference in haptoglobin levels. There was a significant correlation between plasma but not CSF IL-6 concentration and those of both B-leukocyte count ( r= 0.051, P= 0.009) and CRP ( r= 0.42, P= 0.009). Epileptic seizures provoke a production of cytokines such as IL-6 that may in turn cause an activation of the acute phase reaction. Thus, CSF pleocytosis and increase in some indicators of inflammation should not automatically be attributed to systemic or CNS infections in patients with acute seizures.