High frequency of intrathecal immunoglobulin synthesis in epilepsy so far classified cryptogenic

The influence of the immune system on seizures and epileptogenesis has been increasingly considered, in particular the role of autoantibodies. In this study, we aimed to determine the frequency of intrathecal antibody synthesis in the cerebrospinal fluid (CSF) compartment of patients with epilepsy.

In a retrospective cohort study trial in a university hospital neurology department, 164 well-characterized patients with different etiologies of seizures and epilepsies, and 77 control patients were included.

CSF-specific immunoglobulin (IgG, IgM and IgA) synthesis was significantly (P < 0.0001) more frequent in patients with epilepsy (34.1%) compared with age- and sex-matched controls (2.6%). The highest incidence of intrathecal Ig synthesis was detected in patients with encephalitis-related acute symptomatic seizures (86.7%), but also in patients with focal epilepsy so far classified cryptogenic (45.2%). Antibody synthesis was not related to the number of CSF white blood cells.

Humoral immune activation in the CSF compartment was detected in one-third of patients with epilepsy, besides acute symptomatic seizures particularly frequent in cryptogenic epilepsy--an etiology so far defined as not having a detectable cause. Systematic prospective clinical and experimental trials are required to identify antigenic targets and select appropriate patients for which immunotherapy might offer new causal therapeutic options.