Autoimmune and inflammatory epilepsies

The role of immunity and inflammation in epilepsy have long been suggested by the anticonvulsant activity of steroids in some infancy and childhood epilepsies. The role of fever and infection in exacerbating seizures due to possible proinflammatory molecules, the increased frequency of seizures in systemic autoimmune diseases like systemic lupus erythematous, and, recently, the detection of autoantibodies in some unexplained epilepsies reinforced the causal place of immunity and inflammation in epilepsies with unknown etiology. In this article, we summarize epilepsies where clinical and biologic data strongly support the pathogenic role of autoantibodies (e.g., limbic encephalitides, N-methyl-d-aspartate [NMDA] encephalitis) and epilepsies where immune-mediated inflammation occurs, but the full pathogenic cascade is either not clear (e.g., Rasmussen's encephalitis) or only strongly hypothesized (idiopathic hemiconvulsion-hemiplegia syndrome [IHHS] and fever-induced refractory epilepsy in school-aged children [FIRES]). We emphasize the electroclinical features that would help to diagnose these conditions, allowing early immunomodulating therapy. Finally, we raise some questions that remain unclear regarding diagnosis, mechanisms, and future therapies.