Autoimmune epilepsies

To review the recent literature describing the detection and clinical importance of serum antibodies in patients with various epilepsies and other seizure-related disorders.

Auto-antibodies to the NMDA, GABAB and AMPA receptors and to LGI1, CASPR2 and Contactin-2, components of the voltage-gated potassium channel complex, have been detected in the serum of patients with seizures. These antigenic targets are ion channels, receptors and accessory proteins important in both cellular homeostasis and governing the electrical activity of the brain. Antibodies to glutamic acid decarboxylase (GAD) have been found in patients with temporal lobe epilepsy. Antibodies to LGI1 have been described in around 90% of patients with the newly described epileptic syndrome of faciobrachial dystonic seizures.

An increasing number of antibodies have been described in the epilepsies and other seizure-related disorders. Evidence of direct pathogenicity comes from the extracellular domain targeted by all of these antibodies (other than GAD) and the often dramatic clinical and serological response to immunotherapies, when antiepileptic drugs may be ineffective. Definitive proof as to the pathological relevance of these antibodies will be achieved in the generation of an animal model that demonstrates the clinical phenotype of these antibody-mediated disorders.