Cryptogenic Partial Epilepsies with Anti‐GM1 Antibodies: A New Form of Immune‐Mediated Epilepsy?

Summary: Purpose : We wished to study immune system dysfunction which has been proposed as a potential cause of epilepsy. Epileptogenic action of antibodies directed against GM1 gangliosides was demonstrated in rats, but the potential role of anti‐GMI antibodies in human epilepsy has not yet been studied. Methods : We investigated the presence of IgG or IgM anti‐GMI antibodies in the sera of 64 patients with various types of epileptic syndromes: idiopathic generalized epilepsy (ICE) (n = 6), symptomatic or cryptogenic generalized epilepsy (SCGE) (n = 7), symptomatic partial epilepsy (SPE) (n = 26), and cryptogenic partial epilepsy (CPE) (n = 25). Results : Two patients had elevated titers of IgM anti‐ GMl antibodies, one patient had elevated titers of both IgM and IgG anti‐GM1 antibodies, and I patient had elevated titers of IgG anti‐GMI antibodies. All 4 patients had complex partial seizures (CPS) secondarily generalized, generalized, drug resistance, psychiatric disorders, and normal brain imaging. Anti‐GMI antibodies were never associated with ICE, SCGE, or SPE. We compared the reactivity of sera from these patients with the sera from 5 patients with motor neuropathies with conduction block (MNCB) against different gangliosides and concluded that epilepsy sera did not react with the Gal(β1‐3)GalNAc epitope. Two anti‐GM1‐positive patients were treated successfully with high‐dose intravenous immunoglobulins (IgIV). Conclusions : Our findings suggest that detection of anti‐GM1 antibodies could allow identification of a subgroup of patients with partial epilepsy associated with an autoimmune response. If anti‐GM1 antibodies prove pathogenic, they could be an important prognostic factor for drug resistance and worsening of seizures.