Different relationships between epilepsy syndromes and autoimmune diseases.

ABSTRACT

OBJECTIVE: Our objective was to study the relationship between epilepsy and autoimmune diseases in two different types of epilepsy idiopathic generalized epilepsies (IGEs) and mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). The contribution of the human leukocyte antigen (HLA) system to this relationship was analyzed. METHODS: Adult patients with IGEs and MTLE-HS at a tertiary epilepsy center were consecutively enrolled between January 2016 and December 2020. RESULTS: A total of 664 patients, 422 with IGEs and 242 with MTLE-HS, were included. Patients with IGEs were 15 years younger, on average, than patients with MTLE-HS (p < .001). The frequency of autoimmune diseases was 5.5% (n = 23) and 4.5% (n = 11) in patients with IGEs and MTLE-HS, respectively (p = .716). The mean age of autoimmune disease onset was 20 ± 15.6 years in patients with IGEs and 36.7 ± 16.5 years in patients with MTLE-HS (p < .05). Clinical manifestations of autoimmune diseases preceded epilepsy onset in 30.4% of patients with IGEs (i.e., in early childhood); in the other patients, epilepsy appeared before autoimmune disease onset. In all but one patient with MTLE-HS and autoimmune diseases, the autoimmune diseases appeared after epilepsy onset from adolescence onward. SIGNIFICANCE: Our study indicates two relationship patterns a bidirectional association between IGEs and autoimmune diseases and a unidirectional relationship between MTLE-HS and autoimmune diseases. The involvement of genetic susceptibility factors (such as the HLA system), autoinflammatory mechanisms, female sex, and antiseizure medications in these relationships are discussed.