Abstracts

Rationale: Autoimmunity has been an emerging point of research in the etiology of different neurological disorders including epilepsy(1). We aimed to search for autoantibodies against GAD, LGI1, CASPR2, NMDA, AMPA and GABA receptors and investigate the clinical presentation as well as the risk factors which can be correlated with autoimmune etiology. These are the preliminary results of our ongoing study.Methods: Patients with cryptogenic epilepsy attending to outpatient epilepsy clinic at Neurology Department, Cerrahpasa Faculty of Medicine were included. Patient demographics, age at seizure onset, seizure frequency, risk factors, seizure precipitants, type of seizures were noted. Plasma obtained from patients was frozen at -80 C and analyzed for autoantibodies against LGI1, CASPR2, NMDA, AMPA, GABA receptors and GAD with immunocytochemistry techniques, ELISA method or radioimmunoassay technique as required. Positive samples were confirmed by immunohistochemistry and western blotting. Results: There were 36 patients (17 women) diagnosed with cryptogenic epilepsy. Mean age of the patients were 33.2 years (range 8- 82yr). Except for nine, all patients had focal seizures (15 temporal lobe epilepsy- TLE). Mean age at onset of seizures was 23.5yrs (range 4 months- 61yr), duration of epilepsy was 9.72 years (range 1week-50yr). Patient history revealed various infections (7), allergic disorders (4 pt), febrile seizures (2 pt), antiphospholipid syndrome with systemic lupus erythematosus (1 pt), diabetes mellitus (1 pt) gastric cancer (1 pt), and pernicious anemia (1 pt). Fifteen of them had nocturnal seizures and 5 experienced status epilepticus. Seizures were precipitated during infectious diseases in 9, menstruation in 5, and sleep deprivation in 4 and stress in 3 patients. Anti GAD antibodies were detected in 3 of 8 patients studied whereas in none of the 36 patients autoantibodies against LGI1, CASPR2, NMDA, AMPA, GABA receptors was detected. Further evaluation of these 3 anti GAD positive patients revealed past history of febrile seizures, allergic disease and Hashimato encephalitis. Two patients suffered from focal and one from generalized seizures with onset 48, 21 and 8 years respectively. MRI did not show any structural abnormality and all were on two antiepileptic drugs with partial control.Conclusions: The preliminary data achieved from this ongoing study is not adequate for firm conclusions yet, however careful analyses of antibody positive patients may enable us to define a subgroup of patients with cryptogenic etiology which may improve our understanding of immune system related etiology and may induce a new therapeutic interventions in specific patient populations. References: 1. Prevalence of neurologic autoantibodies in cohorts of patients with new and established epilepsy Brenner T, Sills GJ, Hart Y, Howell S, Waters P, Brodie MJ, Vincent A, Lang B. Epilepsia. 2013 Jun; 54(6):1028-35.