Autoimmune-associated epilepsy: definitions and diagnosis – a narrative review

Autoimmune-associated epilepsy (AAE) is an increasingly-recognized condition in which seizures result from immune-mediated mechanisms, such as Rasmussen's encephalitis and antibody-associated epilepsies. Its timely identification may enable more efficacious therapy and improve outcomes. The current paper aims to provide a clinically-oriented review of AAE, focusing on clinical identification, use of diagnostic scoring systems, and immunological testing strategies. Antibody-associated epilepsy encompasses a broad spectrum of presentations, from postencephalitic epilepsy to isolated drug-resistant temporal-lobe epilepsy. Neuronal-surface autoantibodies (such as anti-N-methyl-D-aspartate receptor (anti-NMDAR), anti- leucine-rich glioma-inactivated protein 1 (anti-LGI1), anti-CASPR2) and intracellular antibodies (such as anti-GAD65) are variably associated with pathogenesis and chronicity. Clinical scoring systems (such as Antibody Prevalence in Epilepsy and Encephalopathy - APE2, Antibody Contributing to Focal Epilepsy Signs and Symptoms - ACES, ntibody Prevalence in Epilepsy before Surgery - APES, Antibody in Drug-Resistant Temporal Lobe Epilepsy - ARTE and 'Obvious' Indications for Neural Antibody Testing in Epilepsy or Seizures - ONES) are helpful in selecting patients for autoantibody testing. A comprehensive workup includes magnetic resonance imaging (MRI) scans, prolonged electroencephalographic (EEG) monitoring, cerebrospinal fluid (CSF) analysis, and combined serum/CSF antibody panels. Testing methodology and antibody type must be carefully interpreted in the light of clinical context. In low-resource settings, cost-effective testing strategies and clinical-screening tools are crucial to optimize the diagnostic yield. Early clinical suspicion, guided use of diagnostic scores, and appropriate immunological investigation are central to manage AAE. Recognizing AAE as a distinct diagnostic category is essential to improve care and guide immunotherapeutic decisions.