Screening for serum antineuronal antibodies in pediatric epilepsy

Autoimmunity has been associated with epilepsy, either as the cause or consequence of seizures. This study evaluated serum neuronal autoantibodies in pediatric focal epilepsy and assessed the utility of the Antibody Prevalence in Epilepsy (APE) score in identifying potential immune-mediated cases.

Forty-four pediatric patients with focal epilepsy were tested for serum antibodies against NMDA-R, LGI1, CASPR2, GABABR, AMPAR, and GAD65. Two etiological groups were formed according to clinical and neuroimaging features: Group-1 (n = 20) with known structural/genetic etiologies; Group-2 (n = 24) with acquired/remote symptomatic epilepsy with possible secondary autoimmune mechanisms (e.g., hippocampal sclerosis, history of encephalitis/hypoxia). APE scores were calculated using clinical, electroencephalographic, neuroimaging data; cerebrospinal fluid (CSF) parameters were not included.

The age at seizure onset and evaluation and epilepsy duration were similar between groups. No specific neuronal antibodies were identified in any patient. Low-titer anti-GAD antibodies were observed in five patients across both groups and were considered clinically irrelevant. The median APE score was significantly higher in Group-2 (p = 0.030). Four patients (16.7%) in Group-2 had an APE score ≥ 4 whereas none in Group-1.

Routine serum screening with standard commercial antibody panel did not identify neuronal antibodies in this pediatric cohort with chronic focal epilepsy. APE score distinguished patients with possible immune etiologies, suggesting that validated clinical scoring systems assist in selecting patients who may benefit from antibody screening in clinical practice.