Antibody Prevalence in Epilepsy and Encephalopathy score: Increased specificity and applicability

To the Editors: In 2017, we validated models to predict seropositivity of neural-specific antibodies and favorable response to an immunotherapy trial among patients with epilepsy.1 The purpose of these models is to optimize selection of cases for autoimmune epilepsy evaluation and management.F I G U R E 1 Autoimmune epilepsy diagnostic criteria stratified as per Antibody Prevalence in Epilepsy and Encephalopathy (APE2) score and neural antibody status.Algorithm is shown for utilization of proposed diagnostic criteria for autoimmune epilepsy diagnosis.CSF, cerebrospinal fluid; MRI, magnetic resonance imaging.a Reasonable exclusion of alternative etiology (genetic, infectious encephalitis, neoplasm, neurodegenerative process, or metabolic or toxic encephalopathy).b One patient with leucine-rich glioma-inactivated protein-1 antibody had APE2 score < 4.He had monophasic clinical course with seizures responding to lacosamide and intravenous methylprednisolone.c Neural-specific antibodies clinically validated to have an association with autoimmune epilepsy (AMPAR [amino-3-hydroxy-5-methyl-4isoxazolepropionic acid receptor], amphiphysin, AK5 [adenylate kinase 5], ANNA1 [antineuronal nuclear antibody 1], ANNA2 [antineuronal nuclear antibody 2], ANNA3 [antineuronal nuclear antibody 3], DPPX [dipeptidyl-peptidase-like protein 6], CASPR2 [contactin associated protein 2], CRMP5 [collapsin response-mediator protein 5], GAD65 [glutamic acid decarboxylase 65, serum >20 nmol•L -1 or CSF-detected], GABABR [γ-aminobutyric acid B receptor], GABAAR [γ-aminobutyric acid A receptor], GFAPα [glial fibrillary acidic protein, CSF-detected], LGI1 [leucine-rich glioma-inactivated protein 1], Ma1/Ma2, MOG [myelin oligodendrocyte glycoprotein], mGluR5 [metabotropic glutamate receptor 5], neurexin-3α, NMDAR [N-methyl D-aspartate receptor, preferably CSF-detected], PCA2 [Purkinje cell antibody type 2], PCA Tr) evaluated and confirmed by the latest validated techniques.dStandardized immunotherapy trials should be considered.Twelve-week intravenous methylprednisolone (IVMP) trial: 1 g, intravenously once per day for 3 consecutive days, then once weekly for 5 weeks, followed by once every 2 weeks for 6 weeks, for a total of 12 weeks of therapy.Six-week IVMP trial: 1 g, intravenously once per day for 3 consecutive days, then once weekly for 5 weeks.Twelve-week intravenous immunoglobulin (IVIG) trial: 0.4 g/kg daily for 3 days followed by 0.4 g/kg every week for 6 weeks and then every 2 weeks for 6 weeks.Sixweek IVIG trial: 0.4 g/kg daily for 3 days followed by 0.4 g/kg every week for 6 weeks.e Favorable outcome is defined as >50% reduction in seizure frequency