Effective Treatment of Anti-GAD65 Limbic Encephalitis-Associated Epilepsy Despite Delayed Immunotherapy: A Brief Report.

A 44-year-old woman was referred to our epilepsy center for evaluation of refractory seizures persisting for 36 years. Diagnostic workup revealed anti-glutamic acid decarboxylase 65 limbic encephalitis (anti-GAD65 LE), supported by markedly elevated serum anti-GAD65 antibody titers and a compatible clinical presentation. Following initiation of a 6-month course of intravenous immunoglobulin (IVIG), seizure frequency decreased substantially, from 12 to 16 focal seizures per day to approximately one brief focal seizure per month. This was accompanied by improvements in cognition, psychiatric symptoms, and overall clinical function. This case highlights the potential for meaningful therapeutic response to immunotherapy despite prolonged diagnostic delay.