Long-Term Outcomes in Antibody-Negative Autoimmune Encephalitis

Seronegative autoimmune encephalitis (AE), characterized by the absence of known neuronal autoantibodies despite meeting clinical criteria, presents significant diagnostic and therapeutic challenges. Although immunotherapy is frequently used, long-term outcomes in this population remain poorly characterized. This systematic review and meta-analysis aims to synthesize evidence on long-term outcomes in seronegative AE, focusing on functional status, seizure burden, cognitive impairment, relapses, immunotherapy practices, and prognostic indicators. We included studies involving patients 12 years or older diagnosed with antibody-negative probable AE (ANPRA), possible AE, or definite limbic encephalitis (LE) with negative neuronal antibodies according to Graus et al. (2016), with a minimum median follow-up of 6 months.