The authors report a patient with partial and secondarily generalized status epilepticus who required 70 days of general anesthesia for seizure control. Although antiepileptic medications failed to control the seizures, they resolved with plasma exchange. The patient's serum reacted with rat cerebral cortex, hippocampus, and cerebellum, but not with cells expressing the glutamate receptor GluR3. These findings suggest an immune response against neuronal antigens other than GluR3.