Autoantibodies against glutamate receptors in patients with encephalitis

: We examined autoantibodies against GluRepsilon2 in patients with acute encephalitis, who were categorized into localized encephalitis and widespread encephalitis. Patients with localized encephalitis are defined as patients showing psychic symptoms (illusions, anxiety and distraction etc.), solitary seizures and/or very mild impairment of consciousness in the initial stage. Patients with widespread encephalitis are defined as patients showing a profound loss of consciousness and or convulsive status in the initial stage. In 24 patients with localized encephalitis, immunoglobulin (Ig) M autoantibodies against GluRepsilon2 tended to appear in CSF in the acute stage (0-20 days after onset of neurological symptoms) or recovery stage (21-60 days after onset of neurological symptoms) of encephalitis. In 22 patients with widespread encephalitis, IgM autoantibodies against GluRepsilon2 in CSF tended to appear in the recovery stage (21-60 days after onset of neurological symptoms) or chronic stage (>60 days after onset of neurological symptoms) of encephalitis. All patients with localized encephalitis had autoantibodies to the extracellular N epitope. However, no patients with widespread encephalitis had autoantibodies to the extracellular N epitope in acute stages. These data may suggest that GluR autoimmunity contributes to the onset of localized encephalitis.