VZV brainstem encephalitis triggers NMDA receptor immunoreaction

After its discovery, anti-NMDA receptor (NMDAR) encephalitis was quickly recognized as "sleeping" neurologic disease, presumably heavily underestimated. This autoimmune disease is defined by the presence of immunoglobulin G (IgG) antibodies against cell surface epitopes of the NR1 subunit of the NMDAR.1 The disease phenotype is best characterized as encephalopathy and was initially described by Dalmau et al.2 in young women presenting with a prominent change of behavior, psychosis, memory deficits, seizures, abnormal movements, coma, and autonomic dysfunction. Whereas in cases of an underlying tumor (usually teratoma in the ovary) the cause of the disease is viewed as paraneoplastic, in many cases without a tumor the trigger for the NMDAR antibody production is unknown. Recently it has been observed that herpes simplex virus 1 (HSV-1) may account for relapses of HSV encephalitis (HSVE) by inducing NMDAR immunoreactivity causing the full clinical picture of anti-NMDA-R encephalopathy3 or a choreatic condition.4–6