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Topic: Autoimmune neurological diseases associated with
Review
autoantibodies specific for synaptic antigens

Encephalitis associated with autoantibody binding

to the anti‑N‑methyl‑D‑aspartate receptor:

immunopathogenesis, mechanisms, and clinical

characteristics

Adhasit Nawa‑apisak, Saharat Aungsumart, Metha Apiwattanakul

Department of Neurology, Neuroimmunology Unit, Prasat Neurological Institute, Bangkok 10400, Thailand.
A B S T R AC T

Anti‑N‑methyl‑D‑aspartate receptor (NMDAR) encephalitis has been increasingly recognized in recent years. This condition
may be the most common cause of antibody‑mediated encephalitis worldwide. The majority of patients are young at the time
of onset, female, and present with an acute‑to‑subacute onset of behavioral changes followed by seizure, abnormal movement,
autonomic dysfunction, and finally hypoventilation with coma if left untreated. The immunopathogenesis of this disease may be
due to antibody‑mediated internalization of NMDARs from synapses, which results in the dysfunction of particular brain regions
(especially the hippocampus and frontostriatal area). Compared to serum, the cerebrospinal fluid permits the more sensitive
detection of anti‑NMDAR antibody. Ovarian teratoma may be present in up to 40% of patients but is less frequent in children or
late‑onset disease (> 45 years old). The severity at the time of disease onset and time to appropriate immunotherapy (high‑dose
steroid plus plasmapheresis or intravenous immunoglobulin) are independent factors that are associated with good outcomes.
Key words: Abnormal movement; anti‑N‑methyl‑D‑aspartate receptors encephalitis; glutamate; immunotherapy; ovarian teratoma;
psychiatric symptoms; seizure

INTRODUCTION (aged 18‑35 years) who were admitted to an intensive
care unit with encephalitis of an unknown etiology
The N‑methyl‑D‑aspartate receptors (NMDAR) are (excluding infectious causes). The data obtained
[2]
glutamatergic ion channels that are widely expressed from a population‑based prospective study in England
in both cortical and subcortical areas of the brain. showed that 4% of all cases of encephalitis presented
[3]
These receptors are essential in memory and behavior. anti‑NMDAR antibody. In the California Encephalitis
[4]
Hyperactivity of NMDAR may be the underlying Project, anti‑NMDAR encephalitis was identified
mechanism of seizure and some types of dyskinesia, in 4% of patients < 30 years of age with encephalitis
and under activity may be related to schizophrenia. [1] of an uncertain etiology, and it was detected 4 times
more frequently than herpes simplex virus type 1
Anti‑NMDAR encephalitis has been increasingly encephalitis, West Nile virus, or Varicella zoster
recognized in recent years. The exact incidence of virus encephalitis. Anti‑NMDAR encephalitis was
anti‑NMDAR encephalitis is unknown. Data from also the most common cause of antibody‑mediated
a retrospective study indicated that anti‑NMDAR encephalitis. There is no information regarding
encephalitis represented 1% of all young patients the incidence of anti‑NMDAR encephalitis in Asia.
However, in Japan, a condition called acute juvenile
Corresponding Author: Dr. Metha Apiwattanakul, Department female nonherpetic encephalitis (AJFNHE) is almost
of Neurology, Neuroimmunology Unit, Prasat Neurological
Institute 312, Rajavithee Road, Bangkok 10400, Thailand. This is an open access article distributed under the terms of the Creative
E‑mail: apiwattanakul.metha@gmail.com Commons Attribution‑NonCommercial‑ShareAlike 3.0 License, which allows
others to remix, tweak, and build upon the work non‑commercially, as long as the
Access this article online author is credited and the new creations are licensed under the identical terms.
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Website:
http://nnjournal.net
Cite this article as: Nawa-apisak A, Aungsumart S, Apiwattanakul
M. Encephalitis associated with autoantibody binding to the
DOI: anti-N-methyl-D-aspartate receptor: immunopathogenesis, mechanisms,
10.4103/2347-8659.169913 and clinical characteristics. Neuroimmunol Neuroinflammation 2016;3:79-85.
Received: 21-01-2015; Accepted:13-04-2015

© 2016 Neuroimmunology and Neuroinflammation | Published by OAE Publishing Inc. 79