NMDA receptor antibodies

Indication

Suspicion of anti-NMDA receptor encephalitis or for differential diagnosis of autoimmune encephalitis. Epileptic seizures may be an early symptom.

Method

Indirect immunofluorescence using transfected cells.

Response

The result is reported as positive or negative. A positive result is followed by a titer (serum).

Interpretation

Antibodies against the NMDAR (NR1 unit) are indicative of autoimmune encephalitis. NMDAR belongs to the family of ionotropic glutamate receptors and is widely expressed in the temporal lobe (limbic system). Signaling initiated by glutamate binding to the NMDA receptor is important for synaptic plasticity and cognitive functions such as memory and learning. Subacute personality change with cognitive effects, hallucinations, epileptic seizures, bizarre behavior, impaired memory and impaired orientation are examples of symptoms that indicate suspicion of autoimmune encephalitis if infectious cause can be excluded. Autoimmune encephalitis may be associated with malignancy.

NMDAR encephalitis often affects young women but may occur at all ages and in both sexes. NMDAR antibodies can be associated with ovarian teratoma (or testis teratoma for men), reported frequency varies between 9-56%. Early diagnosis and treatment is important, before permanent tissue damage occurs. Antibody titers can be used to monitor treatment effectiveness.

Generally, treatment with immunotherapy is more effective at autoantibodies directed against extracellular antigens than autoantibodies against intracellular antigens. In case of late diagnosis, permanent damage may occur when autoantibodies are considered pathogenic. Long treatment for several months to years duration may be required as well as follow up with cancer diagnosis.

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Referenser: 

Lancaster, Martinez-Hernandez, Dalmau. Encephalitis and antibodies to synaptic and neuronal cell surface proteins. Neurology. 2011 Jul 12;77(2):179-89.  PMID: 21747075.

Titulaera et al. Screening for tumours in paraneoplastic syndromes: report of an EFNS Task Force. European Journal of Neurology. Epublished 2010. Eur J Neurol. 2011 January; 18(1): 19–23. PMID: 20880069.

Zuliani, Graus, Giometto, Bien, Vincent. Central nervous system neuronal surface antibody associated syndromes: review and guidelines for recognition. J Neurol Neurosurg Psychiatry 2012;83:638-645. PMID: 22448032.

Dalmau, Tuzan, Wu et. al. Paraneoplastic anti- N-metyl-D-aspartat receptor encephalitis associated with ovarian teratoma. Ann Neurol 2007;61:25-36. PMID 17262855.

Packages and other tests

View other packages Paraneoplastic Syndromes and Limbic Encephalitis (560, 561 and 562)

20 years experience