Autoimmune Encephalitis Screen (NMDAR, CASPR2, LGI1, AMPAR1/2, DPPX and GABA Receptor Antibodies)

Immunology

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Description

Patients with autoimmune encephalopathies may produce autoantibodies targeted towards neuronal surface antigens. Autoimmune encephalitis refers to a group of closely related diseases that share overlapping clinical features and have similar finding on brain imaging. The diseases can be differentiated by the presence of specific autoantibodies [1].

NMDAR (N-Methyl D-aspartate receptor) antibodies are glutamate receptor antibodies which may be associated with NMDA receptor encephalitis.
AMPAR 1 and 2 (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor 1 and 2) antibodies are also glutamate receptor antibodies . AMPAR antibodies can be observed in limbic encephalitis and atypical psychosis. LGI1 (Leucine rich glioma-inactivated protein 1) antibodies and GABA (gamma-aminobutyric acid) receptor antibodies may be also be associated with limbic encephalitis [2,3].

CASPR2 (Contactin-associated Protein 2) antibodies can be seen in limbic encephalitis, neuromyotonia and Morvan’s syndrome [2,3].

DPPX (Dipeptidyl-peptidase-like protein-6) is a subunit of the potassium channel. Antibodies to DPPX have been reported in patients with an encephalitis picture plus severe diarrhoea and weight loss that can precede the encephalitis. This can be found in both adults and children.

The conditions present with symptoms such as seizures, confusion and other neuropsychiatric manifestations. Patients may have non-paraneoplastic or paraneoplastic associations. Diagnosis is usually made using a combination of clinical features, imaging and autoantibody detection. Early treatment results in considerable reduction of symptoms in most patients (1, 2, 3).

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Sample Type

2mL Serum (Gel 5mL Yellow tube) or CSF. Requests from outside Sheffield: Transport at ambient temperature via Royal Mail or Courier.

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Reference Range

Negative = Normal

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Testing Frequency

Weekly

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References

Kelley BP, Patel SC, Marin HL, et al. Autoimmune Encephalitis: Pathophysiology and Imaging review of an overlooked diagnosis. American Journal of Neuroradiology. 2017. 38(6):1070-1078. [Ref 1] Lee SK. Lee ST. The laboratory diagnosis of autoimmune encephalitis. Journal of Epliepsy research. 2016. 6(2):45-52. [Ref 2]. Lancaster E. The diagnosis and treatment of autoimmune encephalitis. 2016. 12(1):1-13. [Ref 3].

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See Also

Cerebellar antibodies; NMDAR Antibodies; VGKC Antibodies

Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.