GABA B receptor antibodies

Indication

Suspicion of paraneoplastic syndromes particularly in autoimmune encephalitis.

Method

Indirect immunofluorescence (IIF) using transfected cells.

Answer

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

Interpretation

Antibodies against GABA B receptors may occur in classical autoimmune encephalitis. There are relatively few cases published, of which 50% have been women, age when diagnosed between 24-75 years (median 62 years). The antibodies have been associated with small cell lung cancer in 50-60% of the cases. Antibodies may occur together with other autoantibodies in around 50% of the cases (antibodies against GAD-65, VGCC, and TPO).

GABA B receptors belong to the group of extracellular antigens. Generally, immunotherapy is more often effective in autoantibodies directed against extracellular antigens than in autoantibodies against intracellular antigens. Antibody titers can be used to monitor treatment effectiveness. Screening for cancer diagnosis is recommended.

Read more about sampling

References

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

Lancaster, Lai, Peng, et al. Antibodies to the GABA(B) receptor in limbic encephalitis with seizures: case series and characterisation of the antigen. Lancet Neurol 2010;9:67-76. PMID 19962348.

Packages and other tests

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

Own immunologist