INDIVIDUAL TEST 118
mGluR5 Antibodies (IgG)
Indication Suspicion of autoimmune encephalitis.Method Cell-based assay (CBA) with indirect immunofluorescence
Result Reported as positive (with titre) or negative.
Interpretation Metabotropic glutamate receptors are transmembrane proteins in neuronal membranes. Unlike ionotropic receptors, metabotropic glutamate receptors (mGluRs) are not ion channels. Instead, they activate biochemical cascades, leading to the modification of other proteins, as for example ion channels.
Antibodies against mGluR5 (metabotropic glutamate receptor 5) have been reported in limbic encephalitis with (or without) Hodgkin's lymphoma (Ophelia syndrome). Recognition of this disorder is important since it can affect young individuals and is reversible.
It is recommended to use the test on serum. It has not been reported cases of only CSF positive.
Antibodies against mGlur5 are graded as Intermediate-risk antibodies with a frequency of approximately 50% of underlying cancer and a positive result yield 2 points PNS score, according to Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.
References
- Levite M. Glutamate receptor antibodies in neurological diseases: anti-AMPA-GluR3 antibodies, anti-NMDA-NR1 antibodies, anti-NMDA-NR2A/B antibodies, anti-mGluR1 antibodies or anti-mGluR5 antibodies are present in subpopulations of patients with either: epilepsy, encephalitis, cerebellar ataxia, systemic lupus erythematosus (SLE) and neuropsychiatric SLE, Sjogren's syndrome, schizophrenia, mania or stroke. These autoimmune anti-glutamate receptor antibodies can bind neurons in few brain regions, activate glutamate receptors, decrease glutamate receptor's expression, impair glutamate-induced signaling and function, activate blood brain barrier endothelial cells, kill neurons, damage the brain, induce behavioral/psychiatric/cognitive abnormalities and ataxia in animal models, and can be removed or silenced in some patients by immunotherapy. J Neural Transm (Vienna). 2014 Aug;121(8):1029-75. PMID: 25081016.
- Ancona C et al. Autoimmune Encephalitis and Other Neurological Syndromes With Rare Neuronal Surface Antibodies in Children: A Systematic Literature Review. Front Pediatr. 2022 Apr 20;10:866074. PMID: 35515348
- Spatola M et al. Encephalitis with mGluR5 antibodies: Symptoms and antibody effects. Neurology. 2018 May 29;90(22):e1964-e1972. PMID: 29703767
- Graus F, et al. Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes. Neurol Neuroimmunol Neuroinflamm. 2021 May 18;8(4):e1014. PMID: 34006622
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ENSKILD ANALYS 118
mGlur5-antikroppar (IgG)
Indikation Misstanke om autoimmun encefalit.Metod Cell-based assay (CBA) med indirekt immunofluorescens
Svar Anges som positiv (med titer) eller negativ.
Tolkning Metabotropiska glutamatreceptorer är transmembranproteiner i neuronala membran. Till skillnad från jonotropa receptorer är metabotropa glutamatreceptorer (mGluRs) inte jonkanaler. I stället aktiverar de biokemiska kaskader, vilket leder till modifieringen av andra proteiner, såsom exempelvis jonkanaler.
Antikroppar mot mGluR5 (metabotropic glutamate receptor 5) kan förekomma vid limbisk encefalit med (eller utan) Hodgkins lymfom (Ophelia syndrom). Diagnostik av denna sjukdom är viktig eftersom den kan påverka unga individer och är reversibel.
Rekommendationen är att endast testa i serum. Det har inte rapporterats fall som endast har varit positiv i CSF.
Antikropparna riktade mot mGlur5 bedöms vara Intermediate-risk antibodies med en förekomst på ca 50% för en underliggande cancer och positivitet ger 2 poäng i PNS score enligt Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.
Referenser
- Levite M. Glutamate receptor antibodies in neurological diseases: anti-AMPA-GluR3 antibodies, anti-NMDA-NR1 antibodies, anti-NMDA-NR2A/B antibodies, anti-mGluR1 antibodies or anti-mGluR5 antibodies are present in subpopulations of patients with either: epilepsy, encephalitis, cerebellar ataxia, systemic lupus erythematosus (SLE) and neuropsychiatric SLE, Sjogren's syndrome, schizophrenia, mania or stroke. These autoimmune anti-glutamate receptor antibodies can bind neurons in few brain regions, activate glutamate receptors, decrease glutamate receptor's expression, impair glutamate-induced signaling and function, activate blood brain barrier endothelial cells, kill neurons, damage the brain, induce behavioral/psychiatric/cognitive abnormalities and ataxia in animal models, and can be removed or silenced in some patients by immunotherapy. J Neural Transm (Vienna). 2014 Aug;121(8):1029-75. PMID: 25081016.
- Ancona C et al. Autoimmune Encephalitis and Other Neurological Syndromes With Rare Neuronal Surface Antibodies in Children: A Systematic Literature Review. Front Pediatr. 2022 Apr 20;10:866074. PMID: 35515348
- Spatola M et al. Encephalitis with mGluR5 antibodies: Symptoms and antibody effects. Neurology. 2018 May 29;90(22):e1964-e1972. PMID: 29703767
- Graus F, et al. Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes. Neurol Neuroimmunol Neuroinflamm. 2021 May 18;8(4):e1014. PMID: 34006622