INDIVIDUAL TEST 996
GFAp Antibodies (IgG)
Indication Investigation on suspicion of autoimmune CNS-diseasesMethod Cell-based assay (CBA); indirect immunofluorescence on GFAp transfected cells. The method is not yet validated for clinical laboratory routine diagnostics
Answer The result is reported as negative or positive.
Interpretation Autoantibodies against GFAp have been reported in autoimmune CNS disease with meningo-encephalo-myelitis or parts thereof and are referred to as GFAp astrocyte disease. Symptoms of encephalopathy with epileptic seizures, meningism, headache, cognitive impairment (memory disturbance, confusion) and myelopathy are described as most common. Also, optic edema with blurred vision (often without pain) may occur and area posterior syndrome has been reported.
In a recent report from The Mayo Clinic, 88% of 102 patients with anti-GFAp had ovious cell proliferation in CSF with mononuclear cell dominance (range 13-550 x106 / L) and just over 50% had oligoclonal bands. The presence of anti-GFAp may occur isolated but is detected together with anti-NMDAR-antibodies in about 20% and with anti-AQP4-antibodies in about 10% of cases. Usually, adults are affected, but 10% of reported cases are children. Anti-GFAp can appear para-malignant and is detected a couple of years before known cancer diagnosis.
Antibodies against GFAp are graded as Lower-risk antibodies with a frequency of approximately 20% of underlying cancer and a positive result yield 0 points PNS score, according to Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.
References
- Wei, P., Zhang, W., Yang, L. et al., Serum GFAP autoantibody as an ELISA-detectable glioma marker. Tumor Biol. 34, 2283–2292 (2013). PMID: 23589055
- Fang B. et al., Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy: A Novel Meningoencephalomyelitis. JAMA Neurol. 2016 Nov 1;73(11):1297-1307. PMID: 27618707
- Shan F. et al., Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy: A Review of the Literature. Front Immunol. 2018 Dec 5;9:2802. PMID: 30568655
- Kunchok A. et al., Autoimmune glial fibrillary acidic protein astrocytopathy. Curr Opin Neurol. 2019 Jun;32(3):452-458. PMID: 30724768
- 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 996
GFAp-antikroppar (IgG)
Indikation Utredning vid misstanke om autoimmun CNS-sjukdomMetod Cell-based assay (CBA); indirekt immunofluorescens på GFAp-transfekterade celler. Metoden är ännu inte validerad för klinisk rutindiagnostik.
Svar Resultatet rapporteras som negativt eller positivt.
Tolkning Autoantikroppar mot GFAp har rapporterats vid autoimmun CNS-sjukdom med meningo-encefalo-myelit eller delar därav och benämns GFAp-astrocyt-sjukdom. Symtom på encefalopati med epileptiska anfall, meningism, huvudvärk, kognitiv påverkan (minnesrubbning, konfusion) och myelopati beskrivs vara vanligast. Även optikus ödem med suddig syn (ofta utan smärta) kan förekomma och area postrema syndrom har rapporterats.
I en färsk rapport från The Mayo Clinic hade 88% av 102 patienter med anti-GFAp påtaglig cellstegring i likvor med dominans av mononukleära celler (range 13–550 x 106/L) och drygt 50% hade oligoklonala band.
Förekomst av anti-GFAp kan förekomma isolerat men påvisas tillsammans med anti-NMDAR-ak i ca 20% och med anti-AQP4 i ca 10% av fallen. Vanligtvis drabbas vuxna, men 10% av rapporterade fall är barn. Anti-GFAp kan förekomma paramalignt och påvisas ett par år före känd cancerdiagnos.
Antikropparna riktade mot GFAp bedöms vara Lower-risk antibodies med en förekomst på ca 20% för en underliggande cancer och positivitet ger 0 poäng i PNS score enligt Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.
Referenser
- Wei, P., Zhang, W., Yang, L. et al., Serum GFAP autoantibody as an ELISA-detectable glioma marker. Tumor Biol. 34, 2283–2292 (2013). PMID: 23589055
- Fang B. et al., Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy: A Novel Meningoencephalomyelitis. JAMA Neurol. 2016 Nov 1;73(11):1297-1307. PMID: 27618707
- Shan F. et al., Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy: A Review of the Literature. Front Immunol. 2018 Dec 5;9:2802. PMID: 30568655
- Kunchok A. et al., Autoimmune glial fibrillary acidic protein astrocytopathy. Curr Opin Neurol. 2019 Jun;32(3):452-458. PMID: 30724768
- Graus F, et al. Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes. Neurol Neuroimmunol Neuroinflamm. 2021 May 18;8(4):e1014. PMID: 34006622