INDIVIDUAL TEST 620
Autoimmune Nodopathy/CIDP – Screen IgG
Indication
Suspicion of Inflammatory Neuropathy/Autoimmune Nodopathy that is refractory to standard treatment.
Method
Cell-Based Assay (CBA), Indirect immunofluorescence (IIF) The method is not yet validated for clinical diagnostic use.
Reference interval
Serum: <1:10 negative
Result
Results are reported as negative or positive. A positive result is followed by a titer.
Interpretation
Neurofascin-155 (NF155), Neurofascin-186, Contactin-1 (CNTN1), and Contactin-associated protein 1 (CASPR1) are nodal/paranodal proteins of importance for the function of the node of Ranvier. IgG autoantibodies against NF155, NF186, CNTN, and CASPR1 have been reported in patients with Autoimmune Nodopathy. Autoimmune nodopathies have until recently been regarded as subgroups of CIDP but are distinct in both disease course and treatment, and are now regarded as separate disorders (European Academy of Neurology 2022). The panel is useful for diagnosing autoimmune nodopathies with CIDP-like symptoms and includes testing of the following autoantibodies:
- Neurofascin-155 antibodies (IgG) and Neurofascin-186 antibodies (IgG). Isolated seropositivity of IgG antibodies against NF155 is reported in Autoimmune Nodopathy. For positive test results, subclass determination of (IgG4) is recommended. Autoimmune nodopathy with IgG4 antibodies against NF155 is characterized by a chronic disease course. The simultaneous presence of antibodies against NF186 and NF155 has been reported in acute immune-mediated neuropathy with initial GBS-like symptoms, where patients do not respond well to standard treatment. After an initial improvement, a fulminant rapid disease progression with tetraplegia and autonomous instability development can be seen, which is typical for this type of pan-neurofascin neuropathy..
- Contactin-1 antibodies (IgG). Contactin-1 (CNTN1) is a paranodal protein. IgG-antibodies against Contactin-1 have been reported in autoimmune nodopathy.
- CASPR1 antibodies (IgG). Contactin-associated protein 1 (CASPR1) is a paranodal protein. Antibodies against CASPR1 IgG have been reported in autoimmune nodopathy.
References
Dong M et al. Clin Neurol Neurosurg. 2022. Characterization of the patients with antibodies against nodal-paranodal junction proteins in chronic inflammatory demyelinating polyneuropathy. PMID: 36401951
Querol LA et al. Neurotherapeutics. 2022. The Role of the Complement System in Chronic Inflammatory Demyelinating Polyneuropathy: Implications for Complement-Targeted Therapies. PMID: 35378684
Cortese A et al. Neurol Neuroimmunol Neuroinflamm. 2019. Antibodies to neurofascin, contactin-1, and contactin-associated protein 1 in CIDP: Clinical relevance of IgG isotype. PMID: 31753915
Delmont E et al. Brain. 2017. Autoantibodies to nodal isoforms of neurofascin in chronic inflammatory demyelinating polyneuropathy. PMID: 28575198
Appeltshauser L et al. Brain. 2023. Anti-pan-neurofascin antibodies induce subclass-related complement activation and nodo-paranodal damage. PMID: 36346134
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ENSKILD ANALYS 620
Autoimmun nodopati/CIDP – screen IgG
Indikation
Misstanke om inflammatorisk neuropati/autoimmun nodopati.
Metod
Cell-based assay (CBA), Indirekt immunofluorescens (IIF). Metoden är ännu inte validerad för klinisk diagnostik.
Referensintervall
Serum: <1:10 negativt
Resultat
Resultat anges som negativt eller positivt. Positivt resultat titreras.
Tolkning
Neurofascin-155 (NF155), Neurofascin 186, Contactin-1 (CNTN1) och Contactin associerade protein 1(CASPR1) är nodala/paranodala proteiner som är viktiga för funktionen i Ranviers nod. IgG-antikroppar mot NF155, NF186, CNTN1 och CASPR1 har rapporterats vid Autoimmun nodopati. Dessa sjukdomstillstånd har tidigare ansetts vara undergrupper till CIDP men både förlopp och behandling särskiljer sig och autoimmuna nodopatier definieras numera som distinkta diagnoser (European Academy of Neurology, februari 2023).
Panelen inkluderar analys av följande autoantikroppar som kan vara till hjälp vid utredning av patienter med CIDP-liknande symtom.
- Neurofascin-155-antikroppar (IgG) och Neurofascin-186-antikroppar (IgG). Isolerad förekomst av IgG antikroppar mot NF155 har rapporterats vid autoimmun nodopati och vidare analys med subklassbestämning (IgG4) rekommenderas vid positivt fynd. Autoimmun nodopati med IgG4-antikroppar mot NF155 karakteriseras av ett kroniskt förlopp. Däremot har samtidig förekomst av antikroppar mot NF186 och NF155 rapporterats vid akut immunmedierad neuropati som initialt ter sig som Guillain Barré syndrom (GBS), men svarar dåligt på standardbehandling. Efter initial kortvarig förbättring kan ett fulminant snabbt förlopp med tetraplegi och autonom instabilitet utvecklas snabbt, och anses vara typiskt för denna typ av pan-neurofascin neuropati.
- Contactin-1-antikroppar (IgG). Contactin-1 (CNTN1) är ett paranodalt protein. IgG-antikroppar mot CNTN1 har beskrivits vid autoimmun nodopati.
- CASPR1-antikroppar (IgG). Contactin associated protein 1 (CASPR1) är ett paranodalt protein. Antikroppar mot CASPR1 har beskrivits vid autoimmun nodopati.
Referenser
Dong M et al. Clin Neurol Neurosurg. 2022. Characterization of the patients with antibodies against nodal-paranodal junction proteins in chronic inflammatory demyelinating polyneuropathy. PMID: 36401951
Querol LA et al. Neurotherapeutics. 2022. The Role of the Complement System in Chronic Inflammatory Demyelinating Polyneuropathy: Implications for Complement-Targeted Therapies. PMID: 35378684
Cortese A et al. Neurol Neuroimmunol Neuroinflamm. 2019. Antibodies to neurofascin, contactin-1, and contactin-associated protein 1 in CIDP: Clinical relevance of IgG isotype. PMID: 31753915
Delmont E et al. Brain. 2017. Autoantibodies to nodal isoforms of neurofascin in chronic inflammatory demyelinating polyneuropathy. PMID: 28575198
Appeltshauser L et al. Brain. 2023. Anti-pan-neurofascin antibodies induce subclass-related complement activation and nodo-paranodal damage. PMID: 36346134