INDIVIDUAL TEST 845
VGCC Antibodies
Indication
Suspicion of paraneoplastic neuropathy, Lambert-Eaton myasthenic syndrome and cerebellar dysfunction.
Method
The test is performed in serum and CSF with radioimmunoprecipitation (RIA).
Result
The result is reported as a concentration in pmol/L and as negative or positive.
Reference interval:
VGCC N type <110 pmol/L negative
VGCC P/Q type <40 pmol/L negative.
Interpretation
Calcium channel antibodies occur in paraneoplastic neuropathy in e.g. small cell lung cancer, but even without this association. Causes include Lambert-Eaton myasthenic syndrome and cerebellar dysfunction. It is primarily the VGCC P/Q type antibodies that are of clinical significance while the importance of VGCC N-type antibodies is less known.
Generally, treatment with immunotherapy is more effective against auto-antibodies directed to extracellular antigens than with auto-antibodies against intracellular antigens.
Antibodies against VGCC P/Q are graded as Intermediate-risk antibodies with an frequency of 50% (LEMS ; nearly 90% for rapidly progressive cerebellar syndrome) of underlying cancer and a positive result yield 2 points PNS score, according to Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.
References
- Dalmau J, Geis C, Graus F. Autoantibodies to Synaptic Receptors and Neuronal Cell Surface Proteins in Autoimmune Diseases of the Central Nervous System. Physiol Rev. 2017 Apr;97(2):839-887. PMID: 28298428
- Alexopoulos H, Dalakas MC. The immunobiology of autoimmune encephalitides. J Autoimmun. 2019 Nov;104:102339. PMID: 31611142.
- 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 845
VGCC-antikroppar
Indikation
Misstanke om paraneoplastisk neuropati, Lambert-Eatons myastena syndrom och cerebellär dysfunktion.
Metod
Analysen utförs i serum och likvor med radioimmunoprecipitation (RIA).
Svar
Resultatet anges som en koncentration i pmol/L samt som negativt eller positivt.
Referensintervall:
VGCC N-typ <110 pmol/L negativt
VGCC P/Q-typ <40 pmol/L negativt.
Tolkning
Antikroppar mot spänningsberoende kalciumkanaler (Voltage gated calcium channels, VGCC) förekommer vid paraneoplastisk neuropati vid t.ex småcellig lungcancer, men även utan denna association. Ger upphov till bland annat Lambert-Eatons myastena syndrom och cerebellär dysfunktion. Det är främst VGCC P/Q typ av antikroppar som är kopplade till sjukdom. Signifikansen av N-typ antikroppar är mindre känd.
Generellt sett är behandling med immunoterapi oftare effektfull vid auto-antikroppar riktade mot extracellulära antigen än vid auto-antikroppar mot intracellulära antigen.
Antikropparna riktade mot VGCC P/Q bedöms vara Intermediate-risk antibodies med en förekomst på 50% (vid LEMs; nästan 90% vid snabb progressiv cerebellär syndrom) för en underliggande cancer och positivitet ger 2 poäng i PNS score enligt Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.
Referenser
- Dalmau J, Geis C, Graus F. Autoantibodies to Synaptic Receptors and Neuronal Cell Surface Proteins in Autoimmune Diseases of the Central Nervous System. Physiol Rev. 2017 Apr;97(2):839-887. PMID: 28298428
- Alexopoulos H, Dalakas MC. The immunobiology of autoimmune encephalitides. J Autoimmun. 2019 Nov;104:102339. PMID: 31611142.
- Graus F, et al. Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes. Neurol Neuroimmunol Neuroinflamm. 2021 May 18;8(4):e1014. PMID: 34006622