Indication Suspicion of paraneoplastic syndrome (especially Stiff person syndrome) and autoimmune encephalitis.
Method Immunoblot and indirect immunofluorescence (IIF).
According to guidelines, anti-neuronal antibodies should be detected by at least two independent methods. At Wieslab, IIF and immunoblot are used. According to European guidelines, a positive result should be obtained with both methods to be reliable.
Result Serum: The result is reported as negative, borderline or positive with a IIF titer and blot intensity.
CSF: The result is reported as negative, borderline or positive.
Interpretation Antibodies against Amphiphysin occur in patients with paraneoplastic variant Stiff person syndrome but can also be seen in autoimmune encephalitis. Antibodies against Amphiphysin are associated with breast cancer and small cell lung cancer. Neurological symptoms may precede the diagnosis of cancer with up to five years.
Antibodies against Amphiphysin are graded as High-risk antibodies with a frequency of 80% of underlying cancer and a positive result yield 3 points PNS score, according to Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.
References
Lancaster E, Martinez-Hernandez E, Dalmau J. Encephalitis and antibodies to synaptic and neuronal cell surface proteins. Neurology. 2011 Jul 12;77(2):179-89. PMID: 21747075
Balint B, Vincent A, Meinck HM, Irani SR, Bhatia KP. Movement disorders with neuronal antibodies: syndromic approach, genetic parallels and pathophysiology. Brain. 2018 Jan 1;141(1):13-36. PMID: 29053777
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 730
Amphiphysin-antikroppar (IgG)
Indikation Misstanke om paraneoplastiska syndrom (speciellt Stiff person syndrome) och autoimmun encefalit.
Metod Immunoblot samt indirekt immunofluorescens (IIF).
Enligt riktlinjer ska anti-neuronala antikroppar detekteras med minst två oberoende metoder. På Wieslab används IIF och immunoblot. Enligt europeiska riktlinjer ska positivt resultat uppnås med båda metoderna för att vara tillförlitligt.
Svar Serum: Resultatet anges som negativt, gränsvärde eller positivt med IIF titer och blot intensitet.
Likvor: Resultatet anges som negativt, gränsvärde eller positivt.
Tolkning Antikroppar mot Amfifysin förekommer hos patienter med den paraneoplastiska varianten av Stiff person syndrom men kan även ses vid autoimmun encefalit och är associerade med bröstcancer och småcellig lungcancer. Neurologiska symtom kan föregå cancerdiagnosen med upp till 5 år.
Antikropparna riktade mot Amfifysin bedöms vara High-risk antibodies med en förekomst på 80% för en underliggande cancer och positivitet ger 3 poäng i PNS score enligt Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.
Referenser
Lancaster E, Martinez-Hernandez E, Dalmau J. Encephalitis and antibodies to synaptic and neuronal cell surface proteins. Neurology. 2011 Jul 12;77(2):179-89. PMID: 21747075
Balint B, Vincent A, Meinck HM, Irani SR, Bhatia KP. Movement disorders with neuronal antibodies: syndromic approach, genetic parallels and pathophysiology. Brain. 2018 Jan 1;141(1):13-36. PMID: 29053777
Graus F, et al. Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes. Neurol Neuroimmunol Neuroinflamm. 2021 May 18;8(4):e1014. PMID: 34006622