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 Ma antigen is available in two variants: Ma-1 and Ma-2. In the past, anti-Ma-1 antibodies have also been reported as a separate analysis, but studies have shown that it is antibodies against Ma-2 that are relevant for the paraneoplastic neurological syndrome. Ma-2 is also referred to as Ta. Occurrence is associated to paraneoplastic cerebellar degeneration, limbic encephalitis and brain stem encephalitis. These antibodies can occur in many different forms of cancer, such as breast cancer, testis cancer and small cell lung cancer. Neurological symptoms can precede cancer diagnosis by up to 5 year.
Antibodies against Ma are graded as High-risk antibodies with a frequency of >75% 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
Ortega Suero G, Sola-Valls N, Escudero D, Saiz A, Graus F. Anti-Ma and anti-Ma2-associated paraneoplastic neurological syndromes. Neurologia (Engl Ed). 2018 Jan-Feb;33(1):18-27. English, Spanish. doi: 10.1016/j.nrl.2016.05.010. Epub 2016 Jul 25. PMID: 27460184.
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 790
Ma (Ma-2/Ta)-antikroppar (IgG)
Indikation Misstanke om paraneoplastiska syndrom.
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 Ma antigenet finns i två olika varianter: Ma-1 och Ma-2. Tidigare har även anti-Ma-1 antikroppar svarats ut som separat analys, men studier har visat att det är antikroppar mot Ma-2 som är relevant vid paraneoplastiska neurologiska syndrom. Ma-2 benämns även som Ta. Förekomst är associerat med paraneoplastisk cerebellär degeneration, limbisk encefalit och hjärnstamsencefalit. De kan förekomma vid många olika cancerformer, t. ex. bröstcancer, testiscancer och småcellig lungcancer. Neurologiska symtom kan föregå cancerdiagnos med upp till 5 år.
Antikropparna riktade mot Ma bedöms vara High-risk antibodies med en förkomst på >75% 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
Ortega Suero G, Sola-Valls N, Escudero D, Saiz A, Graus F. Anti-Ma and anti-Ma2-associated paraneoplastic neurological syndromes. Neurologia (Engl Ed). 2018 Jan-Feb;33(1):18-27. English, Spanish. doi: 10.1016/j.nrl.2016.05.010. Epub 2016 Jul 25. PMID: 27460184.
Graus F, et al. Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes. Neurol Neuroimmunol Neuroinflamm. 2021 May 18;8(4):e1014. PMID: 34006622