Method Indirect immunofluorescence (IIF) using transfected cells.
Result The result is reported as positive or negative. A positive result is followed by a titer (serum).
Interpretation Analysis for anti-neuronal antibodies against DPPX (dipeptidyl aminopeptidase-like protein 6) in patient serum or CSF are of particular importance in differential diagnosis of encephalitis. DPPX, which is mainly produced in brain tissue, interacts with the KV4 potassium channel. DPPX is an important regulator of membrane viability in hippocampus CA1 pyramid cells. Antibodies against DPPX can lead to autoimmune encephalitis.
DPPX belongs to the group of extracellular antigens. Generally, immunotherapy is more often effective in autoantibodies directed against extracellular antigens than in autoantibodies against intracellular antigens.
Antibodies against DPPX are graded as Lower-risk antibodies with a frequency of <10% of underlying cancer and a positive result yields 0 points PNS score, according to Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.
References
Boronat A et al. Encephalitis and antibodies to dipeptidyl-peptidase-like protein-6, a subunit of Kv4.2 potassium channels. Ann Neurol 73 (2013) 120-128. PMID:23225603
Lancaster E, Martinez-Hernandez E, Dalmau J. Encephalitis and antibodies to synaptic and neuronal cell surface proteins. Neurology 77 (2011) 179-189. PMID: 21747075
Frank Leypoldt, et.al. “Autoimmune encephalopathies” Ann. N.Y. Acad. Sci. (2014) 1–21. PMID 25315420
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;
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 851
DPPX-antikroppar (IgG)
Indikation Misstanke om autoimmun encefalit.
Metod Indirekt immunofluorescens (IIF) med transfekterade celler.
Svar Resultatet anges som positiv eller negativ. Positivt resultat titreras (serum).
Tolkning Analys av anti-neuronala antikroppar mot DPPX (dipeptidylaminopeptidas liknande protein 6) i patientserum eller likvor är av intresse vid differentialdiagnos av encefalit. DPPX som huvudsakligen produceras i hjärnvävnad, interagerar med kaliumkanalen KV4. DPPX är en viktig reglerare av membranens retbarhet i hippocampus CA1 pyramidceller. Antikroppar mot DPPX kan leda till autoimmun encefalit.
DPPX räknas till gruppen extracellulära antigen. Generellt sett är behandling med immunoterapi oftare effektiv vid autoantikroppar riktade mot extracellulära antigen än vid autoantikroppar mot intracellulära antigen.
Antikropparna riktade mot DPPX bedöms vara Lower-risk antibodies med en förekomst på <10% för en underliggande cancer och positivitet ger 0 poäng i PNS score enligt Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes
Referenser
Boronat A et al. Encephalitis and antibodies to dipeptidyl-peptidase-like protein-6, a subunit of Kv4.2 potassium channels. Ann Neurol 73 (2013) 120-128. PMID:23225603
Lancaster E, Martinez-Hernandez E, Dalmau J. Encephalitis and antibodies to synaptic and neuronal cell surface proteins. Neurology 77 (2011) 179-189. PMID: 21747075
Frank Leypoldt, et.al. “Autoimmune encephalopathies” Ann. N.Y. Acad. Sci. (2014) 1–21. PMID 25315420
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;
Graus F, et al. Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes. Neurol Neuroimmunol Neuroinflamm. 2021 May 18;8(4):e1014. PMID: 34006622