Indication
Suspicion of autoimmune encephalitis.
Method
Indirect immunofluorescence (IIF) using transfected cells.
Response
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..
References
Boronat A, Gelfand JM, Gresa-Arribas N, Jeong HY, Walsh M, Roberts K, Martinez-Hernandez E, Rosenfeld MR, Balice-Gordon R, Graus F, Rudy B, Dalmau J. 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
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.
Referenser
Boronat A, Gelfand JM, Gresa-Arribas N, Jeong HY, Walsh M, Roberts K, Martinez-Hernandez E, Rosenfeld MR, Balice-Gordon R, Graus F, Rudy B, Dalmau J. 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