DPPX (dipeptidyl aminopeptidase-like protein 6) antibodies

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..

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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

Acute test