Screening for DPPX autoantibodies is used in suspected autoimmune encephalitis as well as in encephalomyelopathy of unknown etiology and in progressive stiffness and myoclonus encephalomyelitis (PERM).
Testing for anti-neuronal antibodies against the DPPX protein (Dipeptidyl Aminopeptidase-like Protein 6, a dipeptidyl aminopeptidase-like protein 6) in serum or cerebrospinal fluid (CSF) is of particular importance in the differential diagnosis. DPPX protein is mainly produced in brain tissue and interacts with the KV4 potassium channel. The DPPX protein is an important regulator of membrane viability in hippocampal CA1 pyramidal cells. Antibodies against DPPX can lead to autoimmune encephalitis.
DPPX belongs to the group of extracellular antigens.