Anti-DPPX Encephalitis: A Potentially Treatable Autoimmune Syndrome

Antibodies against dipeptidyl-peptidase–like protein 6 (DPPX), a regulatory protein of the Kv4.2 potassium channels, have been described recently in patients presenting with central nervous system (CNS) hyperexcitability (e.g., hyperekplexia, myoclonus, tremor, or seizures) with antecedent weight loss and diarrhea, some of whom were found to have systemic lymphoma. Researchers have now retrospectively identified nine patients with anti-DPPX antibodies in the serum or cerebrospinal fluid (CSF) and describe their clinical course along with 30 other cases in the literature. Additional laboratory studies were performed on samples from the nine patients to determine antibody effects on neuronal cell surface DPPX and Kv4.2 channels.

Median age of …