Case report: Ofatumumab treatment in anti-DPPX autoimmune encephalitis.

ABSTRACT

Dipeptidyl peptidase-like protein 6 (DPPX) antibody encephalitis is a rare autoimmune encephalitis. Diagnosis and treatment of DPPX remain challenging, particularly in patients with refractory disease. Herein, we report the first case of anti-DPPX encephalitis treated with ofatumumab. The patient had a chronic insidious onset and predominantly presented with severe neuropsychiatric symptoms and the typical triad of symptoms (weight loss, central nervous system hyperexcitability, and cognitive dysfunction). Positive anti-DPPX antibodies in the serum (11,000) and cerebrospinal fluid (CSF) (1100) were detected at the disease peak. The patient was unresponsive to four types of standard immunotherapies (intravenous globulin, plasma exchange, steroids, and tacrolimus), resulting in a treatment switch to ofatumumab. After five doses of injection and 12 months of follow-up, the patient improved well, with only a mild cognitive deficit.