Clinical and laboratory findings of patients with anti-dipeptidyl-peptidase-like protein 6 encephalitis: two cases report / 中华神经科杂志

ABSTRACT

Objective:To identify anti-dipeptidyl-peptidase-like protein 6 (DPPX) antibody in patients with encephalitis of unknown etiology and describe the clinical features of anti-DPPX antibody-associated encephalitis in Chinese patients.Methods:For patients registered in the Peking Union Medical College Hospital Encephalitis and Paraneoplastic Syndrome Registration Project from 2016 to 2019 with negative findings in autoimmune encephalitis routine antibody profile and paraneoplastic antibody profile, but with positive tissue-based assay (TBA) results, further tests for rare antibodies, including cell-based assay (CBA) of anti-DPPX antibody, were performed. Patients positive for anti-DPPX antibody were enrolled and the clinical data were collected.Results:Two patients with anti-DPPX antibody-associated encephalitis were found from 2016 to 2019 among about 15 000 patients. Both were females, aged 46 and 75 years. One patient had diarrhea, cachexia, cognitive dysfunction, agitation, myoclonus, tremor, and seizures. The other had cognitive impairment, restlessness, memory loss, disorientation, and sleep disturbance. The second patient had medical history of systemic lupus erythematosus and secondary Sj?gren′s syndrome.Conclusions:TBA should be combined with CBA in identification of anti-DPPX antibody to confirm the diagnosis. Anti-DPPX antibody-associated encephalitis has clinical manifestations of encephalopathy with diarrhea and cachexia, and can coexist with systemic lupus erythematosus.