Diagnostic characteristics and literature review of anti-dipeptidyl-peptidase-like protein 6 antibody associated encephalitis
Lin Lirong1, Hao Hongjun2
1Department of Neurology, Inner Mongolia Baogang Hospital, Baotou 014010, China; 2Department of Neurology, Peking University First Hospital, Beijing 100034, China
Abstract：ObjectiveTo explore the diagnostic characteristics of anti-dipeptidyl-peptidase-like protein 6 (DPPX) antibody associated encephalitis. MethodsA retrospective analysis was conducted on the past and current clinical data of a patient with serum anti-DPPX antibody positive admitted to the Neurology Department of Inner Mongolia Baogang Hospital on June 25, 2021. The diagnostic characteristics of anti-DPPX antibody related encephalitis were summarized and relevant literatures were reviewed. ResultsThe patient, a 53 year old male, was hospitalized due to progressive blindness in the right eye for 10 days. Ophthalmic examination showed that the pupils of both sides had unequal sizes, 3.0mm on the left side and 4.0mm on the right side, and the direct and indirect light reflection of right eye disappeared. Light perception of right eye disappeared, and the vision of the left eye was 0.4. The fundus, macular area and fundus fluorescein showed no abnormality. Visual evoked response in the right eye was not elicited. No new infarctions or occupying lesions were found on cranial MRI. The dynamic electroencephalogram was generally normal. Serum anti-DPPX antibody ++(diluted at 1∶20 titers), all other N-methyl-D-aspartic acid (NMDA) receptors encephalitis antibodies were negative. The remaining items of the cerebrospinal fluid examination were generally normal. During hospitalization, nutritional nerve therapy was given, and after 6 days of hospitalization, the lower field of vision and light perception recovered and there was a sense of light. The discharge diagnosis was anti-DPPX antibody encephalitis. The patient was admitted to the hospital for treatment on March 8, 2018 due to left limb strength. At the time of admission, a neurological examination showed that the left limb strength was level 4, with reduced pain sensation in the left upper limb and negative results on other examinations. Complete cranial MRI showed no new infarctions. Neck MRI showed a intramedually mass at the C5/6 level of the neck, diagnosed as astrocytoma. No special treatment was given, and only self rehabilitation exercise was performed. In March 2020, the left limb strength and sensation fully returned to normal. ConclusionThe patient with anti-DPPX antibody encephalitis in this case started with weak unilateral limb strength, and both clinical symptoms showed varying degrees of self relief, further proving that the disease may exhibit self-limiting characteristics.
