Encephalitis is an important clinical component of myelin oligodendrocyte glycoprotein antibody associated demyelination: a single-center cohort study in Shanghai, China

Background and purpose Besides a distinct spectrum of demyelinating syndromes, encephalitis was observed in patients with myelin oligodendrocyte glycoprotein antibodies (MOG-abs). Methods The clinical records of 690 patients with idiopathic demyelinating diseases of the central nervous system seen in our center from June 2015 to December 2017 were retrospectively reviewed. All underwent serum aquaporin 4 antibody (AQP4-ab) and MOG-ab detection by cell-based assays as a routine diagnostic approach. Patients with MOG-abs or AQP4-abs who had ever experienced an encephalitis-like illness during the disease course were identified. Whether diagnoses of possible or definite autoimmune encephalitis could be reached with regard to these particular episodes of encephalitis was determined. The incidence and clinical features of encephalitis in anti-MOG disease are described in detail and compared with those in anti-AQP4 disease. Results Amongst the 690 patients, 87 were MOG-ab-positive whilst 140 were AQP4-ab-positive. 20.7% (18/87) of the MOG-ab-positive patients had typical presentations of encephalitis. Unique cortical lesions (72.2%, 13/18) were observed; fever (55.6%), intracranial hypertension (41.2%) and cerebrospinal fluid pleocytosis (64.7%) were common during MOG-ab-associated encephalitis. Sixteen of the 18 patients fulfilled the criteria of definite autoimmune encephalitis (specific disease with MOG-ab) during encephalitis, and five patients overlapped with anti-N-methyl-d-aspartate-receptor encephalitis (NMDARE). Only 3.6% (5/140) of the AQP4-ab-positive patients had encephalitis, and none overlapped with NMDARE. The Expanded Disability Status Scale scores and the Cerebral Functional System Scores at last follow-up were lower in patients with MOG-ab-associated encephalitis than in those with AQP4-ab-associated encephalitis. Conclusions Encephalitis should be recognized as an important clinical component in anti-MOG diseases.