Clinical characteristics and treatment of patients with overlapping MOG and anti-NMDAR encephalitis

Abstract

Objective: This study aimed to investigate clinical manifestations, cerebrospinal fluid (CSF) profiles, neuroimaging characteristics, and treatment responses in patients demonstrating concurrent NMDAR antibody (NMDAR-ab) positivity in CSF and MOG antibody (MOG-ab) seropositivity. Methods: A retrospective study was conducted on patients with dual MOG-ab and anti-NMDAR antibody positivity treated at the Department of Neurology and Pediatrics, First Affiliated Hospital of Zhengzhou University (September 2019-July 2023). Participants were categorized into three groups: overlapping antibody group, isolated anti-NMDAR encephalitis, and MOG antibody-associated disease (MOGAD). Results: Thirteen patients with antibody overlap presented with encephalitis spectrum symptoms including fever (53.8%), headache (61.5%), altered consciousness (46.2%), neuropsychiatric disturbances (38.5%), and seizures (23.1%) at disease onset. Cranial MRI revealed cortical/subcortical involvement in 30.8% of cases, with leptomeningeal enhancement observed in 22.2%. Acute-phase treatment predominantly included intravenous methylprednisolone (IVMP) and intravenous immunoglobulin (IVIG). Median modified Rankin Scale (mRS) scores improved significantly from 2 (IQR: 1-2.5) pre-treatment to 1 (IQR: 0.5-1) post-treatment. Compared to MOGAD controls, overlap adult patients exhibited higher ICU admission rates (30.8% vs. 6.7%), increased frequency of neuropsychiatric symptoms (38.5% vs. 6.7%), and lesser cortical/subcortical MRI abnormalities (30.8% vs. 64.4%), with reduced gadolinium enhancement (22.2% vs. 68.2%, P < 0.05). Distinct from isolated anti-NMDAR encephalitis, overlap cases demonstrated lower rates of neuropsychiatric disturbances (38.5% vs. 83.3%) and seizures (23.1% vs. 62.5%), but higher incidence of brachium pontis MRI abnormalities (23.1% vs. 0.0%, P < 0.05). Kaplan-Meier analysis over 6–48 months follow-up showed no significant difference in relapse rates between the overlapping antibody group and the MOGAD group or the anti-NMDAR encephalitis group (log-rank P > 0.05). Conclusion: Demographic characteristics and oncological associations were comparable across groups. Overlap cases demonstrated unique clinico-radiological profiles with predominant cortical/subcortical involvement and reduced meningeal enhancement. Neuroimaging evidence of brachium pontis abnormalities in anti-NMDAR encephalitis warrants MOG-ab testing. This Asian cohort demonstrates distinct clinical trajectories compared to Western series, emphasizing the need for regional diagnostic considerations.