Clinical Report: Encephalitis with Coexisting Anti-NMDAR and Anti-MOG Antibodies

Overview

This report presents a case of overlapping syndrome (MNOS) involving anti-NMDAR and anti-MOG antibodies with concurrent cytomegalovirus (CMV) infection in cerebrospinal fluid. The patient's treatment included antiviral agents, corticosteroids, and intravenous immunoglobulin.

Background

The coexistence of anti-NMDAR and anti-MOG antibodies is a rare phenomenon known as overlapping syndrome (MNOS), which has been associated with viral infections in some cases. Cytomegalovirus (CMV) is a common virus that can lead to significant neurological complications.

Data Highlights

Metagenomic next-generation sequencing of cerebrospinal fluid identified CMV DNA with high confidence (specific reads: 362; relative abundance: 85.97%).

Key Findings

• The patient was a previously healthy 49-year-old male who developed acute neuropsychiatric symptoms following a viral prodrome.
• CSF analysis revealed elevated opening pressure and pleocytosis with a white blood cell count of 60×106/L.
• Anti-NMDAR antibodies and anti-MOG antibodies were detected in the CSF, while only anti-MOG antibodies were found in serum.
• The patient was treated with antiviral agents, corticosteroids, and intravenous immunoglobulin.

Clinical Implications

This case highlights the importance of considering viral infections in patients presenting with symptoms of autoimmune encephalitis. Clinicians should maintain a high index of suspicion for overlapping syndromes in similar clinical scenarios.

Conclusion

The detection of CMV in the CSF of a patient with MNOS underscores the potential link between viral infections and autoimmune encephalitis. Further research is warranted to explore this relationship.

Related Resources & Content

1. Frontiers in Immunology, 2026 -- Triple antibody-associated autoimmune encephalitis overlap: a case report of co-existing MOG-IgG, anti-NMDAR, and anti-mGluR5 positivity
2. Frontiers in Immunology, 2026 -- Myelin oligodendrocyte glycoprotein antibody-associated disease presenting as encephalitis and concurrent Epstein-Barr virus detection: a case series
3. Nature Reviews Disease Primers, 2025 -- Autoimmune encephalitis
4. ScienceDirect, 2025 -- Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD): Practical recommendations for diagnosis and management
5. PubMed, 2025 -- The spectrum of overlapping anti-NMDAR encephalitis and demyelinating syndromes: a systematic review of presentation, diagnosis, management, and outcomes
6. Brain — Neuro-immunobiology and treatment assessment in a mouse model of anti-NMDAR encephalitis
7. Acta Neuropathologica — Neuronal pSTAT1 as a Marker of Synaptic Dysfunction in Autoimmune Encephalitis Targeting Intracellular Antigens
8. Autoimmune encephalitis | Nature Reviews Disease Primers
9. Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD): Practical recommendations for diagnosis and management - ScienceDirect
10. The spectrum of overlapping anti-NMDAR encephalitis and demyelinating syndromes: a systematic review of presentation, diagnosis, management, and outcomes - PubMed