Anti-NMDAR Antibodies: Autoimmune Mediators of Encephalitis

Molecular Structure and Target Recognition

Anti-NMDAR (N-methyl-D-aspartate receptor) antibodies are autoantibodies that target specific components of the NMDA receptor, particularly:

• GluN1 subunit (primary target)
• Conformational epitopes
• Extracellular domains

These antibodies are predominantly IgG class, with IgG1 and IgG3 subclasses being the most common. Their binding leads to:

• Receptor crosslinking
• Internalization of NMDA receptors
• Reduction in synaptic NMDAR density

Pathophysiological Mechanisms

Receptor Interaction

The antibodies affect NMDA receptor function through multiple mechanisms:

Direct Effects: Receptor internalization, Decreased receptor density, Altered synaptic plasticity

Synaptic Changes: Reduced glutamatergic transmission, Disrupted synaptic function, Impaired long-term potentiation

Neurological Impact

The presence of these antibodies leads to:

• Disrupted neurotransmitter signalling
• Altered neural network function
• Compromised synaptic plasticity
• Neuroinflammatory responses

Clinical Manifestations

Anti-NMDAR Encephalitis

Early Symptoms: Psychiatric manifestations, Behavioural changes, Memory deficits, Anxiety and agitation

Progressive Symptoms: Seizures, Movement disorders, Autonomic instability, Decreased consciousness

Associated Conditions

The antibodies are often associated with:

• Ovarian teratomas
• Other autoimmune disorders
• Viral infections
• Paraneoplastic syndromes

Diagnostic Approaches

Laboratory Testing

CSF Analysis: Antibody detection, Inflammatory markers, Cell count and protein levels

Serum Testing: Antibody titters, Immunological markers, Inflammatory indicators

Imaging Studies

1. MRI brain imaging
2. PET scanning
3. EEG monitoring

Treatment Strategies and Prognosis

First-Line Treatments

Immunotherapy: Corticosteroids, Intravenous immunoglobulins, Plasma exchange

Tumor Removal: When applicable (especially teratomas), Surgical intervention, post-operative monitoring

Second-Line Treatments

For refractory cases:

• Rituximab
• Cyclophosphamide
• Other immunosuppressants

Monitoring and Follow-up

Regular assessment of:

• Clinical improvement
• Antibody levels
• Cognitive function
• Neurological status

Research continues to expand our knowledge of:

• Pathogenic mechanisms
• Novel treatment approaches
• Long-term outcomes
• Prevention strategies

The prognosis varies but is generally favourable with early intervention. Recovery can be prolonged, requiring months to years of treatment and rehabilitation.

Suitable ELISA Kits

• Anti-NMDAR Antibody ELISA Kit
• Anti-N-Methyl-D-Aspartic Acid Receptor Antibody ELISA Kit