[Recent changes in the paradigm of limbic encephalitis].

Area of Science:

• Neurology
• Immunology
• Pathogenesis of Neurological Disorders

Background:

• Recent studies identify novel antibodies linked to limbic encephalitis targeting extracellular receptors and proteins involved in hereditary and degenerative diseases.
• Antibodies against LGI1, a trans-synaptic scaffolding protein, are implicated in cases previously attributed to voltage-gated potassium channel (VGKC) antibodies.
• Antibody responses against NMDA-receptors are a significant cause of limbic encephalitis, particularly in young females, and can be triggered by ovarian teratomas.

Purpose of the Study:

• To review and summarize the current understanding of novel antibodies associated with limbic encephalitis.
• To differentiate the mechanisms and prognoses of autoimmune encephalitis caused by antibodies against surface versus intracellular targets.

Main Methods:

• Review of recent literature on antibody targets in limbic encephalitis.
• Analysis of clinical syndromes, triggers, and pathogenic mechanisms associated with specific autoantibodies.
• Comparison of disease outcomes based on antibody targets (extracellular vs. intracellular).

Main Results:

• Antibodies against surface proteins (e.g., LGI1, NMDA-receptors, AMPA, GABA) are increasingly recognized in limbic encephalitis.
• These surface protein antibodies can lead to reversible antigen internalization, suggesting treatable disease.
• Classical onconeural antibodies targeting intracellular antigens (anti-Hu, anti-Ta/Ma2, anti-CV2/CRMP5) are rare, associated with broader symptoms, and have a poor prognosis.

Conclusions:

• Autoimmune limbic encephalitis is often driven by antibodies against cell surface neuronal proteins, offering potential therapeutic targets.
• The distinction between antibodies targeting extracellular versus intracellular antigens is crucial for predicting disease course and prognosis in limbic encephalitis.
• Further research into these novel antibody targets is essential for improving diagnosis and treatment strategies for autoimmune encephalitis.