Subunit-Specific Immunodominance in Clinically Distinct Populations With AChR+ Myasthenia Gravis: A Multiparametric...

Area of Science:

• Neurology
• Immunology
• Autoimmune Diseases

Background:

• Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder characterized by fluctuating muscle weakness.
• It results from autoantibodies targeting the acetylcholine receptor (AChR) at the neuromuscular junction (NMJ).
• Despite research, MG's heterogeneity and unpredictability necessitate deeper understanding of its pathogenesis.

Purpose of the Study:

• To identify clinical and immunologic parameters correlating with MG disease severity.
• To investigate patterns in disease severity related to patient demographics and immunological markers.

Main Methods:

• A large-scale, multicenter, cross-sectional study of 513 MG patients with positive anti-AChR IgG titers.
• Profiling of subunit-specific anti-AChR IgG titers and analysis of clinical data from 232 patients.
• Investigation of correlations between disease severity and age, sex, onset, thymic involvement, anti-AChR titer, and immunodominance.

Main Results:

• Anti-AChR titers correlated positively with disease severity and were higher in females, decreasing with age in females.
• Male patients showed predominantly alpha-immunodominance, while females exhibited gamma-immunodominance, linked to higher titers and severe disease.
• Principal component analysis revealed two distinct MG endotypes: early-onset, severe female patients (endotype A) and late-onset, less severe male patients (endotype B).

Conclusions:

• Two distinct MG endotypes were identified, differentiated by sex, age, thymic status, antibody levels, and immunodominance.
• These endotypes suggest different underlying etiologies for MG.
• Findings support the development of sex-dependent precision medicine and novel therapeutic strategies for MG.