Alpha-Synuclein as a Potential Biomarker for Inclusion Body Myositis in Blood and Muscle

Area of Science:

• Neurology
• Biochemistry
• Immunohistochemistry

Background:

• Inclusion body myositis (IBM) diagnosis is challenging, relying on clinical and histological data.
• Biomarkers are needed to improve diagnostic accuracy.
• Alpha-synuclein (αSN) aggregates are observed in IBM histology, but their diagnostic utility and serum levels are underexplored.

Purpose of the Study:

• To investigate the diagnostic relevance of αSN aggregates in IBM biopsies.
• To determine serum αSN concentrations in IBM patients.
• To explore the correlation between serum αSN and disease parameters.

Main Methods:

• Immunohistochemical staining for αSN on muscle biopsies from IBM, other myopathies, and controls.
• Quantification of αSN-reactive fibers.
• Serum αSN concentration measurement using ELISA in IBM, other myopathies, and controls.

Main Results:

• Significantly higher αSN-positive fibers in IBM biopsies compared to all other groups (p < 0.001).
• αSN staining demonstrated 79% sensitivity and 85% specificity for IBM diagnosis.
• Serum αSN concentrations did not differ from controls but inversely correlated with disease duration and positively with functional rating scale, decreasing in late-stage patients.

Conclusions:

• αSN reactivity in muscle biopsies may serve as an additional immunohistochemical marker for IBM diagnosis.
• Serum αSN concentrations decrease with disease duration and clinical deterioration in IBM.
• Serum αSN shows potential as a provisional monitoring biomarker for IBM, requiring further investigation.