The titre of MuSK autoantibodies is reflective of the clinical improvement observed after B-cell depletion therapy. However, the titre of AChR-specific autoantibodies correlates unsuccessfully with clinical progress.
Regardless of the presence or absence of thymic abnormalities, thymectomy has yet been shown to improve clinical outcomes for patients with MuSK MG. Thymectomy is recommended for patients with AChR MG and early-onset MG.
Patients with MuSK MG respond positively to treatment with rituximab, whereas patients with AChR MG have not consistently shown the same reaction. This divergence in treatment efficacy might be owing to differences in the tissue localisation of B-cell subsets of MG. It might also be owing to the susceptibility of different autoantibody-producing B-cell subsets to anti-CD20 depletion (ie plasmablasts in MuSK MG vs plasma cells in AChR MG, each expressing different levels of CD20).
Learn more about the pathophysiology of MG.
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Cite this: Raghav Govindarajan, Nicholas J. Silvestri. Fast Five Quiz: Pathophysiology of Myasthenia Gravis - Medscape - Sep 15, 2023.