Monovalent and pathogenic muscle-specific kinase antibodies in myasthenia gravis

Takeaway

  • Fab-arm exchange of immunoglobulin (Ig)G4 muscle-specific kinase (MuSK) antibodies (Abs) renders them functionally monovalent and this contributes to the pathogenesis of MuSK myasthenia gravis (MG).

Why this matters

  • This study presents a newly identified pathomechanism in antibody-mediated autoimmunity that is unique to IgG4; multiple other autoimmune diseases are hallmarked by pathogenic IgG4, therefore, this pathomechanism may also be relevant to the pathogenesis of other diseases as well as MuSK MG.