Acetylcholine receptors loss and postsynaptic damage in MuSK antibody-positive myasthenia gravis

Ann Neurol. 2005 Feb;57(2):289-93. doi: 10.1002/ana.20341.

Abstract

Muscle-specific tyrosine kinase (MuSK) antibodies are found in some patients with "seronegative" myasthenia gravis (MG), but how they cause myasthenic symptoms is not clear. We visualized acetylcholine receptors (AChRs) and complement component 3 (C3) in muscle biopsies from 10 Japanese MG patients with MuSK antibodies, compared with 42 with AChR antibodies. The AChR density was not significantly decreased in MuSK antibody (Ab)-positive end-plates compared with AChR antibody-positive end-plates, and C3 was detected in only two of eight MuSK Ab-positive patients. MuSK antibodies do not appear to cause substantial AChR loss, complement deposition, or morphological damage. Effects on MuSK function need to be explored.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Autoantibodies / immunology*
  • Child
  • Child, Preschool
  • Complement Activation
  • Complement C3 / immunology
  • Female
  • Humans
  • Male
  • Microscopy, Electron, Transmission
  • Middle Aged
  • Motor Endplate / immunology
  • Motor Endplate / ultrastructure
  • Muscle, Skeletal / immunology
  • Muscle, Skeletal / pathology
  • Muscle, Skeletal / ultrastructure
  • Myasthenia Gravis / immunology*
  • Myasthenia Gravis / pathology
  • Receptor Protein-Tyrosine Kinases / immunology*
  • Receptors, Cholinergic / immunology*

Substances

  • Autoantibodies
  • Complement C3
  • Receptors, Cholinergic
  • MUSK protein, human
  • Receptor Protein-Tyrosine Kinases