title: Acetylcholine receptors loss and postsynaptic damage in MuSK antibody-positive myasthenia gravis.
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.
authors.affiliation: The First Department of Internal Medicine, Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Shiraishi
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Motomura
authors.forename: Toshiro
authors.initials: T
authors.lastname: Yoshimura
authors.forename: Takayasu
authors.initials: T
authors.lastname: Fukudome
authors.forename: Taku
authors.initials: T
authors.lastname: Fukuda
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nakao
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Tsujihata
authors.forename: Angela
authors.initials: A
authors.lastname: Vincent
authors.forename: Katsumi
authors.initials: K
authors.lastname: Eguchi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D003167:Complement Activation; D003176:Complement C3 / Q000276:immunology; D005260:Female; D006801:Humans; D008297:Male; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D009045:Motor Endplate / Q000276:immunology / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000276:immunology / Q000473:pathology / Q000648:ultrastructure; D009157:Myasthenia Gravis / Q000276:immunology* / Q000473:pathology; D020794:Receptor Protein-Tyrosine Kinases / Q000276:immunology*; D011950:Receptors, Cholinergic / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D003176:Complement C3; D011950:Receptors, Cholinergic; C095714:MUSK protein, human; D020794:Receptor Protein-Tyrosine Kinases