title: Prion protein is abnormally accumulated in inclusion-body myositis.
abstract: In muscle biopsies of 8 sporadic inclusion-body myositis (S-IBM) and 4 hereditary inclusion-body myopathy (H-IBM) patients, vacuolated muscle fibers contained within their vacuoles strongly immunoreactive inclusions with 2 polyclonal and 1 monoclonal antibodies against prion protein (PrP). By light-microscopy, PrP deposits co-localized with beta-amyloid protein (A beta) and ubiquitin (Ub). By immuno-electronmicroscopy, both PrP and A beta were present on amorphous material and on 6-10 nm amyloid-like fibrils; and PrP and Ub co-localized on cytoplasmic twisted tubulofilaments (TTFs) and on amorphous material. Our study provides the first demonstration of abnormally accumulated PrP in pathological tissue other than brain, and it suggests that PrP may play a role in the pathogenesis of IBM.
authors.affiliation: Department of Neurology, University of Southern California School of Medicine, Los Angeles 90017.
authors.forename: V
authors.initials: V
authors.lastname: Askanas
authors.forename: M
authors.initials: M
authors.lastname: Bilak
authors.forename: W K
authors.initials: WK
authors.lastname: Engel
authors.forename: R B
authors.initials: RB
authors.lastname: Alvarez
authors.forename: F
authors.initials: F
authors.lastname: Tomé
authors.forename: A
authors.initials: A
authors.lastname: Leclerc
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D006801:Humans; D007150:Immunohistochemistry; D002479:Inclusion Bodies / Q000473:pathology* / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D009132:Muscles / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D009220:Myositis / Q000378:metabolism / Q000473:pathology*; D011328:Prions / Q000032:analysis* / Q000378:metabolism; D014617:Vacuoles / Q000473:pathology / Q000648:ultrastructure
chemical_list: D011328:Prions