Immunoglobulin (Ig)G-4 related myositis - A new entity?

Neuromuscul Disord. 2019 Jan;29(1):70-74. doi: 10.1016/j.nmd.2018.11.009. Epub 2018 Nov 24.

Abstract

Immunoglobulin (Ig)G4-related disease is an uncommon systemic autoimmune disorder characterized by infiltration of IgG4+ plasma cells in different organs and elevated levels of IgG4 in peripheral blood. So far, only one case of myositis with abundant IgG4+ plasma cells has been reported and classified as 'polymyositis'. We present an unusual case of chronic inflammatory myopathy in a context of rheumatoid arthritis. Severe granulomatous myositis, featuring abundant IgG4+ plasma cells was identified in two skeletal muscle biopsies within a five-year-interval. We suggest this entity to be a new subtype of immunoglobulin G4-related disease: IgG4-related myositis, while there were no diagnostic criteria fulfilled for the known idiopathic inflammatory myopathies.

Keywords: Eosinophils; Granuloma; IgG4- related disease; Myositis.

Publication types

  • Case Reports

MeSH terms

  • Arthritis, Rheumatoid / complications
  • Arthritis, Rheumatoid / diagnosis
  • Arthritis, Rheumatoid / drug therapy
  • Arthritis, Rheumatoid / immunology
  • Female
  • Humans
  • Immunoglobulin G4-Related Disease / classification
  • Immunoglobulin G4-Related Disease / complications
  • Immunoglobulin G4-Related Disease / diagnosis*
  • Immunoglobulin G4-Related Disease / drug therapy
  • Middle Aged
  • Muscle, Skeletal / diagnostic imaging
  • Muscle, Skeletal / pathology
  • Myositis / classification
  • Myositis / diagnosis*
  • Myositis / drug therapy
  • Myositis / immunology*