title: Thymic myoid cells and germinal center formation in myasthenia gravis; possible roles in pathogenesis.
abstract: In early-onset myasthenia gravis (EOMG), the thymus usually shows medullary lymph node-type infiltrates, rearranged bands of hyperplastic epithelium and focal fenestrations in the intervening laminin borders. This resemblance to autoimmune target organs may reflect autoantigen expression by rare thymic myoid cells, long ago implicated circumstantially as agents provocateurs. In this quantitative study, they were frequently seen at the laminin fenestrations; if so, germinal centers (GC) were significantly commoner nearby, our most EOMG-specific finding (not seen in a distinct MG patient subset). As autoantibodies became detectable, myoid cell involvement apparently progressed. Our unifying hypothesis--that an early autoantibody attack on myoid cells provokes local GC formation--helps to resolve many puzzles.
authors.affiliation: Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Roxanis
authors.forename: Kingsley
authors.initials: K
authors.lastname: Micklem
authors.forename: John
authors.initials: J
authors.lastname: McConville
authors.forename: John
authors.initials: J
authors.lastname: Newsom-Davis
authors.forename: Nick
authors.initials: N
authors.lastname: Willcox
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000911:Antibodies, Monoclonal; D017951:Antigen Presentation / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology; D018858:Germinal Center / Q000473:pathology*; D006801:Humans; D007797:Laminin / Q000032:analysis; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000209:etiology / Q000276:immunology / Q000473:pathology; D016176:T-Lymphocyte Subsets / Q000276:immunology; D013950:Thymus Gland / Q000737:chemistry / Q000473:pathology*
chemical_list: D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D007797:Laminin