title: Polymyositis as a manifestation of chronic graft-versus-host disease.
abstract: OBJECTIVE
  Chronic graft-versus-host disease (GVHD) after haematopoietic stem cell transplantation (HSCT) has similarities to some idiopathic autoimmune diseases, including polymyositis. To investigate the relationship between chronic GVHD and idiopathic myositis we conducted a detailed analysis of all cases of myositis occurring in a large series of HSCT patients.
  
  
  METHODS
  We conducted a retrospective chart review of all cases of myositis that developed in 7161 patients who underwent HSCT at the Fred Hutchinson Cancer Research Center between 1969 and 1999.
  
  
  RESULTS
  Among 1859 individuals who developed chronic GVHD, 12 developed myositis. No patients developed myositis without chronic GVHD. Myositis was first identified between 7 and 55 months after transplantation. In histopathology, electromyography, laboratory values and response to immunosuppressive therapy, the cases resembled idiopathic polymyositis. Autoantibodies were found in eight cases.
  
  
  CONCLUSIONS
  Myositis in the chronic GVHD population occurred with an incidence higher than expected by chance, suggesting that muscle may be a target tissue for chronic GVHD. Recent studies have implicated allogeneic cells persisting after maternal-fetal cell transfer in selected autoimmune diseases, including myositis. This report lends support to the possibility that both idiopathic myositis and chronic GVHD-related myositis could involve allo-autoimmune responses.
authors.affiliation: Immunogenetics D2-100, Fred Hutchinson Cancer Research Center, University of Washington, 1100 Fairview Avenue NE, Seattle, WA 98109, USA. astevens@fhcrc.org
authors.forename: A M
authors.initials: AM
authors.lastname: Stevens
authors.forename: K M
authors.initials: KM
authors.lastname: Sullivan
authors.forename: J L
authors.initials: JL
authors.lastname: Nelson
mesh_terms: D000328:Adult; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D005260:Female; D005500:Follow-Up Studies; D006086:Graft vs Host Disease / Q000150:complications* / Q000276:immunology; D018380:Hematopoietic Stem Cell Transplantation; D006650:Histocompatibility Testing; D006801:Humans; D008297:Male; D008875:Middle Aged; D017285:Polymyositis / Q000175:diagnosis / Q000209:etiology* / Q000276:immunology; D012189:Retrospective Studies; D014184:Transplantation, Homologous