title: Expression of B7-homolog 1 in Polymyositis.
abstract: OBJECTIVE
  Costimulatory molecules are increasingly recognized as crucial for stimulation and/ or inhibition of immune responses. The present study was undertaken to examine the expression and functional relevance of B7-homolog 1 (B7-H1) attributed significant immunoregulatory functions in polymyositis in vivo.
  
  
  METHODS
  43 muscle biopsy specimens obtained from patients with polymyositis, 26 cases with limb girdle muscular dystrophies (LGMD) 2B and 21 normal muscle samples were analyzed by immunohistochemistry for B7-H1 expression. The clinical and histopathologic data were analyzed.
  
  
  RESULTS
  B7-H1 was not detectable on normal muscle fibers and rarely detectable from patients with LGMD-2B. In contrast, its expression was markedly increased on muscle fibers from patients with polymyositis, even after short-term immunosuppressive treatment. Positive staining mainly localized at the surface of the muscle tissue, rarely in the cytoplasm, focused in areas where inflammatory cells lay in close apposition to damaged, necrotic or degenerative muscle fibers. The expression of B7-H1 was correlated to the degrees of muscular necrosis and clinical muscular strength.
  
  
  CONCLUSIONS
  Our results demonstrate that human muscle cells express B7-H1 in polymyositis. The muscle-related expression of B7-H1 may be helpful in the diagnosis of polymyositis and might be an indicator of prognosis of polymyositis.
authors.affiliation: Department of Neurology, The First Hospital of Soochow University, No.188 Shizi Street, Suzhou, China.
authors.forename: Duan
authors.initials: D
authors.lastname: Xiaoyu
authors.forename: Wang
authors.initials: W
authors.lastname: Yunxia
authors.forename: Fang
authors.initials: F
authors.lastname: Qi
authors.forename: Wang
authors.initials: W
authors.lastname: Dapeng
authors.forename: Cai
authors.initials: C
authors.lastname: Xiuying
authors.forename: Jiang
authors.initials: J
authors.lastname: Jianhua
authors.forename: Wang
authors.initials: W
authors.lastname: Hongxia
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D060890:B7-H1 Antigen / Q000032:analysis / Q000378:metabolism*; D016022:Case-Control Studies; D002648:Child; D003402:Creatine Kinase / Q000097:blood; D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D049288:Muscular Dystrophies, Limb-Girdle / Q000378:metabolism* / Q000473:pathology; D017285:Polymyositis / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D012016:Reference Values; D055815:Young Adult
chemical_list: D060890:B7-H1 Antigen; C423236:CD274 protein, human; D003402:Creatine Kinase