title: Altered expression of costimulatory molecules in patients with polymyositis.
abstract: OBJECTIVE
  : The objective of this study was to characterize the involvement of costimulatory molecules in patients with polymyositis (PM).
  
  
  METHODS
  : A multiparameter flow cytometry analysis was used to identify peripheral blood mononuclear cell (PBMNC) subsets expressing CD8, CD4, and CD28 in 14 patients with PM, 10 patients with Duchenne muscular dystrophy (DMD), and 10 healthy controls. Patients with PM were divided into the following 2 groups: patients with untreated active PM and patients with posttreated inactive PM.
  
  
  RESULTS
  : The percentage of CD8CD28/CD8 T cells and the absolute number of CD8CD28 double-positive T cells was significantly lower in the 9 patients with untreated active PM than in the 5 patients with posttreated inactive PM, the 10 patients with DMD, and the 10 healthy controls.
  
  
  CONCLUSIONS
  : Our results show that the CD28 pathway plays a role in PM and that CD8CD28 subsets of PBMNC may represent a useful biomarker of patients with PM.
authors.affiliation: From the Department of Neurology, Nara Medical University, Nara, Japan.
authors.forename: Miwa
authors.initials: M
authors.lastname: Takamure
authors.forename: Ken-Ya
authors.initials: KY
authors.lastname: Murata
authors.forename: Kazuma
authors.initials: K
authors.lastname: Sugie
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ueno