title: Elevated levels of T helper 17 cells are associated with disease activity in patients with rheumatoid arthritis.
abstract: BACKGROUND
  Interleukin-17 (IL-17)-producing T helper (Th) 17 cells are considered as a new subset of cells critical to the development of rheumatoid arthritis (RA). We aimed to investigate the distribution of Th1 and Th17 cells and their association with disease activity, and determine the Th17-related cytokine levels in the peripheral blood of RA patients.
  
  
  METHODS
  Peripheral blood mononuclear cells from 55 RA and 20 osteoarthritis (OA) patients were stimulated with mitogen, and the distributions of CD4(+)Interferon (INF)(+)IL-17(-) (Th1 cells) and CD4(+)INF-IL-17(+) (Th17 cells) were examined by flow cytometry. Serum levels of IL-6, IL-17, IL-21, IL-23, and tumor necrosis factor (TNF)-α were measured by ELISA. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were recorded. The 28-joint disease activity score (DAS28) was also assessed.
  
  
  RESULTS
  The median percentage of Th17 cells was higher in RA patients than in OA patients (P=0.04), and in active than in inactive RA (P=0.03), whereas that of Th1 cells was similar in both groups. Similarly, the levels of IL-17, IL-21, and IL-23 were detected in a significantly higher proportion of RA patients than OA patients and the frequencies of detectable IL-6, IL-17, and IL-21 were higher in active RA than in inactive RA group. The percentage of Th17 cells positively correlated with the DAS28, ESR, and CRP levels.
  
  
  CONCLUSIONS
  These observations suggest that Th17 cells and Th17-related cytokines play an important role in RA pathogenesis and that the level of Th17 cells in peripheral blood is associated with disease activity in RA.
authors.affiliation: Department of Laboratory Medicine, Chungnam National University College of Medicine, Daejeon, Korea.
authors.forename: Jimyung
authors.initials: J
authors.lastname: Kim
authors.forename: Seongwook
authors.initials: S
authors.lastname: Kang
authors.forename: Jinhyun
authors.initials: J
authors.lastname: Kim
authors.forename: Gyechul
authors.initials: G
authors.lastname: Kwon
authors.forename: Sunhoe
authors.initials: S
authors.lastname: Koo
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000378:metabolism / Q000473:pathology*; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis; D016207:Cytokines / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000097:blood / Q000378:metabolism / Q000473:pathology; D012720:Severity of Illness Index; D018417:Th1 Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D058504:Th17 Cells / Q000166:cytology* / Q000276:immunology / Q000378:metabolism
chemical_list: D016207:Cytokines; D002097:C-Reactive Protein
keywords: Cytokines; Rheumatoid arthritis; T helper 1 cell; T helper 17 cell