title: Synovial fibroblast hyperplasia in rheumatoid arthritis: clinicopathologic correlations and partial reversal by anti-tumor necrosis factor therapy.
abstract: OBJECTIVE
  Synovial fibroblast (SF) hyperplasia contributes to the pathogenesis of rheumatoid arthritis (RA), but quantitative information on this process is scarce. This study was undertaken to evaluate the fibroblast-specific marker Hsp47 as a quantitative marker for SFs and to analyze its clinicopathologic correlates and evolution after anti-tumor necrosis factor α (anti-TNFα) therapy.
  
  
  METHODS
  Synovial biopsy samples were obtained from 48 patients with RA and 20 controls who were healthy or had osteoarthritis (OA). Twenty-five RA patients who had active disease at the time of biopsy underwent a second biopsy after anti-TNFα therapy. Immunolabeling for Hsp47, inflammatory cells, and vascular cell markers was performed. Hsp47-positive lining and sublining fractional areas were quantified, and their correlation with clinicopathologic variables was analyzed.
  
  
  RESULTS
  In normal and diseased synovial tissue, Hsp47 was specifically and uniformly expressed by lining, sublining, and perivascular fibroblasts. Lining SF area was significantly increased in both RA and late OA tissue compared to normal tissue. Sublining SF area was increased in RA tissue but not in late OA tissue compared to normal tissue. Lining SF area was positively correlated with macrophage density, Disease Activity Score in 28 joints, and RA disease duration. In contrast, sublining SF area was negatively correlated with RA disease duration and activity. A significant reduction in lining SF area but not sublining SF area was observed after anti-TNFα therapy.
  
  
  CONCLUSIONS
  Our findings indicate that Hsp47 is a reliable marker for quantifying SFs in human synovial tissue. Our data suggest that lining and sublining SFs undergo different dynamics during the course of the disease. Lining SF expansion parallels the activity and temporal progression of RA and can be partially reversed by anti-TNFα therapy.
authors.affiliation: Servicio de Reumatología, Hospital 12 de Octubre, Madrid, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Izquierdo
authors.forename: Juan D
authors.initials: JD
authors.lastname: Cañete
authors.forename: Raquel
authors.initials: R
authors.lastname: Celis
authors.forename: Manuel J
authors.initials: MJ
authors.lastname: Del Rey
authors.forename: Alicia
authors.initials: A
authors.lastname: Usategui
authors.forename: Sara
authors.initials: S
authors.lastname: Marsal
authors.forename: Raimon
authors.initials: R
authors.lastname: Sanmartí
authors.forename: Gabriel
authors.initials: G
authors.lastname: Criado
authors.forename: José L
authors.initials: JL
authors.lastname: Pablos
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000494:pharmacology / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000473:pathology*; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000473:pathology*; D006801:Humans; D006965:Hyperplasia / Q000188:drug therapy / Q000473:pathology; D007719:Knee Joint / Q000187:drug effects / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000188:drug therapy / Q000473:pathology; D013583:Synovial Membrane / Q000187:drug effects / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D000911:Antibodies, Monoclonal; D014409:Tumor Necrosis Factor-alpha