title: Receptor activator NF-kappaB ligand (RANKL) expression in synovial tissue from patients with rheumatoid arthritis, spondyloarthropathy, osteoarthritis, and from normal patients: semiquantitative and quantitative analysis.
abstract: OBJECTIVE
  To compare receptor activator of NF-kappaB ligand (RANKL) production in the synovial tissue from patients with active rheumatoid arthritis (RA), inactive RA, spondyloarthropathies (SpA), osteoarthritis, and from normal subjects. In addition, to establish the cell lineages expressing RANKL in these tissues.
  
  
  METHODS
  Immunohistological analysis of frozen synovial tissue biopsy specimens was performed using a monoclonal antibody (mAb) to detect RANKL. Sections were evaluated by computer assisted image analysis and semiquantitative analysis to compare RANKL expression between groups. Dual and sequential labelling with mAb RANKL and cell lineage specific monoclonal antibodies were used to determine the types of cells expressing RANKL.
  
  
  RESULTS
  Higher levels of RANKL were expressed in tissues from patients with active RA and SpA than in tissues from patients with inactive RA, osteoarthritis, and from normal subjects. RANKL protein was associated with CD3 antigen-positive lymphocytes and some macrophages. RANKL was predominantly associated with activated, memory T cells (CD45Ro positive cells) in patients with active RA and spondyloarthropathy (SpA).
  
  
  CONCLUSIONS
  The highest levels of RANKL were detected in patients with RA with active synovitis and in some patients with SpA. An increase in RANKL in the inflamed joint of patients with RA, produced by infiltrating activated T cells and macrophages, is likely to be an important cause of joint erosions in RA.
authors.affiliation: Department of Pathology, University of Adelaide, Adelaide, South Australia.
authors.forename: T N
authors.initials: TN
authors.lastname: Crotti
authors.forename: M D
authors.initials: MD
authors.lastname: Smith
authors.forename: H
authors.initials: H
authors.lastname: Weedon
authors.forename: M J
authors.initials: MJ
authors.lastname: Ahern
authors.forename: D M
authors.initials: DM
authors.lastname: Findlay
authors.forename: M
authors.initials: M
authors.lastname: Kraan
authors.forename: P P
authors.initials: PP
authors.lastname: Tak
authors.forename: D R
authors.initials: DR
authors.lastname: Haynes
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D017252:CD3 Complex / Q000032:analysis; D005260:Female; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D007124:Immunoenzyme Techniques; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008214:Lymphocytes / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism*; D053244:Osteoprotegerin; D018160:Receptors, Cytoplasmic and Nuclear / Q000032:analysis*; D018124:Receptors, Tumor Necrosis Factor / Q000032:analysis*; D025242:Spondylarthropathies / Q000378:metabolism*; D013582:Synovial Fluid / Q000378:metabolism*
chemical_list: D017252:CD3 Complex; D006023:Glycoproteins; D053244:Osteoprotegerin; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C506030:TNFRSF11B protein, human