title: Localization of tumor necrosis factor receptors in the synovial tissue and cartilage-pannus junction in patients with rheumatoid arthritis. Implications for local actions of tumor necrosis factor alpha.
abstract: OBJECTIVE
  We have previously described the location of tumor necrosis factor alpha (TNF alpha)-producing cells in synovial tissue and cartilage-pannus junction in rheumatoid arthritis (RA). To further understand the local actions of TNF alpha, we investigated the expression of TNF receptors (TNF-R) on cells in the same compartments in patients with RA.
  
  
  METHODS
  The expression of both p55 TNF-R and p75 TNF-R was determined using alkaline phosphatase-conjugated mouse anti-alkaline phosphatase (APAAP) and double immunofluorescence staining techniques with monoclonal antibodies.
  
  
  RESULTS
  In RA synovial membrane, both p55 TNF-R and p75 TNF-R were detectable in up to 90% of the cells in the lining layer, and were demonstrated on cells in deeper layers of the membrane, including vascular endothelial cells. Cells in lymphoid aggregates expressed both TNF-R, but with a predominant expression of p75 receptor. At the cartilage-pannus junction, the majority of pannus cells, especially those invading cartilage, expressed both the p55 and the p75 TNF-R. Sequential section and double immunofluorescence staining showed that the TNF-R-expressing cells were in the vicinity of TNF alpha-containing cells, and some TNF alpha-containing cells also expressed TNF-R. TNF-R-expressing cells were also detected in osteoarthritic and normal synovial tissue, but in smaller numbers and at a lower intensity.
  
  
  CONCLUSIONS
  These results provide histologic evidence that both p55 TNF-R and p75 TNF-R are expressed by a variety of cell types in RA synovial tissue, reflecting the fact that a wide range of cells are potential targets for TNF alpha in this tissue. This study further supports the hypothesis that TNF alpha plays a major role in the pathogenesis of RA.
authors.affiliation: Mathilda and Terence Kennedy Institute of Rheumatology, Bute Gardens and Sunley Research Centre, London, England, UK.
authors.forename: B W
authors.initials: BW
authors.lastname: Deleuran
authors.forename: C Q
authors.initials: CQ
authors.lastname: Chu
authors.forename: M
authors.initials: M
authors.lastname: Field
authors.forename: F M
authors.initials: FM
authors.lastname: Brennan
authors.forename: T
authors.initials: T
authors.lastname: Mitchell
authors.forename: M
authors.initials: M
authors.lastname: Feldmann
authors.forename: R N
authors.initials: RN
authors.lastname: Maini
mesh_terms: D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D002358:Cartilage, Articular / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007124:Immunoenzyme Techniques; D008970:Molecular Weight; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor; D013583:Synovial Membrane / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
chemical_list: D011956:Receptors, Cell Surface; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha