title: Elevated expression of CD80 (B7/BB1) and other accessory molecules on synovial fluid mononuclear cell subsets in rheumatoid arthritis.
abstract: OBJECTIVE
  To assess the expression of important accessory molecules such as CD80 (B7/BB1) and CD54 (intercellular adhesion molecule 1) on potential antigen-presenting cells (APC) in the synovial fluid (SF) of patients with rheumatoid arthritis (RA).
  
  
  METHODS
  The level of expression of various accessory molecules on T cells, monocytes, and CD5+ or CD5- B cells from RA SF was compared, by multiparameter flow cytometric analysis, with the expression on peripheral blood (PB) mononuclear cells from the same patients and from normal controls. The functional significance of increased expression of these accessory molecules was assessed by the ability of the different cell populations to stimulate T cells in the mixed lymphocyte reaction.
  
  
  RESULTS
  Monocytes, T cells, and B cells isolated from the SF of inflamed joints of patients with RA expressed significantly higher levels of CD80 and CD54 than those from the PB of RA patients or normal controls. CD11b and CD11c expression also were increased on SF B cells, while SF monocytes exhibited enhanced levels of CD40. Further, we found that the elevated CD80 and CD54 levels in RA SF cells may enhance the capacity of these cells to act as stimulatory APC.
  
  
  CONCLUSIONS
  This is the first demonstration that specific cell subsets constitutively express increased levels of CD80 at a site of autoimmune pathology, which could potentially contribute to the initiation or maintenance of autoimmune disease.
authors.affiliation: University of California, San Diego 92093-0663.
authors.forename: E A
authors.initials: EA
authors.lastname: Ranheim
authors.forename: T J
authors.initials: TJ
authors.lastname: Kipps
mesh_terms: D000938:Antigen-Presenting Cells / Q000276:immunology; D015703:Antigens, CD / Q000378:metabolism; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D018122:B7-1 Antigen / Q000378:metabolism*; D051940:B7-2 Antigen; D018845:CD11 Antigens / Q000378:metabolism; D019013:CD40 Antigens; D018956:CD5 Antigens; D005434:Flow Cytometry; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D016131:Lymphocyte Subsets / Q000276:immunology; D008562:Membrane Glycoproteins; D009000:Monocytes / Q000276:immunology; D013582:Synovial Fluid / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018845:CD11 Antigens; D019013:CD40 Antigens; D018956:CD5 Antigens; C497964:CD86 protein, human; D008562:Membrane Glycoproteins; D018799:Intercellular Adhesion Molecule-1