title: Characterization and regulation of CD69 expression on rheumatoid arthritis synovial fluid T cells.
abstract: OBJECTIVE
  To study CD69+ synovial fluid (SF) T cells and the mechanisms regulating CD69 expression in rheumatoid arthritis (RA).
  
  
  METHODS
  One or 2 color flow cytometry was used to determine CD69 and other surface markers. Cultures of SF T cells alone or mixed with autologous SF non-T cells were used for CD69 maintenance assays.
  
  
  RESULTS
  SF T cells were enriched in CD69+. These cells were mainly CD3+, CD8+ and CD25-. CD69 was maintained on SF T cells cultured with SF non-T cells but not when the former were cultured alone or in the presence of different supernatants from RA SF T and non-T cells cultures with sustained CD69 expression. Pretreatment of T and non-T cells with anti-CD18 monoclonal antibody inhibited CD69 expression, while paraformaldehyde-"fixed" non-T cells effectively maintained it.
  
  
  CONCLUSIONS
  SF T cells exhibit a phenotype with evidence of past and recent activation. Our studies demonstrate that most of the recently activated SF T cells are CD8+. We also found that continuous cell-to-cell interaction between T and non-T cells are responsible for the maintenance of this particular state of activation of SF T cells.
authors.affiliation: Service of Rheumatology, Hospital Universitario San Carlos, Madrid, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Fernández-Gutiérrez
authors.forename: C
authors.initials: C
authors.lastname: Hernández-García
authors.forename: A A
authors.initials: AA
authors.lastname: Bañares
authors.forename: J A
authors.initials: JA
authors.lastname: Jover
mesh_terms: D015703:Antigens, CD / Q000032:analysis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D001172:Arthritis, Rheumatoid / Q000276:immunology* / Q000473:pathology; D001773:Blood Cells / Q000276:immunology; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D037181:Lectins, C-Type; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D013582:Synovial Fluid / Q000166:cytology / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D013997:Time Factors; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D037181:Lectins, C-Type; D000099192:CD69 Antigens