title: Increased expression of CD154 (CD40L) on stimulated T-cells from patients with psoriatic arthritis.
abstract: OBJECTIVE
  CD40L is a costimulatory molecule and an early activation marker of T-lymphocytes. Based on the hypothesis that activated T-cells may play a role in the pathogenesis of psoriatic arthritis (PsA), we evaluated the level of CD40L expression on T-cells from patients with PsA.
  
  
  METHODS
  We analysed 12 patients with PsA, six patients with rheumatoid arthritis (RA) and four healthy volunteers. T-cell surface expression of CD40L was evaluated using two-colour flow cytometry in (i) the resting state and (ii) following stimulation with phorbol myristate acetate/ionomycin, with or without ciclosporin (CsA)-mediated inhibition.
  
  
  RESULTS
  Expression of CD40L was significantly increased on activated T-cells from patients with PsA, particularly those with active disease, when compared with normal individuals and patients with RA (mean percentages of CD3+ CD40L+ cells: 23.74, 11.59 and 9.57% for patients with active PsA, patients with RA and healthy volunteers, respectively). CsA-mediated inhibition of CD40L induction was equally effective in all study groups.
  
  
  CONCLUSIONS
  CD40L is overexpressed on T-cells from patients with active PsA. This may indicate a role for CD40L in PsA pathogenesis. Larger-scale studies are warranted to address these issues.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Patras University Hospital, 26504 Rion, Patras Greece.
authors.forename: D
authors.initials: D
authors.lastname: Daoussis
authors.forename: I
authors.initials: I
authors.lastname: Antonopoulos
authors.forename: A P
authors.initials: AP
authors.lastname: Andonopoulos
authors.forename: S-N C
authors.initials: SN
authors.lastname: Liossis
mesh_terms: D000328:Adult; D000368:Aged; D015535:Arthritis, Psoriatic / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000276:immunology; D023201:CD40 Ligand / Q000096:biosynthesis / Q000097:blood*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D016572:Cyclosporine / Q000494:pharmacology; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*
chemical_list: D007166:Immunosuppressive Agents; D023201:CD40 Ligand; D016572:Cyclosporine