Clonotypic archetype of the T cell repertoire in peripheral blood and synovial fluid of patients with juvenile idiopathic arthritis?

Introduction: Juvenile Idiopathic Arthritis (JIA) is characterized by chronic inflammation, synovial cell proliferation and progressive joint damage. T cells have been demonstrated to play a key role both in induction and in maintenance of chronic inflammation in Juvenile Idiopathic Arthritis (JIA). Previous studies have demonstrated discrepant results regarding the significance of T cell clonality. Objective and Methods: To investigate the T cell repertoire of the T cell receptor (TCR) in paired samples from peripheral blood and synovial fluid (SF) of patients with JIA. Oligoclonality was analysed on the base of the TCR β-chain variability. Matched pairs of peripheral blood and synovial fluid from eleven patients with JIA were studied by multicolor flow cytometry using a panel of TCR Vβ and CD4 or CD8 specific monoclonal antibodies. All patients had active disease. Ten presented with persistent oligoarthritis and one with enthesitis associated arthritis according to the ILAR criteria of the ILAR. Results: Patients demonstrated a significant predominance of T cells (CD4 + ) bearing TCRs of the Vβ1, 2, 5.1, 13.6 and 17 in the periphheral blood and of the Vβ 5.3, 12 and 16 in the synovial fluid. In CD8 + cells the TCR expresses Vβ8, 11, again 13.1, 17 and 23 in the peripheral blood whereas again Vβ 5.3 and 12 and 13.2 are more expressed in the intraarticular cells. The CD4/CD8 ratio in the knee is in normal range (0,91–3,61). Double positive T cells present significantly 5.2, 5.3 and 13.1 in periperal blood mononuclear cells and Vβ1, 2, 3, 4, 5.1, 12, 13.6 and 21.3 expansions were most commonly found in the in the synovial fluid. Conclusions: Oligoclonal expression of intrarticular T cells in JIA affects several Vβ families with distinct patterns within CD4 + and CD8 + poitive cells.