CXCR6-CXCL16 interaction in the pathogenesis of Juvenile Idiopathic Arthritis

In order to evaluate the role of CXCR6/CXCL16 in driving lymphocyte migration into inflamed joints of children with oligoarticular Juvenile Idiopathic Arthritis (JIA) we analysed CXCR6 expression and functional capability in lymphocytes from synovial fluid (SF) by flow cytometry, by real-time polymerase chain reaction (RT-PCR) and migration assays. Furthermore, CXCR6 and CXCL16 expression in synovial tissue (ST) was analysed by immunohistochemistry.T cells isolated from SF of patients with JIA expressed CXCR6 which was functionally active as shown by chemotactic assays. The same cells expressed CXCR3 and it exerted a migratory activity in response to CXCL10. CXCL16 and CXCR6 were intensively expressed on the synovium cells, respectively on macrophages, synoviocytes and endothelial cells and on lymphocytes, synoviocytes and endothelial cells. Taken together, these data suggest that CXCR6 and CXCR3 act coordinately with respective ligands and are involved in the pathophysiology of JIA-associated inflammatory processes.