Rheumatoid arthritis and the alpha-chemokine IP-10.

Interferon(IFN)-gamma-induced protein 10 (IP-10) and its receptor, CXCR3, appear to contribute to the pathogenesis of rheumatoid arthritis (RA). IP-10 has been detected in sera, synovial fluid (SF), and synovial tissue in RA patients. IP-10 is mainly expressed by infiltrating macrophage-like cells and fibroblast-like synoviocytes in RA synovium. The elevated expression of CXCR3 on T cells from SF has been associated with high levels of IFN-gamma, which suggest a preferential Th1 phenotype. A human phase II clinical trial using an anti-IP-10 monoclonal antibody (MDX-1100) for RA patients who had an inadequate response to methotrexate treatment has shown that blocking IP-10 significantly increased response rate compared to the placebo group, suggesting a possible therapeutic use in humans.