CXCL10 and rheumatoid arthritis: As shown in Figure 1, CXCL10 concentrations were significantly increased in RA synovial fluid (mean ± standard error: 1,502.0 ± 87.1 pg/mL versus 267.3 ± 87.0 pg/mL; P < 0.01) and sera (363.9 ± 78.9 pg/mL versus 87.7 ± 10.8 pg/mL; P < 0.01) than in those of OA.