A comparison of IFN-γ, CXCL9, CXCL10, and CXCL11 levels showed that serum levels of CXC chemokines were significantly higher among AOSD patients with RHS than in patients without RHS (CXCL9: 1622.5 ± 867.6 vs. 478.2 ± 703.1 pg/mL, p = 0.004; CXCL10: 494.0 ± 119.6 vs. 199.2 ± 170.6 pg/mL, p = 0.003; CXCL11: 513.0 ± 412.1 vs. 177.5 ± 140.9 pg/mL, p = 0.017). This evidence concerns the gene CXCL9 and adult-onset Still disease.