CXCL9 levels in AOSD patients (595.6 ± 790.8 pg/mL) were higher than those in RA patients (64.7 ± 51.1 pg/mL; p < 0.001) and HCs (46.2 ± 31.7 pg/mL; p < 0.001). Here, CXCL9 is linked to rheumatoid arthritis.