Although previous studies have identified several serum protein markers for AOSD, such as ferritin, inflammatory cytokines (IL-1β and IL-18), anti-inflammatory cytokines (IL-10 and IL-37), and chemokines (CXCL9/10/11) (6, 7, 20, 23), identifying urinary markers will furnish a more non-invasive method for clinical diagnosis. Here, CXCL9 is linked to adult-onset Still disease.