IL18 and macrophage activation syndrome: Indeed, the different temporal dynamics of IL‐18, ferritin, CXCL10, and galectin‐9 observed in our cohort might suggest IL‐18 and ferritin as early indicators of escalating inflammation and risk for developing MAS, whereas the later increase in CXCL10 and galectin‐9 levels, both reflecting the activation of IFN signaling,16, 43, 44, 45 may be interpreted as the transition to overt MAS.