IL18 and systemic-onset juvenile idiopathic arthritis: High levels of serum IL-18 levels were reported in patients with systemic juvenile idiopathic arthritis (s-JIA) (16–25) and its adult homolog adult Still’s disease (AOSD) (26–30), as well as various other inflammatory diseases including systemic lupus erythematosus (50) and Crohn’s disease (51).