More recently, IL-1 activity has been linked to the pathogenesis of Still's disease as well as other systemic inflammatory diseases characterized in part by recurrent fevers, leucocytosis, anemia, and elevated acute-phase proteins, because rapid and sustained resolution of systemic and local inflammation is observed upon specific blockade of IL-1 receptors (IL-1R) [11]. Here, IL1R1 is linked to systemic-onset juvenile idiopathic arthritis.