Disbalance between IL-18 and IL-18BP has been described as pathogenic in autoinflammatory diseases such as adult-onset Still’s disease (AOSD) and its children counterpart, systemic juvenile idiopathic arthritis (sJIA), macrophage activation syndrome (MAS) (7), and NLRC4 gain-of-function inflammasomopathy (8, 9). Here, NLRC4 is linked to systemic-onset juvenile idiopathic arthritis.