IL1A and systemic-onset juvenile idiopathic arthritis: The demonstration of the prominent involvement of IL-1, together with the lack of HLA associations and autoantibodies and the strong implication of cells of the innate immune system, has led to the suggestion that sJIA is a distinct disease entity, with more similarities with autoinflammatory syndromes than with classic autoimmune diseases (Masters et al., 2009; Vastert et al., 2009; Mellins et al., 2011; Martini, 2012b).