Markers of macrophage activation, e.g. macrophage migration inhibitory factor (MIF) (57, 58), a proinflammatory cytokine with the ability of upregulating the expression of proinflammatory mediators, and macrophage-colony stimulating factor (M-CSF) (59) were reported to be increased in the serum of AOSD patients and correlated with disease activity. The gene discussed is CSF1; the disease is adult-onset Still disease.