Fire behind the fury: IL-18 and MAS

In this issue of Blood, Weiss et al and Girard-Guyonvarc'h et al demonstrate the ability of free plasma interleukin-18 (IL-18) to distinguish macrophage activation syndrome (MAS) from other inflammatory disorders. Furthermore, with several animal models, they demonstrate that IL-18 is not just a bio-marker but rather a driver of inflammation and potential therapeutic target in some patients with MAS.(1,2)