Multiple recent publications tried to establish the role of pro-inflammatory cytokines, such as interleukin-18 (IL-18), interferon-γ (IFN-γ), and IL-1β on MAS pathogenesis and proposed the detection of these cytokines as biomarkers to classify MAS as well as cytokine antagonists to treat the disease (8–11). This evidence concerns the gene IL1B and macrophage activation syndrome.