Of note, IL-18/IL-18BP imbalance seems to be correlated with the risk of MAS, as seen in sJIA-MAS and NLRC4-MAS (16, 34); however, several subtypes of PAID exhibiting IL-18/IL-18BP imbalance are less likely to be associated with high incidence of MAS (59). This evidence concerns the gene IL18 and macrophage activation syndrome.