IL18BP and macrophage activation syndrome: Increased IL-8, IL-18BP, and sCD163 levels were causally associated with MAS; increased IL-8, MIP-1 alpha, M-CSF, and sCD25/IL-2Ra levels were causally associated with increased MCP-1/CCL2 levels; and increased IL-18BP and sCD163 levels were causally associated with hyperferritinemia (Figs. 3 and 4).