1 Larroche C, Mouthon L. Pathogenesis of hemophagocytic syndrome (HPS). Autoimmun Rev 2004;3:69–75. 2 Ravelli A. Macrophage activation syndrome. Curr Opin Rheumatol 2002;14: 548–52. 3 Hibi S, Ikushima S, Fujiwara F et al. Serum and urine beta-2-microglobulin in hemophagocytic syndrome. Cancer 1995;75:1700–5. 4 Wellwood JM, Ellis BG, Price RG, Hammond K, Thompson AE, Jones NF. Urinary N-acetylbe...