Regarding cytokines, the IL-6 level was similar, while IL-10 (median concentration: 499.6 pg/mL vs. 19.9 pg/mL, P < 0.001) and IFN-γ (median concentration: 629.0 pg/mL vs. 8.2 pg/mL, P < 0.001) levels were significantly higher in patients with EBV-HLH (Fig. 1). This evidence concerns the gene IFNG and hemophagocytic syndrome.