Considering that macrophages/monocytes of sHLH produce a mixture of cytokines, particularly TNF and various interleukins (i.e., IL-6, IL-1β and IL-18), which trigger a series of inflammatory pathways and ultimately produce a cytokine storm (23), with elevated sCD25 as an early marker of T-cell activation in HLH and closely associated with IFN-γ (24). This evidence concerns the gene IL6 and hemophagocytic syndrome.