Studies have shown that immune defects in genes affecting regulation of granule-dependent lymphocyte activity as well as intracellular granule trafficking, mutations in T cell functioning (CD27), and cytokine production, that is, interferon (IFN)-gamma and interleukin (IL)-6, by malignant cells play a key role in HLH evolution [5, 8]. This evidence concerns the gene CD27 and hemophagocytic syndrome.