Hemophagocytic syndrome is an autoimmune disease characterized by the activation and proliferation of macrophages, T CD8+ lymphocytes and NK cells in the bone marrow and in other endothelial reticular systems (172), leading to the phagocytosis of erythrocytes, leukocytes, platelets, and their precursors and to the exacerbated production of several inflammatory cytokines, including IL-1β, IL-2, IL-6, TNF-α, and IFN-γ (173). The gene discussed is IL2; the disease is hemophagocytic syndrome.