Patients with HLH have high levels of various proinflammatory cytokines such as interferon-γ (IFN-γ), interleukin (IL)-6, IL-8, IL-10, IL-12, IL-18, tumor necrosis factor-α (TNF-α), and macrophage inflammatory protein-1α (MIP-1α)3. The gene discussed is IFNG; the disease is hemophagocytic syndrome.