The 8 criteria for HLH diagnosis include: 1. Fever 2. Splenomegaly 3. Cytopenias affecting at least two of three lineages in the peripheral blood 4. Hypertriglyceridemia and/or hypofibrinogenemia 5. Hemophagocytosis in bone marrow, spleen, or lymph nodes, without evidence of malignancy 6. Low or absent natural killer (NK) cell activity 7. Hyperferritinemia 8. Elevated soluble CD25 (sIL-2R)
