Table 1.

HLH-2004 diagnostic criteria

Criteria	Patient meeting criterion
Fever (≥38.5°C)	No
Splenomegaly	No
Cytopenias (≥2)	Yes: hemoglobin 8.4 g/dL, platelets 17 K/μL
Hypertriglyceridemia	Yes: 521 mg/dL
Hemophagocytosis	Yes: in bone marrow
Low or absent NK cell activity	–
Ferritin >500 ng/mL	Yes: >7500
Elevated soluble CD25	Yes: 36,628 U/mL
Elevated CXCL9	–