Table 3.

Diagnostic guidelines for HLH used in the HLH-2004 trial.

The diagnosis of HLH can be established if one of either 1 or 2 below is fulfilled. 1. A molecular diagnosis consistent with HLH. 2. Diagnostic criteria for HLH fulfilled (at least 5 out of the 8 criteria below) 1) Fever ≥38.5°C 2) Splenomegaly 3) Cytopenia involving ≥2 cell lines

Hemoglobin <90 g/L (in infants <4 weeks: hemoglobin <100 g/L)

Platelets <100 × 109/L

Neutrophils <1.0 × 109/L

4) Hypertriglyceridemia (fasting, ≥265 mg/dL) or hypofibrinogenemia (≤1.5g/L) 5) Hemophagocytosis in bone marrow, spleen, or lymph nodes 6) Low or absent natural killer cell activity 7) Serum ferritin > 500μg/L 8) Elevated CD25 (soluble IL-2 receptor) levels (>2400 U/mL)