In the patients, the mean number of the HLH-2004 criteria was 6 (range, 5-6), the mean body temperature was 38.5°C (range 38.5°C-40°C), eight patients (88%) had spleen enlargement, the mean hemoglobin count was 7.7 g/L (range, 7.3-8.6 g/L), the mean platelet count was 27×109/L (range, 26-29), the mean WBC count was 4.4×109/L (range, 3.3-7.8), the mean triglyceridemia level was 2.6 mmol/L (range, 1.9-3.5 mmol/L), and the mean ferritinemia level was 4,246 μg/L (range, 2,424-7,612 μg/L). All patients had hemophagocytosis on bone marrow smears. Finally, all patients received etoposide. The mean length of stay was 7 days (range, 3-14 days) in the ICU and 21 days (range, 8-28 days) in the hospital. Three patients (33%) died in the ICU, and hospital mortality was 56% (five deaths).