Prospective Cohort for Adult Hemophagocytosis

Study process is as follows.

• Informed consent for subjects fulfilling the inclusion criteria.
• Laboratory evaluation will be done for subjects according to the following diagnostic criteria.

• Diagnosis will be established if one of either 1 or 2 below is fulfilled

• A molecular diagnosis consistent with HLH
• Diagnostic criteria for HLH fulfilled (5 out of 8 criteria below)
• fever ≥ 38.5'C for ≥ 7 days
• splenomegaly ≥ 3 finger breadth below left subcostal margin
• cytopenias affecting ≥2 of 3 lineages in peripheral blood (Hemoglobin < 9 g/L, Platelets < 100 × 109/L, Absolute neutrophil count < 1.0 × 109/L)
• Hypertriglyceridemia and/or hypofibrinogenemia: Fasting triglycerides ≥ 265 mg/dL, fibrinogen ≤ 1.5 g/L
• Hemophagocytosis in bone marrow or spleen or lymph node
• Low or absent NK-cell activity (according to local laboratory reference)
• Ferritin ≥ 500 mcg/L
• Soluble CD25 (sIL-2 receptor) ≥ 2,400 U/mL

Inclusion criteria

• Subjects should fulfill the following criteria

• Subjects should have at least one of the following problems

• Presence of hemophagocytosis in tissue or bone marrow
• Presence of at least 3 conditions among 8 conditions of HLH diagnostic criteria
• Age > 18 years
• Written informed consents

Exclusion criteria

• Subjects cannot satisfy the inclusion criteria