Table 1.

HLH-2004 guidelines for diagnosis of HLH

HLH-2004 requires 1 or 2 of the below to be fulfilled
1. Molecular diagnosis consistent with HLH
2. Diagnostic criteria with 5 of 8 of the following symptoms:
Fever
Splenomegaly
Cytopenias affecting >2 lineages in PB
Hemoglobin <9 g/dL (<10 g/dL in infants <4 wk of age)
Platelets <100 000/μL
Neutrophils <1000/μL
Hypertriglyceridemia: fasting triglycerides >265 mg/dL and/or hypofibrinogenemia: <1.5g/L
Hemophagocytosis in the BM, spleen, lymph nodes, or liver
Low or absent NK cell activity
Ferritin >500 μg/L
Increased soluble CD25 (IL-2r) concentration: >2400 U/mL

The guidelines for HLH are presented in the text. Additionally, several other characteristics are associated with HLH including cerebrospinal fluid pleocytosis, elevated cerebrospinal fluid protein, liver histology consistent with chronic persistent hepatitis, cerebromeningeal symptoms, lymphadenopathy, skin rash, hypoproteinemia, hyponatremia, increased very low-density lipoprotein, or decreased HDL.

PB, peripheral blood.