Table 1.

Similarities between hemophagocytic lymphohistiocytosis (HLH) 2004 criteria and features of viral hemorrhagic fever (VHF). Adapted from Chatham and Cron. The Rheumatologist 2014;8:1,21–236; with permission.

HLH-04 CriteriaFeatures of VHF
Bicytopenia or pancytopeniaFrequently
Hypertryglyceridemia or hypofibrinogenemiaBoth have been reported for some hemorrhagic fever viruses
Hemophagocytosis on biopsyYes, for the viruses studied
Hyperferritinemia (> 500 ng/ml)Yes, often > 10,000 ng/ml
Elevated soluble CD25Yes, for the viruses studied
Absence of decreased natural killer cell functionPoorly studied to date