Hemophagocytic lymphohistiocytosis (HLH) is a frequently fatal and likely underdiagnosed disease involving a final common pathway of hypercytokinemia, which can result in end-organ damage and death.
Although an early diagnosis is crucial to decrease mortality, the definitive diagnosis is often challenging because of the lack of specificity of currently accepted diagnostic criteria and the absence of confirmatory gold standards.
Diagnostic Criteria of Hemophagocytic Lymphohistiocytosis (HLH)
Molecular diagnosis of HLH or the presence of at least 5 of 8 criteria:
- Cytopenias (affecting at least 2 lineages in the peripheral blood)
Hemoglobin levels <90 g/L (in infants <4 weeks old,
hemoglobin <100 g/L)
Platelets <100,000 × mm³
Neutrophils <1,000 × mm³
- Hypertriglyceridemia and/or hypofibrinogenemia:
Fasting triglycerides ≥3.0 mmol/L (ie, ≥265 mg/dL)
Fibrinogen ≤1.5 g/L
- Documented hemophagocytosis in the bone marrow, spleen, or lymph nodes
- Low or absent natural killer cell activity
- Ferritin ≥500 mg/L
- Soluble CD25 (ie, soluble interleukin-2 receptor) ≥2,400 U/mL
- Campo M, Berliner N. Hemophagocytic Lymphohistiocytosis in Adults. Hematol Oncol Clin North Am. 2015 Oct;29(5):915-25. [Medline]
- Rosado FG, Kim AS. Hemophagocytic lymphohistiocytosis: an update on diagnosis and pathogenesis. Am J Clin Pathol. 2013 Jun;139(6):713-27. [Medline]
- Bhatt NS, Oshrine B, An Talano J. Hemophagocytic lymphohistiocytosis in adults. Leuk Lymphoma. 2018 Jul 3:1-10. [Medline]
Created Sep 24, 2018.