Hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis
Updated: 08/04/2020
© Jun Wang, MD, PhD

General features
  • Generalized, non-malignant histiocytosis
  • Rare but aggressive and life threatening
  • Excessive activation of immune activity
  • Familial: infants/young children, autosomal recessive
  • Acquired: EBV+ immunocompromised, or associated with other infections or malignancy
  • May develop from Chediak-Higashi syndrome
  • May involve any organ
  • Repeated biopsy of bone marrow, lymph nodes, etc if necessary for diagnosis
Clinical presentations
  • Acute febrile illness
  • Splenomegaly and hepatomegaly
  • Lymphadenopathy
  • Skin rash
Key pathogenesis
  • Abnormal activation of macrophages
  • Over expression of calreticulin (CRT)
  • Underexpression of CD47
Key Laboratory findings
  • Pancytopenia
Key morphological features
Indicators for diagnosis
  • Fever with hepatosplenomegaly and cytopenia, as well as elevated ferritin
Genetic abnormalities
  • If familial, associated with various genes such as perforin, etc



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