Haemophagocytic syndrome associated with infections

Haemophagocytic syndromes (HS) are the clinical manifestation of an increas ed macrophagic activity with haemophagocytosis. Pathophysiology is related to a deregulation of T-lymphocytes and excessive production of cytokines. T he main clinicobiological features are fever, hepatosplenomegaly, adenopath ies, skin rash, neurological features, cytopenias, hypertriglyceridaemia, h yperferritinaemia and coagulopathy. Diagnosis is based on examination of th e bone marrow which shows benign histiocytes actively phagocytosing haemopo ietic cells. Acquired HS are mostly associated with an underlying disease s uch as immunodeficiency, haematological neoplasias and autoimmune diseases. Infection-associated HS was originally described by Risdall in 1979, in vi ral disease. Since the initial description HS has also been documented in p atients with bacterial, parasitic or fungal infections. Epstein-Barr virus (EBV) is the causative agent in most cases. In EBV-associated HS, which som etimes has a fatal course, unregulated T-cell reaction or uncontrolled B-ce ll proliferation may release cytokines. Management of HS consists of early diagnosis, careful screening for, and prompt treatment of, infections and d etection and therapy of any underlying disease. Prognosis of infection-asso ciated haemophagocytic syndrome (IAHS) is better than that in other types o f secondary HS. Management of cytokine imbalance should be useful to improv e the outcome and reduce the mortality rate in these cases.