The haemophagocytic syndrome.

The haemophagocytic syndrome or haemophagocytic lymphohistiocytosis (HLH) is a syndrome encompassing a heterogeneous group of disorders characterized by a persistent activation of benign macrophages, leading to uncontrolled secretion of cytokines and phagocytosis of blood cells. The syndrome can be primary due to mutations in different genes crucially involved in lymphocyte cytotoxicity and secondary in association with infectious, autoimmune or malignant disorders. In most cases HLH displays an aggressive disease course with a high fatality rate without treatment. Early recognition of the syndrome and prompt initiation of appropriate treatment, in most cases consisting of immunochemotherapy, are mandatory to ensure long-term survival.