Linfohistiocitosis hemofagocítica, el espectro desde la enfermedad genética al síndrome de activación macrofágica

hemophagocytic lymphohistiocytosis is characterized by a severe hyperinflammatory condition, with macrophages and t cells activation and expansion, without regulatory pathways for the termination of the inflammatory activity. hemophagocytic syndromes are clinical translation of an overwhelmed inflammatory response. the term hemophagocytic lymphohistiocytosis applies to all the variants of the syndrome and macrophage activation syndrome refers to the variant associated with autoimmune diseases. primary cases are related to a familiar autosomic recessive disease and the secondary ones to primary immunodeficiencies, infection, malignancy and autoimmune diseases. physiopathology of the disease is related mainly to the aggressive macrophage and histiocyte proliferation and phagocytosis of blood cells. an impaired function of nk cells and cytotoxic t-cells, increase cell activation and expansion and cytokine production inducing macrophage activation, tissue infiltration and tissue damage. the main symptoms are prolonged fever, cytopenias, hepatosplenomegaly, and hemophagocytosis. biochemical markers include elevated ferritin and triglycerides and low fibrinogen. bone marrow hemophagocytosis is present in more than 80% of the cases at diagnosis. treatment targets activated t-cells an histiocytes, combining chemotherapy, immunosuppressors and in selected cases hematopoyetic stem cell transplantation. treatment produced a positive change in patient survival. hlh-2004 treatment protocol is an standarized guideline that combine etoposide, dexamethasone and cyclosporine a. in costa rica 60 cases have been reported in children, with a 44% mortality.