[Macrophage activation syndrome: report on three cases].

The macrophage activation syndrome (MAS) is a rare and potentially fatal disease. This syndrome is founded on congenital or acquired dysfunction of NK cells resulting in secondary activation and proliferation of macrophages with excessive cytokine production and organ infiltration. Causes of acquired MAS include viral infections (chiefly EBV and CMV), malignancies, and autoimmune diseases. The macrophage activation syndrome is usually associated with juvenile idiopathic arthritis and adult-onset Still's disease and rarely with rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, and systemic sclerosis. Fever, hepatosplenomegaly, lymphadenopathy, and bi- or pancytopenia in peripheral blood represent typical symptoms of MAS. Hyperferritinemia, hypertriglyceridemia, hypertransaminasemia, and hypofibrinogenemia are among the common laboratory findings. The macrophage activation syndrome is a life-threatening condition requiring aggressive therapy due to multiple organ dysfunction. Treatment also includes elimination of the triggering infection and high-dose glucocorticosteroids. Second-line therapy is based on cyclosporin, intravenous immunoglobulins, and etoposide. The present work focuses on diagnostic and therapeutic difficulties in three patients with the macrophage activation syndrome.