Hemophagocytic lymphohistiocytosis (HLH) is a reactive condition marked by cytopenias and signs and symptoms of systemic inflammation related to macrophage activation. it is also sometimes referred to as macrophage activation syndrome. familial and may appear early in life, even in infants, while other forms are sporadic and may affect people of any age. The common feature of all forms of HLH issystemic activation of macrophages and CD8+ cytotoxic T cells. the “stew” of mediators released from macrophages and lymphocytes suppress hematopoiesis and produce symptoms of systemic inflammation. These effects lead to cytopenias and a shock-like picture, sometimes referred to as “cytokine storm” or the systemic inflammatory response syndrome Clinical Features. Most patients present with an acute febrile illness associated with splenomegaly and hepatomegaly. Hemophagocytosis is usually seen on bone marrow examination, but is neither sufficient nor required to make the diagnosis. Laboratory studies reveal anemia, thrombocytopenia, and very high levels of plasma ferritin and soluble IL-2 receptor.Coagulation studies may show evidence of disseminated intravascular coagulation. Treatment involves the use of immunosuppressive drugs and “mild” chemotherapy. Patients with germline mutations that cause HLH or who have persistent/resistant disease are candidates for hematopoietic stem cell transplantation. familial forms of the disease, who typically survive for less than 2 months.