Anemia of chronic disease: illness or adaptive mechanism.

The anemia of chronic disease (ACD) is the most prevalent anemia after iron deficiency anemia. It is associated with infectious, inflammatory and neoplastic disease. ACD is a medical condition caused by the release of cytokines which mediate inflammatory and immune response (tumor necrosis factor, interleukins 1 and 6, and interferon). Abnormal iron metabolism with iron trapping in reticuloendothelial cells is primarily the cause of this condition, making iron unavailable for erythropoiesis although iron tissue reserves are elevated. Disorder in erythropoietin secretion and shortening of red cell life span also play a role in the pathogenesis of ACD. The main therapy is treatment of the underlying disorder and red cell transfusions in severe anemia. In more severe (protracted) anemias that lead to impaired quality of life and have an impact on the mortality and survival rate, erythropoiesis stimulating agents are used. Recently, new possibilities are being evaluated in terms of therapy for ACD in defined conditions, such as chelating agents, as well as hepcidin antagonist and other erythropoiesis stimulating agents.