Anemia of chronic disease (ACD) or anemia of chronic inflammation is a form of anemia seen in chronic infection, chronic immune activation, and malignancy. These conditions all produce elevation of interleukin-6, which stimulates hepcidin production and release from the liver, which in turn shuts down ferroportin, a protein that controls export of iron from the gut and from iron storing cells (e.g. macrophages). As a consequence, circulating iron levels are reduced. Other mechanisms may also play a role, such as reduced erythropoiesis. It is also known as anemia of inflammation, or anemia of inflammatory response. Classification
Anemia of chronic disease is usually mild but can be severe. It is usually normocytic, but can be microcytic. The presence of both anemia of chronic disease and dietary iron deficiency results in a more severe anemia. Pathophysiology
Anemia is defined by hemoglobin (Hb) concentration

< 13.0 g/dL (130 g/L) in males
< 11.5 g/dL (115 g/L) in femalesIn response to inflammatory cytokines, increasingly IL-6, the liver produces increased amounts of hepcidin. Hepcidin in turn causes increased internalisation of ferroportin molecules on cell membranes which prevents release from iron stores. Inflammatory cytokines also appear to affect other important elements of iron metabolism, including decreasing ferroportin expression, and probably directly blunting erythropoiesis by decreasing the ability of the bone marrow to respond to erythropoietin. Before the recent discovery of hepcidin and its function in iron metabolism, anemia of chronic disease was seen as the result of a complex web of inflammatory changes.
These cells require iron for their massive amounts of hemoglobin which allow them to transport oxygen.Because anemia of chronic disease can be the result of non-infective causes of inflammation, future research is likely to investigate whether hepcidin antagonists might be able to treat this problem. Anemia of chronic disease may also be due to neoplastic disorders and non-infectious inflammatory diseases. Neoplastic disorders include Hodgkin disease and lung and breast carcinoma, while non-infectious inflammatory diseases include celiac disease, rheumatoid arthritis, systemic lupus erythematosus, scleroderma and dermatomyositis. Anemia of chronic disease, as it is now understood, is to at least some degree separate from the anemia seen in kidney failure in which anemia results from reduced production of erythropoietin, or the anemia caused by some drugs (like AZT, used to treat HIV infection) that have the side effect of inhibiting erythropoiesis. In other words, not all anemia seen in people with chronic disease should be diagnosed as anemia of chronic disease. On the other hand, both of these examples show the complexity of this diagnosis: HIV infection itself can produce anemia of chronic disease, and kidney failure can lead to inflammatory changes that also can produce anemia of chronic disease. Diagnosis
While no single test is reliable to distinguish iron deficiency anemia from the anemia of chronic inflammation, there are sometimes some suggestive data:

In anemia of chronic inflammation without iron deficiency, ferritin is normal or high, reflecting the fact that iron is sequestered within cells, and ferritin is being produced as an acute phase reactant.