[Anemia in patients with rheumatoid arthritis]

One of the most frequent extra-articular organ manifestations in rheumatoid arthritis (RA) is anemia. As anemia in RA patients may result in severe symptoms and aggravation of other disease manifestations (e.g. arteriosclerosis), the influence on the course of RA is profound. However, the importance of anemia in RA patients is frequently underestimated. The etiology of anemia in RA is complex. Anemia of inflammation (AI) and iron deficiency anemia, alone or in combination are the most frequent forms of anemia in RA. Changes in iron metabolism are the leading causes of anemia in RA patients and mainly induced by the altered synthesis and function of hepcidin and ferroportin. Hepcidin, a peptide produced in the liver and immunocompetent cells, impairs the expression of ferroportin on iron-secreting cells, thus reducing iron bioavailability. The typical changes of iron metabolism and hepcidin synthesis in RA are induced by proinflammatory cytokines, primarily interleukin-6. Hence, the treatment of RA with cytokine antagonists has significant therapeutic implications on anemia in the context of inflammation and impaired iron metabolism.