Proinflammatory cytokines, particularly tumor necrosis factor α (TNF-α), interleukin 6 (IL-6) and IL-1 play important roles in the pathogenesis of RA and are thought to contribute to the development of RA-anemia by modulating iron metabolism and suppressing bone marrow erythropoiesis [5-7]. This evidence concerns the gene IL1B and anemia (phenotype).