The pathophysiological mechanisms underlying anemia of chronic disease are cytokines such as TNF-α, interleukin-1, interleukin-6, and interleukin-10 produced by immune system reaction to the invasion of microorganisms, which induce ferritin expression and stimulate the storage and retention of iron within macrophages and inhibit duodenal absorption of iron and the differentiation and proliferation of erythroid progenitor cells, and so forth, which lead to iron deficiency anemia. This evidence concerns the gene TNF and anemia (phenotype).