Interleukins produced by Th1 cells, such as IFN-γ, would play a role in the pathogenesis of anemia through inhibition of the earliest stages of erythroid differentiation and proliferation [51], alteration of iron homeostasis, induction of iron retention in macrophages, and consequent limitation of iron availability during erythropoiesis [49,51,52]. This evidence concerns the gene IFNG and anemia (phenotype).