Hepcidin, a β-defensin-like antimicrobial peptide, is part of the innate immune system and thus constitutes the first-line defense against infections. In vivo and in vitro studies have demonstrated that hepcidin is active against Gram-positive and Gram-negative bacteria as well as yeasts . In addition to its antimicrobial activity, it acts as an iron regulatory hormone. Increased hepcidin synthesis inhibits iron flow into plasma from macrophages that have taken up and degraded senescent erythrocytes as well as their hemoglobin, and also from small intestinal epithelial cells involved in the absorption of dietary iron . This iron release from cytoplasmic stores is prevented by binding of hepcidin to the iron exporter protein ferroportin. Ferroportin is internalized and degraded upon hepcidin activity.