Mycobacterium tuberculosis (Mtb), a lung pathogen, is dependent on iron acquisition to successfully colonize the human host. Mtb secretes siderophores to acquire iron from host transferrin, ferritin and lactoferrin, but the siderophores cannot access iron in heme (Hm) or hemoglobin (Hb), which store greater than 75% of host iron. Recently, it was shown that the necrotic centers of TB granulomas (infected macrophages) contain high concentrations of host Hm- and Hb- sequestering proteins to limits access of Mtb to Hm iron. This observation is particularly relevant in the context of the Mtb life cycle because: 1) macrophages play a key role in the recycling of senescent erythrocytes for Hb production in new erythrocytes and 2) Mtb resides and replicates within host macrophages.