Daintain/AIF-1 (allograft inflammatory factor-1) promotes erythrocyte lysis and heme release probably via binding to hemoglobin.

Free heme is potentially cytotoxic, particularly in the presence of oxidants or activated phagocytes. Daintain/AIF-1 (allograft inflammatory factor-1) is a macrophage factor that has been implicated in the regulation of inflammation. In the present study, daintain/AIF-1 was found to induce cytolysis of erythrocytes, resulting in heme release in vitro. Furthermore, the interacting protein of daintain/AIF-1 was purified by daintain/AIF-1-6 histidine antigen fusion protein nickel affinity chromatography. MALDI-TOF-MS analysis identified hemoglobin subunit beta-1 as an interacting protein of daintain/AIF-1. These data suggest that daintain/AIF-1 may be involved in heme-associated diseases.