The iron islands: Erythroblastic islands and iron metabolism

Abstract Background A healthy human can produce over 1 × 10 15 blood cells throughout their life. This remarkable amount of biomass requires a concomitantly vast amount of iron to generate functional haemoglobin and functional erythrocytes. Scope of the review Erythroblasts form multicellular clusters with macrophages in the foetal liver, bone marrow and spleen termed erythroblastic islands. How the central erythroblastic island macrophage co-ordinates the supply of iron to the developing erythroblasts will be a central focus of this review. Major conclusion Despite being studied for over 60 years, the mechanisms by which the erythroblastic island niche serves to control erythroid cell iron metabolism are poorly resolved. General significance Over 2 billion people suffer from some form of anaemia. Iron deficiency anaemia is the most prevalent form of anaemia. Therefore, understanding the processes by which iron is trafficked to, and metabolised in developing erythrocytes, is crucially important.