Desferrioxamine Chelatable Iron in Haemolytic, Megaloblastic and Sideroblastic Anaemias*

Abstract

SUMMARY The chelation of body iron by desferrioxamine methanesulphonate in patients with haemolytic anaemias of varying types, in megaloblastic and in sideroblastic anaemias was measured by the differential ferrioxamine test. Thirty‐five out of 44 patients studied had chelation values above the normal range, sometimes exceeding those found in untreated haemochromatosis. In the haemolytic anaemias, the amount of chelation increased with the severity of the anaemia. In the megaloblastic anaemias, specific therapy reduced the amount of iron chelated by desferrioxamine at the same time as normal erythropoiesis was re‐established. Concepts of labile iron and metabolically active iron are compared with desferrioxamine chelatable iron. These findings suggest that in addition to storage iron (ferritin‐haemosiderin) chelated with difficulty, there is a compartment of readily chelatable iron derived from haem catabolism, possibly sited in reticulo‐endothelium. A model of intracellular iron transport in reticulo‐endothelial cells is proposed which provides a primary pathway of metabolically active, highly chelatable iron derived from haemoglobin catabolism, and a secondary pathway to intracellular ferritin.