[Disturbancies of iron utilization: chronic anaemia, sideroblastic anaemia, and residual endothelial siderosis...

Knowledge of disturbancies of iron utilization has been considerably extended by histochemical-ultrastructural findings and the results of immunoradiometric assays for serum ferritin. -- In chronic anaemia due to infections or neoplastic diseases hyposideraemia and normal unsaturated iron binding capacity were associated with increased iron retention in macrophages and slightly to highly increased serum ferritin (500--4000 ng/ml). -- 117 patients with sideroblastic anaemia formed a heterogenous group of diverse aetiology. The iron granules of ringed sideroblasts contained nonferritin iron in mitochondria. At diagnosis, a normal iron status was found in single cases. More frequently, praelatent and latent iron overload with ferritin levels up to more than 2000 ng/ml were observed. Manifest iron overload with tissue damage was mostly the result of numerous transfusions (ferritin 4700 bis 9500 ng/ml). -- After i.v. application of colloidal iron endothelial siderosis was a regular finding. The typical uniform granules representing nonferritin-iron in lysosomes disappeared in the course of 1--3 years completely. In contrast, the colloidal iron taken up simultaneously by the macrophages was rapidly transformed into ferritin and easily used up for haemoglobin synthesis when required. The corresponding increase of serum ferritin up to maximal 4000 mg/ml was dose related. Continued blood losses lead to residual endothelial siderosis after exhaustion of macrophageal iron and recurrence of iron deficiency anaemia. The serum ferritin fell to low levels (0--12 ng/ml) as observed in untreated cases.