Abstract
Although some biochemical and metabolic properties of the isoferritin in erythroid cells designated “erythroblast or red cell ferritin” were previously reported, clinical or pathophysiologic significance of red cell ferritin quantitation remains to be clarified. However, the recent development of a sensitive immunoradiometric assay method for ferritin has made it possible to quantitate ferritin in blood cells as well as serum. This report describes the results of red cell ferritin measurements in normals and hematologic disorders by the two site radioimmunoassay method and of some analysis undertaken to reveal factors regulating red cell ferritin concentration. The results obtained revealed two important points indicating clinical and pathophysiologic significance of red cell ferritin measurement. The first one demonstrated is that red cell ferritin constitutes a functional metabolic pool which shows variable sensitive changes dependent on some intrinsic and extrinsic factors. The second point disclosed is that red cell ferritin concentrations in hematologic disorders show characteristic changes among disorders which were found to be regulated by three main factors, iron store, reticulocyte percentage and disturbance of hemoglobin synthesis or ineffective erythropoiesis. Significant correlation between serum iron values and red cell ferritin concentrations was observed in most hematological disorders except ones with ineffective erythropoiesis or disturbed hemoglobin synthesis. This fact revealed that the level of transferrin-bound iron is a direct extrinsic factor determining red cell ferritin levels. It was also found that red cell ferritin concentrations show remarkable changes during the treatment of hematologic disorders such as iron deficiency anemia, pernicious anemia and polycythemia vera. The density gradient centrifugation analysis demonstrated that red cell ferritin posses a higher molecular density than serum ferritin which is similar to that of liver ferritin. These results presented in this paper disclosed not only the clinical significance of red cell ferritinmeasurements but also some physiologic or pathophysiologic nature of red cell ferritin in humans.
