Serum transferrin receptor as a marker of erythropoiesis suppression in patients on chronic transfusion
Iron Chelating Agents
In the management of patients requiring chronic transfusion, various parameters may be used to evaluate the degree of erythroid marrow suppression. The aim of our study was to assess which of these parameters provide the most useful assessment of erythropoiesis. We studied 27 chronically transfused patients, 19 with sickle cell disease (SS patients) and 8 with thalassemia. Thirty-one nonchronically transfused SS patients and 74 healthy children served as controls. We measured serum transferrin receptor levels, reticulocyte counts, hemoglobin (Hb) concentrations and erythropoietin levels. The serum transferrin receptor levels were very elevated in control SS patients and remained significantly elevated in those on transfusion therapy, but were normal in thalassemia patients, indicating a more complete suppression of erythropoiesis. The reticulocyte counts were elevated in all SS patients, even when on chronic transfusion, but were in the normal range in patients with thalassemia. Erythropoietin levels were elevated in patients with thalassemia and in all the SS patients. Hb levels negatively correlated with serum transferrin receptor and erythropoietin in all SS patients. In the transfused SS patients, a higher HbS level correlated with higher reticulocyte counts, transferrin receptor, and erythropoietin levels. In thalassemia patients, erythropoiesis was more completely suppressed, as reflected both by normal reticulocyte counts and near-normal transferrin receptor levels. Though the reticulocyte counts were not significantly different in the transfused SS patients, the serum transferrin receptor levels were less elevated than in SS patients not on transfusion. The serum transferrin receptor level appears to be the most useful marker of marrow erythropoietic activity in chronically transfused SS patients. We recommend that reticulocyte counts be integrated with periodic measurements of serum transferrin receptor levels.