RESUMO
Transferrin receptors are used by rapidly dividing tissues such as bone marrow for the extraction of iron necessary for their metabolic requirements. As cells in the erythropoietic series mature, transferrin receptors are cleaved from the cell surface and may be measured free in the plasma. Serum transferrin receptors (STR) levels are therfore believed to reflect the extent of erythropoiesis and are elevated in anaemias associated with iron deficiency, haemolysis and thalassaemia and decreased in aplastic anaemia. Levels have been measured in stored sera from 182 children with homozygous sickle-cell (SS) disease and 42 controls with a normal haemoglobin (AA) genotype age 8 years (ñ 3 months) in a cohort study from birth. Levels is SS children (mean, SD: 38.3, 12.7) greatly exceeded those in AA controls (6.7, 1.9) (test = 32.1, p0.001) and were negatively correlated with total haemoglobin and foetal haemoglobin levels in both sexes but not with reticulocyte counts. The serum transferrin receptor level may be a useful indicator of the degree of eryreticulocyte counts. The serum transferrin receptor level may be a useful indicator of the degree of erythropoietic expansion in SS disease, and requires further study to determine its clinical value (AU)