We found that the percent of immature RBCs CD71+, reticulocytes expressing the transferrin receptor on the cell surface was lower in the hypersplenism vs. asplenia/hyposplenism group (mean % 1.5 ± 0.4 vs. 4.2 ± 2.1; respectively, p = 0.013). The gene discussed is TFRC; the disease is hypersplenism.