EPO and anemia (phenotype): According to Casadevall et al., rHuEPO-associated PRCA is a rare clinical syndrome defined by three criteria: resistance to EPO therapy; anemia accompanied by reticulocytopenia (<10 × 109/L) during rHuEPO therapy, either with or without the need for transfusions due to erythroblastopenia in morphologically normal bone marrow; and the presence of neutralizing anti-EPO antibodies [1].