THE DETERMINATION OF PLASMA TRANSFERRIN RECEPTOR AS GOOD INDEX OF ERYTHROPOIETIC ACTIVITY IN RENAL ANEMIA AND AFTER RENAL-TRANSPLANTATION

Both the plasma determinations of erythropoietin (EPO) and transferrin receptor (TfR) would provide a good characterization of anemia especi ally when mixed erythron disorders underlie, such as in renal failure. Immunologic assays of EPO and TfR, as well as standard hematologic de terminations (hematocrit, reticulocyte count, serum iron, transferrin, ferritin) were performed in patients with chronic renal failure (CRF) , in regular dialysis treatment (RDT) and in transplanted (TX) patient s. In nonanemic TX patients both EPO and TfR ranged normally, whereas in anemic TX ones (Hct <40%) both values were increased suggesting the physiologic response both of the kidney and of the erythron to decrea sed red cell mass. In transitory posttransplant erythrocytosis the inc reased values of TfR, with normal EPO values, would hypothesize a defe ctive feedback to EPO release. Both EPO and TfR values were found incr eased in TX patients with adult polycystic kidney disease with persist ent erythrocytosis (Hct >50%), thus confirming previous observations. In CRF and RDT patients, all anemic, both EPO and TfR were normal, eve n though significantly low with respect to the degree of anemia. In RD T seriously anemic patients, the administration of recombinant human E PO induced different patterns of bone marrow response. We conclude tha t the determination of TfR would provide further information on renal anemia since the receptor increase mostly preceded the rise of Hct, ev idencing those patients who will not have an effective bone marrow res ponse to the therapy.