SERUM ERYTHROPOIETIN AND SERUM TRANSFERRIN RECEPTOR LEVELS IN APLASTIC-ANEMIA

Serum erythropoietin (EPO) and soluble transferrin receptor levels wer e serially measured in 74 patients with aplastic anaemia (AA). As cont rol groups we investigated healthy controls (n = 24) and patients with iron-deficiency (n = 23) or haemolytic anaemia (n = 16). There was a significant negative correlation of log EPO on haematocrit both in AA patients and in the anaemic control group. However, for the same degre e of anaemia, log EPO levels in AA were significantly higher than in i ron-deficiency or haemolytic anaemia. EPO levels at diagnosis did not correlate with severity of aplastic anaemia, nor did they predict outc ome after immunosuppression. During immunosuppressive treatment of AA with anti-thymocyte globulin and cyclosporine A, EPO levels were signi ficantly lower compared with pre-treatment values without a correspond ing change in haematocrit. This impaired EPO response to anaemia durin g immunosuppression might affect recovery of erythropoiesis. In AA pat ients, EPO levels declined with haemopoietic recovery. However, compar ed with normal controls, EPO levels in remission patients were still h igher with respect to their haematocrit. Results of this study argue a gainst the model of a simple feedback regulation of EPO via hypoxic an aemia. Our data support the hypothesis that cytokines and the erythrop oietic progenitor pool are involved in the regulation of EPO productio n. The results illustrate that serial measurements of EPO along with t herapeutic interventions are necessary to identify patients who might benefit from treatment with exogenous recombinant human EPO.