Iron stores and serum transferrin receptor levels during recombinant human erythropoietin treatment of anemia in rheumatoid arthritis.

Ten rheumatoid arthritis (RA) patients with anemia of chronic disorders (ACD) were treated with recombinant human erythropoietin (r-Hu-Epo) using a dose of 250 U/kg s.c. 3 times a week for 6 weeks, in order to evaluate its effects on the anemia, iron stores, and serum-soluble transferrin receptor (sTfR) levels. All patients showed a rise in hemoglobin (Hb). Median Hb increased from 5.9 (5.5-7.0) at baseline to 6.7 (5.8-7.8) at 3 weeks and to 7.2 (5.9-8.5) mmol/l at 6 weeks during treatment. Ferritin levels decreased significantly during the 6 weeks, and five patients were iron deficient after 6 weeks of treatment. TfR levels increased significantly at 3 and 6 weeks during treatment. These preliminary findings may indicate that r-Hu-Epo is effective in improving ACD in RA. The sTfR rise may be explained by an increase in erythroid precursor cell mass or increased TfR expression and a decrease in tissue iron stores, although direct effects of Epo on TfR regulation cannot be excluded. Large double-blind studies with r-Hu-Epo in patients with RA and ACD are warranted.