Influence of Inflammatory Cytokines on the Response to Erythropoietin Treatment in RA Patients.

32 patients with rheumatoid arthritis (RA) undergoing arthroplasy were treated with intravenous recombinant human erythropoietin (EPO) in order to donate autologous blood. The patients received 6000 units of EPO and 40mg of iron 3 times a week and autologous blood was collected after erythropoiesis. All cases except one were able to avoid homologous blood transfusion during or after operation. Since responses to EPO were extremely different among these patients, we investigated the factors, including serum cytokine levels, which influenced on the patient's response to EPO. The response correlated negatively with initial erythrocyte sedimentation rate, serum CRP levels and serum TNF-α levels. There was no relation between the response to EPO and IL-1β or IL-6 levels. These results suggest that the response to EPO depends on activity of RA and also indicate that TNF-α, one of the most important cytokines in RA, is the major inhibitor of erythropoiesis in RA patients.