Antierythropoietin antibodies in thalassemia patients.

We evaluated sera from 58 thalassemic patients for the presence of antierythropoietin antibodies to investigate whether these autoantibodies may relate with modest response to treatment with recombinant human erythropoietin (rhEpo). Thirty-seven patients had beta-thalassemia major, 9 patients had beta-thalassemia intermedia, and 12 patients had sickle/beta(+)-thalassemia. Of 58 patients, 24 were on rhEpo treatment in order to increase the intervals between transfusions or the hemoglobin (Hb) values. The study population was divided into three groups according to rhEpo treatment. Group A consisted of 15 patients who were on rhEpo treatment (400-600 IU/kg three times per week, subcutaneously) showing an increase of Hb values or reduction of transfusion requirements. Group B included 9 patients who did not respond to rhEpo and group C consisted of 34 patients who did not receive rhEpo. Laboratory studies included a complete blood count, measurement of serum erythropoietin, immunological evaluation, and determination of antierythropoietin antibodies using enzyme-linked immunosorbent assay (ELISA). There were no significant differences among groups A, B, and C concerning age, Hb, and endogenous erythropoietin values. Fifteen patients had positive antinuclear antibodies and three patients had positive rheumatoid factor. Antierythropoietin antibodies were detected in the sera of seven patients (five men and two women) who received rhEpo. The male patients and one female patient had no response to rhEpo while the other female patient showed response when the dose increased. Other autoantibodies seem to have no clinical significance. In the present study, we detected for the first time in thalassemia patients the presence of antierythropoietin antibodies, which may contribute to rhEpo resistance. Thalassemia patients with low response rates to rhEpo should be evaluated for the presence of antierythropoietin antibodies.