Purpose: To investigate the response of erythropoietin (EPO) to anemia in patients polytransfused for beta-thalassemia major.
Patients and methods: We measured the serum EPO levels and the concurrent hemoglobin (Hb) concentrations in 40 patients polytransfused for beta-thalassemia major, in 18 patients with iron deficiency anemia (IDA), and 32 healthy subjects. Serum EPO levels were assayed by an enzyme immunoassay.
Results: In both groups with beta-thalassemia major and IDA, serum EPO levels were significantly elevated (114 +/- 71 and 239 +/- 217 mU/mL, respectively). There was a significant inverse correlation between log EPO values and Hb concentrations in patients with beta-thalassemia major (r = 0.61; p < 0.01) and IDA (r = 0.81; p < 0.01). In a semilogarithmic plot, the slope of the regression line obtained in patients with beta-thalassemia major was significantly lower than that of IDA (p < 0.01), suggesting a blunted EPO response to anemia in patients polytransfused for beta-thalassemia major. The elevation of serum EPO in patients with beta-thalassemia major was poorly related to clinical variables except serum ferritin.
Conclusions: We conclude that a significant inverse relationship between serum EPO levels and Hb concentration exists in patients with beta-thalassemia major. However, this EPO response in patients with anemia caused by beta-thalassemia major may be blunted when compared to patients with IDA.