Serum erythropoietin levels in thalassemia major and intermedia.

Serum erythropoietin (EPO) levels were determined by enzyme linked immunosorbent assay (ELISA) in 61 thalassemic patients, consisting of 23 thalassemia major (TM) patients with multiple transfusion, 38 patients with thalassemia intermedia (TI). Thirty-two normal controls were also studied. The mean serum EPO levels were significantly higher in both groups with TM (165.96 +/- 17.31 mlU/ml) and TI (126.43 +/- 50.56 mlU/ml) compared with the control group (8.33 +/- 3.91 mlU/ml). The mean value of hematocrit (Hct) in the patients with TM (18.70 +/- 3.51%) was lower than those with TI (25.24 +/- 4.19 %) whereas the mean serum EPO level were significantly higher in TM than TI patients. An inverse correlation between the serum values of EPO and Hct was observed in both TI and TM patients, however this correlation was significant only in TI (r = -0.61, p<0.001). These data showed that serum EPO levels increased in all thalassemia patients despite repeated transfusion. Multiple transfusion may modulate the response of serum EPO to the degree of anemia, resulting in increased EPO levels and independent anemia in the TM patients.