However, rapid cellular apoptosis from alpha globin chain precipitation, and relatively low levels of endogenous erythropoietin (EPO) in some beta(+) thalassemia patients contribute to the anemia in beta thalassemia syndromes.
In comparison, individuals with beta-thalassemia syndromes had elevated GDF15 serum levels (mean 66,000 +/- 9,600 pg/ml; range 4,800-248,000 pg/ml; P < 0.05) that were positively correlated with the levels of soluble transferrin receptor, erythropoietin and ferritin.
Recent studies established that hypoxia and/or hypoxia-induced erythropoietin are not direct regulators of hepcidin, which is indirectly inhibited by erythropoietic drive, in particular under pathological conditions characterized by expanded but ineffective erythropoiesis, such as β-thalassemia.
The ability of circulating progenitor cells to develop erythroid colonies was studied in vitro in the presence or absence of growth factors (5637-CM and erythropoietin) in 63 patients with sickle cell disease (SCD) (36 homozygotes for hemoglobin [Hb] S, 13 double heterozygotes for Hb S and beta thalassemia, and 14 SC patients) in Southeast Brazil.