Hydroxyurea responses and fetal hemoglobin induction in β-thalassemia/HbE patients’ peripheral blood erythroid cell culture

Due to genetic heterogeneity of β-thalassemia (β-thal) patients, several efforts have been undertaken to determine the efficacy of hydroxyurea treatment. The aim of this work is to determine the responder and nonresponder for hydroxyurea treatment in β-thal intermedia based on γ-globin mRNA and fetal hemoglobin (HbF) induction in human erythroid progenitor cells purified from a patient’s peripheral blood. Eighteen β-thal/hemoglobin E patients [13 β^E/codon41/42(-TCTT), 4 β^E/codon17, and 1 β^E/IVS-654], requiring blood transfusion occasionally, with Hb levels of 5.20–8.50 g/dl were studied. The relative levels of γ-globin mRNA was measured by real-time reverse-transcription polymerase chain reaction and HbF by high-performance liquid chromatography. The results indicated that erythroid progenitor cells treated with 30 μmol/l hydroxyurea for 96 h preferentially enhanced ^Gγ-and ^Aγ-globin mRNA. The mean values of ^Gγ-globin mRNA fold induction were higher than ^Aγ-globin mRNA (12±4 vs 4±0.30), the Pearson’s correlation of ^Gγ-and ^Aγ-globin mRNA was r=0.80. Induction of ^Gγ/^Aγ globin mRNA is up to ninefold. A 30% increase in the proportion of HbF out of the total Hb was found in cultures derived from four patients, 20–30% in cultures from nine patients, and less than 20% in cultures from five patients. In cultures from only two patients, increase in the proportion of HbF was less than 3%, and ^Gγ/^Aγ globin mRNA is less than 0.50.