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

Abstract

Due to genetic heterogeneity of beta-thalassemia (beta-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 beta-thal intermedia based on gamma-globin mRNA and fetal hemoglobin (HbF) induction in human erythroid progenitor cells purified from a patient's peripheral blood. Eighteen beta-thal/hemoglobin E patients [13 beta(E)/codon41/42(-TCTT), 4 beta(E)/codon17, and 1 beta(E)/IVS-654], requiring blood transfusion occasionally, with Hb levels of 5.20-8.50 g/dl were studied. The relative levels of gamma-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 mumol/l hydroxyurea for 96 h preferentially enhanced (G)gamma-and (A)gamma-globin mRNA. The mean values of (G)gamma-globin mRNA fold induction were higher than (A)gamma-globin mRNA (12+/-4 vs 4+/-0.30), the Pearson's correlation of (G)gamma-and (A)gamma-globin mRNA was r=0.80. Induction of (G)gamma/(A)gamma 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 (G)gamma/(A)gamma globin mRNA is less than 0.50.