Effect of hydroxyurea on the transfusion requirements in patients with severe HbE-β-thalassaemia: a genotypic and phenotypic study

Background Haemoglobin E (HbE)-beta-thalassaemia has a very variable clinical presentation. The management of severe cases that are often transfusion dependent is similar to that of cases of beta-thalassaemia major; however, this is often not possible in India because of its high cost and the lack of availability of safe blood at many places. Thus there was a need for a drug such as hydroxyurea, which is known to reduce the transfusion requirements of patients with thalassaemia intermedia. This study was undertaken to evaluate the response of Indian patients with HbE-beta-thalassaemia to hydroxyurea. Materials and methods 11 patients with HbE-beta-thalassaemia receiving regular transfusion plus two less frequently transfused patients were selected for hydroxyurea therapy. Clinical and haematological evaluation was performed before and after treatment for 2 years. Molecular studies included beta-globin genotype, beta-globin gene haplotype, Xmn I polymorphism and alpha-genotyping. Results Four clinically severe patients became transfusion independent ( responders) after hydroxyurea therapy, four patients showed a reduction in their transfusion requirements ( partial responders), and three patients were non-responders. Responders showed a statistically significant increase in Hb, mean corpuscular volume, mean cell Hb, fetal Hb and F cells with a reduction in their transfusion requirements. A reduction in serum ferritin concentration was also seen in responders and non-responders. Conclusions Genetic markers such as Xmn I polymorphism and alpha-gene deletions were not always beneficial for the response to hydroxyurea therapy. Thus many more markers and a larger cohort need to be studied to predict the response in these patients.