Effect of hydroxyurea on the transfusion requirements in patients with severe HbE-beta-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.

Response to hydroxyurea in beta thalassemia major and intermedia: experience in western India.

BACKGROUND: The clinical and hematological response to hydroxyurea was evaluated in beta thalassemia patients in western India with variable clinical severity and correlated with genetic factors. MATERIALS AND METHODS: Seventy-nine patients-[38-beta thalassemia intermedia-(group I), 41-beta thalassemia major-(group II)] on hydroxyurea therapy were followed-up for 20-24months. RESULTS: Among the frequently transfused patients in group I, 58% became transfusion independent and 16% showed a 50% reduction in transfusions after therapy which correlated with a higher mean fold increase in HbF and gamma mRNA expression levels. Forty-one percent of patients in group I had associated alpha-thalassemia and 72.7% were XmnI (+/+). beta thalassemia chromosomes among the responders of group I (41%) were linked to haplotype (- + + - + + - - +) as against haplotype (+ - - - - - - - +) being more common among the non-responders. Response was not linked to the beta thalassemia mutations. Thirty-two percent of group II patients showed a 50% reduction in their transfusion requirements after therapy which also correlated with a higher mean fold increase in HbF and gamma mRNA expression levels. A significant decrease in serum ferritin was seen in both groups. 19% of patients could not tolerate the drug. CONCLUSIONS: In group I, clinical response to hydroxyurea was better in patients with alpha-thalassemia, XmnI (+/+) and a higher mean fold increase in gamma mRNA expression. In group II, only one-third of patients showed a partial response.