Background
Thalassemia is the most common single gene inherited hematopoietic disorder[1]. In β-thalassemia, hemoglobin (Hb) production is insufficient because of mutations or deletions ofHBB gene, causing an imbalance between α-globin and β-globin. Complete deficiency of β-globin is regarded as β0 and partial β-globin deficiency is regarded as β+. According to the requirement of transfusion, β-thalassemia is classified into non-transfusion-dependent β-thalassemia (NTDT) (transfusions required under certain conditions such as infection, pregnancy or surgery) and transfusion-dependent β-thalassemia (TDT) (regular and lifelong transfusions required)[2]. Patients with β-hemoglobinopathies with higher fetal hemoglobin (HbF) level present with milder phenotypes than those with a lower HbF level.
Inducers of HbF, such as hydroxyurea and histone deacetylase inhibitors, are effective in improving hemoglobin level in some patients with β-thalassemia[3, 4].Thalidomide is an immunomodulatory agent with antiangiogenic properties. Clinical studies have demonstrated that thalidomide exerts promising effects on ameliorating anemia in patients with myeloproliferative disorders, sickle cell disease and β-thalassemia[4-7]. Previous studies have also shown that thalidomide is effective in some adult patients with β-thalassemia[7-9], but still not recommended to children for scarce evidence of safety and efficacy. Therefore, we performed this retrospective study to provide more evidence for the use of thalidomide in children with TDT β-thalassemia. Furthermore, we evaluated the potential predictors for response to thalidomide in children with TDT.