Impact of β-globin mutations on outcome of matched related donor hematopoietic stem cell transplantation for patients with β-thalassemia major.

The clinical outcome of hematopoietic stem cell transplantation (HSCT) for patients with β-thalassemia major (β-TM) can be affected by several factors. We investigated the influence of β-globin gene mutation in patients with β-TM on the clinical outcome of HSCT and conducted a prospective study of consecutive β-TM patients who underwent allogeneic HSCT at our center. Among 87 included patients, 62 (71%) had homozygous and 25 (29%) had compound heterozygous β-globin gene mutations. Intervening sequence II-1 appeared to be the most common mutation, with an occurrence rate of 33% in β-globin alleles. With a median follow-up of 12 months, the thalassemia-free survival and overall survival probabilities were 83% (standard error, 4%) and 90% (standard error, 3%), respectively. Overall survival was not found to be associated with the β-globin gene mutation status, but thalassemia-free survival was significantly improved in patients with homozygous mutations compared with patients with compound heterozygous mutations in univariate (91.2% versus 64.0%, P = .009) and multivariable (hazard ratio, 3.83; P = .014) analyses. This is the first report on the impact of β-globin mutation status on the outcome of β-TM after allogeneic HSCT and helps to better illustrate the course and prognosis of β-TM after transplantation.