Switch from beta-thalassemia major to beta-thalassemia intermedia after secondary graft failure

In this article, we report a switch of beta-thalassemia major to intermedia beta-thalassemia after allogeneic bone marrow transplant of a 6-year-old girl from her HLA-matched brother. After stable mixed chimerism, the patient had a secondary graft rejection and returned to total recipient chimerism as assessed by real-time polymerase chain reaction assay. Nonetheless, with a medium hemoglobin rate of 89 g/L, she did not need further transfusions for 60 months after rejection. We conclude that complete loss of donor cells after bone marrow transplant for beta-thalassemia major is compatible with a stable clinical state, probably due to a gamma-globin gene demethylation that enhances gamma-globin chain production and further allows constitution of a fetal hemoglobin rate compatible with free transfusion survival.