Mixed chimerism following hematopoietic stem cell transplantation in pediatric thalassemia major patients: a single center experience.

ABSTRACT

OBJECTIVE: Stable mixed chimerism (MC) may result in cure for thalassemia major patients following hematopoietic stem cell transplantation (HSCT), but rejection can occur. Twenty-eight HSCTs for thalassemia major were reviewed retrospectively to evaluate the clinical course of MC with possible risk factors and predictors of outcome, with a median follow-up of 1669 days (811-3576 days). METHODS: Chimerism was detected by fluorescence in situ hybridization (FISH) or multiplex polymerase chain reaction depending on the sex match between the donor and the recipient. RESULTS: Primary rejection, stable MC and full donor chimerism was detected in 3.6%, 17.8% and 78.6% of patients, respectively. Clinically, 4/5 patients with stable MC had thalassemia trait with donor chimerism as low as 14%. One patient was started on pRBC transfusions at 2.5 years postHSCT. CONCLUSION: Stable MC can result in cure for thalassemia major patients. The clinical picture remains as the best guide for intervention until a more reliable predictor is available.