Donor Characteristics Predict the Success of Allogeneic Hematopoietic Stem Cell Transplantation in Thalassemia Major: A Single-Center Analysis of 250 Patients.

We present data on the impact of donor characteristics in a uniform cohort of children who underwent hematopoietic stem cell transplantation (HSCT) for thalassemia major. We performed a retrospective study in children undergoing matched related (MRD) or unrelated (MUD) HSCT from January 2009 to December 2019. We analyzed data on 250 patients (age seven months-19 years), MRD n = 187, MUD n = 63. We documented sex mismatch in 44% of HSCTs. The graft rejection rate was 3.7%; all had a sex mismatched HSCT (P value = 0.001). Graft versus host disease (GVHD) was higher when donors were above two years as compared to less than two years (23%vs.6.5%, P value = 0.006), with higher rates of mixed chimerism when donors were < two years at 33.3%vs.8.3% in > two years (P value = 0.0001). Mortality and GVHD were higher in the MUD group as compared to the MRD group (15%vs.5%, P value = 0.009; 42.9%vs. 23.4%, P value = 0.0001 respectively). Overall survival was 92.8% with a median follow up of 5.4 years, and was superior in MRD versus MUD group (9.4 years versus 4.8 years P = 0.008). The risk of graft rejection was higher with donor-recipient sex mismatch; while initial mortality and chronic GVHD was higher with MUD HSCT.