In this prospective study of 30 patients with severe sickle cell disease (SCD), a novel non-myeloablative conditioning regimen prior to HCT was shown to reduce regimen-related toxicity and result in stable long-term donor mixed T-cell chimerism. Thirty patients aged 16-65 years were enrolled and received low-dose alemtuzumab and total-body irradiation, with sirolimus as GVHD prophylaxis. At a median of 3.4 years (range, 1-8.6), 29 patients were alive, and 15 engrafted patients discontinued immunosuppression with continued stable donor chimerism and no GVHD. The mean annual hospitalization rate of 3.23 prior to HCT declined each year of the study down to 0.11 at year 3 (p<0.05). The mean weekly narcotics dose dropped from 639 mg at the time of HCT to 140 mg per week 6 months after HCT.
Related editorial: Reconsideration of age as a contraindication for HCT in SCD