Azathioprine/hydroxyurea preconditioning prior to nonmyeloablative matched sibling donor hematopoietic stem cell transplantation in adults with sickle cell disease: A prospective observational cohort study.

Nonmyeloablative, matched sibling donor hematopoietic stem cell transplantation with alemtuzumab/total body irradiation (TBI) conditioning is a curative therapy with low toxicity for adults with sickle cell disease (SCD). However, relatively low donor chimerism levels and graft rejection remain important challenges. We hypothesized that adding azathioprine/hydroxyurea preconditioning will improve donor chimerism levels and reduce graft failure rate.