Hematopoietic stem cell transplantation for adult sickle cell disease in the era of universal donor availibility

Abstract

Current projections estimate that the number of newborns with sickle cell disease (SCD) globally will exceed 400,000 by 2050. Over the last three decades, increased newborn screening, supportive care, and use of hydroxyurea therapy, have decreased early childhood mortality among individuals affected with SCD. Despite hematopoietic cell transplantation (HCT) being curative in SCD, its impact on disease free survival remains unknown, especially in adults, partly due to previous limitations in donor options and perceived mortality in adults using myeloablative conditioning. Novel non-myeloablative or reduced intensity conditioning regimens have made HCT safer and applicable to adults with SCD who were previously excluded. Other reasons for limited use of HCT in SCD includes referral bias, provider preference, poor education of patient/families, perceived procedure risks, costs and limited logistic resources in both low income, middle income, and high income countries. Current data from landmark studies indicate that both the long-term disease-free survival and overall survival exceed 90% after matched sibling donor HCT in children. Improving transplant outcomes and expanding donor pool will increase the use of transplant for SCD, especially in affected adults. On-going investigations using matched umbilical cord units, unrelated matched donor, and related haploidentical donors, promises to make HCT a viable option for nearly all eligible patients with SCD. This systematic review focuses on the recent data for HCT for patients with adult SCD with particular emphasis on donor sources and availability as illustrated by a case presentation exhibiting real world issues.