Indications and Results of HLA-Identical Sibling Hematopoietic Cell Transplantation for Sickle Cell Disease

Abstract

Although a number of published trials exist of HLA-identical sibling hematopoietic cell transplantation (HCT) for sickle cell disease (SCD) that span 2 decades, when and for whom this therapy should be pursued is a subject of debate. Assessments of the risks of transplant-related complications that include infertility and debilitating graft-versus-host disease and long-term quality of life after successful HCT are difficult to perform without prospective trials in transplant and nontransplant cohorts. However, it is possible to assess the risk of mortality and to compare published rates of survival in individuals with SCD treated and not treated by HCT. In this brief review, projections about mortality risk based on recent published reports are reviewed and summarized. The published data show overall survival and event-free survival rates of 95% and 92%, respectively, in children treated by HLA-identical sibling HCT. The overall survival rates in the Center for International Blood and Marrow Transplant Research (N = 412) and European Blood and Marrow Transplant (N = 487) registries were 91% and 95%, respectively. These results provide broad support for the therapeutic value of HLA-identical sibling HCT for children with SCD and serve as the basis for a strong recommendation in favor of the option of HCT when a suitable donor is available. The experience of HLA-identical sibling HCT in adults with SCD is limited but appears to be similar to results in children. These preliminary observations, however, warrant further investigation.