Sustained donor engraftment after allogeneic hematopoietic cell transplantation (HCT) converts to healthy donor hemoglobin synthesis and halts disease symptoms in patients with sickle cell disease and thalassemia major. A disease-free survival probability that exceeds 90% has been reported when HCT using an HLA-matched sibling donor is performed in young patients with low-risk disease or treatment-related risk factors. Alternate donor HCT and HCT in adults is performed infrequently because of a higher risk profile. Transplant-specific risks include conditioning regimen-related toxicity, graft-versus-host disease, graft rejection with marrow aplasia or disease recurrence, and infections associated with immunosuppression and delayed immune reconstitution. The magnitude of risk depends on patient age, clinical status of the underlying disease (eg, organ injury from vasculopathy and iron overload), donor source, and intensity of the conditioning regimen. These risks are commonly monitored and reported in the short term. Documenting very late outcomes is important, but these data are rarely reported because of challenges imposed by patient drop-out and insufficient resources. This report summarizes long-term follow-up results after HCT for hemoglobin disorders, identifies gaps in knowledge, and discusses opportunities for future investigations. This consensus summary will be followed by a second article detailing comprehensive long-term follow-up recommendations to aid in maintaining health in these individuals and identifying late complication risks that could facilitate interventions to improve outcomes.
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Financial disclosure: This work was supported in part by grants from the Children's Discovery Institute of Washington University and St. Louis Children's Hospital (grant no. MC-II-2016-524 to S.S.), the National Heart, Lung, and Blood Institute and National Cancer Institute (U10-HL069294) to the Blood and Marrow Transplant Clinical Trials Network, National Marrow Donor Program, Sickle Cell Disease Clinical Research Network, National Center on Minority Health and Health Disparities, Robert Wood Johnson Foundation Harold Amos Medical Faculty Development Program award (to S.D.A.), the Pediatric Blood and Marrow Transplant Consortium, National Institutes of Health 1R13CA159788-01 (to M.A.P. and K.S.B.), and RO1 CA07893 (to K.S.B.).
© 2017 The American Society for Blood and Marrow Transplantation
- Late effects
- Pediatric stem cell transplant
- Sickle cell disease