[Allogeneic hematopoietic stem cell transplant in children and adults with sickle cell disease: Indications and modalities].

Sickle cell disease is associated with severe complications and early mortality in adults. In children, hematopoietic stem cell transplant from HLA-identical sibling can stop the progression of the disease and leads to more than 95% long-term free survival without sickle cell disease. The aim of this workshop was to define indications and modalities of allogeneic hematopoietic stem cell transplant in children and adults with sickle cell disease. Patient and sibling HLA typing should be proposed, early in the course of the disease, when intensification therapies are required. Indications of transplant from HLA-identical sibling in children and adults are, cerebral vasculopathy, occurrence of vaso-occlusive events despite hydroxycarbamide, renal and hepatic diseases related to SCD, chronic anemia<7g/dL despite hydroxycarbamide, need to maintain transfusion programs longer than six months, and major transfusion difficulties related to red blood cell alloimmunization. In children with an HLA-identical sibling donor, we recommend a myeloablative conditioning regimen associating high dose busulfan, cyclophosphamide and ATG, considering the excellent results of this approach In patients over 15 years of age, we recommend the NIH approach consisting of a reduced intensity conditioning regimen by alemtuzumab, and 3Gy total body irradiation, followed by peripheral hematopoietic stem cells and post-transplant immunosuppression by sirolimus In the absence of HLA-identical sibling donor, there is no definitive data for preferring transplant from unrelated versus haplo-identical donors but we recommend to evaluate these approaches in prospective trials.
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