Hematopoietic Stem Cell Transplantation for Patients With Severe Sickle Cell Disease Using Myeloablative Conditioning and αβ+ T-cell Depleted Hematopoietic Stem Cells From Partially Matched Familial Donors

Hemoglobin SS, SC, S-β0 Thalassemia, or SO-Arab Sickle Cell Disease
Between the ages of 2 and 25 years (Stage 1: 10-25 years; Stage II: 2-25 years)
Lack a fully matched family donor or fully matched unrelated donor register in the National Marrow Donor Program
Partially-matched family member with hemoglobin AA (normal) or hemoglobin AS (sickle trait) phenotype
SCD with Severe Phenotype, defined by the following criteria: Neurologic manifestations of sickle disease including cerebral vascular accident (CVA), transient ischemic event (TIA) or abnormal MRI findings suggestive of silent infarct; Two or more episodes of acute chest syndrome (ACS) requiring admission for transfusional or respiratory support including supplemental oxygen within [two years] of enrollment in study despite hydroxyurea therapy. Patients who cannot tolerate hydroxyurea and who experience multiple episodes of ACS will also be eligible; History of severe vaso-occlusive (VOC) disease requiring hospitalization and intravenous narcotics on 3 or more occasions per year over the two years prior to enrollment despite hydroxyurea therapy. Patients who cannot tolerate hydroxyurea and who experience multiple episodes of VOC will also be eligible; Other severe phenotype as evidenced by end organ dysfunction related to sickle cell disease.