Ph I/II Study of Allogeneic SCT for Clinically Aggressive Sickle Cell Disease (SCD)

Inclusion Criteria: * Patients with sickle cell disease, subtype Hgb SS, SC, or SB disease who are on chronic transfusion therapy for a prior stroke or those patients who were intolerant of hydroxyurea therapy or were being treated with hydroxyurea therapy and were complicated by at least one of the following: * Stroke or central nervous system event lasting longer than 24 hours * Frequent vaso-occlusive pain episodes, defined as ≥ 3 per year severe enough to interfere with the patient's normal daily function or require medical attention in the clinic, emergency room, acute care center, or hospital * Recurrent episodes of priapism, defined as ≥ 2 per year requiring emergency room visits * Acute chest syndrome with recurrent hospitalizations, defined as ≥ 2 lifetime events * Red-cell alloimmunization (≥ 2 antibodies) during longterm transfusion therapy * Bilateral proliferative retinopathy with major visual impairment in at least one eye * Osteonecrosis of 2 or more joints * Sickle cell nephropathy * Stage I or II sickle lung disease * Symptoms of pulmonary hypertension and mean pulmonary artery pressure \> 25mmHg * Age 16-60 years * Karnofsky performance status of 70 or higher * Adequate cardiac function, defined as left ventricular ejection fraction ≥ 40% * Adequate pulmonary function, defined as diffusion lung capacity of carbon monoxide ≥ 50% * Estimated GFR ≥ 30mL/min as calculated by the modified MDRD equation * ALT ≤ 3x upper limit of normal * No e…