Severe sickle cell disease [Hemoglobin SS (Hb SS), Hemoglobin SC (Hb SC) or Hemoglobin SBeta thalassemia (Hb S?) genotype] with at least 1 of the following manifestations (a-e): Hemoglobin (Hb) > 9 g/dL within 3 weeks prior to study registration Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) greater than or equal to 9.0 g/dL Hemoglobin (Hb) concentration < 8.0 g/dL Adequate bone marrow function (hemoglobin [Hb] ? 9.0 g/dL [subjects may be transfused to Hb ? 9.0 g/dL]; platelets ? 100 × 109cells/L; absolute neutrophil count [ANC] ? 1.5 × 109 cells/L without the use of hematopoietic growth factors). Hemoglobin (Hb) >= 9 g/dL Hemoglobin (Hb) value > 9 g/dL Hb <70 g/L (<7.0 g/dl) and/or transfusion dependency Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) > 8.0 g/dL Hemoglobin (Hb) >= 9 g/dL Hemoglobin (Hb) ? 9 Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) at least 8.0 grams per deciliter (g/dL) at baseline (blood transfusions are allowed during the screening period to correct Hb values less than 8.0 g/dL). Hemoglobin (Hb) at least 9 g/dL (or 5.69 mmol/L) at baseline (blood transfusions, hematopoietic growth factors and hematinics are not allowed during the 7 days prior to screening to correct Hb values less than 9 g/dL) Hemoglobin (Hb) > 9 g/dl Hemoglobin (Hb) < 8.0 g/dL Hemoglobin (Hb) >= 9.0 g/dL (For both cohorts A and B): Hemoglobin (Hb) > 9 G/dL Hemoglobin (Hb) ?5.5 and ?10.5 g/dL during screening Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) > 9.0 g/dL within 7 days prior to enrollment; Note: the use of transfusion or other intervention to achieve Hb >= 9.0 g/dL is acceptable Hemoglobin (Hb) > 9 g/dl Hemoglobin (Hb) level < 8 gm/dl Hemoglobin (Hb) ? 9 g/dL Hemoglobin (Hb) >= 9 g/dL Hemoglobin (Hb) < 8 g/dL Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) ? 10 g/dL Hemoglobin (Hb) >= 6.0 mmol/L Hemoglobin (Hb) level < 9 g/dL Hemoglobin (Hb) >= 9.0 g/dL (transfusion independent) Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) >= 9.0 g/dL Hemoglobin (Hb) > 9 g/dL Eligible diagnoses: patients with sickle cell anemia such as sickle cell anemia (hemoglobin [Hb] SS), Hb S/ beta° thalassemia, Hb S/beta positive (+) thalassemia, Hb SC disease, Hb SE disease, Hb SD disease, Hemoglobin SO-Arab disease Hb S/hereditary persistence of fetal hemoglobin; other significant hemoglobinopathies that also fulfills a criterion from below Hemoglobin (Hb) ? 9 g/dL Hemoglobin (Hb) >= 9 g/dL Hemoglobin (Hb) >= 9 g/dl Hemoglobin (Hb) >= 9 g/dL Hemoglobin (Hb) > 8.0 g/dL Hemoglobin (Hb) at least 8 g/dL at baseline (blood transfusions are allowed during the screening period to correct Hb values less than 8 g/dL) Hemoglobin (Hb) >= 9 g/dL Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) >= 9.0 g/dl DONOR: Anemia (hemoglobin [Hb] < 11 gm/dl) or thrombocytopenia (< 100,000/ul) Polycythemia Vera (2 major criteria required)\r\n* Hemoglobin (Hb) > 18.5g/dl (male) or 16.5g/dl (female) or \r\n* Hematocrit (HCT) > 99 percentile reference range or \r\n* Elevated red cell mass (> 25% above mean predicted value) or \r\n* Hb > 17g/dl (male) or 15g/dl (female) if associated with a sustained rise from baseline with no apparent cause (e.g. treated iron deficiency)\r\n* Presence of JAK2V617F Hemoglobin (Hb) >= 9 g/dl for males and >= 8 g/dl for females Hemoglobin (Hb) <9 g/dL (90g/L) Hemoglobin (Hb) greater than or equal to 8.5 g/dL Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) > 9 gm/l Prior to cyclophosphamide and T cell infusions: hematocrit (Hct) =< 24% or hemoglobin (Hb) =< 8 g/dL Hemoglobin (Hb) > 10 g/dl Hemoglobin (Hb) > 9.0 g/dL within 7 days prior to enrollment; note: the use of transfusion or other intervention to achieve Hb >= 9 g/dL is acceptable (within 7 days prior to registration) Hemoglobin (Hb) >= 9 g/dL without transfusion for 3 weeks Hemoglobin (Hb) < 8 g/dL Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) >= 9 g/dL Hematocrit (Hct) =< 24% or hemoglobin (Hb) =< 8 g/dL Hb level ?9 g/dL Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) greater than or equal 8.5 g/dL Hemoglobin (Hb) >= 8 g/dl Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) >= 9 mg/dl Hemoglobin (Hb) > 9g/dL MATCHED RELATED DONOR: Anemia (hemoglobin [Hb] < 10 gm/dl) or thrombocytopenia (< 100,000/ul) Hemoglobin (Hb) at least 9 g/dL (or 5.69 mmol/L) at baseline (blood transfusions, hematopoietic growth factors and hematinics are not allowed during the 7 days prior to screening to correct Hb values less than 9 g/dL) Anemia (hemoglobin [Hb] < 10 g/L) Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) >= 9 g/dL Hemoglobin (Hb) >= 9 g/dL Hemoglobin (Hb) < 8 g/dL Hemoglobin (Hb) ? 9 g/dL Platelets ? 100 x 10^9, Hb ? 90 g/L, ANC ? 1.5 x 10^9/L. Hemoglobin (Hb) level < 9 gm/dl Hemoglobin (Hb) > 8 gr/dL not supported by transfusions Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) greater than or equal to 10g/dL at baseline (blood transfusions,hematopoietic growth factors and hematinics are allowed during the Prerandomization Phase to correct Hb values less than 10g/dL). Hemoglobin (Hb) >= 9 g/dL Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) 9 >= g/dl Hemoglobin (Hb) > 9 g/dL Hemoglobin (Hb) > 8 g/dL Hemoglobin (Hb) > 9 g/dL