Hematopoietic Cell Transplantation/HCT involves receiving healthy blood-forming cells (stem cells) from a donor to replace the diseased or damaged cells in participants' bone marrow. The researchers think giving participants treatment with fludarabine and dexamethasone, drugs that lower the activity of the body's immune system (immune suppression), before standard conditioning therapy and HCT may help prevent serious side effects, including graft failure and GvHD. In this study, depending on how participants' body responds to the fludarabine and dexamethasone, the study doctor may decide participants should receive another drug, called cyclophosphamide, instead of fludarabine. In addition, depending on the results of participants' routine blood tests, participants may receive the drugs bortezomib and rituximab, which also help with immune suppression.
Age ≥ 2 and ≤ 50 years
Suitable haploidentical donor.
Performance score ≥ 70% by Karnofsky Performance Scale or 0 to 1 by ECOG (age > 16 years), or Lansky Play-Performance Scale ≥ 70% (age ≤ 16 years).
eGFR ≥ 50 mL/min by Cockcroft-Gault formula Formula: ((140 - Age) x Weight (kg)) / (72 x Serum Creatinine (mg/dL) Female Adjustment: Multiply result by 0.85
Prior myeloablative allogeneic HCT.
Overt stroke or CNS instrumentation (e.g. for Moyamoya disease) within 6 months of enrollment.
Liver cirrhosis. Mild fibrosis will be permitted, i.e. fine reticulin or grade 1 of 4, with bridging fibrosis.
Hepatic iron content ≥ 3 mg Fe/g liver dry weight, if applicable