Recipient Inclusion Criteria:
* Age less than 22 years of age
* No available genotypically matched related donor (sibling)
* Availability of a suitable donor and graft source
* Haploidentical related mobilized peripheral blood cells
* 9/10 or 10/10 allele matched (HLA-A, -B, -C, -DRB1, -DQB1) volunteer unrelated donor mobilized peripheral blood cells
Donor Inclusion Criteria:
* Matching as described in the Recipient and Donor Suitability Criteria
* Size and vascular access appropriate by center standard for peripheral blood stem cell (PBSC) collection. Donors with inadequate peripheral access will require placement of an apheresis catheter for collection.
* Must meet appropriate screening/eligibility requirements:
* Haploidentical matched family members: screened by center health screens and found to be eligible.
* Unrelated donors: meet suitability criteria to donate PBSC
* HIV negative
* Not pregnant or lactating
* Recipient must not have high-level donor specific anti-HLA antibodies according to institutional practices.
* Must agree to donate PBSC
* Must give informed consent
Recipient Suitability:
\- Adequate organ functioning as demonstrated by:
* MUGA ≥ 50% or ECHO \>30%
* 24-hour Creatinine Clearance or Glofil ≥ 50 ml/min or Serum Creatinine ≤2 times the upper limit of normal
* DLCO \> 65% of predicted value. FEV1 \>65% of predicted
* AST / ALT ≤ 2.5 and/or Bilirubin ≤ 1.5 times the upper limit of normal
* Pregnancy test negative
* HIV 1 / 2 (HIV screen) negative with a negative qualitative HIV PCR.
* HTLV I negative
* RPR or VDRL negative
* RVP (Respiratory Viral PCR) with a negative result
* Positive hepatitis testing does not make the patient ineligible. Hepatitis results will be evaluated on a case-by-case basis by the transplant physician to determine donor suitability/eligibility.
Donor Suitability:
\- Allowed Donor Sources
* Fully matched sibling donors are not allowed.
* Unrelated donors. HLA typing of at least 10 alleles is required. Donor must be matched at 9/10 or 10/10 alleles (HLA-A, -B, -C, -DRB1, -DQB1). Haploidentical matched family members. Minimum match level full haploidentical (at least 5/10; HLA-A, -B, -C, -DRB1, -DQB1 alleles), but use of haploidentical donors with extra matches (e.g., 6, 7, or 8/10) encouraged.
* Cord blood is not allowed as a stem cell source on this IDE.
Recipient and Donor Exclusion Criteria:
* Pregnant or lactating females are ineligible as the risk to unborn children and infants is unknown
* Presence of life-threatening, uncontrolled opportunistic infection (fungal, bacterial, or viral infections). Patients with history of fungal disease during induction therapy may proceed if they have a significant response to antifungal therapy with no or minimal evidence of disease remaining by CT evaluation.
* HIV or HTLV I/II infection
