CD45RA Depleted Peripheral Stem Cell Addback for Viral or Fungal Infections Post TCRαβ/CD19 Depleted HSCT

Inclusion Criteria:

1. Age: Patients \<25 years.
2. First allogeneic HSCT only.
3. Disease eligibility: Acute leukemias at high risk for relapse including positive minimal residual disease at end consolidation, high risk cytogenetics, or relapse. Hematologic malignancies including: acute myeloid leukemia, myelodysplastic syndromes, acute lymphoblastic leukemia, mixed lineage or bi-phenotypic leukemia, lymphoblastic or Burkitts, juvenile myelomonocytic leukemia
4. Evaluation of organ and infectious status as per our Bone Marrow Transplant standard operating procedure (BMT SOP).
5. Signed consent by parent/guardian or able to give consent if \>18 years.

Exclusion Criteria:

1. Patients who do not meet institutional disease, organ or infectious criteria
2. No suitable donor available for mobilized peripheral stem cells
3. Patients with genetic disorders including Fanconi anemia, Kostmann syndrome, dyskeratosis congenital or other DNA repair defects.
4. Patients with Hodgkin lymphoma or non-Burkitts, non-lymphoblastic lymphoma
5. Pregnant Participants

Donor selection and eligibility

1. Unrelated donor meets National Marrow Donor Program criteria for donation
2. HLA testing/matching
3. Donor must be willing to undergo granulocyte colony stimulating factor (GCSF) mobilization and peripheral blood stem cell collection