TCRαβ-depleted Progenitor Cell Graft With Additional Memory T-cell DLI, Plus Selected Use of Blinatumomab, in Naive T-cell Depleted Haploidentical Donor Hematopoietc Cell Transplantation for Hematologic Malignancies

Patients less than or equal to 21 years old with high-risk hematologic malignancies who would likely benefit from allogeneic hematopoietic cell transplantation (HCT). Patients with a suitable HLA matched sibling or unrelated donor identified will be eligible for participation ONLY if the donor is not available in the necessary time. The purpose of the study is to learn more about the effects (good and bad) of transplanting blood cells donated by a family member, and that have been modified in a laboratory to remove the type of T cells known to cause graft-vs.-host disease, to children and young adults with a high risk cancer that is in remission but is at high risk of relapse. This study will give donor cells that have been TCRαβ-depleted. The TCR (T-cell receptor) is a molecule that is found only on T cells. These T-cell receptors are made up of two proteins that are linked together. About 95% of all T-cells have a TCR that is composed of an alpha protein linked to a beta protein, and these will be removed. This leaves only the T cells that have a TCR made up of a gamma protein linked to a delta protein. This donor cell infusion will be followed by an additional infusion of donor memory cells (CD45RA-depleted) after donor cell engraftment. This study will be testing the safety and effects of the chemotherapy and the donor blood cell infusions on the transplant recipient's disease and overall survival.