The purpose of this study is to learn more about newer methods of transplanting blood cells donated by a partially matched family member to children with high-risk CD19 positive leukemia ALL.
Primary Objective:
\- To assess the safety and feasibility of combining CD19-CAR(Mem) T cells after TCRαβ+/CD19 depleted haploidentical donor transplantation for pediatric patients with relapsed/refractory CD19+ B-cell malignancies.
Secondary Objectives:
* To estimate 1-year post-transplant overall survival, event-free survival, and GVHD-free relapse-free survival (GRFS). * To estimate cumulative incidence of engraftment, acute and chronic GVHD, and immune-related adverse events, including CRS and ICANS.
Age less than or equal to 21 years
High risk CD19+ B cell ALL in CR1 or CR2
Any CD19+ B-cell ALL in CR3 or subsequent
If prior CNS leukemia, it must be treated and in CNS CR
Has a suitable HLA-identical sibling or suitable 12/12 (HLA-A, B, C, DRB1, DQB1, and DPB1) HLA-matched unrelated donor available in an appropriate time frame
Any other active malignancy other than the one for which this HCT is indicated
Received a prior allogeneic HCT at any time
Pregnant, if female is of childbearing potential, negative test must be confirmed by serum or urine pregnancy test within 14 days prior to enrollment