RecruitingPhase 1Biological interventionCD45BE-HSPC + CART-45 CellsThis is a phase 1, open-label, dose-finding study to assess the safety, feasibility, pharmacokinetics and preliminary efficacy of autologous base edited anti-CD45 CAR T cells (referred to as "CART-45 cells") following an autologous transplant of CD45 base edited hematopoietic stem and progenitor cells (referred to as "CD45BE-HSPC") in patients with relapsed or refractory hematologic malignancies.