Preventive infusion of donor-derived CAR-T cells after haploidentical transplantation Two cases report

Abstract

Rationale: Relapse is the main cause of death after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Unfortunately, there are no efficient methods to prevent relapse after allo-HSCT. Chimeric antigen receptor T (CAR-T) cells have achieved favorable outcomes in the treatment of refractory/relapsed acute lymphoblastic leukemia (ALL) because of their strong anti-leukemia activity. However, it is unclear whether the CAR-T cells constructed using viral systems can be used as preventive infusions to prevent relapse after haploidentical HSCT. Patient concerns: Two patients with ALL with high risk received haploidentical HSCT. Diagnoses: Two patients were diagnosed with ALL with high risk. Interventions: Patients received preventive infusion of donor-derived CAR-T cells constructed using viral systems on day 60 after haploidentical HSCT. Outcomes: The CAR-T cells were continually detected, and no graft versus host disease developed. The two patients survived with disease-free for 1 year and 6 months, respectively. Lessons: Preventive infusion of donor-derived CAR-T cells after haploidentical HSCT may be safe and that immunosuppressors may not affect the proliferation of CAR-T cells. Abbreviations: ALL = acute lymphoblastic leukaemia, allo-HSCT = allogeneic hematopoietic stem cell transplantation, CAR-T cells = chimeric antigen receptor T cells, CRS = cytokine release syndrome, DLI = donor lymphocyte transfusion, GVHD = graftversus- host disease, GVL = graft-versus-leukemia, Hyper-CVAD = cyclophosphamide, vincristine, doxorubicin, and dexamethasone.