Nevertheless, the immune evasion phenomenon is frequently observed in other current ACTs that show clinical efficacy, such as the B-ALL escape from CD19 CAR-T cells via CD19 downregulation44, or the HLA loss that occurs in acute leukemia relapse resulting from allogeneic T cell immune pressure after allogeneic hematopoietic cell transplantation45. This evidence concerns the gene CD19 and acute leukemia.