Assessment of Senl_B19 CAR-T Cells in Relapsed/Refractory CD19+ B-ALL

1.Relapse of isolated extramedullary disease; 2.Burkitt lymphoma/leukemia； 3.Active acute or moderate-to-severe chronic GVHD within 4 weeks prior to ICF signing. Or, any systemic GVHD treatment within 4 weeks prior to infusion; 4.No uncontrolled active infection at the time of ICF signing or apheresis.; 5.Prior receipt of any CAR-T therapy or other cellular/gene therapy before screening; 6.Received investigational drugs or systemic anti-tumor therapy within 4 weeks or 5 half-lives (whichever longer) prior to apheresis; 7.Active interstitial lung disease/pneumonitis at the time of ICF signing; 8.Subjects whom the Investigator considers unable to comply with the study protocol or who are otherwise not an appropriate candidate for the study for any reason;