CD19-BCMA Dual Nanobody Based CAR-T Cells for Patients With DSA

This is an early-stage, open-label clinical study of CD19-BCMA dual nanobody based CAR-T Cell desensitization therapy for patients positive for Donor-Specific Antibodies. Enrolled subjects will participate in an early clinical study using the traditional "3+3" dose escalation design to determine the Maximum Tolerated Dose (MTD) of CAR-T cell infusion (i.e., three escalating dose levels: 0.5x10\^6 CAR+ T cells/kg, 1x10\^6 CAR+ T cells/kg, 2x10\^6 CAR+ T cells/kg). The investigators and the sponsor will jointly form a Safety Review Committee (SRC). The final decision on whether to continue increasing the dose levels or to conduct an expansion study at a specific dose level will be based on the safety and efficacy data obtained from the three dose groups. Assessments will be performed every 4 weeks after cell infusion, with a total planned enrollment of 9-18 subjects.