BCMA-CD19 CAR-T Therapy for Refractory Autoimmune Diseases

The investigators designed a single-center, open-label, single-arm clinical study. Adults with multiple refractory autoimmune diseases will be enrolled, meeting the inclusion criteria. BCMA-CD19 targeted chimeric antigen receptor T-cells will be administered intravenously 1-2 days after preconditioning, at a dose of 3×10\^6/kg of CAR-T cells per kilogram (referring to successfully transduced CAR-T cells, not total T cells). The total volume of the CAR-T cell suspension administered per patient will range from approximately 10 to 70 mL, using a "single-dose" regimen. The entire dose of CAR-T cells will be infused intravenously rapidly on day 0. Patients will be evaluated for improvements in clinical and laboratory parameters to assess the safety and efficacy of BCMA-CD19 CAR-T therapy. The primary endpoints include the Complete Remission Rate and laboratory indicators. Secondary endpoints include pharmacokinetic characteristics, long-term efficacy, and safety.