RecruitingEarly Phase 1Biological interventionExploratory Clinical Study on the Safety and Efficacy of Anti- CD19/BCMA U CAR-T Cell Injection for the Treatment of Relapsed/Refractory Autoimmune DiseasesA single arm, open-label pilot study is designed to determine the safety and effectiveness of anti-CD19/BCMA U CAR T cells in patients with autoimmune diseases. 60 patients are planned to be enrolled in the dose-escalation trial.