study evaluates a biomarker-guided strategy to assign adults with refractory SLE to autologous CAR-T therapy targeting either CD19 or BCMA. Participants undergo centralized screening immunophenotyping to determine whether their disease appears B-cell-dominant (CD19-preferred) or plasma-cell-dominant (BCMA-preferred), followed by leukapheresis, lymphodepletion, and a single CAR-T infusion. The main goals are to assess safety, determine a recommended Phase 2 dose within each arm, and estimate remission rates by Week 24.