After demonstrating the in vitro cytotoxicity of BAFF CAAR T cells against B cells isolated from SLE patients, including CD19+ IgM+ cells, the authors assessed their therapeutic efficacy in vivo using three distinct SLE mouse models: the genetically predisposed spontaneous MRL/lpr model, pristane-induced SLE in BALB/c mice, and an SLE patient-derived xenograft (PDX) model, which involves injecting peripheral blood mononuclear cells (PBMCs) into immunocompromised NOD SCID gamma (NSG) mice [46]. The gene discussed is CD19; the disease is systemic lupus erythematosus.