Study Investigating the Safety of Anti-CD19 CAR-T Cells Therapy Produced at Gustave Roussy for Adults With Severe and Refractory Systemic Autoimmune Rheumatic Diseases

Inclusion Criteria: * Adults aged 18-75 with ECOG PS 0-2 with written informed consent, valid health insurance, and eligibility for CAR T cell infusion are required may be included. Patients must have a treatment refractory systemic autoimmune rheumatic disease (RA, SLE, Sjögren's, SSc, or IIM) with severe, progressive activity with adequate renal function (creatinine clearance \> 30 mL/min) Exclusion Criteria: * Patients with any significant active infection, including hepatitis B or C, HIV, or other opportunistic or recurrent infections, are excluded. Prior gene therapy, previous CAR T treatment, active cancer within 2 years, or any history of allogeneic stem cell or solid organ transplantation exclude participation. Inadequate organ function-renal, hepatic, cardiac (LVEF \< 50%), or lung function requiring oxygen- and uncontrolled comorbidities prevents inclusion. Pregnancy, breastfeeding, or refusal to use highly effective contraception for 12 months post infusion