A Phase 1 Study of FT819 in B-cell Mediated Autoimmune Disease

Key Who May Qualify: - Age: 12 to 70 years old. - Diagnosis: Must have active B-cell mediated autoimmune conditions (where your immune system attacks your own body) (SLE, AAV, IIM, or SSc) confirmed by standard criteria. - Disease Severity: Moderate to severe, requiring at least two prior treatments that were ineffective. - Health Status: your organs (liver, kidneys, etc.) are working well enough based on blood tests to tolerate treatment. - Consent: Able to provide willing to sign a consent form or assent/obtain parental consent and comply with study procedures. Key Who Should NOT Join This Trial: - Pregnancy/Breastfeeding: Women must not be pregnant or nursing. - Severe Organ Dysfunction: Significant heart, lung, liver, or kidney impairment. - Active Infections: No recent or ongoing serious infections. - Recent Cancer or Prior Cell Therapy: No active/recent malignancies, prior CAR T-cell therapy, or organ transplant. - Allergies: No known allergies to study treatments. - Weight Restriction: Must weigh at least 50 kg (110 lbs). Always talk to your doctor about whether this trial is right for you.