FT839 in Autoimmune Diseases

Inclusion Criteria:

* Age ≥18 to ≤70 years
* Must have active B-cell mediated autoimmune disease (AAV, IIM, RA, SLE, or SSc) confirmed by standard criteria
* Moderate to severe disease, requiring at least two prior treatments that were ineffective
* Adequate organ function to tolerate treatment
* Able to provide informed consent and comply with study procedures

Exclusion Criteria:

* Diagnosis of more than 1 disease under study (AAV, IIM, RA, SSc, or SLE) or overlap syndrome
* Women must not be pregnant or nursing
* Severe Organ Dysfunction: Significant heart, lung, liver, or kidney impairment.
* Active or chronic infections
* Active or recent malignancies
* Prior CAR T-cell therapy or organ transplantation
* Known allergies to study treatments
* Body weight \<45 kg
* Active central nervous system (CNS) symptoms attributable to autoimmune disease or nonmalignant CNS disease within 12 months prior to trial intervention
* Receipt of any anti-CD19- or anti-CD20-directed therapy within 6 months prior to trial intervention