REACT-01: Reversing Autoimmunity Through Cell Therapy

Inclusion Criteria: * Male and female subjects aged between 2-30 years old. The first 3 subjects will be aged ≥ 17. The FDA will review safety data to determine if the age can be lowered first to ≥ 12 then, following the treatment of 3 further subjects aged 12-17, to ≥ 2 * Serologically active Systemic Lupus Erythematosus that is refractory to treatment * Able to tolerate apheresis or already has an apheresis product available for use in manufacturing. * ≥ 24 weeks post last Rituximab or related B cell depleting therapy * ≥ 12 weeks post last Belimumab / Anifrolumab therapy * ≥ 4 weeks post last calcineurin inhibitor treatment * For subjects receiving non-calcineurin immunosuppressive therapy, on a stable dose for ≥ 8 weeks before enrollment * For subjects receiving corticosteroid therapy, on a stable dose for ≥ 2 weeks before enrollment * Adequate organ function * Adequate laboratory values * Subjects of childbearing or child-fathering potential must agree to use highly effective contraception from consent through 12 months following infusion of investigational product on trial * Subjects must be willing to remain within 1 hour's drive of Seattle Children's Hospital for 4 weeks following CAR T cell infusion. * Subject and/or legally authorized representative has signed the informed consent form for this study Exclusion Criteria: * History or presence of active CNS lupus or other CNS disease * Kidney dysfunction requiring renal replacement therapy * Pregnant or breastfeeding * Insufficient pulmonary reserve including history of COPD, \>10 pack year smoking history or SLE lung disease with hypoxia at rest with oxygen saturation ≤92% on room air * Unable to tolerate repletion with any formulation of IgG. * Active or prior malignancy, unless the malignancy was treated and there is no evidence of recurrent disease \<5 years from enrollment. * Prior solid organ transplantation. * Presence of an active severe infection * Presence of any condition that, in the opinion of the investigator, would prohibit the subject from undergoing treatment under this protocol