Clinical Study on the Treatment of Systemic Sclerosis With UTAA91 Injection.

Inclusion Criteria: * Aged ≥18 years (inclusive of the boundary value), with no restriction on gender. * Expected survival time of ≥3 months. * Refractory moderate - to - severe active systemic sclerosis that has failed standard treatment or lacks effective therapeutic options. * Meets the requirements for liver and kidney function, as well as cardiopulmonary function. * Free from severe psychiatric disorders. * Able to understand the trial and has signed the informed consent form. Exclusion Criteria: * A history of malignant tumors other than relapsed/refractory autoimmune diseases (R/R AID) within 5 years prior to screening. * Positive results in virology/syphilis tests. * Severe cardiac diseases or unstable systemic diseases. * Presence of active or uncontrollable infections requiring systemic treatment, or evidence of central nervous system invasion. * Pregnant or breastfeeding women, female subjects planning to become pregnant within 2 years after cell infusion, or male subjects whose partners plan to become pregnant within 2 years after their cell infusion. * Subjects who have received CAR - T therapy or other gene - modified cell therapies prior to screening. * Subjects who participated in other clinical studies within 1 month prior to screening. * Other conditions deemed unsuitable for enrollment by the investigator.