This is a prospective, single-arm, open-label and dose-escalation investigator initialed study to evaluate LUCAR-G79D in adult subjects with r/r SLE and r/r IIM.

This is a prospective, single-arm, open-label clinical study to evaluate the safety, tolerability, pharmacokinetics and efficacy profiles of LUCAR-G79D, a chimeric antigen receptor (CAR) -T cell therapy in subjects with r/r SLE and r/r IIM. Patients who meet the eligibility criteria will receive LUCAR-G79D infusion. The study will include the following sequential stages: screening, pre-treatment (lymphodepleting chemotherapy), treatment (LUCAR-G79D infusion) and follow-up.

Inclusion Criteria:

1. Subjects voluntary agreement to provide written informed consent.
2. Aged 18 to 70 years, either sex.
3. Adequate organ function meet screening criteria.
4. Positive test for cluster of differentiation antigen 19 (CD19).

SLE:

• Have been diagnosed of SLE at least 6 months before screening.
• At screening, antinuclear antibody, and/or anti-dsDNA antibody, and/or anti-Smith antibody should be positive.
• Fulfill relapsed/refractory SLE conditions.

IIM:

• Have been diagnosed of IIM before screening.
• Positive test for myositis-associated antibodies or myositis-specific antibodies at screening.
• Fulfill relapsed/refractory IIM conditions.

Exclusion Criteria:

1. Active infections such as hepatitis and tuberculosis.
2. Other autoimmune diseases.
3. Serious underlying diseases such as tumor, uncontrolled diabetes.
4. Female subjects who were pregnant, breastfeeding.
5. Those with a history of major organ transplantation.