• Participants must personally sign an informed consent form approved by the Ethics Committee before the start of the study.

• Participants must be aged ≥18 and ≤65 years.

• Disease-specific inclusion criteria:

• Active, relapsing, refractory Lupus Nephritis (LN):

• LN diagnosed by kidney biopsy within the last 2 years, with pathological types III, IV, or V, and a chronicity index (CI) score≤3

• Meets one of the following criteria:

• Refractory LN, defined as no remission after at least one standard regimen (CTX and/or MMF) for 6 months.

• Relapsing LN, defined as a need to increase steroid dosage to control disease activity during maintenance treatment.

• Clinical criteria: eGFR \> 45 ml/min/1.73 m²; urinary protein quantification ≥ 1.5g/24h; SLE-DAI score ≥ 8.

• ANCA-associated vasculitis (AAV) patients:

• Diagnosed as AAV according to the 2012 Chapel Hill Consensus Conference criteria, meeting one of the following:

• Newly diagnosed AAV with renal involvement:

• Renal involvement must meet both:

• Kidney biopsy showing pauci-immune necrotizing glomerulonephritis. Urinary red blood cells \>30/high power field.

• Relapsing or refractory AAV:

• Relapse: Defined as an increase in BVAS V3.0 score of ≥1 after remission, requiring adjustment of immunosuppressive treatment to regain remission.

• Refractory: Defined as a) less than 50% reduction in BVAS V3.0 after 6 weeks of standard induction treatment; or b) persistent disease activity (BVAS V3.0 ≥3) after 12 weeks of treatment.

• Membranous nephropathy (MN) patients:

• Tissue biopsy diagnosed as aPLA2R-related membranous nephropathy.

• Clinical criteria for high-risk or relapsing/refractory membranous nephropathy:

• High-risk patients:

• Defined as meeting any of the following: eGFR normal, urinary protein \>3.5g/d, ACEI/ARB treatment for 6 months with \<50% reduction in urinary protein, combined with serum albumin \<25g/l or aPLA2R \>50RU/ml; or eGFR \<60ml/min/1.73m², and/or urinary protein \>8g/d for over 6 months.

• Refractory/relapsing membranous nephropathy patients:

• Refractory: Defined as resistance to previous immunosuppressive treatment (persistent urinary protein ≥3.5g/d with \<50% reduction compared to baseline).

• Relapse: Defined as complete or partial remission achieved with previous immunosuppressive treatment, followed by reappearance of urinary protein ≥3.5g/d.

• eGFR ≥ 45 ml/min/1.73 m².

• IgG4-related disease patients:

• Meeting the 2019 ACR/EULAR diagnostic criteria for IgG4-related disease, and meeting one of the following:

• Newly diagnosed active IgG4-related disease (Respond Index (RI) ≥3).

• Refractory or relapsed IgG4-related disease:

• Refractory: Defined as no remission with steroid or steroid plus immunosuppressant treatment (no clinical or imaging improvement, RI decrease \<2) Relapse: Defined as new progression or recurrence of clinical symptoms or imaging findings in a patient who had achieved remission, with or without elevated blood IgG4 (RI increase≥2)

• Expected survival ≥ 12 weeks.

• ECOG performance status ≤ 2.

• Female participants of childbearing potential must agree to use effective contraception from the day of signing the informed consent until 365 days after the infusion. Effective contraception is defined as abstinence or the use of a contraceptive method with a failure rate of \<1% per year.

• Participants must have adequate organ function, meeting all of the following criteria before enrollment:

‣ Absolute neutrophil count ≥ 1.0×10⁹/L \[Granulocyte colony-stimulating factor (G-CSF) support is allowed, but no supportive treatment should be received within 7 days before the assessment\].

⁃ Platelet count ≥ 50×10⁹/L \[No transfusion support (including component transfusion) or treatments aimed