A Study on the Effect of MRD Detected by FAPI PET / CT on the Recurrence of IgG4-RD

Inclusion Criteria: 1. age 18-75 years old ; 2. Meet the 2019 ACR / EURLAR IgG4-RD diagnostic criteria ; 3. The disease was stable for more than 1 year, and the clinical evaluation of the disease was complete remission \* ; 4. Glucocorticoid dosage ≤ prednisone 7.5mg / d × 6 months or more, or combined with an immunosuppressive therapy ( mycophenolate mofetil ) Ester ≤ 1.0g / d, leflunomide ≤ 20mg / d, methotrexate ≤ 15mg / w, azathioprine ≤ 100mg / d, iguratimod ≤ 25mg Bid ) Exclusion Criteria: ( 1 ) Combined with other connective tissue disease patients ( 2 ) patients with tumor ; ( 3 ) women during pregnancy or planning pregnancy ; ( 4 ) active infection, including HIV, HCV, HBV, TB, etc. ; ( 5 ) Severe irreversible organ damage ; ( 6 ) In the active stage of the disease, the IgG4-RD reaction index score of the single affected organ was 2 points ; ( 7 ) stable condition less than 1 year ; ( 8 ) patients who relapsed within 1 year of previous hormone reduction and withdrawal ; ( 9 ) Combination of two or more immunosuppressive agents.