This study has been designed as a 12-month, open-label randomized controlled clinical trial. The study aims to compare the efficacy and safety of two treatment strategies in IgG4-RD patients with superficial organ involvement: prednisone plus iguratimod and prednisone plus leflunomide.
1. Fulfillment of the 2019 American College of Rheumatology/European League against Rheumatology (ACR/EULAR) IgG4-related disease classification criteria; 2. Newly-onset or relapsed patients who requires initiation or continuation of glucocorticoids treatment; 3. The addition of glucocorticoids was started at lower than 10 mg/d.
1. Patients who were diagnosed as other autoimmune diseases; 2. Patients who were diagnosed as malignant diseases; 3. Pregnant and lactating women； 4. Active infection: HIV, HCV, HBV, TB； 5. Severe irreversible damage of organ function; 6. Receipt of any biologic therapy or immunosuppressive agent other than GCs.