Baricitinib Plus Glucocorticoid for Eosinophilia in IgG4-RD

Inclusion Criteria: 1. All patients must meet the following diagnostic criteria of IgG4RD (2020): 1) and radiological features: One or more organs show diffuse or localized swelling or a mass or nodule characteristic of IgG4-RD. In single organ involvement, lymph node swelling is omitted. 2) serological diagnosis: Serum IgG4 levels greater than 135 mg/dl. 3) diagnosis diagnosis: Positivity for two of the following three criteria: a. Dense lymphocyte and plasma cell infiltration with fibrosis. b. Ratio of IgG4-positive plasma cells /IgG-positive cells greater than 40% and the number of IgG4-positive plasma cells greater than 10 per high powered field. c. Typical tissue fibrosis, particularly storiform fibrosis, or obliterative phlebitis. Patients fulfill (1) + (2) + (3) are diagnosed as definite IgD4RD; (1) + (2): possible IgG4RD; (1) + (3): probable IgG4RD. exclusion of other diseases. 2. Active IgG4-RD (Responder Index ≥ 2 points for each involved organ) 3. The counts of peripheral blood eosinophil cells ≥0.75×109/L Exclusion Criteria: 1. Patients who is not able to discontinue GC 2. Pregnancy or breastfeeding or planning to get pregnant within 2 years 3. Received glucocorticoids, immunosuppressants, biological agents or JAK inhibitors within 3 months 4. Allergic to Baricitinib 5. Concomitant other autoimmune diseases 6. Malignancy 7. Chronic HBV infection, latent tuberculosis, or active infection 8. Server liver or renal dysfunction, or heart failure.