Inclusion Criteria:
* Subjects with refractory Graves disease, which is defined as meeting any one of the following criteria: a. Failure to discontinue medication after continuous standard antithyroid therapy for ≥ 3 years; b. Hyperthyroid state requiring medication after receiving ≥ 2 times of radioiodine therapy (with the last dose of radioiodine administered at least 6 months prior); c. Relapse ≥ 2 times after cessation of medication upon meeting the criteria for treatment discontinuation.
* Serum TRAb ≥ 3 times greater than normal range (≥ 5 IU/L)
* Positive expression of CD19 on peripheral blood B cells determined by flow cytometry.
* Participation in this clinical study is willing to sign an informed consent with good compliance with treatment and follow-up.
(Criteria for treatment discontinuation is define as receiving continuous anti-thyroid drug therapy for ≥18 months, and maintaining euthyroid status for ≥6 months, plus negative TRAb and TSI. Relapse is defined as recurrence of hyperthyroidism and positive TRAb/TSI after meeting the criteria for treatment discontinuation and stopping medication.)
Exclusion Criteria:
* History of severe drug allergies or allergic constitution;
* Presence or suspicion of uncontrolled infections requiring intravenous treatment (fungal, bacterial, viral or other);
* Presence of central nervous system disorders (including epilepsy, psychosis, cerebrovascular accident, encephalitis, CNS vasculitis, etc);
* Presence of clinically significant heart diseases (e.g., angina pectoris, myocardial infarction, heart failure, severe arrhythmias, etc);
* Subjects with congenital immunoglobulin deficiency;
* Patients with malignant tumors;
* Subjects who are: 1. HBsAg or HBcAb positive with detectable peripheral blood HBV DNA; 2. HCV antibody positive with detectable HCV RNA; 3. Positive HIV antibody; 4. Syphilis test positive;
* Subjects with psychiatric disorders or severe cognitive dysfunction;
* Hematopoietic function: a. White blood cell count \< 3.5×10\^9/L b. Neutrophil count \< 1.5 x 10\^9/L; c. Hemoglobin \< 110g/L.
* Liver function: ALT\> 3×ULN, AST \> 3×ULN, TBIL \> 2.5×ULN.
* Renal function: creatinine clearance rate (CrCl) \< 60 ml/minute (calculated based on Cockcroft/Fault formula).
* Cardiac function: LVEF \< 55%
* Coagulation function: International standardized ratio (INR) ≥ 1.5×ULN, prothrombin time(PT) \>1.5 × ULN.
* Participation in other clinical trials within 3 months prior to enrollment;
* Pregnancy or planning pregnancy;
* Other conditions considered by investigators as unsuitable for participation.
