In Vivo CAR-T for Refractory Graves' Disease

Inclusion Criteria (Participants must meet all of the following criteria to be eligible for this study): * Age 18-75 years (inclusive), male or female. * Refractory Graves' disease, defined as meeting at least one of the following: a) Continuous antithyroid drug (ATD) therapy for ≥3 years without achieving criteria for ATD discontinuation; b) Meeting criteria for ATD discontinuation but experiencing ≥2 relapses after ATD withdrawal. * Positive serum TRAb. * Willing to use effective contraception for 12 months after study drug administration. * Voluntarily agrees to participate in the study, has signed the informed consent form, and is able to comply with study procedures and follow-up requirements. Exclusion Criteria (Participants meeting any of the following criteria will be excluded from the study): * History of severe drug allergy or known allergic predisposition. * Presence or suspected presence of uncontrolled active infection. * History of major organ transplantation (e.g., heart, lung, liver, kidney) or bone marrow/hematopoietic stem cell transplantation. * Presence of significant heart disease, such as angina, myocardial infarction, heart failure, or clinically significant arrhythmias. * Receipt of any mRNA-LNP product or other lipid nanoparticle (LNP)-based therapy within the past 2 years. * Receipt of a live vaccine within 30 days prior to screening. * History of malignant tumors. * Positive hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb) with peripheral blood HBV DNA above the detection limit; positive hepatitis C virus (HCV) antibody with detectable HCV RNA; positive human immunodeficiency virus (HIV) antibody; or positive syphilis test. * Presence of psychiatric disorders or severe cognitive impairment. * Hematologic dysfuction at screening, defined as any of the following: a. Neutrophil count \< 1.8 × 10⁹/L, b. Hemoglobin \< 110 g/L, c. Platelet count \< 50 × 10⁹/L * Impaired liver function, defined as any of the following: Alanine aminotransferase (ALT) \> 3 × ULN, Aspartate aminotransferase (AST) \> 3 × ULN, Total bilirubin \> 2.5 × ULN. * Impaired renal function: creatinine clearance rate (CrCl) \< 60 mL/min (Cockcroft-Gault formula). * Left ventricular ejection fraction (LVEF) \< 55%. * Coagulation abnormalities, defined as either: International normalized ratio (INR) \> 1.5 × ULN, Prothrombin time (PT) \> 1.5 × ULN * Pregnant or breastfeeding women. * Any other condition that, in the opinion of the investigator, would make the participant unsuitable for the study.