Exploratory Study on mRNA Therapy Targeting CD19 for the Treatment of Refractory Autoimmune Diseases

Inclusion Criteria: * 1\. Age range of 14-70 years old (including threshold), gender not limited; * 2\. KPS score\>60 points, life expectancy greater than 6 months; * 3\. Male and female patients of appropriate age must use reliable methods of contraception before entering the trial, during the research process until 30 days after discontinuation of medication; Reliable contraceptive methods will be determined by the primary researchers or designated personnel; * 4\. Those who can understand this experiment and have signed the informed consent form. * 5\. Before screening (at baseline), corresponding conditions should be met; * 6\. Indications for severe, recurrent, or refractory immune related diseases, including immune thrombocytopenia (ITP), autoimmune hemolytic anemia (AIHA), systemic lupus erythematosus（SLE），systemic sclerosis （SSc） etc., meet the corresponding inclusion criteria; For other types of diseases, researchers will assess whether they meet the inclusion requirements after fully evaluating the risks and benefits based on the patient's treatment needs. Exclusion Criteria: * 1\) Study participants who are allergic or hypersensitive to any component of the investigational drug, including those who are allergic to messenger RNA (mRNA) vaccines or other RNA LNP products. * 2\) Merge any active infections that require antibiotic treatment and have not been controlled for at least one week prior to D1 administration. * 3\) Malignant tumors diagnosed within the first 2 years of screening are excluded, except for skin basal cell carcinoma, squamous cell carcinoma, or cervical cancer in situ that has been adequately treated. * 4\) Uncontrolled ischemic heart disease, including unstable angina within the previous 6 months of screening, or evidence of active ischemic heart disease on electrocardiogram. * 5\) New York Heart Association (NYHA) grade III-IV heart failure. * 6\) Study participants with combined active hepatitis B virus (HBV) infection \[defined as surface antigen (HBsAg) positive and HBV DNA positive (detected by PCR)\]. * 7\) Study participants with combined active hepatitis C virus (HCV) infection (defined as HCV RNA positive (detected by PCR), regardless of anti HCV antibody status). * 8\) Human immunodeficiency virus (HIV) infection or history of HIV infection. * 9\) Study participants who tested positive for Treponema pallidum specific antibodies. * 10\) There may be active infection of Mycobacterium tuberculosis. * 11\) Women who are currently pregnant, breastfeeding, or planning to become pregnant. * 12\) Combining severe or recently (\<2 months) diagnosed medical conditions, as determined by the researchers, may affect the study participants' tolerance to the study drug or their ability to complete the study process. * 13\) Received attenuated live vaccine or protein subunit vaccine within 30 days prior to the first study medication.