Clinical Study on the Safety and Efficacy of Autologous CD84 Chimeric Antigen Receptor T-Cell Therapy for Adult Relapsed/Refractory Acute Myeloid Leukemia.

Inclusion Criteria: 1. Ages 18-70 years (inclusive of boundary values), gender unrestricted. 2. Voluntarily participate in this clinical study, sign the informed consent form, have good compliance, and cooperate with follow-up visits. 3. Diagnosed with relapsed/refractory acute myeloid leukemia (AML), patients with relapsed/refractory AML must meet one of the following conditions: patients who have not achieved remission after two standard treatment courses; relapse within 12 months after complete remission; relapse after 12 months but have not achieved remission after one standard treatment; patients with second or subsequent relapses. Relapse is defined as the reappearance of leukemia cells in the peripheral blood or the presence of ≥5% blasts in the bone marrow (excluding other causes such as bone marrow regeneration after consolidation chemotherapy) or the infiltration of leukemia cells in extramedullary sites after achieving complete remission (CR) of AML, excluding cases where the above conditions occur after granulocyte colony-stimulating Factor （G-CSF） treatment. 4. Flow cytometry confirms the presence of CD84-positive blasts. 5. ECOG (Eastern Cooperative Oncology Group) score of 0-1. 6. Able to collect T cells that meet the required specifications. 7. Liver Function: Alanine Aminotransferase (ALT) ≤ 3 × Upper Limit of Normal (ULN); Aspartate Aminotransferase (AST) ≤ 3 × ULN; Total Bilirubin (TBIL) ≤ 1.5 × ULN (except in cases of Gilbert's syndrome). 8. Renal Function: Creatinine Clearance Rate (CrCl) ≥ 60 ml/minute (Cockcroft/Gault formula). 9. Coagulation Function: International Normalized Ratio (INR) ≤ 1.5 × Upper Limit of Normal (ULN), Prothrombin Time (PT) ≤ 1.5 × ULN. 10. Cardiac Function: Hemodynamic stability is good, with a Left Ventricular Ejection Fraction (LVEF) ≥ 50%. 11. Pulmonary Function: No clinically significant pleural effusion, baseline oxygen saturation \>92%. 12. Female subjects of childbearing potential and male subjects with partners of childbearing potential must use medically recognized contraceptive measures or abstain from sexual activity during the study treatment period and for at least 6 months after the study treatment ends. Female subjects of childbearing potential must have a negative serum human chorionic gonadotropin （HCG） test within 7 days prior to study enrollment and must not be breastfeeding. Exclusion Criteria: 1. Individuals with a history of severe drug allergies or allergic constitution; 2. Those with uncontrolled active infections; 3. Individuals with severe cardiac diseases, such as angina, myocardial infarction, heart failure, and arrhythmias; 4. Subjects with congenital immunoglobulin deficiencies; 5. Patients with other malignant tumors (except for non-melanoma skin cancer, carcinoma in situ of the cervix, bladder cancer, and breast cancer with more than 5 years of disease-free survival); 6. Subjects with end-stage renal failure; 7. Subjects who are positive for Hepatitis B surface antigen (HBsAg) or Hepatitis B core antibody (HBcAb) with peripheral blood HBV DNA levels above the detection limit; those positive for Hepatitis C virus (HCV) antibody with peripheral blood HCV RNA positivity; individuals positive for Human Immunodeficiency Virus (HIV) antibody; and those with positive syphilis tests; 8. Individuals with mental illnesses and severe cognitive impairments; 9. Those who have participated in other clinical trials within the last month; 10. Pregnant or breastfeeding women; 11. Subjects deemed inappropriate for the study by the investigator or for other reasons not suitable for inclusion in this study; 12. Recipients of allogeneic transplants who relapsed within three months or still have graft-versus-host disease (GVHD) reactions more than three months after the transplant; 13. Central nervous system leukemia involvement.