Patients with acute leukemia derived from T lymphocytes have the characteristics of high expression of CD7 antigen, such as acute T lymphocyte leukemia (T-ALL).CAR-T therapy is to genetically modify the patient's T lymphocytes to target and eliminate tumor cells in a major histocompatibility complex-independent manner. CAR-T cells are costimulatory molecules that include single-chain antibodies (scFv) that recognize tumor-specific antigens, hinge regions, transmembrane regions, intracellular signaling regions (immunoreceptor tyrosine activation motif ITAM), and intracellular signaling regions. The chimeric antigen receptor of CD28 or CD137(4-1BB) conduction domain is expressed in a lentiviral vector, and the vector is transfected into autologous T cells, so that the modified CAR-T cells have targeting and specificity Recognizes and kills cancer cells expressing tumor antigens, and can proliferate and activate in vivo, but has no effect on cells that do not express the antigen

Inclusion Criteria:

• Age 12-65
• Sign informed consent
• Expected survival time ≥ 3 months
• CD7 positive refractory and relapsed acute leukemia
• Karnofsky score≥60
• ECOG score ≤ 2
• Have not received other immunotherapy within 3 months
• The CD7 expression rate on the surface of leukemia cells detected by flow cytometry is greater than 30%

Exclusion Criteria:

• Uncontrolled active infection
• Active viral hepatitis B or C
• HIV test positive
• Congenital immunodeficiency patients
• Pregnant and breastfeeding patients
• Patients with central nervous system tumors or central nervous system leukemia
• The patient and/or family members do not agree to the treatment plan