In recent years, a new surge in tumor immunotherapy research has occurred as more and more human tumor immune rejection antigens have been identified and more is known about the process of antigen-specific T cell activation and expansion. Relay immune cell therapy refers to the infusion of autologous or allogeneic immune effector cells to kill tumor cells in patients, which is more suitable for patients with low cellular immune function (such as after receiving high-dose chemotherapy, radiotherapy or bone marrow transplantation, or viral infection resulting in impaired number and function of immune cells), especially for leukemia patients. The advantages of the effector cell therapy of transitional immunity: 1. The treatment of immune cells in vitro can bypass various immune barriers in vivo, thus selectively operating the anti-tumor immune response. For example, freshly isolated tumor-infiltrating lymphocytes (TIL) often lack anti-tumor effects, while specific anti-tumor effects can be restored or their antigen-specific tolerance reversed after a period of culture under certain conditions in vitro. 2. The in vitro activation and expansion of immune cells can avoid the serious toxic reactions brought by the massive application of some agents in vivo. Sources and properties of CIK and DC-CIK cells: 1. CIK: It is a killer cell with anti-tumor activity produced by culturing peripheral blood lymphocytes with anti-CD3 monoclonal antibody (MabCD3), gamma interferon (IFNγ), interleukin (IL-2) and IL-1 . Their proliferation multiplier, total antitumor effect and antitumor effect in animals are stronger than those of LAK cells commonly used in the past. 2.DC-CIK cells: The cell therapy research group led by Prof. Lu Daopei of Peking University School of Medicine called DC-CIK for the immune effector cells produced by co-culture of DC carrying leukemia cell antigens with autologous peripheral blood lymphocytes. in DC-CIK, T cells, especially In DC-CIK, the proliferation fold and IFNγ secretion of T cells, especially the killer T cells, are significantly higher than in CIK. Clinical study of CIK and DC-CIK for acute leukemia A research group led by Prof. Lu Daopei was the first in the world to use in vitro cultured autologous CIK for intravenous infusion in two patients with chemotherapy-refractory leukemia combined with hepatitis C. After treatment, not only did the patients’ leukemia increase, but they were also treated with DC-CIK. After the treatment, the patients not only had a negative leukemia fusion gene (AML/ETO or PML/RARα), but also a negative blood hepatitis C virus gene (HCV-RNA) and improved liver function. To date, the group has treated 111 patients with acute leukemia in complete remission (CR) after chemotherapy or (and) autologous hematopoietic stem cell transplantation (ASCT) with autologous CIK or autologous DC-CIK. 96 patients with CR treated with CIK or DC-CIK had a 5-year disease-free survival ( DFS) was 66%, which was significantly higher than that of patients treated with chemotherapy alone or ASCT at this hospital. After CIK or DC-CIK treatment, the residual leukemic chromosomal and/or genetic markers turned negative in 14/15 cases; the liver and spleen of 3/6 patients with hepatosplenomegaly and the extramedullary masses of those with extramedullary leukemia were significantly reduced or even disappeared, and they have survived disease-free to date. Autologous CIK or DC-CIK transfusion was relatively safe, with no serious adverse reactions occurring in 1 case, and those that occurred (such as chills, chills, fever and fatigue) all disappeared within 24 hours. After completing the treatment, many patients were able to continue working or studying. The success of autologous CIK or DC-CIK for acute leukemia or chronic hepatitis C provides a safe and effective novel treatment for acute leukemia or chronic hepatitis C. It also provides a good basis for immunotherapy for other malignant diseases or chronic viral infectious diseases.