Clinical Significance And Mechanism Of Immunotherapy With Combined Three Kinds Of Cells For Operable Colorectal Cancer

BACKGROUND: Despite with better prognosis than other kind gastrointestinaltumors, quite a part of colorectal cancer patients still suffer recurrence ormetastasis. Surgery, chemotherapy and radiotherapy can kill tumor cells, whichalso make damage to immune function. As emerging means of cancer treatment,immunotherapy has showed efficacy in the treatment of solid tumors. Despiteclinic application of DCs, DC-AT and ATC alone, Immunotherapy with combinedthree kinds of cells for colorectal with various therapeutic approaches at differenttiming has never been reported. Being main effect cells of three kinds of cellsimmunotherapy, T lymphocytes can mediate persistent anti-tumor specificimmune with clonal expand and memory subsets formation, however, there wasno reported concerning mechanisms of T lymphocytes treatment in vivo.OBJECTIVE: To evaluate efficacy of Combined Three Kinds of Cells as anAdjuvant Treatment for Operable Colorectal Cancer and unveil the mechanism.METHODS:1. The patients with stage II–III Colorectal Cancer after radicalresection, including72patients receiving autologous DCs, DC-AT and ATC cellstreatment combined with chemotherapy (immunotherapy group) and112patientsin the corresponding period receiving chemotherapy alone (control group), wereretrospectively studied. The patients in the immunotherapy group werecomparable to those in the control group regarding the sex and age of patients,tumor site, histological type, clinical stage, and operation type. Overall survival(OS) was evaluated by the Kaplan–Meier analysis, then Further analysis of effectof cycles of immunotherapy.2.6simple peripheral blood of Colorectal Cancerpatients received immunotherapy were tested. A.in an attempt to evaluate impactof immunotherapy to the characteristic of memory T cells, the expression of CD45RO and CD62L were detected by flow cytometric method. B.CD4+T cellsand CD8+T cells were isolated from the PBMC, then the expression of TCRCDR3Repertoire were test through human TCR CDR3test kit. The cloned Vβ2and Vβ11were purified, cloned and sequence, nucleotide sequence of TCRCDR3were analyzed by Vector NTI version11and IMGT/V-QUEST.RESULTS:1. The5-year OS rate in the immunotherapy group was significantlyimproved compared to that in the control group (75.63%VS67.81%，P<0.05),thesame as the3-year OS rate(87.07%VS74.80%, P<0.05). Further study suggestspatients received three more cycles of immunotherapy have a better5-year OSrate than whose were less(82.10%VS69.90%，P<0.05),No serious side effect wasobserved in the immunotherapy group.2. there were clonal expansions ofVβ2,Vβ3,Vβ5,Vβ8and Vβ22in CD8+TCR of Colorectal Cancer patient.3.Withimmunotherapy, maintaining expanding Vβ2clonal and new clonal expansion ofVβ11emerged in CD8+TCR Repertoire.4. Percentage of CD8+central memory Tcells significantly improved after immunotherapy.5. The first to the third aminoacid sequence of TCR CDR3Vβ2District were same, and there are partly sameamino acid sequences in D and J region.CONCLUSION:1.This study suggests that immunotherapy with Three Kinds ofcells may serve as an adjuvant treatment to prolong the survival of patients withstage II–III Colorectal Cancer.2. Immunotherapy restore specific antitumorimmunity characteristic of clonal expansion T cells and memory T cells.