Study Of The Effect Of Natural Killer Cells Kill Dendritic Cells By Blockade Of CD158 Receptor Epitipe

Objective:Allogeneic hematopoietic stem cell transplantation(allo-HSCT) has prove to be an effective treatment means for hematologic malignancies. However,graft-versus-host disease(GVHD) is the frequent serious complication of allogeneic HSCT. Killer cell immunoglobulin receptor expressed on the surface of NK cells plays an important rolein hematopoietic stem cell transplantation. The donor NK cells alloreactivity is triggered by the lack of self-MHC class I engagement of inhibitory KIRs,which can kill recipient dendritic cell and reducing GVHD.At present,the study by blocking inhibitory receptor to regulate NK cell activity,killing the recipient DC cells,to analyse the relation of donor KIR genotype and the clinical prognosis of haploidallo-HSCT,and Further discuss thedonor and recipient KIR / HLA mode to select the best transplant donor,have limited Information.There are two parts in this study:One is to investigate the killing effect of donor NK cells on recipient DCs by blocking KIR2DL1 and KIR2DL2/L3 with monoclonal antibodies CD158 a and158b in vitro;the other is to evaluate the clinical efficacy and safety of human leukocyte antigen(HLA)-mismatched haploidentical stem cell transplantation(HSCT) in acute leukemia,and provide reference for selection of optimum donor and NK cell Adoptive immunotherapy after transplant toimprove the prognosis.Part 1 Study of the Effect of kill Dendritic Cells by Blockade of CD158 ReceptorEpitipe in vitro Methods:With 5 patients who werediagnosed acute leukemia and taken haploidallogene hematopoietic stem cell transplantation(allo-HSCT) from May, 2010 to December, 2014 and their donors as study objects. The 5 pairs of donor/recipient are analyzed to divide into KIR or HLA type before transplantation by means of Polymerase Chain Reaction-Sequence-specific Primers(PCR-SSP). Peripheral blood mononuclear cells were taken from donors/recipients. Donor NK cells gathered by the NK cell enrichment kit were taken as effector cells, and the recipient DC were taken as target cells. Monoclonal antibody against CD158 a and CD158 b was used to block donor KIR inhibitory receptors. The CCK-8colorimetric method was adopted to detect the killing effect of NK cells against target cells before and after blocking the inhibitory KIR respectively. Results:At the same effector-target ratio of 10:1, killing activity against recipient DC was improved significantly after blocking the donor NK cell inhibitory receptors, and killing activity was improved as the blocking antibodyconcentration was increased.There is statistical difference for each group(P<0.05). When only blocking KIR2DL2/L3 receptor epitope and at the same effector- target ratio of 10:1, killing effect of donor KIR2DL1 against target cellsof C1 group recipient was higher than that against C2 and C1/C2 groups. When blocking with different concentration of CD158 amonoclonal antibody, the killing effect was enhanced as the blocking antibody concentration was increased.Part 2 Outcomes of Haploidentical Hematopoietic Stem Cell Transplantation forAcute Leukemia Methods:5 acute leukemia patientswho received HLA-mismatched/haploidentical HSCT following conditioning regimen comprised of modified busulfan/cyclophosphamide(BU/CY) plus thymoglobulin(ATG) were analyzed Retrospectively. Results:5 patients achieved sustained and full donor-type engraftment.The median time to reach an absolute neutrophil count above 0.5×109/L was 13 days and that to aplatelet count exceeding 20×109/L was 18 days in HLA-haploidentical patients.1 patients who developed limited c GVHD. They are still alive without relapse at a median follow-up of 11 months(range:3-42 months). Conclusion:Blocking the inhibitory receptor KIR2DL1 and KIR2DL2/L3 of donor NK cells KIR by the monoclonal antibody against CD158 can improve the killing activity of donor NK cells againstrecipient DC; the killing effect of donor KIR2DL1 against recipient of C1 group target cells may be higher than that against C2 and C1/C2 groups; in haploidalloHSCT, donors express KIR2DL1, KIR2DL2/3 and KIR2DS1 simultaneously, the existence of Activated receptor KIR2DS1 may have a better effect on the prognosis of C2 group recipient; to analyze the KIR/HLA mode of donor/recipient can provide molecular basis for selection of optimum donor.