Killer Immunoglobulin Like Receptor In Allogeneic Hematopoietic Stem Cell Transplantation

PART Ⅰ Analysis of KIR Genotype, Haplotype, Receptor-LigandMismatch Model for Allogeneic Hematopoietic Stem CellTransplantationObjective： To establish three different models of killer immunoglobulin-likereceptors (KIR) genotypes, haplotypes and receptor-ligand mismatches and to analyze theimpact on the prognosis of allogeneic hemotopoietic stem cell transplantation(allo-HSCT).Methods: KIR and HLA genotypes were investigated in patient-donor pairsundergoing allo-HSCT. Three different models of KIR were established. There were KIRgenotype model, KIR haplotype model and receptor-ligand mismatch model.Results:1. Donor and recipient KIR gene-gene mismatch model: A donor andrecipient KIR gene match was defined as the donor and the recipient having the same KIRgenotype. A donor and recipient KIR gene mismatch was defined as a KIR gene that waspresent in the donor and absent in the recipient or vice versa.2. Donor KIR receptor andrecipient ligand model: patients were categorized according to their HLA-inhibitory KIRligand groups by determining whether they expressed (1) HLA-A3or-A11,(2) HLA-Bw4,or (3) HLA-Cw groups (C1or C2).3. Donor KIR haplotype model contains A haplotypeand B haplotype. Individuals with only group A genes were assigned as A/A genotype.Individuals with either1(A/B heterozygous) or2(B/B homozygous) B haplotypes wereassigned the genotype as B/x genotype. Further subdivision of the A haplotype intosubgroups resulted in designation of A-1and A-2. The gene combinations of A-1and A-2can be divided into AA-1, AA-2, and AA-3. For group B, there were15differenthaplotypes named as B1–B15according to their frequencies. Donor centromeric andtelomeric KIR haplotype model contains Cen-A, Tel-A, Cen-B and Cen-B.Conclusion: It is important to establish the three different models of KIR genotypes,haplotypes and receptor-ligand mismatches for analyzing the impact on the prognosis ofallo-HSCT. PART Ⅱ Donor Selection for KIR Gene Mismatches and KIR BHaplotype of the Centromeric Motifs Can Improve the Outcome afterHLA-identical Sibling Hematopoietic Stem Cell TransplantationObjective: After hematopoietic stem cell transplantation (HSCT), natural killer (NK)cell alloreactivity in human leukocyte antigen (HLA) cell of recipients is regulated bykiller immunoglobulin-like receptors (KIRs) on donor NK cells. The effect of KIRs onHSCT outcomes is controversial, particularly in those undergoing HLA-identical siblingHSCT.Methods: KIR and HLA genotypes were investigated in a5-year retrospective studycomprising219patient-donor pairs undergoing HLA-identical sibling HSCT for myeloidand lymphoid malignancies.Results: We found that39.7%of these pairs were mismatched for KIR with betteroverall survival (OS) and reduced Ⅲ-Ⅳ acute graft-versus-host disease (aGVHD),especially in acute myeloid leukemia (AML) patients. Bx1donor KIR genotype withhaplotype B on a telomeric region was a risk factor for OS and relapse-free survival (RFS).Donor centromeric and telomeric KIR haplotype analysis indicated an association of donorKIR B haplotype of the centromeric motifs (Cen-B) with improved OS and RFS and alower relapse rate. aGVHD was significantly lower in C1patients, especially for thosewith AML. No such effects were observed in patients with acute lymphoblastic leukemiaand chronic myelogenous leukemia.We found that34.2%(75/219) patients had CMV reactivation after HLA-identicalsibling HSCT. The median time of CMV reactivation was62days (26~265days). Indonor-receptor KIR match group,35.6%(47/132) patients had CMV reactivation, while indonor-receptor KIR mismatch group, the CMV reactivation rate was32.2%(28/87)(P=0.663)。CMV reactivation rate was different depend on donor KIR genotype. The CMVreactivation rate was39.5%(49/124),30.3%(23/76) and15.8%(3/19) in donor KIRgenotype A/A, A/B and B/B, respectively (P=0.036)。Donor centromeric and telomericKIR haplotype analysis indicated an association of donor KIR B haplotype of the telomericmotifs a lower CMV reactivation rate,24.4%(20/82) versus40.1%(55/137)(P=0.017).Conclusion: Our results suggest that KIR mismatches and a donor haplotype withCen-B confer significant survival benefits to HLA-identical sibling HSCT patients. PART Ⅲ Establishing of in vitro KIR/HLA Receptor-Ligand MismatchModel and Analysis of Activating KIR2DS4in Allogeneic HematopoieticStem Cell TransplantationObjective: To establish the in vitro KIR/HLA receptor-ligand mismatch model and toanalyze activating KIR2DS4in allo-HSCT.Methods: HLA genotypes were investigated in patients, and then the patients weredivided into two groups: HLA-C1group (C1/C1and C1/C2) and C2group (C2/C2). DonorKIR genotypes were invastigated and donors with KIR AA-1and AA-2were inexperimental group, donors with KIR A/B (2DS4Ful or Ful/Del) were in control group.Immature DCs (iDC) were generated from patients’ peripheral blood mononuclear cell(PBMCs). After5~7days, donors’CD3–CD16+CD56+NK cells were separated. Donor’ NKcells and patients’ iDCs were cocultured in RPMIc medium at different ratios (NK/DC) for16~24hours.Results：Donor’ NK cells and patients’ iDCs were cocultured in RPMIc medium atdifferent ratios. When the ratio was more than2.5:1, the expression of2DS4was increased.In A/A group, the expression of2DS4was increased (P=0.002), while we didn’t find thisincrease in B/x group. The positive rate of2DS4was (74.4±14.8)%in donor KIR AA-1group and (37.7±30.6)%in AA-2group (P=0.030). In AA-1group, the expression of2DS4was increased when NK/DC ratio was more than2.5:1compared with NKcell(without DC)(P=0.006)；In AA-2group, the expression of2DS4was increased whenNK/DC ratio was5:1compared with NK cell (without DC)(P=0.027). The expression of2DS4was significantly increased when Donor NK cells were cocultured with patients’iDCin C1-group (P=0.009). While in C2-group, the expression of2DS4was not increased (P=0.435).Conclusion: This study established the in vitro KIR/HLA mismatch modelsuccessfully and confirmed that KIR/HLA mismatch could enhance the NK cellallo-reactivity, thus could guide the selection of the most suitable donor, prevention ofrelapse, GVHD and CMV infection, and will lay the foundation of NK cell functionalexperiment.