Orchestrating the Impact of KIR/HLA Interactions on Kidney Transplant.

This study examines the interplay between human leukocyte antigen (HLA) compatibility and killer-cell immunoglobulin-like receptor (KIR) genotypes in influencing kidney transplantation outcomes. Understanding these interactions is crucial for improving graft survival and minimizing rejection risks. We evaluated 84 kidney transplant recipients, dividing them into two groups based on post-transplant outcomes: there were 68 with stable graft function (SGF) and 16 who experienced chronic rejection (CR). Patients were selected based on specific inclusion criteria. HLA mismatches (Class I: HLA-A, -B; Class II: HLA-DR) and KIR genotypes were determined using standard genotyping techniques. Statistical analyses, including logistic regression, were performed to correlate these factors with transplant outcomes. Significant age differences were observed, with younger patients more likely to experience graft rejection, while no significant gender-based differences were noted. A significant correlation was found between Class II mismatches and increased rejection rates, highlighting the importance of HLA-DR compatibility. Further analysis revealed that certain inhibitory KIRs, such as KIR3DL1, were associated with favorable outcomes, suggesting a protective role against graft rejection. These findings were corroborated by evaluating serum creatinine levels over multiple years, serving as a biomarker for renal function post transplant. This study underscores the critical need for meticulous HLA matching and the consideration of KIR genotypes in pre-transplant evaluations to enhance graft survival and minimize rejection risks. Integrating these genetic factors into routine clinical assessments could significantly improve personalized transplant medicine strategies, ultimately enhancing patient outcomes. Further research is needed to explore the underlying mechanisms and validate these findings in larger, diverse populations.

Increased donor inhibitory KIR are associated with reduced GVHD and improved survival following HLA-matched unrelated donor HCT in paediatric acute leukaemia.

Killer immunoglobulin-like receptor (KIR) and KIR-ligand (KIRL) interactions play an important role in natural killer cell-mediated effects after haematopoietic stem cell transplantation (HCT). Previous work has shown that accounting for known KIR-KIRL interactions may identify donors with optimal NK cell-mediated alloreactivity in the adult transplant setting. Paediatric acute leukaemia patients were retrospectively analysed, and KIR-KIRL combinations and maximal inhibitory KIR ligand (IM-KIR) scores were determined. Clinical outcomes were examined using a series of graphs depicting clinical events and endpoints. The graph methodology demonstrated that prognostic variables significant in the occurrence of specific clinical endpoints remained significant for relevant downstream events. KIR-KIRL combinations were significantly predictive for reduced grade 3-4 aGVHD likelihood, in patients transplanted with increased inhibitory KIR gene content and IM-KIR = 5 scores. Improvements were also observed in associated outcomes for both ALL and AML patients, including relapse-free survival, GRFS and overall survival. This study demonstrates that NK cell KIR HLA interactions may be relevant to the paediatric acute leukaemia transplant setting. Reduction in aGVHD suggests KIR effects may extend beyond NK cells. Moving forward clinical trials utilizing donors with a higher iKIR should be considered for URD HCT in paediatric recipients with acute leukaemia to optimize clinical outcomes.

Killer instincts: natural killer cells as multifactorial cancer immunotherapy.

Natural killer (NK) cells integrate heterogeneous signals for activation and inhibition using germline-encoded receptors. These receptors are stochastically co-expressed, and their concurrent engagement and signaling can adjust the sensitivity of individual cells to putative targets. Against cancers, which mutate and evolve under therapeutic and immunologic pressure, the diversity for recognition provided by NK cells may be key to comprehensive cancer control. NK cells are already being trialled as adoptive cell therapy and targets for immunotherapeutic agents. However, strategies to leverage their naturally occurring diversity and agility have not yet been developed. In this review, we discuss the receptors and signaling pathways through which signals for activation or inhibition are generated in NK cells, focusing on their roles in cancer and potential as targets for immunotherapies. Finally, we consider the impacts of receptor co-expression and the potential to engage multiple pathways of NK cell reactivity to maximize the scope and strength of antitumor activities.

Impact of HLA Class I Antigen, Killer Inhibitory Receptor, and FCGR3A Genotypes on Breast Cancer Susceptibility and Tumor Stage.

BACKGROUND: The identification in breast cancer (BC) of novel genetic biomarkers regulating natural killer (NK) cell function, including the HLA, KIR, and CD16A (FCGR3A), may be still a challenge. OBJECTIVE: We aimed to evaluate whether the combined effect of these polymorphisms has an impact on BC susceptibility and progression. METHODS: 47 BC Italian patients and healthy individuals (39 females and 66 males/females) were genotyped by Sanger sequencing (HLA-C exon 2-4 and FCGR3A-158V/F, 48L/R/H) and PCR-SSP typing (KIR genes). RESULTS: HLA-C gene allele analysis showed the group C1, with HLA-C*07:02:01 allele, to be significantly associated with tumor progression (16.7% vs. 4.0%, p=0.04, OR=4.867), and instead, group C2, with HLA-C*05:01:01, was protective against disease susceptibility (0.0% vs. 7.2%, p=0.019, OR=0.087). In addition, we highlighted a significant reduction of the KIR2DS4ins in BC patients (pcorr.=0.022) and an increased combined presence of KIR2DL1 and KIR2DS1 genes in advanced BC patients compared to earlier stages (66.7% vs. 19.2%, p=0.002). The concurrent lack of KIR2DL2 and KIR2DS4 genes in the presence of HLA-C2 alleles was significantly associated with increased susceptibility to BC (p=0.012, OR=5.020) or with lymph node involvement (p=0.008, OR=6.375). Lastly, we identified different combinations of the FCGR3A-48/158 variants and KIR genes in BC patients compared to controls. CONCLUSION: Our findings suggest that in the development of BC probably exists a disorder of the NK innate immunity influenced by KIR/HLA-C gene content and FCGR3A-158 polymorphisms and that the combined analysis of these biomarkers might help predict genetic risk scores for tailored screening of BC patients in therapy.

Human CD8+ T-Cell Populations That Express Natural Killer Receptors.

CD8+ T cells are activated by TCRs that recognize specific cognate Ags, while NK-cell activation is regulated by a balance between signals from germline-encoded activating and inhibitory NK receptors. Through these different processes of Ag recognition, CD8+ T cells and NK cells play distinct roles as adaptive and innate immune cells, respectively. However, some human CD8+ T cells have been found to express activating or inhibitory NK receptors. CD8+ T-cell populations expressing NK receptors straddle the innate-adaptive boundary with their innate-like features. Recent breakthrough technical advances in multi-omics analysis have enabled elucidation of the unique immunologic characteristics of these populations. However, studies have not yet fully clarified the heterogeneity and immunological characteristics of each CD8+ T-cell population expressing NK receptors. Here we aimed to review the current knowledge of various CD8+ T-cell populations expressing NK receptors, and to pave the way for delineating the landscape and identifying the various roles of these T-cell populations.

A Novel Hypothesis: Certain KIR/Cognate Ligand Containing Genotypes Differ in Frequency Among Patients With Myeloma and Have an Effect on Age of Disease Onset.

BACKGROUND: Natural killer (NK) cells are known to have cytotoxic effects mediated through killer immunoglobulin-like receptors (KIRs) and their cognate ligands. Role of KIRs in myeloma is yet unresolved. PATIENTS AND METHODS: KIR genotypes and ligands of 204 newly diagnosed MM patients are compared with 424 healthy subjects. Statistical analysis included t-test, chi-square and binary logistic regression. RESULTS: KIR ligands were significantly more (C2C2: 27.5% vs 15.1%; OR 2.128; 95% CI, 1.417-3.196; P < .001) or less (C1C2: 40.2% vs 51.9%; OR 0.623; 95% CI, 0.444-0.874; P = .006) frequent among MM. Co-occurrence of genotype AA with C2C2 was also higher in frequency among MM (OR 2.509; 95% CI, 1.171-5.378; P = .015) likewise cAB1 with C1C2 was less frequent (OR 0.553; 95% CI, 0.333-0.919; P = .021). Genotypes AA with C1C1, cAB1 with C1C2 or C1C2 alone were associated with a delay (median age: 61 [48-73]; P = .044; 62 [31-81]; P = .030 or 59 [31-85]; P = .028), but AA with C2C2 with an earlier age of onset (48 [29-77]; P = .042). In multivariate analysis including R-ISS, light chain, KIR genotype/ligands; ligand C1C2 (P = .02) and genotype AA-C1C1 (P = .037) were independently associated with age of onset ≥60. CONCLUSION: C1C2 and C2C2 alone or in combination with KIR genotype (cAB1 and AA, respectively), is observed in less or higher frequency among MM cases and associated with delayed/earlier age of onset, respectively. Genotype AA-C1C1 although in similar frequency between patients and healthy subjects, is also associated with delay. To our knowledge, this is the first study demonstrating an association between KIR and MM onset age, independent from R-ISS or light chain type.

Donor selection for adoptive immunotherapy with NK cells in AML patients: Comparison between analysis of lytic NK cell clones and phenotypical identification of alloreactive NK cell repertoire.

Natural killer (NK) cell-based adoptive immunotherapy in leukemia patients is an emerging field of interest based on clinical evidence of efficacy and safety. Elderly acute myeloid leukemia (AML) patients have been successfully treated with NK cells from HLA-haploidentical donors, especially when high amounts of alloreactive NK cells were infused. The aim of this study was comparing two approaches to define the size of alloreactive NK cells in haploidentical donors for AML patients recruited in two clinical trials with the acronym "NK-AML" (NCT03955848), and "MRD-NK". The standard methodology was based on the frequency of NK cell clones capable of lysing the related patient-derived cells. The alternative approach consisted of the phenotypic identification of freshly derived NK cells expressing, as inhibitory receptors, only the inhibitory KIR(s) specific for the mismatched KIR-Ligand(s) (HLA-C1, HLA-C2, HLA-Bw4). However, in KIR2DS2+ donors and HLA-C1+ patients, the unavailability of reagents staining only the inhibitory counterpart (KIR2DL2/L3) may lead to an underestimated identification of the alloreactive NK cell subset. Conversely, in the case of HLA-C1 mismatch, the alloreactive NK cell subset could be overestimated due to the ability of KIR2DL2/L3 to recognize with low-affinity also HLA-C2. Especially in this context, the additional exclusion of LIR1-expressing cells might be relevant to refine the size of the alloreactive NK cell subset. We could also associate degranulation assays, using as effector cells IL-2 activated donor peripheral blood mononuclear cells (PBMC) or NK cells upon co-culture with the related patient target cells. The donor alloreactive NK cell subset always displayed the highest functional activity, confirming its identification accuracy by flow cytometry. Despite the phenotypic limitations and considering the proposed corrective actions, a good correlation was shown by the comparison of the two investigated approaches. In addition, the characterization of receptor expression on a fraction of NK cell clones revealed expected but also few unexpected patterns. Thus, in most instances, the quantification of phenotypically defined alloreactive NK cells from PBMC can provide data similar to the analysis of lytic clones, with several advantages, such as a shorter time to achieve the results and, perhaps, higher reproducibility/feasibility in many laboratories.

Immunogenomics of Killer Cell Immunoglobulin-Like Receptor (KIR) and HLA Class I: Coevolution and Consequences for Human Health.

Interactions of killer cell immunoglobin-like receptors (KIR) with human leukocyte antigens (HLA) class I regulate effector functions of key cytotoxic cells of innate and adaptive immunity. The extreme diversity of this interaction is genetically determined, having evolved in the ever-changing environment of pathogen exposure. Diversity of KIR and HLA genes is further facilitated by their independent segregation on separate chromosomes. That fetal implantation relies on many of the same types of immune cells as infection control places certain constraints on the evolution of KIR interactions with HLA. Consequently, specific inherited combinations of receptors and ligands may predispose to specific immune-mediated diseases, including autoimmunity. Combinatorial diversity of KIR and HLA class I can also differentiate success rates of immunotherapy directed to these diseases. Progress toward both etiopathology and predicting response to therapy is being achieved through detailed characterization of the extent and consequences of the combinatorial diversity of KIR and HLA. Achieving these goals is more tractable with the development of integrated analyses of molecular evolution, function, and pathology that will establish guidelines for understanding and managing risks. Here, we present what is known about the coevolution of KIR with HLA class I and the impact of their complexity on immune function and homeostasis.

KIR in Allogeneic Hematopoietic Stem Cell Transplantation: Need for a Unified Paradigm for Donor Selection.

Allogeneic hematopoietic stem cell transplantation (aHSCT) is a lifesaving therapy for hematological malignancies. For years, a fully matched HLA donor was a requisite for the procedure. However, new immunosuppressive strategies have enabled the recruitment of viable alternative donors, particularly haploidentical donors. Over 95% of patients have at least two potential haploidentical donors available to them. To identify the best haploidentical donor, the assessment of new immunogenetic criteria could help. To this end, the clinical benefit of KIR genotyping in aHSCT has been widely studied but remains contentious. This review aims to evaluate the importance of KIR-driven NK cell alloreactivity in the context of aHSCT and explain potential reasons for the discrepancies in the literature. Here, through a non-systematic review, we highlight how the studies in this field and their respective predictive models or scoring strategies could be conceptually opposed, explaining why the role of NK cells remains unclear in aHCST outcomes. We evaluate the limitations of each published prediction model and describe how every scoring strategy to date only partly delivers the requirements for optimally effective NK cells in aHSCT. Finally, we propose approaches toward finding the optimal use of KIR genotyping in aHSCT for a unified criterion for donor selection.

Expression of Killer Cell Immunoglobulin-like Receptors (KIR) in Sex-associated Malignancies

@#Introduction: Sex shapes immune response with possible consequence on tumor immune escape. Acute lymphoblastic leukemia (ALL) predominates in males while ovarian cancer (OC) occurs in females. NK cells essential for tumor killing may have male preponderance. Association of sex, NK cell activity and malignancies is unclear. We hypothesize that sex differentially affects KIR expressions in sex-biased cancers. Method: Expression of inhibitory (KIR2DL1-5 and KIR3DL1-3) and activating (KIR2DS1-2 and 4-5 and KIR3DS1) genes in B-, T-cell ALL, OC and normal controls were determined by reverse-transcription polymerase-chain-reaction. Result: All normal males (but not females) expressed the framework genes and generally maintained haplotype A, except KIR3DL1. Normal females expressed more activating KIRs. Frequencies of KIR2DL1, 2DL4 and 2DS2 were significantly reduced among ovarian cancer patients. Sex difference in frequencies of KIR expression was not detected in ALL as majority were undetectable except framework gene KIR3DL2, was more frequent among T-ALL. Conclusion: Cancers may be associated with reduced KIR expression and influence of sex requires investigation.

Corrigendum: A Detailed View of KIR Haplotype Structures and Gene Families as Provided by a New Motif-Based Multiple Sequence Alignment.

[This corrects the article DOI: 10.3389/fimmu.2020.585731.].

Functionally Relevant Differences in Plasma Fatty Acid Composition and Expression of Cytotoxic and Inhibitory NK Cell Receptors between Healthy Young and Healthy Elder Adults.

(1) Background: In the healthy ageing, NK cell number is not modified; however, their spontaneous cytotoxicity decreases. We postulated that the age-dependent decline in metabolic activities might be responsible for this effect. (2) Methods: The fatty acid profile of 30 healthy young males (23 ± 4 years old, BMI 22.1 ± 1.3) and 30 older males (63 ± 5 years old, BMI 22.9 ± 2.5) donors were evaluated along with the expression of killing (KR) and inhibitory NK receptors (KIR) at basal level and after cultivation with fatty acids for 24 h. (3) Results: Significantly higher levels of oleic (p < 0.01), arachidonic (p < 0.001), lignoceric (p < 0.001), and nervonic acids (p < 0.0001) and significantly lower levels of docosapentaenoic and docosahexaenoic acids (p < 0.01) were found in elders as compared to young adults. At basal levels, significant (p < 0.005) differences in KR and KIR expression were encountered; 12/16 antigens. Treatment of cells with saturated fatty acids or arachidonic acid (AA) significantly enhanced KR expressions (p < 0.001). AA treatment decreased inhibitory KIR expression while docosahexaenoic, and eicosapentaenoic acid increased them. (4) Conclusions: Changes in fatty acids blood levels, and KR and KIR expression in NK cell, are age-dependent. Supplementation of NK cells with eicosapentaenoic or docosahexaenoic acid enhanced inhibitory KIR receptors' expression which may improve their cell function.

A Detailed View of KIR Haplotype Structures and Gene Families as Provided by a New Motif-Based Multiple Sequence Alignment.

Human chromosome 19q13.4 contains genes encoding killer-cell immunoglobulin-like receptors (KIR). Reported haplotype lengths range from 67 to 269 kb and contain 4 to 18 genes. The region has certain properties such as single nucleotide variation, structural variation, homology, and repetitive elements that make it hard to align accurately beyond single gene alleles. To the best of our knowledge, a multiple sequence alignment of KIR haplotypes has never been published or presented. Such an alignment would be useful to precisely define KIR haplotypes and loci, provide context for assigning alleles (especially fusion alleles) to genes, infer evolutionary history, impute alleles, interpret and predict co-expression, and generate markers. In order to extend the framework of KIR haplotype sequences in the human genome reference, 27 new sequences were generated including 24 haplotypes from 12 individuals of African American ancestry that were selected for genotypic diversity and novelty to the reference, to bring the total to 68 full length genomic KIR haplotype sequences. We leveraged these data and tools from our long-read KIR haplotype assembly algorithm to define and align KIR haplotypes at <5 kb resolution on average. We then used a standard alignment algorithm to refine that alignment down to single base resolution. This processing demonstrated that the high-level alignment recapitulates human-curated annotation of the human haplotypes as well as a chimpanzee haplotype. Further, assignments and alignments of gene alleles were consistent with their human curation in haplotype and allele databases. These results define KIR haplotypes as 14 loci containing 9 genes. The multiple sequence alignments have been applied in two software packages as probes to capture and annotate KIR haplotypes and as markers to genotype KIR from WGS.

Phenotypic and Functional Characterization of NK Cells in αßT-Cell and B-Cell Depleted Haplo-HSCT to Cure Pediatric Patients with Acute Leukemia.

NK cells can exert remarkable graft-versus-leukemia (GvL) effect in HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT). Here, we dissected the NK-cell repertoire of 80 pediatric acute leukemia patients previously reported to have an excellent clinical outcome after αßT/B-depleted haplo-HSCT. This graft manipulation strategy allows the co-infusion of mature immune cells, mainly NK and γδT cells, and hematopoietic stem cells (HSCs). To promote NK-cell based antileukemia activity, 36/80 patients were transplanted with an NK alloreactive donor, defined according to the KIR/KIR-Ligand mismatch in the graft-versus-host direction. The analysis of the reconstituted NK-cell repertoire in these patients showed relatively high proportions of mature and functional KIR+NKG2A-CD57+ NK cells, including the alloreactive NK cell subset, one month after HSCT. Thus, the NK cells adoptively transfused with the graft persist as a mature source of effector cells while new NK cells differentiate from the donor HSCs. Notably, the alloreactive NK cell subset was endowed with the highest anti-leukemia activity and its size in the reconstituted repertoire could be influenced by human cytomegalovirus (HCMV) reactivation. While the phenotypic pattern of donor NK cells did not impact on post-transplant HCMV reactivation, in the recipients, HCMV infection/reactivation fostered a more differentiated NK-cell phenotype. In this cohort, no significant correlation between differentiated NK cells and relapse-free survival was observed.

Immunological tolerance of low-risk HPV in recurrent respiratory papillomatosis.

Recurrent respiratory papillomatosis (RRP) is characterized by benign exophytic lesions of the respiratory tract caused by the human papillomavirus (HPV), in particular low-risk HPV6 and HPV11. Aggressiveness varies greatly among patients. Surgical excision is the current standard of care for RRP, with adjuvant therapy used when surgery cannot control disease recurrence. Numerous adjuvant therapies have been used to control RRP with some success, but none are curative. Current literature supports a polarization of the adaptive immune response to a T helper type 2 (Th2)-like or T regulatory phenotype, driven by a complex interplay between innate immunity, adaptive immunity and HPV6/11 proteins. Additionally, certain immunogenetic polymorphisms can predispose individuals to an HPV6/11-tolerant microenvironment. As a result, immunomodulatory efforts are being made to restore the host immune system to a more balanced T cell phenotype and clear viral infection. Literature has shown exciting evidence for the role of HPV vaccination with Gardasil or Gardasil-9 as both primary prevention, by decreasing incidence through childhood vaccinations, and secondary prevention, by treating active RRP disease. Multi-institution randomized clinical trials are needed to better assess their efficacy as treatment for active disease. Interestingly, a DNA vaccine has recently shown in-vitro success in generating a more robust CD8+ T cell response. Furthermore, clinical trials for programmed death 1 (PD-1) inhibitors are under investigation for RRP management. Molecular insights into RRP, in particular the interplay between RRP and the immune system, are needed to advance our understanding of this disease and may lead to the identification of immunomodulatory agents to better manage RRP.

Report from the Eleventh Killer Immunoglobulin-like Receptor (KIR) Workshop: Novel insights on KIR polymorphism, ligand recognition, expression and function.

The Eleventh Killer Immunoglobulin-like Receptor (KIR) Workshop was held in Camogli (Genoa, Italy) in October 2018. This congress brought together 113 participants working on KIR field. Fifty-eight studies have been presented, the majority of which included unpublished data. Thus, KIR workshop, allowing the meeting of people sharing their knowledge and experience in a friendly atmosphere, still represents a special event of fruitful discussion and exchange of novel breakthrough, results, and ideas. In this report, we summarize all the scientific contributions highlighting the most recent advances in KIR field. Forty abstracts presented at the KIR Workshop are published in this issue.

Human liver-derived CXCR6+ NK cells are predominantly educated through NKG2A and show reduced cytokine production.

NK cells have been implicated to affect the outcome of numerous liver diseases. In particular, members of the killer-cell Ig-like receptor (KIR) family, predominantly expressed by NK cells, have been associated with the outcome of hepatitis C virus infection and clearance of hepatocellular carcinoma. Inhibitory KIRs tune NK cell function through interaction with HLA class I, a process termed education. Nevertheless, the impact of the hepatic environment on NK cell education is incompletely understood. Therefore, we investigated the composition and function of hepatic KIR-expressing NK cells. Matched PBMC and hepatic lymphocytes were isolated from 20 individuals undergoing liver surgery and subsequently phenotypically analyzed for expression of KIRs and markers for tissue residency using flow cytometry. NK cell function was determined by co-culturing NK cells with the target cell line 721.221 and subsequent assessment of CD107a, IFN-γ, and TNF-α expression. Liver-resident CXCR6+ /CD56Bright NK cells lacked KIRs and were predominantly educated through NKG2A, while CXCR6- /CD16+ NK cells expressed KIRs and resembled peripheral blood NK cells. Hepatic NK cells showed lower response rates compared to peripheral blood NK cells; in particular, CXCR6+ NK cells were hyporesponsive to stimulation with target cells. The high proportion of educated NK cells in both subsets indicates the importance of self-inhibitory receptors for the balance between maintenance of self-tolerance and functional readiness. However, the reduced functionality of hepatic NK cells may reflect the impact of the tolerogenic hepatic environment on NK cells irrespective of NK cell education.

Diversity of Killer Cell Immunoglobulin-Like Receptors and Disease.

Natural killer (NK) cells are bone marrow-derived large granular lymphocytes defined by CD3negCD56pos and represent 5% to 25% of peripheral blood mononuclear cell fraction of the healthy humans. NK cells have a highly specific and sophisticated target cell recognition receptor system arbitrated by the integration of signals triggered by a multitude of inhibitory and activating receptors. Human NK cells express distinct families of receptors, including (1) killer cell immunoglobulin-like receptors, (2) killer cell lectin-like receptors, (3) leukocyte immunoglobulin-like receptors, and (4) natural cytotoxicity receptors.

Production of Recombinant Killer Immunoglobulin-Like Receptors for Crystallography and Luminex-Based Assays.

The killer immunoglobulin-like receptors (KIR) are a highly diverse family of cell-surface receptors that are of importance to the effector function of Natural Killer cells. KIR have been implicated in the detection and clearance of malignantly transformed cells and in the immune-control of viruses including HIV, HCV and CMV. Recently, the mismatching of donor and recipient KIR has been demonstrated to improve success of hematopoietic stem cell transplantation treatments of leukemias. Due to the high degree of diversity amongst the KIR, a number of strategies are required for the production of recombinant protein for medical, biochemical and structural applications. Each of these strategies has advantages and limitations and is suitable for different subsets of the KIR and their intended use. Here we describe the preparation of these proteins for crystallography and the novel adaptation of tetramer production for this protein family that is suitable for a number of assays including single-antigen bead binding by Luminex. These methods are intended to provide comprehensive details for the production and characterization of each KIR and to be broadly applicable to other cell surface receptors of the immune system.

[Immune reconstruct regularity profile of KIR2DL1 and KIR3DL1 in unrelated-donor allogeneic hematopoietic stem cell transplantation].

Objective: To investigate the immune reconstruct regularity profile of KIR2DL1 and KIR3DL1 in unrelated-donor allogeneic hematopoietic stem cell transplantation (allo-HSCT) with KIR-AA genotype. Method: 75 donor-recipient pairs were performed by KIR genotying using PCR-SSP, and all donors were identified with KIR-AA genotype. Dynamic detections (including unrelated-donor on the day of transplantation and the recipient each month post allo-HSCT) of the expression of KIR2DL1/3DL1 on NK cell and mRNA level were performed in 291 cases using flow cytometry (FCM) and real-time fluorescent quantitation PCR (RT-qPCR) . Result: ①The median expression of KIR2DL1 in unrelated-donor on transplant's day was 21.60%, the median expression of KIR2DL1 in recipient 1M, 2M, 3M and 3-6M after transplantation were 7.40%, 12.00%, 16.92%, 17.64% respectively. The median expression of KIR2DL1 in unrelated-donor on transplant's day was 265.14 copies/10 000abl copies, the median expression of KIR2DL1 in recipient 1M, 2M, 3M, 3-6M, 6-9M, 9-12M after transplantation were 332.17, 438.31, 723.25, 414.17, 180.76 and 234.67 copies/10 000abl copies respectively. The median expression of KIR2DL1 on NK cells and mRNA level gradually increased at all time points after transplantation, and reached the highest expression at 3 months after transplantation. But mRNA expression levels increased earlier than NK cell membrane proteins. ②The median expression of KIR3DL1 in unrelated-donors on transplant's day was 18.56%, the median expression of KIR3DL1 in recipient 1M, 2M, 3M, 3-6M after transplantation were 23.83%, 22.57%, 23.02%, 21.60% respectively. The median expression of KIR3DL1 in unrelated-donor on transplant's day was 572.29 copies/10 000abl copies, the median expression of KIR3DL1 in recipient 1M, 2M, 3M, 3-6M, 6-9M, 9-12M after transplantation were 1 233.74, 1 140.42, 876.73, 1 057.07, 739.02 and 514.43 copies/10 000abl copies respectively. The median expression of KIR3DL1 on NK cells and mRNA level were higher than donors at 1 month after transplantation, and stable expression at all time points after transplantation, so mRNA and NK cell membrane proteins expression increased at the same time. Conclusion: The immune reconstruct regularity of KIR2DL1 and KIR3DL1 gene were different, which provided an experimental basis for selecting the best time to detect the expressions of KIR2DL1 and 3DL1 after transplantation.