Natural Killer Cell Subsets Research Articles

Associations between blood markers of glucose metabolism and characteristics of circulating lymphocytes

AimsThe pathophysiology of diabetes is not fully understood; recent research indicates close relations with immunological alterations. Therefore, the aim of this study was to investigate the associations between markers of glucose metabolism and characteristics of blood lymphocytes in a population-based cohort. MethodsThe analysis was based on data from 219 non-diabetic participants of the MEGA study in Augsburg, Germany, who were recruited between 2018 and 2021. The majority of participants were examined two different times with a time lag of 9 months. Fasting venous blood samples were taken and oral glucose tolerance tests (OGTT) were performed at both visits. Immune cells were analyzed from fresh blood using flow cytometry. The associations between fasting blood glucose levels, glucose levels at 2 hours after oral glucose bolus and glycated hemoglobin (HbA1c) concentrations and the quantity of different lymphocyte subsets were analyzed using linear mixed regression models with random intercept. P values were FDR-adjusted. ResultsHbA1c was negatively associated with the marginal zone B cells (IgD+ CD27+ B cells). Fasting glucose was positively associated with natural killer (NK) cells and 2-hour OGTT glucose was positively associated with NKT cells. Finally, HbA1c showed significantly negative associations with the CD57-PD1-NKT cell subset. ConclusionMarkers of glucose metabolism showed significant associations with B cell, NK cell and NKT cell subsets, which clearly indicates a relation between glucose metabolism and the adaptive immune system.

Prediction of cardiovascular outcomes by subtle changes in the peripheral immune cell landscape - insights from the LURIC single cell RNA-sequencing study (LuRNA)

Abstract Background and Aims Atherosclerosis and its clinical sequelae, myocardial infarction and stroke, represent the main causes of death worldwide. Although preclinical evidence has suggested the existence of an inflammatory response driving disease, the extend of cellular alterations in human atherosclerosis remains enigmatic. Here, we employ single cell RNA-sequencing (scRNA-seq) on peripheral blood mononucleated cells (PBMCs) in a well-defined cardiovascular risk cohort from the "Ludwigshafen Risk and Cardiovascular Health (LURIC) trial" to define changes in the immune cell landscape in atherosclerotic patients. Methods and Results Of 3317 patients enrolled in the LURIC trial between 1997 and 2000, we selected individuals with stable coronary-artery disease (CAD) (n=31) and healthy patients (no CAD) (n=16) by propensity score matching, adjusted for CRP, NTproBNP, Troponin T, LDL-C, and Cystatin-C, in a case-control design. scRNA-seq was performed by droplet sequencing on PBMCs stored in liquid nitrogen. Individual data sets were integrated and changes between healthy individuals and patients with CAD were evaluated on numeric and transcriptional level. Single cell transcriptomes were annotated using an established CITE-seq reference atlas. While bulk RNA-sequencing of PBMC preparations revealed only minor changes between both conditions, we identified several leukocyte populations on a single cell level with specific transcriptomes that were differentially regulated between both conditions. Interestingly, we found that several subsets of Natural Killer (NK) cells, T cells with an enrichment of proliferation-associated pathways, and a population resembling hematopoietic stem cells were more frequent in patients with CAD, while naïve phenotypes of B and T cells were overrepresented in the absence of CAD. Consistently, most T and B cell populations in patients with CAD were enriched in pathways associated with cell activation, immune receptor signalling, and differentiation. In addition, we detected restricted repertoires of T cell receptor sequences in several adaptive immune cell subtypes from patients with CAD, suggestive of increased cellular clonality and antigen-specificity. Finally, in a comparison of cellular frequencies with cardiovascular outcomes over more than 15 years, several immune cell subsets and cell-type specific transcriptional programs predicted cardiovascular death in this case-control scenario in multi-variate adjusted regression analysis. Notably, addition of scRNA-seq derived parameters was superior to traditional risk prediction with clinical characteristics and soluble biomarkers alone. Conclusion Employing scRNAseq, we demonstrate that atherosclerosis is associated with a profound change in the circulating immune cell landscape even in the absence of measurable differences in inflammatory biomarkers. These findings propose the usage of scRNAseq for the discovery of outcome-relevant cellular biomarkers in the future.

Causality of immune cells and endometriosis: a bidirectional mendelian randomization study

BackgroundEndometriosis, a prevalent chronic condition, afflicts approximately 10% of women in their reproductive years. Emerging evidence implicates immune cells in the pathogenesis of endometriosis, particularly in angiogenesis, tissue proliferation, and lesion invasion. This investigation employs two-sample Mendelian Randomization (MR) to dissect the bidirectional causal relationships between immune cell profiles and endometriosis.MethodsWe leveraged publicly available genome-wide association study (GWAS) data to elucidate the causal interplay between immune cell traits and endometriosis. Utilizing GWAS summary statistics ranging from accession numbers GCST90001391 to GCST90002121 and endometriosis data from the FinnGen study GWAS (8,288 endometriosis cases and 68,969 controls), we adopted stringent criteria for instrumental variable selection. We applied MR-Egger, weighted median, inverse variance weighted (IVW), and weighted mode methods to derive causal estimates. To address potential heterogeneity and pleiotropy, Cochran’s Q test, MR-Egger intercept, and leave-one-out analyses were executed. Reverse-direction MR and bidirectional MR analyses evaluated potential reciprocal causation and the influence of endometriosis on immune cell composition.ResultsOur analysis identified five immune phenotypes inversely associated with endometriosis risk. These phenotypes comprise: a percentage of CD11c + HLA-DR + + monocytes, CD25 expression on CD39 + CD4 + T cells, elevated CD25 on CD45RA + CD4 + non-regulatory T cells, HLA-DR intensity on HLA-DR + CD8 bright (CD8br) T cells, and the proportion of naïve double-negative (CD4 − CD8− %DN) T cells. In contrast, eleven phenotypes were positively correlated with endometriosis risk, including: CD127 expression on T cells, the proportion of CD24 + CD27 + B cells within lymphocytes, CD25 expression on CD28 + CD4 + T cells, CD28 expression on CD39 + activated regulatory T cells (activated Tregs), the frequency of bright CD33 HLA-DR + CD14 − cells within the CD33br HLA-DR + compartment, CD45 expression on lymphocytes and natural killer (NK) cells, activation status of central memory CD8 bright (CM CD8br) T cells, CX3CR1 expression on monocytes, and the percentage of HLA-DR + NK cells within the NK cell subset. Sensitivity assessments that excluded significant heterogeneity and pleiotropy confirmed the stability of these associations, thereby reinforcing the validity of our findings.ConclusionThis study provides novel evidence of the potential causal impact of specific immune cells on the risk of developing endometriosis. These findings enhance our understanding of endometriosis pathophysiology and may inform innovative approaches for its diagnosis and management. While our findings provide novel insights, limitations such as potential horizontal pleiotropy and reliance on European ancestry data should be considered. Future research should expand to diverse populations and incorporate individual-level data to refine these findings.

Innate immune response in COVID-19: single-cell multi-omics profile of NK lymphocytes in a clinical case series

BackgroundCOVID-19 pandemic caused by the Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) represents the biggest global health emergency in recent decades. The host immune response to SARS-CoV-2 seems to play a key role in disease pathogenesis and clinical manifestations, with Natural Killer (NK) lymphocytes being among the targets of virus-induced regulation.MethodsThis study performed a single-cell multi-omics analysis of transcripts and proteins of NK lymphocytes in COVID-19 patients, for the characterization of the innate immunological response to infection. NK cells were isolated from peripheral blood samples collected from adult subjects divided into 3 study groups: (1) non-infected subjects (Naïve group, n = 3), (2) post COVID-19 convalescent subjects (Healed group, n = 3) and (3) patients that were vaccinated against SARS-CoV-2 (Vaccine group, n = 3). Cells were then analysed by the BD Rhapsody System for the single-cell multi-omics investigation of transcriptome and membrane proteins.ResultsThe bioinformatic analysis identified 5 cell clusters which differentially expressed gene/protein markers, defining NK cell subsets as “Active NK cells” and “Mature NK cells”. Calculating the relative proportion of each cluster within patient groups, more than 40% of the Naïve group cell population was found to belong to Mature NKs, whereas more than 75% of the Vaccine group cell population belonged to the cluster of Active NKs. Regarding the Healed group, it seemed to show intermediate phenotype between Active and Mature NK cells. Differential expression of specific genes, proteins and signaling pathways was detected comparing the profile of the 3 experimental groups, revealing a more activated NK cell phenotype in vaccinated patients versus recovered individuals.ConclusionsThe present study detected differential expression of NK cell markers in relation to SARS-CoV-2 infection and vaccine administration, suggesting the possibility to identify key molecular targets for clinical-diagnostic use of the individual response to viral infection and/or re-infection.

Resting natural killer cells promote the progress of colon cancer liver metastasis by elevating tumor-derived stem cell factor.

The abundance and biological contribution of natural killer (NK) cells in cancer are controversial. Here, we aim to uncover clinical relevance and cellular roles of NK cells in colon cancer liver metastasis (CCLM). Here, we integrated single-cell RNA-sequencing, spatial transcriptomics (ST), and bulk RNA-sequencing datasets to investigate NK cells' biological properties and functions in the microenvironment of primary and liver metastatic tumors. Results were validated through an in vitro co-culture experiment based on bioinformatics analysis. Useing single-cell RNA-sequencing and ST, we mapped the immune cellular landscape of colon cancer and well-matched liver metastatic cancer. We discovered that GZMK+ resting NK cells increased significantly in tumor tissues and were enriched in the tumor regions of both diseases. After combining bulk RNA and clinical data, we observed that these NK cell subsets contributed to a worse prognosis. Meanwhile, KIR2DL4+ activated NK cells exhibited the opposite position and relevance. Pseudotime cell trajectory analysis revealed the evolution of activated to resting NK cells. In vitro experiments further confirmed that tumor-cell-co-cultured NK cells exhibited a decidual-like status, as evidenced by remarkable increasing CD9 expression. Functional experiments finally revealed that NK cells exhibited tumor-activating characteristics by promoting the dissociation of SCF (stem cell factor) on the tumor cells membrane depending on cell-to-cell interaction, as the supernatant of the co-culture system enhanced tumor progression. In summary, our findings revealed resting NK cells exhibited a clinical relevance with CCLM, which may be exploited for novel strategies to improve therapeutic outcomes for patients with CCLM.

High-dimensional analysis of NK cells in kidney transplantation uncovers subsets associated with antibody-independent graft dysfunction.

Natural Killer (NK) cells respond to diseased and allogeneic cells through NKG2A/HLA-E or Killer-cell Immunoglobulin-like receptor (KIR)/HLA-ABC interactions. Correlations between HLA/KIR disparities and kidney transplant pathology suggest an antibody-independent pathogenic role for NK cells in transplantation, but mechanisms remain unclear. Using CyTOF to characterize recipient peripheral NK cell phenotypes and function, we observed diverse NK cell subsets amongst participants that responded heterogeneously to allo-stimulators. NKG2A+/KIR+ NK cells responded more vigorously than other subsets, and this heightened response persisted post-kidney-transplant despite immunosuppression. In test and validation sets from two clinical trials, pre-transplant donor-induced release of cytotoxicity mediator, Ksp37, by NKG2A+ NK cells correlated with reduced long-term allograft function. Separate analyses showed Ksp37 gene expression in allograft biopsies lacking histological rejection correlated with death censored graft loss. Our findings support an antibody-independent role for NK cells in transplant injury and support further testing of pre-transplant, donor-reactive, NK cell-produced Ksp37 as a risk-assessing, transplantation biomarker.

Resting natural killer cells promote the progress of colon cancer liver metastasis by elevating tumor-derived stem cell factor

The abundance and biological contribution of natural killer (NK) cells in cancer are controversial. Here, we aim to uncover clinical relevance and cellular roles of NK cells in colon cancer liver metastasis (CCLM). Here, we integrated single-cell RNA-sequencing, spatial transcriptomics (ST), and bulk RNA-sequencing datasets to investigate NK cells’ biological properties and functions in the microenvironment of primary and liver metastatic tumors. Results were validated through an in vitro co-culture experiment based on bioinformatics analysis. Useing single-cell RNA-sequencing and ST, we mapped the immune cellular landscape of colon cancer and well-matched liver metastatic cancer. We discovered that GZMK+ resting NK cells increased significantly in tumor tissues and were enriched in the tumor regions of both diseases. After combining bulk RNA and clinical data, we observed that these NK cell subsets contributed to a worse prognosis. Meanwhile, KIR2DL4+ activated NK cells exhibited the opposite position and relevance. Pseudotime cell trajectory analysis revealed the evolution of activated to resting NK cells. In vitro experiments further confirmed that tumor-cell-co-cultured NK cells exhibited a decidual-like status, as evidenced by remarkable increasing CD9 expression. Functional experiments finally revealed that NK cells exhibited tumor-activating characteristics by promoting the dissociation of SCF (stem cell factor) on the tumor cells membrane depending on cell-to-cell interaction, as the supernatant of the co-culture system enhanced tumor progression. In summary, our findings revealed resting NK cells exhibited a clinical relevance with CCLM, which may be exploited for novel strategies to improve therapeutic outcomes for patients with CCLM.

CD151 identifies an NK cell subset that is enriched in COVID-19 patients and correlates with disease severity

Severe coronavirus disease 2019 (COVID-19) often leads to acute respiratory distress syndrome and multi-organ dysfunction, driven by a dysregulated immune response, including a cytokine storm with elevated proinflammatory cytokine levels. Natural killer (NK) cells are part of the innate immune system with a fundamental role in the defense against viral infections. However, during COVID-19 acute infection, they exhibit an altered phenotype and impaired functionality contributing to the immunopathogenesis of the disease. In this work, we have studied a cohort of patients with COVID-19 (ranging from mild to severe) by analyzing IL-15, TGF-β, PlGF and GDF-15 plasma levels and performing multiparametric flow cytometry studies. Our results revealed that severe COVID-19 patients exhibited high levels of IL-15, PlGF and GDF-15, along with an enrichment of anNK cell subset expressing the CD151 tetraspanin, which correlated with IL-15 plasma levels and disease severity. In patients, these CD151+ NK cells displayed a more activated phenotype characterized by an increased expression of HLA-DR, CD38 and granzyme B, a distinct receptor repertoire, with lower levels of CD160 and CD31 and higher levels of CD55 and, remarkably, a higher expression of tissue-resident markers CD103 and the NK cell decidual marker CD9. Last of all, in individuals with severe disease, we identified an expansion of a CD151brightCD9+ NK cell subset, suggesting that these cells play a specific role in COVID-19. Altogether, our findings suggest that CD151+ NK cells may have a relevant role in COVID-19 immunopathogenesis.

Variable clinical presentation of hypomorphic DCLRE1C deficiency from childhood to adulthood.

In this study, we aimed to report long-term follow-up of our pediatric and adult patients with DCLRE1C (DNA cross-link repair 1C) hypomorphic mutation who were diagnosed leaky severe combined immunodeficiency (SCID). Eighteen patients (13 children and five adults), aged between 6 and 29 years were included. Clinical and immunological features, including immunoglobulin levels, T and B cells, natural killer cell subsets, regulator T (Treg) cell ratios/markers, and cytokines, were assessed before and after hematopoietic stem cell transplantation (HSCT) and compared with healthy controls. Recurrent infections (78%) and skin manifestations (61%) such as granulomatous skin lesions, warts, and vitiligo were the most common clinical findings. Autoimmune diseases were observed in 33% and malignancy in 17%. Most patients had low serum IgA and B- and T-cell lymphopenia at the first admission. Recent thymic emigrants (RTE), Tnaive, Bnaive, CD56dimCD16+ cell ratios were significantly lower in the patients than in control; however, follicular helper T TFH and Th1 [interferon gamma (IFN-γ)] cell ratios were significantly higher than the control. Although, Treg ratio and its functional receptors tend to be high but not significant. Eleven patients (61.1%) were treated with HSCT. Median follow-up times of transplant patients was 56 (9-67) months. Patients with hypomorphic DCLRE1C mutations may present with variable clinical and laboratory findings at different ages. Our study showed a helper T (Th)1-dominant immune response before and after HSCT. Increased IFN-γ and TFH cells ratio could be a reason of chronic inflammation and autoimmunity developing before and after HSCT. Long-term follow-up of these patients after HSCT will help to better understand the disease and its pathophysiology.

The Expression pattern of NK cells in systemic lupus erythematosus patients with different disease activities

Data demonstrated the role of natural killer (NK) cells in systemic lupus erythematosus (SLE). We aimed to determine the immunophenotype and frequency of NK cells and their subsets, CXCR3, CD161 expression in blood and renal tissue of SLE patients with and without lupus nephritis and their relationship with disease activity. The study included 31 SLE patients and 11 controls. Study participants underwent full history and thorough clinical examination. SLE patients underwent routine laboratory investigations. Renal tissue biopsies were taken from patients with lupus nephritis. The frequency of NK cell subsets in blood of patients and controls and renal tissue from patients was performed by flow cytometry. An increase in circulatory CD56bright NK cells and its CD56bright CD16dim subtype was associated with the severity of systemic manifestations in SLE patients. Total CD56bright NK cells and its CD56bright CD16bright subtypes in renal tissues were related to renal damage. We detected decreased CD161 expression on NK cells related to renal damage and severity of systemic manifestations in SLE patients. Decreased expression of CXCR3 on NK cell surface in renal tissues causes misdirected trafficking of NK cells that seems to reduce the severity of lupus nephritis. In conclusion, our results paved the way to understanding the role of NK cells in the pathogenesis of SLE which may represent a future target for immune therapy of SLE. NK and CD56dim subset were decreased in the blood and increased in renal tissue of SLE patients, while the CD56bright subset was increased in blood and decreased in renal tissue reflecting their effects on renal damage and severity of manifestations in SLE.

Feeder cell training shapes the phenotype and function of in vitro expanded natural killer cells.

Natural killer (NK) cells are candidates for adoptive cell therapy, and the protocols for their activation and expansion profoundly influence their function and fate. The complexity of NK cell origin and feeder cell cues impacts the heterogeneity of expanded NK (eNK) cells. To explore this, we compared the phenotype and function of peripheral blood-derived NK (PB-NK) and umbilical cord blood-derived NK (UCB-NK) cells activated by common feeder cell lines, including K562, PLH, and 221.AEH. After first encounter, most PB-NK cells showed degranulation independently of cytokines production. Meanwhile, most UCB-NK cells did both. We observed that each feeder cell line uniquely influenced the activation, expansion, and ultimate fate of PB eNK and UCB eNK cells, determining whether they became cytokine producers or killer cells. In addition, they also affected the functional performance of NK cell subsets after expansion, that is, expanded conventional NK (ecNK) and expanded FcRγ- NK (eg-NK)cells. Hence, the regulation of eNK cell function largely depends on the NK cell source and the chosen expansion system. These results underscore the significance of selecting feeder cells for NK cell expansion from various sources, notably for customized adoptive cell therapies to yield cytokine-producing or cytotoxic eNK cells.

Abnormal Immune Profile in Individuals with Kabuki Syndrome.

To analyze the lymphocyte subsets in individuals with Kabuki syndrome for better characterizing the immunological phenotype of this rare congenital disorder. We characterized the immunological profile including B-, T- and natural killer-cell subsets in a series (N = 18) of individuals with Kabuki syndrome. All 18 individuals underwent genetic analysis: 15 had a variant in KMT2D and 3 a variant in KDM6A. Eleven of the 18 individuals (61%) had recurrent infections and 9 (50%) respiratory infections. Three (17%) had autoimmune diseases. On immunological analysis, 6 (33%) had CD4 T-cell lymphopenia, which was preferentially associated with the KMT2D truncating variant (5/9 individuals). Eight of 18 individuals (44%) had a humoral deficiency and eight (44%) had B lymphopenia. We found abnormal distributions of T-cell subsets, especially a frequent decrease in recent thymic emigrant CD4 + naive T-cell count in 13/16 individuals (81%). The immunological features of Kabuki syndrome showed variable immune disorders with CD4 + T-cell deficiency in one third of cases, which had not been previously reported. In particular, we found a reduction in recent thymic emigrant naïve CD4 + T-cell count in 13 of 16 individuals, representing a novel finding that had not previously been reported.

Pulmonary Administration of TLR2/6 Agonist after Allergic Sensitization Inhibits Airway Hyper-Responsiveness and Recruits Natural Killer Cells in Lung Parenchyma.

Asthma is a chronic lung disease with persistent airway inflammation, bronchial hyper-reactivity, mucus overproduction, and airway remodeling. Antagonizing T2 responses by triggering the immune system with microbial components such as Toll-like receptors (TLRs) has been suggested as a therapeutic concept for allergic asthma. The aim of this study was to evaluate the effect of a TLR2/6 agonist, FSL-1 (Pam2CGDPKHPKSF), administered by intranasal instillation after an allergic airway reaction was established in the ovalbumin (OVA) mouse model and to analyze the role of natural killer (NK) cells in this effect. We showed that FSL-1 decreased established OVA-induced airway hyper-responsiveness and eosinophilic inflammation but did not reduce the T2 or T17 response. FSL-1 increased the recruitment and activation of NK cells in the lung parenchyma and modified the repartition of NK cell subsets in lung compartments. Finally, the transfer or depletion of NK cells did not modify airway hyper-responsiveness and eosinophilia after OVA and/or FSL-1 treatment. Thus, the administration of FSL-1 reduces airway hyper-responsiveness and bronchoalveolar lavage eosinophilia. However, despite modifications of their functions following OVA sensitization, NK cells play no role in OVA-induced asthma and its inhibition by FSL-1. Therefore, the significance of NK cell functions and localization in the airways remains to be unraveled in asthma.

Evaluation of the natural killer cell subsets and their relationship with serum interferon gamma and vitamin D levels in women with stages III and IV endometriosis: A case-control study.

Natural killer (NK) cells play a critical role in the pathogenesis of endometriosis. Moreover, a normal vitamin D level is remarkably associated with an optimal immune response. So, there may be a probable relationship between these factors and the endometriotic women. This study aimed to evaluate the percentage of NK cells and their subsets and their relationship with serum levels of vitamin D and interferon-gamma (IFN-γ) in women with endometriosis. In this case-control study, 29 women with stage III-IV endometriosis and 30 healthy controls were enrolled. The study was conducted in the Immunology Department of Isfahan University of Medical Sciences, Isfahan, Iran between November 2021 and June 2022. The percentage of NK cells and their subsets, including CD56 CD16 , CD56 CD16 and CD56 CD16 were measured in the peripheral blood samples using flow cytometry. Serum levels of vitamin D and IFN-γ were also measured using the enzyme-linked immunosorbent assay. The mean percentage of NK cells in women with endometriosis increased significantly compared to the control group (p = 0.03). The percentage of CD56 CD16 (p = 0.007) and CD56 CD16 (p = 0.043) increased significantly in women with endometriosis in comparison with the control group, but the percentage of CD56 CD16 subset was not significantly different. No relationship was observed between NK cells and their subsets with vitamin D and IFN-γ in the studied groups. The study of NK cell subsets and their related factors can be useful in assessing and treating women suffering from endometriosis. However, more comprehensive studies are required to draw definitive conclusions about these observations.

Single-cell transcriptomic analysis of retinal immune regulation and blood-retinal barrier function during experimental autoimmune uveitis

Uveitis is characterised by breakdown of the blood-retinal barrier (BRB), allowing infiltration of immune cells that mediate intraocular inflammation, which can lead to irreversible damage of the neuroretina and the loss of sight. Treatment of uveitis relies heavily on corticosteroids and systemic immunosuppression due to limited understanding of disease pathogenesis. We performed single-cell RNA-sequencing of retinas, as well as bulk RNA-sequencing of retinal pigment epithelial (RPE) cells from mice with experimental autoimmune uveitis (EAU) versus healthy control. This revealed that the Th1/Th17-driven disease induced strong gene expression changes in response to inflammation in rods, cones, Müller glia and RPE. In particular, Müller glia and RPE cells were found to upregulate expression of chemokines, complement factors, leukocyte adhesion molecules and MHC class II, thus highlighting their contributions to immune cell recruitment and antigen presentation at the inner and outer BRB, respectively. Additionally, ligand-receptor interaction analysis with CellPhoneDB revealed key interactions between Müller glia and T cell / natural killer cell subsets via chemokines, galectin-9 to P4HB/TIM-3, PD-L1 to PD-1, and nectin-2/3 to TIGIT signalling axes. Our findings elucidate mechanisms contributing to breakdown of retinal immune privilege during uveitis and identify novel targets for therapeutic interventions.

Kir6.1, a component of an ATP-sensitive potassium channel, regulates natural killer cell development.

Involved in immunity and reproduction, natural killer (NK) cells offer opportunities to develop new immunotherapies to treat infections and cancer or to alleviate pregnancy complications. Most current strategies use cytokines or antibodies to enhance NK-cell function, but none use ion channel modulators, which are widely used in clinical practice to treat hypertension, diabetes, epilepsy, and other conditions. Little is known about ion channels in NK cells. We show that Kcnj8, which codes for the Kir6.1 subunit of a certain type of ATP-sensitive potassium (K ATP ) channel, is highly expressed in murine splenic and uterine NK cells compared to other K + channels previously identified in NK cells. Kcnj8 expression is highest in the most mature subset of splenic NK cells (CD27 - CD11b + ) and in NKG2A + or Ly49C/I + educated uterine NK cells. Using patch clamping, we show that a subset of NK cells expresses a current sensitive to the Kir6.1 blocker PNU-37883A. Kcnj8 does not participate in NK cell degranulation in response to tumor cells in vitro or rejection of tumor cells in vivo . Transcriptomics show that genes previously implicated in NK cell development are amongst those differentially expressed in CD27 - CD11b + NK cells deficient of Kcnj8 . Indeed, we found that mice with NK-cell specific Kcnj8 gene ablation have fewer CD11b + CD27 - and KLRG-1 + NK cells in the bone barrow and spleen. These results show that the K ATP subunit Kir6.1 has a key role in NK-cell development.

Day 100 Recovery of Absolute Number of Inhibitory KIR2DL2 and Activating NKp30 Natural Killer Cells Predicts Survival Post-Autologous Stem Cell Transplantation in Lymphomas.

The infusion autograft absolute number of inhibitory killer immunoglobulin-like receptor (KIR) 2DL2 and activating natural killer (NK)p30 cells are predictors of clinical outcomes in lymphoma patients undergoing autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT). To assess if the long-term recovery of these NK cell subsets still holds clinical relevance, we set up to investigate their prognostic ability at day 100 post-APBHSCT. This was a retrospective single-institution study including 107 patients from our prior phase III trial who had a clinical assessment at day 100 post-APBHSCT. The median follow-up from day 100 was 168.19 months (interquartile range: 156.85-181.28 months). Patients with day 100 inhibitory KIR2DL2 < 0.08 cells/µL and activating NKp30 ≥ 0.19 cells/µL experienced superior overall survival (OS) and progression-free survival (PFS). A multivariate analysis revealed both the day 100 inhibitory KIR2DL2 [OS: HR = 1.449, 95%CI, 1.231-1.895, p < 0.013; and PFS: HR = 2.069, 95%CI, 1.134-3.775, p < 0.021] and activating NKp30 [OS: HR = 4.985, 95%CI, 2.614-9.506, p < 0.0001; and PFS: HR = 4.661, 95%CI, 2.598-8.393, p < 0.0001] were independent predictors for OS and PFS. Inhibitory KIR2DL2 and activating NKp30 NK cells at day 100 are prognostic immune biomarkers in lymphoma patients treated with APBHSCT.

14 Natural killer cells have impaired cytotoxicity in advanced renal cell carcinoma

Abstract Background Natural killer (NK) cells are key mediators of anti-tumor activity in multiple cancers, including clear cell renal cell carcinoma (ccRCC). However, the phenotype and function of NK cells across different disease stages of ccRCC is incompletely characterized. Methods Single-cell RNA (scRNA)-sequencing (10x Genomics) data from tumor and adjacent normal kidney from ccRCC was analyzed at multiple clinical stages (localized – stage I/II/III; and advanced – stage IV). Graph-based clustering and lineage markers were used to identify distinct NK cell populations. Differential gene expression analysis was performed to further investigate NK cell phenotype and to derive a gene expression signature (GES). Gene signatures from NK cell subclusters of interest were used to interrogate bulk transcriptomic datasets and expression with clinical outcomes. Tumor-infiltrating NK cell function (cytokine production and cytotoxicity) was assessed by isolation of live NK cells from ccRCC tissue, co-culture with K562 target cells, and measurement of cytokine (IFNgamma) and cytotoxicity (CD107a) markers by flow cytometry. Results Single-cell transcriptomic data were analyzed from 13 patients with ccRCC (tumor and normal kidney), resulting in 21,139 high-quality NK cells. Patients with advanced/metastatic RCC had a lower proportion of NK cells versus total immune cells in the tumor microenvironment compared to normal kidney (p=0.036) and localized ccRCC (p=0.088). Clustering analysis revealed 6 distinct NK cell subsets. The C0.Bright-like NK cell cluster was significantly enriched in advanced ccRCC compared to localized ccRCC (p=0.048) and normal kidney (p=0.0059), expressed markers of tissue residency (ZNF683, ITGA1, CD9, ITGAE), and had decreased expression of cytotoxicity genes (GZMB, PRF1). A GES signature composed of genes upregulated in the dysfunctional C0.Bright-like NK cell cluster was used to interrogate bulk RNA-sequencing data from The Cancer Genome Atlas clear cell cohort, providing validation in a large, independent cohort, of an increase in this dysfunctional NK subset in advanced ccRCC compared to localized ccRCC (p=0.00039) and normal tissue (p=5.3e-05). To functionally confirm the decreased cytotoxicity of this dysfunctional NK population, CD45+CD56+CD3- NK cells were isolated from advanced ccRCC, and co-cultured with K562 target cells. Consistent with the transcriptomic phenotype, tumor-resident CD49a+CD9+ NK cells had cytokine production (IFNgamma) but decreased markers of cytotoxicity (CD107a) compared to CD49a-CD9- NK cells. By contrast, CD49a+CD9+ NK cells isolated from peripheral blood or normal kidney tissue maintained cytotoxic activity. Conclusions Among patients with ccRCC, a single-cell transcriptomic analysis revealed heterogeneous NK cell populations. A dysfunctional tumor resident NK cell phenotype was enriched among patients with advanced disease in ccRCC, and functionally confirmed to have diminished cytotoxicity. This study therefore provides insight into a new axis of immune dysfunction – decreased NK-mediated cytotoxicity – in advanced ccRCC. An improved understanding of NK cell dysfunction within ccRCC may provide a foundation for therapeutic restoration of NK-mediated anti-tumor activity in ccRCC. DOD CDMRP Funding: yes

Accumulation of CD56+ CD16- Natural Killer Cells in Response to Preoperative Chemotherapy for Breast Cancer.

The activation of the antitumor immune responses of T cells and natural killer (NK) cells is important to induce breast tumor shrinkage via preoperative chemotherapy. We evaluated how antitumor immune responses contribute to the effects of such therapy. Forty-three patients with stages I - IV breast cancer who underwent surgery between August 2018 and Jun 2023 after preoperative chemotherapy were enrolled. Peripheral natural killer (pNK) cell activity was assessed by 51Cr-release assay, and the counts and percentages of CD4+, CD8+, and NK cells and their subsets in peripheral blood were measured before and after chemotherapy by two-color flow cytometry. Associations of cell population changes with chemotherapy responses were analyzed. On univariate analysis, relative to grade (G) ≤ 1 effects, G ≥ 2 therapeutic effects were associated significantly with human epidermal growth factor receptor 2 (HER-2)+ breast cancer (P = 0.024) and post-chemotherapy CD56+ CD16- NK cell accumulation (8.4% vs. 5.5%, P = 0.042), and tended to be associated with increased pre-chemotherapy CD56+ CD16- NK cell percentages (5.4% vs. 3.3%, P = 0.054) and pNK cell activity (42.0% vs. 34.5%, P = 0.057). The accumulation and increased percentage of CD56+ CD16- NK cells in patients with G ≥ 2 effects were not associated with changes in pNK cell activity or the disappearance of axillary lymph-node metastases. On multivariate analysis, G ≥ 2 therapeutic effects tended to be associated with higher pre-chemotherapy pNK levels (odds ratio = 0.96; 95% confidence interval: 0.921 - 1.002; P = 0.067). The accumulation of the immunoregulatory CD56+ CD16- NK cell subset in the peripheral blood before and after chemotherapy may lead to the production of cytokines that induce an antitumor immune response. Activation of the immune response mediated by CD56+ CD16- pNK cells after chemotherapy and their high counts before chemotherapy may contribute to the improvement of therapeutic effects against breast cancer.

Single-cell profiling identifies a CD8bright CD244bright Natural Killer cell subset that reflects disease activity in HLA-A29-positive birdshot chorioretinopathy

Birdshot chorioretinopathy is an inflammatory eye condition strongly associated with MHC-I allele HLA-A29. The striking association with MHC-I suggests involvement of T cells, whereas natural killer (NK) cell involvement remains largely unstudied. Here we show that HLA-A29-positive birdshot chorioretinopathy patients have a skewed NK cell pool containing expanded CD16 positive NK cells which produce more proinflammatory cytokines. These NK cells contain populations that express CD8A which is involved in MHC-I recognition on target cells, display gene signatures indicative of high cytotoxic activity (GZMB, PRF1 and ISG15), and signaling through NK cell receptor CD244 (SH2D1B). Long-term monitoring of a cohort of birdshot chorioretinopathy patients with active disease identifies a population of CD8bright CD244bright NK cells, which rapidly declines to normal levels upon clinical remission following successful treatment. Collectively, these studies implicate CD8bright CD244bright NK cells in birdshot chorioretinopathy.