Normal Natural Killer Research Articles

Decreased Peripheral Blood Natural Killer Cell Count in Untreated Juvenile Dermatomyositis Is Associated with Muscle Weakness.

Juvenile Dermatomyositis (JDM) is the most common inflammatory myopathy in pediatrics. This study evaluates the role of Natural Killer (NK) cells in Juvenile Dermatomyositis (JDM) pathophysiology. The study included 133 untreated JDM children with an NK cell count evaluation before treatment. NK cell subsets (CD56low/dim vs. CD 56bright) were examined in 9 untreated children. CD56 and perforin were evaluated in situ in six untreated JDM and three orthopedic, pediatric controls. 56% of treatment-naive JDM had reduced circulating NK cell counts, designated "low NK cell". This low NK group had more active muscle disease compared to the normal NK cell group. The percentage of circulating CD56low/dim NK cells was significantly lower in the NK low group than in controls (0.55% vs. 4.6% p < 0.001). Examination of the untreated JDM diagnostic muscle biopsy documented an increased infiltration of CD56 and perforin-positive cells (p = 0.023, p = 0.038, respectively). Treatment-naive JDM with reduced circulating NK cell counts exhibited more muscle weakness and higher levels of serum muscle enzymes. Muscle biopsies from treatment-naive JDM displayed increased NK cell infiltration, with increased CD56 and perforin-positive cells.

Peripheral NK cells identified as the predictor of response in extensive-stage small cell lung cancer patients treated with first-line immunotherapy plus chemotherapy.

Although immunotherapy improves outcomes in extensive-stage small-cell lung cancer (ES-SCLC), the search for biomarkers predicting treatment success is crucial. Natural killer (NK) cells are potential indicators in various cancers, however, their precise role in ES-SCLC prognosis remains unclear. In this retrospective study, 33 patients with ES-SCLC treated with first-line immuno-chemotherapy were enrolled. The peripheral NK cell percentage and its longitudinal dynamics were analyzed using flow cytometry. Progression-free survival (PFS) and overall survival (OS) were calculated as hazard ratio (HR) and compared statistically. The median PFS was better in the group with normal baseline NK cell levels than the low group (7.0 vs. 4.6months; HR = 0.17; 95% CI 0.07-0.41; P < 0.0001), but there was no association with OS (14.9 vs. 10.3months; HR = 0.55; 95% CI 0.23-1.31; P = 0.171). Furthermore, the NK cell% for 95.0% of patients increased after immunochemotherapy in the clinical response group (P = 0.0047), which led to a better median PFS (6.3 vs. 2.1months; HR = 0.23; 95% CI 0.05-0.98; P < 0.0001) and OS (14.9 vs. 5.9months; HR = 0.20; 95% CI 0.04-1.02; P < 0.0001). Similar trends were observed with NK cell% changes up to disease progression, improving PFS (6.5 vs. 4.3; HR = 0.41; 95% CI 0.12-0.92; P = 0.0049) and OS (17.4 vs. 9.7; HR = 0.42; 95% CI 0.17-1.02; P < 0.0001). In patients with ES-SCLC, the percentage and changes in peripheral NK cells can predict the response to combined immunotherapy and chemotherapy.

IKAROS and AIOLOS directly regulate AP-1 transcriptional complexes and are essential for NK cell development.

Ikaros transcription factors are essential for adaptive lymphocyte function, yet their role in innate lymphopoiesis is unknown. Using conditional genetic inactivation, we show that Ikzf1/Ikaros is essential for normal natural killer (NK) cell lymphopoiesis and IKZF1 directly represses Cish, a negative regulator of interleukin-15 receptor resulting in impaired interleukin-15 receptor signaling. Both Bcl2l11 and BIM levels, and intrinsic apoptosis were increased in Ikzf1-null NK cells, which in part accounts for NK lymphopenia as both were restored to normal levels when Ikzf1 and Bcl2l11 were co-deleted. Ikzf1-null NK cells presented extensive transcriptional alterations with reduced AP-1 transcriptional complex expression and increased expression of Ikzf2/Helios and Ikzf3/Aiolos. IKZF1 and IKZF3 directly bound AP-1 family members and deletion of both Ikzf1 and Ikzf3 in NK cells resulted in further reductions in Jun/Fos expression and complete loss of peripheral NK cells. Collectively, we show that Ikaros family members are important regulators of apoptosis, cytokine responsiveness and AP-1 transcriptional activity.

Cytokine Storm and Sepsis-Induced Multiple Organ Dysfunction Syndrome.

There is extensive overlap of clinical features among familial or primary HLH (pHLH), reactive or secondary hemophagocytic lymphohistiocytosis (sHLH) [including macrophage activation syndrome (MAS) related to rheumatic diseases], and hyperferritinemic sepsis-induced multiple organ dysfunction syndrome (MODS); however, the distinctive pathobiology that causes hyperinflammatory process in each condition requires careful considerations for therapeutic decision-making. pHLH is defined by five or more of eight HLH-2004 criteria [1], where genetic impairment of natural killer (NK) cells or CD8+ cytolytic T cells results in interferon gamma (IFN-γ)-induced hyperinflammation regardless of triggering factors. Cytolytic treatments (e.g., etoposide) or anti-IFN-γ monoclonal antibody (emapalumab) has been effectively used to bridge the affected patients to hematopoietic stem cell transplant. Secondary forms of HLH also have normal NK cell number with decreased cytolytic function of varying degrees depending on the underlying and triggering factors. Although etoposide was uniformly used in sHLH/MAS in the past, the treatment strategy in different types of sHLH/MAS is increasingly streamlined to reflect the triggering/predisposing conditions, severity/progression, and comorbidities. Accordingly, in hyperferritinemic sepsis, the combination of hepatobiliary dysfunction (HBD) and disseminated intravascular coagulation (DIC) reflects reticuloendothelial system dysfunction and defines sepsis-associated MAS. It is demonstrated that as the innate immune response to infectious organism prolongs, it results in reduction in T cells and NK cells with subsequent lymphopenia even though normal cytolytic activity continues (Figs. 30.1, 30.2, 30.3, and 30.4). These changes allow free hemoglobin and pathogens to stimulate inflammasome activation in the absence of interferon-γ (IFN-γ) production that often responds to source control, intravenous immunoglobulin (IVIg), plasma exchange, and interleukin 1 receptor antagonist (IL-1Ra), similar to non-EBV, infection-induced HLH.

Extracellular vesicles derived from immortalized human natural killer cell line NK3.3 as a novel therapeutic for multiple myeloma.

Over the last decade, there have been many advancements in the therapeutic treatment of multiple myeloma (MM), including the use of natural killer (NK) cells. However, despite promising results from clinical trials, there are concerns over the use of NK cell-based therapy. Cells often undergo growth arrest, limiting their experimental utility; donor cells are extremely heterogeneous, resulting in content variability; and patients receiving allogeneic cells are at risk for graft-versus-host disease and/or cytokine release syndrome. Extracellular vesicles (EVs) have emerged as a new natural therapeutic tool. EVs are known to carry cargo derived from the parent cell from which they originate. NK cells play an important role in the innate immune system, targeting and killing tumor cells. This has led many researchers to isolate EVs from NK cells for their cytotoxic potential. In this study, we isolated EVs from the NK cell line, NK3.3, which was derived from the peripheral blood of a healthy donor. Currently, it is the only normal human NK cell line reported with all the functional characteristics of healthy NK cells. To address the issue of growth arrest, we immortalized NK3.3 cells with lentivirus encoding the catalytic subunit of human telomerase htert (NK3.3-LTV). EVs from these cells were isolated using a modified polyethylene glycol (PEG)-acetate precipitation protocol to simplify processing and increase EV yield. We demonstrated that NK3.3-LTV EVs target both sensitive and drug-resistant MM cell lines as well as primary patient MM cells in vitro, decreasing proliferation and inducing apoptotic cell death as well as or better than EVs from non-immortalized cells with no toxicity towards normal cells. This study is the first step towards developing an immunotherapeutic product designed to treat patients with relapsed/refractory MM.

CAR-NK Cells Generated with mRNA-LNPs Kill Tumor Target Cells In Vitro and In Vivo.

Natural killer (NK) cells are cytotoxic lymphocytes that are critical for the innate immune system. Engineering NK cells with chimeric antigen receptors (CARs) allows CAR-NK cells to target tumor antigens more effectively. In this report, we present novel CAR mRNA-LNP (lipid nanoparticle) technology to effectively transfect NK cells expanded from primary PBMCs and to generate functional CAR-NK cells. CD19-CAR mRNA and BCMA-CAR mRNA were embedded into LNPs that resulted in 78% and 95% CAR expression in NK cells, respectively. BCMA-CAR-NK cells after transfection with CAR mRNA-LNPs killed multiple myeloma RPMI8226 and MM1S cells and secreted IFN-gamma and Granzyme B in a dose-dependent manner in vitro. In addition, CD19-CAR-NK cells generated with CAR mRNA-LNPs killed Daudi and Nalm-6 cells and secreted IFN-gamma and Granzyme B in a dose-dependent manner. Both BCMA-CAR-NK and CD19-CAR-NK cells showed significantly higher cytotoxicity, IFN-gamma, and Granzyme B secretion compared with normal NK cells. Moreover, CD19-CAR-NK cells significantly blocked Nalm-6 tumor growth in vivo. Thus, non-viral delivery of CAR mRNA-LNPs can be used to generate functional CAR-NK cells with high anti-tumor activity.

#3255 BETA2 MICROGLOBULIN IS AN INDEPENDENT PARAMETER RELATED WITH DYSFUNCTION OF NATURAL KILLER CELL ACTIVITY IN HEMODIALYSIS PATIENTS

Abstract Background and Aims End-stage renal disease patients are characterized by immune dysfunction. Natural killer (NK) cells area lymphocytes of innate immune system that play a key role in an immune response towards viral infections and tumors. We aimed to analyze clinical factors related to the NK cell activity in chronic hemodialysis (HD) patients. Method Clinically stable 196 patients who were treated by HD for more than 3 months were enrolled from 4 outpatient HD clinics. NK cell activity was assessed using NK Vue assay (NKMAX, Sungnam, Korea) that uses serum of ex-vivo stimulated whole blood to detect interferon (IFN)-γ secreted from NK cells as an indicator of NK cell activity. All patients were stratified as abnormal (&amp;lt;250 pg/ml) and normal (≥250 pg/ml) groups according to NK cell activity. Results Mean age of the HD patients was 62.7 years [range 31 to 95 years] and mean HD duration was 49.2 months [range 3 to 221 months]. In total, 68 (35%) of HD patients showed abnormal NK cell activity. The abnormal NK cell activity group showed significantly increased age and shorter HD duration compared to the normal NK cell activity group (66.7 ± 11.9 vs. 60.6 ± 13.4 years, p = 0.001; 33.8 ± 33.0 vs. 57.5 ± 48.5 months, p&amp;lt;0.001, respectively). The serum albumin and parathyroid hormone levels were significantly lower in the abnormal NK cell activity group (3.7 ± 0.4 vs. 3.9 ± 0.3 g/dL, p = 0.005 and 176 ± 153 vs. 240 ± 260 pg/mL, respectively). In contrast, hemoglobin, blood urea nitrogen, urea reduction ratio, and C-reactive protein levels were comparable between the two groups. In multivariate regression analysis, old age, short dialysis duration, low serum albumin and high beta2 microglobulin levels were independent risk factors of abnormal NK cell activity in HD patients (adjusted odd ratio [AOR], 1.033; 95% confidence interval [CI], 1.005-1.062, p = 0.02; AOR, 0.981; 95% CI, 0.971-0.992; p&amp;lt;0.001, AOR, 0.395; 95% CI, 0.157-0.995; p = 0.049, and AOR, 1.042; 95% CI, 1.011-1.075; p = 0.008, respectively). Conclusion Our results suggest that young age and good nutrition as well as lower burden of middle molecule uremic toxin is associated with greater NK cell activity in HD patients.

Harnessing the power of memory-like NK cells to fight cancer.

Natural killer (NK) cells possess the innate ability to eliminate cancerous cells effectively. Their crucial role in immunosurveillance has been widely recognized and exploited for therapeutic intervention. Despite the fast-acting nature of NK cells, NK adoptive cell transfer lacks favorable response in some patients. Patient NK cells often display diminished phenotype in preventing cancer progression resulting in poor prognosis. Tumor microenvironment plays a significant role in causing the downfall of NK cells in patients. The release of inhibitory factors by tumor microenvironment hinders normal function of NK cells against tumor. To overcome this challenge, therapeutic strategies such as cytokine stimulation and genetic manipulation are being investigated to improve NK tumor-killing capacity. One of the promising approaches includes generation of more competent NK cells via ex vivo cytokines activation and proliferation. Cytokine-induced ML-NK demonstrated phenotypic alterations such as enhanced expression of activating receptors which help elevate their antitumor response. Previous preclinical studies showed enhanced cytotoxicity and IFNγ production in ML-NK cells compared to normal NK cells against malignant cells. Similar effects are shown in clinical studies in which MK-NK demonstrated encouraging results in treating hematological cancer. However, there is still a lack of in-depth studies using ML-NK in treating different types of tumors and cancers. With convincing preliminary response, this cell-based approach could be used to complement other therapeutic modalities to achieve better clinical outcomes.

Factors Affecting Natural Killer Cell Recovery after Autologous Stem Cell Transplantation in Multiple Myeloma

Introduction:Natural killer (NK) cells are large granular lymphocytes, very potent effector lymphocytes that can induce cytotoxicity against a vast array of tumors without the need for antigen sensitization or antigen presentation by MHC class I. NK cells are believed to play important role in immune surveillance for cancer, limiting neoplastic progression, and effectors of anti-tumor therapies -by introducing Abs that block NK cell inhibitory receptors yielding improved NK cell-mediated lysis-Retrospective studies demonstrated a significant correlation of NK cell recovery after autologous stem cell transplantation (ASCT) in multiple myeloma (MM) and disease outcomes. Higher absolute NK cell count one month after ASCT is associated with longer progression-free survival (PFS) and decreased risk of relapse. We aimed at investigating factors affecting NK cell recovery after ASCT in patients with multiple myeloma.Method:We designed a prospective cohort study, evaluating the potential factors that could affect NK cell recovery after ASCT. We included participants undergoing frontline ASCT for MM. We excluded participants with non-secretory myeloma or other malignancies that require active treatment, or with autoimmune disorders.All participants received conditioning regimen consisted of melphalan 200 mg/m2 on day -2. In patients older than 65 years old given 100mg/m2 for 2 days. Dose reduction to 140 mg/m2 for patients with serum creatinine > 2.0 mg/dL. Hematopoietic growth factor (peg-filgrastim 6 mg once subcutaneously) was given on day +1.Absolute NK cell count (CD3-, CD56+ cells) was determined using flow cytometric immunophenotyping of peripheral blood two-three months after ASCT. To determine variables that affected NK cell recovery after ASCT, absolute NK cell count was dichotomized to less than the lower limit of normal “NK < 76” and normal “NK > or equal 76” following institutional normal reference range which is consistent with ARUP NK cell enumeration reference. Statistical analysis was performed using Fisher-Exact test for categorical variable and Wilcoxon rank test for continuous variables.Results:We analyzed the results of fifteen patients treated with frontline ASCT for multiple myeloma. With a median age at diagnosis of 60 years, ranging from 47 - 70 years. Of which 53 percent females and 47 percent males. Patients' baseline characteristics are described in Table 1Our data showed that 63 percent of patients with post-transplantation ALC > 1000 (5 of 8 patients), and 73 percent for ALC > 500, (8 of 11 patients), had normal absolute NK cell count; with a correlation coefficient of 0.3 (Pearson Correlation Coefficients), suggesting a moderate linear correlation between absolute NK cell count and ALC two-three months after ASCT.Patients' gender, age at ASCT, and comorbidity index (SORROR score) did not differ between the two groups of patients, P-value= 0.6193, 0.8454, 0.1721, respectively. Additionally, disease burden at the time of diagnosis, presence of CRAB criteria, involved free light chain and monoclonal immunoglobulins; all did not differ between the two cohorts. (Table 2)Medications received before ASCT did affect the absolute NK cell count with a higher proportion of normal absolute NK cell count, and higher mean absolute NK cell in the cohort received double-class (PI plus IMiDs) when compared to triple-class (PI plus IMiDs plus Anti-CD 38 mAb) therapy before transplantation (mean NK cell count 125 and 53 Cell/μL, respectively), with marginal statistical significance P-value= 0.0667 (Fisher's Exact Test).Discussion:Our study showed that the addition of anti-CD38 mAb to myeloma induction regimen, associated with compromised NK cell recovery. Casneuf et al reported similar findings, in daratumumab-treated myeloma patients, total and activated NK-cell counts reduced rapidly in peripheral blood after the first dose, remained low throughout treatment, and recovered after treatment ended. Similar reductions were observed in the bone marrow.Conclusion:Medications received before transplantation potentially affect NK cell recovery in multiple myeloma patients. Although, the addition of anti-CD38 mAb to the myeloma induction regimen is associated with deeper response, its impact on immune reconstitution needs to be investigated on a larger sample size. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Hepatic Niche Leads to Aggressive Natural Killer Cell Leukemia Proliferation

Aggressive natural killer cell leukemia (ANKL) is a rare form of natural killer (NK)-cell neoplasm with median survival of less than 2 months. Recently, the genomic mutation analysis using tumor cells reveled that the mutational profile of ANKL was similar to that of extranodal NK / T-cell lymphoma, which has relatively better prognosis than ANKL, explaining no causative mutations with a dismal prognosis. Here, using patient-derived xenograft model (PDX) mouse, we show that hepatic niche plays an important role in the ANKL biology.We established PDX mouse by intravenously injecting ANKL cells derived from patient peripheral blood or bone marrow samples to immunocompromised mice, which enables comprehensive analysis for tumor cells as well as tumor microenvironment. In total, we obtained four PDX strains derived from different patients. Time series pathological and flowcytometric analyses revealed that the ANKL cells initially engrafted and proliferated in sinusoidal or peri-portal area of the liver. This sinusoid or peri-portal distribution of ANKL in the liver was also confirmed with the patient liver specimen.To further determine the feature of ANKL in the liver, we selected liver or spleen tropic cells by serial adaptive transfer from each organ to the next mice. The liver-tropic ANKL cells proliferated more rapidly than splenic ANKL cells, which was evident by the significantly shorter survival of PDX mice injected liver-tropic cells (Figure). We performed RNA-sequencing using liver-tropic ANKL cells, spleen-tropic ANKL cells and NK-cells derived from healthy donors. These three types of cells showed distinct populations in principal component analysis. To further clarify the interaction between ANKL and liver niche, we performed additional RNA sequencing using total liver of mouse with or without bearing leukemic cells. In the cell-cell interaction analysis, we used two computational methods, mixed-species RNA-seq (Komura, et al. BMC Genomics 2016), which can distinguish transcripts derived from human (cancer) with mouse (non-cancer niche cells), and NicheNet (Browaeys, et al. Nat Methods 2020), which is a computational algorithm to model intercellular communication by linking ligands to target genes. These two methods allowed us to investigate the interaction between liver niche ligands and ANKL receptors.Among the listed ligand-receptor interactions, we focused on the macrophage migration inhibitory factor (MIF) and its receptor, CD74 axis. While CD74 was upregulated in ANKL cells compared with normal NK cells, MIF was highly expressed in the liver mainly liver sinusoid and Kupffer cells. Although we failed to culture primary ANKL cells in vitro, ANKL cells treated with MIF showed improved viability in vitro compared with untreated cells. Deletion of CD74 on the ANKL cells using CRISPR-Cas9 system attenuated the tumor formation in the liver as well as in bone marrow and spleen of PDX mouse compared with the wild type ANKL cells. These findings highlight that the liver, non-canonical hematopoietic organ in adults, is a principal niche where the liver specific components are required for survival and proliferation of ANKL cells. MIF-CD74 axis might play an important role in the communication between ANKL and hepatic niche. [Display omitted] DisclosuresKanda: Otsuka Pharmaceutical: Honoraria, Research Funding; Sanofi: Research Funding; MSD: Honoraria.

Down-regulation of PR/SET domain 10 underlies natural killer cell dysfunction in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the world's leading cause of tumor-related mortalities. Natural killer (NK) cells play a critical role at the first immunological defense line against HCC initiation and progression. NK cell dysfunction is therefore an important mechanism for immune evasion of HCC cells. In the present study using a murine HCC model, we revealed the down-regulation of PR/SET Domain 10 (PRDM10) in hepatic NK cells that were phenotypically and functionally exhausted. PRDM10 silencing diminished the expression of natural killer group 2 member D (NKG2D) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), augmented Tcellimmunoglobulin and ITIM domain (TIGIT) expression, and decreased the expression of interferon (IFN)-γ, perforin and granzyme B in normal hepatic NK cells in vitro. Consistently, PRDM10-deficient NK cells exhibited impaired cytotoxicity on target cells. In contrast, PRDM10 over-expression promoted NKG2D and Fas ligand(FasL) expression, reduced CD96 expression and enhanced transcripts of IFN-γ, perforin and granzyme B in NK cells in vivo. Moreover, PRDM10 silencing and PRDM10 over-expression down-regulated and up-regulated Eomesodermin (Eomes) expression, respectively. In summary, this study reveals PRDM10 down-regulation as a novel mechanism underlying NK cell dysfunction and identifies PRDM10 as a supporting factor of NK cell function.

Finding the best haematopoietic stem cell transplant regimen for GATA2 haploinsufficiency: how close are we?

Finding the best haematopoietic stem cell transplant regimen for GATA2 haploinsufficiency: how close are we?

Extracellular Vesicles From the Human Natural Killer Cell Line NK3.3 Have Broad and Potent Anti-Tumor Activity.

Natural killer (NK) cells are critical mediators of immune function, responsible for rapid destruction of tumor cells. They kill primarily through the release of granules containing potent cytolytic molecules. NK cells also release these molecules within membrane-bound exosomes and microvesicles – collectively known as extracellular vesicles (EV). Here we report the characterization and anti-tumor function of EVs isolated from NK3.3 cells, a well described clonal normal human NK cell line. We show that NK3.3 EVs contain the cytolytic molecules perforin, granzymes A and B, and granulysin, and an array of common EV proteins. We previously reported that the E3 ubiquitin ligase, natural killer lytic-associated molecule (NKLAM), is localized to NK granules and is essential for maximal NK killing; here we show it is present in the membrane of NK3.3 EVs. NK3.3-derived EVs also carry multiple RNA species, including miRNAs associated with anti-tumor activity. We demonstrate that NK3.3 EVs inhibit proliferation and induce caspase-mediated apoptosis and cell death of an array of both hematopoietic and non-hematopoietic tumor cell lines. This effect is tumor cell specific; normal cells are unaffected by EV treatment. By virtue of their derivation from a healthy donor and ability to be expanded to large numbers, NK3.3 EVs have the potential to be an effective, safe, and universal immunotherapeutic agent.

Malignant NK Cells from EBV(+) Human Extranodal NK/T Cell Lymphoma Exhibit Features of a Distinct NK Cell Developmental Subset Found in Mucosal Associated Lymphoid Tissue

Extranodal natural killer (NK)/T cell lymphoma, nasal type (ENKTL) is an aggressive, rare form of Epstein-Barr virus (EBV)-positive non-Hodgkin lymphoma that typically presents in the naso/oropharynx and is associated with high rates of systemic relapse and poor survival. The neoplastic cells in ENKTL are usually of NK cell origin, yet how they relate to the distinct stages that define normal NK cell development has not been fully described. We have established a model of human NK cell development where early NK cell precursors progress through sequential stages of maturation within mucosal associated lymphoid tissues (MALT) and are terminally differentiated in the peripheral blood (PB) (Freud et al. Cell Reports, 2016). Here we aimed to characterize neoplastic NK cells from ENKTL patients within this NK cell developmental framework.In this study we performed flow cytometry analyses, genome-wide DNA methylation profiling, and RNA sequencing of normal NK cell developmental subsets from 12 healthy donor PB and 12 tonsil specimens and of neoplastic NK cells from PB, bone marrow (BM), or cerebrospinal fluid of 11 patients with relapsed ENKTL. While all 11 of the samples contained NK cells, four of the 11 ENKTL patient samples contained distinctly abnormal NK cell populations that expressed CD56 and CD94 but lacked CD16, CD57, and NKp80. We noted that the recurring CD16(-)CD56(+)CD57(-)CD94(+)NKp80(-) phenotype of these cells was similar to that of MALT-resident “stage 4a” NK cell precursors that are rarely detected in the PB (Figure 1).To further investigate the ENKTL phenotype, we sorted two of the abnormal patient-derived CD16(-)CD56(+)CD57(-)CD94(+)NKp80(-) NK cell populations to >98% purity. Real-time quantitative PCR for the EBNA1 gene confirmed that the sorted cells were EBV(+). We then compared the ENKTL cells to normal NK cell developmental intermediates from healthy donors using genome-wide DNA methylation profiling and global gene expression analysis by RNA sequencing. DNA methylation analyses of human tonsil- and PB-derived NK cell developmental subsets revealed a broad, stage-wise acquisition of an NK cell-specific epigenetic program involving targeted gain and loss of methylation enriched in promoters and enhancer regions of genes with known relevance for NK cell development and function. Hypomethylation during development was found to be highly associated with T-BET, EOMES, ETS, KLF and RUNX family transcription factor binding sites, whereas hypermethylation was associated with RORγt, NFkB, and TCF/E2A (P <1x10-10). Expression of specific transcription factors and NK cell-related genes mirrored observed methylation changes. These analyses also revealed that the DNA methylation patterns of the purified ENKTL cells were most similar to those of MALT-derived stage 4a NK cells (Figure 2).Lastly, we transplanted purified ENKTL cells into immune deficient NOD- scid IL2Rgammanull mice. Whereas normal donor tonsil-derived stage 4a precursor cells underwent terminal differentiation in vivo, the transplanted ENKTL cells maintained the stage 4a-like phenotype and did not show evidence of terminal NK cell differentiation despite extensive expansion and infiltration of numerous organs. Global DNA methylation patterns also remained stable between the primary ENKTL cells and cells collected from the BMs and spleens of engrafted mice. Collectively, the flow cytometry, RNA expression, and epigenetic data show that the CD16(-)CD56(+)CD57(-)CD94(+)NKp80(-) ENKTL phenotype in the patient samples examined is stable and most similar to that of MALT-resident stage 4a NK cell precursors. These findings provide new insight into the biological nature of ENKTL that may guide development of novel therapeutic approaches for this aggressive disease. [Display omitted] DisclosuresBrammer:Celgene: Research Funding. Baiocchi:Prelude therapeutics: Research Funding; essanex: Research Funding; Theravectys: Consultancy; viracta: Membership on an entity's Board of Directors or advisory committees, Research Funding. Porcu:Kura: Research Funding; Miragen: Research Funding; Kiowa: Research Funding; Galderma: Research Funding; Innate Pharma: Research Funding; Tetralogic: Research Funding; Celgene: Research Funding; Cell Medica: Research Funding.

Activated natural killer cells predict poor clinical prognosis in high-risk B- and T-cell acute lymphoblastic leukemia

AbstractB- and T-cell acute lymphoblastic leukemia (B/T-ALL) may be refractory or recur after therapy by suppressing host anticancer immune surveillance mediated specifically by natural killer (NK) cells. We delineated the phenotypic and functional defects in NK cells from high-risk patients with B/T-ALL using mass cytometry, flow cytometry, and in silico cytometry, with the goal of further elucidating the role of NK cells in sustaining acute lymphoblastic leukemia (ALL) regression. We found that, compared with their normal counterparts, NK cells from patients with B/T-ALL are less cytotoxic but exhibit an activated signature that is characterized by high CD56, high CD69, production of activated NK cell–origin cytokines, and calcium (Ca2+) signaling. We demonstrated that defective maturation of NK cells into cytotoxic effectors prevents NK cells from ALL from lysing NK cell–sensitive targets as efficiently as do normal NK cells. Additionally, we showed that NK cells in ALL are exhausted, which is likely caused by their chronic activation. We found that increased frequencies of activated cytokine-producing NK cells are associated with increased disease severity and independently predict poor clinical outcome in patients with ALL. Our studies highlight the benefits of developing NK cell profiling as a diagnostic tool to predict clinical outcome in patients with ALL and underscore the clinical potential of allogeneic NK cell infusions to prevent ALL recurrence.

Natural Killer Cell Mobilization in Breast and Prostate Cancer Survivors: The Implications of Altered Stress Hormones Following Acute Exercise

Natural killer (NK) cells from the innate immune system are integral to overall immunity and also in managing the tumor burden during cancer. Breast (BCa) and prostate cancer (PCa) are the most common tumors in U.S. adults. Both BCa and PCa are frequently treated with hormone suppression therapies that are associated with numerous adverse effects including direct effects on the immune system. Regular exercise is recommended for cancer survivors to reduce side effects and improve quality of life. Acute exercise is a potent stimulus for NK cells in healthy individuals with current evidence indicating that NK mobilization in individuals with BCa and PCa is comparable. NK cell mobilization results from elevations in shear stress and catecholamine levels. Despite a normal NK cell response to exercise, increases in epinephrine are attenuated in BCa and PCa. The significance of this potential discrepancy still needs to be determined. However, alterations in adrenal hormone signaling are hypothesized to be due to chronic stress during cancer treatment. Additional compensatory factors induced by exercise are reviewed along with recommendations on standardized approaches to be used in exercise immunology studies involving oncology populations.

Evaluation of membrane bound IL-21 expanded natural killer cells for chronic lymphocytic leukemia therapy

Abstract Chronic lymphocytic leukemia (CLL) is the most prevalent adult leukemia and remains incurable despite recent therapeutic advances. Natural killer (NK) cells have potent anti-cancer effects, but efforts to use NK cell therapy in CLL have been limited by poor NK cell growth and anti-leukemia activity. We sought to determine if stimulating NK cells ex vivo with K562-based feeder cells expressing membrane-bound IL-21 (mbIL-21) (Denman et al., 2012) could overcome the limitations of prior techniques to create an effective therapy for CLL. Our data demonstrate that healthy donor-derived mbIL-21 expanded NK cells have increased antibody-dependent cellular cytotoxicity (ADCC) and direct cytotoxicity (DC; without targeting antibody) against CLL cell lines. This technique can also overcome CLL-induced NK suppression – CLL patient-derived NK cells expanded equally and were as potent as normal donor-derived NKs, including against both allogeneic and autologous CLL tumor cells. CLL tumor cells are not susceptible to DC but are very vulnerable to ADCC with anti-CD20 antibodies (rituximab or obinutuzumab). The lack of direct cytotoxicity of tumor cells was correlated to low NK:CLL quantitative conjugate formation, suggesting a lack of tumor target recognition. Blocking antibodies to FasL, TNFα, and TRAIL show that only TRAIL contributes modestly to anti-CLL tumor cytotoxicity, while application of folimycin demonstrates that perforin/granzyme release is the major mechanism of cytotoxicity. In vivo, treatment with expanded NK cells plus obinutuzumab significantly prolongs survival in the OSU-CLL human xenograft model. Based on these data, we are planning a clinical trial of mbIL-21 expanded NK cells plus obinutuzumab in CLL patients.

Adaptive Natural Killer Cell Functional Recovery in Hepatitis C Virus Cured Patients.

Current evidence suggests that dysfunctional natural killer (NK) cell responses during hepatitis C virus (HCV) infection can be restored after viral eradication with direct acting antivirals (DAAs). However, the fate of the recently described adaptive NK cell population, endowed with increased ability to mediate antibody-dependent cell-mediated cytotoxicity (ADCC), during HCV infection is poorly defined, while no study has explored the effects of DAAs on this NK subset. We performed multicolor flow cytometry to investigate CD57+ FcεRIγneg adaptive and FcεRIγpos conventional NK cell phenotype and function before and after DAA treatment in 59 patients chronically infected with HCV, 39 with advanced liver fibrosis, and 20 with mild-moderate liver fibrosis. Moreover, bulk NK cell phenotype and function were analyzed after cytokine activation following contact with K562 target cells. The proportion of FcεRIγneg NK cells in patients with HCV was associated with increased HCV load at baseline, and it was significantly reduced after treatment. Patients with an advanced fibrosis stage displayed increased NK cell activation and exhaustion markers that normalized after therapy. Of note, adaptive NK cells from patients with HCV were characterized by increased programmed death receptor 1 expression and reduced ADCC activity at baseline. DAA treatment restored ADCC ability and reduced programmed death receptor 1 expression. HCV profoundly affects the frequency, phenotype, and function of adaptive NK cells. DAA therapy restores a normal adaptive NK phenotype and enhances interferon-gamma production by this cell subset.

Abstract P213: Placental Ischemia-Stimulated Natural Killer Cells Contribute To Hypertension, Vascular Dysfunction, And Intrauterine Growth Restriction In Pregnant Rats

The Reduced Uterine Perfusion Pressure (RUPP) rat model of placental ischemia mimics many characteristics of preeclampsia (PE) such as hypertension (HTN), intrauterine growth restriction (IUGR), and increased cytolytic natural killer cells (cNKs). We have previously shown that natural killer (NK) cell depletion in RUPP rats improves PE pathophysiology and that RUPP NKs have a 5-fold increase in cytotoxicity vs normal pregnant NKs. In this study, we tested the hypotheses that (1) RUPP stimulated NKs play a direct role in causing HTN and IUGR in pregnant rats and (2) normal pregnant control (Sham) NKs attenuate HTN and IUGR in RUPP rats. NKs were isolated from the placentas of Sham and RUPP rats on gestation day (GD) 19. On GD14, vehicle or 5x10 6 RUPP NKs were infused i.v. into a subset of Sham rats, and vehicle or 5x10 6 Sham NKs were infused i.v. into a subset of RUPP rats. On GD18, Uterine Artery Resistance Index (UARI) was measured via Doppler Ultrasound; GD19, cNKs were quantified via flow cytometry and MAP, fetal weight, and blood were acquired. Plasma VEGF and sFlt-1 were measured via ELISA. Placental cNKs (% gated) increased from 3±1% in Sham to 19±5% in RUPP and 21±4% in Sham+RUPP NK (p&lt;0.05 vs Sham), and decreased to 3±1% in RUPP+Sham NK (p&lt;0.05 vs RUPP). Circulating cNKs also followed this trend. MAP increased from 102±1 mmHg in Sham to 130±2 mmHg in RUPP and 121±2 mmHg in Sham+RUPP NK (p&lt;0.05 vs Sham), and was blunted to 113±1 mmHg in RUPP+Sham NK (p&lt;0.05 vs RUPP). Fetal weight decreased from 2.4±0.04 g in Sham to 2.1±0.07 g in RUPP and 2.1±0.03 g in Sham+RUPP NK (p&lt;0.05 vs Sham), and this was normalized to 2.3±0.03 g in RUPP+Sham NK (p&lt;0.05 vs RUPP). UARI increased from 0.56±0.05 in Sham to 0.75±0.06 in RUPP and 0.76±0.05 in Sham+RUPP NK (p&lt;0.05 vs Sham), and decreased to 0.64±0.05 in RUPP+Sham NK (p&lt;0.05 vs RUPP). Circulating sFlt-1 increased from 76±15 pg/mL in Sham to 1391±424 pg/mL in RUPP (p&lt;0.05 vs Sham), 780±256 pg/mL in Sham+RUPP NK, and decreased to 67±8 pg/mL in RUPP+Sham NK (p&lt;0.05 vs RUPP). Furthermore, circulating VEGF decreased in RUPP and Sham+RUPP NK compared to Sham (p&lt;0.05), and increased in RUPP+Sham NK (p&lt;0.05 vs RUPP). These data demonstrate a direct role for cNKs to mediate vascular dysfunction in PE and for normal NKs to promote positive maternal and fetal outcomes.

Stage-Specific Requirement for Eomes in Mature NK Cell Homeostasis and Cytotoxicity

Natural killer (NK) cells are cytotoxic innate lymphoid cells (ILCs) that mediate antiviral and antitumor responses and require the transcriptional regulator Eomesodermin (Eomes) for early development. However, the role of Eomes and its molecular program in mature NK cell biology is unclear. To address this, we develop a tamoxifen-inducible, type-1-ILC-specific (Ncr1-targeted) cre mouse and combine this with Eomes-floxed mice. Eomes deletion after normal NK cell ontogeny results in a rapid loss of NK cells (but not ILC1s), with a particularly profound effect on penultimately mature stage III NK cells. Mechanisms responsible for stage III reduction include increased apoptosis and impaired maturation from stage II precursors. Induced Eomes deletion also decreases NK cell cytotoxicity and abrogates in vivo rejection of major histocompatibility complex (MHC)-class-I-deficient cells. However, other NK cell functional responses, and stage IV NK cells, are largely preserved. These data indicate that mature NK cells have distinct Eomes-dependent and -independent stages.