Tissue Determinants of Human NK Cell Development, Function, and Residence

Autocrine TGF-β1 drives tissue-specific differentiation and function of resident NK cells

Group 1 innate lymphoid cells (ILCs) encompass NK cells and ILC1s, which have non-redundant roles in host protection against pathogens and cancer. Despite their circulating nature, NK cells can establish residency in selected tissues during ontogeny, forming a distinct functional subset. The mechanisms that initiate, maintain, and regulate the conversion of NK cells into tissue-resident NK (trNK) cells are currently not well understood. Here, we identify autocrine transforming growth factor-β (TGF-β) as a cell-autonomous driver for NK cell tissue residency across multiple glandular tissues during development. Cell-intrinsic production of TGF-β was continuously required for the maintenance of trNK cells and synergized with Hobit to enhance cytotoxic function. Whereas autocrine TGF-β was redundant in tumors, our study revealed that NK cell-derived TGF-β allowed the expansion of cytotoxic trNK cells during local infection with murine cytomegalovirus (MCMV) and contributed to viral control in the salivary gland. Collectively, our findings reveal tissue-specific regulation of trNK cell differentiation and function by autocrine TGF-β1, which is relevant for antiviral immunity.

Advancing Natural Killer Cell Therapy: Genetic Engineering Strategies for Enhanced Cancer Immunotherapy

Natural killer (NK) cells are pivotal innate immune system components that exhibit spontaneous cytolytic activity against abnormal cells, such as infected and tumor cells. NK cells have shown significant promise in adoptive cell therapy because of their favorable safety profiles and minimal toxicity in clinical settings. Despite their advantages, the therapeutic application of unmodified NK cells faces challenges, including limited in vivo persistence, particularly in the immunosuppressive tumor microenvironment. Recent advances in genetic engineering have enhanced the therapeutic potential of NK cells by addressing these limitations and improving their therapeutic efficacy. In this review, we have described various methodologies for the genetic modification of NK cells, including viral vectors, electroporation, and nanoparticle-based approaches. The ongoing research on nanomaterialbased approaches highlights their potential to overcome current limitations in NK cell therapy, paving the way for advanced cancer therapy and improved clinical outcomes. In this review, we also emphasize the potential of engineered NK cells in cancer immunotherapy and other clinical applications, highlighting the expanding scope of NK cell-based treatments and the critical role of innovative genetic engineering techniques.

Distinct Tissue-Dependent Composition and Gene Expression of Human Fetal Innate Lymphoid Cells

The human fetal immune system starts to develop in the first trimester and likely plays a crucial role in fetal development and maternal-fetal tolerance. Innate lymphoid cells (ILCs) are the earliest lymphoid cells to arise in the human fetus. ILCs consist of natural killer (NK) cells, ILC1s, ILC2s, and ILC3s that all share a common lymphoid origin. Here, we studied fetal ILC subsets, mainly NK cells and ILC3s and their potential progenitors, across human fetal tissues. Our results show that fetal ILC subsets have distinct distribution, developmental kinetics, and gene expression profiles across human fetal tissues. Furthermore, we identify CD34+RORγt+Eomes- and CD34+RORγt+Eomes+ cells in the fetal intestine, indicating that tissue-specific ILC progenitors exist already during fetal development.

What's in a name? Memory NK cells for cancer immunotherapy

The discovery that natural killer (NK) cells can retain features of "memory" from previous stimulation and pathogen exposure was a landmark advance highlighting one of many ways in which NK cells of the innate immune system resemble T cells of the adaptive immune system. This ability to "remember" prior stimulation to bring about enhanced protection of the host sparked significant excitement regarding potential therapeutic applications. Yet, how closely the features of naïve and memory NK cells recapitulate those of T cells remains unclear. Nonetheless, despite unresolved questions about the immunobiology of naïve and memory NK cells, the application of memory NK cells to the clinic for cancer and other indications has gathered steam to meet the unmet need for novel immunotherapies. Recent work from Arellano-Ballestero et al highlights this evolving field and the current state of the art with memory NK cells. Application of these cells to the clinic is progressing with promising results, but important questions remain about the essential molecular, phenotypic, and functional characteristics that define a memory NK cell.

The role of CD101 and Tim3 in the immune microenvironment of gastric cancer and their potential as prognostic biomarkers

BACKGROUND

Gastric cancer (GC) is a prevalent malignancy. Current treatment modalities, including surgery, chemotherapy, radiotherapy, and targeted therapy, have limitations in early detection and personalized treatment, necessitating the discovery of novel biomarkers and therapeutic strategies. This study aims to elucidate the molecular mechanisms underlying GC, focusing on the differentially expressed genes (DEGs) of CD101- Tim3+ CD8+ T cells (CCT precursors) and CD101+ Tim3+ CD8+ T cells (CCT).

METHODS

Utilizing a multi-omics approach, including transcriptomic sequencing, single-cell RNA sequencing, cell communication analysis, and enrichment analysis.

RESULTS

We identified 140 genes significantly associated with overall survival in GC patients, including LYAR, ASCL2, and EMP2. A risk score model based on 14 prognostic genes was constructed, demonstrating a significant inverse correlation with survival time (p < 0.05). Immune response analysis indicated decreased infiltration of Activated B cells, CD56bright natural killer cells, and Monocytes in the high-risk group, while CD56dim natural killer cells and Gamma delta T cells were significantly increased, suggesting alterations in the immune microenvironment that influence patient prognosis. Furthermore, drug sensitivity analysis revealed potential responsiveness of high-risk patients to BI-2536, supporting personalized treatment approaches. Cell communication analysis indicated reduced intercellular interactions in PD-1 immunotherapy groups, highlighting the impact of immunotherapy on the tumor microenvironment. GSEA (Gene Set Enrichment Analysis) and GSVA (Gene Set Variation Analysis) revealed enrichment in DNA replication and proteasome pathways in high-risk groups, providing insights into the molecular mechanisms of GC.

CONCLUSIONS

This study established a foundation for future exploration of targeted therapies and personalized treatment strategies in GC.

The diversity of natural killer cell functional and phenotypic states in cancer

The role of natural killer (NK) cells as immune effectors is well established, as is their utility as immunotherapeutic agents against various cancers. However, NK cells' anti-cancer roles are suppressed in cancer patients by various immunomodulatory mechanisms which alter these cells' identity, function, and potential for immunosurveillance. This manifests in abnormal NK cell responses accompanied by changes in phenotypic or genotypic identity, giving rise to specific NK cell subsets that are either hypofunctional or, more broadly, defective in their responses. Anergy, senescence, and exhaustion are some of the terms that have been used to define and characterize these NK cell functional states. These responses vary not only with cancer type but also NK cell location within tissues. Collectively, these phenomena suggest a highly plastic nature of NK cell biology in tumors. In this review, we present and discuss a summary of these functionally distinct states and provide an overview of how NK cells behave at different locations within the context of cancer.

Research Progress of NK Cells in Glioblastoma Treatment

NK cells are a type of antitumor immune cell with promising clinical application, following T cells. The activity of NK cells is primarily regulated by their surface receptors and immune microenvironment. In gliomas, the tumor microenvironment exerts a strong immunosuppressive effect, which significantly reduces the clinical efficacy of NK cell immunotherapy. Therefore, this review aims to discuss the latest research on the role of NK cells in glioma immunotherapy, focusing on aspects such as NK cell development, function, and localization. It summarizes information on the compounds, monoclonal antibodies, and cytokine therapies targeting NK cells while emphasizing the current status and trends of gene-modified NK cells in glioma treatment. Additionally, it explores the molecular mechanisms underlying immune escape in glioma cells, providing a theoretical foundation and new perspectives for NK cell-based immunotherapy in gliomas.

Tissue-resident immune cells: from defining characteristics to roles in diseases

Tissue-resident immune cells (TRICs) are a highly heterogeneous and plastic subpopulation of immune cells that reside in lymphoid or peripheral tissues without recirculation. These cells are endowed with notably distinct capabilities, setting them apart from their circulating leukocyte counterparts. Many studies demonstrate their complex roles in both health and disease, involving the regulation of homeostasis, protection, and destruction. The advancement of tissue-resolution technologies, such as single-cell sequencing and spatiotemporal omics, provides deeper insights into the cell morphology, characteristic markers, and dynamic transcriptional profiles of TRICs. Currently, the reported TRIC population includes tissue-resident T cells, tissue-resident memory B (BRM) cells, tissue-resident innate lymphocytes, tissue-resident macrophages, tissue-resident neutrophils (TRNs), and tissue-resident mast cells, but unignorably the existence of TRNs is controversial. Previous studies focus on one of them in specific tissues or diseases, however, the origins, developmental trajectories, and intercellular cross-talks of every TRIC type are not fully summarized. In addition, a systemic overview of TRICs in disease progression and the development of parallel therapeutic strategies is lacking. Here, we describe the development and function characteristics of all TRIC types and their major roles in health and diseases. We shed light on how to harness TRICs to offer new therapeutic targets and present burning questions in this field.

Single cell profiling of hematopoietic stem cell transplant recipients reveals TGF-β1 and IL-2 confer immunoregulatory functions to NK cells

Natural killer (NK) cell activity is influenced by cytokines and microenvironment factors, resulting in remarkably diverse functions, by contributing to inflammatory responses or serving as rheostats of adaptive immunity. Using single cell RNA sequencing (scRNA-seq), we identified a TGFβ1 highCD56brightNK cell population associated with hematopoietic stem cell transplant recipients protected from acute graft-versus-host disease (GVHD). We further define a role for the combination of interleukin-2 (IL-2) and transforming growth factor β1 (TGF-β1) in promoting a regulatory phenotype in NK cells. "Induced" regulatory NK cells produce high amounts of TGF-β1, inhibited T cells, could promote naive T cells differentiation into regulatory T cells, and exhibited a unique transcriptional program that includes expression of IKZF2 (HELIOS) and ZNF683 (HOBIT). This phenotype was not stable, and "induced" regulatory NK cells lost the ability to secrete TGF-β1 upon exposure to different cytokines. These findings define protective CD56brightNK cells post-hematopoietic stem cell transplantation, and demonstrate the combination of IL-2 and TGF-β1 promotes regulatory activity in NK cells.

CAR T cells in autoimmune disease: On the road to remission

Several recent reports have demonstrated that B cell-targeting chimeric antigen receptor (CAR) T cells offer a viable treatment option for patients with autoantibody-mediated autoimmune diseases. To present additional data on this therapy and discuss strategies for more efficient clinical translation, leading experts in CAR T cell therapy for autoimmunity from various countries, including China, Germany, and the United States, convened at the "1st International Autoimmune CAR T Innovators Summit" in Grassau, Germany, from May 10-12, 2024. The summit showcased additional insights of CAR T cell therapy in diverse autoimmune diseases and provided platforms for discussions on key questions through workshops and roundtables. Here, we summarize the recent findings and key developments reported at the summit.

Maintenance and functional regulation of immune memory to COVID-19 vaccines in tissues

Memory T and B cells in tissues are essential for protective immunity. Here, we performed a comprehensive analysis of the tissue distribution, phenotype, durability, and transcriptional profile of COVID-19 mRNA vaccine-induced immune memory across blood, lymphoid organs, and lungs obtained from 63 vaccinated organ donors aged 23-86, some of whom experienced SARS-CoV-2 infection. Spike (S)-reactive memory T cells were detected in lymphoid organs and lungs and variably expressed tissue-resident markers based on infection history, and S-reactive B cells comprised class-switched memory cells resident in lymphoid organs. Compared with blood, S-reactive tissue memory T cells persisted for longer times post-vaccination and were more prevalent with age. S-reactive T cells displayed site-specific subset compositions and functions: regulatory cell profiles were enriched in tissues, while effector and cytolytic profiles were more abundant in circulation. Our findings reveal functional compartmentalization of vaccine-induced T cell memory where surveilling effectors and in situ regulatory responses confer protection with minimal tissue damage.

The development and application of chimeric antigen receptor natural killer (CAR-NK) cells for cancer therapy: current state, challenges and emerging therapeutic advances

Immunotherapy has transformed the landscape of cancer treatment, with chimeric antigen receptor (CAR)-engineered T (CAR-T) cell therapy emerging as a front runner in addressing some hematological malignancies. Despite its considerable efficacy, the occurrence of severe adverse effects associated with CAR-T cell therapy has limited their scope and prompted the exploration of alternative therapeutic strategies. Natural killer (NK) cells, characterized by both their innate cytotoxicity and ability to lyse target cells without the constraint of peptide specificity conferred by a major histocompatibility complex (MHC), have similarly garnered attention as a viable immunotherapy. As such, another therapeutic approach has recently emerged that seeks to combine the continued success of CAR-T cell therapy with the flexibility of NK cells. Clinical trials involving CAR-engineered NK (CAR-NK) cell therapy have exhibited promising efficacy with fewer deleterious side effects. This review aims to provide a concise overview of the cellular and molecular basis of NK cell biology, facilitating a better understanding of advancements in CAR design and manufacturing. The focus is on current approaches and strategies employed in CAR-NK cell development, exploring at both preclinical and clinical settings. We will reflect upon the achievements, advantages, and challenges intrinsic to CAR-NK cell therapy. Anticipating the maturation of CAR-NK cell therapy technology, we foresee its encouraging prospects for a broader range of cancer patients and other conditions. It is our belief that this CAR-NK progress will bring us closer to making significant strides in the treatment of refractory and recurrent cancers, as well as other immune-mediated disorders.

Lung-resident lymphocytes and their roles in respiratory infections and chronic respiratory diseases

Recent scientific breakthroughs have blurred traditional boundaries between innate and adaptive immunity, revealing a sophisticated network of tissue-resident cells that deliver immediate, localized immune responses. These lymphocytes not only provide rapid frontline defense but also present a paradoxical role in the pathogenesis of respiratory diseases such as asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and the long-term tissue consequences of viral infections including severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This review traverses the intricate landscape of lung-resident lymphocytes, delving into their origins, diverse functions, and their dualistic impact on pulmonary health. We dissect their interactions with the microenvironment and the regulatory mechanisms guiding their activity, with an emphasis on their contribution to both immune protection and immunopathology. This review aims to elucidate the complex narrative of these cells, enhancing our understanding of the development of precise therapeutic strategies to combat acute and chronic pulmonary diseases. Through this exploration, the review aspires to shed light on the potential of harnessing lung-resident lymphocytes for the treatment of respiratory conditions.

Genetic mutations and immune microenvironment: unveiling the connection to AML prognosis

BACKGROUND

This study aims to investigate the correlation between NK and NKT cell proportion disparities and prognosis in patients with acute myeloid leukemia (AML).

METHODS

Forty-four cases of acute myeloid leukemia patients were selected, and flow cytometry was utilized to evaluate the expression of bone marrow NK and NKT cells. Next-generation sequencing technology was employed to detect genetic mutations in these 44 AML patients, and the rates of first induction remission and overall survival were recorded. Comparisons were made to analyze the respective differences in NK and NKT cell proportions among AML patients with various genetic mutations and risk stratifications.

RESULTS

The FLT-3-ITD+ group exhibited a significant increase in the proportion of NK cells compared to the normal control group and FLT3-ITD+/NPM1+ group, whereas the proportion of NKT cells was significantly decreased. Additionally, the CEBPA+ group showed an increased proportion of NKT cells compared to the TP53+ group and ASXL1+ group. The high-risk group had a higher proportion of NK cells than the intermediate-risk group, while the proportion of NKT cells was lower in the high-risk group compared to the intermediate-risk group.Patients achieving first induction remission displayed a higher proportion of NKT cells at initial diagnosis compared to those who did not achieve remission. The distribution of NK cells show significant differences among AML patients in different survival periods.

CONCLUSION

This results implies that distinct genetic mutations may play a role not only in tumor initiation but also in shaping the tumor microenvironment, consequently impacting prognosis.

Analysis of the presence of natural killer cell subpopulations in preterm human milk: A first approach

Several immune cell populations are transferred to the newborn through breast milk, including natural killer (NK) cells, which are critical for innate defense and regulation of the immune response, especially in preterm infants. The aim of this study was to analyze the presence of NK cell subpopulations in different types of preterm breast milk. The study quantified the presence of NK cell subpopulations by flow cytometry using the relative expression of CD56 and CD16 markers in colostrum, transitional and mature milk samples from preterm mothers. Flow cytometry analysis revealed the presence of five NK cell subpopulations, but unlike those reported in peripheral blood, CD56dimCD16+ and CD56-CD16+ populations are predominantly present in preterm milk, only the CD56brightCD16dim population is increased in mature milk. Analysis of NK cell subpopulations in preterm milk revealed a pattern of NK cell presence in preterm breast milk with predominantly cytotoxic phenotypes in relation to CD16 marker expression.

Impact of chronic stress on intestinal mucosal immunity in colorectal cancer progression

Chronic stress is a significant risk factor that contributes to the progression of colorectal cancer (CRC) and has garnered considerable attention in recent research. It influences the distribution and function of immune cells within the intestinal mucosa through the "brain-gut" axis, altering cytokine and chemokine secretion and creating an immunosuppressive tumor microenvironment. The intestine, often called the "second brain," is particularly susceptible to the effects of chronic stress. Cytokines and chemokines in intestinal mucosal immunity（IMI） are closely linked to CRC cells' proliferation, metastasis, and drug resistance under chronic stress. Recently, antidepressants have emerged as potential therapeutic agents for CRC, possibly by modulating IMI to restore homeostasis and exert anti-tumor effects. This article reviews the role of chronic stress in promoting CRC progression via its impact on intestinal mucosal immunity, explores potential targets within the intestinal mucosa under chronic stress, and proposes new approaches for CRC treatment.

CD2 expressing innate lymphoid and T cells are critical effectors of immunopathogenesis in hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic, debilitating inflammatory skin disease with a poorly understood immunopathogenesis. Here, we report that HS lesional skin is characterized by the expansion of innate lymphocytes and T cells expressing CD2, an essential activation receptor and adhesion molecule. Lymphocytes expressing elevated CD2 predominated with unique spatial distribution throughout the epidermis and hypodermis in the HS lesion. CD2+ cells were mainly innate lymphocytes expressing the NK cell marker, CD56, and CD4+ T cells. Importantly, these CD2+ cells interacted with CD58 (LFA3) expressing epidermal keratinocytes and fibroblasts in the hypodermis. Granzyme Abright NKT cells (CD2+CD3+CD56bright) clustered with α-SMA expressing fibroblasts juxtaposed to epithelialized tunnels and fibrotic regions of the hypodermis. Whereas NK cells (CD2+CD56dim) were perforin+, granzymes A+ and B+, and enriched adjacent to hyperplastic follicular epidermis and tunnels of HS showing presence of apoptotic cells. The cytokines IL-12, IL-15, and IL-18, which enhance NK cell maturation and function were significantly elevated in HS. Ex vivo HS skin explant cultures treated with CD2:CD58 interaction-blocking anti-CD2 monoclonal antibody attenuated secretion of inflammatory cytokines/chemokines and suppressed inflammatory gene signature. Additionally, CD2:CD58 blockade altered miRNAs involved in NK/NKT differentiation and/or function. In summary, we show that a cellular network of heterogenous NKT and NK cell populations drives inflammation and is critical in the pathobiology of HS, including tunnel formation and fibrosis. Finally, CD2 blockade is a viable immunotherapeutic approach for the effective management of HS.

Relation of CMV and brain atrophy to trajectories of immunosenescence in diverse populations

Immunosenescence (ISC), the aging of the immune system, has largely been studied in populations of European descent. Here, circulating immune cell cytometric data from African-American, Hispanic, and non-Hispanic White participants were generated. Known and novel age effects were identified using either a meta-analysis approach or a parallel genetic approach. Most results are consistent across the three populations, but some cell populations display evidence of heterogeneity, such as a PD-L1 + CD56 + NK cell subset. The study estimated "Immunological Age" (IA) during physiologic aging. While we found no relation of IA to Multiple Sclerosis, IA is associated with entorhinal cortex atrophy, a presymptomatic feature of Alzheimer's disease, linking neurodegeneration and peripheral immunity. ISC trajectories were also inferred, highlighting age, CMV status, and genetic ancestry as key influences. Our assessment offers reference ISC trajectories for personalization of assessments of immune function over the life course in diverse populations.

The role and molecular mechanism of Trametes Robiniophila Murr(Huaier) in tumor therapy

ETHNOPHARMACOLOGICAL RELEVANCE

Trametes Robiniophila Murr, commonly known as Huaier, has been extensively documented in ethnopharmacology research in China. Huaier has a long history of clinical usage spanning over 1000 years in China. Traditional clinical application records demonstrate the wide utilization of Huaier for treating various cancers and enhancing the autoimmunity of tumor patients.

AIM OF THE REVIEW

The present study provides a comprehensive review of the traditional uses, phytochemical constituents, pharmacological activities, anti-tumor mechanism, and potential applications of Huaier, thereby offering valuable insights for the further development and utilization of this natural product.

MATERIALS AND METHODS

This study employed the keywords "Trametes Robiniophila Murr" and "Huaier" to retrieve relevant information on Huaier from various databases, including PubMed, Web of Science, Springer, Science Direct, ACS, Wiley, CNKI, Baidu Scholar, Google Scholar, and ancient materia medica.

RESULTS

Trametes Robiniophila Murr (Huaier), a traditional Chinese medicine, has demonstrated significant efficacy in the clinical treatment of various tumors. The primary bioactive constituents of Huaier consist of fungal-derived compounds, including polysaccharides, proteins, ketones, alkaloids, and minerals. The research findings demonstrate that Huaier serves as a reliable adjunctive therapeutic agent by effectively inhibiting cancer cell proliferation, inducing apoptosis in cancer cells, suppressing tumor metastasis, regulating tumor stem cells and immune function. Therefore, it exerts a potent anti-tumor effect when used in conjunction with conventional anti-cancer therapies.

CONCLUSIONS

The analysis of traditional uses, phytochemical composition, and pharmacological activity reveals that Huaier exhibits significant potential as a medicinal plant with diverse pharmacological effects. Owing to its numerous advantages, Huaier holds immense promise for application in the domains of tumor prevention and treatment, enhancing both survival time and quality of life among cancer patients.

Innate Immunity and Synovitis: Key Players in Osteoarthritis Progression

Osteoarthritis (OA) is a chronic progressive disease of the joint. Although representing the most frequent cause of disability in the elderly, OA remains partly obscure in its pathogenic mechanisms and is still the orphan of resolutive therapies. The concept of what was once considered a "wear and tear" of articular cartilage is now that of an inflammation-related disease that affects over time the whole joint. The attention is increasingly focused on the synovium. Even from the earliest clinical stages, synovial inflammation (or synovitis) is a crucial factor involved in OA progression and a major player in pain onset. The release of inflammatory molecules in the synovium mediates disease progression and worsening of clinical features. The activation of synovial tissue-resident cells recalls innate immunity cells from the bloodstream, creating a proinflammatory milieu that fuels and maintains a damaging condition of low-grade inflammation in the joint. In such a context, cellular and molecular inflammatory behaviors in the synovium could be the primum movens of the structural and functional alterations of the whole joint. This paper focuses on and discusses the involvement of innate immunity cells in synovitis and their role in the progression of OA.

Germline natural killer cell receptors modulating the T cell response

In addition to their central role during innate responses, NK cells regulate adaptive immunity through various mechanisms. A wide array of innate receptors has been involved in the NK cell regulatory function. However, the clinical implications of these regulatory pathways are poorly understood. Here, we review the experimental evidence on the effects of NK cells on T cells and their positive and negative consequences for disease outcome during T cell responses in humans.

Inhibition of NFAT promotes loss of tissue resident uterine natural killer cells and attendant pregnancy complications in humans

Uterine natural killer cells (uNKs) are a tissue resident lymphocyte population that are critical for pregnancy success. Although mouse models have demonstrated that NK deficiency results in abnormal placentation and poor pregnancy outcomes, the generalizability of this knowledge to humans remains unclear. Here we identify uterus transplant (UTx) recipients as a human population with reduced uNK cells and altered pregnancy phenotypes. We show that the NK reduction in UTx correlates with impaired transcriptional programming of NK tissue residency arising from the inhibition of NFAT-mediated signaling. Our observations suggest that NFAT-dependent genes modulate multiple molecular tissue residency programs in uNKs. These include early residency programs involving AP-1-family transcription factors and TGF-β-mediated upregulation of surface integrins. Collectively, our data identify a previously undescribed role for NFAT in uterine NK tissue residency and provide novel mechanistic insights into the biologic basis of pregnancy complications due to alteration of tissue resident NK subsets in humans.

One Sentence Summary

Role of NFAT in uterine NK cell tissue residency.

Causal associations of MICB, CTSA, and MMP9 proteins with oral cancer: Mendelian randomization study

Oral cancer (ORCA) is the most prevalent histological subtype of oral malignancies in which immune modulation is relevant. The goal of this work was to employ Mendelian randomization (MR) to investigate the causal connection between the immune-related proteins MICB, CTSA, MMP9, and ORCA. The Open GWAS database of the Integrative Epidemiology Unit (IEU) was accessed to collect GWAS data for ORCA (ieu-b-4961), MICB (prot-a-1898), CTSA (prot-a-717) and MMP9 (prot-a-1921). From 372,373 samples, the ORCA dataset comprises 7,723,107 single nucleotide polymorphisms (SNPs). MICB, CTSA, and MMP9 all have 10,534,735 SNPs and 3,301 sample sizes. Then, the primary SVMR implementation approaches were weighted mode, simple mode, inverse variance weighted (IVW), weighted median, and MR-Egger. IVW was the most effective technique. A sensitivity study was also carried out to assess the correctness of SVMR data, with special focus devoted to heterogeneity, horizontal pleiotropy, and Leave-One-Out (LOO). MVMR was eventually implemented as well. A Mendelian randomization analysis of the three exposure factors in the dataset (ieu-b-94, ebi-a-GCST012237) was also performed to validate the study results. According to the SVMR results, there was a noteworthy causal interaction between ORCA and MICB (P = 0.0014), MMP9 (P = 0.0343), and CTSA (P = 0.0003). Furthermore, odds ratios (ORs) values revealed that MMP9 (OR = 1.0005) was an ORCA risk factor, whereas MICB (OR = 0.9994) and CTSA (OR = 0.9993) were security factors. The robustness of the SVMR findings was confirmed by the p-values of the heterogeneity and horizontal pleiotropy, both of which were greater than 0.05. The MVMR result did not affect any of the safety or hazard features of these three exposure factors. However, the P value for MMP9 was greater than 0.05, implying that MICB and CTSA may have a greater influence on ORCA than MMP9. The validation outcomes in both datasets harmonized with the findings from previous research, thereby solidifying the reliability of results. Our investigation provided a crucial resource for further research on the subject by demonstrating a causal relationship between ORCA and MICB, CTSA, and MMP9.

Modeling NK-cell lymphoma in mice reveals its cell-of-origin and microenvironmental changes and identifies therapeutic targets

Extranodal NK/T-cell lymphoma (ENKTCL) is an Epstein-Barr virus (EBV)-related neoplasm preferentially involving the upper aerodigestive tract. Here we show that NK-cell-specific Trp53 disruption in mice leads to the development of NK-cell lymphomas after long latency, which involve not only the hematopoietic system but also the salivary glands. Before tumor onset, Trp53 knockout causes extensive gene expression changes, resulting in immature NK-cell expansion, exclusively in the salivary glands. Both human and murine NK-cell lymphomas express tissue-resident markers, suggesting tissue-resident NK cells as their cell-of-origin. Murine NK-cell lymphomas show recurrent Myc amplifications and upregulation of MYC target gene signatures. EBV-encoded latent membrane protein 1 expression accelerates NK-cell lymphomagenesis and causes diverse microenvironmental changes, particularly myeloid propagation, through interferon-γ signaling. In turn, myeloid cells support tumor cells via CXCL16-CXCR6 signaling and its inhibition is effective against NK-cell tumors in vivo. Remarkably, KLRG1-expressing cells expand in the tumor and are capable of repopulating tumors in secondary recipients. Furthermore, targeting KLRG1 alone or combined with MYC inhibition using an eIF4 inhibitor is effective against NK-cell tumors. Therefore, our observations provide insights into the pathogenesis and highlight potential therapeutic targets, including CXCL16, KLRG1, and MYC, in ENKTCL, which can help improve its diagnostic and therapeutic strategies.

Natural killer cell-based cancer immunotherapy: from basics to clinical trials

Cellular immunotherapy exploits the capacity of the human immune system in self-protection and surveillance to achieve the anti-tumor effects. Natural killer (NK) cells are lymphocytes of innate immune system and they display a unique inherent ability to identify and eliminate tumor cells. In this review, we first introduce the basic characteristics of NK cells in the physiological and pathological milieus, followed by a discussion of their effector function and immunosuppression in the tumor microenvironment. Clinical strategies and reports regarding NK cellular therapy are analyzed in the context of tumor treatment, especially against solid tumors. Given the widely studied T-cell therapy in the recent years, particularly the chimeric antigen receptor (CAR) T-cell therapy, we compare the technical features of NK- and T-cell based tumor therapies at the clinical front. Finally, the technical challenges and potential solutions for both T and NK cell-based immunotherapies in treating tumor malignancies are delineated. By overviewing its clinical applications, we envision the NK-cell based immunotherapy as an up-and-comer in cancer therapeutics.

The activating receptor NKG2D is an anti-fungal pattern recognition receptor

NKG2D is a central activating receptor involved in target recognition and killing by Natural Killer and CD8+ T cells. The known role of NKG2D is to recognize a family of self-induced stress ligands that are upregulated on stressed cells such as cancerous or virally infected cells. Fungal pathogens are a major threat to human health, infecting more than a billion patients yearly and becoming more common and drug resistant. Here we show that NKG2D plays a critical role in the immune response against fungal infections. NKG2D can recognize fungal pathogens from most major families including Candida, Cryptococcus and Aspergillus species, and mice lacking NKG2D are extremely sensitive to fungal infections in models of both invasive and mucosal infections, making NKG2D an anti-fungal pattern recognition receptor.

Lower peripheral blood CD4+ lymphocyte ratio is associated with severe bronchopulmonary dysplasia

OBJECTIVE

To elucidate the characteristics of lymphocyte subsets in bronchopulmonary dysplasia (BPD) diagnosis following Jensen's criterion to understand the spectrum of lymphocytes in different degrees of BPD.

STUDY DESIGN

This single-center retrospective cohort study included 120 neonates admitted to the neonatal intensive care unit between 1 July 2014 and 30 June 2021, who had undergone peripheral blood lymphocyte subpopulation detection.

RESULTS

Thirty-one neonates were included in the control group, whereas 33 infants with BPD were included in the case group. In addition, we selected 56 infants with a gestational age (GA) <37 weeks without BPD who were receiving oxygen therapy. Among the three groups, the B cell and NK cell frequencies were significantly higher and the frequencies of T cells and CD4+ cells were significantly lower in the BPD group. In newborns without BPD, the distribution of T lymphocyte subsets was similar at different GAs. Comparing different degrees of BPD, the patients in the grades 2-3 BPD group had significantly lower percentages of T lymphocytes and CD4+ T cells than those in the other groups. Remarkably, the frequencies of NK cells were significantly higher in patients with grades 2-3 BPD, and the Treg cells slightly increased with BPD severity, although the differences were not significant.

CONCLUSION

Healthy neonates had similar ratios of lymphocyte subsets among different GAs; although as the GAs increased, the percentage of lymphocytes increased slightly. Severe BPD was associated with lower CD4+ T cells and higher NK cells. However, whether such changes were the cause or the consequence of BPD has not been determined.

Natural killer cell-associated prognosis model characterizes immune landscape and treatment efficacy of diffuse large B cell lymphoma

PURPOSE

NK cells are essential for the detection, identification and prediction of cancer. However, so far, there is no prognostic risk model based on NK cell-related genes to predict the prognosis and treatment outcome of DLBCL patients. This study aimed to explore a risk assessment model that could accurately predict the prognosis and treatment efficacy of DLBCL.

METHODS

Bioinformatics analysis of the expression profiles of DLBCL samples in the GEO database was performed. Cox regression and LASSO regression analysis were used to determine NK cell-related genes associated with patient's prognosis. Based on these genes, a risk assessment model was constructed to predict the prognosis of patients and the effectiveness of treatment. Finally, qRT-PCR was used to verify the expression of gene tags in clinical samples.

RESULTS

We identified seven prognosis-related NK cell-related genes (MAP2K1, PRKCB, TNFRSF10B, IL18, LAMP1, RASGRP1, and SP110), and DLBCL patients were divided into low- and high-risk groups based on these genes. Survival analysis showed that the prognosis of patients with low-risk group was better. Pathway enrichment analysis showed that the differentially expressed genes between the two risk groups were related to immune response pathways. Compared with the high-risk group, the low-risk group had higher infiltration of immune cells in tumor tissues. Besides, compared with high-risk group, low-risk patients by immunotherapy or other commonly used anti-tumor drugs might have better efficacy after treatment. In addition, qRT-PCR showed that the expression of risk genes including TNFRSF10B, IL18 and LAMP1 were significantly increased in most DLBCL samples compared to control samples, while the expression of protective genes including MAP2K1, PRKCB, RASGRP1 and SP110 were significantly decreased.

CONCLUSION

The NK cell-related gene signatures were proved to be a reliable indicator of the success of immunotherapy in patients with DLBCL, thus providing a unique evaluation method.

From the midfacial destructive drama to the unfolding EBV story: a short history of EBV-positive NK-cell and T-cell lymphoproliferative diseases

Epstein-Barr virus (EBV) is a ubiquitous gammaherpesvirus that has been related to oncogenesis of lymphoid and epithelial malignancies. Although the mechanism of EBV infection of NK and T cells remains enigmatic, it plays a pathogenic role in various EBV+ NK-cell and T-cell lymphoproliferative diseases (LPDs), through promotion of cell activation pathways, inhibition of cell apoptotic pathways, behaving as oncogenes, interacting with host oncogenes or acting epigenetically. The study of NK-cell LPDs, previously hampered by the lack of immunophenotypical and genotypical criteria of NK cells, has become feasible with the recently accepted criteria. EBV+ NK- and T-cell LPDs are mostly of poor prognosis. This review delivers a short history from primeval to recent EBV+ NK- and T-cell LPDs in non-immunocompromised subjects, coupled with increasing interest, and work on the biological and oncogenic roles of EBV.

Development in the Study of Natural Killer Cells for Malignant Peritoneal Mesothelioma Treatment

Malignant peritoneal mesothelioma (MPeM) is a rare primary malignant tumor originating from peritoneal mesothelial cells. Insufficient specificity of the symptoms and their frequent reappearance following surgery make it challenging to diagnose, creating a need for more efficient treatment options. Natural killer cells (NK cells) are part of the innate immune system and are classified as lymphoid cells. Under the regulation of activating and inhibiting receptors, NK cells secrete various cytokines to exert cytotoxic effects and participate in antiforeign body, antiviral, and antitumor activities. This review provides a comprehensive summary of the specific alterations observed in NK cells following MPeM treatment, including changes in cell number, subpopulation distribution, active receptors, and cytotoxicity. In addition, we summarize the impact of various therapeutic interventions, such as chemotherapy, immunotherapy, and targeted therapy, on NK cell function post-MPeM treatment.

Pancreatic ductal adenocarcinoma microenvironment: Soluble factors and cancer associated fibroblasts as modulators of NK cell functions

Pancreatic Ductal Adenocarcinoma (PDAC) is the most frequent pancreatic cancer and represents one of the most aggressive human neoplasms. Typically identified at advance stage disease, most PDAC tumors are unresectable and resistant to standard therapies. The immunosuppressive microenvironment in PDAC impedes tumor control but a greater understanding of the complex stromal interactions within the tumor microenvironment (TME) and the development of strategies capable of restoring antitumor effector immune responses could be crucial to fight this aggressive tumor and its spread. Natural Killer (NK) cells play a crucial role in cancer immunosurveillance and represent an attractive target for immunotherapies, both as cell therapy and as a pharmaceutical target. This review describes some crucial components of the PDAC TME (collagens, soluble factors and fibroblasts) that can influence the presence, phenotype and function of NK cells in PDAC patients tumor tissue. This focused overview highlights the therapeutic relevance of dissecting the complex stromal composition to define new strategies for NK cell-based immunotherapies to improve the treatment of PDAC.

Natural Killer Cell Dysfunction In Human Bladder Cancer Is Caused By Tissue-Specific Suppression of SLAMF6 Signaling

NK cells are innate lymphocytes critical for surveillance of viruses and tumors, however the mechanisms underlying NK cell dysfunction in cancer are incompletely understood. We assessed the effector function of NK cells from bladder cancer patients and found severe dysfunction in NK cells derived from tumors versus peripheral blood. While both peripheral and tumor-infiltrating NK cells exhibited conserved patterns of inhibitory receptor over-expression, this did not explain the observed defects in NK surveillance in bladder tumors. Rather, TME-specific TGF-β and metabolic perturbations such as hypoxia directly suppressed NK cell function. Specifically, an oxygen-dependent reduction in signaling through SLAMF6 was mechanistically responsible for poor NK cell function, as tumor-infiltrating NK cells cultured ex vivo under normoxic conditions exhibited complete restoration of function, while deletion of SLAMF6 abrogated NK cell cytolytic function even under normoxic conditions. Collectively, this work highlights the role of tissue-specific factors in dictating NK cell function, and implicates SLAMF6 signaling as a rational target for immuno-modulation to improve NK cell function in bladder cancer.

Genetically defined causal effects of natural killer cells related traits in risk of infection: a Mendelian randomization study

BACKGROUND

The intricate interplay between genetics and immunology often dictates the host's susceptibility to various diseases. This study explored the genetic causal relationship between natural killer (NK) cell-related traits and the risk of infection.

METHODS

Single-nucleotide polymorphisms (SNPs) significantly associated with NK cell-related traits were selected as instrumental variables to estimate their genetic causal effects on infection. SNPs from a genome-wide association study (GWAS) on NK cell-related traits, including absolute cell counts, median fluorescence intensities reflecting surface antigen levels, and relative cell counts, were used as exposure instruments. Summary-level GWAS statistics of four phenotypes of infection were used as the outcome data. The exposure and outcome data were analyzed via the two-sample Mendelian randomization method.

RESULTS

Each one standard deviation increase in the expression level of human leukocyte antigen (HLA)-DR on HLA-DR+ NK cells was associated with a lower risk of pneumonia (P < 0.05). An increased HLA-DR+ NK/CD3- lymphocyte ratio was related to a lower of risk of pneumonia (P  < 0.05). Each one standard deviation increase in the absolute count of HLA-DR+ NK cells was associated with a lower risk of both bacterial pneumonia and pneumonia (P < 0.05). An increased HLA-DR+ NK/NK ratio was associated with a decreased risk of both pneumonia and bacterial pneumonia (P < 0.05). The results were robust under all sensitivity analyses. No evidence for heterogeneity, pleiotropy, or potential reverse causality was detected. Notably, our analysis did not reveal any significant associations between NK cell-related traits and other phenotypes of infection, including cellulitis, cystitis, and intestinal infection.

CONCLUSIONS

HLA-DR+ NK cells could be a novel immune cell trait associated with a lower risk of bacterial pneumonia or pneumonia.

High ratio of resident to exhausted CD4 + T cells predicts favorable prognosis and potentially better immunotherapeutic efficacy in hepatocellular carcinoma

BACKGROUND

Tumor-infiltrating lymphocytes (TILs) are significantly implicated in regulating the tumor immune microenvironment (TIME) and immunotherapeutic response. However, little is known about the impact of the resident and exhausted status of TILs in hepatocellular carcinoma (HCC).

METHODS

Single-cell RNA sequencing data was applied to discover resident and exhausted signatures of TILs. Survival outcomes, biological function, immune infiltration, genomic variation, immunotherapeutic efficacy, and sorafenib response were further explored the clinical significance and molecular association of TILs in HCC. Moreover, a candidate gene with predictive capability for the dismal subtype was identified through univariate Cox regression analysis, survival analysis, and the BEST website.

RESULTS

Single-cell analysis revealed that CD8 + T, CD4 + T, and NK cells were strongly associated with resident and exhausted patterns. Specific resident and exhausted signatures for each subpopulation were extracted in HCC. Further multivariate Cox analysis revealed that the ratio of resident to exhausted CD4 + T cells in TIME was an independent prognostic factor. After incorporating tumor purity with the ratio of resident to exhausted CD4 + T cells, we stratified HCC patients into three subtypes and found that (i) CD4 residencyhighexhaustionlow subtype was endowed with favorable prognosis, immune activation, and sensitivity to immunotherapy; (ii) CD4 exhaustionhighresidencylow subtype was characterized by genome instability and sensitivity to sorafenib; (iii) Immune-desert subtype was associated with malignant-related pathways and poor prognosis. Furthermore, spindle assembly abnormal protein 6 homolog (SASS6) was identified as a key gene, which accurately predicted the immune-desert subtype. Prognostic analysis as well as in vitro and in vivo experiments further demonstrated that SASS6 was closely associated with tumor prognosis, proliferation, and migration.

CONCLUSIONS

The ratio of resident to exhausted CD4 + T cells shows promise as a potential biomarker for HCC prognosis and immunotherapy response and SASS6 may serve as a biomarker and therapeutic target for prognostic assessment of HCC.

Longitudinal Multi-omic Immune Profiling Reveals Age-Related Immune Cell Dynamics in Healthy Adults

The generation and maintenance of protective immunity is a dynamic interplay between host and environment that is impacted by age. Understanding fundamental changes in the healthy immune system that occur over a lifespan is critical in developing interventions for age-related susceptibility to infections and diseases. Here, we use multi-omic profiling (scRNA-seq, proteomics, flow cytometry) to examined human peripheral immunity in over 300 healthy adults, with 96 young and older adults followed over two years with yearly vaccination. The resulting resource includes scRNA-seq datasets of >16 million PBMCs, interrogating 71 immune cell subsets from our new Immune Health Atlas. This study allows unique insights into the composition and transcriptional state of immune cells at homeostasis, with vaccine perturbation, and across age. We find that T cells specifically accumulate age-related transcriptional changes more than other immune cells, independent from inflammation and chronic perturbation. Moreover, impaired memory B cell responses to vaccination are linked to a Th2-like state shift in older adults' memory CD4 T cells, revealing possible mechanisms of immune dysregulation during healthy human aging. This extensive resource is provided with a suite of exploration tools at https://apps.allenimmunology.org/aifi/insights/dynamics-imm-health-age/ to enhance data accessibility and further the understanding of immune health across age.

Construction and validation of a TAMRGs prognostic signature for gliomas by integrated analysis of scRNA and bulk RNA sequencing data

BACKGROUND

This study aimed to construct and validate a prognostic model based on tumor associated macrophage-related genes (TAMRGs) by integrating single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing (bulk RNA-seq) data.

METHODS

The scRNA-seq data of three inhouse glioma tissues were used to identify the tumor-associated macrophages (TAMs) marker genes, the DEGs from the The Cancer Genome Atlas (TCGA) - Genotype-Tissue Expression (GTEx) dataset were used to further select TAMs marker genes. Subsequently, a TAMRG-score was constructed by Least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox regression analysis in the TCGA dataset and validated in the Chinese Glioma Genome Atlas (CGGA) dataset.

RESULTS

We identified 186 TAMs marker genes, and a total of 6 optimal prognostic genes including CKS2, LITAF, CTSB, TWISTNB, PPIF and G0S2 were selected to construct a TAMRG-score. The high TAMRG-score was significantly associated with worse prognosis (log-rank test, P<0.001). Moreover, the TAMRG-score outperformed the other three models with AUC of 0.808. Immune cell infiltration, TME scores, immune checkpoints, TMB and drug susceptibility were significantly different between TAMRG-score groups. In addition, a nomogram were constructed by combing the TAMRG-score and clinical information (Age, Grade, IDH mutation and 1p19q codeletion) to predict the survival of glioma patients with AUC of 0.909 for 1-year survival.

CONCLUSION

The high TAMRG-score group was associated with a poor prognosis. A nomogram by incorporating TMARG-score could precisely predict glioma survival, and provide evidence for personalized treatment of glioma.

Tissue-specific features of innate lymphoid cells in antiviral defense

Innate lymphocytes (ILCs) rapidly respond to and protect against invading pathogens and cancer. ILCs include natural killer (NK) cells, ILC1s, ILC2s, ILC3s, and lymphoid tissue inducer (LTi) cells and include type I, type II, and type III immune cells. While NK cells have been well recognized for their role in antiviral immunity, other ILC subtypes are emerging as players in antiviral defense. Each ILC subset has specialized functions that uniquely impact the antiviral immunity and health of the host depending on the tissue microenvironment. This review focuses on the specialized functions of each ILC subtype and their roles in antiviral immune responses across tissues. Several viruses within infection-prone tissues will be highlighted to provide an overview of the extent of the ILC immunity within tissues and emphasize common versus virus-specific responses.

The role of trained immunity in sepsis

Sepsis is defined as a life-threatening organ dysfunction syndrome caused by dysregulated host response to infection, characterized by a systemic inflammatory response to infection. The use of antibiotics, fluid resuscitation, and organ support therapy has limited prognostic benefit in patients with sepsis, and its incidence is not diminishing, which is attracting increased attention in medicine. Sepsis remains one of the most debilitating and expensive illnesses. One of the main reasons of septic mortality is now understood to be disruption of immune homeostasis. Immunotherapy is revolutionizing the treatment of illnesses in which dysregulated immune responses play a significant role. This "trained immunity", which is a potent defense against infection regardless of the type of bacteria, fungus, or virus, is attributed to the discovery that the innate immune cells possess immune memory via metabolic and epigenetic reprogramming. Here we reviewed the immunotherapy of innate immune cells in sepsis, the features of trained immunity, and the relationship between trained immunity and sepsis.

Urine scRNAseq reveals new insights into the bladder tumor immune microenvironment

Due to bladder tumors' contact with urine, urine-derived cells (UDCs) may serve as a surrogate for monitoring the tumor microenvironment (TME) in bladder cancer (BC). However, the composition of UDCs and the extent to which they mirror the tumor remain poorly characterized. We generated the first single-cell RNA-sequencing of BC patient UDCs with matched tumor and peripheral blood mononuclear cells (PBMC). BC urine was more cellular than healthy donor (HD) urine, containing multiple immune populations including myeloid cells, CD4+ and CD8+ T cells, natural killer (NK) cells, B cells, and dendritic cells (DCs) in addition to tumor and stromal cells. Immune UDCs were transcriptionally more similar to tumor than blood. UDCs encompassed cytotoxic and activated CD4+ T cells, exhausted and tissue-resident memory CD8+ T cells, macrophages, germinal-center-like B cells, tissue-resident and adaptive NK cells, and regulatory DCs found in tumor but lacking or absent in blood. Our findings suggest BC UDCs may be surrogates for the TME and serve as therapeutic biomarkers.

Beyond CAR-T: The rise of CAR-NK cell therapy in asthma immunotherapy

Asthma poses a major public health burden. While existing asthma drugs manage symptoms for many, some patients remain resistant. The lack of a cure, especially for severe asthma, compels exploration of novel therapies. Cancer immunotherapy successes with CAR-T cells suggest its potential for asthma treatment. Researchers are exploring various approaches for allergic diseases including membrane-bound IgE, IL-5, PD-L2, and CTLA-4 for asthma, and Dectin-1 for fungal asthma. NK cells offer several advantages over T cells for CAR-based immunotherapy. They offer key benefits: (1) HLA compatibility, meaning they can be used in a wider range of patients without the need for matching tissue types. (2) Minimal side effects (CRS and GVHD) due to their limited persistence and cytokine profile. (3) Scalability for "off-the-shelf" production from various sources. Several strategies have been introduced that highlight the superiority and challenges of CAR-NK cell therapy for asthma treatment including IL-10, IFN-γ, ADCC, perforin-granzyme, FASL, KIR, NCRs (NKP46), DAP, DNAM-1, TGF-β, TNF-α, CCL, NKG2A, TF, and EGFR. Furthermore, we advocate for incorporating AI for CAR design optimization and CRISPR-Cas9 gene editing technology for precise gene manipulation to generate highly effective CAR constructs. This review will delve into the evolution and production of CAR designs, explore pre-clinical and clinical studies of CAR-based therapies in asthma, analyze strategies to optimize CAR-NK cell function, conduct a comparative analysis of CAR-T and CAR-NK cell therapy with their respective challenges, and finally present established novel CAR designs with promising potential for asthma treatment.

Pan-cancer profiling of tumor-infiltrating natural killer cells through transcriptional reference mapping

The functional diversity of natural killer (NK) cell repertoires stems from differentiation, homeostatic, receptor-ligand interactions and adaptive-like responses to viral infections. In the present study, we generated a single-cell transcriptional reference map of healthy human blood- and tissue-derived NK cells, with temporal resolution and fate-specific expression of gene-regulatory networks defining NK cell differentiation. Transfer learning facilitated incorporation of tumor-infiltrating NK cell transcriptomes (39 datasets, 7 solid tumors, 427 patients) into the reference map to analyze tumor microenvironment (TME)-induced perturbations. Of the six functionally distinct NK cell states identified, a dysfunctional stressed CD56bright state susceptible to TME-induced immunosuppression and a cytotoxic TME-resistant effector CD56dim state were commonly enriched across tumor types, the ratio of which was predictive of patient outcome in malignant melanoma and osteosarcoma. This resource may inform the design of new NK cell therapies and can be extended through transfer learning to interrogate new datasets from experimental perturbations or disease conditions.

A novel NKp80-based strategy for universal identification of normal, reactive and tumor/clonal natural killer-cells in blood

Purpose

Natural killer (NK) cells are traditionally identified by flow cytometry using a combination of markers (CD16/CD56/CD3), because a specific NK-cell marker is still missing. Here we investigated the utility of CD314, CD335 and NKp80, compared to CD16/CD56/CD3, for more robust identification of NK-cells in human blood, for diagnostic purposes.

Methods

A total of 156 peripheral blood (PB) samples collected from healthy donors (HD) and patients with diseases frequently associated with loss/downregulation of classical NK-cell markers were immunophenotyped following EuroFlow protocols, aimed at comparing the staining profile of total blood NK-cells for CD314, CD335 and NKp80, and the performance of distinct marker combinations for their accurate identification.

Results

NKp80 showed a superior performance (vs. CD314 and CD335) for the identification of NK-cells in HD blood. Besides, NKp80 improved the conventional CD16/CD56/CD3-based strategy to identify PB NK-cells in HD and reactive processes, particularly when combined with CD16 for further accurate NK-cell-subsetting. Although NKp80+CD16 improved the identification of clonal/tumor NK-cells, particularly among CD56- cases (53%), aberrant downregulation of NKp80 was observed in 25% of patients, in whom CD56 was useful as a complementary NK-cell marker. As NKp80 is also expressed on T-cells, we noted increased numbers of NKp80+ cytotoxic T-cells at the more advanced maturation stages, mostly in adults.

Conclusion

Here we propose a new robust approach for the identification of PB NK-cells, based on the combination of NKp80 plus CD16. However, in chronic lymphoproliferative disorders of NK-cells, addition of CD56 is recommended to identify clonal NK-cells, due to their frequent aberrant NKp80- phenotype.

Insights into the Roles of Natural Killer Cells in Osteoarthritis

Osteoarthritis (OA) is now widely acknowledged as a low-grade inflammatory condition, in which the intrinsic immune system plays a significant role in its pathogenesis. While the involvement of macrophages and T cells in the development of OA has been extensively reviewed, recent research has provided mounting evidence supporting the crucial contribution of NK cells in both the initiation and advancement of OA. Accumulated evidence has emerged in recent years indicating that NK cells play a critical role in OA development and progression. This review will outline the ongoing understanding of the utility of NK cells in the etiology of OA, focusing on how NK cells interact with chondrocytes, synoviocytes, osteoclasts, and other immune cells to influence the course of OA disease.

Distinct developmental pathways generate functionally distinct populations of natural killer cells

Natural killer (NK) cells function by eliminating virus-infected or tumor cells. Here we identified an NK-lineage-biased progenitor population, referred to as early NK progenitors (ENKPs), which developed into NK cells independently of common precursors for innate lymphoid cells (ILCPs). ENKP-derived NK cells (ENKP_NK cells) and ILCP-derived NK cells (ILCP_NK cells) were transcriptionally different. We devised combinations of surface markers that identified highly enriched ENKP_NK and ILCP_NK cell populations in wild-type mice. Furthermore, Ly49H+ NK cells that responded to mouse cytomegalovirus infection primarily developed from ENKPs, whereas ILCP_NK cells were better IFNγ producers after infection with Salmonella and herpes simplex virus. Human CD56dim and CD56bright NK cells were transcriptionally similar to ENKP_NK cells and ILCP_NK cells, respectively. Our findings establish the existence of two pathways of NK cell development that generate functionally distinct NK cell subsets in mice and further suggest these pathways may be conserved in humans.

Dysfunctional natural killer cells can be reprogrammed to regain anti-tumor activity

Natural killer (NK) cells are critical to the innate immune system, as they recognize antigens without prior sensitization, and contribute to the control and clearance of viral infections and cancer. However, a significant proportion of NK cells in mice and humans do not express classical inhibitory receptors during their education process and are rendered naturally "anergic", i.e., exhibiting reduced effector functions. The molecular events leading to NK cell anergy as well as their relation to those underlying NK cell exhaustion that arises from overstimulation in chronic conditions, remain unknown. Here, we characterize the "anergic" phenotype and demonstrate functional, transcriptional, and phenotypic similarities to the "exhausted" state in tumor-infiltrating NK cells. Furthermore, we identify zinc finger transcription factor Egr2 and diacylglycerol kinase DGKα as common negative regulators controlling NK cell dysfunction. Finally, experiments in a 3D organotypic spheroid culture model and an in vivo tumor model suggest that a nanoparticle-based delivery platform can reprogram these dysfunctional natural killer cell populations in their native microenvironment. This approach may become clinically relevant for the development of novel anti-tumor immunotherapeutic strategies.

Intraepithelial CD15 infiltration identifies high-grade anal dysplasia in people with HIV

Men who have sex with men (MSM) with HIV are at high risk for squamous intraepithelial lesion (SIL) and anal cancer. Identifying local immunological mechanisms involved in the development of anal dysplasia could aid treatment and diagnostics. Here, we studied 111 anal biopsies obtained from 101 MSM with HIV, who participated in an anal screening program. We first assessed multiple immune subsets by flow cytometry, in addition to histological examination, in a discovery cohort. Selected molecules were further evaluated by immunohistochemistry in a validation cohort. Pathological samples were characterized by the presence of resident memory T cells with low expression of CD103 and by changes in natural killer cell subsets, affecting residency and activation. Furthermore, potentially immunosuppressive subsets, including CD15+CD16+ mature neutrophils, gradually increased as the anal lesion progressed. Immunohistochemistry verified the association between the presence of CD15 in the epithelium and SIL diagnosis for the correlation with high-grade SIL. A complex immunological environment with imbalanced proportions of resident effectors and immune-suppressive subsets characterized pathological samples. Neutrophil infiltration, determined by CD15 staining, may represent a valuable pathological marker associated with the grade of dysplasia.

Human γδ T cells in diverse tissues exhibit site-specific maturation dynamics across the life span

During ontogeny, γδ T cells emerge from the thymus and directly seed peripheral tissues for in situ immunity. However, their functional role in humans has largely been defined from blood. Here, we analyzed the phenotype, transcriptome, function, and repertoire of human γδ T cells in blood and mucosal and lymphoid tissues from 176 donors across the life span, revealing distinct profiles in children compared with adults. In early life, clonally diverse Vδ1 subsets predominate across blood and tissues, comprising naïve and differentiated effector and tissue repair functions, whereas cytolytic Vδ2 subsets populate blood, spleen, and lungs. With age, Vδ1 and Vδ2 subsets exhibit clonal expansions and elevated cytolytic signatures, which are disseminated across sites. In adults, Vδ2 cells predominate in blood, whereas Vδ1 cells are enriched across tissues and express residency profiles. Thus, antigenic exposures over childhood drive the functional evolution and tissue compartmentalization of γδ T cells, leading to age-dependent roles in immunity.

Dynamic immune status analysis of peripheral blood mononuclear cells in patients with Klebsiella pneumoniae bloodstream infection sepsis using single-cell RNA sequencing

Background

Klebsiella pneumoniae is a common Gram-negative bacterium. Blood infection caused by K. pneumoniae is one of the most common causes of human sepsis, which seriously threatens the life of patients. The immune status of peripheral blood mononuclear cells (PBMCs) based on single-cell RNA sequencing (scRNA-seq) in acute stage and recovery stage of sepsis caused by K. pneumoniae bloodstream infection has not been studied.

Methods

A total of 13 subjects were included in this study, 3 healthy controls, 7 patients with K. pneumoniae bloodstream infection in the acute stage (4 patients died), and 3 patients in the recovery stage. Peripheral blood of all patients was collected and PBMCs were isolated for scRNA-seq analysis. We studied the changes of PBMCs components, signaling pathways, differential genes, and cytokines in acute and recovery stages.

Results

During K. pneumoniae acute infection we observed a decrease in the proportion of T cells, most probably due to apoptosis and the function of T cell subtypes was disorder. The proportion of monocytes increased in acute stage. Although genes related to their phagocytosis function were upregulated, their antigen presentation capacity-associated genes were downregulated. The expression of IL-1β, IL-18, IFNGR1 and IFNGR2 genes was also increased in monocytes. The proportion of DCs was depleted during the acute stage and did not recover during sepsis recovery. DCs antigen presentation was weakened during the acute stage but recovered fast during the recovery stage. pDCs response to MCP-1 chemokine was weakened, they recovered it quickly during the recovery stage. B cells showed apoptosis both in the acute stage and recovery stage. Their response to complement was weakened, but their antigen presentation function was enhanced. The proportion of NK cells stable during all disease's stages, and the expression of IFN-γ gene was upregulated.

Conclusion

The proportion of PBMCs and their immune functions undergo variations throughout the course of the disease, spanning from the acute stage to recovery. These findings provide new insights into the mechanism of PBMCs immune function during K. pneumoniae bloodstream infection sepsis and recovery and sets the basis for further understanding and treatment.

Cellular senescence, DNA damage, and neuroinflammation in the aging brain

Aging may lead to low-level chronic inflammation that increases the susceptibility to age-related conditions, including memory impairment and progressive loss of brain volume. As brain health is essential to promoting healthspan and lifespan, it is vital to understand age-related changes in the immune system and central nervous system (CNS) that drive normal brain aging. However, the relative importance, mechanistic interrelationships, and hierarchical order of such changes and their impact on normal brain aging remain to be clarified. Here, we synthesize accumulating evidence that age-related DNA damage and cellular senescence in the immune system and CNS contribute to the escalation of neuroinflammation and cognitive decline during normal brain aging. Targeting cellular senescence and immune modulation may provide a logical rationale for developing new treatment options to restore immune homeostasis and counteract age-related brain dysfunction and diseases.

NK cells as powerful therapeutic tool in cancer immunotherapy

BACKGROUND

Natural killer (NK) cells have gained considerable attention and hold great potential for their application in tumor immunotherapy. This is mainly due to their MHC-unrestricted and pan-specific recognition capabilities, as well as their ability to rapidly respond to and eliminate target cells. To artificially generate therapeutic NK cells, various materials can be utilized, such as peripheral blood mononuclear cells (PBMCs), umbilical cord blood (UCB), induced pluripotent stem cells (iPSCs), and NK cell lines. Exploiting the therapeutic potential of NK cells to treat tumors through in vivo and in vitro therapeutic modalities has yielded positive therapeutic results.

CONCLUSION

This review provides a comprehensive description of NK cell therapeutic approaches for tumors and discusses the current problems associated with these therapeutic approaches and the prospects of NK cell therapy for tumors.