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Non-Alcoholic Steatohepatitis (NASH) is the progressive form of Non-Alcoholic Fatty Liver Disease (NAFLD), the main cause of chronic liver complications. The development of NASH is the consequence of aberrant activation of hepatic conventional immune, parenchymal, and endothelial cells in response to inflammatory mediators from the liver, adipose tissue, and gut. Hepatocytes, Kupffer cells and liver sinusoidal endothelial cells contribute to the significant accumulation of bone-marrow derived-macrophages and neutrophils in the liver, a hallmark of NASH. The aberrant activation of these immune cells elicits harmful inflammation and liver injury, leading to NASH progression. In this review, we highlight the processes triggering the recruitment and/or activation of hepatic innate immune cells, with a focus on macrophages, neutrophils, and innate lymphoid cells as well as the contribution of hepatocytes and endothelial cells in driving liver inflammation/fibrosis. On-going studies and preliminary results from global and specific therapeutic strategies to manage this NASH-related inflammation will also be discussed.

The lung is a primary organ for gas exchange in mammals that represents the largest epithelial surface in direct contact with the external environment. It also serves as a crucial immune organ, which harbors both innate and adaptive immune cells to induce a potent immune response. Due to its direct contact with the outer environment, the lung serves as a primary target organ for many airborne pathogens, toxicants (aerosols), and allergens causing pneumonia, acute respiratory distress syndrome (ARDS), and acute lung injury or inflammation (ALI). The current review describes the immunological mechanisms responsible for bacterial pneumonia and sepsis-induced ALI. It highlights the immunological differences for the severity of bacterial sepsis-induced ALI as compared to the pneumonia-associated ALI. The immune-based differences between the Gram-positive and Gram-negative bacteria-induced pneumonia show different mechanisms to induce ALI. The role of pulmonary epithelial cells (PECs), alveolar macrophages (AMs), innate lymphoid cells (ILCs), and different pattern-recognition receptors (PRRs, including Toll-like receptors (TLRs) and inflammasome proteins) in neutrophil infiltration and ALI induction have been described during pneumonia and sepsis-induced ALI. Also, the resolution of inflammation is frequently observed during ALI associated with pneumonia, whereas sepsis-associated ALI lacks it. Hence, the review mainly describes the different immune mechanisms responsible for pneumonia and sepsis-induced ALI. The differences in immune response depending on the causal pathogen (Gram-positive or Gram-negative bacteria) associated pneumonia or sepsis-induced ALI should be taken in mind specific immune-based therapeutics.

Innate lymphoid cells (ILCs) are largely tissue resident and respond rapidly toward the environmental signals from surrounding tissues and other immune cells. The pleiotropic function of ILCs in diverse contexts underpins its importance in the innate arm of immune system in human health and disease. ILCs derive from common lymphoid progenitors but lack adaptive antigen receptors and functionally act as the innate counterpart to T-cell subsets. The classification of different subtypes is based on their distinct transcription factor requirement for development as well as signature cytokines that they produce. The discovery and subsequent characterization of ILCs over the past decade have mainly focused on the regulation of inflammation, tissue remodeling, and homeostasis, whereas the understanding of the multiple roles and mechanisms of ILCs in cancer is still limited. Emerging evidence of the potent immunomodulatory properties of ILCs in early host defense signifies a major advance in the use of ILCs as promising targets in cancer immunotherapy. In this review, we will decipher the non-exclusive roles of ILCs associated with both protumor and antitumor activities. We will also dissect the heterogeneity, plasticity, genetic evidence, and dysregulation in different cancer contexts, providing a comprehensive understanding of the complexity and diversity. These will have implications for the therapeutic targeting in cancer.

Tuberculosis (TB) is currently the deadliest infectious disease worldwide. Failure to create a highly effective vaccine has limited the control of the TB epidemic. Historically, the vaccine field has relied on the paradigm that IFN-γ-mediated CD4+ T cell memory responses are the principal correlate of protection in TB. Nonetheless, the demonstration that other cellular subsets offer protective memory responses against Mycobacterium tuberculosis (Mtb) is emerging. Among these are memory-like features of macrophages, myeloid cell precursors, natural killer (NK) cells, and innate lymphoid cells (ILCs). Additionally, the dynamics of B cell memory responses have been recently characterized at different stages of the clinical spectrum of Mtb infection, suggesting a role for B cells in human TB. A better understanding of the immune mechanisms underlying such responses is crucial to better comprehend protective immunity in TB. Furthermore, targeting immune compartments other than CD4+ T cells in TB vaccine strategies may benefit a significant proportion of patients co-infected with Mtb and the human immunodeficiency virus (HIV). Here, we summarize the memory responses of innate immune cells and B cells against Mtb and propose them as novel correlates of protection that could be harnessed in future vaccine development programs.

A successful pregnancy requires many physiological adaptations from the mother, including the establishment of tolerance toward the semiallogeneic fetus. Innate lymphoid cells (ILCs) have arisen as important players in immune regulation and tissue homeostasis at mucosal and barrier surfaces. Dimensionality reduction and transcriptomic analysis revealed the presence of two novel CD56Bright decidual ILCs that express low T-bet and divergent Eomes levels. Transcriptional correlation with recently identified first trimester decidual dNKs suggests that these novel decidual ILCs might be present throughout pregnancy. Functional testing with permutation analysis revealed production of multiple factors by individual cells, with a preference for IFNγ and VEGF. Overall, our data suggests continuity of a unique decidual innate lymphocytes across pregnancy with a polyfunctional functional profile conducive for pregnancy

Non-Alcoholic Steatohepatitis (NASH) is the progressive form of Non-Alcoholic Fatty Liver Disease (NAFLD), the main cause of chronic liver complications. The development of NASH is the consequence of aberrant activation of hepatic conventional immune, parenchymal, and endothelial cells in response to inflammatory mediators from the liver, adipose tissue, and gut. Hepatocytes, Kupffer cells and liver sinusoidal endothelial cells contribute to the significant accumulation of bone-marrow derived-macrophages and neutrophils in the liver, a hallmark of NASH. The aberrant activation of these immune cells elicits harmful inflammation and liver injury, leading to NASH progression. In this review, we highlight the processes triggering the recruitment and/or activation of hepatic innate immune cells, with a focus on macrophages, neutrophils, and innate lymphoid cells as well as the contribution of hepatocytes and endothelial cells in driving liver inflammation/fibrosis. On-going studies and preliminary results from global and specific therapeutic strategies to manage this NASH-related inflammation will also be discussed. [ABSTRACT FROM AUTHOR]

The lung is a primary organ for gas exchange in mammals that represents the largest epithelial surface in direct contact with the external environment. It also serves as a crucial immune organ, which harbors both innate and adaptive immune cells to induce a potent immune response. Due to its direct contact with the outer environment, the lung serves as a primary target organ for many airborne pathogens, toxicants (aerosols), and allergens causing pneumonia, acute respiratory distress syndrome (ARDS), and acute lung injury or inflammation (ALI). The current review describes the immunological mechanisms responsible for bacterial pneumonia and sepsis-induced ALI. It highlights the immunological differences for the severity of bacterial sepsis-induced ALI as compared to the pneumonia-associated ALI. The immune-based differences between the Gram-positive and Gram-negative bacteria-induced pneumonia show different mechanisms to induce ALI. The role of pulmonary epithelial cells (PECs), alveolar macrophages (AMs), innate lymphoid cells (ILCs), and different pattern-recognition receptors (PRRs, including Toll-like receptors (TLRs) and inflammasome proteins) in neutrophil infiltration and ALI induction have been described during pneumonia and sepsis-induced ALI. Also, the resolution of inflammation is frequently observed during ALI associated with pneumonia, whereas sepsis-associated ALI lacks it. Hence, the review mainly describes the different immune mechanisms responsible for pneumonia and sepsis-induced ALI. The differences in immune response depending on the causal pathogen (Gram-positive or Gram-negative bacteria) associated pneumonia or sepsis-induced ALI should be taken in mind specific immune-based therapeutics. [ABSTRACT FROM AUTHOR]

Problem: Innate lymphoid cells (ILCs, including NK cells) and their subsets are the most frequent lymphocytes at the maternal‐fetal interface (decidua). Recent recognition of extensive ILC subset diversity at mucosal sites and the possible role they might play at different stages of pregnancy poses questions about their composition and lineage stability. Namely, RORγt‐dependent ILC3s have been recognized as a key cellular mediator of tissue organization in the gut and secondary lymphoid organs, prompting examination of their distribution and role in decidua during pregnancy. Method of study: We employed highly polychromatic flow cytometry with conventional and machine learning‐aided analysis to map ILC subsets and dissected the role of canonical transcription factor RORγt using fate‐mapping animals and RORγt−/− animals. Results: We demonstrate a comprehensive immunome map of ILCs/NKs, revealing a dynamic interface even in the absence of antigenic or allogeneic challenge. Strikingly, we demonstrate plasticity of RORγt expression in decidual ILCs with across gestation. However, gross reproductive efficiency is not affected in RORγt−/− animals. Conclusion: These results indicated that RORγt+ ILCs are highly plastic at the maternal‐fetal interface, but dispensable for normal pregnancy, revealing a novel mechanism of transcriptional immunoregulation in pregnancy. [ABSTRACT FROM AUTHOR]

Innate lymphoid cells (ILCs) are the latest identified innate immune cell family. Given their similarity in transcription factor expression and cytokine secretion profiles, ILCs have been considered as the innate phenocopy of CD4 Th cells. Here, we explored the transcriptome of circulating human ILC subsets as opposed to CD4 Th cell subsets. We describe transcriptomic differences between total ILCs and total CD4 Th cells, as well as between paired innate and adaptive cell subsets (ILC1 vs. Th1; ILC2 vs. Th2; and ILC3 vs. Th17 cells). In particular, we observed differences in expression of genes involved in cell trafficking such as CCR1, CCR6 and CXCR3, innate activation and inhibitory functions, including CD119, 2B4, TIGIT, and CTLA‐4, and neuropeptide receptors, such as VIPR2. Moreover, we report for the first time on distinct expression of long noncoding RNAs (lncRNAs) in innate vs. adaptive cells, arguing for a potential role of lncRNA in shaping human ILC biology. Altogether, our results point for unique, rather than redundant gene organization in ILCs compared to CD4 Th cells, in regard to kinetics, fine‐tuning and spatial organization of the immune response. [ABSTRACT FROM AUTHOR]

Innate lymphoid cells (ILCs) are a relatively new class of innate immune cells with phenotypical characters of lymphocytes but genotypically or functionally behave as typical innate immune cells. They have been classically divided into 3 groups (group 1 ILCs or ILC1s, group 2 ILCs or ILC2s, and group 3 ILCs or ILC3s). They serve as the first line of defense against invading pathogens and allergens at mucosal surfaces. The adaptive immune response works effectively in association with innate immunity as innate immune cells serve as APCs to directly stimulate the adaptive immune cells (various sets of T and B cells). Additionally, innate immune cells also secrete various effector molecules, including cytokines or chemokines impacting the function, differentiation, proliferation, and reprogramming among adaptive immune cells to maintain immune homeostasis. Only superantigens do not require their processing by innate immune cells as they are recognized directly by T cells and B cells. Thus, a major emphasis of the current article is to describe the cross‐talk between different ILCs and adaptive immune cells during different conditions varying from normal physiological situations to different infectious diseases to allergic asthma. [ABSTRACT FROM AUTHOR]

Innate lymphoid cells (ILCs) are largely tissue resident and respond rapidly toward the environmental signals from surrounding tissues and other immune cells. The pleiotropic function of ILCs in diverse contexts underpins its importance in the innate arm of immune system in human health and disease. ILCs derive from common lymphoid progenitors but lack adaptive antigen receptors and functionally act as the innate counterpart to T-cell subsets. The classification of different subtypes is based on their distinct transcription factor requirement for development as well as signature cytokines that they produce. The discovery and subsequent characterization of ILCs over the past decade have mainly focused on the regulation of inflammation, tissue remodeling, and homeostasis, whereas the understanding of the multiple roles and mechanisms of ILCs in cancer is still limited. Emerging evidence of the potent immunomodulatory properties of ILCs in early host defense signifies a major advance in the use of ILCs as promising targets in cancer immunotherapy. In this review, we will decipher the non-exclusive roles of ILCs associated with both protumor and antitumor activities. We will also dissect the heterogeneity, plasticity, genetic evidence, and dysregulation in different cancer contexts, providing a comprehensive understanding of the complexity and diversity. These will have implications for the therapeutic targeting in cancer. [ABSTRACT FROM AUTHOR]

A successful pregnancy requires many physiological adaptations from the mother, including the establishment of tolerance toward the semiallogeneic fetus. Innate lymphoid cells (ILCs) have arisen as important players in immune regulation and tissue homeostasis at mucosal and barrier surfaces. Dimensionality reduction and transcriptomic analysis revealed the presence of two novel CD56Bright decidual ILCs that express low T-bet and divergent Eomes levels. Transcriptional correlation with recently identified first trimester decidual dNKs suggests that these novel decidual ILCs might be present throughout pregnancy. Functional testing with permutation analysis revealed production of multiple factors by individual cells, with a preference for IFNγ and VEGF. Overall, our data suggests continuity of a unique decidual innate lymphocytes across pregnancy with a polyfunctional functional profile conducive for pregnancy [ABSTRACT FROM AUTHOR]

It is assumed that cells corresponding to innate lymphoid cells (ILCs) in humans, in addition to lymphoid tissue inducer cells (LTi), are also found in teleosts. In this systematic group of organisms, however, they are a poorly understood cell population. In contrast to the data on ILCs in humans, which also remain incomplete despite advanced research, in teleosts, these cells require much more attention. ILCs in teleosts have been presented as cells that may be evolutionary precursors of NK cells or ILCs identified in mammals, including humans. It is a highly heterogeneous group of cells in both humans and fish and their properties, as revealed by studies in humans, are most likely to remain strictly dependent on the location of these cells and the physiological state of the individual from which they originate. They form a bridge between innate and adaptive immunity. The premise of this paper is to review the current knowledge of ILCs in teleosts, taking into account data on similar cells in humans. A review of the knowledge concerning these particular cells, elements of innate immunity mechanisms as equivalent to, or perhaps dominant over, adaptive immunity mechanisms in teleosts, as presented, may inspire the need for further research. • Innate lymphoid cells (ILCs) are identified in teleost fish. • The population of ILCs in fish consists of NK cells, ILC1, ILC2, ILC3. • Fish ILCs express cytokines that induce type 1, 2 and 3 immunity. • The properties of ILCs in fish are determined, among other things, by their location. [ABSTRACT FROM AUTHOR]

Innate lymphoid cells (ILCs) are innate counterparts of T cells that contribute to immune responses by secreting effector cytokines and regulating the functions of other innate and adaptive immune cells. ILCs carry out some unique functions but share some tasks with T cells. ILCs are present in lymphoid and non-lymphoid organs and are particularly abundant at the mucosal barriers, where they are exposed to allergens, commensal microbes, and pathogens. The impact of ILCs in mucosal immune responses has been extensively investigated in the gastrointestinal and respiratory tracts, as well as in the oral cavity. Here we review the state-of-the-art knowledge of ILC functions in infections, allergy and autoimmune disorders of the mucosal barriers.

Background: ILCs play important roles in the brain, gut, and lungs. Researchers are attempting to establish a research framework on the brain-gut-lung axis using ILCs. However, no one has yet conducted a bibliometric analysis to summarize the findings. In this study, we utilized bibliometrics to analyze the emerging trends and focal areas of ILCs in the brain, intestine, and lung. We aim to provide references for future research on the brain-gut-lung axis., Methods: To conduct a comprehensive bibliometric analysis on ILCs in the fields of brain, intestine, and lung, we utilized software such as HistCite, VOSviewer, and CiteSpace. Our analysis focused on various aspects, including the number of publications, countries, authors, journals, co-cited documents, and keywords. This approach allowed us to gain valuable insights into the research landscape surrounding ILCs in these specific fields., Results: A total of 8411 articles or reviews on ILCs in the fields of brain, intestine, and lung were included. The number of published articles has shown a consistent upward trend since 2003. A total of 45279 authors from 99 countries have contributed to these articles. The United States has the highest number of publications (n=3044) and the most cited articles (TGCS=210776). The top three published authors in this field are David Artis, Marco Colonna and Andrew NJ McKenzie. The journal Immunity is the most authoritative choice for researchers. The main research focuses in this field include NK cell, ILC2, tumor immunity, multiple sclerosis, inflammatory bowel disease, airway inflammation, RORγT, and immunotherapy. In recent years, cancer and tumor microenvironment have emerged as hot keywords, particularly immunotherapy, PD-1 related directions, indicating a potential shift in research focus., Conclusion: European and American countries have been pivotal in conducting research on ILCs, while China has produced a significant number of publications, its impact is still limited. Tumors are likely to emerge as the next focal points in this field. The connection and regulation between the brain and the lung are not yet fully understood, and further investigation is necessary to explore the role of ILCs in the brain-lung axis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Huang, Deng, Liu, Xia, Lei and Wu.)

Skeletal abnormalities are common comorbidities of inflammatory bowel disease (IBD). Patients suffering from IBD, including ulcerative colitis and Crohn's disease, present with skeletal complications. However, the mechanism underpinning IBD‐associated bone loss remains vague. Intestinal inflammation generates an inflammatory milieu at the intestinal epithelium that leads to dysregulation of mucosal immunity through gut‐residing innate lymphoid cells (ILCs) and other cell types. ILCs are recently identified mucosal cells considered as the gatekeeper of gut immunity and their function is regulated by intestinal epithelial cell (IEC)‐secreted cytokines in response to the inflammatory microenvironment. We first demonstrate that serum as well as IECs collected from the intestine of dextran sulfate sodium (DSS)‐induced colitis mice contain high levels of inflammatory and osteoclastogenic cytokines. Mechanistically, heightened inflammatory response of IECs was associated with significant intrinsic activation of NF‐κB (nuclear factor kappa‐light‐chain‐enhancer of activated B cells) in IECs and increased frequency of ILC1, ILC3, and myeloid osteoclast progenitors. Validating the central role of IEC‐specific NF‐κB activation in this phenomenon, conditional expression of constitutively active inhibitor kappa B kinase 2 (IKK2) in IECs in mice recapitulates the majority of the cellular, inflammatory, and osteolytic phenotypes observed in the chemically induced colitis. Furthermore, conditional deletion of IKK2 from IECs significantly attenuated inflammation and bone loss in DSS‐induced colitis. Finally, using the DSS‐induced colitis model, pharmacologic inhibition of IKK2 was effective in reducing frequency of ILC1 and ILC3 cells, attenuated circulating levels of inflammatory cytokines, and halted colitis‐associated bone loss. Our findings identify IKK2 in IECs as viable therapeutic target for colitis‐associated osteopenia. [ABSTRACT FROM AUTHOR]

Alterations in the composition of the intestinal microbiota have been associated with development of type 1 diabetes (T1D), but little is known about changes in intestinal homeostasis that contribute to disease pathogenesis. Here, we analyzed oral tolerance induction, components of the intestinal barrier, fecal microbiota, and immune cell phenotypes in non‐obese diabetic (NOD) mice during disease progression compared to non‐obese diabetes resistant (NOR) mice. NOD mice failed to develop oral tolerance and had defective protective/regulatory mechanisms in the intestinal mucosa, including decreased numbers of goblet cells, diminished mucus production, and lower levels of total and bacteria‐bound secretory IgA, as well as an altered IEL profile. These disturbances correlated with bacteria translocation to the pancreatic lymph node possibly contributing to T1D onset. The composition of the fecal microbiota was altered in pre‐diabetic NOD mice, and cross‐fostering of NOD mice by NOR mothers corrected their defect in mucus production, indicating a role for NOD microbiota in gut barrier dysfunction. NOD mice had a reduction of CD103+ dendritic cells (DCs) in the MLNs, together with an increase of effector Th17 cells and ILC3, as well as a decrease of Th2 cells, ILC2, and Treg cells in the small intestine. Importantly, most of these gut alterations precede the onset of insulitis. Disorders in the intestinal mucosa of NOD mice can potentially interfere with the development of T1D due the close relationship between the gut and the pancreas. Understanding these early alterations is important for the design of novel therapeutic strategies for T1D prevention. [ABSTRACT FROM AUTHOR]

• Innate lymphoid cell subsets are involved in protection against cancer. • NK cells have an intrinsic ability to detect and kill cancer cells. • NK cell development and effector activity is regulated by the cytokine interleukin-15. • SOCS proteins function as immune checkpoints in tumor immunity. Immune checkpoint inhibitors harness the power of the immune system to fight cancer. The clinical success achieved with antibodies against the inhibitory T cell receptors PD-1 and CTLA4 has focused attention on the possibility of manipulating other immune cells, in particular those involved in innate immunity. Here we review the role of innate lymphoid cells (ILCs) and their contribution to tumor immunity. As the prototypical ILC, the natural killer (NK) cell has an intrinsic ability to detect and kill cancer cells. NK cells are dependent on the cytokine interleukin (IL)-15 for their development and effector activity. We discuss the role of the Suppressor of cytokine (SOCS) proteins in negatively regulating IL-15 and NK cell responses and the potential for targeting these small intracellular regulators as new immune checkpoints. [ABSTRACT FROM AUTHOR]

• ILC and Th17 cell populations are enriched at mucosal surfaces. • IL-17 and IL-22 are signature ILC3 and Th17 cytokines. • IL-17 and IL-22 are implicated in colorectal cancer progression. • The relative contribution of ILC and Th17-type cytokines to cancer needs to be defined. Innate lymphoid cells (ILCs) contribute to the regulation of gastrointestinal (GI) homeostasis. Over the past 15 years, there has been a large effort to dissect the mechanisms required for GI homeostasis, with a major focus on different immune cell populations and the cytokines that they produce. In contrast to T-helper (Th) cells, ILCs respond rapidly to cytokines in their microenvironment in the absence of specific antigens; however, once activated both cell populations have similar effector functions. Two effector cytokines produced by both ILC3 and Th17 cell populations, Interleukin (IL)-17 and IL-22, have taken center stage for their ability to signal directly to GI epithelial cells and promote epithelial cell survival. In this review, we outline our current understanding of ILCs in the GI tract, and focus on GI cancers associated with aberrant production of IL-17 and IL-22. We highlight evidence from both mouse and patient-based analyses and discuss how tumor cells may hijack the potential evolutionary redundancy of these two cell populations. [ABSTRACT FROM AUTHOR]

Background: Human breast milk cells remain poorly characterized for the presence of unconventional T lymphocytes and innate lymphoid cells (ILCs). Methods: Early breast milk was collected from eight HIV‐uninfected and 11 HIV‐infected women 3‐12 days after delivery. Mucosal‐associated invariant T cells (MAIT cells), TCR γδ cells, and innate lymphoid cells (ILCs) were analyzed in breast milk and paired blood samples. Results: CD161+/TRAV1‐2 + MAIT cells were detected in breast milk, accounting for a median (IQR) of 0.08% (0.06‐0.16) and 0.17% (0.16‐0.31) of CD45+ breast milk cells in HIV‐uninfected and HIV‐infected women, respectively. A selective compartmentalization of γδ T lymphocytes was observed in breast milk. Median (IQR) frequency of γδ T lymphocytes was 8.95% (8.64‐12.14) among breast milk lymphocyte cells compared to 2.54% (1.81‐4.10) in blood (P = 0.03) in HIV‐uninfected women, and 7.26% (4.22‐10.54) in breast milk versus 3.31% (2.54‐3.80) in blood (P = 0.004) from HIV‐infected women. The proportion of group 1 ILC (ILC1) among total ILCs was higher in breast milk compared to blood in HIV‐uninfected women (P = 0.03) and HIV‐infected women (P = 0.001). The frequency of ILC2 among total ILCs tends to be lower in breast milk compared to blood in HIV‐uninfected women (P = 0.06) and HIV‐infected women (P = 0.03). Conclusion: Unconventional T cells and ILCs that may be involved in both the protection against infection of the lactating mammary gland and maturation of infant's gut and microbiomes account for a detectable fraction of breast milk cells. [ABSTRACT FROM AUTHOR]

Purpose of Review: The discovery of innate lymphoid cells (ILCs) over the past decade has reformed principles that were once thought to be exclusive to adaptive immunity. Here, we describe ILC nomenclature and function, and provide a survey of studies examining these cells in the context of HIV/SIV infections. Particular emphasis is placed on the ILC3 subset, important for proper functioning of the gastrointestinal tract barrier. Recent Findings: Studies in both humans and nonhuman primates have found ILCs to be rapidly and durably depleted in untreated HIV/SIV infections. Their depletion is most likely due to a number of bystander effects induced by viral replication. Summary: Given the number of associations observed between loss of ILCs and HIV-related GI damage, their impact on the GI tract is likely important. It may be informative to examine this subset in parallel with other immune cell types when assessing overall health of the GI tract in future studies. [ABSTRACT FROM AUTHOR]

Abstract Asthma is the most prevalent allergic disease of the airway, which is characterized by eosinophilic inflammation, mucus hyperproduction, and airway hyper-responsiveness. Although these pathognomonic features are mainly mediated by antigen-specific Th2 cells and their cytokines, such as IL-4, IL-5, and IL-13, recent studies have revealed that other inflammatory cells, including Th17 cells and innate lymphoid cells (ILCs), also play a critical role in the pathogenesis of asthma. IL-22, one of the cytokines produced by Th17 cells and type 3 ILCs, has distinct functional properties, as IL-22 exclusively acts on non-hematopoietic cells including epithelial cells of mucosal surface and exhibits a broad range of action in regeneration and host protection. In accordance with the fact that lung epithelial cells play a critical role in the pathogenesis of asthma, we and other groups have shown that IL-22 is involved in the regulation of allergic airway inflammation. In this review, we discuss recent advances in the biology of IL-22 and its involvement in the pathogenesis of allergic airway inflammation. [ABSTRACT FROM AUTHOR]

Innate lymphoid cells (ILCs) are the most recently identified family of the innate immune system and are hypothesized to modulate immune functions prior to the generation of adaptive immune responses. Subsets of ILCs reside in the mucosa and regulate immune responses to external pathogens; however, their role and the mechanism by which they protect against intracellular bacterial infection is not completely understood. In this report, using S. typhimurium and L. monocytogenes, we found that the levels of group 1 ILCs and NCR+ ILC3s were increased upon infection and that these increases were associated with Runt-related transcription factor 3 (Runx3) expression. Runx3 fl/fl PLZF-cre mice were much more sensitive to infection with the intracellular bacterial pathogens S. typhimurium and L. monocytogenes partially due to abnormal Group 1 ILC and NCR+ILC3 function. We also found that Runx3 directly binds to the Il12Rβ2 promoter and intron 8 to accelerate the expression of Il12Rβ2 and modulates IFNγ secretion triggered by the IL12/ STAT4 axis. Therefore, we demonstrate that Runx3 influences group 1 ILC- and NCR+ILC3-mediated immune protection against intracellular bacterial infections of both the gut and liver.

The intestinal immune system is challenged daily with the task of recognizing and eliminating pathogens while simultaneously tolerating dietary and commensal antigens. All components must effectively coordinate to differentiate a continual barrage of environmental cues and mount appropriate responses dependent on the nature of the stimuli encountered. Playing a pivotal role, the aryl hydrocarbon receptor (AHR) is a chemical sensor that detects both dietary and microbial cues and is important for development, maintenance, and function of several types of intestinal immune cells, particularly innate lymphoid cells (ILCs) and T cells. In this review, we will highlight recent advances in our knowledge of the role of AHR signaling in ILCs, T cells, B cells, and dendritic cells. [ABSTRACT FROM AUTHOR]

Abstract: T‐bet and Eomes are T‐box transcription factors that drive the differentiation and function of cytotoxic lymphocytes such as NK cells. Their DNA‐binding domains are highly similar, suggesting redundant transcriptional activity. However, while these transcription factors have different patterns of expression, the phenotype of loss‐of‐function mouse models suggests that they play distinct roles in the development of NK cells and other innate lymphoid cells (ILCs). Recent technological advances using reporter mice and conditional knockouts were fundamental in defining the regulation and function of these factors at steady state and during pathological conditions such as various types of cancer or infection. Here, we review these recent developments, focusing on NK cells as prototypical cytotoxic lymphocytes and their development, and also discuss parallels between NK cells and T cells. We also examine the role of T‐bet and Eomes in human NK cells and ILC1s. Considering divergent findings on mouse and human ILC1s, we propose that NK cells are defined by coexpression of T‐bet and Eomes, while ILC1s express only one of these factors, either T‐bet or Eomes, depending on the tissue or the species. [ABSTRACT FROM AUTHOR]

Innate lymphoid cells (ILCs) have been a hot topic in recent research, they are widely distributed in vivo and play an important role in different tissues. The important role of group 2 innate lymphoid cells (ILC2s) in the conversion of white fat into beige fat has attracted widespread attention. Studies have shown that ILC2s regulate adipocyte differentiation and lipid metabolism. This article reviews the types and functions of ILCs, focusing on the relationship between differentiation, development and function of ILC2s, and elaborates on the relationship between peripheral ILC2s and browning of white fat and body energy homeostasis. This has important implications for the future treatment of obesity and related metabolic diseases., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Innate lymphoid cells (ILCs) are identified as novel population of hematopoietic cells which protect the body by coordinating the innate immune response against a wide range of threats including infections, tissue damages and homeostatic disturbances. ILCs, particularly ILC2 cells, are found throughout the body including the brain. ILCs are morphologically similar to lymphocytes, express and release high levels of T-helper (Th)1, Th2 and Th17 cytokines but do not express classical cell-surface markers that are associated with other immune cell lineages.Three types of ILCs (ILC1, 2&3) have been reported depending upon the cytokines produced. ILC1 cells encompass natural killer (NK) cells and interferon (IFN)-g releasing cells; ILC2 cells release the Th2 cytokines, IL-5, IL-9 and IL-13 in response to IL-25 and IL-33; and ILC3 cells which release IL-17 and IL-22. ILC2 cells have been implicated in mucosal reactions occurring in animal models of allergic asthma and virus-induced lung disorders resulting in the regulation of airway remodeling and tissue homeostasis.There is evidence for increased ILC2 cell numbers in allergic responses in man but little is known about the role of ILCs in chronic obstructive pulmonary disease (COPD). Further understanding of the characteristics of ILCs such as their origin, location and phenotypes and function would help to clarify the role of these cells in the pathogenesis of various lung diseases.In this review we will focus on the role of ILC2 cells and consider their origin, function, location and possible role in the pathogenesis of the chronic inflammatory disorders such as asthma and COPD.

Background: Armenians very rarely seek healthcare services and, consequently experience more serious health conditions. With its ongoing reforms, Armenia is focusing on linking health system financing to the quality and volume of care provided. We examine the relationship between the perceived health status of the population and the satisfaction with healthcare services.Methods: A pooled probit model is applied to analyse three datasets (2010, 2011 and 2012) from the Integrated Living Conditions Survey (ILCS).Results: We find a strong association between self-perceived health and satisfaction with healthcare services but this association is not consistent across regions.Conclusions: The socioeconomic position of the household alone does not explain the perception of individual health status. The perceived dwelling condition and geography of residence emerged as important stressors on associations between the perceived health status of the population and the satisfaction with healthcare services. We have modelled the perceived health status and satisfaction with the healthcare services using demand side datasets. This study establishes the need to re-examine this association in a multidimensional construct. [ABSTRACT FROM AUTHOR]

Problem Identification of the types of cells that produce IL-17 and IL-22 in the genital tract can clarify the roles that these cytokines play in responses to pathogens. Method of study We isolated and stimulated cells from cervical tissue to identify and characterize cytokine-producing cells. Results Upon stimulation of CD3+ CD4+ endocervical cells, 1.6, 3.4, and 1.5% were induced to produce IL-22, IL-17, and both cytokines, respectively. Stimulation of CD3+ CD4+ ectocervical cells resulted in 3.3% IL-22+, 5.5% IL-17+ and 2.6% IL-22+ IL17+ cells. CD45+ CD3- cells had relatively high endogenous levels of cytokine expression that did not increase upon stimulation. Innate lymphoid cells (ILCs) made up 5.7-8% of CD45+ cervical cells and stimulation caused increases in IL-17 and IL-22. Conclusion These studies show that the majority of the CD45+ leukocytes that can be induced to produce IL-22 and IL-17 in cervix are CD3+ CD4+, but ILCs are also present and can make both cytokines. [ABSTRACT FROM AUTHOR]

Innate lymphoid cells (ILCs) are important subsets of innate immune cells that regulate mucosal immunity. ILCs include natural killer cells, innate lymphoid cells-1 (ILC1s), ILC2s, and ILC3s, which have extremely important roles in the immune system. In this review, we summarize the regulation of mRNA stability mediated through various factors in ILCs (e.g., cytokines, RNA-binding proteins, non-coding RNAs) and their roles in mediating functions in different ILC subsets. In addition, we discuss potential therapeutic targets for diseases such as chronic obstructive pulmonary disease, cancer, and pulmonary fibrosis by regulation of mRNA stability in ILCs, which may provide novel directions for future clinical research., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Deng, Shi, Luo, Zhang, Dong, Wang, Zhou, Wei, Li, Xu, Xu, Sun, Ni, Wu, Yang, Han and Tian.)

Innate lymphoid cells (ILCs) are identified as novel population of hematopoietic cells which protect the body by coordinating the innate immune response against a wide range of threats including infections, tissue damages and homeostatic disturbances. ILCs, particularly ILC2 cells, are found throughout the body including the brain. ILCs are morphologically similar to lymphocytes, express and release high levels of T-helper (Th)1, Th2 and Th17 cytokines but do not express classical cell-surface markers that are associated with other immune cell lineages. Three types of ILCs (ILC1, 2 & 3) have been reported depending upon the cytokines produced. ILC1 cells encompass natural killer (NK) cells and interferon (IFN)-g releasing cells; ILC2 cells release the Th2 cytokines, IL-5, IL-9 and IL-13 in response to IL-25 and IL-33; and ILC3 cells which release IL-17 and IL-22. ILC2 cells have been implicated inmucosal reactions occurring in animal models of allergic asthma and virus-induced lung disorders resulting in the regulation of airway remodeling and tissue homeostasis. There is evidence for increased ILC2 cell numbers in allergic responses in man but little is known about the role of ILCs in chronic obstructive pulmonary disease (COPD). Further understanding of the characteristics of ILCs such as their origin, location and phenotypes and function would help to clarify the role of these cells in the pathogenesis of various lung diseases. In this review we will focus on the role of ILC2 cells and consider their origin, function,location and possible role in the pathogenesis of the chronic inflammatory disorders such as asthma and COPD. [ABSTRACT FROM AUTHOR]

The discovery of the specification of CD4+ helper T cells to discrete effector 'lineages' represented a watershed event in conceptualizing mechanisms of host defense and immunoregulation. However, our appreciation for the actual complexity of helper T-cell subsets continues unabated. Just as the Sami language of Scandinavia has 1000 different words for reindeer, immunologists recognize the range of fates available for a CD4+ T cell is numerous and may be underestimated. Added to the crowded scene for helper T-cell subsets is the continuously growing family of innate lymphoid cells ( ILCs), endowed with common effector responses and the previously defined 'master regulators' for CD4+ helper T-cell subsets are also shared by ILC subsets. Within the context of this extraordinary complexity are concomitant advances in the understanding of transcriptomes and epigenomes. So what do terms like 'lineage commitment' and helper T-cell 'specification' mean in the early 21st century? How do we put all of this together in a coherent conceptual framework? It would be arrogant to assume that we have a sophisticated enough understanding to seriously answer these questions. Instead, we review the current status of the flexibility of helper T-cell responses in relation to their genetic regulatory networks and epigenetic landscapes. Recent data have provided major surprises as to what master regulators can or cannot do, how they interact with other transcription factors and impact global genome-wide changes, and how all these factors come together to influence helper cell function. [ABSTRACT FROM AUTHOR]

Inflammation is a very complex immunopathological process occurring due to exaggerated activation of immune system in response to various inflammatory stimuli (i.e. bacterial, viral, fungal or parasitic antigens, xenobiotics, autoantigens and sterile inflammation of unknown cause (i.e. tumor associated inflammation), traumatic inflammation or allergic inflammation etc.). Innate lymphoid cells (ILCs) are particular newly discovered immune cells, which have characteristics of both innate and adaptive immune cells. These cells have shown very significant roles in the pathogenesis of inflammatory disorders at mucosal surfaces (i.e. respiratory tract, gastrointestinal tract and mucosal skin surfaces or barriers). The present review, explores their role in pathogenesis of inflammation at mucosal sites. [ABSTRACT FROM AUTHOR]

Highlights: [•] Immune system major player of inflammation. [•] Innate lymphoid cells newly identified class of immune cells. [•] Innate lymphoid cell in pathogenesis of inflammation. [•] Modulation of ILCs to control inflammation. [Copyright &y& Elsevier]

Elabela is a component of the apelinergic system and may exert a cardioprotective role by regulating the innate immune responses. Innate lymphoid cells (ILCs) have a significant role in initiating and progressing immune-inflammatory responses. While ILCs have been intensively investigated during the last decade, little is known about their relationship with the apelinergic system and their cardiac diversity in a gender-based paradigm. In this study, we investigated the polarization of cardiac ILCs by Elabela in males versus females in a mouse model. Using flow cytometry and immunohistochemistry analyses, we showed a potential interplay between Elabela and cardiac ILCs and whether such interactions depend on sexual dimorphism. Our findings showed, for the first time, that Elabela is expressed by cardiac ILCs, and its expression is higher in females' ILC class 3 (ILC3s) compared to males. Females had higher frequencies of ILC1s, and Elabela was able to suppress T-cell activation and the expression of co-stimulatory CD28 in a mixed lymphocyte reaction assay (MLR). In conclusion, our results suggest, for the first time, a protective role for Elabela through its interplay with ILCs and that it can be used as an immunotherapeutic target in the treatment of cardiovascular disorders in a gender-based fashion.

Celiac disease (CD) is a multisystem disease in which different organs may be affected. We investigate whether circulating innate lymphoid cells (ILCs) contribute to the CD peripheral inflammatory status. We find that the CD cytokine profile is characterized by high concentrations of IL-12p40, IL-18, and IFN-γ, paralleled by an expansion of ILC precursors (ILCPs). In the presence of the gliadin peptides p31–43 and pα-9, ILCPs from CD patients increase transglutaminase 2 (TG2) expression, produce IL-18 and IFN-γ, and stimulate CD4+ T lymphocytes. IFN-γ is also produced upon stimulation with IL-12p40 and IL-18 and is inhibited by the addition of vitamin D. Low levels of blood vitamin D correlate with high IFN-γ and ILCP presence and mark the CD population mostly affected by extraintestinal symptoms. Dietary vitamin D supplementation appears to be an interesting therapeutic approach to dampen ILCP-mediated IFN-γ production. [Display omitted] • ILCPs are enriched in the peripheral blood of celiac patients • ILCPs react to gliadin peptides by producing cytokines and stimulating T cells • ILCP production of IFN-γ can be inhibited by vitamin D • High IFN-γ and low vitamin D correlate with more extraintestinal symptoms Ercolano et al. illustrate how gliadin peptide-driven ILCP activation contributes to the peripheral, extraintestinal inflammation characterizing celiac patients. ILCP activation is dampened by vitamin D, which is low in patients experiencing severe systemic inflammation and showing more extraintestinal symptoms. [ABSTRACT FROM AUTHOR]