Showing papers in "Seminars in Immunopathology in 2019"
TL;DR: The roles of proinflammatory cytokines and environmental stimuli in the control of Th17 differentiation and chronic tissue inflammation by pathogenic Th17 cells in humans and in mouse models of autoimmune diseases are discussed.
Abstract: IL-17-producing T helper (Th17) cells have been implicated in the pathogenesis of many inflammatory and autoimmune diseases. Targeting the effector cytokines IL-17 and GM-CSF secreted by autoimmune Th17 cells has been shown to be effective for the treatment of the diseases. Understanding a molecular basis of Th17 differentiation and effector functions is therefore critical for the regulation of the pathogenicity of tissue Th17 cells in chronic inflammation. Here, we discuss the roles of proinflammatory cytokines and environmental stimuli in the control of Th17 differentiation and chronic tissue inflammation by pathogenic Th17 cells in humans and in mouse models of autoimmune diseases. We also highlight recent advances in the regulation of pathogenic Th17 cells by gut microbiota and immunometabolism in autoimmune arthritis.
241 citations
TL;DR: The importance of sex-dependent differences in vaccine-induced immunity is highlighted and the role of sex as a modulator of humoral immunity, key to long-term pathogen-specific protection is addressed.
Abstract: Vaccines are among the most impactful public health interventions, preventing millions of new infections and deaths annually worldwide. However, emerging data suggest that vaccines may not protect all populations equally. Specifically, studies analyzing variation in vaccine-induced immunity have pointed to the critical impact of genetics, the environment, nutrition, the microbiome, and sex in influencing vaccine responsiveness. The significant contribution of sex to modulating vaccine-induced immunity has gained attention over the last years. Specifically, females typically develop higher antibody responses and experience more adverse events following vaccination than males. This enhanced immune reactogenicity among females is thought to render females more resistant to infectious diseases, but conversely also contribute to higher incidence of autoimmunity among women. Dissection of mechanisms which underlie sex differences in vaccine-induced immunity has implicated hormonal, genetic, and microbiota differences across males and females. This review will highlight the importance of sex-dependent differences in vaccine-induced immunity and specifically will address the role of sex as a modulator of humoral immunity, key to long-term pathogen-specific protection.
238 citations
TL;DR: Results from ECHO-301, the first large phase 3 trial to evaluate an IDO1-selective enzyme inhibitor (epacadostat) in combination with an anti-PD1 antibody (pembrolizumab) in advanced melanoma, showed no indication that epacADostat provided an increased benefit.
Abstract: With immunotherapy enjoying a rapid resurgence based on the achievement of durable remissions in some patients with agents that derepress immune function, commonly referred to as "checkpoint inhibitors," enormous attention developed around the IDO1 enzyme as a metabolic mediator of immune escape in cancer. In particular, outcomes of multiple phase 1/2 trials encouraged the idea that small molecule inhibitors of IDO1 may improve patient responses to anti-PD1 immune checkpoint therapy. However, recent results from ECHO-301, the first large phase 3 trial to evaluate an IDO1-selective enzyme inhibitor (epacadostat) in combination with an anti-PD1 antibody (pembrolizumab) in advanced melanoma, showed no indication that epacadostat provided an increased benefit. Here we discuss several caveats associated with this failed trial. First is the uncertainty as to whether the target was adequately inhibited. In particular, there remains a lack of direct evidence regarding the degree of IDO1 inhibition within the tumor, and previous trial data suggest that sufficient drug exposure may not have been achieved at the dose tested in ECHO-301. Second, while there is a mechanistic rationale for the combination tested, the preclinical data were not particularly compelling. More efficacious combinations have been demonstrated with DNA damaging modalities which may therefore be a more attractive alternative. Third, as a highly selective IDO1 inhibitor, epacadostat was advanced aggressively despite preclinical genetic evidence of tumors bypassing IDO1 blockade. Indeed, a well-grounded literature starting in 2011 points to targeting strategies that account for both IDO and tryptophan 2,3-dioxygenase as more appealing directions to pursue, including dual inhibitors and inhibitors of nodal downstream effector pathways such as aryl hydrocarbon receptor blockade. Overall, the clinical readout from a single trial with significant limitations is by no means a definitive test for the field. While biomarker information yet to be gleaned from ECHO-301 may yet reveal useful information regarding IDO1 pathway drugs, better rationalized compounds and better rationalized trial designs will be important in the future to accurately gauge medical impact.
172 citations
TL;DR: T cell exhaustion is often associated with inefficient control of persisting infections and cancers, but re-invigoration of exhausted T cells with inhibitory receptor blockade can promote improved immunity and disease outcome.
Abstract: CD8+ T cells are important for the protective immunity against intracellular pathogens and tumor. In the case of chronic infection or cancer, CD8+ T cells are exposed to persistent antigen and/or inflammatory signals. This excessive amount of signals often leads CD8+ T cells to gradual deterioration of T cell function, a state called "exhaustion." Exhausted T cells are characterized by progressive loss of effector functions (cytokine production and killing function), expression of multiple inhibitory receptors (such as PD-1 and LAG3), dysregulated metabolism, poor memory recall response, and homeostatic proliferation. These altered functions are closely related with altered transcriptional program and epigenetic landscape that clearly distinguish exhausted T cells from normal effector and memory T cells. T cell exhaustion is often associated with inefficient control of persisting infections and cancers, but re-invigoration of exhausted T cells with inhibitory receptor blockade can promote improved immunity and disease outcome. Accumulating evidences support the therapeutic potential of targeting exhausted T cells. However, exhausted T cells comprise heterogenous cell population with distinct responsiveness to intervention. Understanding molecular mechanism of T cell exhaustion is essential to establish rational immunotherapeutic interventions.
145 citations
TL;DR: The evidence for the microgenderome is reviewed and the role it plays in driving sex differences in immunity and disease susceptibility is contemplated, as well as the impact that biological sex might play in the response to treatments aimed at manipulating the GIT microbiota, such as prebiotics, live biotherapeutics, and faecal microbial transplant.
Abstract: Sex differences in immunity are well described in the literature and thought to be mainly driven by sex hormones and sex-linked immune response genes. The gastrointestinal tract (GIT) is one of the largest immune organs in the body and contains multiple immune cells in the GIT-associated lymphoid tissue, Peyer's patches and elsewhere, which together have profound effects on local and systemic inflammation. The GIT is colonised with microbial communities composed of bacteria, fungi and viruses, collectively known as the GIT microbiota. The GIT microbiota drives multiple interactions locally with immune cells that regulate the homeostatic environment and systemically in diverse tissues. It is becoming evident that the microbiota differs between the sexes, both in animal models and in humans, and these sex differences often lead to sex-dependent changes in local GIT inflammation, systemic immunity and susceptibility to a range of inflammatory diseases. The sexually dimorphic microbiome has been termed the 'microgenderome'. Herein, we review the evidence for the microgenderome and contemplate the role it plays in driving sex differences in immunity and disease susceptibility. We further consider the impact that biological sex might play in the response to treatments aimed at manipulating the GIT microbiota, such as prebiotics, live biotherapeutics, (probiotics, synbiotics and bacteriotherapies) and faecal microbial transplant. These alternative therapies hold potential in the treatment of both psychological (e.g., anxiety, depression) and physiological (e.g., irritable bowel disease) disorders differentially affecting males and females.
144 citations
TL;DR: In this review, the principles of adoptively transferred T cells for the treatment of cancer are briefly outlined.
Abstract: Adoptive cell therapy (ACT) utilizing either tumor-infiltrating lymphocyte (TIL)-derived T cells or T cells genetically engineered to express tumor recognizing receptors has emerged as a powerful and potentially curative therapy for several cancers Many ACT-based therapies have recently entered late-phase clinical testing, with several T cell therapies already achieving regulatory approval for the treatment of patients with B cell malignancies In this review, we briefly outline the principles of adoptively transferred T cells for the treatment of cancer
127 citations
TL;DR: An overview on the features of islet inflammation in diabetes and models of prediabetes is provided and the recently emerging physiologic signaling role of cytokines during adaptation and normal function of islets is discussed.
Abstract: Metabolic diseases including type 2 diabetes are associated with meta-inflammation. β-Cell failure is a major component of the pathogenesis of type 2 diabetes. It is now well established that increased numbers of innate immune cells, cytokines, and chemokines have detrimental effects on islets in these chronic conditions. Recently, evidence emerged which points to initially adaptive and restorative functions of inflammatory factors and immune cells in metabolism. In the following review, we provide an overview on the features of islet inflammation in diabetes and models of prediabetes. We separately emphasize what is known on islet inflammation in humans and focus on in vivo animal models and how they are used to elucidate mechanistic aspects of islet inflammation. Further, we discuss the recently emerging physiologic signaling role of cytokines during adaptation and normal function of islet cells.
111 citations
TL;DR: How the increasing knowledge of the T cell biology has been comprehensively translated into the pathogenetic understanding of respective model skin diseases and, based thereon, has revolutionized their daily clinical management is shown.
Abstract: Forming the outer body barrier, our skin is permanently exposed to pathogens and environmental hazards. Therefore, skin diseases are among the most common disorders. In many of them, the immune system plays a crucial pathogenetic role. For didactic and therapeutic reasons, classification of such immune-mediated skin diseases according to the underlying dominant immune mechanism rather than to their clinical manifestation appears to be reasonable. Immune-mediated skin diseases may be mediated mainly by T cells, by the humoral immune system, or by uncontrolled unspecific inflammation. According to the involved T cell subpopulation, T cell–mediated diseases may be further subdivided into T1 cell–dominated (e.g., vitiligo), T2 cell–dominated (e.g., acute atopic dermatitis), T17/T22 cell–dominated (e.g., psoriasis), and Treg cell–dominated (e.g., melanoma) responses. Moreover, T cell–dependent and -independent responses may occur simultaneously in selected diseases (e.g., hidradenitis suppurativa). The effector mechanisms of the respective T cell subpopulations determine the molecular changes in the local tissue cells, leading to specific microscopic and macroscopic skin alterations. In this article, we show how the increasing knowledge of the T cell biology has been comprehensively translated into the pathogenetic understanding of respective model skin diseases and, based thereon, has revolutionized their daily clinical management.
91 citations
TL;DR: A roadmap for development of off-the-shelf cell therapy based on natural killer cells derived from induced pluripotent stem cells (iPSCs) is outlined and strategies to engineer iPSC-derived NK (i PSC-NK) cells for enhanced functional potential, persistence, and homing are discussed.
Abstract: Cell therapy is emerging as a very promising therapeutic modality against cancer, spearheaded by the clinical success of chimeric antigen receptor (CAR) modified T cells for B cell malignancies. Currently, FDA-approved CAR-T cell products are based on engineering of autologous T cells harvested from the patient, typically using a central manufacturing facility for gene editing before the product can be delivered to the clinic and infused to the patients. For a broader implementation of advanced cell therapy and to reduce costs, it would be advantageous to use allogeneic "universal" cell therapy products that can be stored in cell banks and provided upon request, in a manner analogous to biopharmaceutical drug products. In this review, we outline a roadmap for development of off-the-shelf cell therapy based on natural killer (NK) cells derived from induced pluripotent stem cells (iPSCs). We discuss strategies to engineer iPSC-derived NK (iPSC-NK) cells for enhanced functional potential, persistence, and homing.
89 citations
TL;DR: Recent evidence demonstrating that TLR7 escapes from X chromosome inactivation in pDCs, monocytes, and B lymphocytes from women and Klinefelter syndrome men is reviewed, connecting the presence of two X chromosomes with the enhanced immunity of women and their increased susceptibility toTLR7-dependent autoimmune syndromes.
Abstract: Women develop stronger immune responses than men, with positive effects on the resistance to viral or bacterial infections but magnifying also the susceptibility to autoimmune diseases like systemic lupus erythematosus (SLE). In SLE, the dosage of the endosomal Toll-like receptor 7 (TLR7) is crucial. Murine models have shown that TLR7 overexpression suffices to induce spontaneous lupus-like disease. Conversely, suppressing TLR7 in lupus-prone mice abolishes SLE development. TLR7 is encoded by a gene on the X chromosome gene, denoted TLR7 in humans and Tlr7 in the mouse, and expressed in plasmacytoid dendritic cells (pDC), monocytes/macrophages, and B cells. The receptor recognizes single-stranded RNA, and its engagement promotes B cell maturation and the production of pro-inflammatory cytokines and antibodies. In female mammals, each cell randomly inactivates one of its two X chromosomes to equalize gene dosage with XY males. However, 15 to 23% of X-linked human genes escape X chromosome inactivation so that both alleles can be expressed simultaneously. It has been hypothesized that biallelic expression of X-linked genes could occur in female immune cells, hence fostering harmful autoreactive and inflammatory responses. We review here the current knowledge of the role of TLR7 in SLE, and recent evidence demonstrating that TLR7 escapes from X chromosome inactivation in pDCs, monocytes, and B lymphocytes from women and Klinefelter syndrome men. Female B cells where TLR7 is thus biallelically expressed display higher TLR7-driven functional responses, connecting the presence of two X chromosomes with the enhanced immunity of women and their increased susceptibility to TLR7-dependent autoimmune syndromes.
87 citations
TL;DR: The traditional view that Treg cells become necessarily pathogenic by gaining effector functions was challenged by recent findings and supports the notion of Treg cell lineage plasticity.
Abstract: Regulatory (Treg) cells are key regulators of inflammation and important for immune tolerance and homeostasis. A major progress has been made in the identification and classification of Treg cells. Due to technological advances, we have gained deep insights in the epigenetic regulation of Treg cells. The use of fate reporter mice allowed addressing the functional consequences of loss of Foxp3 expression. Depending on the environment Treg cells gain effector functions upon loss of Foxp3 expression. However, the traditional view that Treg cells become necessarily pathogenic by gaining effector functions was challenged by recent findings and supports the notion of Treg cell lineage plasticity. Treg cell stability is also a major issue for Treg cell therapies. Clinical trials are designed to use polyclonal Treg cells as therapeutic tools. Here, we summarize the role of Treg cells in selected autoimmune diseases and recent advances in the field of Treg targeted therapies.
TL;DR: This review summarizes the current knowledge of the biological processes providing an inflammatory basis for DR and DME and emerging therapeutic approaches targeting inflammation are discussed, including blockade of angiopoietin 2 and other molecular targets such as interleukin (IL)-6, IL-1β, plasma kallikrein, and integrins.
Abstract: Mounting evidence suggests that immunological mechanisms play a fundamental role in the pathogenesis of diabetic retinopathy (DR) and diabetic macular edema (DME). Upregulation of cytokines and other proinflammatory mediators leading to persistent low-grade inflammation is believed to actively contribute to the DR-associated damage to the retinal vasculature, inducing breakdown of the blood-retinal barrier, subsequent macular edema formation, and promotion of retinal neovascularization. This review summarizes the current knowledge of the biological processes providing an inflammatory basis for DR and DME. In addition, emerging therapeutic approaches targeting inflammation are discussed, including blockade of angiopoietin 2 and other molecular targets such as interleukin (IL)-6, IL-1β, plasma kallikrein, and integrins.
TL;DR: Tuberculosis rates are significantly higher in men than in women, reflected by a male-to-female ratio for worldwide case notifications of 1.7.
Abstract: Tuberculosis is the most prevalent bacterial infectious disease in humans and the leading cause of death from a single infectious agent, ranking above HIV/AIDS. The causative agent, Mycobacterium tuberculosis, is carried by an estimated two billion people globally and claims more than 1.5 million lives each year. Tuberculosis rates are significantly higher in men than in women, reflected by a male-to-female ratio for worldwide case notifications of 1.7. This phenomenon is not new and has been reported in various countries and settings over the last century. However, the reasons for the observed gender bias are not clear, potentially highly complex and discussed controversially in the literature. Both gender- (referring to sociocultural roles and behavior) and sex-related factors (referring to biological aspects) likely contribute to higher tuberculosis rates in men and will be discussed.
TL;DR: It is argued that studies taking sex differences into account could pave the way for sex-specific and therefore personalized treatment in autoimmune CNS disorders, due to a lack of systematic studies on treatment responses in males versus females.
Abstract: Stronger adaptive immune responses in females can be observed in different mammals, resulting in better control of infections compared to males. However, this presumably evolutionary difference likely also drives higher incidence of autoimmune diseases observed in humans. Here, we summarize sex differences in the most common autoimmune diseases of the central nervous system (CNS) and discuss recent advances in the understanding of possible underlying immunological and CNS intrinsic mechanisms. In multiple sclerosis (MS), the most common inflammatory disease of the CNS, but also in rarer conditions, such as neuromyelitis optica spectrum disorders (NMOSD) or neuronal autoantibody-mediated autoimmune encephalitis (AE), sex is one of the top risk factors, with women being more often affected than men. Immunological mechanisms driving the sex bias in autoimmune CNS diseases are complex and include hormonal as well as genetic and epigenetic effects, which could also be exerted indirectly via modulation of the microbiome. Furthermore, CNS intrinsic differences could underlie the sex bias in autoimmunity by differential responses to injury. The strong effects of sex on incidence and possibly also activity and progression of autoimmune CNS disorders suggest that treatments need to be tailored to each sex to optimize efficacy. To date, however, due to a lack of systematic studies on treatment responses in males versus females, evidence in this area is still sparse. We argue that studies taking sex differences into account could pave the way for sex-specific and therefore personalized treatment.
TL;DR: Promoting anti-atherogenic signalling through the stimulation of endogenous resolution of inflammation pathways may provide a novel therapeutic strategy in cardiovascular prevention.
Abstract: Omega-3 fatty acids serve as the substrate for the formation of a group of lipid mediators that mediate the resolution of inflammation. The cardiovascular inflammatory response in atherosclerosis and vascular injury is characterized by a failure in the resolution of inflammation, resulting in a chronic inflammatory response. The proresolving lipid mediator resolvin E1 (RvE1) is formed by enzymatic conversion of the omega-3 fatty acid eicosapentaenoic acid (EPA), and signals resolution of inflammation through its receptor ChemR23. Importantly, the resolution of cardiovascular inflammation is an active, multifactorial process that involves modulation of the immune response, direct actions on the vascular wall, as well as close interactions between macrophages and vascular smooth muscle cells. Promoting anti-atherogenic signalling through the stimulation of endogenous resolution of inflammation pathways may provide a novel therapeutic strategy in cardiovascular prevention.
TL;DR: It is clear that a deeper understanding of metabolic regulation in osteoclasts will offer broader translational potential for the treatment of human bone disorders because targeting the pathways associated with metabolic reprogramming has shown beneficial effects on pathological conditions.
Abstract: Osteoclasts are bone-resorbing cells that play an essential role in the remodeling of the bone. Defects in osteoclasts thus result in unbalanced bone remodeling, leading to numerous pathological conditions such as osteoporosis, bone metastasis, and inflammatory bone erosion. Metabolism is any process a cell utilizes to meet its energetic demand for biological functions. Along with signaling pathways and osteoclast-specific gene expression programs, osteoclast differentiation activates metabolic programs. The energy generated from metabolic reprogramming in osteoclasts not only supports the phenotypic changes from mononuclear precursor cells to multinuclear osteoclasts, but also facilitates bone resorption, a major function of terminally differentiated, mature osteoclasts. While oxidative phosphorylation is studied as a major metabolic pathway that fulfills the energy demands of osteoclasts, all metabolic pathways are closely interconnected. Therefore, it remains important to understand the various aspects of osteoclast metabolism, including the roles and effects of glycolysis, glutaminolysis, fatty acid synthesis, and fatty acid oxidation. Targeting the pathways associated with metabolic reprogramming has shown beneficial effects on pathological conditions. As a result, it is clear that a deeper understanding of metabolic regulation in osteoclasts will offer broader translational potential for the treatment of human bone disorders.
TL;DR: In patients with advanced and transforming disease towards leukemic transformation or having transformed to acute myeloid leukemia, “triple therapy” is proposed as a novel treatment modality to be tested in clinical trials combining IFN-alpha2, DNA-hypomethylator, and ruxolitinib.
Abstract: The first clinical trials of the safety and efficacy of interferon-alpha2 (IFN-alpha2) were performed about 30 years ago. Since then, several single-arm studies have convincingly demonstrated that IFN-alpha2 is a highly potent anti-cancer agent in several cancer types but unfortunately not being explored sufficiently due to a high toxicity profile when using non-pegylated IFN-alpha2 or high dosages or due to competitive drugs, that for clinicians at first glance might look more attractive. Within the hematological malignancies, IFN-alpha2 has only recently been revived in patients with the Philadelphia-negative myeloproliferative neoplasms—essential thrombocytosis, polycythemia vera, and myelofibrosis (MPNs)—and in patients with chronic myelogenous leukemia (CML) in combination with tyrosine kinase inhibitors. In this review, we tell the IFN story in MPNs from the very beginning in the 1980s up to 2018 and describe the perspectives for IFN-alpha2 treatment of MPNs in the future. The mechanisms of actions are discussed and the impact of chronic inflammation as the driving force for clonal expansion and disease progression in MPNs is discussed in the context of combination therapies with potent anti-inflammatory agents, such as the JAK1–2 inhibitors (licensed only ruxolitinib) and statins as well. Interferon-alpha2 being the cornerstone treatment in MPNs and having the potential of inducing minimal residual disease (MRD) with normalization of the bone marrow and low-JAK2V617F allele burden, we believe that combination therapy with ruxolitinib may be even more efficacious and hopefully revert disease progression in many more patients to enter the path towards MRD. In patients with advanced and transforming disease towards leukemic transformation or having transformed to acute myeloid leukemia, “triple therapy” is proposed as a novel treatment modality to be tested in clinical trials combining IFN-alpha2, DNA-hypomethylator, and ruxolitinib. The rationale for this “triple therapy” is given, including the fact that even in AML, IFN-alpha2 as monotherapy may revert disease progression. We envisage a new and bright future with many more patients with MPNs obtaining MRD on the above therapies. From this stage—and even before—vaccination strategies may open a new horizon with cure being the goal for some patients.
TL;DR: This review will discuss the active role of regulatory immune cells in inflammation resolution as well as the role of tissue and non-hematopoietic cells as contributors to inflammation resolution, and explore how DMTs impact the resolution of inflammation during MS.
Abstract: Multiple sclerosis (MS) is a frequent autoimmune demyelinating disease of the central nervous system (CNS). There are three clinical forms described: relapsing-remitting multiple sclerosis (RRMS), the most common initial presentation (85%) among which, if not treated, about half will transform, into the secondary progressive multiple sclerosis (SPMS) and the primary progressive MS (PPMS) (15%) that is directly progressive without superimposed clinical relapses. Inflammation is present in all subsets of MS. The relapsing/remitting form could represent itself a particular interest for the study of inflammation resolution even though it remains incomplete in MS. Successful resolution of acute inflammation is a highly regulated process and dependent on mechanisms engaged early in the inflammatory response that are scarcely studied in MS. Moreover, recent classes of disease-modifying treatment (DMTs) that are effective against RRMS act by re-establishing the inflammatory imbalance, taking advantage of the pre-existing endogenous suppressor. In this review, we will discuss the active role of regulatory immune cells in inflammation resolution as well as the role of tissue and non-hematopoietic cells as contributors to inflammation resolution. Finally, we will explore how DMTs, more specifically induction therapies, impact the resolution of inflammation during MS.
TL;DR: Encouragingly, but only anecdotally, accumulated clinical experience suggests that advanced age does not result in poorer responses or greater toxicity in elderly patients treated with anti-CTLA-4 or anti-PD-1/PD-L1 antibodies.
Abstract: Geriatric oncology, important for the ever-increasing numbers of elderly cancer patients, has thus far focused primarily on tolerance to chemotherapy. With the advent of breakthrough immunomodulatory antibody treatments relying on the patient's own immune system to control the tumor, the issue of immunosenescence becomes extremely important. There is increasingly a valid concern that anti-cancer immunity may be compromised in the elderly due to (i) their low amounts of naive T cells (potentially leading to holes in the repertoire for neoantigens), (ii) "exhaustion" of potentially tumor-specific memory T cells, and (iii) higher amounts of suppressive cells. Encouragingly, but only anecdotally, accumulated clinical experience suggests that advanced age does not result in poorer responses or greater toxicity in elderly patients treated with anti-CTLA-4 or anti-PD-1/PD-L1 antibodies. Here, I briefly contrast immune features of the elderly with the young, commonly referred to as "immunosenescence," and the influence of patient age on the outcome of checkpoint blockade. As newer agents are licensed, and new combinations tested, broader and more detailed studies focusing on the age question will be crucial and should be taken into consideration when designing clinical trials.
TL;DR: A brief overview of the pro- and anti-inflammatory aspects of IL-6 is given and an update on its role in metabolic regulation is provided, with a specific focus on glucose homeostasis and adipose tissue metabolism.
Abstract: Low-grade inflammation is recognized as an important factor in the development and progression of a multitude of diseases including type 2 diabetes mellitus and cardiovascular disease. The potential of using antibody-based therapies that neutralize key players of low-grade inflammation has gained scientific momentum as a novel therapeutic strategy in metabolic diseases. As interleukin-6 (IL-6) is traditionally considered a key pro-inflammatory factor, the potential of expanding the use of anti-IL-6 therapies to metabolic diseases is intriguing. However, IL-6 is a molecule of a very pleiotropic nature that regulates many aspects of not only inflammation but also metabolism. In this review, we give a brief overview of the pro- and anti-inflammatory aspects of IL-6 and provide an update on its role in metabolic regulation, with a specific focus on glucose homeostasis and adipose tissue metabolism. Finally, we shall discuss the metabolic implications and clinical potential of blocking IL-6 signaling, focusing on glucose homeostasis and lipid metabolism.
TL;DR: Greater consideration of the combined effects of sex and age as biological variables in epidemiological, clinical, and animal studies of influenza pathogenesis is needed.
Abstract: Males and females differ in the outcome of influenza A virus (IAV) infections, which depends significantly on age. During a typical seasonal influenza epidemic, young children (< 10 years of age) and aged adults (65+ years of age) are at greatest risk for severe disease, and among these age groups, males tend to suffer a worse outcome from IAV infection than females. Following infection with either pandemic or outbreak strains of IAVs, females of reproductive ages (i.e., 15–49 years of age) experience a worse outcome than their male counterparts. Among females of reproductive ages, pregnancy is one factor linked to an increased risk of severe outcome of influenza, although it is not the sole factor explaining the female-preponderance of severe disease. Small animal models of influenza virus infection illustrate that inflammatory immune responses and repair of damaged tissue following IAV infection also differ between the sexes and impact the outcome of infection. There also is growing evidence that sex steroid hormones, including estrogens, progesterone, and testosterone, directly impact immune responses during IAV infection to alter outcomes. Greater consideration of the combined effects of sex and age as biological variables in epidemiological, clinical, and animal studies of influenza pathogenesis is needed.
TL;DR: Review articles address the developmental origins of higher susceptibility to infections and immune diseases during childhood and throughout life, and discuss how these prenatal events can contribute to sex-specific differences in the functioning of the immune system.
Abstract: The immune system defends us from environmental threats, such as infections, and detects and removes abnormal cells that can potentially lead to malignancies. Optimal immunological homeostasis is achieved when the threat is removed with high efficiency and at low cost (collateral tissue damage) for the host. The nature and strength of immune responses differ between women and men, resulting in sex-specific differences in the prevalence, manifestations, and outcomes of malignancies and autoimmune and infectious diseases. While women are in general able to mount a more vigorous immune response to infections, vaccinations, and some malignancies, they also suffer more from inflammatory and autoimmune diseases. Growing data indicate that common biological pathways leading to inflammation and immune activation are involved in the pathophysiology of autoimmune and infectious diseases, and that these pathways are regulated by sex-linked factors, including sex hormones and sex-chromosome-encoded genes. A better understanding of the fundamental processes that regulate sex-specific differences in immune responses is required to optimize prevention and treatment strategies for women and men in a first step toward personalized medicine. In the current supplemental issue of Seminars in Immunopathology, review articles address our current level of understanding of these differences and identify gaps in our knowledge related to sex differences in immunity, and their consequences for a number of diseases highly relevant for human health. Increasing evidence suggests that the functioning of our immune system is already shaped by the intrauterine environment early during immune ontogeny, and that altered prenatal development can have a significant impact on the risk for infectious and autoimmune diseases later in life. Zazara et al. [1] review the developmental origins of higher susceptibility to infections and immune diseases during childhood and throughout life, and discuss how these prenatal events can contribute to sex-specific differences in the functioning of the immune system. Several genes that play a critical role in regulating immune responses in humans, including the genes encoding for FoxP3, CD40L, TLR7, TLR8, and IL2 receptor subunit gamma, are located on the X chromosome. Souyris et al. [2] review recent exciting data demonstrating that escape from X-chromosome inactivation can result in different expression levels of TLR7 between women and men, and discuss the implication of these findings for the predisposition of women to TLR7-driven autoimmune diseases, such as systemic lupus erythematosus. Continuing with the theme of autoimmune diseases, Schwinge et al. [3] discuss sex-specific differences in immunity that might underlie the female predominance in two autoimmune liver diseases: autoimmune hepatitis and primary biliary cholangitis. Gold et al. [4] review the immunological mechanisms that drive inflammatory diseases of the central nervous system, including multiple sclerosis, neuromyelitis optical spectrum disorders, and neuronal autoantibody-mediated autoimmune encephalitis, all of which occur more frequently in women compared to men. While most autoimmune diseases are more frequent in women, sex differences in the incidence and clinical manifestations of infectious diseases show a more heterogeneous picture. Vom Steeg et al. [5] review differences between women and men in the outcome of influenza Avirus infections, which depend significantly on the age of the host and the causing viral strain. The authors discuss growing evidence that sex steroid hormones can directly impact immune responses during influenza A virus infection, resulting in sex-specific differences in disease manifestations and outcome. Another viral infection that shows significant differences in disease This article is a contribution to the special issue on Sex differences in immunity Guest Editors: Hanna Lotter and Marcus Altfeld
TL;DR: In this article, the authors highlight aspects that facilitate the resolution of CNS inflammation, promote tissue repair, and functional recovery after acute injury and infection that could potentially contribute as therapeutic interventions.
Abstract: The central nervous system (CNS) is comprised by an elaborate neural network that is under constant surveillance by tissue-intrinsic factors for maintenance of its homeostasis. Invading pathogens or sterile injuries might compromise vitally the CNS integrity and function. A prompt anti-inflammatory response is therefore essential to contain and repair the local tissue damage. Although the origin of the insults might be different, the principles of tissue backlashes, however, share striking similarities. CNS-resident cells, such as microglia and astrocytes, together with peripheral immune cells orchestrate an array of events that aim to functional restoration. If the acute inflammatory event remains unresolved, it becomes toxic leading to progressive CNS degeneration. Therefore, the cellular, molecular, and biochemical processes that regulate inflammation need to be on a fine balance with the intrinsic CNS repair mechanisms that influence tissue healing. The purpose of this review is to highlight aspects that facilitate the resolution of CNS inflammation, promote tissue repair, and functional recovery after acute injury and infection that could potentially contribute as therapeutic interventions.
TL;DR: The identification of neoepitopes against which the immune system is less tolerated is giving rise to a new enthusiasm by the first clinical results of the vaccine including these neoepITopes in humans, and the ability of anti-cancer vaccines to induce a population ofAnti-tumor T cells called memory resident T cells that play an important role in immunosurveillance is also a new criterion to consider in the design of therapeutic vaccines.
Abstract: Anti-cancer vaccines have raised many hopes from the start of immunotherapy but have not yet been clinically successful The few positive results of anti-cancer vaccines have been observed in clinical situations of low tumor burden or preneoplastic lesions Several new concepts and new results reposition this therapeutic approach in the field of immunotherapy Indeed, cancers that respond to anti-PD-1/PD-L1 (20-30%) are those that are infiltrated by anti-tumor T cells with an inflammatory infiltrate However, 70% of cancers do not appear to have an anti-tumor immune reaction in the tumor microenvironment To induce this anti-tumor immunity, therapeutic combinations between vaccines and anti-PD-1/PD-L1 are being evaluated In addition, the identification of neoepitopes against which the immune system is less tolerated is giving rise to a new enthusiasm by the first clinical results of the vaccine including these neoepitopes in humans The ability of anti-cancer vaccines to induce a population of anti-tumor T cells called memory resident T cells that play an important role in immunosurveillance is also a new criterion to consider in the design of therapeutic vaccines
TL;DR: The potential importance of combining PD-1 checkpoint inhibitors with a broad range of clinically active partners is highlighted, with both standard of care chemotherapy and anti-angiogenesis combinations show promising clinical activity above that predicted by the independent contributions of the agents tested on their own.
Abstract: More than 3000 clinical trials are evaluating the clinical activity of the PD-1 checkpoint inhibitors as monotherapies and in combinations with other cancer therapies [1]. The PD-1 checkpoint inhibitors are remarkable for their clinical activities in shrinking tumors across a wide range of tumor types, in causing durable responses, and in their tolerability. These attributes position them as favorable agents in clinical combinations. Historically, approaches to cancer therapy combinations focused on agents with orthogonal activities to avoid shared resistance mechanisms and shared toxicities. Although CTLA-4/PD-1 combinations have progressed based on possible immune interactions, additional approaches have used more orthogonal treatments such as standard of care chemotherapies and anti-angiogenesis inhibitors. Using the concept of independent activity pioneered by Bliss [2], examples of these approaches were compared. Both standard of care chemotherapy and anti-angiogenesis combinations show promising clinical activity above that predicted by the independent contributions of the agents tested on their own. In contrast, the combinations of CTLA4/PD-1 checkpoint inhibitors in renal cancer and melanoma show no more activity than that predicted by the independent contributions of the monotherapies. This update on approaches to the development of clinical combination therapies highlights the potential importance of combining PD-1 checkpoint inhibitors with a broad range of clinically active partners.
TL;DR: Novel insights are described in each of the phases of mucosal healing starting from damaging insults to the mucosa, epithelial restitution, and its adaption to inflammation as well as lymphocyte-driven maintenance and resolution of chronic inflammation.
Abstract: Ulcerative colitis designates an idiopathic chronic inflammatory bowel disease leading to bloody diarrhea and inflammatory alterations mostly restricted to the large intestine. Many studies continue to unravel important aspects of its etiopathogenesis, and recent pharmaceutical developments broaden the arsenal of therapeutic opportunity. In this review, we delve into the cellular and molecular determinants of successful resolution of ulcerative colitis, describing novel insights in each of the phases of mucosal healing starting from damaging insults to the mucosa, epithelial restitution, and its adaption to inflammation as well as lymphocyte-driven maintenance and resolution of chronic inflammation. Additionally, molecular switches from inflammation to resolution are explored, paving the way for future avenues to resolve ulcerative colitis.
TL;DR: These molecular rheostats promote osteoclast differentiation but suppress proinflammatory macrophage activation and inflammation, by acting lineage-intrinsically, systemically or cross generation, advancing the field of osteoimmunology.
Abstract: Emerging evidence suggest that macrophage and osteoclast are two competing differentiation outcomes from myeloid progenitors. In this review, we summarize recent advances in the understanding of the molecular mechanisms controlling the polarization of macrophage and osteoclast. These include nuclear receptors/transcription factors such as peroxisome proliferator-activated receptor γ (PPARγ) and estrogen-related receptor α (ERRα), their transcription cofactor PPARγ coactivator 1-β (PGC-1β), metabolic factors such as mitochondrial complex I (CI) component NADH:ubiquinone oxidoreductase iron-sulfur protein 4 (Ndufs4), as well as transmembrane receptors such as very-low-density-lipoprotein receptor (VLDLR). These molecular rheostats promote osteoclast differentiation but suppress proinflammatory macrophage activation and inflammation, by acting lineage-intrinsically, systemically or cross generation. These findings provide new insights to the understanding of the interactions between innate immunity and bone remodeling, advancing the field of osteoimmunology.
TL;DR: The cellular and molecular “scar” and its imprints left after clinical resolution of psoriasis treated with anti-TNFα, anti- IL-17, or anti-IL-23 antibodies or phototherapy are elucidated.
Abstract: Psoriasis is a chronic inflammatory skin disease that involves numerous types of immune cells and cytokines resulting in an inflammatory feedback loop and hyperproliferation of the epidermis. A more detailed understanding of the underlying pathophysiology has revolutionized anti-psoriatic treatment and led to the development of various new drugs targeting key inflammatory cytokines such as IL-17A and IL-23. Successfully treated psoriatic lesions often resolve completely, leaving nothing visible to the naked eye. However, such lesions tend to recur within months at the exact same body sites. What is left behind at the cellular and molecular levels that potentially reinitiates psoriasis? Here, we elucidate the cellular and molecular “scar” and its imprints left after clinical resolution of psoriasis treated with anti-TNFα, anti-IL-17, or anti-IL-23 antibodies or phototherapy. Hidden cytokine stores and remaining tissue-resident memory T cells (TRMs) might hold the clue for disease recurrence.
TL;DR: A model where multi-directional crosstalk between connective tissue cells (chondrocytes, fibroblasts), innate immune cells, and sensory neurons in the affected joint may promote OA pathology and pain is proposed.
Abstract: Osteoarthritis (OA) is a chronic progressive, painful disease of synovial joints, characterized by cartilage degradation, subchondral bone remodeling, osteophyte formation, and synovitis. It is now widely appreciated that the innate immune system, and in particular Toll-like receptors (TLRs), contributes to pathological changes in OA joint tissues. Furthermore, it is now also increasingly recognized that TLR signaling plays a key role in initiating and maintaining pain. Here, we reviewed the literature of the past 5 years with a focus on how TLRs may contribute to joint damage and pain in OA. We discuss biological effects of specific damage-associated molecular patterns (DAMPs) which act as TLR ligands in vitro, including direct effects on pain-sensing neurons. We then discuss the phenotype of transgenic mice that target TLR pathways, and provide evidence for a complex balance between pro- and anti-inflammatory signaling pathways activated by OA DAMPs. Finally, we summarize clinical evidence implicating TLRs in OA pathogenesis, including polymorphisms and surrogate markers of disease activity. Our review of the literature led us to propose a model where multi-directional crosstalk between connective tissue cells (chondrocytes, fibroblasts), innate immune cells, and sensory neurons in the affected joint may promote OA pathology and pain.
TL;DR: This review aims to summarize the current knowledge regarding the role of both tumor-intrinsic and tumor-extrinsics factors in the development of resistance to cancer immunotherapy and to discuss current and possible future therapeutic strategies targeting these mechanisms.
Abstract: In recent times, advances in cancer immunotherapy have yielded impressive, durable clinical responses in patients with varied subtypes of cancer. However, a significant proportion of patients who initially demonstrate encouraging tumor regression develop resistance and progress over time. The identification of novel therapeutic approaches to overcome resistance may result in significantly improved clinical outcomes and remains an area of high scientific priority. This review aims to summarize the current knowledge regarding the role of both tumor-intrinsic and tumor-extrinsic factors in the development of resistance to cancer immunotherapy and to discuss current and possible future therapeutic strategies targeting these mechanisms.