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Infections often precede the onset of autoimmune disease and molecular (or epitope) mimicry is a plausible link. Cross-reacting epitopes are common between an infecting microorganism and the host because negative selection of self-reactive T-cells and B-cells is frequently incomplete. Complete eradication could lead to major voids in the immunologic repertoire. The association of an autoimmune disease with a microbial epitope may signify a causal relationship with the organism, an indirect connection through bystander effects, persistent infection or coincidence. There are well-established examples of a microbial mimic inducing a defined model of autoimmune disease in experimental animals but such instances are still relatively rare in humans. Establishing epitope mimicry as a direct cause opens opportunities for preventing the disease. Current approaches to cancer immunotherapy provides new examples of epitope mimicry between cancer antigens and normal tissue antigens. [ABSTRACT FROM AUTHOR]

On September 20, 2016 the American Autoimmune Related Disease Association convened a selected group of 16 experts in Washington DC to discuss current issues and future directions of research in autoimmune diseases from the cell signaling perspective. The major topics considered included new findings on the follicular T cell cells in mice, their metabolic patterns and their control by the newly discovered T follicular regulatory cells. Current work on the metabolic pathways deemed important for the function of T cells was presented. The broader implications of these studies on our understanding of human and murine T regulatory cell and current aspects of B cell biology, innate immunity and organ damage were discussed. This document should provide the reader with a quick update on these topics and help instigate novel studies. [ABSTRACT FROM AUTHOR]

Despite of a multitude of excellent studies, the regulatory role of natural killer (NK) cells in the pathogenesis of inflammatory cardiac disease is greatly underappreciated. Clinical abnormalities in the numbers and functions of NK cells are observed in myocarditis and inflammatory dilated cardiomyopathy (DCMi) as well as in cardiac transplant rejection [1–6] . Because treatment of these disorders remains largely symptomatic in nature, patients have little options for targeted therapies [7,8] . However, blockade of NK cells and their receptors can protect against inflammation and damage in animal models of cardiac injury and inflammation. In these models, NK cells suppress the maturation and trafficking of inflammatory cells, alter the local cytokine and chemokine environments, and induce apoptosis in nearby resident and hematopoietic cells [1,9,10] . This review will dissect each protective mechanism employed by NK cells and explore how their properties might be exploited for their therapeutic potential. [ABSTRACT FROM AUTHOR]

Autoimmune diseases represent a family of at least 80 illnesses that share a common pathogenesis: an immune-mediated attack on the body's own organs. Collectively, autoimmune diseases affect some 20 million Americans, predominantly women. Many of these diseases are increasing in frequency in industrialized countries. Treatment of autoimmune diseases improved greatly during the second half of the 20th century but has been hampered because the diseases often progress before a clinical diagnosis is possible. Research in the 21st century is focusing on prospective prediction using the tools of systems biology. [ABSTRACT FROM AUTHOR]

IL6 is a pleiotropic cytokine that is made in response to perturbations in homeostasis. IL6 becomes elevated in the acute response to host injury and can activate immune cells, direct immune cell trafficking, signal protective responses in local tissue, initial the acute phase response or initiate wound healing. In the short term this proinflammatory response is protective and limits host damage. It is when this acute response remains chronically activated that IL6 becomes pathogenic to the host. Chronically elevated IL6 levels lead to chronic inflammation and fibrotic disorders. The heart is a tissue where this temporal regulation of IL6 is very apparent. Studies from myocardial infarction show how short-term IL6 signaling can protect and preserve the heart tissue in response to acute damage, where long term IL6 signaling or an over-production of IL6R protein plays a causal role in cardiovascular disease. Thus, IL6 can be both protective and pathogenic, depending on the kinetics of the host response. [ABSTRACT FROM AUTHOR]

In this article, I trace the historic background of clonal deletion and molecular mimicry, two major pillars underlying our present understanding of autoimmunity and autoimmune disease. Clonal deletion originated as a critical element of the clonal selection theory of antibody formation in order to explain tolerance of self. If we did have complete clonal deletion, there would be major voids, the infamous “black holes”, in our immune repertoire. For comprehensive, protective adaptive immunity, full deletion is necessarily a rare event. Molecular mimicry, the sharing of epitopes among self and non-self antigens, is extraordinary common and provides the evidence that complete deletion of self-reactive clones is rare. If molecular mimicry were not common, protective adaptive immunity could not be all-encompassing. By taking a fresh look at these two processes together we can envision their evolutionary basis and understand the need for regulatory devices to prevent molecular mimicry from progressing to autoimmune disease. [ABSTRACT FROM AUTHOR]

Until recently, autoimmune disease research has primarily been focused on elucidating the role of the adaptive immune system. In the past decade or so, the role of the innate immune system in the pathogenesis of autoimmunity has increasingly been realized. Recent findings have elucidated paradigm-shifting concepts, for example, the implications of "trained immunity" and a dysbiotic microbiome in the susceptibility of predisposed individuals to clinical autoimmunity. In addition, the application of modern technologies such as the quantum dot (Qdot) system and 'Omics' (e.g., genomics, proteomics, and metabolomics) data-processing tools has proven fruitful in revisiting mechanisms underlying autoimmune pathogenesis and in identifying novel therapeutic targets. This review highlights recent findings discussed at the American Autoimmune Related Disease Association (AARDA) 2019 colloquium. The findings covering autoimmune diseases and autoinflammatory diseases illustrate how new developments in common innate immune pathways can contribute to the better understanding and management of these immune-mediated disorders. • The role of the innate immune system in the pathogenesis of autoimmunity is increasingly being realized. • 'Trained immunity' or 'innate immune memory' is a paradigm-shifting concept with broad applications. • Environmental factors, including host-resident microbiota, have a profound effect on autoimmunity • Common innate immune pathways can be targeted for the management of both autoimmune and autoinflammatory diseases. [ABSTRACT FROM AUTHOR]

Oncology has recently undergone a revolutionary change with widespread adoption of immunotherapy for many cancers. Immunotherapy using monoclonal antibodies against checkpoint molecules, including programmed death (PD)-1, PD ligand (PD-L)1, and cytotoxic T lymphocyte-associated antigen (CTLA)-4, is effective in a significant subset of patients. However, immune-related adverse events (irAEs) have emerged as frequent complications of checkpoint blockade, likely due to the physiological role of checkpoint pathways in regulating adaptive immunity and preventing autoimmunity. As immunotherapy becomes more common, a better understanding of the etiology of irAEs and ways to limit these events is needed. At the same time, studying these new therapy-related disorders provides an opportunity to better understand naturally occurring human autoimmune and inflammatory disorders, with the potential to improve therapies for cancer and autoimmune diseases. IrAEs represent a major obstacle for safely administering checkpoint blockade in cancer patients. Developing methods to minimize irAEs while maintaining effective antitumor immunity could make immunotherapy safer for more cancer patients. Diverse mechanisms likely drive irAEs, which may share varying degrees of similarities and differences with spontaneous autoimmunity. IrAEs that develop following checkpoint blockade in cancer provide an opportunity to better understand spontaneous autoimmune and inflammatory disorders. A deeper understanding of why some patients develop irAEs and others do not is needed to determine who is at highest risk for developing life threatening irAEs and to develop biomarkers to identify these individuals. Improvements in managing, investigating, and reporting on these irAEs are needed to reduce clinical challenges and maximize opportunities to learn from irAEs. [ABSTRACT FROM AUTHOR]

In the broad field of autoimmunity and clinical immunology, experimental evidence over the past few years have demonstrated several connections between the immune system and the nervous system, both central and peripheral, leading to the definition of neuroimmunology and of an immune-brain axis. Indeed, the central nervous system as an immune-privileged site, thanks to the blood-brain barrier, is no longer a dogma as the barrier may be altered during chronic inflammation with disruptive changes of endothelial cells and tight junctions, largely mediated by adenosine receptors and the expression of CD39/CD73. The diseases that encompass the neuroimmunology field vary from primary nervous diseases such as multiple sclerosis to systemic conditions with neuropsychiatric complications, such as systemic lupus erythematosus or vasculitidies. Despite potentially similar clinical manifestations, the pathogenesis of each condition is different, but the interaction between the ultra-specialized structure that is the nervous system and inflammation mediators are crucial. Two examples come from anti-dsDNA cross-reacting with anti- N -Methyl- d -Aspartate receptor (NMDAR) antibodies in neuropsychiatric lupus or the new family of antibody-associated neuronal autoimmune diseases including classic paraneoplastic syndromes with antibodies directed to intracellular antigens (Hu, Yo, Ri) and autoimmune encephalitis. In the case of multiple sclerosis, the T cell paradigm is now complicated by the growing evidence of a B cell involvement, particularly via aquaporin antibodies, and their influence on Th1 and Th17 lineages. Inspired by a productive AARDA-sponsored colloquium among experts we provide a critical review of the literature on the pathogenesis of different immune-mediated diseases with neurologic manifestations and we discuss the basic immunology of the central nervous system and the interaction between immune cells and the peripheral nervous system. [ABSTRACT FROM AUTHOR]

Precision Medicine is an emerging approach for disease treatment and prevention that takes into account individual variability in genes, environment, and lifestyle. Autoimmune diseases are those in which the body's natural defense system loses discriminating power between its own cells and foreign cells, causing the body to mistakenly attack healthy tissues. These conditions are very heterogeneous in their presentation and therefore difficult to diagnose and treat. Achieving precision medicine in autoimmune diseases has been challenging due to the complex etiologies of these conditions, involving an interplay between genetic, epigenetic, and environmental factors. However, recent technological and computational advances in molecular profiling have helped identify patient subtypes and molecular pathways which can be used to improve diagnostics and therapeutics. This review discusses the current understanding of the disease mechanisms, heterogeneity, and pathogenic autoantigens in autoimmune diseases gained from genomic and transcriptomic studies and highlights how these findings can be applied to better understand disease heterogeneity in the context of disease diagnostics and therapeutics. [ABSTRACT FROM AUTHOR]

Research associating the increased prevalence of familial autoimmunity with neuropsychiatric disorders is reliant upon the ascertainment of history of autoimmune diseases from relatives. To characterize the accuracy of self-report, we compared self-reported diagnoses of 18 autoimmune diseases using an online self-report questionnaire to the electronic medical record (EMR) diagnoses in 1,013 adult (age 18–70 years) patients of a primary care clinic. For the 11 diseases meeting our threshold observed prevalence, we estimated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for self-reported diagnoses under the assumption that EMR-based diagnoses were accurate. Six diseases out of 11 had either sensitivity or PPV below 50%, with the lowest PPV for dermatological and endocrinological diseases. Common errors included incorrectly self-reporting type 2 diabetes mellitus (DM), when type 1 DM was indicated by the EMR, and reporting rheumatoid arthritis when osteoarthritis was indicated by the EMR. Results suggest that ascertainment of familial autoimmunity through self-report contributes to inconsistencies and inaccuracies in studies of autoimmune disease history and that future studies would benefit from incorporating EMR review and biological measures. [ABSTRACT FROM AUTHOR]

The extensive, diverse communities that constitute the microbiome are increasingly appreciated as important regulators of human health and disease through inflammatory, immune, and metabolic pathways. We sought to elucidate pathways by which microbiota contribute to inflammatory, autoimmune cardiac disease. We employed an animal model of experimental autoimmune myocarditis (EAM), which results in inflammatory and autoimmune pathophysiology and subsequent maladaptive cardiac remodeling and heart failure. Antibiotic dysbiosis protected mice from EAM and fibrotic cardiac dysfunction. Additionally, mice derived from different sources with different microbiome colonization profiles demonstrated variable susceptibility to disease. Unexpectedly, it did not track with segmented filamentous bacteria (SFB)-driven Th17 programming of CD4 + T cells in the steady-state gut. Instead, we found disease susceptibility to track with presence of type 3 innate lymphoid cells (ILC3s). Ablating ILCs by antibody depletion or genetic tools in adoptive transfer variants of the EAM model demonstrated that ILCs and microbiome profiles contributed to the induction of CCL20/CCR6-mediated inflammatory chemotaxis to the diseased heart. From these data, we conclude that sensing of the microbiome by ILCs is an important checkpoint in the development of inflammatory cardiac disease processes through their ability to elicit cardiotropic chemotaxis. [ABSTRACT FROM AUTHOR]

Introduction Complete Freund's Adjuvant (CFA) emulsified with an antigen is a widely used method to induce autoimmune disease in animal models, yet the contribution of CFA to the immune response is not well understood. We compared the effectiveness of CFA with Incomplete Freund's Adjuvant (IFA) or TiterMax Gold Adjuvant (TMax) in experimental autoimmune myocarditis (EAM) in male mice. Methods EAM was induced in A/J, BALB/c, and IL6KO BALB/c male mice by injection of the myocarditogenic peptide in CFA, IFA, or TMax on days 0 and 7. EAM severity was analyzed by histology on day 21. In addition, specific flow cytometry outcomes were evaluated on day 21. Results Only mice immunized with CFA and myocarditogenic peptide on both days 0 and 7 developed substantial myocarditis as measured by histology. We observed a significantly increased level of IL6 in the spleen 3 days after CFA immunization. In the spleen and heart on day 21, there was an expansion of myeloid cells in CFA-immunized mice, as compared to IFA or TMax-immunized animals. Recombinant IL-6 at the time of IFA immunization partially restored susceptibility of the mice to EAM. We also treated EAM-resistant IL-6 knockout mice with recombinant IL-6 around the time of the first immunization, on days −1 to 2, completely restoring disease susceptibility, showing that the requirement for IL-6 coincides with primary immunization. Examining APC populations in the lymph node draining the immunization site evidenced the contribution of IL-6 to the CFA-dependence of EAM was through controlling local dendritic cell (DC) trafficking. Conclusions CFA used with myocarditogenic peptide twice is required to induce EAM in both A/J and Balb/c mice. Although IFA and TiterMax induce antibody responses, only CFA preferentially induced autoantigen-specific responses. CFA expands monocytes in the heart and in the spleen. IL-6 signaling is required during short window around primary immunization to induce EAM. In addition, IL-6 deficient mice resistance to EAM could be reversed by injecting IL-6 around first immunization. IL-6 expands dendritic cell and monocytic populations and ultimately leads to a robust T-cell driven immune response in CFA immunized mice. [ABSTRACT FROM AUTHOR]

Diabetic cardiomyopathy (DC) is an independent phenotype of diabetic cardiovascular disease. The understanding of the pathogenesis of DC in young patients with type 1 diabetes (T1D) is limited. The cardiac insults of diabetic ketoacidosis (DKA) and progression of DC could include development of antibodies (Abs) to cardiac self-antigens (SAgs) such as: myosin (M), vimentin (V) and k-alpha 1 tubulin (Kα1T). The goal of this study is to determine if the insults of severe DKA and its inflammatory cascade are associated with immune responses to SAgs. Development of Abs to the SAgs were determined by an ELISA using sera collected at three time points in relation to severe DKA (pH < 7.2). Results demonstrate significant differences between the development of Abs to VIM and a previously reported diastolic abnormality (DA) during DKA and its treatment and a NDA group at 2–3 months post DKA (p = 0.0452). A significant association is present between T1D duration (<3 years) and Abs to Kα1T (p = 0.0134). Further, Abs to MYO and VIM are associated with inflammatory cytokines. We propose that severe DKA initiates the synthesis of Abs to cardiac SAgs that are involved in the early immunopathogenesis of DC in young patients with T1D. [ABSTRACT FROM AUTHOR]

Autoimmune diseases include 80 or more complex disorders characterized by self-reactive, pathologic immune responses in which genetic susceptibility is largely insufficient to determine disease onset. In September 2010, the National Institute of Environmental Health Sciences (NIEHS) organized an expert panel workshop to evaluate the role of environmental factors in autoimmune diseases, and the state of the science regarding relevant mechanisms, animal models, and human studies. The objective of the workshop was to analyze the existing data to identify conclusions that could be drawn regarding environmental exposures and autoimmunity and to identify critical knowledge gaps and areas of uncertainty for future study. This consensus document summarizes key findings from published workshop monographs on areas in which "confident" and "likely" assessments were made, with recommendations for further research. Transcribed notes and slides were reviewed to synthesize an overview on exposure assessment and questions addressed by interdisciplinary panels. Critical advances in the field of autoimmune disease research have been made in the past decade. Collaborative translational and interdisciplinary research is needed to elucidate the role of environmental factors in autoimmune diseases. A focus on exposure assessment methodology is needed to improve the effectiveness of human studies, and more experimental studies are needed to focus on causal mechanisms underlying observed associations of environmental factors with autoimmune disease in humans. [ABSTRACT FROM AUTHOR]