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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]

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]

Abstract: Most of our current understanding of the genetic predisposition to autoimmune disease can be traced to experiments performed in the decade from 1971 to 1981. Chella David was a key contributor to this research. Many of these early steps came from studies of experimental autoimmune thyroiditis. This model has been especially valuable because essentially the same disease can occur spontaneously in selected strains of animals or can be induced by deliberate immunization. From a genetic point of view, the disease has been investigated in three different species: mice, rats and chickens. The same antigen, thyroglobulin, initiates the disease in all three species. Among the main discoveries were the relationship of autoimmune disease to the major histocompatibility complex (MHC), the interplay of different subregions within the MHC in promoting or retarding development of disease, the differing roles of MHC class II and MHC I class genes in induction and effector phases, respectively, and the cumulative effect of non-MHC genes, each of which represents a small addition to overall susceptibility. Other experiments revealed that genetic differences in thyroglobulin allotypes influence susceptibility to thyroiditis. Thyroid glands differed in different strains in vulnerability to passive transfer of antibody. The first evidence of modulatory genes on the sex-related X chromosome emerged. All of these genetic findings were concurrently translated to the human disease, Hashimoto’s thyroiditis, where thyroglobulin is also the initiating antigen. [Copyright &y& Elsevier]

Abstract: An epidemiologic study of the autoimmune diseases taken together has not been done heretofore. The National Patient Register of Denmark is used to estimate the population prevalence of 31 possible or probable autoimmune diseases. Record linkage is used to estimate 465 pairwise co-morbidities in individuals among the 31 diseases, and familial aggregation among sibs, parents and offspring. The prevalence of any of the 31 diseases in the population is more than 5%. Within individuals, there is extensive comorbidity across the 31 diseases. Within families, aggregation is strongest for individual diseases and weak across diseases. These data confirm the importance of the autoimmune diseases as a group and suggest that common etiopathologies exist among them. [Copyright &y& Elsevier]

Abstract: Excellent animal models are available for virus-induced and autoimmune heart disease that are remarkably similar to human disease. Developing good animal models for heart disease is crucial because cardiovascular disease is now the leading cause of death in the United States and is estimated to be the leading cause of death in the world by the year 2020. A significant proportion of heart disease in Western populations is associated with inflammation. Myocarditis, or inflammation of the heart muscle, is the major cause of sudden death in young adults. Although most individuals recover from acute myocarditis, genetically susceptible individuals may go on to develop chronic myocarditis and dilated cardiomyopathy (DCM) resulting in congestive heart failure. In this article, we describe a model of autoimmune myocarditis and DCM induced by inoculation with heart-passaged coxsackievirus B3 (CVB3). Intraperitoneal inoculation of susceptible mice with CVB3 induces acute cardiac inflammation from days 7 to 14 postinfection (pi) that progresses to chronic myocarditis and DCM from day 28 to at least 56 pi. The model of CVB3-induced myocarditis presented here allows dissection of the contribution of viral infection and xenobiotics on immune dysregulation and inflammation in the heart. An improved understanding of the interaction between environmental exposures and the development of heart disease represents a clear challenge for immunotoxicologists. [Copyright &y& Elsevier]

Mononuclear cell infiltration of the thyroid gland is a common histologic feature of chronic lymphocytic thyroiditis. Although the infiltrating mononuclear cells have been implicated in the destruction of the thyroid, information concerning the progression of infiltration into the thyroid is limited. In this report, we examine the composition and kinetics of mononuclear cell infiltration in the thyroid and the expression of major histocompatibility complex class II (I-Ak), IL-12, and IFN-γ in the thyroid of the NOD-H2h4 mouse, a model of spontaneous autoimmune thyroiditis accelerated by the administration of excess dietary iodine. Mice were given a low dose of 0.015% NaI in their drinking water for 2, 4, 6, 8, and 16 weeks, and thyroids were removed, serially sectioned, and stained in an avidin-biotin peroxidase assay. The thyroid infiltrate included CD4+ and CD8+ T cells, F4/80+ macrophages, and B220+ B cells. After 2 weeks of iodine treatment, CD4+ T cells were the first seen in the thyroid, followed by CD8+ T cells and F4/80+ macrophages. B220+ B cells entered the thyroid after 4 weeks of iodine treatment. IL-12 and IFN-γ positive cells were located in the thyroid early in disease and were up-regulated in the focal accumulations of infiltrating cells. Thyrocytes clearly expressed I-Ak after 4 weeks of iodine treatment near the location of mononuclear cell infiltration. [Copyright &y& Elsevier]

Mononuclear cell infiltration of the thyroid is a prominent feature of chronic lymphocytic thyroiditis. Adhesion molecules play a major role in determining the localization of inflammatory mononuclear cells in the thyroid. Previous reports from animal models and human studies have described the thyroidal expression of adhesion molecules only late in clinical disease. In this study, we examined the distribution and kinetics of expression of E-selectin, VCAM-1, LFA-1, and ICAM-1 in the NOD-H2h4 mouse, a model of spontaneous autoimmune thyroiditis accelerated by dietary iodine. Mice were fed 0.015% NaI in their drinking water for 2, 4, 6, 8, and 16 weeks, and thyroids were removed, serially sectioned, and stained in an avidin–biotin–peroxidase assay. We found a dramatic increase in E-selectin and VCAM-1 expression on intrathyroidal endothelial cells after 16 weeks of iodine treatment. In addition, we describe for the first time that thyrocytes from the NOD-H2h4 mouse, and the parental NOD, constitutively express ICAM-1 independent of iodine treatment and prior to mononuclear cell infiltration of the thyroid gland. ICAM-1 was not detected on the thyrocytes of other untreated strains of mice, implicating expression of this adhesion molecule as a critical event in the recruitment of inflammatory mononuclear cells to the thyroid. [Copyright &y& Elsevier]

Abstract: This essay honors the lifetime achievements of Julius Cruse. It relates some of my personal experiences of the past and my views of the future in two areas in which Professor Cruse has made lasting contributions—the history of science and scientific communication. We can best chart the future by understanding the past. [Copyright &y& Elsevier]

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]

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]

Abstract: Pregnancy modulates autoimmune diseases through diverse and still incompletely defined mechanisms, in part operating at the decidua–placenta interface. To assess the immunological contribution of placenta, we administered mouse placental proteins to a mouse model of autoimmune hypophysitis, a disease known to be strongly associated with pregnancy. Emulsified placental proteins suppressed both the cellular and humoral aspects of hypophysitis. Suppression was specific to self antigens and not seen when two foreign antigens, tetanus toxoid or tuberculin purified protein derivative, were used. Proteomic analysis revealed high levels of soluble TNF receptor 1 in placenta, suggesting that blockade of the TNF-α pathway was a mechanism of disease suppression. Placentas derived from mice deficient in TNF receptor 1 lost the ability to suppress hypophysitis. Notably, hypophysitis suppression was seen only when the TNF-α pathway was blocked locally, at the site of immunization, and not systemically. These findings provide evidence that placenta contributes to the immune tolerance of pregnancy by locally inhibiting the TNF-α pathway. [Copyright &y& Elsevier]

Abstract: The paradoxical relationship between immunodeficiency (under-responsiveness) and autoimmunity (over-responsiveness) affecting the immune system was debated at the Fourth AARDA Colloquium on cross-disciplinary issues in autoimmunity. Immunodeficiency disease and autoimmune disease, far from being mutually exclusive, share profound dysregulation of the immune system. Among the most keenly discussed issues were: i) the remarkably high number of molecularly identified primary immunodeficiencies with autoimmune expressions; ii) the homeostasis of immune function such that deficiency in any one given compartment can result in over activity in the same or another compartment; iii) whilst some immune deficiency states are essentially monogenic, each of them can exhibit striking variability in autoimmune outcome, indicative of epigenetic or environmental influences on phenotypic expression; iv) innate immunity, particularly complement defects, as well as adaptive immunity, is complicit in the immunodeficiency-autoimmunity axis; v) features of certain of the disorders discussed at the meeting forced a reappraisal of what actually is meant by ‘autoimmune disease’. It was concluded that genes that determine inherited immunodeficiencies, hitherto rather neglected by autoimmunologists, compel attention to consideration of molecular genetic anomalies critical for emergence of autoimmune disease in humans and animals. [ABSTRACT FROM AUTHOR]

Abstract: Despite the widespread use of cardiac troponins as biomarkers for the diagnosis and quantitation of cardiac injury, the effect of troponin release and a possible autoimmune response to the troponins is unknown. Other investigators reported that programmed cell death-1 (PD-1)-receptor deficient mice developed severe cardiomyopathy with autoantibodies to troponin I. We found that immunization of genetically susceptible mice with troponin I but not troponin T induced a robust autoimmune response leading to marked inflammation and fibrosis in the myocardium. At later times, antibodies to cardiac myosin were detected in troponin-immunized mice. The severity of inflammation correlated with expression of chemokines RANTES, MIP-2, IP-10 and MCP-1 in the myocardium. Prior immunization with troponin I increased the severity of experimental infarctions, indicating that an autoimmune response to troponin I aggravates acute cardiac damage. Cardiac inflammation, fibrosis and functional impairment were transferred from immunized to naive recipients by CD4+ T cells, and the cytokine profile suggested both Th2 and Th17 profiles in A/J mice. Finally we identified an 18-mer of troponin I containing an immuno-dominant epitope. [Copyright &y& Elsevier]

Abstract: In April 2007, an international Colloquium bridging scientific and clinical disciplines was held to discuss the role of cellular and tissue damage in the initiation, development and persistence of autoimmune disease. Five potential etiologic and pathophysiologic processes fundamental to autoimmune disease (i.e. inflammation, infection, apoptosis, environmental exposure and genetics) were the focus of the presentations and integrative discussions at the Colloquium. The information presented on these topics is condensed in this review. Inflammation has close clinico-pathologic associations with autoimmunity, but future analyses will require better definition and metrics of inflammation, particularly for the earliest cellular and molecular components dependent on recruitment of elements of innate immunity. Although infection may be associated with increased levels of autoantibodies, most infections and virtually all vaccinations in humans lack well-established links to autoimmune diseases. Further application of well-designed, long-term epidemiologic and population-based studies is urgently needed to relate antecedent exposures with later occurring stigmata of autoimmunity with a goal of discerning potentially susceptible individuals or subpopulations. Suspect infections requiring closer interrogation include EB virus (SLE and other diseases), HCV (autoimmune hepatitis), beta hemolytic streptococci (rheumatic carditis) and Helicobacter pylori (autoimmune gastritis) among others. And even if a micro-organism was to be incriminated, mechanisms of initiation/perpetuation of autoimmunity continue to challenge investigators. Plausible mechanisms include potentiation and diversion of innate immunity; exposure or spillage of intracellular autoantigens; or provision of autoantigenic mimics. Integrity of apoptosis as a critical safeguard against autoimmunity was discussed in the contexts of over-reactivity causing autoantigens to gain enhanced exposure to the immune system, or under-reactivity producing insufficient elimination of autoreactive clones of lymphocytes. Although environmental agents are widely believed to serve as necessary “triggers” of autoimmune disease in genetically predisposed individuals, only a few such agents (mainly drugs and some nutrients) have been clearly identified and their mechanism of action defined. Finally an essential genetic foundation underlies all these hazards for autoimmunity in the form of risk-associated polymorphisms in immunoregulatory genes. They may be predictive of future or impending disease. [Copyright &y& Elsevier]

Chemokines represent a group of small, secreted proteins mainly involved in navigating leukocytes towards site of inflammation. Some chemokines have been implicated in the pathogenesis of autoimmune diseases, which are characterized by an ectopic retention of leukocytes within the target organ, ultimately leading to loss of function. To determine the chemokines profile expressed in the thyroid gland upon chronic exposure to interferon-gamma (IFNγ), we analyzed C57BL6 transgenic mice that aberrantly express IFNγ under control of the thyroglobulin promoter. We compared by reverse transcriptase PCR the thyroidal expression of 10 chemokines (CCL1 through 5 and CXCL9 through 13) in thyr-IFNγ transgenics and wild-type littermates. We found that transgenics exclusively expressed CCL4, CXCL9, and CXCL11, and showed increased expression of CCL5 and CXCL10. This chemokine profile was associated with moderate mononuclear cell infiltration of the thyroid stroma that, however, decreased significantly after 2 months of age and did not organize into lymphoid structures. Our findings indicate that the isolated expression of IFNγ is capable of recruiting mononuclear cells but they do not progress to full lymphoid transformation of the thyroid. [Copyright &y& Elsevier]

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]

Abstract: Increasing evidence supports a role for the environment in the development of autoimmune diseases, as reviewed in the accompanying three papers from the National Institute of Environmental Health Sciences Expert Panel Workshop. An important unresolved issue, however, is the development of criteria for identifying autoimmune disease phenotypes for which the environment plays a causative role, herein referred to as environmentally associated autoimmune diseases. There are several different areas in which such criteria need to be developed, including: 1) identifying the necessary and sufficient data to define environmental risk factors for autoimmune diseases meeting current classification criteria; 2) establishing the existence of and criteria for new environmentally associated autoimmune disorders that do not meet current disease classification criteria; and 3) identifying in clinical practice specific environmental agents that induce autoimmune disease in individual patients. Here we discuss approaches that could be useful for developing criteria in these three areas, as well as factors that should be considered in evaluating the evidence for criteria that can distinguish individuals with such disorders from individuals without such disorders with high sensitivity and specificity. Current studies suggest that multiple lines of complementary evidence will be important and that in many cases there will be clinical, serologic, genetic, epigenetic, and/or other laboratory features that could be incorporated as criteria for environmentally associated autoimmune diseases to improve diagnosis and treatment and possibly allow for preventative strategies in the future. [Copyright &y& Elsevier]

Abstract: The mechanisms leading to autoimmune diseases remain largely unknown despite numerous lines of experimental inquiry and epidemiological evidence. The growing number of genome-wide association studies and the largely incomplete concordance for autoimmune diseases in monozygotic twins support the role of the environment (including infectious agents and chemicals) in the breakdown of tolerance leading to autoimmunity via numerous mechanisms. The present article reviews the major theories on the mechanisms of the environmental influence on autoimmunity by addressing the different degrees of confidence that characterize our knowledge. The theories discussed herein include (i) the role of innate immunity mediated by toll-like receptors in triggering the autoimmune adaptive response characterizing the observed pathology; (ii) changes in spleen marginal zone B cells in autoantibody production with particular focus on the B10 subpopulation; (iii) Th17 cell differentiation and T regulatory cells in the aryl hydrocarbon receptor model; (iv) self antigen changes induced by chemical and infectious agents which could break tolerance by post-translational modifications and molecular mimicry; and finally (v) epigenetic changes, particularly DNA methylation, that are induced by environmental stimuli and may contribute to autoimmunity initiation. We are convinced that these working hypotheses, in most cases supported by solid evidence, should be viewed in parallel with animal models and epidemiological observations to provide a comprehensive picture of the environmental causes of autoimmune diseases. [Copyright &y& Elsevier]

Abstract: A protective effect of interferon-gamma (IFNγ) has been described in a number of models of autoimmune disease, including experimental autoimmune myocarditis (EAM). Some reports have suggested that regulation of apoptosis in autoreactive lymphocytes mediate these protective functions. We examined the potential of IFNγ to regulate apoptotic mechanisms in detail, both in vitro and in vivo in EAM. We observed multiple apoptotic defects in caspase activity, and the expression of TNF superfamily members on CD4+ T cells. In addition, we observed selective defects in CD4+ T cell activation in response to antigenic stimulation. These activation and apoptotic defects were CD4+ cell autonomous, independent of the genotype of APCs. Inhibition of nitric oxide production in vivo did not reproduce the severe form of EAM of IFNγ-deficient mice, indicating that this pathway does not mediate the protective effect of IFNγ. Crosswise adoptive transfer of wild type, IFNγ− / −, and IFNγR− / −EAM demonstrated that IFNγ signaling was critical in CD4+ cells, but that non-CD4+ sources of IFNγ production were also involved in the control of disease. Together, these data indicate multiple mechanisms of autonomous and non-autonomous CD4+ T cell regulation mediated by IFNγ in the control of autoimmune heart disease. [ABSTRACT FROM AUTHOR]

Abstract: The incidence of cardiovascular disease, including inflammatory heart diseases like myocarditis, is increased in men. Similarly, male BALB/c mice infected with coxsackievirus B3 (CVB3) develop more severe acute inflammation in the heart compared to females. To better understand the effect of male sex hormones on cardiac inflammation, we gonadectomized (Gdx) male BALB/c mice and examined acute CVB3-induced myocarditis compared to sham controls. Viral replication in the heart was not significantly altered between Gdx and sham mice. However, gonadectomy significantly reduced testosterone levels and inflammation in the heart. FACS analysis of cell populations isolated from the heart revealed that CD11b+ cells were significantly reduced in Gdx males. However, a GR1+F4/80+ subset of CD11b+ cells was significantly increased. Because this subset also expressed the interleukin (IL)-4R and IL-10, we refer to these cells as “alternatively activated” or M2 macrophages. A greater percentage of M2 macrophages in Gdx males expressed the inhibitory receptor Tim-3, while fewer expressed IL-1β and IL-10. Only M2 macrophages upregulated TLR4 and Tim-3, whereas GR1−IL-4Rlo macrophages did not. Additionally, IL-4+CD4+ Th2 cells, Foxp3+ regulatory T (Treg) cells and Tim-3+CD4+ T cells were significantly increased in the heart following Gdx. Thus, we report for the first time that the inhibitory receptor Tim-3 is expressed on M2 macrophages. Our findings show that sex hormones and/or other mediators released from the testes inhibit anti-inflammatory populations in the heart including Tim-3+ M2, Tim-3+CD4+ T cells, Th2 and Treg resulting in more severe acute cardiac inflammation in males following CVB3 infection. [Copyright &y& Elsevier]

Abstract: MIP-2 and IFN-γ inducible protein-10 (IP-10) and their respective receptors, CXCR2 and CXCR3, modulate tissue inflammation by recruiting neutrophils or T cells from the spleen or bone marrow. Yet, how these chemokines modulate diseases such as immune-mediated drug-induced liver injury (DILI) is essentially unknown. To investigate how chemokines modulate experimental DILI in our model we used susceptible BALB/c (WT) and IL-4−/− (KO) mice that develop significantly reduced hepatitis and splenic T cell priming to anesthetic haptens and self proteins following TFA-S100 immunizations. We detected CXCR2+ splenic granulocytes in all mice two weeks following immunizations; by three weeks, MIP-2 levels (p <0.001) and GR1+ cells were elevated in WT livers, suggesting MIP-2-recruited granulocytes. Elevated splenic CXCR3+CD4+T cells were identified after two weeks in KO mice indicating elevated IP-10 levels which were confirmed during T cell priming. This result suggested that IP-10 reduced T cell priming to critical DILI antigens. Increased T cell proliferation following co-culture of TFA-S100-primed WT splenocytes with anti-IP-10 (p <0.05) confirmed that IP-10 reduced T cell priming to CYP2E1 and TFA. We propose that MIP-2 promotes and IP-10 protects against the development of hepatitis and T cell priming in this murine model. [Copyright &y& Elsevier]

Abstract: We previously identified by linkage analysis a region on chromosome 1 (Eam1) that confers susceptibility to experimental autoimmune myocarditis (EAM). To evaluate the role of Eam1, we created a congenic mouse strain, carrying the susceptible Eam1 locus of A.SW on the resistant B10.S background (B10.A-Eam1 congenic) and analyzed three outcomes: 1) the incidence and severity of EAM, 2) the susceptibility of lymph node cells (LNCs) to Cy-enhanced cell death, and 3) susceptibility of lymphoctyes to antigen-induced cell death. Incidence of myocarditis in B10.A-Eam1 congenic mice was comparable to A.SW mice, confirming that Eam1 plays an important role in disease development. Caspase 3, 8 and 9 activation in LNCs following Cy treatment and in CD4+ T cells after immunization with myosin/CFA was significantly lower in A.SW than B10.S mice whereas B10.A-Eam1 congenic mice exhibited an intermediate phenotype. Our results show that Eam1 reduces lymphocyte apoptosis and increases susceptibility to EAM. [Copyright &y& Elsevier]

Abstract: Clinical evidence suggests that idiosyncratic hepatitis following administration of halogenated volatile anesthetics is mediated by autoimmune responses. No murine model to study mechanisms of anesthetic-induced or any other form of drug-induced idiosyncratic hepatitis exists. Anesthetics are believed to trigger hepatitis by covalently linking a trifluoroacetyl (TFA) chloride hapten to hepatic proteins, forming haptenated self-proteins. To test this hypothesis, we developed a hapten-induced model of hepatitis by immunization with syngeneic S100 liver proteins covalently coupled to TFA (TFA-S100). We found that TFA-S100 induced hepatitis was more severe than disease induced by S100 plus adjuvants or by the adjuvant alone and was characterized by neutrophil, mast cell, and eosinophil infiltration. TFA-specific IgG1 antibodies directly correlated with hepatitis, whereas S100 autoantibodies did not. TNF-α, IL-1β, and IL-6 released from splenocytes collected 2 weeks after TFA-S100 inoculation were increased resembling the elevated serum cytokines reported in patients with autoimmune hepatitis (AIH). Three weeks after inoculation, the peak of hepatitis, we noted decreased numbers of Kupffer cells and lower levels of IL-6 and IL-10 in the liver, cytokines produced by Kupffer cells. This is the first report, to our knowledge, of a hapten-induced model of hepatitis with immune and autoimmune features. [Copyright &y& Elsevier]

We have recently reported that IL17A−/− animals are protected from progression of experimental autoimmune myocarditis (EAM) to dilated cardiomyopathy (DCM) as determined by echocardiography on day 54. IL17A−/− mice had lower IL6 levels in their heart compared with wildtype (WT) BALB/c animals. This was the only cytokine found to differ significantly between the two groups at both days 14 and 21. To investigate the IL6 requirement for DCM development we used two experimental approaches. First, we over-expressed IL6 in WT and IL17A−/− animals through hydrodynamic gene delivery (HGD) on days −1 or 7 of EAM. Mice over-expressing IL6 showed worsening of heart function compared to controls. Second, we blocked IL6R signaling using an anti-IL6R monoclonal antibody (mAb) in WT mice with EAM. Mice administered the anti-IL6R mAb on days 7 and 14 or 14 and 21 of EAM were protected from heart failure and DCM development by day 54 of disease. At day 14 of EAM there was reduced STAT3 phosphorylation in the heart after anti-IL6R mAb administration and increased STAT3 phosphorylation following HGD of IL6. In the mice receiving anti-IL6R mAb there was a significant decrease in the total number of CD45+ cells infiltrating the heart as measured by flow cytometry with similar composition in controls. Mice over-expressing IL6, both WT and IL17A−/− genotypes, had more CD11b+F4/80+ macrophages as well as CD11b+Ly6G+ neutrophils in the heart. IL6R mAb treated mice had lower circulating complement C3 levels where over-expressing mice had higher C3 levels than controls. Our data suggest that in EAM IL6 promotes the development of DCM during early events around day 7. [ABSTRACT FROM AUTHOR]