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Microbial and Environmental Factors in Autoimmune and Inflammatory Diseases

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451555 Year: Pages: 193 DOI: 10.3389/978-2-88945-155-5 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General) --- Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2017-08-28 14:01:09
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In recent years there has been a substantial increase in the number of diseases with the inflammatory component such as such as allergy, asthma, rheumatoid arthritis, inflammatory bowl disease (IBD, which includes ulcerative colitis and Crohn's disease), chronic sinusitis, and many other conditions. The majority of these diseases are multifactorial, with the contribution of genetic and environmental factors. Among the latter, the role of certain microorganisms and viruses in triggering or sustaining the inflammatory process is most controversial. In rheumatoid arthritis, for example, the following bacteria and viruses have been implicated in triggering the disease: Mycoplasma spp., Proteus mirabilis, Escherichia coli, Staphylococcus spp., Bordetella spp., Acinetobacter spp., the parvoviruses, Epstein-Barr virus, and retroviruses. The list of putative microbial triggers of rheumatoid arthritis is still growing, and it becomes essentially impossible to make a causation link between certain infectious agents and the disease. In the light of these disappointing results there are calls for even larger studies with the use of more advanced and large-scale technologies. The primary function of the immune system is the maintenance of body homeostasis and protection against any threats to it via several lines of elaborate and complex immune defense. Given even higher complexity that involves the microbiota and the corresponding host-microbe interaction, the conditions for this equilibrium become even more challenging. In the absence of a defined pathogen, for example, the spectrum of microorganisms involved in triggering inappropriate immune responses may include polymicrobial communities or the cumulative effect of several microbial/viral factors. Under the normal circumstances there is a fine-tuned balance between commensal microbiota and the host’s immune responses. However, when this balance is compromised, for example in IBD, a massive immune response is launched against commensal microbiota resulting in chronic inflammation. Besides the microbial/viral factors, the balance of the immune system can be compromised by other causes. Given, for example, the close and inclusive interaction of the immune, nervous and endocrine systems, the list of these provoking factors can expand even more. For instance, it has been demonstrated that even mild sleep deprivation may increase the production of interleukin-6 and C-reactive protein. Understanding the complex role of microbial and environmental factors in inflammatory and autoimmune diseases, therefore, is the main subject of this topic.

Type I Interferon in Human Autoimmunity

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193400 Year: Pages: 87 DOI: 10.3389/978-2-88919-340-0 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-03-10 08:14:32
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The type I interferon system plays a critical role in host defense in health, and a growing body of literature suggests that type I interferon is a critical mediator of human autoimmune disease. Type I interferons function as a bridge between the innate and adaptive immune systems, and as such play an important role in setting thresholds for response against self antigens. Many investigators have focused on the role type I interferons play in autoimmune disease. This fascinating and rapidly growing body of literature encompasses many different autoimmune diseases, including systemic lupus erythematosus, type I diabetes, multiple sclerosis, and others. In this Research Topic, we provide a comprehensive overview of the various roles type I interferons play in autoimmune diseases, with a focus on human immunology.

Toll-Like Receptor Activation in Immunity vs. Tolerance

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196364 Year: Pages: 75 DOI: 10.3389/978-2-88919-636-4 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-04-07 11:22:02
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The innate immune system has evolved means to recognize and react suitably to foreign entities such as infectious agents. In many cases infectious microorganisms threaten the integrity and function of the target organs or tissues; therefore, consequent to their recognition the immune system becomes activated to ensure their elimination. Toll-like receptors (TLR) constitute a family of receptors specialized in the recognition of molecular patterns typically associated with infectious agents. Different TLRs exist, each selective for molecular entities and motifs belonging to a specific pathogen group. Consequently, it is thought that the molecular nature of invading microorganisms activates specific TLRs to drive adequate anti-infectious immunity. For instance, nucleic acid-specific, intracellular receptors (TLR3/7/8/9) are used to sense viruses and drive antiviral immunity, while other receptors (such as TLR2 and TLR4) recognize and promote immunity against bacteria, yeast, and fungi. Yet, it is becoming evident that activation of TLR pathways trigger mechanisms that not only stimulate but also regulate the immune system. For instance, TLR stimulation by viruses will drive antiviral interferon but also immunoregulatory cytokine production and regulatory T cell activation. Stimulation of TLRs by bacteria or using molecular agonists can also trigger both immune stimulatory and regulatory responses. TLR stimulation by infectious agents likely serves to activate but also control anti-infectious immunity, for instance prevent potential immunopathological tissue damage which can be caused by acute immune defense mechanisms. Previous work by us and others has shown that the immunoregulatory arm of TLR stimulation can additionally help control autoreactive processes in autoimmune disease. Hence, it is becoming established that gut commensals, which also play a crucial part in the control of autoimmune disease, establish immune regulatory mechanisms through activation of particular TLRs. In sum, it appears that TLRs are key immune players that not only stimulate but also regulate immune processes in health and disease. In this Research Topic, we wish to review the dual role of TLRs as activators and regulators of immune responses. We aim to motivate data-driven opinions as to the importance of context of TLR agonism for determining immune activation vs. regulation. The presentation of ongoing original works, as well as data and opinions around other innate immune receptors pertaining to this topic, are also encouraged.

Autism Spectrum Disorders (ASD) - Searching for the Biological Basis for Behavioral Symptoms and New Therapeutic Targets

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451128 Year: Pages: 178 DOI: 10.3389/978-2-88945-112-8 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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Autism Spectrum Disorder (ASD) is currently diagnosed based on a series of behavioral tests. The challenge for researchers is to try to uncover the biological basis for these typical behaviors in order to improve diagnosis and identify potential targets for treatment. A multidisciplinary approach is necessary in order to move forward. This includes analysis of the current animal models for ASD and their suitability, reviewing immunological, immunogenetic and epigenetic research, reassessing clinical diagnostic tools, and surveying radiological, pathological, and serological records for clues. This volume includes research from some of the leading researchers on ASD. We are hopeful that it will stimulate further dialogue and research in this challenging field.

Pathophysiology and Imaging Diagnosis of Demyelinating Disorders

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ISBN: 9783038429432 9783038429449 Year: Pages: X, 168 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Neurology
Added to DOAB on : 2018-06-27 15:51:32
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Demyelinating disorders are chronic autoimmune disorders characterized by inflammation, demyelination, axonal degeneration, and neuronal loss. They have complex pathophysiology and diverse clinical presentations. The etiology of these disorders lies in the interaction between genetic and environmental factors. Due to the complexity in pathophysiology and presentation, diagnosis and treatment can be challenging. Advanced technology, including modern imaging techniques, as well as optical coherence tomography (OCT), enrich our understanding of the disease process, improve diagnostic accuracy, and may guide treatment decisions.

The Association of Other Autoimmune Diseases in Patients With Thyroid Autoimmunity

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889456253 Year: Pages: 118 DOI: 10.3389/978-2-88945-625-3 Language: English
Publisher: Frontiers Media SA
Subject: Internal medicine --- Medicine (General)
Added to DOAB on : 2019-01-23 14:53:43
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Autoimmune thyroid diseases (AITD) are T cell-mediated organ-specific autoimmune disorders resulting from an immune dysregulation leading to a thyroid immune attack (Antonelli and Benvenga). Graves’ disease and Hashimoto’s thyroiditis are the two main clinical presentations of AITD, and their clinical hallmarks are thyrotoxicosis and hypothyroidism, respectively. In many cases, AITD may be associated in the same patient with other organ-specific autoimmune attacks (such as in the case of type II autoimmune polyglandular syndrome, or type I diabetes, etc). Furthermore, AITD and thyroid function abnormalities have been frequently described in patients with systemic rheumatologic autoimmune diseases. Conversely, patients affected with the above mentioned autoimmune disorders are more frequently affected by AITD.In this Research Topic, constituted by nineteen papers, we review and discuss new evidence about the association of other autoimmune diseases in patients with AITD. Among other organ-specific autoimmune disorders, the associations of AITD with chronic autoimmune gastritis (Cellini et al.), vitiligo (Baldini E et al.), lichen (Guarneri et al.), psoriasis (Ruffilli et al.), myasthenia gravis (Lopomo and Berrih-Aknin) and glomerulopathies (Santoro et al.) have been treated. Also the associations of AITD, in systemic autoimmune diseases have been treated (as Sjögren’s syndrome, Baldini C et al.; systemic sclerosis, Fallahi et al.; systemic lupus erythematosus, Ferrari et al.; Antiphospholipid syndrome, Versini; sarcoidosis, Fazzi et al.; the autoimmune/inflammatory syndrome induced by adjuvants, Watad et al.; rheumatoid arthritis, Bliddal et al.; Hepatitis C Virus and mixed cryoglobulinemia, Ferri et al.; and, psoriathic arthritis, Ruffilli et al.). Furthermore peculiar aspects associated with post partum thyroiditis have been reviewed too (Di Bari et al., Le Donne et al.).The exact pathogenetic mechanisms underlying the above reported associations are not completely known. It has been hypothesized that the influence of genetic (Coppedè), and environmental factors (Antonelli and Benvenga), could lead to the onset of autoimmune phenomena in different organs in the same subject, characterized by predominance of a Th1 immune pattern at the beginning, and in the active phase of these disorders.In conclusion, an association of other autoimmune diseases in patients with thyroid autoimmunity has been shown, and this Research Topic provides an extensive update of the literature, and suggests interesting points for new investigations.

Evolution of NK-mediated target recognition under the pressure of physiologic or pathologic stimuli

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194520 Year: Pages: 190 DOI: 10.3389/978-2-88919-452-0 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-02-05 17:24:33
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Since their discovery NK cells have come out as potential tools to fight cancer and viruses. This finding early urged different groups to study the mechanisms governing NK cell function. The identification of the MHC-I-specific inhibitory receptors (i.e. KIRs, NKG2A and certain Ly49 molecules) allowed defining rather rapidly how NK cells could avoid self-aggression and how they could be directed towards targets that were forced, by viral infection or tumor transformation, to down-regulate MHC-I expression. In a second time, also the repertoire of surface activating receptors addressing NK cytotoxicity towards tumors and pathogens was mostly defined. In spite of the first findings, however, most recent studies may suggest that NK cells and their receptors might not have been evolved to kill tumor targets and, perhaps, they might have been only partially influenced, in their evolution, by the need of recognizing viruses. Indeed certain NK receptors known to activate NK cell cytotoxicity (NKp30, DNAM-1, NKp80) can also participate at regulatory interactions occurring between NK and myeloid cells. In addition, a peculiar NK cell subset which intensively populate decidua during the first trimester of pregnancy, through the engagement of specific receptors and the interaction with decidual DC, produce chemokines and pro-angiogenic cytokines, and induce Tregs. Thus, in this context, NK cells favor decidua vascularization and development of the (semiallogeneic) foetus in a tolerant environment. Viruses have nevertheless played an important role in shaping the NK cell receptor repertoire. Several studies have unveiled clues of the evolutionary struggle between these pathogens and NK cells. Different NK receptors, including NKp46, NKp30, NKp44, NKG2D, NKG2C, Ly49, and certain KIRs have been demonstrated to recognize virus-encoded or virus-induced ligands. The expression of TLR specifically recognizing microbial products, together with the unexpected role of KIR3DL2 in shuttling these products to TLR-containing endosomes have also been documented in NK cells. On the other side, different viral immune evasion molecules have been shown to interfere with the expression of ligands for T or NK cell activating receptors. In addition, viral infections can occur in the reproductive stage of life cycle, and may represent a serious threat for the species propagation. Thus the control of viruses, together with the maintenance of foetus during pregnancy, should represent major evolutionary forces in shaping NK-receptors. Along this line, the NK-mediated control of tumors should not be under the same evolutionary pressure, as tumors mostly appear later in the life cycle, and the recognition of tumor-encoded ligands may be less efficient (as the NK cell receptors might have not been selected for such aim). This may be the reason why, although displaying strong antitumor activity in vitro, NK cells could hardly contain tumor burden in vivo. In addition the pathogen-driven evolution of NK cell function may also favor the role of NK cells in the insurgence of immune-mediated diseases. This research topic will collect contributions that may clarify the relationships between the evolution of the NK receptors and their role in an efficient recognition of viruses and tumor cells or in immune-mediated diseases.

Recent advances in Pancreatology

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193332 Year: Pages: 69 DOI: 10.3389/978-2-88919-333-2 Language: English
Publisher: Frontiers Media SA
Subject: Nutrition and Food Sciences --- Medicine (General) --- Physiology --- Science (General)
Added to DOAB on : 2016-03-10 08:14:32
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Pancreatic diseases include intractable ones including acute and chronic pancreatitis, and pancreatic cancer. In recent years, great advances have been made in the field of pancreatology, including the pathogenesis, diagnostic modalities, and development of novel therapeutic interventions. It has been established that pancreatic stellate cells play a pivotal role in the development of pancreatic fibrosis in chronic pancreatitis as well as in pancreatic cancer known as desmoplastic reaction. Although it might be still controversial, accumulating evidence has shown that interaction between pancreatic stellate cells-cancer cells contribute to the progression of pancreatic cancer through the increased proliferation and migration, and production of cytokines and extracellular matrix components. In addition, pancreatic stellate cells lead to the resistance to chemotherapy and radiation therapy. Pancreatic stellate cells attract the researchers as a novel therapeutic target of pancreatic cancer. Genetic studies have shown that mutations in the trypsin-related genes such as cationic trypsinogen (PRSS1) gene and the serine protease inhibitor, Kazal type 1 (SPINK1) gene are associated with pancreatitis. In general, each of these factors appears to limit trypsin activation or enhance inactivation, and is believed to increase intrapancreatic trypsin activity and predispose to pancreatitis when the gene is mutated. These results have supported a concept that pancreatic protease/anti-protease plays pivotal roles in the pathogenesis of pancreatitis. In addition, genetic studies focusing on phenotypic variances would provide us with important information how genetic variants would affect the phenotypic variances. Autophagy is an intracellular bulk degradation system in which cytoplasmic components are directed to the lysosome/vacuole by a membrane-mediated process. Recent studies have highlighted a role of autophagy in acute pancreatitis. Using a conditional knockout mouse that lacks the autophagy-related (Atg) gene Atg5 in the pancreatic acinar cells, autophagy exerts a detrimental effect in pancreatic acinar cells by activation of trypsinogen to trypsin. A theory in which autophagy accelerates trypsinogen activation by lysosomal hydrolases under acidic conditions, thus triggering acute pancreatitis in its early stage. The epithelial-mesenchymal transition is a developmental process that allows a polarized epithelial cell to undergo multiple biochemical changes that enable it to assume a mesenchymal phenotype. The phenotype associated with epithelial-mesenchymal transition includes enhanced migratory capacity, invasiveness, elevated resistance to apoptosis, and greatly increased production of extracellular matrix components. In addition to its role in development, tissue regeneration, and fibrosis, epithelial-mesenchymal transition is now considered as a critical process in cancer progression. Induction of epithelial-mesenchymal transition in cancer cells results in the acquisition of invasive and metastatic properties. Epithelial-mesenchymal transition could be an important mechanism in the progression of pancreatic cancer and its poor prognosis. Autoimmune pancreatitis is a unique form of pancreatitis in which autoimmune mechanisms are suspected to be involved in the pathogenesis. There is accumulating study to deal with this new disease concept. In addition to these topics, we have selected several topics in pancreatology, focusing on recent studies increasingly deepening our knowledge in both basic and clinical researches.

Histamine H4 receptor. A Novel Drug Target For Immunoregulation and Inflammation

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ISBN: 9788376560564 Year: Pages: 368 DOI: 10.2478/9788376560564 Language: English
Publisher: De Gruyter
Subject: Biochemistry
Added to DOAB on : 2014-03-05 13:31:51
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H4R is the newest member of the histamine receptor family, which was discovered about twelve years ago. It is considered a very promising drug target. The effort to improve the pharmacokinetic properties of the currently available H4R ligands is reflected in a steadily growing number of scientific publications and patent applications. Preclinical data strongly confirms the need for novel potent H4R ligands to explore their therapeutic value in allergy, inflammation, autoimmune disorders, and possibly, cancer. Readers will be provided with extensive knowledge on histamine metabolism, as well as cellular histamine transport, storage and release, effects of histamine and histamine receptor ligands, with particular attention to the H4R, on inflammatory cells including mast cells, basophils, eosinophils, neutrophils, macrophages, dendritic cells, and T cells. The present knowledge on the regulatory role of histamine and the therapeutic exploitation of histamine receptor ligands in atopic diseases, with emphasis on human and animal models of asthma, allergic dermatitis and pruritus are discussed.

Lymphocytes in MS and EAE: More than just a CD4+ World

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889453023 Year: Pages: 160 DOI: 10.3389/978-2-88945-302-3 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2018-02-27 16:16:45
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Multiple sclerosis is degenerative disease of the central nervous system (CNS) in which myelin destruction and axon loss leads to the accumulation of physical, cognitive, and mental deficits. MS affects more than a million people worldwide and managing this chronic disease presents a significant health challenge. Multiple lines of evidence indicate that MS is an autoimmune disorder in which immune cells launch an inflammatory attack targeting myelin antigens. Indeed, myelin-reactive T cells and antibodies have been identified in MS patients and in animal models (namely experimental autoimmune encephalomyelitis, or EAE) that recapitulate many features of human disease. Animal model studies have demonstrated that T cells are both necessary and sufficient to initiate and sustain CNS autoimmunity. However, most MS animal models rely on the role played by CD4+ T cells and partially replicate the multiple aspects of MS pathogenesis. Thus, research in the past has focused heavily on the contribution of CD4+ T cells to the disease process; searching PubMed for “MS AND CD4” yields twice the results as corresponding searches for “CD8” or “B cell” and four times that for “NK cells”. While CD4+ T cells may represent the minimum requirement to mediate CNS autoimmunity, it is clear that the immune response underlying human MS is far more complex and involves numerous other immune cells and subsets. This is well illustrated by the observation that MS patients treated with an anti-CD4 depleting antibody did not gain any clinical benefits whereas removal of several lymphocyte subsets using an anti-CD52 depleting antibody has been shown to impede disease progression. In particular, the pathogenic role(s) of non-CD4+ T cell lymphocytes is relatively poorly understood and under-researched, despite evidence that these subsets contribute to disease pathology or regulation. For example, the observed oligoclonal expansion of CD8+ T cells within the CNS compartment supports a local activation. CD8+ T cells with polarized cytolytic granules are seen in close proximity to oligodendrocytes and demyelinated axons in MS tissues. The presence of B cells in inflammatory lesions and antibodies in the CSF have long been recognized as features of MS and Rituximab, a B cell depleting therapy, has been shown to be highly effective to treat MS. Intriguingly, the putative MS therapeutic reagent Daclizumab may function in part through the expansion of a subset of immunoregulatory NK cells. NKT and ?d T cells may also play a role in CNS autoimmunity, given that they respond to lipid antigens and that myelin is lipid-rich. While different animal models recapitulate some of these aspects of human disease, identifying appropriate models and measures to investigate the role of these less well-understood lymphocytes in MS remains a challenge for the field. This Frontiers research topic aims to create a platform for both animal- and human-focused researchers to share their original data, hypotheses, future perspectives and commentaries regarding the role of these less-well understood lymphocyte subsets (CD8+ T cells, B cells, NK cells, NK T cells, ?d T cells) in the pathogenesis of CNS autoimmunity.

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