Seminars in immunopathology
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Review
The immunopathogenesis of celiac disease reveals possible therapies beyond the gluten-free diet.
Celiac disease is a T cell-mediated autoimmune inflammatory disease of the small intestine that is activated by gluten. The diagnosis of celiac disease is challenging as patients display a wide range of symptoms and some are asymptomatic. A lifelong gluten-free diet is the only currently approved treatment of celiac disease. ⋯ Strategies that limit T cell migration to the small intestine or that reestablish mucosal homeostasis and tolerance to gluten antigens are also being explored. Additionally, it is vital to develop new therapeutic options for refractory celiac disease patients. This review highlights therapeutic strategies that may ultimately improve the health and well-being of individuals with celiac disease.
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Transition metals are essential nutrients to virtually all forms of life, including bacterial pathogens. In Staphylococcus aureus, metal ions participate in diverse biochemical processes such as metabolism, DNA synthesis, regulation of virulence factors, and defense against oxidative stress. As an innate immune response to bacterial infection, vertebrate hosts sequester transition metals in a process that has been termed "nutritional immunity." To successfully infect vertebrates, S. aureus must overcome host sequestration of these critical nutrients. The objective of this review is to outline the current knowledge of staphylococcal metal ion acquisition systems, as well as to define the host mechanisms of nutritional immunity during staphylococcal infection.
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The parallel expression of activation products of the coagulation, fibrinolysis, and complement systems has long been observed in both clinical and experimental settings. Several interconnections between the individual components of these cascades have also been described, and the list of shared regulators is expanding. ⋯ However, dysregulation of the cascade activities or functions of inhibitors in one or both systems can result in clinical manifestations of disease, such as sepsis, systemic lupus erythematosus, or ischemia-reperfusion injury, with critical thrombotic and/or inflammatory complications. An appreciation of the precise relationship between complement activation and thrombosis may facilitate the development of novel therapeutics, as well as improve the clinical management of patients with thrombotic conditions that are characterized by complement-associated inflammatory responses.
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In the pathogenesis of sepsis, inflammation and coagulation play a pivotal role. Increasing evidence points to an extensive cross-talk between these two systems, whereby inflammation not only leads to activation of coagulation but coagulation also considerably affects inflammatory activity. The intricate relationship between inflammation and coagulation may not only be relevant for vascular atherothrombotic disease in general but has in certain clinical settings considerable consequences, for example in the pathogenesis of microvascular failure and subsequent multiple organ failure, as a result of severe infection and the associated systemic inflammatory response. ⋯ Pro-inflammatory cytokines and other mediators are capable of activating the coagulation system and downregulating important physiological anticoagulant pathways. Activation of the coagulation system and ensuing thrombin generation is dependent on an interleukin-6-induced expression of tissue factor on activated mononuclear cells and endothelial cells and is insufficiently counteracted by physiological anticoagulant mechanisms and endogenous fibrinolysis. Interestingly, apart from the overall systemic responses, a differential local response in various vascular beds related to specific organs may occur.
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Review
Microparticles: a critical component in the nexus between inflammation, immunity, and thrombosis.
Plasma membrane remodeling characterized by phosphatidylserine exposure and consecutive microparticle (MP) shedding is an ubiquitous process enabling the clearance of senescent cells and the maintenance of tissue homeostasis. MPs are released as fragments from the budding plasma membrane of virtually all eukaryotic cell types undergoing stimulation or apoptosis and may be considered a broad primitive response to stress. MP release is dependent on cytoskeleton degradation pathways involving caspases, requires a sustained increase in intracellular calcium triggering K+ and Cl- efflux and is possibly tuned by mitochondria permeability changes. ⋯ Because of their multiple properties that are characteristic of a private response of the parental cell, MPs could act as cytoprotective and anti-inflammatory agents through the delivery of activated protein C or annexin 1 and could contribute to the limitation of vascular hyporeactivity. Owing to their ability to cargo bioactive signals, MPs could be viewed as an integrated communication network enabling the coordination of complex cellular responses in biological fluids and the maintenance of the homeostasis equation. A better understanding of the molecular mechanisms involved in MP shedding would pave the way of a new pharmacological approach aiming at the control of MP-driven cellular responses.