Many acquired bleeding and thrombotic complications are provoked by autoantibodies to blood coagulation factors, or to hemostasis inhibitors and regulatory proteins. If occurrence of those antibodies remains rare or ultra-rare, affected patients are not always well-identified and associated pathologies are not always understood. Today, autoantigens tend to be better characterized. New available methods allow investigating structural changes of body components, responsible for auto-immunization. This renders it possible to develop laboratory assays for detecting autoantibodies and estimating their blood concentration. This review analyzes the major autoantibodies reported to be associated with hemorrhagic or thrombotic pathologies and their possible inducing causes when known. Pathogenicity is strongly patient- and context-dependent and is related to autoantibodies’ concentration, avidity, and capacity to bind to autoantigen structures in-vivo, misdirecting the immune system to the own body’s cells or organs. Identification of autoantigens allows for developing laboratory methods for testing autoantibodies and following their evolution kinetics. In-vitro investigations concern functional assays, to evaluate autoantibody’s capacity to inhibit physiological activities, or autoantigen-capture-based assays to detect autoantibodies, like with enzyme-linked immuno-sorbent assay (ELISA) methods. Exploring patients with autoimmune complications remains difficult as few specific assays are available. They mainly concern diseases with the highest incidence, like anti-phospholipid antibodies, lupus anticoagulants, or heparin-dependent antibodies. The present understanding suggests that antibodies to ubiquitous components, like phospholipids or polysaccharides, are actually targeted to proteins with a strong affinity binding to those components: Autoantibodies are not directed to phospholipids, but to phospholipid-binding proteins, and heparin-dependent antibodies are not directed to anticoagulant polysaccharides, but to platelet factor 4. Most pathogenic autoantibodies are of immunoglobulin G (IgG) isotype, but in some cases, IgM or IgA isotypes can be involved. Identification and characterization of autoantibodies associated to hemorrhagic or thrombotic pathologies remains complex at the laboratory level, although they are of high relevance for the right management of concerned patients.

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Chronic rhinosinusitis with nasal polyps (CRSwNP) is a multifactorial inflammatory disease of the mucous membranes of the nose and paranasal sinuses. Eosinophilic inflammation is described as a common endotype. The anti-interleukin-5 (IL-5) antibody mepolizumab was approved in November 2021 as an add-on therapy to intranasal glucocorticosteroids for the treatment of adults with severe CRSwNP when systemic glucocorticosteroids or surgery do not provide adequate disease control. While national and international recommendations exist for the use of mepolizumab in CRSwNP, therapy monitoring and follow-up documentation are required, and therapy discontinuation has not been adequately established yet. In this paper, recommendations for monitoring the course and efficacy of therapy as well as for reviewing the duration and possible termination of therapy are provided. For this purpose, a literature search was performed to analyze previous data on the treatment of CRSwNP with mepolizumab and to determine the available evidence by searching MEDLINE, PubMed, and the national and international trial and guideline registries and the Cochrane Library. Human studies published in the period up to and including October 2022 were considered. Based on the international literature and previous experience, recommendations for follow-up, adherence to therapy intervals and possible therapy breaks, as well as termination of therapy when using mepolizumab for the indication CRSwNP in the German health care system are given by an expert panel on the basis of a documentation sheet.

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In patients with autoimmune coagulation factor deficiency (AiCFD), the production of autoantibodies that inhibit coagulation factors in the blood reduces the activity of those relevant coagulation factors, resulting in severe bleeding symptoms. Recently, reports of patients with AiCFD have noted the concomitant detection of lupus anticoagulant (LA), a risk factor for thrombosis. LA-positive patients may show bleeding symptoms due to decreased activity of coagulation factor II (FII) caused by autoantibodies against FII, in addition to thrombotic symptoms, a condition termed LA-hypoprothrombinemia syndrome (LAHPS). Anti-FII antibodies in LAHPS cases are frequently cleared antibodies that can be detected using immunological techniques, such as enzyme-linked immunosorbent assay (ELISA). Recently, several cases of coagulation FV inhibitors, known as autoimmune FV deficiency, have been reported. Some of these cases may be complicated by LA, which can cause thrombosis. False-positive results for anticoagulant inhibitors are known to occur in LA cases; therefore, immunological confirmation of antibodies against coagulation factors is recommended. Additionally, acquired hemophilia A (AHA), caused by autoantibodies against FVIII, is a typical acquired hemorrhagic diathesis, although affected patients may present with thrombosis associated with LA. Thus, it is important to remember that hemorrhagic diathesis due to autoantibodies against clotting factors can also result in thrombosis, as demonstrated by the co-detection of LA. When clotting factor inhibitors are detected in LA-positive individuals, it is important to confirm the presence of autoantibodies against coagulation factors using immunological methods, such as ELISA, to avoid false-positive results.

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Excitotoxicity represents a neuropathological process, describing the toxic actions of excitatory neurotransmitters, where the excessive or prolonged activation of glutamate receptors triggers a cascade of events leading to neuronal injury or death. Under conditions of reduced energy availability and increased oxidative stress neurons become particularly vulnerable to excitotoxicity and a large body of available evidence indicates that excitotoxicity represents a central mechanism in the pathogenesis of acute and degenerative diseases of the central nervous system. Astrocytes represent key elements in the regulation of glutamate homeostasis by their opposing functions of glutamate uptake and release, and microglial cells play an important role in the response to damage. Depending on the phenotype they assume when activated, microglial cells can trigger immune defense or neuroprotective processes. To perform their functions both glial cell populations monitor the extracellular space through a panel of receptors. Furthermore, a variety of signaling pathways also contribute to the modulation of the glutamatergic transmission, acting on specific cell receptors expressed by neurons, astrocytes, and microglia. In the last decades, evidence has been provided that receptors of almost all families can establish structural receptor-receptor interactions, leading to the formation of heteroreceptor complexes at the cell membrane of neurons and glial cells. The cooperativity that emerges in the actions of ligands of the monomers forming these assemblies provides the cell decoding apparatus with flexible dynamics in terms of recognition and signal transduction and allows an integration of the incoming signals already at the membrane level. Available data on possible modulatory roles played by heteroreceptor complexes in excitotoxic processes will be here reviewed and discussed. From the pharmacological standpoint, these findings may offer possibilities to explore novel therapeutic strategies targeting receptor complexes to address disorders of the central nervous system associated with dysregulation of glutamatergic signaling.

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Mitochondria are present in all mammalian cells except matured red blood cells. Mitochondria consist of several metabolic pathways for glucose, fatty acids, amino acids, and bioenergetic pathways for ATP synthesis, membrane potential, and reactive oxygen production. In the liver, hepatic mitochondria play a key role in hepatic steatosis because mitochondrial metabolism produces acetyl-CoA which is the building block for synthesis of lipids and cholesterol. Mitochondria inner membrane is impermeable of metabolites, reducing equivalents, and small molecules such as phosphate, and sulfate. Thus, mitochondrial shuttles and carriers function as the routes of influx and efflux of these metabolites and molecules across the inner membrane. The signal regulation of these shuttles and mitochondrial enzymes could play a key role in coordinating the mitochondrial metabolism to adapt the cytosolic part of metabolic pathways in liver metabolic stress. Intriguingly, the interaction of mitochondria protein SH3 domain-binding protein 5 (SAB/SH3BP5) and c-Jun N-terminal kinase (JNK) was found as a pivotal role in sustained activation of JNK and phosphorylated-JNK (P-JNK) mediated activation of lipogenic pathway in nutritional excess. Knockout or knockdown of SAB prevented or reversed the hepatic steatosis, inflammation, and fibrosis, and improved metabolic intolerance and energy expenditure. Moreover, blocking the SAB peptide prevents palmitic acid-induced P-JNK interaction with SAB and inhibition of mitochondrial bioenergetics, implying the P-JNK effect on mitochondrial metabolism. This review focuses on the flow of mitochondrial metabolites in metabolic stress conditions and the contribution of mitochondria and mitochondrial stress signals in hepatic steatosis.

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Allergic and immunologic skin diseases are becoming increasingly common and this requires clinicians to be able to recognize and diagnose them. A joint meeting (GET TOGETHER 2022) of the Italian Society of Allergy, Asthma and Clinical Immunology (SIAAIC) and the Italian Society of Allergological, Occupational and Environmental Dermatology (SIDAPA) aimed to review the current knowledge on the differential diagnosis of contact dermatitis, atopic dermatitis, hereditary angioedema, urticaria, and cutaneous mastocytosis. The most important aspects to take into consideration when faced with a new cutaneous manifestation are the clinical features of the lesions, their distribution, age of onset, and comorbidities/aggravating factors. The document does not aim to provide an exhaustive and comprehensive description of all allergic and immunologic skin diseases. Instead, it should be a reference tool for the clinician who is faced with the onset of a new skin manifestation and its differential diagnosis.

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