6 research outputs found

    Advances and highlights in T and B cell responses to drug antigens

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    The immunological mechanisms involved in drug hypersensitivity reactions (DHRs) are complex, and despite important advances, multiple aspects remain poorly understood. These not fully known aspects are mainly related to the factors that drive towards either a tolerant or a hypersensitivity response and specifically regarding the role of B and T cells. In this review, we focus on recent findings on this knowledge area within the last 2 years. We highlight new evidences of covalent and non-covalent interactions of drug antigen with proteins, as well as the very first characterization of naturally processed flucloxacillin-haptenated human leukocyte antigen (HLA) ligands. Moreover, we have analysed new insights into the identification of risk factors associated with the development of DHRs, such as the role of oxidative metabolism of drugs in the activation of the immune system and the discovery of new associations between DHRs and HLA variants. Finally, evidence of IgG-mediated anaphylaxis in humans and the involvement of specific subpopulations of effector cells associated with different clinical entities are also topics explored in this review. All these recent findings are relevant for the underlying pathology mechanisms and advance the field towards a more precise diagnosis, management and treatment approach for DHRs.Funding for open access charge: Universidad de Málaga / CBUA. This work has been supported by Institute of Health ‘Carlos III’ (ISCIII) of the Ministry of Economy and Competitiveness (MINECO) (grants co-funded by European Regional Development Fund: PI15/01206, PI17/01237, PI18/00095, RETICS ARADYAL RD16/0006/0001). Andalusian Regional Ministry of Health (grants PI-0241-2016, PE-0172-2018, PI-0127-2020). AA holds a Senior Postdoctoral Contract (RH-0099-2020) from Andalusian Regional Ministry of Health (cofunded by European Social Fund (ESF): ‘Andalucía se mueve con Europa’). ML holds a ‘Rio Hortega’ contract (CM20/00210) by ISCIII of MINECO (cofunded by ESF). CM holds a ‘Nicolas Monardes’ research contract by Andalusian Regional Ministry Health (RC-0004-2021)

    Epidemiology, Mechanisms, and Diagnosis of Drug-Induced Anaphylaxis

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    Anaphylaxis is an acute, life-threatening, multisystem syndrome resulting from the sudden release of mediators by mast cells and basophils. Although anaphylaxis is often under-communicated and thus underestimated, its incidence appears to have risen over recent decades. Drugs are among the most common triggers in adults, being analgesics and antibiotics the most common causal agents. Anaphylaxis can be caused by immunologic or non-immunologic mechanisms. Immunologic anaphylaxis can be mediated by IgE-dependent or -independent pathways. The former involves activation of Th2 cells and the cross-linking of two or more specific IgE (sIgE) antibodies on the surface of mast cells or basophils. The IgE-independent mechanism can be mediated by IgG, involving the release of platelet-activating factor, and/or complement activation. Non-immunological anaphylaxis can occur through the direct stimulation of mast cell degranulation by some drugs, inducing histamine release and leading to anaphylactic symptoms. Work-up of a suspected drug-induced anaphylaxis should include clinical history; however, this can be unreliable, and skin tests should also be used if available and validated. Drug provocation testing is not recommended due to the risk of inducing a harmful reaction. In vitro testing can help to confirm anaphylaxis by analyzing the release of mediators such as tryptase or histamine by mast cells. When immunologic mechanisms are suspected, serum-sIgE quantification or the use of the basophil activation test can help confirm the culprit drug. In this review, we will discuss multiple aspects of drug-induced anaphylaxis, including epidemiology, mechanisms, and diagnosis

    Restricted Microbiota and Absence of Cognate TCR Antigen Leads to an Unbalanced Generation of Th17 Cells.

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    International audienceRetinoic acid-related orphan receptor (ROR)Îłt(+) TCRαÎČ(+) cells expressing IL-17, termed Th17 cells, are most abundant in the intestinal lamina propria. Symbiotic microbiota are required for the generation of Th17 cells, but the requirement for microbiota-derived Ag is not documented. In this study, we show that normal numbers of Th17 cells develop in the intestine of mice that express a single TCR in the absence of cognate Ag, whereas the microbiota remains essential for their development. However, such mice, or mice monocolonized with the Th17-inducing segmented filamentous bacteria, fail to induce normal numbers of Foxp3(+) RORÎłt(+) T cells, the regulatory counterpart of IL-17(+)RORÎłt(+) T cells. These results demonstrate that a complex microbiota and cognate Ag are required to generate a properly regulated set of RORÎłt(+) T cells and Th17 cells

    Epidemiology, Mechanisms, and Diagnosis of Drug-Induced Anaphylaxis

    No full text
    Anaphylaxis is an acute, life-threatening, multisystem syndrome resulting from the sudden release of mediators by mast cells and basophils. Although anaphylaxis is often under-communicated and thus underestimated, its incidence appears to have risen over recent decades. Drugs are among the most common triggers in adults, being analgesics and antibiotics the most common causal agents. Anaphylaxis can be caused by immunologic or non-immunologic mechanisms. Immunologic anaphylaxis can be mediated by IgE-dependent or -independent pathways. The former involves activation of Th2 cells and the cross-linking of two or more specific IgE (sIgE) antibodies on the surface of mast cells or basophils. The IgE-independent mechanism can be mediated by IgG, involving the release of platelet-activating factor, and/or complement activation. Non-immunological anaphylaxis can occur through the direct stimulation of mast cell degranulation by some drugs, inducing histamine release and leading to anaphylactic symptoms. Work-up of a suspected drug-induced anaphylaxis should include clinical history; however, this can be unreliable, and skin tests should also be used if available and validated. Drug provocation testing is not recommended due to the risk of inducing a harmful reaction. In vitro testing can help to confirm anaphylaxis by analyzing the release of mediators such as tryptase or histamine by mast cells. When immunologic mechanisms are suspected, serum-sIgE quantification or the use of the basophil activation test can help confirm the culprit drug. In this review, we will discuss multiple aspects of drug-induced anaphylaxis, including epidemiology, mechanisms, and diagnosis
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