The Journal of allergy and clinical immunology
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J. Allergy Clin. Immunol. · Aug 2018
Mast cell activation test in the diagnosis of allergic disease and anaphylaxis.
Food allergy is an increasing public health issue and the most common cause of life-threatening anaphylactic reactions. Conventional allergy tests assess for the presence of allergen-specific IgE, significantly overestimating the rate of true clinical allergy and resulting in overdiagnosis and adverse effect on health-related quality of life. ⋯ The MAT is a robust tool that can confer superior diagnostic performance compared with existing allergy diagnostics and might be useful to explore differences in effector cell function between basophils and MCs during allergic reactions.
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J. Allergy Clin. Immunol. · Jun 2018
Sialic acid-binding immunoglobulin-like lectin 8 (Siglec-8) is an activating receptor mediating β2-integrin-dependent function in human eosinophils.
Siglec-8 is a CD33 subfamily cell-surface receptor selectively expressed on human eosinophils. After cytokine priming, Siglec-8 mAb or glycan ligand binding causes eosinophil apoptosis associated with reactive oxygen species (ROS) production. Most CD33-related Siglecs function as inhibitory receptors, but the ability of Siglec-8 to stimulate eosinophil ROS production and apoptosis suggests that Siglec-8 might instead function as an activating receptor. ⋯ These data demonstrate that Siglec-8 functions uniquely as an activating receptor on IL-5-primed eosinophils through a novel pathway involving regulation of β2-integrin-dependent adhesion, NADPH oxidase, and a subset of protein kinases.
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J. Allergy Clin. Immunol. · Jun 2018
IL-12 and IL-7 synergize to control mucosal-associated invariant T-cell cytotoxic responses to bacterial infection.
Bacterial respiratory tract infections and exacerbations of chronic lung diseases are commonly caused by nontypeable Haemophilus influenzae (NTHi). Cell-mediated cytotoxicity might be key to controlling infection, but the responses of NTHi-specific T-cell populations are not well understood. Mucosal-associated invariant T (MAIT) cells are a recently discovered, innate-like subset of T cells with cytotoxic function, the role of which in lung immunity is unclear. ⋯ Overall, our data provide evidence for a cytotoxic role of MAIT cells in the lung and highlight important differences in the control of adaptive and innate-like T-cell responses. Understanding these mechanisms might lead to new therapeutic opportunities to modulate the antibacterial response and improve clinical outcome.
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J. Allergy Clin. Immunol. · Jun 2018
Blood eosinophil count thresholds and exacerbations in patients with chronic obstructive pulmonary disease.
Eosinophilic airway inflammation in patients with chronic obstructive pulmonary disease (COPD) is associated with exacerbations and responsivity to steroids, suggesting potential shared mechanisms with eosinophilic asthma. However, there is no consistent blood eosinophil count that has been used to define the increased exacerbation risk. ⋯ Patients with moderate-to-severe COPD and blood eosinophil counts of 300 cells/μL or greater had an increased risk exacerbations in the COPDGene study, which was prospectively validated in the ECLIPSE study.