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Iskalni niz: "ključne besede" (mast cells) .

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1.
Heritable risk for severe anaphylaxis associated with increased [alpha]-tryptase-encoding germline copy number at TPSAB1
Jonathan J. Lyons, Jack Chovanec, Michael P. O'Connell, Yihui Liu, Julij Šelb, Roberta Zanotti, Yun Bai, Jiwon Kim, Quang T. Le, Tom DiMaggio, Matija Rijavec, Peter Korošec, 2020

Povzetek: Background: An elevated basal serum tryptase level is associated with severe systemic anaphylaxis, most notably caused by Hymenoptera envenomation. Although clonal mast cell disease is the culprit in some individuals, it does not fully explain this clinical association. Objective: Our aim was to determine the prevalence and associated impact of tryptase genotypes on anaphylaxis in humans. Methods: Cohorts with systemic mastocytosis (SM) and venom as well as idiopathic anaphylaxis from referral centers in Italy, Slovenia, and the United States, underwent tryptase genotyping by droplet digital PCR. Associated anaphylaxis severity (Mueller scale) was subsequently examined. Healthy volunteers and controls with nonatopic disease were recruited and tryptase was genotyped by droplet digital PCR and in silico analysis of genome sequence, respectively. The effects of pooled and recombinant human tryptases, protease activated receptor 2 agonist and antagonist peptides, and a tryptase-neutralizing mAb on human umbilical vein endothelial cell permeability were assayed using a Transwell system. Results: Hereditary [alpha]-tryptasemia (H[alpha]T)--a genetic trait caused by increased [alpha]-tryptase-encoding Tryptase-[alpha]/[beta]1 (TPSAB1) copy number resulting in elevated BST level--was common in healthy individuals (5.6% [n = 7 of 125]) and controls with nonatopic disease (5.3% [n = 21 of 398]). H[alpha]T was associated with grade IV venom anaphylaxis (relative risk = 2.0; P < .05) and more prevalent in both idiopathic anaphylaxis (n = 8 of 47; [17%; P = .006]) and SM (n = 10 of 82 [12.2%; P = .03]) relative to the controls. Among patients with SM, concomitant H[alpha]T was associated with increased risk for systemic anaphylaxis (relative risk = 9.5; P = .007). In vitro, protease-activated receptor-2-dependent vascular permeability was induced by pooled mature tryptases but not [alpha]- or [beta]-tryptase homotetramers. Conclusions: Risk for severe anaphylaxis in humans is associated with inherited differences in [alpha]-tryptase-encoding copies at TPSAB1.
Ključne besede: mastocytosis, venoms, hypersensitivity, anaphylaxis - diagnosis, mast cells, idiopathic anaphylaxis, mast cell activation, hereditary alpha-tryptasemia
DiRROS - Objavljeno: 11.09.2020; Ogledov: 768; Prenosov: 142

2.
Mast cell activation test in the diagnosis of allergic disease and anaphylaxis
Rajia Bahri, Adnan Custovic, Peter Korošec, Marina Tsoumani, Martin Barron, Jiakai Wu, Rebekah Sayers, Alf Weimann, Monica Ruiz-Garcia, Nandinee Patel, Mira Šilar, 2018

Povzetek: Background. Food allergy is an increasing public health issue and the commonest 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 resulting in over-diagnosis and adverse impact on health-related quality of life. Objective. To undertake initial validation and assessment of a novel diagnostic tool, the mast cell activation test (MAT). Methods. Primary human mast cells (hMCs) were generated from peripheral blood precursors, and sensitized using patient sera and then incubated with allergen. Mast cell degranulation was assessed by flow cytometry and mediator release. We compared the diagnostic performance of MAT to existing diagnostic tools to assess in a cohort of peanut-sensitized individuals undergoing double-blind, placebo-controlled challenge. Results. hMCs sensitized with sera from peanut, grass pollen and hymenoptera- (wasp venom) allergic patients demonstrated allergen-specific and dose-dependent degranulation by both expression of surface activation markers (CD63 and CD107a) and functional assays (prostaglandins D2 and ß-hexosaminidase release). In this cohort of peanut-sensitized individuals, MAT was found to have superior discrimination performance compared to other testing modalities including component-resolved diagnostics and basophil activation test. Using functional principle component analysis, we identified 5 clusters or patterns of reactivity in the resulting dose-response curves, which at preliminary analysis corresponded to the reaction phenotypes seen at challenge. Conclusion. MAT is a robust tool which may confer superior diagnostic performance compared to existing allergy diagnostics, and may be useful to explore differences in effector cell function between basophils and mast cells during allergic reactions.
Ključne besede: allergy and immunology -- diagnosis, anaphylaxis, immunologic tests, mast cells, food hypersensitivity, basophil activation test, BAT, mast cell activation test
DiRROS - Objavljeno: 30.11.2020; Ogledov: 631; Prenosov: 305
.pdf Celotno besedilo (3,30 MB)

3.
Cold agglutinins and cryoglobulins associate with clinical and laboratory parameters of cold urticaria
Mojca Bizjak, Mitja Košnik, Dorothea Terhorst, Dejan Dinevski, Marcus Maurer, 2021

Povzetek: Mast cell-activating signals in cold urticaria are not yet well defined and are likely to be heterogeneous. Cold agglutinins and cryoglobulins have been described as factors possibly associated with cold urticaria, but their relevance has not been explained. We performed a single-center prospective cohort study of 35 cold urticaria patients. Cold agglutinin and cryoglobulin test results, demographics, detailed history data, cold stimulation test results, complete blood count values, C-reactive protein, total immunoglobulin E levels, and basal serum tryptase levels were analyzed. Forty six percent (n = 16) of 35 tested patients had a positive cold agglutinin test and 27% (n = 9) of 33 tested patients had a positive cryoglobulin test. Cold agglutinin positive patients, when compared to cold agglutinin negative ones, were mainly female (P = 0.030). No gender-association was found for cryoglobulins. A positive cold agglutinin test, but not a positive cryoglobulin test, was associated with a higher rate of reactions triggered by cold ambient air (P = 0.009) or immersion in cold water (P = 0.041), and aggravated by increased summer humidity (P = 0.007). Additionally, patients with a positive cold agglutinin test had a higher frequency of angioedema triggered by ingestion of cold foods or drinks (P = 0.043), and lower disease control based on Urticaria Control Test (P = 0.023). Cold agglutinin levels correlated with erythrocyte counts (r = -0.372, P = 0.028) and monocyte counts (r = -0.425, P = 0.011). Cryoglobulin concentrations correlated with basal serum tryptase levels (r = 0.733, P = 0.025) and cold urticaria duration (r = 0.683, P = 0.042). Results of our study suggest that cold agglutinins and cryoglobulins, in a subpopulation of cold urticaria patients, are linked to the course and possibly the pathogenesis of their disease.
Ključne besede: urticaria, mast cells, cold-induced urticaria, cold urticaria, cryoglobulins, cold agglutinin, degranulation, clinical parameters, laboratory parameters
DiRROS - Objavljeno: 10.05.2021; Ogledov: 307; Prenosov: 271
.pdf Celotno besedilo (1,61 MB)

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