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Important and specific role for basophils in acute allergic reactions
Peter Korošec, Bernhard F. Gibbs, Matija Rijavec, Adnan Custovic, Paul J. Turner, 2018, review article

Abstract: IgE-mediated allergic reactions involve the activation of effector cells, predominantly through the high-affinity IgE receptor (FceRI) on mast cells and basophils. Although the mast cell is considered the major effector cell during acute allergic reactions, more recent studies indicate a potentially important and specific role for basophils and their migration which occurs rapidly upon allergen challenge in humans undergoing anaphylaxis. We review the evidence for a role of basophils in contributing to clinical symptoms of anaphylaxis, and discuss the possibility that basophil trafficking during anaphylaxis might be a pathogenic (to target organs) or protective (preventing degranulation in circulation) response. Finally, we examine the potential role of basophils in asthma exacerbations. Understanding the factors that regulate basophil trafficking and activation might lead to new diagnostic and therapeutic strategies in anaphylaxis and asthma.
Keywords: allergy and immunology, basophils, anaphylaxis
Published in DiRROS: 14.12.2020; Views: 1117; Downloads: 741
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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, original scientific article

Abstract: 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.
Keywords: allergy and immunology -- diagnosis, anaphylaxis, immunologic tests, mast cells, food hypersensitivity, basophil activation test, BAT, mast cell activation test
Published in DiRROS: 30.11.2020; Views: 1435; Downloads: 892
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Hereditary angioedema due to C1-inhibitor deficiency in Macedonia : clinical characteristics, novel SERPING1 mutations, and genetic factors modifying the clinical phenotype
Vesna Grivčeva-Panovska, Mitja Košnik, Peter Korošec, Slađana Andrejević, Ljerka Karadža-Lapić, Matija Rijavec, 2018, original scientific article

Abstract: Objective: Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is a rare disease, characterized by swellings. We aimed to characterize on a clinical and molecular basis C1-INH-HAE patients in the Republic of Macedonia. Results: All 15 patients from six unrelated families were diagnosed with C1-INHHAE type I, with a mean age of symptom onset of 11 years and an average delay of diagnosis of 7 years. Patients reported on average 31 angioedema attacks/year, with a median clinical severity score (CSS) of 7. We identified three known mutations, and two mutations (c.813_818delCAACAA and c.1488T>G) were reported for the first time. To address the genotype-phenotype association, a pooled analysis including 78 C1-INH-HAE south-eastern European patients was performed, with additional analysis of F12-46C/T and KLKB1- 428G/A polymorphisms. We demonstrated that patients with nonsense and frameshift mutations, large deletions/insertions, splicing defects, and mutations at Arg444 exhibited an increased CSS compared with missense mutations, excluding mutations at Arg444. In addition, the CC F12-46C/T polymorphism was suggestive of earlier disease onset. Discussion: Genetic analysis helped identify the molecular basis of C1-INH-HAE given that causative mutations in SERPING1 were detected in all patients, including an infant before the appearance of clinical symptoms. We identified two novel mutations and further corroborated the genotype-phenotype relationship, wherein mutations with a clear effect on C1-INH function predispose patients to a more severe disease phenotype and CC F12-46C/T predisposes patients to earlier disease onset.
Keywords: hereditary angioedemas -- genetics -- Macedonia, C1 inhibitor, SERPING1 gene, C1 inhibitor, SERPING1 gene
Published in DiRROS: 30.11.2020; Views: 1112; Downloads: 244
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Systemic and airway oxidative stress in competitive swimmers
Sabina Škrgat, Peter Korošec, Izidor Kern, Mira Šilar, Julij Šelb, Matjaž Fležar, Robert Marčun, 2018, original scientific article

Abstract: Background: The environment in swimming pools, which contain chlorine, might interact with the airway epithelium, resulting in oxidative stress and/or inflammation during high intensity training periods. Methods: We evaluated pulmonary functional (metacholine challenge test, FEV1 and VC), cellular (eosinophils and neutrophils), inflammatory (FeNo, IL-5, IL-6, IL-8 and TNF-[alpha]), oxidative (8-isoprostanes) and angiogenesis factors (VEGF) in induced sputum and peripheral blood of 41 healthy non-asthmatic elite swimmers (median 16 years) during the period of high intensity training before a national championship. The second paired sampling was performed seven months later after training had been stopped for one month. Results: There was a ten-fold increase (median 82-924 pg/ml; P < 0.001) in 8-isoprostanes in induced sputum and five-fold increase (median 82-924 pg/ml; P < 0.001) in sera during training in comparison to the period of rest. However, there was no difference in FEV1 (113 vs 116%), VC (119 vs 118%), FeNo (median 34 vs 38 ppb), eosinophils (2.7 vs 2.9% in sputum; 180 vs 165 cells/[micro]l in blood), neutrophils, different cytokines or VEGF in induced sputum or sera. The only exception was TNF-[alpha], which was moderately increased in sera (median 23 vs 40 pg/ml; P=0.02) during the peak training period. Almost half (18 of 41) of swimmers showed bronchial hyperresponsiveness during the peak training period (PC20 cutoff was 4 mg/ml). There was no correlation between hyperresponsiveness and the markers of oxidative stress or inflammation. Conclusions: High intensity training in healthy, non-asthmatic competitive swimmers results in marked oxidative stress at the airway and systemic levels, but does not lead to airway inflammation. However, we could not confirm that oxidative stress is associated with bronchial hyperresponsiveness (AHR), which is often observed during the peak exercise training period.
Keywords: bronchial diseases, swimming, oxidative stress, bronchial hyperresponsiveness, competitive swimmers, training
Published in DiRROS: 23.11.2020; Views: 1459; Downloads: 421
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The culprit insect but not severity of allergic reactions to bee and wasp venom can be determined by molecular diagnosis
Pia Gattinger, Christian Lupinek, Lampros Kalogiros, Mira Šilar, Mihaela Zidarn, Peter Korošec, Christine Koessler, Natalija Novak, Rudolf Valenta, Irene Mittermann, 2018, original scientific article

Abstract: Background. Allergy to bee and wasp venom can lead to life-threatening systemic reactions. The identification of the culprit species is important for allergen-specific immunotherapy. Objectives. To determine a panel of recombinant bee and wasp allergens which is suitable for the identification of bee or wasp as culprit allergen sources and to search for molecular surrogates of clinical severity of sting reactions. Methods. Sera from eighty-seven patients with a detailed documentation of their severity of sting reaction (Mueller grade) and who had been subjected to titrated skin testing with bee and wasp venom were analyzed for bee and wasp-specific IgE levels by ImmunoCAPTM. IgE-reactivity testing was performed using a comprehensive panel of recombinant bee and wasp venom allergens (rApi m 1, 2, 3, 4, 5 and 10; rVes v 1 and 5) by ISAC chip technology, ImmunoCAP and ELISA. IgG4 antibodies to rApi m 1 and rVes v 5 were determined by ELISA and IgE/ IgG4 ratios were calculated. Results from skin testing, IgE serology and IgE/IgG4 ratios were compared with severity of sting reactions. Results. The panel of rApi m 1, rApi m 10, rVes v 1 and rVes v 5 allowed identification of the culprit venom in all but two of the 87 patients with good agreement to skin testing. Severities of sting reactions were not associated with results obtained by skin testing, venom-specific IgE levels or molecular diagnosis. Severe sting reactions were observed in patients showing < 1 ISU and < 2kUA/L of IgE to Api m 1 and/or Ves v 5. Conclusion. We identified a minimal panel of recombinant bee and wasp allergens for molecular diagnosis which may permit identification of bee and/or wasp as culprit insect in venom-sensitized subjects. The severity of sting reactions was not associated with parameters obtained by molecular diagnosis.
Keywords: allergy and immunology -- diagnosis, allergens -- diagnosis, hymenoptera, immunotherapy, bee, wasp, venom, sting reactions, molecular diagnosis, systemic reactions
Published in DiRROS: 23.11.2020; Views: 12337; Downloads: 1451
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Quantitative, absolute count-based T cell analysis of CD69 upregulation as a new methodology for in vitro diagnosis of delayed-type nickel hypersensitivity
Ana Koren, Mira Šilar, Helena Rupnik, Mihaela Zidarn, Peter Korošec, 2019, original scientific article

Abstract: Background: T cells play a major role in delayed-type hypersensitivity reactions. Their reactivity can be assessed by measuring the upregulation of the activation marker CD69, followed by proliferation and cytokine production. The aim of our study was to develop a novel, whole blood-based, quantitative, absolute count activation index (AI) analysis of CD69 upregulation on different subsets of T cells in nickel hypersensitive patients and compare it with the previously reported approaches. Methods: Ten patients with nickel allergy and nine healthy controls were included. CD69 expression of CD3+, CD3+CD4+ and CD3+CD8+ T cells in heparinized blood was determined with flow cytometry after incubation with nickel sulfate for 48 h. The absolute cell count of CD69+ cells was determined with microbeads. The production of the cytokines IL-2, IL-5, IL-13, and IFN-[gamma] was determined after nickel sulfate stimulation of PBMNCs for 48 h. Results: We showed that the most sensitive methodology is the absolute AI, which was calculated as the ratio between the absolute count of CD69-positive T cells stimulated with nickel and the absolute count of CD69-positive T cells in non-stimulated blood. This novel quantitative approach was more discriminative than the previously reported approaches in which T cell CD69 percentage AI and cytokine production are measured. Conclusions: Our results demonstrated that measuring the absolute CD69 AI is an accurate new approach to quantify antigen-specific T cells in the blood of patients with hypersensitivity reactions to nickel. This approach may be useful for better in vitro assessment of patients with delayed-type hypersensitivity reactions.
Keywords: allergy and immunology, delayed hypresensitivity, nickel, blood, CD antigenes, CD69
Published in DiRROS: 18.11.2020; Views: 1073; Downloads: 261
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Epitope mapping of major ragweed allergen Amb a 1
Abida Zahirović, Borut Štrukelj, Peter Korošec, Mojca Lunder, 2019, original scientific article

Abstract: Ragweed is a prominent cause of seasonal allergies. Thus far, information on IgE-binding sites of major allergen in ragweed pollen, Amb a 1, is very limited. A powerful experimental method to gain insights on the allergen epitopes is the selection of peptides from biological libraries that bind to anti-allergen antibodies. In this work, we aimed to map IgE epitopes of Amb a 1 using epitope-mimicking short peptides % mimotopes that were affinity-selected from phage-displayed random peptide libraries. The peptides weakly aligned with the Amb a 1 primary sequence, thus suggesting that the epitopes are conformational. When the peptides were mapped onto the surface of Amb a 1 homology model, the EpiSearch analysis predicted the location of four potential epitopic sites on surface patches centred at residues K104, S110, H214, and W312. The peptides matching to the predicted epitopes bound selectively to the IgE from pool of ragweed-allergic patients% sera and therefore represent mimetics of Amb a 1 IgE epitopes. The knowledge of IgE epitopes is a prerequisite for the rational design of molecular-based approaches to diagnosis and immunotherapy of allergic diseases.
Keywords: allergens, ragweed allergy, Amb a 1, epitope mapping, phage display, mimotopes
Published in DiRROS: 09.11.2020; Views: 1134; Downloads: 802
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CD3+CD4-CD8- mucosal T cells are associated with uncontrolled chronic rhinosinusitis with nasal polyps
Tanja Soklič, Mira Šilar, Matija Rijavec, Ana Koren, Izidor Kern, Irena Hočevar-Boltežar, Peter Korošec, 2019, short scientific article

Abstract: Increased mucosal double-negative (DN) CD3+CD4-CD8- T cells were found for the first time in CRS and were much more abundant in uncontrolled CRSwNP than in well-controlled CRSwNP.
Keywords: chronic rhinosinusitis, CD3+ T-cells, CD4- T-cells, CD8- T-cells
Published in DiRROS: 22.10.2020; Views: 1389; Downloads: 463
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