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Query: "author" (Julij Šelb) .

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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

Abstract: 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.
Keywords: mastocytosis, venoms, hypersensitivity, anaphylaxis - diagnosis, mast cells, idiopathic anaphylaxis, mast cell activation, hereditary alpha-tryptasemia
DiRROS - Published: 11.09.2020; Views: 470; Downloads: 63

Worldwide perspectives on venom allergy
Peter Korošec, Thilo Jakob, Harfi Harb, Robert Heddle, Sarah Karabus, Ricardo de Lima Zollner, Julij Šelb, Bernard Yu-Hor Thong, Fares Zaitoun, David B. K. Golden, Michael Levin, 2019

Abstract: Venom immunotherapy is the standard of care for people with severe reactions and has been proven to reduce risk of future anaphylactic events. There is a moral imperative to ensure production, supply and worldwide availability of locally relevant, registered, standardized commercial venom extracts for diagnosis and treatment. Insects causing severe immediate allergic reactions vary by region worldwide. The most common culprits include honeybees (Apis mellifera), social wasps including yellow jackets (Vespula and Dolichovespula), paper wasps (Polistes) and hornets (Vespa), stinging ants (Solenopsis, Myrmecia, Pachycondyla, and Pogonomyrmex), and bumblebees (Bombus). Insects with importance in specific areas of the world include the Australian tick (Ixodes holocyclus), the kissing bug (Triatoma spp), horseflies (Tabanus spp), and mosquitoes (Aedes, Culex, Anopheles). Reliable access to high quality venom immunotherapy to locally relevant allergens is not available throughout the world. Many current commercially available therapeutic vaccines have deficiencies, are not suitable for, or are unavailable in vast areas of the globe. New products are required to replace products that are unstandardized or inadequate, particularly whole-body extract products. New products are required for insects in which no current treatment options exist. Venom immunotherapy should be promoted throughout the world and the provision thereof be supported by health authorities, regulatory authorities and all sectors of the health care service.
Keywords: allergy and immunology, venoms, Hymenoptera, bee venoms, wasp venoms, insecta, ants hornet, bumblebee, mosquitoes, venom immunotherapy, immunologic desensitization
DiRROS - Published: 23.09.2020; Views: 448; Downloads: 180
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Continuous glucose monitoring use and glucose variability in pre-school children with type 1 diabetes
Klemen Dovč, Kevin Cargnelutti, Anže Šturm, Julij Šelb, Nataša Bratina, Tadej Battelino, 2018

Abstract: Aims. The objective of this nationwide population-based cohort study was to evaluate the correlation between continuous glucose monitoring (CGM) use and glucose variability in pre-schoolers with type 1 diabetes. Methods. We analysed data from the Slovenian National Registry. The primary endpoint was the difference in glucose variability between periods, during which participants were using CGM and periods, during which CGM was not used, over 5 years. Results. A total of 40 children <8 years old were followed for an estimated observational period of 116 patient/years. Mean age at CGM initiation was 3.5 (±1.7) years. Both standard deviation of mean glucose [3.6 mmol/L (3.2–3.9) with CGM and 4.3 mmol/L (3.8–4.7) without CGM, p < 0.001] and coefficient of variation [44.0% (40.4–47.0) with CGM and 46.1% (42.3–49.4) without CGM, p = 0.021] were lower during the periods, when CGM was used. Frequent CGM use (>5 days/week) was associated with a 0.4% [4.4 mmol/mol] reduction in glycated haemoglobin level (7.6% compared to 7.2%, p = 0.047). Conclusions. Our results indicate that the use of CGM was associated with reduced glucose variability during a 5 year follow-up period among pre-schoolers with type 1 diabetes.
Keywords: continuous glucose monitoring, type 1 diabetes, children, insulin therapy
DiRROS - Published: 12.11.2020; Views: 266; Downloads: 141
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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

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
DiRROS - Published: 23.11.2020; Views: 261; Downloads: 99

Routine KIT p.D816V screening identifies clonal mast cell disease in Hymenoptera allergic patients regularly missed using baseline tryptase levels alone
Peter Korošec, Jonathan J. Lyons, Mitja Košnik, Samo Zver, Vladka Čurin-Šerbec, Yihui Liu, Young Hwan Park, Ajda Demšar, Nisera Bajrović, Matevž Škerget, Peter Kopač, Mihaela Zidarn, Renato Eržen, Matija Rijavec, Julij Šelb, 2021

Abstract: Background. Clonal mast cell disorders and elevated BST of unknown cause(s) are associated with severe Hymenoptera venom-triggered anaphylaxis (HVA). However, some individuals with clonal disease have normal BST (<11.4 ng/mL). Objective. To evaluate whether screening for KIT p.D816V in the blood is a useful clinical tool to risk-stratify patients with venom allergy. Methods. We prospectively recruited 374 patients with Hymenoptera allergy and no overt signs of mastocytosis referred to our center in the years 2018-19. KIT p.D816V was determined in the peripheral blood with qPCR and tryptase genotyping was performed by droplet-digital PCR. Results. 351 patients (93.9%) had normal levels of BST and KIT p.D816V was detected in 8% of patients (28/351), predominantly in patients with the most severe Mueller grade IV anaphylaxis (18.2%[24/132] vs 1.8%[4/88 in grade III; 0/131 in other grades] in lower grades; P<0.001). In grade IV patients with normal BST, KIT p.D816V was associated with more severe symptoms including a significantly higher frequency of loss of consciousness (58.3%[14/24] vs 34.3%[37/108]; P=0.03) and absence of skin symptoms (41.7%[10/24] vs 15.7%[17/108]; P=0.004). Among patients with normal BST, KIT p.D816V (OR [95%CI]: 10.25[3.75-36.14]; P<0.0001) was the major risk factor associated with severe HVA. Hereditary [alpha]-tryptasemia (H[alpha]T), due to increased germline copies of TPSAB1 encoding [alpha]-tryptase was the most common cause (65.2%; 15/23) of elevated BST in patients with HVA and together with KIT p.D816V accounted for 90% (20/23) of BST elevations in HVA patients. Conclusion. These results indicate that routine KIT p.D816V screening identifies clonal disease in high-risk HVA patients regularly missed using BST alone.
Keywords: anaphylaxis, venoms, hypersensitivity, hereditary alpha-tryptasemia
DiRROS - Published: 31.03.2021; Views: 73; Downloads: 31

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