Structural characterization of DynU16, a START/Bet v1-like protein involved in dynemicin biosynthesis

The 1.5 Å resolution crystal structure of DynU16, a protein identified in the dynemicin-biosynthetic gene cluster, is reported. The structure adopts a di-domain helix-grip fold with a uniquely positioned open cavity connecting the domains. The elongated dimensions of the cavity appear to be compatible with the geometry of a linear polyene, suggesting the involvement of DynU16 in the upstream steps of dynemicin biosynthesis.

Conformational Epitope Prediction of Birch Betv 1 and Hazel Cor A1 Towards B-Cells

Background: White birch and hazel allergens, namely Bet v1 and Cor a1 are known allergens, but their allergen specificity is not yet characterized. Objective: To map the antigenic determinants responsible for IgE binding utilizing in silico modelling and docking of the peptides against IgE antibody. Methods: The antigen sequences were cut into peptides are docked against the IgE antibody and those with the highest docking scores are further studied for the bond interactions. The overlapping sequences of the high score peptides are observed in the whole antigen model to predict their position. The residues at bond interactions also been reported for these overlapping peptide sequences. Results: The validation is done by antigen-antibody docking studies to confirm the predicted epitope. 25% of the world population suffers from allergic rhinitis and 15% of them develop asthma. Conclusion: Negative binding energies of the studied pollen allergens with IgE confirm their allergenicity. Based on the results of overlapping peptides PF 3,4 and PF 16,17 to play a key role in the allergenic response of white birch and Common hazel.

Changes in qualitative and quantitative traits of birch (Betula pendula) pollen allergenic proteins in relation to the pollution contamination

Birch (Betula pendula) pollen causes inhalant allergy in about 20% of human population in Europe, most of which is sensitive to the main birch allergen, Bet v1. The aim of the study was to find out (i) whether and how the analysed birch individuals differ in regard to composition of individual subunits of pollen proteins and to protein content in these subunits; (ii) whether the level of particulate matter relates to concentration of Bet v1 allergen. Study was performed in Southern Poland, in 2017–2019. Pollen material was collected at 20 sites, of highly or less polluted areas. Protein composition was analysed by SDS-PAGE, while the concentration of Bet v1 was evaluated by ELISA. The obtained results were estimated at the background of the particulate matter (PM10) level and the birch pollen seasons in Kraków. The electrophoregrams of pollen samples collected at different sites showed huge differences in staining intensities of individual protein subunits, also among important birch allergens: Bet v1, Bet v2, Bet v6 and Bet v7. The level of Bet v1 was significantly higher in the pollen samples collected at the more polluted sites. While the birch pollen allergenic potential is determined, the both pollen exposure and the content of the main allergenic components should be considered, as factors causing immunological response and clinical symptoms manifestation in sensitive individuals.

Hazelnut Allergy

Background and Objectives: Hazelnuts are frequently involved in IgE-mediated reactions and represent the main culprit of nut allergy in Europe. The clinical presentation varies from mild symptoms limited to the oropharynx [oral allergy syndrome (OAS)], due to the cross-reaction with homologues in pollen allergens and more severe events caused by the primary sensitization to highly stable molecules contained in hazelnuts. The aim of this review is to summarize the most relevant concepts in the field of hazelnut allergy and to provide a practical approach useful in the clinical practice Materials and Methods: References were identified by PubMed searches dating from January 2000 up to November 2020 using the search terms: “component resolved diagnosis” and “Hazelnut allergy. Results: The storage proteins Cor a 9 and Cor a 14 resulted highly specific for primary hazelnut allergy and strongly associated with severe reactions, while the cross reactive Cor a 1, an homolog of the birch Bet v1, were related to OAS. Any cut-off has shown a specificity and sensitivity pattern as high as to replace the oral food challenge (OFC), which still remains the gold standard in the diagnosis of hazelnut allergy. To date there is still no definitive treatment. Hazelnut free-diet and treatment of symptoms with emergency management, including the prescription of auto-injective epinephrine, still represent the main approach. Oral allergen immunotherapy (AIT) appears a promising therapeutic strategy and the definition of individual clinical threshold would be useful for sensitized individuals, caregivers, and physicians to reduce social limitation, anxiety, and better manage food allergy. Conclusions: An accurate diagnostic work-up including clinical history, in vivo and in vitro test including component resolved diagnosis and OFC are essential to confirm the diagnosis, to assess the risk of a severe reaction, and to prescribe an adequate diet and treatment.

Oral allergy syndrome and angioedema in patients with birch allergen sensitization: are there any high risks?

Aim: to study the sensitization profile in patients with sensitivity to Bet v1 allergen who have clinically significant respiratory symptoms of pollinosis during the birch flowering season, oral allergy syndrome (OAS), and angioedema to nuts and stone fruits. Patients and Methods: a prospective open-label study included 40 children (average age 7.52±0.64), 26 (65%) boys and 14 (35%) girls. All children had sensitization to the birch major allergen (Bet v1), symptoms of respiratory allergy during the birch flowering season, manifestations of OAS with angioedema in combination with hives or without it after eating fruits of Rosaceae family/nuts/peanuts. Children underwent general clinical and allergy researches, determination of total IgE and eosinophil cationic protein. By the method of component-resolved diagnosis of allergy (ISAC-112, ImmunoCAP), a comprehensive allergology examination for 112 allergen molecules was performed for each child. Results: the children of the study group were found to have increased values of total IgE (256.66±40.45 IU/mL) and eosinophil cationic protein (67.22±8.67 ng/mL). It was found that 57.5% of children were sensitized to tree nut storage proteins (rJug r1, rJug r2, NCoR a9, rAna o2, rBer e1), and some patients (27.5%) had increased specific IgE to non-specific lipid-transfer proteins (npLTPs) (rPru p3, NCoR a8, rAra h9, rJug r3). Antibodies to peanut storage proteins (rAra h1, rAra h2, rAra h3, rAra h6) were in 22.5% of children in the study group. Conclusion: the component-resolved diagnosis of allergy allows to determine the sensitization profile of patients. Sensitization detection to storage proteins and/or nsLTPs of nuts, peanuts and fruits is a predictor of possible severe allergic reactions. The exclusion of these products, both raw and heat-treated, reduces the number of severe acute allergic reactions in patients and prevents possible fatal outcomes. KEYWORDS: oral allergy syndrome, angioedema, children, birch, sensitization to Bet v1 allergen, storage proteins, nsLTPs. FOR CITATION: Lepeshkova T.S., Beltyukov E.K., Tsarkova S.A., Naumova V.V. Oral allergy syndrome and angioedema in patients with birch allergen sensitization: are there any high risks? Russian Medical Inquiry. 2021;5(1):21–24. DOI: 10.32364/2587-6821-2021-5-1-21-24.

The Interaction between Antioxidants Content and Allergenic Potency of Different Raspberry Cultivars

Food allergies are a very serious problem among consumers. The most common food allergies involve animal products, but they can also involve fruits such as berries. We aimed to determine whether organic farming is useful for the production of high-quality and safe fruits. Three varieties of raspberries ‘Laszka’, ‘Glen Ample’ and ‘Polka’ from organic and conventional production (neighboring farms) were collected over the two years of the experiment. Quantitative and qualitative analysis of phenolic compounds was carried out, and the content of Bet v1 and profilin was determined. The organic raspberries contained a lower level of phenolic compounds, especially anthocyanins. Conventional fruits were characterized by a higher allergenic potency than organic ones. We found a strong link between their anthocyanin content and the allergy status of conventional raspberry fruits. Therefore, organically produced raspberries are safer for consumers.

Evaluation of the Potential Allergenicity of Strawberries in Response to Different Farming Practices

Fruit allergies are a large problem today. Many consumers suffer from food allergies or intolerances. The method of food production has a major impact on its quality. In fruit and vegetable production, three different farming systems are mainly found: conventional, integrated pest management and organic production. The latter is considered the best in terms of fruits and vegetables safety and high quality. The present experiment was performed to demonstrate the effect of the strawberry production method on its allergenic properties and flavonoid content. The strawberry ‘Honeoye’ cv. was used for the study. Fruits from the three cultivation systems, organic, conventional and integrated, were tested for their content of biologically active compounds and their potential allergenicity. The results obtained indicate that the strawberries from the organic system were the safest because they contained the lowest levels of Bet v1 and profilin in comparison with the fruits from the integrated and conventional systems.

Potential Differences between Local and Systemic Allergic Rhinitis Induced by Birch Pollen

<b><i>Introduction:</i></b> Different endotypes of rhinitis are known, but its pathomechanism has not been conclusively established. For example, the precise difference between systemic allergic rhinitis (SAR) and local allergic rhinitis (LAR) is still being checked. Comparison of patients with LAR and with allergies to birch of those with intermittent allergic rhinitis, same allergy, or with non-allergic rhinitis (NAR) was the purpose of this study. <b><i>Methods:</i></b> Twenty-six patients with LAR, 18 with SAR and allergy to birch, and 21 with NAR were included. Patients who met the inclusion criteria were selected to undergo the following procedures at baseline: medical examinations, nasal provocation test (NPT), detection of nasal-specific IgE to birch as well as basophil activation test (BAT). All immunological parameters were detected before and after NPT. <b><i>Results:</i></b> Concentration of nasal IgE to Bet v1 increased comparably in the LAR and SAR groups after NPT to birch as follows: in 21 (81%) patients with LAR, 14 (78%) with SAR, and in everyone in the NAR group. Serum concentration of allergen-specific IgE to Bet v1 increased significantly from a median of 20.7 (25–75% interval: 11.2–35.6) IU/mL to 29.9 (13.6–44.1) (<i>p</i> = 0.028) after NPT in patients with SAR. Allergen-specific IgE to Bet v1 was absent in all patients with LAR and NAR before and after NPT. BAT with Bet v1 was positive in 22 (85%) patients with LAR, in 14 (78%) with SAR, and 2 (9.5%) with NAR. <b><i>Conclusion:</i></b> These obtained data suggest there are no potential mechanisms that could explain LAR compared to SAR.