Background: The nature of epitopes on Bet v 1 recognized by natural IgG antibodies of birch pollen allergic patients and birch pollen‐exposed but non‐sensitized subjects has not been studied in detail.Objective: To investigate IgE and IgG recognition of Bet v 1 and to study the effects of natural Bet v 1‐specific IgG antibodies on IgE recognition of Bet v 1 and Bet v 1‐induced basophil activation.Methods: Sera from birch pollen allergic patients (BPA, n = 76), allergic patients without birch pollen allergy (NBPA, n = 40) and non‐allergic individuals (NA, n = 48) were tested for IgE, IgG as well as IgG₁ and IgG₄ reactivity to folded recombinant Bet v 1, two unfolded recombinant Bet v 1 fragments comprising the N‐terminal (F1) and C‐terminal half of Bet v 1 (F2) and unfolded peptides spanning the corresponding sequences of Bet v 1 and the apple allergen Mal d 1 by ELISA or micro‐array analysis. The ability of Bet v 1‐specific serum antibodies from non‐allergic subjects to inhibit allergic patients IgE or IgG binding to rBet v 1 or to unfolded Bet v 1‐derivatives was assessed by competition ELISAs. Furthermore, the ability of serum antibodies from allergic and non‐allergic subjects to modulate Bet v 1‐induced basophil activation was investigated using rat basophilic leukaemia cells expressing the human FcεRI which had been loaded with IgE from BPA patients.Results: IgE antibodies from BPA patients react almost exclusively with conformational epitopes whereas IgG, IgG₁ and IgG₄ antibodies from BPA, NBPA and NA subjects recognize mainly unfolded and sequential epitopes. IgG competition studies show that IgG specific for unfolded/sequential Bet v 1 epitopes is not inhibited by folded Bet v 1 and hence the latter seem to represent cryptic epitopes. IgG reactivity to Bet v 1 peptides did not correlate with IgG reactivity to the corresponding Mal d 1 peptides and therefore does not seem to be a result of primary sensitization to PR10 allergen‐containing food. Natural Bet v 1‐specific IgG antibodies inhibited IgE binding to Bet v 1 only poorly and could even enhance Bet v 1‐specific basophil activation.Conclusion: IgE and IgG antibodies from BPA patients and birch pollen‐exposed non‐sensitized subjects recognize different epitopes. These findings explain why natural allergen‐specific IgG do not protect against allergic symptoms and suggest that allergen‐specific IgE and IgG have different clonal origin.

BACKGROUND: Skin epidermal barrier impairment in patients with atopic dermatitis facilitates percutaneous penetration of allergens and leads to persistent skin inflammation in sensitized patients and even primary sensitization to the allergens. We hypothesized that the use of skincare products that restore the structure of the skin barrier may positively affect the disease course in patients with atopic dermatitis and pollen sensitization during the pollen season. AIMS: This study aimed to investigate the clinical efficacy and safety of La Roche Posay formulas, i.e., Lipikar Syndet and Lipikar Baume AP+M, in the prevention of atopic dermatitis exacerbations in children and adults sensitized to different pollen allergens during the pollination season. MATERIALS AND METHODS: Sixty patients aged 560 years with a clinical history of mild-to-moderate atopic dermatitis sensitized to different pollen allergens were enrolled in a single-center, simple, open, prospective comparative study, and they were divided into two groups. The main group used Lipikar Syndet and Baume AP+M daily together with standard atopic dermatitis treatment for 28 days during the pollen season of their clinically significant allergens. The control group received only standard therapy without any use of moisturizers. The study required three visits. At each visit, the severity of atopic dermatitis (SCORing atopic dermatitis [SCORAD] index), quality of life (Dermatology Life Quality Index/and Childrens Dermatology Life Quality Index), pruritus intensity (numerical rating scale), and corneometry were assessed. SCORAD changes were considered the primary endpoint of the study. RESULTS: A significant decrease in SCORAD in the main group was registered by day 14 of the study (p 0.0001), whereas no significant changes in the SCORAD index were noted in the control group even by day 28. The SCORAD index in the main group was significantly lower than that in the control group (p=0.005) by day 28. For the secondary endpoints, the quality of life significantly improved by day 28 (p=0.0005), the intensity of pruritus significantly decreased (p 0.0001), and the level of skin hydration increased (p 0.0001) by day 14 in the main group compared with those in the control group. No adverse events were reported during the study. CONCLUSIONS: Daily use of Lipikar Syndet and Lipikar Baume AP+M by patients with atopic dermatitis and pollen allergy during the pollen season significantly improved the atopic dermatitis course, reducing skin itching and improving skin hydration and patients quality of life. The use of these skincare products together with atopic dermatitis therapy helped reduce atopic dermatitis severity associated with direct skin contact with pollen allergens. This indicates a protective effect of Lipikar skincare products on the epidermal barrier function.

BACKGROUND: Birch pollen allergy is widespread and is the main allergic disease in Russia. Cross-reactive food allergy, often found in patients with birch pollen allergy, is an underestimated problem that complicates the course of pollinosis and requires further study to improve the quality of diagnosis and personalized recommendations for such patients. AIM: To study the features of the molecular sensitization profile of adult patients with birch pollen allergy and cross-reactive food allergy to PR-10 proteins. MATERIALS AND METHODS: Twenty-five adult patients with confirmed birch pollen allergy, with or without cross-reactive food allergy, were included in an open single-center interventional prospective controlled nonrandomized study. Specific IgE to 112 allergens was determined by multiplex analysis using ImmunoCAP ISAC (ThermoFisher, Sweden). Patients with cross-reactive food allergy completed a validated questionnaire on cross-reactive food allergy symptoms and causative allergens. The primary endpoint of the study was the assessment of the sensitization profile to Bet v 1 and PR-10 proteins (Mal d 1, Ara h 8, Cor a 1.0101, Cor a 1.0401, Act d 8, Api g 1, Pru p 1, and Gly m 4) and the clinical characteristics of the sensitized patients. The secondary endpoint was the comparison of patients with and without cross-reactive food allergy and the evaluation of how sensitization to Bet v 1 and PR-10 homologs can affect clinical manifestations of cross-reactive food allergy in patients. RESULTS: The study included 25 patients aged 18–55 years, from which two comparable groups were formed: group 1 consisted of 13 patients with cross-reactive food allergy symptoms and group 2 (without cross-reactive food allergy) consisted of 12 patients who had never experienced cross-reactive food allergy symptoms. Analysis of the sensitization profile to PR-10 allergens revealed similar patterns in both groups; however, sIgE concentrations to all allergens were significantly higher in group 1. A strong correlation was found between the number of triggering products and total IgE level with PR-10 proteins (r=0.81; p=0.001). The severity of cross-reactive food allergy symptoms correlated with the total level of IgE to PR-10 proteins (r=0.97; p 0.0001). The cutoff level for total sIgE to food PR-10 proteins, equal to 70 ISU-E, allowed us to distinguish patients with only oral allergic syndrome from those with systemic manifestations of cross-reactive food allergy. CONCLUSION: The results of the study are applicable in clinical practice and have prognostic value in determining the severity of cross-reactive food allergy.

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