Continuous wet denuder measurements of atmospheric nitric and nitrous acids during the 1999 Atlanta Supersite

Two different measurement methods for atmospheric nitric and nitrous acid during the Atlanta Supersite study are described and compared. Both approaches combined wet denuder collection coupled to ion chromatographic analysis. One of these utilized a rotating wet annular denuder maintained indoor with a very dilute Na2CO3 solution as an absorber, operated by the Energieonderzoek Centrum Nederland (ECN), ion chromatography (IC) being conducted with a carbonate eluent system. Data from this instrument was available for a 15 min sample every hour. The other wet denuder was of the parallel plate design and was deployed on the roof of the measurement shelter. This device used dilute H2O2 solution as an absorber and was coupled to an IC operated with a hydroxide eluent. Operated by Texas Tech University (TTU), this instrument provided data with 10 min time resolution. When both instruments were seemingly operating properly, data from TTU and ECN instruments were well correlated, although the peak HNO3 values during high NO2/NOy periods were lower for the TTU instrument. Daily peaks in HNO3, typically ranging in magnitude between 3 and 6 ppbv (7.8 ppbv registered by the ECN instrument on the highest NOy day) were observed. HONO results from both TTU and ECN instruments exhibited strong diurnal variations with nighttime peaks up to ~5 ppbv. Data from the middle of the study period for the two instruments were correlated with a r2 value of 0.78. The relationship was not statistically distinguishable from a 1:1 correspondence. A similar correlation of r2=0.76 was observed for the HNO3 data; in this case the peak concentrations occurring in day tim

Component-resolved diagnosis and beyond: Multivariable regression models to predict severity of hazelnut allergy

Background: Component-resolved diagnosis (CRD) has revealed significant associations between IgE against individual allergens and severity of hazelnut allergy. Less attention has been given to combining them with clinical factors in predicting severity. Aim: To analyze associations between severity and sensitization patterns, patient characteristics and clinical history, and to develop models to improve predictive accuracy. Methods: Patients reporting hazelnut allergy (n = 423) from 12 European cities were tested for IgE against individual hazelnut allergens. Symptoms (reported and during Double-blind placebo-controlled food challenge [DBPCFC]) were categorized in mild, moderate, and severe. Multiple regression models to predict severity were generated from clinical factors and sensitization patterns (CRD- and extract-based). Odds ratios (ORs) and areas under receiver-operating characteristic (ROC) curves (AUCs) were used to evaluate their predictive value. Results: Cor a 9 and 14 were positively (OR 10.5 and 10.1, respectively), and Cor a 1 negatively (OR 0.14) associated with severe symptoms during DBPCFC, with AUCs of 0.70-073. Combining Cor a 1 and 9 improved this to 0.76. A model using a combination of atopic dermatitis (risk), pollen allergy (protection), IgE against Cor a 14 (risk) and walnut (risk) increased the AUC to 0.91. At 92% sensitivity, the specificity was 76.3%, and the positive and negative predictive values 62.2% and 95.7%, respectively. For reported symptoms, associations and generated models proved to be almost identical but weaker. Conclusion: A model combining CRD with clinical background and extract-based serology is superior to CRD alone in assessing the risk of severe reactions to hazelnut, particular in ruling out severe reactions. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd

Hazelnut allergy across Europe dissected molecularly: A EuroPrevall outpatient clinic survey

Background Hazelnut allergy is birch pollen-driven in Northern/Western Europe and lipid transfer protein-driven in Spain and Italy. Little is known about other regions and other allergens. Objective Establishing a molecular map of hazelnut allergy across Europe. Methods In 12 European cities, subjects reporting reactions to hazelnut (n = 731) were evaluated and sensitization to 24 foods, 12 respiratory allergen sources, and latex was tested by using skin prick test and ImmunoCAP. A subset (124 of 731) underwent a double-blind placebo-controlled food challenge to hazelnut. Sera of 423 of 731 subjects were analyzed for IgE against 7 hazelnut allergens and cross-reactive carbohydrate determinants by ImmunoCAP. Results Hazelnut allergy was confirmed in 70% of those undergoing double-blind placebo-controlled food challenges. Birch pollen-driven hazelnut sensitization (Cor a 1) dominated in most cities, except in Reykjavik, Sofia, Athens, and Madrid, where reporting of hazelnut allergy was less frequent anyhow. In Athens, IgE against Cor a 8 dominated and strongly correlated with IgE against walnut, peach, and apple and against Chenopodium, plane tree, and mugwort pollen. Sensitization to seed storage proteins was observed in less than 10%, mainly in children, and correlated with IgE to nuts, seeds, and legumes. IgE to Cor a 12, observed in all cities (10% to 25%), correlated with IgE to nuts, seeds, and pollen. Conclusions In adulthood, the importance of hazelnut sensitization to storage proteins, oleosin (Cor a 12), and Cor a 8 is diluted by the increased role of birch pollen cross-reactivity with Cor a 1. Cor a 8 sensitization in the Mediterranean is probably driven by diet in combination with pollen exposure. Hazelnut oleosin sensitization is prevalent across Europe; however, the clinical relevance remains to be established. © 2015 American Academy of Allergy, Asthma & Immunology

Walnut Allergy Across Europe: Distribution of Allergen Sensitization Patterns and Prediction of Severity

Background: Walnut allergy is common across the globe, but data on the involvement of individual walnut components are scarce. Objectives: To identify geographical differences in walnut component sensitization across Europe, explore cosensitization and cross-reactivity, and assess associations of clinical and serological determinants with severity of walnut allergy. Methods: As part of the EuroPrevall outpatient surveys in 12 European cities, standardized clinical evaluation was conducted in 531 individuals reporting symptoms to walnut, with sensitization to all known walnut components assessed in 202 subjects. Multivariable Lasso regression was applied to investigate predictors for walnut allergy severity. Results: Birch-pollen–related walnut sensitization (Jug r 5) dominated in Northern and Central Europe and lipid transfer protein sensitization (Jug r 3) in Southern Europe. Profilin sensitization (Jug r 7) was prominent throughout Europe. Sensitization to storage proteins (Jug r 1, 2, 4, and 6) was detected in up to 10% of subjects. The walnut components that showed strong correlations with pollen and other foods differed between centers. The combination of determinants best predicting walnut allergy severity were symptoms upon skin contact with walnut, atopic dermatitis (ever), family history of atopic disease, mugwort pollen allergy, sensitization to cat or dog, positive skin prick test result to walnut, and IgE to Jug r 1, 5, 7, or carbohydrate determinants (area under the curve = 0.81; 95% CI, 0.73-0.89). Conclusions: Walnut-allergic subjects across Europe show clear geographical differences in walnut component sensitization and cosensitization patterns. A predictive model combining results from component-based serology testing with results from extract-based testing and information on clinical background allows for good discrimination between mild to moderate and severe walnut allergy. © 2020 The Author