Tolerance development in cow's milk-allergic children receiving amino acid-based formula with synbiotics: 36-Months follow-up of a randomized controlled trial (PRESTO Study)

The objective of the present study is to assess the rates of acquired tolerance to cow's milk (CM) after 36 months in subjects who consumed amino acid-based formula with synbiotics (AAF-S) or amino acid-based formula without synbiotics (AAF) during a 1-year intervention period in early life as part of the PRESTO study (Netherlands Trial Register number NTR3725). Differences in CM tolerance development between groups were analysed using a logistic regression model. Results show that the proportion of subjects (mean [±SD] age, 3.8 ± 0.27 years) who developed CM tolerance after 36 months was similar in the group receiving AAF-S (47/60 [78%]) and in the group receiving AAF (49/66 [74%]) (p = 0.253), that is, figures comparable to natural outgrowth of CM allergy. Our data suggest that the consumption of AAF and absence of exposure to CM peptides do not slow down CM tolerance acquisition.

Diagnosis and treatment of Hymenoptera venom allergy: S2k Guideline of the German Society of Allergology and Clinical Immunology (DGAKI) in collaboration with the Arbeitsgemeinschaft für Berufs- und Umweltdermatologie e.V. (ABD), the Medical Association of German Allergologists (AeDA), the German Society of Dermatology (DDG), the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery (DGHNOKC), the German Society of Pediatrics and Adolescent Medicine (DGKJ), the Society for Pediatric Allergy and Environmental Medicine (GPA), German Respiratory Society (DGP), and the Austrian Society for Allergy and Immunology (ÖGAI)

Hymenoptera venom (HV) is injected into the skin during a sting by Hymenoptera such as bees or wasps. Some components of HV are potential allergens and can cause large local and/or systemic allergic reactions (SAR) in sensitized individuals. During their lifetime, ~ 3% of the general population will develop SAR following a Hymenoptera sting. This guideline presents the diagnostic and therapeutic approach to SAR following Hymenoptera stings. Symptomatic therapy is usually required after a severe local reaction, but specific diagnosis or allergen immunotherapy (AIT) with HV (VIT) is not necessary. When taking a patient's medical history after SAR, clinicians should discuss possible risk factors for more frequent stings and more severe anaphylactic reactions. The most important risk factors for more severe SAR are mast cell disease and, especially in children, uncontrolled asthma. Therefore, if the SAR extends beyond the skin (according to the Ring and Messmer classification: grade > I), the baseline serum tryptase concentration shall be measured and the skin shall be examined for possible mastocytosis. The medical history should also include questions specific to asthma symptoms. To demonstrate sensitization to HV, allergists shall determine concentrations of specific IgE antibodies (sIgE) to bee and/or vespid venoms, their constituents and other venoms as appropriate. If the results are negative less than 2 weeks after the sting, the tests shall be repeated (at least 4 - 6 weeks after the sting). If only sIgE to the total venom extracts have been determined, if there is double sensitization, or if the results are implausible, allergists shall determine sIgE to the different venom components. Skin testing may be omitted if in-vitro methods have provided a definitive diagnosis. If neither laboratory diagnosis nor skin testing has led to conclusive results, additional cellular testing can be performed. Therapy for HV allergy includes prophylaxis of reexposure, patient self treatment measures (including use of rescue medication) in the event of re-stings, and VIT. Following a grade I SAR and in the absence of other risk factors for repeated sting exposure or more severe anaphylaxis, it is not necessary to prescribe an adrenaline auto-injector (AAI) or to administer VIT. Under certain conditions, VIT can be administered even in the presence of previous grade I anaphylaxis, e.g., if there are additional risk factors or if quality of life would be reduced without VIT. Physicians should be aware of the contraindications to VIT, although they can be overridden in justified individual cases after weighing benefits and risks. The use of β-blockers and ACE inhibitors is not a contraindication to VIT. Patients should be informed about possible interactions. For VIT, the venom extract shall be used that, according to the patient's history and the results of the allergy diagnostics, was the trigger of the disease. If, in the case of double sensitization and an unclear history regarding the trigger, it is not possible to determine the culprit venom even with additional diagnostic procedures, VIT shall be performed with both venom extracts. The standard maintenance dose of VIT is 100 µg HV. In adult patients with bee venom allergy and an increased risk of sting exposure or particularly severe anaphylaxis, a maintenance dose of 200 µg can be considered from the start of VIT. Administration of a non-sedating H1-blocking antihistamine can be considered to reduce side effects. The maintenance dose should be given at 4-weekly intervals during the first year and, following the manufacturer's instructions, every 5 - 6 weeks from the second year, depending on the preparation used; if a depot preparation is used, the interval can be extended to 8 weeks from the third year onwards. If significant recurrent systemic reactions occur during VIT, clinicians shall identify and as possible eliminate co-factors that promote these reactions. If this is not possible or if there are no such co-factors, if prophylactic administration of an H1-blocking antihistamine is not effective, and if a higher dose of VIT has not led to tolerability of VIT, physicians should should consider additional treatment with an anti IgE antibody such as omalizumab as off lable use. For practical reasons, only a small number of patients are able to undergo sting challenge tests to check the success of the therapy, which requires in-hospital monitoring and emergency standby. To perform such a provocation test, patients must have tolerated VIT at the planned maintenance dose. In the event of treatment failure while on treatment with an ACE inhibitor, physicians should consider discontinuing the ACE inhibitor. In the absence of tolerance induction, physicians shall increase the maintenance dose (200 µg to a maximum of 400 µg in adults, maximum of 200 µg HV in children). If increasing the maintenance dose does not provide adequate protection and there are risk factors for a severe anaphylactic reaction, physicians should consider a co-medication based on an anti-IgE antibody (omalizumab; off-label use) during the insect flight season. In patients without specific risk factors, VIT can be discontinued after 3 - 5 years if maintenance therapy has been tolerated without recurrent anaphylactic events. Prolonged or permanent VIT can be considered in patients with mastocytosis, a history of cardiovascular or respiratory arrest due to Hymenoptera sting (severity grade IV), or other specific constellations associated with an increased individual risk of recurrent and/or severe SAR (e.g., hereditary α-tryptasemia). In cases of strongly increased, unavoidable insect exposure, adults may receive VIT until the end of intense contact. The prescription of an AAI can be omitted in patients with a history of SAR grade I and II when the maintenance dose of VIT has been reached and tolerated, provided that there are no additional risk factors. The same holds true once the VIT has been terminated after the regular treatment period. Patients with a history of SAR grade ≥ III reaction, or grade II reaction combined with additional factors that increase the risk of non response or repeated severe sting reactions, should carry an emergency kit, including an AAI, during VIT and after regular termination of the VIT.

Guideline for allergological diagnosis of drug hypersensitivity reactions: S2k Guideline of the German Society for Allergology and Clinical Immunology (DGAKI) in cooperation with the German Dermatological Society (DDG), the Association of German Allergologists (ÄDA), the German Society for Pediatric Allergology (GPA), the German Contact Dermatitis Research Group (DKG), the German Society for Pneumology (DGP), the German Society of Otorhinolaryngology, Head and Neck Surgery, the Austrian Society of Allergology and Immunology (ÖGAI), the Austrian Society of Dermatology and Venereology (ÖGDV), the German Academy of Allergology and Environmental Medicine (DAAU), and the German Documentation Center for Severe Skin Reactions (dZh)

Not available.

Food-Induced Anaphylaxis: Data From the European Anaphylaxis Registry

BACKGROUND

Food is one of the most common elicitors of anaphylaxis, with an increasing incidence over recent years.

OBJECTIVES

To characterize elicitor-specific phenotypes and identify factors enhancing the risk or severity of food-induced anaphylaxis (FIA).

METHODS

We analyzed data from the European Anaphylaxis Registry applying an age- and sex-matched analysis of associations (Cramer's V) for single food triggers and calculated odds ratios (ORs) for severe FIA.

RESULTS

We identified 3,427 cases of confirmed FIA showing an age-dependent elicitor ranking (for children: peanut, cow's milk, cashew, and hen's egg; and for adults: wheat flour, shellfish, hazelnut, and soy). The age- and sex-matched analysis revealed defined symptom patterns for wheat and cashew. Wheat-induced anaphylaxis was more frequently associated with cardiovascular symptoms (75.7%; Cramer's V = 0.28) and cashew-induced anaphylaxis with gastrointestinal symptoms (73.9%; Cramer's V = 0.20). Furthermore, concomitant atopic dermatitis was slightly associated with anaphylaxis to hen's egg (Cramer's V = 0.19) and exercise was strongly associated with anaphylaxis to wheat (Cramer's V = 0.56). Additional factors influencing the severity were alcohol intake in wheat anaphylaxis (OR = 3.23; CI, 1.31-8.83) and exercise in peanut anaphylaxis (OR = 1.78; CI, 1.09-2.95).

CONCLUSIONS

Our data show that FIA is age-dependent. In adults, the range of elicitors inducing FIA is broader. For some elicitors, the severity of FIA seems to be related to the elicitor. These data require confirmation in future studies considering a clear differentiation between augmentation and risk factors in FIA.

The role of online symptom questionnaires to support the diagnosis of cow's milk allergy in children for healthcare professionals - A Delphi consensus study

BACKGROUND

Cow's milk allergy (CMA) is one of the most common food allergies world-wide. The emergence of online CMA symptom questionnaires, aimed at parents and/or healthcare professionals (HCP), may raise awareness about the possible diagnosis of CMA, but also increases the risk for overdiagnosis leading to unnecessary dietary restriction impacting on growth and nutrition. This publication sets out to establish the availability of these CMA symptom questionnaires and critically assesses the development and validity.

METHODS

Thirteen HCP working in the field of CMA, from different countries, were recruited to participate. A combination of a Pubmed and CINAHL literature and online review using the Google search engine in English language was used. Symptoms in the questionnaires were assessed, using the European Academy for Allergy and Clinical Immunology guidelines for food allergy. Following the assessment of both the questionnaires and literature, the authors followed the modified Delphi approach to generate consensus statements.

RESULTS

Six hundred and fifty-one publications were identified, of which 29 were suitable for inclusion, with 26 being associated with the Cow's Milk-Related Symptoms Score. The online search yielded 10 available questionnaires: 7/10 were sponsored by formula milk companies and 7/10 were aimed at parents and three at HCP. Following the assessment of data, 19 statements were generated in two rounds of anonymous voting reaching 100% agreement.

CONCLUSIONS

Online CMA questionnaires, available to parents and HCP's, are varied in symptoms, and most were not validated. The overarching consensus generated from authors is that these questionnaires should not be used without the involvement of HCP.

Cow's milk and hen's egg anaphylaxis: A comprehensive data analysis from the European Anaphylaxis Registry

BACKGROUND

Cow's milk (CM) and hen's egg (HE) are leading triggers of anaphylaxis in early childhood. The aim of this study was to identify clinical phenotypes and therapeutic measures for CM anaphylaxis (CMA) compared to HE anaphylaxis (HEA) in children up to 12 years of age, based on a large pan-European dataset from the European Anaphylaxis Registry.

METHODS

Data from 2007 to 2020 on clinical phenotypes and treatment from 10 European countries, as well as Brazil, were analysed. The two-step cluster analysis was used to identify the most frequent phenotypes. For each trigger, three clusters were extracted based on sex, age, and existence of symptoms in four vitally important systems.

RESULTS

Altogether 284 children with CMA and 200 children with HEA were identified. They were characterised as male (69% vs. 64%), infants (65% vs. 61%), with a most frequent grade III of Ring&Messmer classification (62% vs. 64%), in CMA versus HEA, respectively. Respiratory symptoms occurred more often in CMA (91% vs. 83%, p = 0.010), especially in infants (89% vs. 79%, p = 0.008). Cardiovascular symptoms were less frequent in CMA (30% vs. 44%, p = 0.002), in both infants (33% vs. 46%, p = 0.027), and older children (25% vs. 42%, p = 0.021). The clusters extracted in the CMA group were characterised as: (1) mild dermal infants with severe GI (40%), 2. severe dermal (35%), 3. respiratory (25%). While in HEA group: 1. infants with severe GI and/or reduction of alertness (40%), (2) conjunctival (16%), (3) mild GI without conjunctivitis (44%). The severity of the reaction was independent from the amount of ingested allergen protein, regardless of trigger. The first-line adrenaline application differed between the countries (0%-92%, as well as the reasons for not administering adrenaline, p < 0.001).

CONCLUSIONS

Despite the similarity of their age, sex, and severity grade, the clinical profiles differed between the CMA and HEA children. Adrenaline was underused, and its administration was country dependent. Further studies are needed to assess to what extent the differences in the clinical profiles are related to matrix and/or absorption effects, and/or the allergen itself.

Efficacy and safety of peanut epicutaneous immunotherapy in patients with atopic comorbidities

Background

Co-occurring atopic conditions are common in children with peanut allergy. As such, it is important to examine the safety and efficacy of epicutaneous immunotherapy with Viaskin Peanut 250 μg patch (VP250) in peanut-allergic children with these conditions.

Objective

We sought to compare efficacy and safety of VP250 versus placebo in peanut-allergic children with/without ongoing atopic conditions at baseline, including asthma, atopic dermatitis/eczema, or concomitant food allergy.

Methods

A subgroup analysis of peanut-allergic children aged 4 to 11 years enrolled in PEPITES (12 months) and REALISE (6 months) randomized, placebo-controlled, phase 3 trials was conducted. The efficacy outcome measure was the difference in prespecified responder rate between placebo and VP250 groups at month 12 based on eliciting dose of peanut protein using double-blind, placebo-controlled food challenge in PEPITES. Safety profiles were evaluated by baseline concomitant disease subgroup in all randomized subjects who received 1 or more dose of the study drug in PEPITES and REALISE pooled data.

Results

Responder rates were significantly (P < .05, all comparisons) greater with VP250 compared with placebo treatment regardless of whether subjects had other atopic conditions. Safety and tolerability profiles were generally similar across subgroups, with no new safety concerns detected. A trend for both higher responder rates and rates of local reactions was observed in subjects with baseline atopic dermatitis versus those without. In subjects with concomitant food allergy at baseline, higher rates of treatment-emergent adverse events, but not study discontinuations or overall rates of anaphylaxis, were observed.

Conclusions

The results support the safety and efficacy of VP250 for treating peanut-allergic children with or without concomitant atopic conditions.

Ana o 3 sIgE and diagnostic algorithms reduce cost of cashew allergy diagnosis in children compared with skin prick test: A cost comparison analysis

BACKGROUND

In the absence of a clear clinical history of reaction, diagnosis of cashew allergy using skin prick tests (SPT) or cashew-specific IgE requires a high number of oral food challenges (OFC). By using Ana o 3 sIgE alone, or a two-step diagnostic algorithm using cashew sIgE followed by Ana o 3 sIgE, there is a reduced need for OFC. We aimed to perform a cost comparison for both of these approaches compared with cashew SPT alone.

METHODS

Pooled individual-level data from 6 studies were used to determine diagnostic accuracy and OFC rate. Two studies used cashew SPT (n = 567, 198 allergic), with 95% positive and negative predictive values of ≥12 mm and <3 mm. Four studies were included in the pathways for Ana o 3 sIgE alone or a 2-step algorithm incorporating cashew and Ana o 3 sIgE (n = 271, 156 allergic). Cut-offs used were ≥8.5kUA/L and ≤0.1kUA/L for cashew sIgE and ≥0.35kUA/L and ≤0.1kUA/L for Ana o 3 sIgE. Costs were constructed based on unit prices from hospital inpatient admissions, expenses incurred by families, individual patient data on allergic reaction types and rates, and adrenaline autoinjector carriage, applying a health system perspective.

RESULTS

Modeled data through the Ana o 3 pathway resulted in a 46.43% cost reduction (€307,406/1000 patients) compared with using cashew SPT alone (€573,854/1000 patients). The 2-step algorithm resulted in a 44.94% cost reduction compared with SPT alone (€315,952.82/1000 patients). Both the Ana o 3 pathway and 2-step algorithm resulted in a 79%-80% reduction in OFCs compared with SPT.

CONCLUSIONS

Using Ana o 3 as a standalone test for cashew allergy diagnosis or a 2-step algorithm incorporating cashew sIgE and Ana o 3 sIgE is accurate and results in a large reduction in both OFCs and health system costs compared with cashew SPT alone.

InSight Pressure Data Recalibration, and Its Application to the Study of Long-Term Pressure Changes on Mars

Observations of the South Polar Residual Cap suggest a possible erosion of the cap, leading to an increase of the global mass of the atmosphere. We test this assumption by making the first comparison between Viking 1 and InSight surface pressure data, which were recorded 40 years apart. Such a comparison also allows us to determine changes in the dynamics of the seasonal ice caps between these two periods. To do so, we first had to recalibrate the InSight pressure data because of their unexpected sensitivity to the sensor temperature. Then, we had to design a procedure to compare distant pressure measurements. We propose two surface pressure interpolation methods at the local and global scale to do the comparison. The comparison of Viking and InSight seasonal surface pressure variations does not show changes larger than ±8 Pa in the CO₂ cycle. Such conclusions are supported by an analysis of Mars Science Laboratory (MSL) pressure data. Further comparisons with images of the south seasonal cap taken by the Viking 2 orbiter and MARCI camera do not display significant changes in the dynamics of this cap over a 40 year period. Only a possible larger extension of the North Cap after the global storm of MY 34 is observed, but the physical mechanisms behind this anomaly are not well determined. Finally, the first comparison of MSL and InSight pressure data suggests a pressure deficit at Gale crater during southern summer, possibly resulting from a large presence of dust suspended within the crater.

Organ-specific symptom patterns during oral food challenge in children with peanut and tree nut allergy

BACKGROUND

Peanut and tree nut allergies are common in childhood and often severe in nature. The clinical picture shows a wide variety of symptoms.

OBJECTIVE

To analyze the distribution of clinical symptoms and severity during oral food challenges (OFC) in children.

METHODS

Analysis of 1.013 prospectively recorded, positive OFCs with peanut (n = 607), hazelnut (n = 266), walnut (n = 97), and cashew (n = 43). Symptoms were categorized as immediate-type skin, gastrointestinal, upper and lower respiratory, cardiovascular symptoms, and eczema exacerbation. Symptom severity and treatment were recorded.

RESULTS

Skin symptoms presented in 78%, followed by gastrointestinal (47%), upper (42%), and lower respiratory symptoms (32%). Cardiovascular symptoms presented in 6%. In three-quarter of the reactions, more than one organ was involved. Importantly, severe reactions occurred at every dose level. Peanut- and cashew-allergic patients had a higher relative risk of gastrointestinal symptoms compared with hazelnut- and walnut-allergic patients. Patients without vomiting had a 1.7 times higher risk developing immediate-type skin and/or lower respiratory symptoms. Three-quarter of the patients ever had eczema but worsening presented in only 10.5% of the OFCs. In patients with multiple food allergies, organs involved, eliciting dose and severity differed between allergens.

CONCLUSION

Although comparisons between allergen groups with different clinical history, severity, comorbidities and laboratory data are difficult and might contain bias, our data confirm the high allergenic potential of peanut and tree nuts. The rare occurrence of eczema worsening emphasizes that avoidance diets of peanuts and tree nuts to cure eczema seem to be unnecessary and may hamper tolerance maintenance.

Different Patterns of Foods Triggering FPIES in Germany

BACKGROUND

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated gastrointestinal food allergy mainly affecting infants and young children. Allergic FPIES reactions differ from IgE-mediated food allergies, for example, regarding elicitors and clinical course.

OBJECTIVE

The aim of our study was to describe causative agents and development of tolerance in German children with FPIES.

METHODS

We conducted a retrospective survey on children with FPIES from 14 centers in Germany assessing a 6-year period.

RESULTS

We analyzed 142 patients with 190 FPIES reactions, 130 of which met acute FPIES criteria and 60 were defined as chronic FPIES. The most frequent eliciting food for acute FPIES was cow's milk, followed by fish, vegetables (eg, potato, pumpkin), meats (eg, beef), and grains. A total of 119 children reacted to 1 food only, 16 children to 2 or 3 foods, and 7 children to ≥4 foods. In chronic FPIES, all but 4 exclusively breastfed infants reacted to cow's milk feeding. IgE sensitization to the triggering food was found in 21 of 152 (14%) cases. Two children developed additional IgE-mediated symptoms upon a food challenge. Time to proof of tolerance was shortest in cow's milk-induced FPIES, and it was shorter in chronic than in acute FPIES.

CONCLUSION

In our national survey, we identified triggers for acute FPIES that partially differ from those reported internationally. Mainly foods introduced early in infant nutrition triggered acute reactions. Time to proven tolerance was shown to be contingent on FPIES symptomatology and on the triggering food. These data should be considered regarding nutritional advice for infants with FPIES.

Genome-wide analysis of mitochondrial DNA copy number reveals loci implicated in nucleotide metabolism, platelet activation, and megakaryocyte proliferation

Mitochondrial DNA copy number (mtDNA-CN) measured from blood specimens is a minimally invasive marker of mitochondrial function that exhibits both inter-individual and intercellular variation. To identify genes involved in regulating mitochondrial function, we performed a genome-wide association study (GWAS) in 465,809 White individuals from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium and the UK Biobank (UKB). We identified 133 SNPs with statistically significant, independent effects associated with mtDNA-CN across 100 loci. A combination of fine-mapping, variant annotation, and co-localization analyses was used to prioritize genes within each of the 133 independent sites. Putative causal genes were enriched for known mitochondrial DNA depletion syndromes (p = 3.09 × 10-15) and the gene ontology (GO) terms for mtDNA metabolism (p = 1.43 × 10-8) and mtDNA replication (p = 1.2 × 10-7). A clustering approach leveraged pleiotropy between mtDNA-CN associated SNPs and 41 mtDNA-CN associated phenotypes to identify functional domains, revealing three distinct groups, including platelet activation, megakaryocyte proliferation, and mtDNA metabolism. Finally, using mitochondrial SNPs, we establish causal relationships between mitochondrial function and a variety of blood cell-related traits, kidney function, liver function and overall (p = 0.044) and non-cancer mortality (p = 6.56 × 10-4).

White paper on peanut allergy - part 1: Epidemiology, burden of disease, health economic aspects

Peanuts are Leguminosae, commonly known as the legume or pea family, and peanut allergy is among the most common food allergies and the most common cause of fatal food reactions and anaphylaxis.

The prevalence of peanut allergy increased 3.5-fold over the past two decades reaching 1.4–2% in Europe and the United States. The reasons for this increase in prevalence are likely multifaceted. Sensitization via the skin appears to be associated with the development of peanut allergy and atopic eczema in infancy is associated with a high risk of developing peanut allergy.

Until recently, the only possible management strategy for peanut allergy was strict allergen avoidance and emergency treatment including adrenaline auto-injector in cases of accidental exposure and reaction.

This paper discusses the various factors that impact the risks of peanut allergy and the burden of self-management on peanut-allergic children and their caregivers.

Update of the S2k guideline on the management of IgE-mediated food allergies

Not available.

Tolerance development in cow's milk-allergic infants receiving amino acid-based formula: A randomized controlled trial

BACKGROUND

Tolerance development is an important clinical outcome for infants with cow's milk allergy.

OBJECTIVE

This multicenter, prospective, randomized, double-blind, controlled clinical study (NTR3725) evaluated tolerance development to cow's milk (CM) and safety of an amino acid-based formula (AAF) including synbiotics (AAF-S) comprising prebiotic oligosaccharides (oligofructose, inulin) and probiotic Bifidobacterium breve M-16V in infants with confirmed IgE-mediated CM allergy.

METHODS

Subjects aged ≤13 months with IgE-mediated CM allergy were randomized to receive AAF-S (n = 80) or AAF (n = 89) for 12 months. Stratification was based on CM skin prick test wheal size and study site. After 12 and 24 months, CM tolerance was evaluated by double-blind, placebo-controlled food challenge. A logistic regression model used the all-subjects randomized data set.

RESULTS

At baseline, mean ± SD age was 9.36 ± 2.53 months. At 12 and 24 months, respectively, 49% and 62% of subjects were CM tolerant (AAF-S 45% and 64%; AAF 52% and 59%), and not differ significantly between groups. During the 12-month intervention, the number of subjects reporting at least 1 adverse event did not significantly differ between groups; however, fewer subjects required hospitalization due to serious adverse events categorized as infections in the AAF-S versus AAF group (9% vs 20%; P = .036).

CONCLUSIONS

After 12 and 24 months, CM tolerance was not different between groups and was in line with natural outgrowth. Results suggest that during the intervention, fewer subjects receiving AAF-S required hospitalization due to infections.

Peanut-induced anaphylaxis in children and adolescents: Data from the European Anaphylaxis Registry

BACKGROUND

Peanut allergy has a rising prevalence in high-income countries, affecting 0.5%-1.4% of children. This study aimed to better understand peanut anaphylaxis in comparison to anaphylaxis to other food triggers in European children and adolescents.

METHODS

Data was sourced from the European Anaphylaxis Registry via an online questionnaire, after in-depth review of food-induced anaphylaxis cases in a tertiary paediatric allergy centre.

RESULTS

3514 cases of food anaphylaxis were reported between July 2007 - March 2018, 56% in patients younger than 18 years. Peanut anaphylaxis was recorded in 459 children and adolescents (85% of all peanut anaphylaxis cases). Previous reactions (42% vs. 38%; p = .001), asthma comorbidity (47% vs. 35%; p < .001), relevant cofactors (29% vs. 22%; p = .004) and biphasic reactions (10% vs. 4%; p = .001) were more commonly reported in peanut anaphylaxis. Most cases were labelled as severe anaphylaxis (Ring&Messmer grade III 65% vs. 56% and grade IV 1.1% vs. 0.9%; p = .001). Self-administration of intramuscular adrenaline was low (17% vs. 15%), professional adrenaline administration was higher in non-peanut food anaphylaxis (34% vs. 26%; p = .003). Hospitalization was higher for peanut anaphylaxis (67% vs. 54%; p = .004).

CONCLUSIONS

The European Anaphylaxis Registry data confirmed peanut as one of the major causes of severe, potentially life-threatening allergic reactions in European children, with some characteristic features e.g., presence of asthma comorbidity and increased rate of biphasic reactions. Usage of intramuscular adrenaline as first-line treatment is low and needs to be improved. The Registry, designed as the largest database on anaphylaxis, allows continuous assessment of this condition.

The Role of MicroRNA Expression for Proliferation and Apoptosis of Tumor Cells: Impact of Hypoxia-Related Acidosis

The metabolic microenvironment in tumors is characterized by hypoxia and acidosis. Extracellular pH sometimes decreases to even below 6.0. Previous experiments showed that tissue pH has an impact on tumor cell proliferation and apoptosis. However, the mechanism of how cell cycle progression is affected by decreased pH is not fully understood yet. One possible mechanism includes changes in the expression of miRNAs. The aim of this study was to analyze the impact of pH-regulated miRNAs (miR-183 and miR-215) on proliferation, apoptosis, and necrosis of tumor cells. Therefore, AT1 prostate and Walker-256 mammary carcinoma cells were transfected with the miRNAs or with the respective antagomirs and incubated at pH 7.4 and 6.6 for 24 h. AT1 cells underwent a G0/G1 cell cycle arrest under acidic conditions and showed a marked reduction of the number of actively DNA-synthesizing cells. In Walker-256 cells, acidosis induced a reduction of apoptosis and additionally a significant increase in necrotic cell death. Transfection of tumor cells with miR-183 or miR-215, which were significantly downregulated under acidic conditions, had no impact on cell death of AT1 or Walker-256 cells. Overexpression of miR-183, which is also downregulated by acidosis, intensified G0/G1 cell cycle arrest in AT1 cells. Previous studies revealed that hypoxia-related tumor acidosis affects the expression of different small noncoding RNAs. However, not all of these acidosis-regulated miRNAs seem to have an impact on proliferation, apoptosis, and necrosis of tumor cells. While miR-215 had no influence, miR-183 seems to be an interesting candidate that could amplify the impact of extracellular acidosis on malignant behavior of tumor cells.

Functional Impact of Acidosis-Regulated MicroRNAs on the Migration and Adhesion of Tumor Cells

Tumor tissue shows special features in metabolism in contrast to healthy tissue. Besides a distinctive oxygen deficiency, tumors often show a reduced extracellular pH (acidosis) resulting from an intensified glycolysis not only under hypoxic but also under normoxic conditions (Warburg effect). As shown in previous studies, cell migration is increased in AT1 prostate carcinoma cells after incubation at pH 6.6, and this leads to an increased number of lung metastases in vivo. However, the signaling pathway causing these functional changes is still unknown. Possible mediators could be acidosis-regulated microRNAs (miR-7, miR-183, miR-203, miR-215). The aim of the study was therefore to analyze whether a change in the expression of these microRNAs has an impact on the tumor cell migration and adhesion. Studies were performed with AT1 rat prostate cancer cells which were incubated for 24 h at pH 7.4 or 6.6. Keeping AT1 tumor cells at low pH increased the migratory capacity by about 100%. But also the decrease of miR-203 and miR-215 expression (at normal pH) led to an increase in migration velocity by 50%. In contrast, cell adhesion was increased by about 75% at low pH. However, an increase in miR-215 expression at pH 6.6 reduced the adhesion by trend. These results clearly indicated that the extracellular pH has an impact on migration and adhesion of tumor cells. In this mechanism, pH-regulated microRNAs could play a role since changes in the expression of these microRNAs (especially miR-203) are also able to modulate the migratory behavior.

Risk Factors and Characteristics of Biphasic Anaphylaxis

BACKGROUND

Anaphylaxis is an immediate hypersensitivity reaction. However, a biphasic course with the second onset of symptoms can occur hours after the initial phase. Little is known about the causes of biphasic anaphylaxis making the identification of patients at risk difficult.

OBJECTIVE

To identify factors predisposing for biphasic anaphylaxis for the better understanding of these reactions.

METHODS

Data from the Anaphylaxis Registry (from 11 countries) including 8736 patients with monophasic and 435 biphasic anaphylaxis were analyzed.

RESULTS

The rate of biphasic reactions in this large cohort was 4.7%. The identified risk factors were reaction severity (grade III/IV vs grade II: odds ratio [OR] = 1.34; 95% confidence interval [CI]: 1.1-1.62); multiorgan involvement; skin, gastrointestinal, severe respiratory, and cardiac symptoms; anaphylaxis caused by peanut/tree nut (OR = 1.78; 95% CI: 1.38-2.23) or an unknown elicitor (OR = 1.96; 95% CI: 1.41-2.72); exercise as a cofactor (OR = 1.44; 95% CI: 1.17-1.78); chronic urticaria as a comorbidity (OR = 2.12; 95% CI: 1.19-3.78); a prolonged interval between the contact with the elicitor and start of primary symptoms (OR for >30 vs <30 min: 1.38; 95% CI: 1.08-1.76); and antihistamine treatment (OR = 1.52; 95% CI: 1.14-2.02).

CONCLUSION

A biphasic course of anaphylaxis occurs more frequently in severely affected patients with multiorgan involvement. However, we identified multiple additional predictors, suggesting that the pathogenesis of biphasic reactions is more complex than being a rebound of a severe primary reaction.

Long-term, open-label extension study of the efficacy and safety of epicutaneous immunotherapy for peanut allergy in children: PEOPLE 3-year results

BACKGROUND

The PEPITES (Peanut EPIT Efficacy and Safety) trial, a 12-month randomized controlled study of children with peanut allergy and 4 to 11 years old, previously reported the safety and efficacy of epicutaneous immunotherapy (EPIT) for peanut allergy (250 μg, daily epicutaneous peanut protein; DBV712 250 μg).

OBJECTIVE

We sought to assess interim safety and efficacy of an additional 2 years of EPIT from the ongoing (5-year treatment) PEOPLE (PEPITES Open-Label Extension) study.

METHODS

Subjects who completed PEPITES were offered enrollment in PEOPLE. Following an additional 2 years of daily DBV712 250 μg, subjects who had received DBV712 250 μg in PEPITES underwent month-36 double-blind, placebo-controlled food challenge with an optional month-38 sustained unresponsiveness assessment.

RESULTS

Of 213 eligible subjects who had received DBV712 250 μg in PEPITES, 198 (93%) entered PEOPLE, of whom 141 (71%) had assessable double-blind, placebo-controlled food challenge at month 36. At month 36, 51.8% of subjects (73 of 141) reached an eliciting dose of ≥1000 mg, compared with 40.4% (57 of 141) at month 12; 75.9% (107 of 141) demonstrated increased eliciting dose compared with baseline; and 13.5% (19 of 141) tolerated the full double-blind, placebo-controlled food challenge of 5444 mg. Median cumulative reactive dose increased from 144 to 944 mg. Eighteen subjects underwent an optional sustained unresponsiveness assessment; 14 of those (77.8%) maintained an eliciting dose of ≥1000 mg at month 38. Local patch-site skin reactions were common but decreased over time. There was no treatment-related epinephrine use in years 2 or 3. Compliance was high (96.9%), and withdrawals due to treatment-related adverse events were low (1%).

CONCLUSIONS

These results demonstrate that daily EPIT treatment for peanut allergy beyond 1 year leads to continued response from a well-tolerated, simple-to-use regimen.

Secondary prevention measures in anaphylaxis patients: Data from the anaphylaxis registry

BACKGROUND

Patients with a history of anaphylaxis are at risk of future anaphylactic reactions. Thus, secondary prevention measures are recommended for these patients to prevent or attenuate the next reaction.

METHODS

Data from the Anaphylaxis Registry were analyzed to identify secondary prevention measures offered to patients who experienced anaphylaxis. Our analysis included 7788 cases from 10 European countries and Brazil.

RESULTS

The secondary prevention measures offered varied across the elicitors. A remarkable discrepancy was observed between prevention measures offered in specialized allergy centers (84% of patients were prescribed adrenaline autoinjectors following EAACI guidelines) and outside the centers: Here, EAACI guideline adherence was only 37%. In the multivariate analysis, the elicitor of the reaction, age of the patient, mastocytosis as comorbidity, severity of the reaction, and reimbursement/availability of the autoinjector influence physician's decision to prescribe one.

CONCLUSIONS

Based on the low implementation of guidelines concerning secondary prevention measures outside of specialized allergy centers, our findings highlight the importance of these specialized centers and the requirement of better education for primary healthcare and emergency physicians.

Capsid Engineering Overcomes Barriers Toward Adeno-Associated Virus Vector-Mediated Transduction of Endothelial Cells

Endothelial cells (EC) are targets in gene therapy and regenerative medicine, but they are inefficiently transduced with adeno-associated virus (AAV) vectors of various serotypes. To identify barriers hampering efficient transduction and to develop an optimized AAV variant for EC transduction, we screened an AAV serotype 2-based peptide display library on primary human macrovascular EC. Using a new high-throughput selection and monitoring protocol, we identified a capsid variant, AAV-V_EC, which outperformed the parental serotype as well as first-generation targeting vectors in EC transduction. AAV vector uptake was improved, resulting in significantly higher transgene expression levels from single-stranded vector genomes detectable within a few hours post-transduction. Notably, AAV-V_EC transduced not only proliferating EC but also quiescent EC, although higher particle-per-cell ratios had to be applied. Also, induced pluripotent stem cell-derived endothelial progenitor cells, a novel tool in regenerative medicine and gene therapy, were highly susceptible toward AAV-V_EC transduction. Thus, overcoming barriers by capsid engineering significantly expands the AAV tool kit for a wide range of applications targeting EC.

Der Stand der allergologischen Weiterbildung von Kinderärzten

Hintergrund

Ein deutlicher Rückgang abgelegter Prüfungen im Fach Allergologie und gleichzeitig eine Zunahme allergologischer Erkrankungen haben die Nachwuchsgruppe der Gesellschaft für Pädiatrische Allergologie und Umweltmedizin (GPAU) dazu bewogen, die Qualität und die Bedingungen der allergologischen Ausbildung in der Pädiatrie zu untersuchen. Zeitgleich wurde beim Deutschen Ärztetag ein neues Format der Zusatzweiterbildung Allergologie (Musterweiterbildungsordnung [MWBO]) verabschiedet.

Ziel der Arbeit

Ziel dieser Umfrage war es, die Rahmenbedingungen der allergologischen Ausbildung von Kinderärzten in Deutschland genauer zu untersuchen.

Material und Methoden

Es wurde eine Umfrage mithilfe eines Fragebogens sowohl bei den Weiterbildungsermächtigten (insgesamt 169) als auch bei deren Weiterbildungsassistent*innen durchgeführt.

Ergebnisse und Diskussion

Von insgesamt 56 Weiterbildungsermächtigten und 32 Weiterbildungsassistent*innen  wurde  der  Fragebogen ausgewertet. Es zeigt sich in der Auswertung, dass der Prozentsatz an Frauen bei den Weiterbildungsermächtigten deutlich geringer ist im Vergleich zu den Weiterbildungsassistent*innen (20 vs. 66 %), jedoch sind mittlerweile mehr als zwei Drittel der Medizinstudierenden weiblich. In der Umfrage stellt sich heraus, dass die allergologische Weiterbildung bei fast 20 % der Weiterbildungsassistent*innen weniger als 10 % der Gesamtarbeitszeit ausmacht und oft außerhalb der Regelarbeitszeit stattfindet. Es sind in Zukunft sowohl flexiblere Arbeitszeitmodelle als auch kombinierte Ausbildungsmodelle zwischen Klinik und Praxis und feste Strukturen für eine fundierte Ausbildung im klinischen Alltag notwendig, um der wachsenden Anzahl allergologischer Fragestellungen v. a. bei Kindern flächendeckend gerecht werden zu können. In der neuen MWBO darf nicht nur der Nachweis von Untersuchungstechniken eine Rolle spielen, sondern sie muss auch die Betreuung von komplexen allergologischen Fällen abbilden, die gerade in der Pädiatrie vorzufinden sind, z. B. im Rahmen von Hospitationen.

Genome-wide meta-analysis of variant-by-diuretic interactions as modulators of lipid traits in persons of European and African ancestry

Hypertension (HTN) is a significant risk factor for cardiovascular morbidity and mortality. Metabolic abnormalities, including adverse cholesterol and triglycerides (TG) profiles, are frequent comorbid findings with HTN and contribute to cardiovascular disease. Diuretics, which are used to treat HTN and heart failure, have been associated with worsening of fasting lipid concentrations. Genome-wide meta-analyses with 39,710 European-ancestry (EA) individuals and 9,925 African-ancestry (AA) individuals were performed to identify genetic variants that modify the effect of loop or thiazide diuretic use on blood lipid concentrations. Both longitudinal and cross-sectional data were used to compute cohort-specific interaction results, which were then combined through meta-analysis in each ancestry. These ancestry-specific results were further combined through trans-ancestry meta-analysis. Analysis of EA data identified two genome-wide significant (p < 5×10⁻⁸) loci with single nucleotide variant (SNV)-loop diuretic interaction on TG concentrations (including COL11A1). Analysis of AA data identified one genome-wide significant locus adjacent to BMP2 with SNV-loop diuretic interaction on TG concentrations. Trans-ancestry analysis strengthened evidence of association for SNV-loop diuretic interaction at two loci (KIAA1217 and BAALC). There were few significant SNV-thiazide diuretic interaction associations on TG concentrations and for either diuretic on cholesterol concentrations. Several promising loci were identified that may implicate biologic pathways that contribute to adverse metabolic side effects from diuretic therapy.

Loss of resources and demoralization in the chronically ill

OBJECTIVE

The study examined whether the association between the severity of physical symptoms and demoralization is mediated by loss of resources in individuals with chronic conditions including conventional diagnoses, functional somatic syndromes, and medically unexplained symptoms.

METHOD

This cross-sectional study evaluated N = 194 patients (mean age = 46, 83.5% female) who reported at least 3 months of persistent physical symptoms using the following self-report instruments: PHQ-15 (modified), Loss of Resources Inventory, Psychosocial Questionnaire - Demoralization Subscale, and PHQ-8. The mediation hypothesis was tested by multiple regression analyses controlling for age, race, employment status, income, educational attainment, and depression.

RESULTS

Participants experienced M = 9.3 out of 16 possible health-related losses (SD = 4.4). Average to severe demoralization scores were indicated by 59.1% of individuals, of which only 17.1% experienced high demoralization. Loss of resources fully mediated the effect of symptom severity on demoralization, explaining 56% of the variance of demoralization and inhibiting the initially significant effect of symptom severity on demoralization to nonsignificant levels [from b = 0.67, 95% CI (0.26, 1.07) to b = 0.03, 95% CI (-0.27, 0.32)].

CONCLUSION

Early recognition of the loss of resources phenomena and interventions to reduce its progression through the introduction of resource gains may diminish, or even prevent, the installation of demoralization in individuals with chronic symptoms.

Effect of Epicutaneous Immunotherapy vs Placebo on Reaction to Peanut Protein Ingestion Among Children With Peanut Allergy: The PEPITES Randomized Clinical Trial

IMPORTANCE

There are currently no approved treatments for peanut allergy.

OBJECTIVE

To assess the efficacy and adverse events of epicutaneous immunotherapy with a peanut patch among peanut-allergic children.

DESIGN, SETTING, AND PARTICIPANTS

Phase 3, randomized, double-blind, placebo-controlled trial conducted at 31 sites in 5 countries between January 8, 2016, and August 18, 2017. Participants included peanut-allergic children (aged 4-11 years [n = 356] without a history of a severe anaphylactic reaction) developing objective symptoms during a double-blind, placebo-controlled food challenge at an eliciting dose of 300 mg or less of peanut protein.

INTERVENTIONS

Daily treatment with peanut patch containing either 250 μg of peanut protein (n = 238) or placebo (n = 118) for 12 months.

MAIN OUTCOMES AND MEASURES

The primary outcome was the percentage difference in responders between the peanut patch and placebo patch based on eliciting dose (highest dose at which objective signs/symptoms of an immediate hypersensitivity reaction developed) determined by food challenges at baseline and month 12. Participants with baseline eliciting dose of 10 mg or less were responders if the posttreatment eliciting dose was 300 mg or more; participants with baseline eliciting dose greater than 10 to 300 mg were responders if the posttreatment eliciting dose was 1000 mg or more. A threshold of 15% or more on the lower bound of a 95% CI around responder rate difference was prespecified to determine a positive trial result. Adverse event evaluation included collection of treatment-emergent adverse events (TEAEs).

RESULTS

Among 356 participants randomized (median age, 7 years; 61.2% male), 89.9% completed the trial; the mean treatment adherence was 98.5%. The responder rate was 35.3% with peanut-patch treatment vs 13.6% with placebo (difference, 21.7% [95% CI, 12.4%-29.8%; P < .001]). The prespecified lower bound of the CI threshold was not met. TEAEs, primarily patch application site reactions, occurred in 95.4% and 89% of active and placebo groups, respectively. The all-causes rate of discontinuation was 10.5% in the peanut-patch group vs 9.3% in the placebo group.

CONCLUSIONS AND RELEVANCE

Among peanut-allergic children aged 4 to 11 years, the percentage difference in responders at 12 months with the 250-μg peanut-patch therapy vs placebo was 21.7% and was statistically significant, but did not meet the prespecified lower bound of the confidence interval criterion for a positive trial result. The clinical relevance of not meeting this lower bound of the confidence interval with respect to the treatment of peanut-allergic children with epicutaneous immunotherapy remains to be determined.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02636699.

Allergen Recognition Patterns in Walnut Allergy Are Age Dependent and Correlate with the Severity of Allergic Reactions

BACKGROUND

Walnut is an important elicitor of food allergy in children and adults with a high rate of severe reactions. Multicenter studies using a common clinical protocol and a comprehensive allergen are lacking.

OBJECTIVE

To investigate potential correlations between molecular sensitization patterns and clinical characteristics of walnut-allergic patients.

METHODS

A total of 91 walnut-allergic subjects and 24 tolerant controls from Switzerland, Germany, and Spain were included. Walnut allergy was established by food challenge in all but anaphylactic subjects. Specific IgE (sIgE) to walnut extract, rJug r 1 (2S albumin), rJug r 3 (nonspecific lipid transfer protein 1), nJug r 4 (11S globulin), rJug r 5 (PR-10 protein), 2 vicilin fractions, profiling, and cross-reactive carbohydrate determinant was determined by ImmunoCAP. A threshold of 0.10 kU_A/L was used for positivity.

RESULTS

Sensitivity of sIgE to walnut extract was 87% and increased to 96% for the sum of all walnut components. sIgE to walnut extract and all walnut components, except rJug r 5, was significantly higher in patients younger than 14 years at inclusion. Stratification by age at onset of walnut allergy led to similar results. All patients younger than 14 years had severe reactions, whereas 38% of patients 14 years or older were mild reactors. Severe reactors (n = 70) had higher sIgE levels than did mild reactors (n = 21) to walnut extract (P < .0001), rJug r 1 (P < .0001), nJug r 4 (P = .0003), and both vicilin fractions (P < .0001), but not to Jug r 3 and Jug r 5.

CONCLUSIONS

Sensitization to walnut storage proteins is acquired in childhood and correlates with severe reactions. sIgE levels to storage proteins Jug r 1 and Jug r 4 and vicilin fractions, but not to nonspecific lipid transfer protein and PR-10 proteins, correlate with systemic reactions to walnut.

Factors increasing the risk for a severe reaction in anaphylaxis: An analysis of data from The European Anaphylaxis Registry

BACKGROUND

Preventive measures to decrease the frequency and intensity of anaphylactic events are essential to provide optimal care for allergic patients. Aggravating factors may trigger or increase the severity of anaphylaxis and therefore need to be recognized and avoided.

OBJECTIVE

To identify and prioritize factors associated with an increased risk of developing severe anaphylaxis.

METHODS

Data from the Anaphylaxis Registry (122 centers in 11 European countries) were used in logistic regression models considering existing severity grading systems, elicitors, and symptoms to identify the relative risk of factors on the severity of anaphylaxis.

RESULTS

We identified higher age and concomitant mastocytosis (OR: 3.1, CI: 2.6-3.7) as the most important predictors for an increased risk of severe anaphylaxis. Vigorous physical exercise (OR: 1.5, CI: 1.3-1.7), male sex (OR: 1.2, CI: 1.1-1.3), and psychological burden (OR: 1.4, CI: 1.2-1.6) were more often associated with severe reactions. Additionally, intake of beta-blockers (OR: 1.9, CI: 1.5-2.2) and ACE-I (OR: 1.28, CI: 1.05, 1.51) in temporal proximity to allergen exposition was identified as an important factor in logistic regression analysis.

CONCLUSION

Our data suggest it may be possible to identify patients who require intensified preventive measures due to their relatively higher risk for severe anaphylaxis by considering endogenous and exogenous factors.

Epinephrine in Severe Allergic Reactions: The European Anaphylaxis Register

BACKGROUND

Current guidelines recommend intramuscular administration of epinephrine as the first-line drug for the emergency treatment of severe allergic reactions (anaphylaxis), but no randomized trial evidence supports this consensus.

OBJECTIVE

We aimed to assess anaphylaxis treatment practices over 10 years, covering several European regions, all allergen sources, and all age groups.

METHODS

The European Anaphylaxis Register tracks elicitors, symptoms, emergency treatment, diagnostic workups, and long-term counseling for anaphylaxis incidents through web-based data entry from tertiary allergy specialists, covering information from the emergency respondent, patient, tertiary referral, and laboratory/clinical test results.

RESULTS

We analyzed 10,184 anaphylaxis incidents. In total, 27.1% of patients treated by a health professional received epinephrine and, in total, 10.5% received a second dose. Successful administration was less frequent in German-speaking countries (minimum 19.6%) than in Greece, France, and Spain (maximum 66.7%). Over the last decade, epinephrine administration from a health professional almost doubled to reach 30.6% in 2015-2017, half of which was applied intramuscularly. A total of 14.7% of lay- or self-treated cases were treated with an autoinjector. Of those without treatment, 22.4% carried a device for administration. No change in successful administration by lay emergency respondents was found over the last 10 years. Of the reaction and patient characteristics analyzed, only clinical severity considerably influenced the likelihood of receiving epinephrine, with 66.9% of successful administrations in near-fatal (grade IV) reactions.

CONCLUSIONS

Despite clear recommendations, only a small proportion of anaphylaxis incidents are treated with epinephrine. We demonstrated a slight increase in treated patients when handled by professionals, but stagnation in lay- or self-treated anaphylaxis. The reaction circumstances, the respondent's professional background, and patient characteristics did not explain which reactions were treated.

Ana o 3-specific IgE is a good predictor for clinically relevant cashew allergy in children

INTRODUCTION

Component-resolved diagnostics using specific IgE to 2 S albumins has shown to be a valuable new option in diagnostic procedure. Ana o 3 is a 2 S albumin from cashew. The aim of this study was to investigate the role of Ana o 3-specific serum IgE in the diagnosis of cashew allergy and to identify cut-off levels to replace oral food challenges. Moreover, the value of additional determination of total IgE has been investigated.

METHODS

In a multicentre study, we analysed specific IgE to cashew extract and Ana o 3 as well as total IgE in children with suspected cashew allergy using the ImmunoCAP-FEIA and a standardized diagnostic procedure including oral challenges where indicated.

RESULTS

A total of 61 patients were included in the study. Forty-two were allergic to cashew, and 19 were tolerant. In receiver operating curves, Ana o 3 discriminates between allergic and tolerant children better than cashew-specific IgE with an area under the curve of 0.94 vs 0.78. The ratio of Ana o 3-specific IgE to total IgE did not further improve the diagnostic procedure. Probability curves for Ana o 3-specific IgE have been calculated, and a 95% probability could be estimated at 2.0 kU/l.

CONCLUSION

Specific IgE to Ana o 3 is a valuable tool for the diagnosis of cashew allergy. Considering its positive predictive value, it might allow to make a considerable number of oral challenges superfluous.

A novel tool for stable nitrogen isotope analysis in aqueous samples

RATIONALE

Bulk stable isotope analysis (BSIA) of dissolved matter (e.g. dissolved organic carbon, total nitrogen bound (TN_b ), etc.) is of particular importance since this pool is a prime conduit in the cycling of N and C. Studying the two elemental pools is of importance, as transformation and transport processes of N and C are inextricably linked in all biologically mediated systems. No system able to analyze natural abundance stable carbon and nitrogen isotope composition in aqueous samples (without offline sample preparation) and simultaneously has been reported so far. Extension of the high-temperature combustion (HTC) system, to be capable of measuring TN_b stable nitrogen isotope composition, is described in this study.

METHODS

To extend the TOC analyzer to be capable of measuring TN_b , modifications from the HTC high-performance liquid chromatography/isotope ratio mass spectrometry (HPLC/IRMS) interface were implemented and expanded. A reduction reactor for conversion of NO_x into N₂ was implemented into the new developed system. The extension addresses mainly the development of the focusing unit for nitrogen and a degassing device for online separation of TN_b from molecular nitrogen (N₂ ) prior to injection.

RESULTS

The proof of principle of the system was demonstrated with different compound solutions. In this initial testing, the δ¹⁵ N_AIR-N2 values of the tested compounds were determined with precision and trueness of typically ≤0.5‰. Good results (u ≤ 0.5‰) could be achieved down to a TN_b concentration of 40 mgN/L and acceptable results (u ≤ 1.0‰) down to 5 mgN/L. In addition, the development resulted in the first system reported to be suitable for simultaneous and direct δ¹³ C and δ¹⁵ N BSIA of aqueous samples.

CONCLUSIONS

The development resulted in the first system shown to be suitable for both δ¹³ C and δ¹⁵ N direct BSIA in aqueous samples. This system could open up new possibilities in SIA-based research fields. Copyright © 2016 John Wiley & Sons, Ltd.