The component-specific to total IgE ratios do not improve peanut and hazelnut allergy diagnoses

Longitudinal peanut and Ara h 2 specific-IgE, -IgG4, and -IgG4/-IgE ratios are associated with the natural resolution of peanut allergy in childhood

BACKGROUND

There are no studies of longitudinal immunoglobulin measurements in a population-based cohort alongside challenge-confirmed peanut allergy outcomes. Little is known about biomarkers for identifying naturally resolving peanut allergy during childhood.

OBJECTIVES

To measure longitudinal trends in whole peanut and component Ara h 2 sIgE and sIgG4 in the first 10 years of life, in a population cohort of children with challenge-confirmed peanut allergy, and to determine whether peanut-specific immunoglobulin levels or trends are associated with peanut allergy persistence or resolution by 10 years of age.

METHODS

One-year-old infants with challenge-confirmed peanut allergy (n = 156) from the HealthNuts study (n = 5276) were prospectively followed at ages 4, 6, and 10 years with questionnaires, skin prick tests, oral food challenges, and plasma total-IgE, sIgE and sIgG4 to peanut and Ara h 2.

RESULTS

Peanut allergy resolved in 33.9% (95% CI = 25.3%, 43.3%) of children by 10 years old with most resolving (97.4%, 95% CI = 86.5%, 99.9%) by 6 years old. Decreasing Ara h 2 sIgE (p = .01) and increasing peanut sIgG4 (p < .001), Ara h 2 sIgG4 (p = .01), peanut sIgG4/sIgE (p < .001) and Ara h 2 sIgG4/sIgE (p < .001) from 1 to 10 years of age were associated with peanut allergy resolution. Peanut sIgE measured at 1 year old had the greatest prognostic value (AUC = 0.75 [95% CI = 0.66, 0.82]); however, no single threshold produced both high sensitivity and specificity.

CONCLUSION

One third of infant peanut allergy resolved by 10 years of age. Decreasing sIgE and sIgG4 to peanut and Ara h 2 over time were associated with natural resolution of peanut allergy. However, biomarker levels at diagnosis were not strongly associated with the natural history of peanut allergy.

Systematic review and meta-analyses on the accuracy of diagnostic tests for IgE-mediated food allergy

The European Academy of Allergy and Clinical Immunology (EAACI) is updating the Guidelines on Food Allergy Diagnosis. We aimed to undertake a systematic review of the literature with meta-analyses to assess the accuracy of diagnostic tests for IgE-mediated food allergy. We searched three databases (Cochrane CENTRAL (Trials), MEDLINE (OVID) and Embase (OVID)) for diagnostic test accuracy studies published between 1 October 2012 and 30 June 2021 according to a previously published protocol (CRD42021259186). We independently screened abstracts, extracted data from full texts and assessed risk of bias with QUADRAS 2 tool in duplicate. Meta-analyses were undertaken for food-test combinations for which three or more studies were available. A total of 149 studies comprising 24,489 patients met the inclusion criteria and they were generally heterogeneous. 60.4% of studies were in children ≤12 years of age, 54.3% were undertaken in Europe, ≥95% were conducted in a specialized paediatric or allergy clinical setting and all included oral food challenge in at least a percentage of enrolled patients, in 21.5% double-blind placebo-controlled food challenges. Skin prick test (SPT) with fresh cow's milk and raw egg had high sensitivity (90% and 94%) for milk and cooked egg allergies. Specific IgE (sIgE) to individual components had high specificity: Ara h 2-sIgE had 92%, Cor a 14-sIgE 95%, Ana o 3-sIgE 94%, casein-sIgE 93%, ovomucoid-sIgE 92/91% for the diagnosis of peanut, hazelnut, cashew, cow's milk and raw/cooked egg allergies, respectively. The basophil activation test (BAT) was highly specific for the diagnosis of peanut (90%) and sesame (93%) allergies. In conclusion, SPT and specific IgE to extracts had high sensitivity whereas specific IgE to components and BAT had high specificity to support the diagnosis of individual food allergies.

Revealing clinically relevant specific IgE sensitization patterns in Hymenoptera venom allergy with dimension reduction and clustering

Background

Immunoglobulin E (IgE) blood tests are used to detect sensitizations and potential allergies. Recent studies suggest that specific IgE sensitization patterns due to molecular interactions affect an individual's risk of developing allergic symptoms.

Objective

The aim of this study was to reveal specific IgE sensitization patterns and investigate their clinical implications in Hymenoptera venom allergy.

Methods

In this cross-sectional study, 257 hunters or fishers with self-filled surveys on previous Hymenoptera stings were analyzed. Blood samples were taken to determine Hymenoptera IgE sensitization levels. Using dimensionality reduction and clustering, specific IgE for 10 Hymenoptera venom allergens were evaluated for clinical relevance.

Results

Three clusters were unmasked using novel dimensionality reduction and clustering methods solely based on specific IgE levels to Hymenoptera venom allergens. These clusters show different characteristics regarding previous systemic reactions to Hymenoptera stings.

Conclusion

Our study was able to unmask non-linear sensitization patterns for specific IgE tests in Hymenoptera venom allergy. We were able to derive risk clusters for anaphylactic reactions following hymenoptera stings and pinpoint relevant allergens (rApi m 10, rVes v 1, whole bee, and wasp venom) for clustering.

Natural History of Hazelnut Allergy and Current Approach to Its Diagnosis and Treatment

Hazelnut allergy is the most prevalent type of nut allergy in Europe, with symptoms that can range from mild, such as hives and itching, to severe, such as anaphylaxis, particularly in patients who are sensitized to highly stable allergens, such as storage proteins. Compared to other types of food allergies, allergies to tree nuts, including hazelnuts, tend to persist throughout life. Although symptoms can appear in early childhood, they often continue into adulthood, with a minority of cases improving during adolescence. Currently, there is no curative treatment available for hazelnut allergy, and patients must adhere to a restrictive diet and carry autoinjective epinephrine. However, oral allergen immunotherapy (AIT) is a promising treatment option. Patients can be categorized based on their risk for severe reactions using various clinical, in vivo, and in vitro tests, including component-resolved diagnosis and oral food challenge. This review aims to provide an overview of the current knowledge of the natural history of hazelnut allergy and new approaches for its diagnosis and management.

IgE-Mediated food allergy: Current diagnostic modalities and novel biomarkers with robust potential

Food allergy (FA) is a serious public health issue afflicting millions of people globally, with an estimated prevalence ranging from 1-10%. Management of FA is challenging due to overly restrictive diets and the lack of diagnostic approaches with high accuracy and prediction. Although measurement of serum-specific antibodies combined with patient medical history and skin prick test is a useful diagnostic tool, it is still an imprecise predictor of clinical reactivity with a high false-positive rate. The double-blind placebo-controlled food challenge represents the gold standard for FA diagnosis; however, it requires large healthcare and involves the risk of acute onset of allergic reactions. Improvement in our understanding of the molecular mechanism underlying allergic disease pathology, development of omics-based methods, and advances in bioinformatics have boosted the generation of a number of robust diagnostic biomarkers of FA. In this review, we discuss how traditional diagnostic modalities guide appropriate diagnosis and management of FA in clinical practice, as well as uncover the potential of the latest biomarkers for the diagnosis, monitoring, and prediction of FA. We also raise perspectives for precise and targeted medical intervention to fill the gap in the diagnosis of FA.

Real world use of peanut component testing among children in the Chicago metropolitan area

Background: Peanut component tests (PCT) have become important in the evaluation of peanut allergy. There remains a paucity of research across the United States in investigating the utility of PCT in clinical practice in conjunction with current standards of care. Objective: The primary aims were to evaluate the performance and sensitization patterns of PCT in clinical practice when first available at our institution. Methods: We performed a retrospective chart review of 184 children with PCT and oral food challenge (OFC) results between 2012 and 2017. Simple logistic regression models assessed the associations between PCT and OFC outcomes. Receiver operator characteristic curves were constructed, and a predicted probability curve was derived for Ara h2. Results: The median (interquartile range [IQR]) age at OFC was 4 years (2-7 years), and 111 patients (60%) were boys. Ara h 2 was the most commonly sensitized PCT. Sixty-one patients (33%) reacted at OFC. Ara h 2 specific immunoglobulin E (sIgE) ≥ 0.35 kU_A/L was associated with increased odds of reacting at OFC (odds ratio 5.91 95% confidence interval, 2.93-11.89; p < 0.001); however, 19 patients (37%) positive for Ara h 2 did not react. Ara h 2 sIgE of 0.49 kU_A/L and 4.58 kU_A/L were associated with 50% and 90% probability, respectively, of reacting at OFC. Among those sensitized only to Ara h 8 or 9 (n = 21), 86% had no reaction. There was no statistically significant association with polysensitization to Ara h 1, 2, and 3, and peanut OFC outcome. Conclusion: Although the Ara h 2 sIgE value was associated with clinical reactivity, a significant proportion of the patients sensitized to Ara h 2 tolerated peanut. OFC remains an important tool in the evaluation of peanut allergy.

Integration of in vitro allergy test results and ratio analysis for the diagnosis and treatment of allergic patients (INTEGRA)

The introduction of molecular diagnosis into routine clinical practice has substantially improved the diagnosis and management of allergic patients by allowing clinicians to precisely identify the allergenic molecule responsible for immunoglobulin E (IgE)‐mediated allergies. However, it can be challenging to accurately interpret the results of molecular assays, partly due to the limited evidence base. In this context, a panel of experts with extensive experience in interpreting in vitro measures of total and serum specific IgE reviewed the available scientific evidence. After this review, the panel selected a series of representative case studies to demonstrate how determination of specific and total IgE values and the relationship between them (ratio analysis) can add value to the diagnostic process by more precisely defining the patient’s sensitization profile. Finally, the experts developed a series of recommendations on the clinical application of ratio analysis to optimize and complement the classical approach to allergy diagnosis.

Association Between Patients' Immunoglobulin E Levels and Difficulty Eradicating Helicobacter pylori

Background

Helicobacter pylori is a cause of gastric cancer, and thus the eradication of this bacterium is very important. The success rate of primary eradication has been dramatically increased by the introduction of potassium-competitive acid blockers. However, H. pylori cannot be eradicated in all patients, and the contributing factors need to be clarified.

Aim

Because allergy status may be a factor and considering research linking hay fever with eradication failure, the purpose of this study was to examine blood immunoglobulin E levels as a contributing factor in patients who were unable to eradicate H. pylori in a single eradication treatment and who underwent multiple eradication attempts.

Methods

Questionnaire data were collected from 250 patients who visited the Department of Gastroenterology, Hamamatsu University School of Medicine, for H. pylori eradication. In addition, non-specific IgE levels in the blood were measured and analyzed with one-way analysis of variance. Multinomial logistic regression analysis was performed to examine the association between the number of eradication attempts and the IgE level (< 500 vs ≥ 500 IU/mL).

Results

The mean IgE values were 188.4, 211.9, and 744.0 IU/mL in patients with one, two, and three or more eradication attempts, respectively (P < 0.05). The results of multinomial logistic regression analysis showed that attempting eradication three or more times was significantly associated with high levels of IgE, even after consideration of antibiotic sensitivity.

Conclusion

H. pylori eradication was less likely in patients with high IgE. It is thus necessary to study the appropriate regimen for patients with high IgE levels.

Peanut diversity and specific activity are the dominant IgE characteristics for effector cell activation in children

Background

IgE mediates allergic reactions to peanut; however, peanut-specific IgE (sIgE) levels do not always equate to clinical peanut allergy. Qualitative differences between sIgE of peanut-sensitized but tolerant (PS) and peanut-allergic (PA) individuals may be important.

Objective

We sought to assess the influence of IgE characteristics on effector cell activation in peanut allergy.

Methods

A cohort of 100 children was studied. The levels of IgE to peanut and peanut components were measured. Specific activity (SA) was estimated as the ratio of allergen-sIgE to total IgE. Avidity was measured by ImmunoCAP with sodium thiocyanate. IgE diversity was calculated on the basis of ImmunoCAP-Immuno Solid-phase Allergen Chip assays for 112 allergens or for 6 peanut allergens. Whole-blood basophils and mast cell line Laboratory of Allergic Diseases 2 sensitized with patients’ plasma were stimulated with peanut or controls and assessed by flow cytometry.

Results

SA to peanut (P < .001), Ara h 1 (P = .004), Ara h 2 (P < .001), Ara h 3 (P = .02), and Ara h 6 (P < .001) and the avidity of peanut-sIgE (P < .001) were higher in PA than in PS individuals. Diversity for peanut allergens was greater in PA individuals (P < .001). All IgE characteristics were correlated with basophil and mast cell activation. Peanut SA (R = 0.447) and peanut diversity (R = 0.440) had the highest standardized β-coefficients in combined multivariable regression models (0.447 and 0.440, respectively).

Conclusions

IgE specificity, SA, avidity, and peanut diversity were greater in PA than in PS individuals. IgE peanut SA and peanut diversity had the greatest influence on effector cell activation and could be used clinically.

Array-based measurements of aero-allergen-specific IgE correlate with skin-prick test reactivity in asthma regardless of specific IgG4 or total IgE measurements

Skin prick testing (SPT) and measurement of serum allergen-specific IgE (sIgE) are used to investigate asthma and other allergic conditions. Measurement of serum total IgE (tIgE) and allergen-specific IgG4 (sIgG4) may also be useful. The aim was to ascertain the correlation between these serological parameters and SPT. Sera from 60 suspected asthmatic patients and 18 healthy controls were assayed for sIgE and sIgG4 reactivity against a panel of 70 SPT allergen preparations, and for tIgE. The patients were also assessed by skin prick tests for reactivity to cat, dog, house dust mite and grass allergens. Over 50% of the patients had tIgE levels above the 75th percentile of the controls. 58% of patients and 39% of controls showed sIgE reactivity to ≥1 allergen. The mean number of allergens detected by sIgE was 3.1 in suspected asthma patients and 0.9 in controls. 58% of patients and 50% of controls showed sIgG4 reactivity to ≥1 allergen. The mean number of allergens detected by sIgG4 was 2.5 in patients and 1.7 in controls. For the patients, a strong correlation was observed between clinical SPT reactivity and serum sIgE levels to cat, dog, house dust mite (HDM) and grass allergens. SPT correlations using sIgE/sIgG4 or sIgE/tIgE ratios were not markedly higher. The measurement of serum sIgE by microarray using SPT allergen preparations showed good correlation with clinical SPT reactivity to cat, dog, HDM and grass allergens. This concordance was not improved by measuring tIgE or sIgG4.

Component-Resolved Diagnosis of Hazelnut Allergy in Children

Hazelnuts commonly elicit allergic reactions starting from childhood and adolescence, with a rare resolution over time. The definite diagnosis of a hazelnut allergy relies on an oral food challenge. The role of component resolved diagnostics in reducing the need for oral food challenges in the diagnosis of hazelnut allergies is still debated. Therefore, three electronic databases were systematically searched for studies on the diagnostic accuracy of specific-IgE (sIgE) on hazelnut proteins for identifying children with a hazelnut allergy. Studies regarding IgE testing on at least one hazelnut allergen component in children whose final diagnosis was determined by oral food challenges or a suggestive history of serious symptoms due to a hazelnut allergy were included. Study quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Eight studies enrolling 757 children, were identified. Overall, sensitivity, specificity, area under the curve and diagnostic odd ratio of Cor a 1 sIgE were lower than those of Cor a 9 and Cor a 14 sIge. When the test results were positive, the post-test probability of a hazelnut allergy was 34% for Cor a 1 sIgE, 60% for Cor a9 sIgE and 73% for Cor a 14 sIgE. When the test results were negative, the post-test probability of a hazelnut allergy was 55% for Cor a 1 sIgE, 16% for Cor a9 sIgE and 14% for Cor a 14 sIgE. Measurement of IgE levels to Cor a 9 and Cor a 14 might have the potential to improve specificity in detecting clinically tolerant children among hazelnut-sensitized ones, reducing the need to perform oral food challenges.

Biomarkers of diagnosis and resolution of food allergy

Food allergy is increasing in prevalence, affecting up to 10% of children in developed countries. Food allergy can significantly affect the quality of life and well-being of patients and their families; therefore, an accurate diagnosis is of extreme importance. Some food allergies can spontaneously resolve in 50%-60% of cow's milk and egg-allergic, 20% of peanut-allergic and 9% of tree nut-allergic children by school age. For that reason, food-allergic status should be monitored over time to determine when to reintroduce the food back into the child's diet. The gold-standard to confirm the diagnosis and the resolution of food allergy is an oral food challenge; however, this involves the risk of causing an acute-allergic reaction and requires clinical experience and resources to treat allergic reactions of any degree of severity. In the clinical setting, biomarkers have been used and validated to enable an accurate diagnosis when combined with the clinical history, deferring the oral food challenge, whenever possible. In this review, we cover the tools available to support the diagnosis of food allergies and to predict food allergy resolution over time. We review the latest evidence on different testing modalities and how effective they are in guiding clinical decision making in practice. We also evaluate predictive test cut-offs for the more common food allergens to try and provide guidance on when challenges might be most successful in determining oral tolerance in children.

Accurate Prediction of Peanut Allergy in One-Third of Adults Using a Validated Ara h 2 Cutoff

BACKGROUND

The diagnostic value of peanut components is extensively studied in children, but to a lesser extent in adults with suspected peanut allergy. The use of peanut components in daily practice may reduce the need for double-blind placebo-controlled food challenges (DBPCFCs); however, validation studies are currently lacking.

OBJECTIVE

To evaluate the diagnostic value of (combined) peanut components and validate a previously found Ara h 2 cutoff level with 100% positive predictive value (PPV) in adults with suspected peanut allergy.

METHODS

Adults who underwent a peanut DBPCFC were included: 84 patients from a previous study (2002-2012) and 70 new patients (2012-2019). Specific IgE (sIgE) to peanut extract, Ara h 1, 2, 3, 6, and 8 was measured using ImmunoCAP. Diagnostic value was assessed with an area under the curve (AUC) analysis.

RESULTS

In total, 95 (62%) patients were peanut allergic. sIgE to Ara h 2 and Ara h 6 were the best predictors with an AUC (95% confidence interval) of 0.85 (0.79-0.91) and 0.85 (0.79-0.92), respectively. The Ara h 2 cutoff level with 100% PPV (≥1.75 kU_A/L) was validated in the 70 new patients. Thirty percent of all included patients could be classified correctly as peanut allergic using this validated cutoff level.

CONCLUSION

sIgE to Ara h 2 and Ara h 6 have equally high discriminative ability. Peanut allergy can be predicted accurately in one-third of adults using a validated cutoff level of sIgE to Ara h 2.

[Pitfalls in the diagnostics of food allergies in children and adolescents]

For the diagnostics of food allergies several points need to be considered. Firstly, it is important to recognize the various clinical pictures that can be caused by a food allergy. The assignment to a disease decides which further examinations are necessary and reasonable. In immunoglobulin (Ig) E‑mediated allergies, the detection of sensitization by determining the specific IgE or the prick test in addition to the medical history is an important mainstay of the diagnostics. Crucial is the fact that the detection of a sensitization against an extract from an allergen source only rarely implies an actual allergy. The majority of positive findings are not clinically relevant. The modern procedure of component-resolved allergy diagnostics improves the significance. Nevertheless, the diagnosis can often only be achieved by oral provocation tests. This article points out possible difficulties with the interpretation of the findings.

Component-resolved diagnostics can be useful for identifying hazelnut allergy in Japanese children

BACKGROUND

Cor a 9 and Cor a 14 are effective markers for predicting hazelnut allergy. However, there have been no reports on the component-resolved diagnostics (CRD) of hazelnut allergy using an oral food challenge (OFC) for diagnosis in Asia. We hypothesized that CRD would improve the accuracy of diagnosing hazelnut allergies in Japanese children.

METHODS

We recruited 91 subjects (median age: 7.3 years) who were sensitized to hazelnuts and had performed a hazelnut OFC at the National Hospital Organization Sagamihara National Hospital between 2006 and 2017. All subjects were classified as allergic or asymptomatic to 3 g of hazelnuts. The sIgE levels (hazelnut/Cor a 1/Cor a 8/Cor a 9/Cor a 14/alder pollen) were measured using ImmunoCAP. We aimed to determine the predictive factors of hazelnut allergy.

RESULTS

Nine subjects (10%) were allergic to ≤3 g of hazelnuts. Levels of sIgE for Cor a 9 in hazelnut-allergic subjects were significantly higher than those in asymptomatic subjects (4.47 vs. 0.76 kU_A/L, p = 0.039). Levels of sIgE to alder pollen and Cor a 1 in hazelnut-allergic subjects were significantly lower than those in asymptomatic subjects (<0.10 vs 13.0 kU_A/L, p = 0.004; <0.10 vs 5.03 kU_A/L, p = 0.025). The area under the receiver operating characteristics curve for hazelnut/alder/Cor a 1/Cor a 9 was 0.55/0.78/0.72/0.71, respectively, with p = 0.651/0.006/0.029/0.040, respectively.

CONCLUSIONS

The findings of a high sIgE level for Cor a 9 and a low sIgE level for Cor a 1 can improve the diagnostic accuracy to better identify Japanese children sensitized to hazelnuts.

Baker's Asthma: Is the Ratio of Rye Flour-Specific IgE to Total IgE More Suitable to Predict the Outcome of Challenge Test Than Specific IgE Alone

Usually the diagnosis of baker's asthma is based on specific inhalation challenge with flours. To a certain extent the concentration of specific IgE to flour predicts the outcome of challenge test in bakers. The aim of this study was to evaluate whether the ratio of specific IgE (sIgE) to total IgE (tIgE) improves challenge test prediction in comparison to sIgE alone. Ninety-five bakers with work-related respiratory symptoms were challenged with rye flour. Total IgE, sIgE, and the sIgE/tIgE ratio were determined. Receiver operator characteristic (ROC) plots including the area under the curve (AUC) were calculated using the challenge test as gold-standard. Total IgE and sIgE concentrations, and their ratio were significantly higher in bakers with a positive challenge test than in those with a negative one (p < 0.0001, p < 0.0001, and p = 0.023, respectively). In ROC analysis, AUC was 0.83 for sIgE alone, 0.79 for tIgE, and 0.64 for the ratio. At optimal cut-offs, tIgE, sIgE, and the ratio reached a positive predicted value (PPV) of 95%, 84% and 77%, respectively. In conclusion, calculating the ratio of rye flour-sIgE to tIgE failed to improve the challenge test prediction in our study group.

IgE testing can predict food allergy status in patients with moderate to severe atopic dermatitis

BACKGROUND

Diagnosing food allergy in patients with atopic dermatitis (AD) is complicated by their high rate of asymptomatic sensitization to foods, which can lead to misdiagnosis and unnecessary food avoidance.

OBJECTIVE

We sought to determine whether food-specific (sIgE) or component immunoglobulin (Ig) E levels could predict allergic status in patients with moderate to severe AD and elevated total IgE.

METHODS

Seventy-eight children (median age, 10.7 years) with moderate to severe AD were assessed for a history of clinical reactivity to milk, egg, peanut, wheat, and soy. The IgE levels for each food and its components were determined by ImmunoCAP. The level and pattern of IgE reactivity to each food and its components, and their ratio to total IgE, were compared between subjects who were allergic and tolerant to each food.

RESULTS

Ninety-one percent of subjects were sensitized, and 51% reported allergic reactivity to at least 1 of the 5 most common food allergens. Allergy to milk, egg, and peanut were most common, and IgE levels to each of these foods were significantly higher in the allergic group. Component IgEs most associated with milk, egg, and peanut allergy were Bos d8, Gal d1, and Ara h2, respectively. The ratio of sIgE to total IgE offered no advantage to sIgE alone in predicting allergy.

CONCLUSION

Specific IgE levels and the pattern of IgE reactivity to food components can distinguish AD subjects allergic vs tolerant to the major food allergens and may therefore be helpful in guiding the clinical management of these patients.

Biomarkers in Food Allergy

PURPOSE OF REVIEW

To familiarize the reader with the concept of precision medicine in food allergy by dealing with the current biomarkers for the diagnosis, prognosis, and management of the disease.

RECENT FINDINGS

Many efforts have been devoted in order to characterize reliable biomarkers able to identify specific phenotypes and endotypes in food allergy. Specific IgE (sIgE), sIgE/total IgE ratios, and T cell assays are just a few candidates that have been investigated over time. With the advent of omics sciences, a new era is commencing. A better understanding of pathogenesis of food allergy and mechanisms of action of the different therapeutic options will allow the accurate selection of the appropriate patient. In the near future, advances in technologies and data interpretation will allow a better understanding of the pathogenesis of food allergy and the identification of proper biomarkers for a personalized treatment tailored on the specific patient's profile.

Increased ratio of pollock roe-specific IgE to salmon roe-specific IgE levels is associated with a positive reaction to cooked pollock roe oral food challenge

BACKGROUND

Anaphylaxis and immediate-type fish roe allergies have been reported worldwide, and, in Japan, fish roe is the sixth most common food allergen. No oral food challenges (OFCs) have used pollock roe (PR), which is reported to have high cross-reactivity with salmon roe (SR). Therefore, we administered an OFC using cooked PR to evaluate PR- and SR-specific immunoglobulin E (IgE) levels and allergic reactions in patients with PR sensitivity.

METHODS

This retrospective study evaluating patient characteristics and responses to OFCs was conducted with 10-20 g of cooked PR, between April 2006 and November 2016.

RESULTS

We assessed 51 patients (median age: 6.8 years). All had PR sensitization, 6 (12%) with a history of immediate reactions to PR, and 18 (35%) of immediate reactions to SR. Median PR-specific and SR-specific IgE values were 3.4 kUA/L and 9.9 kUA/L, respectively. Seven patients (14%) had a positive OFC. There was no anaphylaxis. Induced symptoms were mild and included localized urticaria, throat pruritus, intermittent cough, and mild abdominal pain. We treated one patient with mild abdominal pain with oral antihistamines. There were no significant differences in history of immediate reaction to PR and PR-specific IgE titers between OFC-positive and OFC-negative patients, although significant differences were found for PR-specific IgE titers adjusted for SR-specific IgE (p = 0.025) and PR-specific IgE/SR-specific IgE ratio (p = 0.009).

CONCLUSIONS

Increased PR-specific IgE/SR-specific IgE ratio or PR-specific IgE levels adjusted for SR-specific IgE levels were risk factors for OFC positivity.

Comparison of two different assays and the predictive value of allergen components in house dust mite allergy

AIM

In house dust mite (HDM) allergy diagnostics, the IMMULITE, ImmunoCAP and assays for allergen components (nDer p 1 and rDer p 2) are available.

METHODS

Serum sIgE levels were compared and the predictive values for the detection of an early asthmatic response (EAR) were calculated with receiver operating characteristics and a log-logistic regression model.

RESULTS

sIgE levels of IMMULITE and ImmunoCAP were similar (Dermatophagoides pteronyssinus [D. pter.] 47.3 ± 35.7 and 42.9 ± 34.4 kU.l^-1; p = 0.23). ImmunoCAP slgEs exhibited similar accuracy in detecting an EAR, area under the curves (AUCs): D. pter. (0.76); Dermatophagoides farinae (0.79); nDer p 1 (0.69); and rDer p 2 (0.72). At low sIgE concentrations (3.5 kU.l^-1), rDer p 2 was more specific and better predicted an EAR (probability rDer p 2: 62%; D. pter.: 19%).

NUT Co Reactivity - ACquiring Knowledge for Elimination Recommendations (NUT CRACKER) study

BACKGROUND

Ambiguities exist regarding the diagnosis of tree-nut allergy, necessitating either their elimination or the performance of oral food challenges (OFCs).

OBJECTIVE

To examine the coincidences of allergies among tree-nuts and improve diagnostic testing to minimize the need for OFC.

METHODS

Eighty-three patients prospectively evaluated for walnut, pecan, cashew, pistachio, hazelnut, and almond allergy. A history of previous reactions was obtained, and standardized skin prick tests (SPTs) using finely ground tree-nut solution and basophil activation tests (BAT) were performed. Patients underwent OFC for each tree-nut they eliminated and to which a reaction in the previous 2 years was not documented.

RESULTS

While most patients were sensitized to 5-6 tree-nuts, over 50% were allergic to only 1-2 tree-nuts. The highest rate of allergy in sensitized patients was observed for walnut (74.6%) and cashew (65.6%). The rate of co-allergy for most tree-nuts was <30%. Two-thirds of walnut- and cashew-allergic patients were also allergic to pecan and pistachio, respectively, while all pecan- and pistachio-allergic patients were allergic to walnut and cashew, respectively. Receiver-operating characteristic analysis for SPT and BAT was tree-nut dependent and yielded area under the curve (AUC) values ranging from 0.75 to 0.94. Knowledge of coincident allergies in these pairs along with the combination of SPT and BAT correctly distinguished allergic from tolerant patients for walnut (87%), pecan (66%), cashew (71%), and pistachio (79%).

CONCLUSION

The data presented here should assist in differentiating between allergic and tolerant patients, decrease the need for OFC, and allow for appropriate elimination recommendations.

Anti-IgE treatment with oral immunotherapy in multifood allergic participants: a double-blind, randomised, controlled trial

BACKGROUND

Despite progress in single food oral immunotherapy (OIT), there is little evidence concerning the safety and efficacy of treating individuals with multiple food (multifood) allergies. We conducted a pilot study testing whether anti-IgE (omalizumab) combined with multifood OIT benefitted multifood allergic patients.

METHODS

In this blinded, phase 2 clinical trial conducted at Stanford University, 48 participants, aged 4-15 years, with multifood allergies validated by double-blind, placebo-controlled food challenges (DBPCFCs) to their offending foods were block randomized (3:1) to receive multifood OIT to 2-5 foods, together with omalizumab (n=36) or placebo (n=12). Omalizumab or placebo was administered subcutaneously for 16 weeks with OIT starting at week 8; omalizumab or placebo was stopped 20 weeks before exit DBPCFCs (week 36) to determine the primary endpoint: the proportion of participants who passed DBPCFCs to at least 2 of their offending foods. This completed trial is registered with ClinicalTrials.gov, .

FINDINGS

At week 36, a significantly greater proportion of the omalizumab (30/36, 83%) vs. placebo (4/12, 33%) participants passed DBPCFCs to 2 g protein for ≥ 2 of their offending foods (odds ratio (OR): 10, 95% confidence interval (CI): 1·8, 58·3, P=0·004). The same individuals also tolerated 4 g protein of ≥ 2 foods (secondary endpoint, P=0·004). A greater proportion of omalizumab (13/17, 77%) vs. placebo (0/5, 0%) participants passed a DBPCFC to 2 g protein for ≥ 4 of their offending foods (OR: 33, 95% CI: 1·9, ∞, P=0·01). All participants completed the study. There were no serious or severe (≥ grade 3) adverse events.

INTERPRETATION

In multifood allergic patients, omalizumab improves the efficacy of multifood OIT and enables safe and rapid desensitization.

FUNDING

NIH U19 AADCRC and Opportunity Fund, Sean N. Parker Center for Allergy and Asthma Research at Stanford University, Simons Foundation, Myra Reinhard Foundation, FARE Center of Excellence, Department of Pathology, and Department of Pediatrics, Stanford University.

Making the Most of In Vitro Tests to Diagnose Food Allergy

Various in vitro tests assess different aspects of the underlying immune mechanism of IgE-mediated food allergy. Some can be used for diagnostic purposes; specific IgE to allergen extracts is widely available; specific IgE to allergen components is used in most specialist centers, and the basophil activation test is becoming increasingly used clinically. IgE to allergen peptides, T-cell assays, allergen-specific/total IgE ratios, and allergen-specific IgG4/IgE ratios are currently reserved for research. Different factors can modulate the likelihood of IgE-mediated food allergy of a given allergy test result, namely, the patients' age, ethnicity, previous allergic reaction to the identified food, concomitant atopic conditions, and geographical location, and need to be taken into account when interpreting the allergy test results in the clinic. The importance of the specific food, the clinical resources available, and patient preferences are additional aspects that need to be considered when deciding whether an oral food challenge is required to reach an accurate diagnosis of IgE-mediated food allergy.

Diagnosis of Food Allergy

Food allergy diagnosis remains challenging. Most standard methods are unable to differentiate sensitization from clinical allergy. Recognizing food allergy is of utmost importance to prevent life-threatening reactions. On the other hand, faulty interpretation of tests leads to overdiagnosis and unnecessary food avoidances. Highly predictive models have been established for major food allergens based on skin prick testing and food-specific immunoglobulin E but are lacking for most other foods. Although many newer diagnostic techniques are improving the accuracy of food allergy diagnostics, an oral food challenge remains the only definitive method of confirming a food allergy.

Prevalence of Self-reported Allergic Diseases and IgE Levels: A 2010 KNHANES Analysis

PURPOSE

The prevalence of allergic diseases is known to be associated with both demographic and environmental factors. Herein, we aimed to determine significant factors associated with the prevalence of allergic diseases and with total immunoglobulin E (tIgE) and specific immunoglobulin E (sIgE) levels in Korea.

METHODS

We analyzed unweighted data collected by the 2010 Korea National Health and Nutrition Examination Survey for 2,342 subjects who underwent serum tests for tIgE and sIgE to Dermatophagoides farinae, dog, and Blattella germanica, representing a sample of 16,003,645 citizens, by considering the sample weight and stratification.

RESULTS

The overall prevalence of self-reported allergic diseases was 37.6%. The prevalence rates of allergic rhinitis and atopic dermatitis decreased with age, whereas the asthma prevalence was not affected by the age of the subjects. When analyzed according to the type of allergic diseases, the prevalence of self-reported allergic disease was significantly associated with various factors (e.g. age, occupation, living in urban areas, and depression). The tIgE level decreased with age, but later increased. Elevation of tIgE was significantly associated with male sex, type of occupation, obesity, and smoking status. However, the risk factors for the increased sIgE levels to each allergen were quite different. Sensitization to D. farinae was more likely in young subjects, whereas the prevalence of sensitization to B. germanica was significantly higher in subjects with male sex, residing in a house (houses), and with glucose intolerance. Finally, young age and the smoking status were significantly associated with sensitization to dog.

CONCLUSIONS

Various demographic and environmental factors were significantly associated with the prevalence of self-reported allergic diseases and the levels of tIgE and sIgE to D. farinae, B. germanica, and dog in Korea.

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.