Development of a prediction model for severe wheat allergy

The future of food allergy: Challenging existing paradigms of clinical practice

The field of food allergy has seen tremendous change over the past 5-10 years with seminal studies redefining our approach to prevention and management and novel testing modalities in the horizon. Early introduction of allergenic foods is now recommended, challenging the previous paradigm of restrictive avoidance. The management of food allergy has shifted from a passive avoidance approach to active interventions that aim to provide protection from accidental exposures, decrease allergic reaction severity and improve the quality of life of food-allergic patients and their families. Additionally, novel diagnostic tools are making their way into clinical practice with the goal to reduce the need for food challenges and assist physicians in the-often complex-diagnostic process. With all the new developments and available choices for diagnosis, prevention and therapy, shared decision-making has become a key part of medical consultation, enabling patients to make the right choice for them, based on their values and preferences. Communication with patients has also become more complex over time, as patients are seeking advice online and through social media, but the information found online may be outdated, incorrect, or lacking in context. The role of the allergist has evolved to embrace all the above exciting developments and provide patients with the optimal care that fits their needs. In this review, we discuss recent developments as well as the evolution of the field of food allergy in the next decade.

A 60-minute dosing interval is safer than a 30- or 40-minute interval in oral food challenge

BACKGROUND

The interval between antigen ingestion may influence the safety of oral food challenge tests (OFCs), especially in patients with severe food allergies.

METHODS

This retrospective chart review of OFCs eliciting objective reactions to wheat, egg, and milk that were performed between April 2012 and January 2021 evaluated an equivalent number of low-dose OFCs performed at 30-, 40-, or 60-min intervals. To avoid the influence of the potential allergy severity of the patients, the prediction scores of all intervals were matched. We evaluated the total symptom score (TS), total ingested dose, and the proportions of severe reactions (TS ≥ 30) and adrenaline use.

RESULTS

We analyzed 945 OFCs (wheat, n = 186; egg, n = 561; milk, n = 198). The 60-min OFC had significantly lower TS than the 30- and 40-min OFC methods in wheat (p < 0.001 and p = 0.003, respectively), egg (p < 0.001 for both), and milk (p < 0.001 and p = 0.018, respectively). The total dose in the 60-min method was significantly lower than in the 30-min method (p < 0.001 for all). The proportion of severe reaction (TS ≥ 30) in the 60-min method was significantly lower than that in the 30-min method for the egg and milk OFCs (p = 0.001 and p < 0.001, respectively). There was no difference in the rates of adrenaline injection.

CONCLUSIONS

The 60-min interval is safer than 30- or 40-min intervals in wheat, egg, and milk OFCs in patients with a low threshold dose for food allergy.

Emerging Food Allergy Biomarkers

The management of food allergy is complicated by the lack of highly predictive biomarkers for diagnosis and prediction of disease course. The measurement of food-specific IgE is a useful tool together with clinical history but is an imprecise predictor of clinical reactivity. The gold standard for diagnosis and clinical research is a double-blind placebo-controlled food challenge. Improvement in our understanding of immune mechanisms of disease, development of high-throughput technologies, and advances in bioinformatics have yielded a number of promising new biomarkers of food allergy. In this review, we will discuss advances in immunoglobulin measurements, the utility of the basophil activation test, T-cell profiling, and the use of -omic technologies (transcriptome, epigenome, microbiome, and metabolome) as biomarker tools in food allergy.

Development of a prediction model for infants at high risk of food allergy

Background

Identification of risk factors for food allergy (FA) in infants is an active research area. An important reason is to identify optimal target infants for early introduction of specific food antigens. Although eczema has been used for this purpose, multivariable prediction scores have not been reported.

Objective

The aim of this research is to develop a multivariable prediction score for infants at high risk of FA.

Methods

We performed a cross-sectional analysis of a self-administered questionnaire for the parents of 18-month-old children at well-child visits between April 2016 and March 2017 (development dataset) and between April 2017 and March 2018 (validation dataset). We developed and validated the prediction score.

Results

The questionnaire collection rate was 18,549 of 20,198 (92%) in the development dataset and 18,620 of 19,977 (93%) in the validation dataset. Risk factors for FA were being born in August–December, first child, eczema, atopic dermatitis in father and mother, and FA in mother and sibling(s). For identifying infants with FA, the developed multivariable prediction score showed higher discrimination ability (area under the curve [AUC] = 0.75) than focusing on eczema (AUC = 0.70) in the validation dataset. The score was also useful for identifying infants with a history of anaphylaxis (AUC = 0.73) than focusing on eczema (AUC = 0.67) in the validation dataset.

Conclusion

The new prediction score enables more efficient identification of infants at high risk of FA, who may be the optimal target group for the early introduction of specific antigens.

Two Different Composite Markers Predict Severity and Threshold Dose in Peanut Allergy

BACKGROUND

Safe and cost-effective biological surrogate markers to evaluate the severity and threshold dose of peanut allergy (PA) reactions during an oral food challenge (OFC) are lacking.

OBJECTIVE

To evaluate biological markers associated with the severity and threshold dose of an allergic reaction during an OFC in a population of children with PA.

METHODS

Demographic and biological parameters of children with peanut OFC and basophil activation test (BAT) results were collected. Patients were stratified into 2 severity groups (mild-to-moderate and severe) and 2 cumulative threshold dose groups: low (LCTG) ≤100 mg crushed peanut and high >100 mg.

RESULTS

Among the 68 children included, there was a 96% concordance between the OFC and BAT result for the diagnosis of PA. Of the 56 children with a positive OFC and BAT to peanut (median age: 8.8 years), the severity of an allergic reaction and the cumulative threshold dose were not correlated (P = .24). Higher Ara h 2-specific IgE and FcεRI-positive control values were both associated with severe reactions to peanut. Combining these 2 markers led to a 92% sensitivity (84%-97%) and an 82% specificity (71%-89%) for severe reactions in all subjects. For children in the LCTG, a 4-variable composite marker, including age, normalized basophil sensitivity (EC₅₀), and FcεRI- and fMLP-positive control values, resulted in a 97% sensitivity (89%-99%) and 61% specificity (49%-71%).

CONCLUSION

Distinct composite markers including BAT allergen-specific and non-allergen-specific parameters appear to be associated with severity and cumulative threshold dose in children with PA.

Slow low-dose oral immunotherapy: Threshold and immunological change

BACKGROUND

We examined the feasibility, efficacy and safety of slow low-dose oral immunotherapy (SLOIT) for egg, milk, wheat allergies, with accepted severity-stratified initial and maintenance doses.

METHODS

Children with food allergies defined by low-dose oral food challenges (LD-OFCs) to hen's egg (cumulative protein dose up to 983 mg, n = 133), cow's milk (287 mg, n = 50), and wheat (226 mg, n = 45) were recruited. Participants were divided into two groups [SLOIT and control (complete avoidance]) based on their preferences. Participants who selected SLOIT were instructed to take the safe dose daily, with monthly increases, aiming to increase the dose by 10 times in one year. The primary outcome was the proportion of participants who passed the LD-OFCs following 1 year of therapy.

RESULTS

The participants in SLOIT group ingested their antigen 92.9% of the therapy's day on average. The proportion of participants who passed LD-OFCs was 35.9% (61/170) in the SLOIT group and 8.7% (4/46) in the control group (P < .001); no large differences were observed among allergens. Among the subjects who failed LD-OFCs, the median change in the total dose in the LD-OFC was 235% (interquartile range: 100%-512%) in the SLOIT group and 100% (42%-235%) in the control group (P < .001). Provoked allergic symptoms were observed in only 0.58% (280/48,486) per programmed intake and approximately 50% of the SLOIT group did not experience any obvious allergic symptoms throughout therapy.

CONCLUSIONS

SLOIT showed significant feasibility, efficacy and safety, providing a promising option to manage patients with severe food allergies.

Exercise-induced allergic reactions on desensitization to wheat after rush oral immunotherapy

BACKGROUND

The effect of oral immunotherapy (OIT) on wheat allergy is promising in terms of the potential to obtain desensitization; however, the frequency of exercise-induced allergic reactions on desensitization (EIARDs) and the associated risk factors remain to be determined.

METHODS

Twenty-five patients underwent rush OIT for wheat allergy, and 21 achieved the full-dose intake of wheat products (5 g of wheat protein). Exercise-provocation tests were repeatedly performed after the ingestion of a full-dose wheat product. The time-course of the levels of the specific IgEs (sIgE) to wheat extract, total gliadin, deamidated gliadin, recombinant gliadin components (α/β-, γ- and ω-5-), and glutenin (high and low molecular weight) components was analyzed using ImmunoCAP^® , ELISA, or IgE immunoblotting.

RESULTS

Fourteen patients (66.7%) were diagnosed as EIARD+, which remained 5 years after rush OIT in 11 patients (52.4%). There were no differences in the clinical backgrounds of the EIARD+ and EIARD- patients. However, EIARD+ patients showed significantly higher sIgE levels to all gliadin and glutenin components than EIARD- patients before OIT. The sIgE levels to each component decreased equally after 1 and 2 years of OIT. On IgE immunoblotting, sera from all patients reacted to the multiple gluten bands, and some reacted to the water-soluble bands. The intensity of all IgE-reactive bands also became equally lighter after OIT.

CONCLUSIONS

EIARDs were frequently observed and remained for a long period after successful OIT for wheat allergy. None of the specific wheat components were found to contribute to EIARDs.

Innovation in Food Challenge Tests for Food Allergy

PURPOSE OF REVIEW

This review incorporates findings from studies of oral food challenges (OFC) over the last decade and highlights the latest innovations and understanding of the procedure.

RECENT FINDINGS

PRACTALL guidelines are widely used in OFC research, but there is still no international consensus on the OFC protocol in clinical practice. Guidelines for performing OFC in clinical practice have been updated to include oral food challenges for infants. There have been advances in predictive models for outcomes and severity of reaction during OFC that take into account multiple clinical data as well as newer laboratory modalities. Low-dose OFC and eliciting threshold dose determination are being examined for additional diagnostic and therapeutic use in the management of food allergy. Quality-of-life considerations have also been reviewed, as well as post-OFC assessment and care. The OFC remains an important diagnostic tool in the management of food allergy and in clinical research. Advances in the field should improve safety and broaden the clinical applications of this essential procedure.

Food-Induced Anaphylaxis: an Update

PURPOSE OF REVIEW

This review aims to provide an update of recent advances in the epidemiology, clinical features and diagnosis, and management of food-induced anaphylaxis (FIA).

RECENT FINDINGS

Food allergy prevalence and FIA rates continue to rise, but FIA fatalities are stable. Basophil and mast cell activation tests promise more accurate identification of food triggers. Oral, sublingual, and epicutaneous immunotherapy can desensitize a significant portion of subjects. Epinephrine use for FIA remains sub-optimal. As the burden of food allergy continues to increase, it appears that the corresponding increase in research focused on this epidemic is beginning to bear fruit. The stable number of FIA fatalities in the face of an ongoing epidemic indicates lives have already been saved. The emergence of new diagnostic tests and interventional therapies may transform the management of FIA in the coming years.

Development of a tool predicting severity of allergic reaction during peanut challenge

BACKGROUND

Reliable prognostic markers for predicting severity of allergic reactions during oral food challenges (OFCs) have not been established.

OBJECTIVE

To develop a predictive algorithm of a food challenge severity score (CSS) to identify those at higher risk for severe reactions to a standardized peanut OFC.

METHODS

Medical history and allergy test results were obtained for 120 peanut allergic participants who underwent double-blind, placebo-controlled food challenges. Reactions were assigned a CSS between 1 and 6 based on cumulative tolerated dose and a severity clinical indicator. Demographic characteristics, clinical features, peanut component IgE values, and a basophil activation marker were considered in a multistep analysis to derive a flexible decision rule to understand risk during peanut of OFC.

RESULTS

A total of 18.3% participants had a severe reaction (CSS >4). The decision rule identified the following 3 variables (in order of importance) as predictors of reaction severity: ratio of percentage of CD63^hi stimulation with peanut to percentage of CD63^hi anti-IgE (CD63 ratio), history of exercise-induced asthma, and ratio of forced expiratory volume in 1 second to forced vital capacity (FEV₁/FVC) ratio. The CD63 ratio alone was a strong predictor of CSS (P < .001).

CONCLUSION

The CSS is a novel tool that combines dose thresholds and allergic reactions to understand risks associated with peanut OFCs. Laboratory values (CD63 ratio), along with clinical variables (exercise-induced asthma and FEV₁/FVC ratio) contribute to the predictive ability of the severity of reaction to peanut OFCs. Further testing of this decision rule is needed in a larger external data source before it can be considered outside research settings.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02103270.