Cracking the egg: An insight into egg hypersensitivity

Hypersensitivity to the chicken egg is a widespread disorder mainly affecting 1-2% of children worldwide. It is the second most common food allergy in children, next to cow's milk allergy. Egg allergy is mainly caused by hypersensitivity to four allergens found in the egg white; ovomucoid, ovalbumin, ovotransferrin and lysozyme. However, some research suggests the involvement of allergens exclusively found in the egg yolk such as chicken serum albumin and YGP42, which may play a crucial role in the overall reaction. In egg allergic individuals, these allergens cause conditions such as itching, atopic dermatitis, bronchial asthma, vomiting, rhinitis, conjunctivitis, laryngeal oedema and chronic urticaria, and anaphylaxis. Currently there is no permanent cure for egg allergy. Upon positive diagnosis for egg allergy, strict dietary avoidance of eggs and products containing traces of eggs is the most effective way of avoiding future hypersensitivity reactions. However, it is difficult to fully avoid eggs since they are found in a range of processed food products. An understanding of the mechanisms of allergic reactions, egg allergens and their prevalence, egg allergy diagnosis and current treatment strategies are important for future studies. This review addresses these topics and discusses both egg white and egg yolk allergy as a whole.

Nitration of β-Lactoglobulin but Not of Ovomucoid Enhances Anaphylactic Responses in Food Allergic Mice

Background

We revealed in previous studies that nitration of food proteins reduces the risk of de novo sensitization in a murine food allergy model. In contrast, in situations with preformed specific IgE antibodies, in vitro experiments suggested an increased capacity of effector cell activation by nitrated food proteins.

Objective

The aim of this study was to investigate the influence of protein nitration on the effector phase of food allergy.

Design

BALB/c mice were immunized intraperitoneally (i.p.) with the milk allergen β-lactoglobulin (BLG) or the egg allergen ovomucoid (OVM), followed by intragastric (i.g.) gavages to induce a strong local inflammatory response and allergen-specific antibodies. Subsequently, naïve and allergic mice were intravenously (i.v.) challenged with untreated, sham-nitrated or nitrated BLG or OVM. Anaphylaxis was monitored by measuring core body temperature and determination of mouse mast cell protease-1 (mMCP-1) levels in blood.

Results

A significant drop of body temperature accompanied with significantly elevated concentrations of the anaphylaxis marker mMCP-1 were only observed in BLG allergic animals challenged with nitrated BLG and not in OVM allergic mice challenged with nitrated OVM. SDS-PAGE and circular dichroism analysis of the differentially modified allergens revealed an effect of nitration on the secondary protein structure exclusively for BLG together with enhanced protein aggregation.

Conclusion

Our data suggest that nitration affects differently the food allergens BLG and OVM. In the case of BLG, structural changes favored dimerization possibly explaining the increased anaphylactic reactivity in BLG allergic animals.

Randomized trial of peanut consumption in infants at risk for peanut allergy

BACKGROUND

The prevalence of peanut allergy among children in Western countries has doubled in the past 10 years, and peanut allergy is becoming apparent in Africa and Asia. We evaluated strategies of peanut consumption and avoidance to determine which strategy is most effective in preventing the development of peanut allergy in infants at high risk for the allergy.

METHODS

We randomly assigned 640 infants with severe eczema, egg allergy, or both to consume or avoid peanuts until 60 months of age. Participants, who were at least 4 months but younger than 11 months of age at randomization, were assigned to separate study cohorts on the basis of preexisting sensitivity to peanut extract, which was determined with the use of a skin-prick test--one consisting of participants with no measurable wheal after testing and the other consisting of those with a wheal measuring 1 to 4 mm in diameter. The primary outcome, which was assessed independently in each cohort, was the proportion of participants with peanut allergy at 60 months of age.

RESULTS

Among the 530 infants in the intention-to-treat population who initially had negative results on the skin-prick test, the prevalence of peanut allergy at 60 months of age was 13.7% in the avoidance group and 1.9% in the consumption group (P<0.001). Among the 98 participants in the intention-to-treat population who initially had positive test results, the prevalence of peanut allergy was 35.3% in the avoidance group and 10.6% in the consumption group (P=0.004). There was no significant between-group difference in the incidence of serious adverse events. Increases in levels of peanut-specific IgG4 antibody occurred predominantly in the consumption group; a greater percentage of participants in the avoidance group had elevated titers of peanut-specific IgE antibody. A larger wheal on the skin-prick test and a lower ratio of peanut-specific IgG4:IgE were associated with peanut allergy.

CONCLUSIONS

The early introduction of peanuts significantly decreased the frequency of the development of peanut allergy among children at high risk for this allergy and modulated immune responses to peanuts. (Funded by the National Institute of Allergy and Infectious Diseases and others; ClinicalTrials.gov number, NCT00329784.).

[A case of eosinophilic esophagogastroenteritis which developed after rush oral immunotherapy for egg allergy]

Rush oral immunotherapy was provided to a 9 year old boy suffering from egg allergy. The patient reached the goal of one boiled egg daily on day 22 of treatment. He was discharged from the hospital the following day, with the maintenance dose of one whole egg to be taken daily. However, the patient began to experience abdominal pain and vomiting after ingestion of egg approximately one day after discharge. Blood tests revealed a remarkable increase in eosinophils in peripheral blood, and we reduced the patient's intake of egg. The patient's condition did not improve, and he gradually started to lose weight. Maintenance dosing was stopped completely on day 38. An endoscopic biopsy of the mucosa lining from the esophagus to the duodenum was performed on day 45. The results confirmed prominent diffuse eosinophilic infiltration of the entire upper gastrointestinal tract. The patient was finally diagnosed with eosinophil esophagogastroenteritis. While this condition is rare, it should be considered in future cases of persistent gastrointestinal symptoms during food allergy immunotherapy.

Comprehensive Review of Current Knowledge on Egg Oral Immunotherapy

Oral immunotherapy (OIT) is an attractive strategy for active treatment of IgE-mediated food allergy. Multiple egg OIT studies have been published to date, but many are uncontrolled. Furthermore, interpretation of the results is difficult because of significant heterogeneity in design, aims, and population. Most studies have demonstrated the potential of egg OIT to induce desensitization, albeit to different extents (0%-100% of patients). However, few studies have explored the capacity of OIT to maintain tolerance, that is, enabling the patient to continue consuming egg after suspension of therapy. Nowadays, 28% to 75% of patients maintain tolerance after 1 to 3 months of their elimination diet. Adverse effects are the main drawback of this treatment, which is still not recommended in routine practice. Adverse reactions are not reported homogeneously, with the result that it is difficult to properly assess outcomes. The overall impression is that adverse reactions affect most patients and tend to be frequent, although of mild to moderate severity. Nevertheless, severe events such as anaphylaxis or eosinophilic esophagitis may also occur. Immunological changes resulting from egg OIT, for example, the decrease in the size of the skin prick test wheal and the levels of egg white sIgE and a significant early increase in egg white sIgG4, have been reported. Several areas of egg OIT remain unclear, including patient selection, materials used, dosing schedule, treatment duration, long-term maintained effectiveness, requirements for implementation in clinical practice, influence on quality of life, and cost-effectiveness of treatment. In this review, we provide an in-depth examination of methodological differences between studies in order to understand the diversity in the efficacy and safety results of the procedures used in egg OIT.

Attenuation of allergic immune response phenotype by mannosylated egg white in orally induced allergy in BALB/c mice

Food allergies are attributed to an imbalance in immune response to ubiquitous antigens. A previous study demonstrated that mannose glycation (mannosylation) of ovalbumin decreased allergenicity in vivo. The proposed research targets mannosylation of various common allergens that may help prevent food allergy. Balb/c mice (n = 8) were sensitized toxin egg white, peanut, and whey and treated with mannosylated forms of the test antigens. Glucosylated peanut and cholera toxins were used as controls. Allergic status was assessed as clinical signs, serum histamine, mouse mast cell protease (MMCP), antibody activity, cytokines, and T regulatory cells (T-regs). Significant preventative effects were observed with mannosylated egg white treatment such as reduced clinical signs, histamine, MMCP, specific G, G1, and E antibody activities, and IL-4 and increased IL-10 and CD25(+) Foxp3(+) cells. Other groups did not differ significantly. It was concluded that mannosylated egg white provides a powerful tool to prevent allergic phenotypes with possible relevance to control human egg allergy.

Screening for hen's egg and chicken meat specific IgE antibodies in Saudi patients with allergic disorders

BACKGROUND

Allergy to hen's egg and meat contributes significantly to the manifestations of food allergy all over the world.

OBJECTIVES

This study was performed to assess the presence of hen's egg and meat specific IgE antibodies among patients investigated for various allergic disorders.

METHODS

This is a retrospective study performed at King Khalid University Hosptial, Riyadh. Data from 421 patients with allergic disorders screened for food specific IgE antibodies between January 2009 and March 2011 were analyzed. Sixty (14.25%) patients including 42 males and 18 females with the mean age (sd) of 7.5 (7.4) years were found to have specific IgE antibodies against hen's egg and chicken meat. There were 56 (93.3%) children and 4 (6.7%) adult patients. Specific IgE antibodies were measured by radioallergosorbent test (RAST) using Pharmacia ImmunoCAP 250 analyzer.

RESULTS

Atopic dermatitis was the most common (55%) clinical condition. Out of the total 60 patients harboring hen's egg and chicken meat specific IgE antibodies high levels of egg white, yolk and chicken meat specific IgEs were detected in 58 (96.6%), 37 (61.6%) and 6 (10%) patients respectively. Both the egg white and yolk antibodies coexisted in 35 (58.3%) patients.

CONCLUSION

Sensitization against hen's egg was higher compared to the chicken meat. Egg white sensitization higher than the egg yolk particularly in Saudi children with food related allergic disorders.

Agreement between the skin prick test and specific serum IgE for egg white and cow's milk allergens in young infant with atopic dermatitis

BACKGROUND

The skin prick test (SPT) for detecting atopic sensitization is not preferred in young infants with atopic dermatitis (AD) because of concerns about poor skin reactivity. This study aimed to evaluate whether the results of SPT agreed well with those of specific serum immunoglobulin E (sIgE) antibody test in young infants with AD.

METHODS

This study included 2,077 eligible infants (age, <12 months) with AD who were tested by either SPT or sIgE between 2007 and 2011. Among them, 199 infants tested for egg white (EW) and 192 infants tested for cow's milk (CM), by both SPT and sIgE on the same day were identified and reviewed retrospectively. Kappa statistics and tests for equal kappa statistics were used to evaluate the agreement between the SPT and sIgE.

RESULTS

The mean wheal diameter and the allergen-to-histamine ratio of SPT showed substantial agreement with those of sIgE for EW (κ = 0.62, 0.69) and CM (κ = 0.34, 0.47). The agreement for EW was significantly higher <6-month-old than in ≥6-month-old infants (κ = 0.79 vs. 0.54, P = 0.02), and that for CM was similar (P = 0.60). The mean wheal diameters for EW and CM were evenly distributed, and did not show increasing trends regardless of age in months (Ptrend = 0.13 and 0.06, respectively).

CONCLUSIONS

The results of SPT agreed well with those of sIgE. This finding provides a rationale for using SPT, and suggests that SPT can be used along with sIgE to detect food sensitization in young infants with AD.

Laboratorial characteristics of patients with diarrhoea suffering from egg white allergy

BACKGROUND

Egg allergy is associated with diarrhoeal symptoms. However, the mechanism underlying allergic diarrhoea remains unclear.

OBJECTIVE

To determine whether egg white-specific IgE antibodies coexist with egg white-specific IgG antibodies in patients with egg allergy featuring diarrhoeal symptoms, and whether there is any relationship between these two antibody types.

METHODS

A total of 89 patients with egg allergy featuring diarrhoeal symptoms (average age, 23.2 years; range, 1-78 years), all of whom tested positive for egg white-specific IgG, were enrolled in this study. The concentration of total IgE, egg white-specific IgE and number of eosinophils in the serum were determined.

RESULTS

Among the 89 egg white allergic patients tested, 49 (55.1%) patients showed high reactivity to egg white-specific IgG, 48 (53.9%) patients had elevated serum total IgE levels, and 25 (28.1%) patients had elevated absolute eosinophil numbers. Out of the 89 egg white allergic patients, 25 showed elevated egg white-specific IgE antibody levels. Of the 25 patients who were positive for egg white-specific IgE antibody, 21 presented high sensitive reaction to egg white-specific IgG, three presented moderate sensitive reaction to egg white-specific IgG, and one presented mild sensitive reaction to egg white-specific IgG. A moderate correlation between egg white-specific IgG and egg white-specific IgE, egg white-specific IgG and absolute eosinophil number was found in the egg white allergic patients (r=0.438, P=0.000; r=0.322, P=0.002). Egg white-specific IgE levels varied in different age groups; the egg white-specific IgE concentration of younger patients (age≤18 years, mean rank 54.29) was significantly higher than that of the adult patients (age>18 years, mean rank 34.61) (Z=-3.629, P=0.000).

CONCLUSION

Egg white-specific IgE antibody could coexist with egg white-specific IgG antibody in patients suffering from egg white allergy. Aberrant changes in the concentration of egg white-specific IgE antibody were associated with the presence of egg white-specific IgG antibody.

Food-specific serum immunoglobulin E measurements in children presenting with food allergy

BACKGROUND

In children with food allergy, multiple food-specific serum IgE levels to common food allergens are frequently measured.

OBJECTIVE

To compare food-specific serum IgE measurements among common food allergens in children with food allergy to determine the characteristics of the measurements, their ability to discriminate between foods associated and not associated with a presenting clinical reaction, and their change over time.

METHODS

A retrospective analysis was conducted of food-specific serum IgE to cow's milk, egg white and yolk, peanuts, almond, and soy, for up to 3 subsequent measurements, in 291 children with food allergy. A food-specific serum IgE level lower than 0.35 kU/L was considered a negative measurement. The correlation of IgE measurements with presenting symptoms was conducted for each food in 172 children.

RESULTS

Of 1,312 food-specific serum IgE measurements, 69.8% were positive. The median (interquartile range) IgE level for foods associated with the presenting complaint was 7.3 kU/L (2.7-31) and that for foods not associated with a clinical complaint was 2.2 kU/L (0.38-13). The difference was statistically significant (P = .01) only for cow's milk. Specific IgE levels were highest for peanuts, followed by cow's milk, eggs, soy, and almonds, and trended upward over time.

CONCLUSION

In children presenting with clinical symptoms of a reaction to a food allergen, measurements of food-specific serum IgE to other common food allergens are commonly positive. An increase in food-specific serum IgE occurs over time.

IgE-mediated food allergy in children

Food allergy is a serious health issue affecting roughly 4% of children, with a substantial effect on quality of life. Prognosis is good for the most frequent allergens with almost all children outgrowing their allergy. However, the long-term implications for disease burden are substantial for children with persistent allergies (eg, peanuts, tree nuts, fish, and shellfish) and for those with high concentrations of milk, egg, and wheat IgE. Antigen avoidance has been the time-honoured approach both for prevention and treatment. However, findings from studies done in the past 5 years show that early contact with food can induce tolerance and desensitisation to foods. We review the epidemiology, natural history, and management of food allergy, and discuss the areas of controversy and future directions in research and clinical practice.

Combined effect of glycation and sodium carbonate-bicarbonate buffer concentration on IgG binding, IgE binding and conformation of ovalbumin

BACKGROUND

Ovalbumin (OVA) is a major allergen in hen egg. During thermal processing, reducing sugars contained in the hen egg white might easily undergo glycation with OVA, but few studies have been conducted on its corresponding immunoreactivity changes. The aim of the present study was to assess changes of the antigenicity, potential allergenicity and conformation of OVA after glycation in a wet-thermal processing system under different concentrations of sodium carbonate-bicarbonate buffer.

RESULTS

IgE binding of the glycated OVA was increased after glycation, and the higher the sodium carbonate-bicarbonate buffer concentration, the higher the IgE binding capacity. The increase in IgE binding of OVA corresponded well with the disruption of the disulfide bond, which exposed the epitopes initially buried. Antigenicity of the glycated OVA was increased, and the amount of the increase varied among samples treated under different buffer concentrations.

CONCLUSION

Glycation increased the allergenic potential for OVA, with the amount of increase varying with different sodium carbonate-bicarbonate buffer concentrations.

Interpretation of food specific immunoglobulin E levels in the context of total IgE

BACKGROUND

Food specific immunoglobulin E (IgE) (fsIgE) cut points are used in the evaluation of food allergies. Concomitant measurement of total IgE (tIgE) is traditionally not obtained. We anecdotally observed elevations in fsIgE mirroring tIgE increases, which may confound accurate interpretation.

OBJECTIVE

To determine whether changes in tIgE were associated with fsIgE and whether predictions of fsIgE could be formulated based on tIgE.

METHODS

We studied children younger than 18 years who had both tIgE and fsIgE (egg, n = 136; milk, n = 123; peanut, n = 201; soy, n = 55) obtained simultaneously on 1 or more occasion between January 2008 and February 2011. After institutional review board approval, natural log-transformed (ln) tIgE and fsIgE levels were analyzed using univariate and multivariate regression models to assess associations and predict fsIgE using tIgE and other covariates.

RESULTS

Soy IgE levels were strongly correlated (ρ = 0.85, P < .001), whereas egg, milk, and peanut IgE levels were substantially correlated (ρ = 0.69, 0.69, and 0.66, respectively, P < .001) with tIgE. A 1-unit increase in ln(tIgE) was significantly correlated with unit increases in ln(egg IgE) (0.77), ln(milk IgE) (0.84), ln(peanut IgE) (0.87), and ln(soy IgE) (0.89) (P < .001). The ln(tIgE)-based univariate models could predict fsIgE in the validation data with strong (soy) and substantial (egg, milk, and peanut) predictive ability (P < .001).

CONCLUSION

Our study found significant and parallel relationships between tIgE and fsIgE levels to egg, milk, peanut, and soy. It underscores the importance of examining fsIgE levels in context of tIgE while making diagnostic and management decisions in children with food allergies.

Early regular egg exposure in infants with eczema: A randomized controlled trial

BACKGROUND

Observational studies suggest that early regular ingestion of allergenic foods might reduce the risk of food allergy.

OBJECTIVE

We sought to determine whether early regular oral egg exposure will reduce subsequent IgE-mediated egg allergy in infants with moderate-to-severe eczema.

METHODS

In a double-blind, randomized controlled trial infants were allocated to 1 teaspoon of pasteurized raw whole egg powder (n = 49) or rice powder (n = 37) daily from 4 to 8 months of age. Cooked egg was introduced to both groups after an observed feed at 8 months. The primary outcome was IgE-mediated egg allergy at 12 months, as defined based on the results of an observed pasteurized raw egg challenge and skin prick tests.

RESULTS

A high proportion (31% [15/49]) of infants randomized to receive egg had an allergic reaction to the egg powder and did not continue powder ingestion. At 4 months of age, before any known egg ingestion, 36% (24/67) of infants already had egg-specific IgE levels of greater than 0.35 kilounits of antibody (kUA)/L. At 12 months, a lower (but not significant) proportion of infants in the egg group (33%) were given a diagnosis of IgE-mediated egg allergy compared with the control group (51%; relative risk, 0.65; 95% CI, 0.38-1.11; P = .11). Egg-specific IgG4 levels were significantly (P < .001) greater in the egg group at both 8 and 12 months.

CONCLUSION

Induction of immune tolerance pathways and reduction in egg allergy incidence can be achieved by early regular oral egg exposure in infants with eczema. Caution needs to be taken when these high-risk infants are first exposed to egg because many have sensitization already by 4 months of age.

Heated allergens and induction of tolerance in food allergic children

Food allergies are one of the first manifestations of allergic disease and have been shown to significantly impact on general health perception, parental emotional distress and family activities. It is estimated that in the Western world, almost one in ten children have an IgE-mediated allergy. Cow's milk and egg allergy are common childhood allergies. Until recently, children with food allergy were advised to avoid all dietary exposure to the allergen to which they were sensitive, in the thought that consumption would exacerbate their allergy. However, recent publications indicate that up to 70% of children with egg allergy can tolerate egg baked in a cake or muffin without apparent reaction. Likewise, up to 75% of children can tolerate baked goods containing cow's milk, and these children demonstrate IgE and IgG4 profiles indicative of tolerance development. This article will review the current literature regarding the use of heated food allergens as immunotherapy for children with cow's milk and egg allergy.

Evaluation of the luciferase assay-based in vitro elicitation test for serum IgE

BACKGROUND

An in vitro elicitation test employing human high-affinity IgE receptor-expressing rat mast cell lines appears to be a useful method for measuring mast cell activation using a patient's IgE and an allergen; however, such cell lines are sensitive to human complements in the serum. We have recently developed a new luciferase-reporting mast cell line (RS-ATL8) to detect IgE crosslinking-induced luciferase expression (EXiLE) with relatively low quantities of serum IgE.

METHODS

A total of 30 patients suspected of having egg white (EW) allergy were subjected to an oral food challenge (OFC) test; then, the performances of EW-specific serum IgE (CAP-FEIA), EW-induced degranulation, and EXiLE responses in RS-ATL8 cells were compared using receiver-operating characteristic (ROC) curve analysis. The patients' sera were diluted to 1 : 100, which causes no cytotoxicity when sensitizing the RS-ATL8 cells for the degranulation and EXiLE tests.

RESULTS

The area under the ROC curves was highest in the EXiLE test (0.977), followed by CAP-FEIA (0.926) and degranulation (0.810). At an optimal cutoff range (1.648-1.876) calculated from the ROC curve of the EXiLE test, sensitivity and specificity were 0.944 and 0.917, respectively. A 95% positive predictive value was given at a cutoff level of 2.054 (fold increase in luciferase expression) by logistic regression analysis.

CONCLUSIONS

In contrast to in vivo tests, the EXiLE test appears to be a useful tool in diagnosing patients suspected of having IgE-dependent EW allergy without the risk of severe systemic reactions.

Oral immunotherapy for treatment of egg allergy in children

BACKGROUND

For egg allergy, dietary avoidance is the only currently approved treatment. We evaluated oral immunotherapy using egg-white powder for the treatment of children with egg allergy.

METHODS

In this double-blind, randomized, placebo-controlled study, 55 children, 5 to 11 years of age, with egg allergy received oral immunotherapy (40 children) or placebo (15). Initial dose-escalation, build-up, and maintenance phases were followed by an oral food challenge with egg-white powder at 10 months and at 22 months. Children who successfully passed the challenge at 22 months discontinued oral immunotherapy and avoided all egg consumption for 4 to 6 weeks. At 24 months, these children underwent an oral food challenge with egg-white powder and a cooked egg to test for sustained unresponsiveness. Children who passed this challenge at 24 months were placed on a diet with ad libitum egg consumption and were evaluated for continuation of sustained unresponsiveness at 30 months and 36 months.

RESULTS

After 10 months of therapy, none of the children who received placebo and 55% of those who received oral immunotherapy passed the oral food challenge and were considered to be desensitized; after 22 months, 75% of children in the oral-immunotherapy group were desensitized. In the oral-immunotherapy group, 28% (11 of 40 children) passed the oral food challenge at 24 months and were considered to have sustained unresponsiveness. At 30 months and 36 months, all children who had passed the oral food challenge at 24 months were consuming egg. Of the immune markers measured, small wheal diameters on skin-prick testing and increases in egg-specific IgG4 antibody levels were associated with passing the oral food challenge at 24 months.

CONCLUSIONS

These results show that oral immunotherapy can desensitize a high proportion of children with egg allergy and induce sustained unresponsiveness in a clinically significant subset. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00461097.).

Outcome of oral provocation test in egg-sensitive children receiving semi-fat hard cheese Grana Padano PDO (protected designation of origin) containing, or not, lysozyme

PURPOSE

Lysozyme, obtained from egg white, is a potential food allergen used in the dairy industry to prevent late blowing of the loaf caused by the outgrowth of clostridial spores (Cl. butyricum and Cl. tyrobutyricum) during cheese aging. The aim of this study was to evaluate the possible correlation between egg protein allergy in pediatric age and sensitization to egg lysozyme, used for the preparation of Grana Padano cheese.

METHODS

The tolerability of Grana Padano cheese has been evaluated in pediatric patients allergic to egg proteins through an oral provocation test with increasing amounts of cheese containing, or not, lysozyme at 12 and 24 months of aging.

RESULTS

When lysozyme-sensitized children received 12-months aged and lysozyme-containing cheese, several immediate and late adverse reactions such as itching, abdominal pain, vomiting, nausea, dermatitis, rhinitis, bronchial asthma, urticaria, and angioedema were seen in 5 out of 21 subjects; only 1 out of 21 children showed an adverse reaction after challenge with 24-months-ripened lysozyme-containing cheese.

CONCLUSIONS

There is a possible relationship between the severity of allergic reactions and the lysozyme-specific IgE level in blood. In particular vomiting, hypotension, and abdominal pain were present when IgE level was higher than 7 kU/L. A ripening time of 24 months may reduce allergy problems when lysozyme-containing cheese is given to sensitized subjects, probably due to the hydrolysis of antigenic epitopes during aging.

Comparison of irritatant reactions between using lyophilized and commercial food allergen extracts in atopy patch tests in a normal population

BACKGROUND

Several authors have investigated the use of the atopy patch tests (APT) for the diagnosis of non-IgE mediated food allergy, primarily in patients with atopic dermatitis and digestive disorders. However, one of the difficulties in atopy patch testing is the lack of standardization. Several commercial APTs containing freeze-dried food extracts are now available, but their diagnostic accuracy is still largely undefined. The objective of this study is to evaluate the irritant reactions and safety of atopy patch tests in healthy subjects by using lyophilized and commercial food allergen extracts.

METHODS

A cross-sectional study was carried out in healthy volunteers. Atopy patches using lyophilized and commercial allergens, including cow's milk, egg, wheat, soy and shrimp, were assessed. Additionally, commercial extracts of house dust mite (D. pteronyssinus 10,000 AU/ml, D. farinae 10,000 AU/ml) and American cockroach were also evaluated.

RESULTS

Eighteen healthy volunteers (13 women, median age 26 years) were enrolled. All APT results, both from using lyophilized and commercial allergen extracts, showed no reactions. There were no systemic allergic reactions or irritant reactions observed.

CONCLUSION

APTs using lyophilized and commercial food allergen extracts and commercial extracts of house dust mite and American cockroach showed no irritant reactions in Thai non-atopic subjects.

Identification of an IgE reactive peptide in hen egg riboflavin binding protein subjected to simulated gastrointestinal digestion

Riboflavin binding protein (RfBP) is a minor protein in hen egg; its potential involvement in egg allergy has seldom been studied. The aim of this work was to investigate the IgE binding capacity of RfBP before and after simulated gastrointestinal digestion. It was shown that digestion of RfBP mainly occurred during the gastric phase. The protein fragments resulting from the subsequent duodenal phase remained linked through disulfide bonds. Both the intact protein and its digests were subjected to inhibition ELISA with sera obtained from patients allergic to egg. The results revealed significant IgE binding to intact RfBP, whereas the digests showed reduced but substantial IgE binding levels, with serum-to-serum variability. The RfBP digests were then subjected to immunoblot with allergic patients' sera, and the IgE-reactive peptides were further analyzed by MALDI-TOF/TOF mass spectrometry for sequence determination. The RfBP sequence 41-84 was identified as a novel IgE binding peptide in patients allergic to egg.

Role of specific IgE and skin-prick testing in predicting food challenge results to baked egg

Previous studies suggest that children with egg allergy may be able to tolerate baked egg. Reliable predictors of a successful baked egg challenge are not well established. We examined egg white-specific IgE levels, skin-prick test (SPT) results, and age as predictors of baked egg oral food challenge (OFC) outcomes. We conducted a retrospective chart review of children, aged 2-18 years, receiving an egg white-specific IgE level, SPT, and OFC to baked egg from 2008 to 2010. Fifty-two oral baked egg challenges were conducted. Of the 52 challenges, 83% (n = 43) passed and 17% (n = 9) failed, including 2 having anaphylaxis. Median SPT wheal size was 12 mm (range, 0-35 mm) for passed challenges and 17 mm (range, 10-30 mm) for failed challenges (p = 0.091). The negative predictive value for passing the OFC was 100% (9 of 9) if SPT wheal size was <10 mm. Median egg white-specific IgE was 2.02 kU/L (range, <0.35-13.00 kU/L) for passed challenges and 1.52 kU/L (range, 0.51-6.10 kU/L) for failed challenges (p = 0.660). Receiver operating characteristic (ROC) curve analysis for SPT revealed an area under the curve (AUC) of 0.64. ROC curve analysis for egg white-specific IgE revealed an AUC of 0.63. There was no significant difference in age between patients who failed and those who passed (median = 8.8 years versus 7.0 years; p = 0.721). Based on our sample, SPT, egg white-specific IgE and age are not good predictors of passing a baked egg challenge. However, there was a trend for more predictability with SPT wheal size.

Is food allergy testing reliable in pediatric atopic dermatitis? A population-based study

We sought to assess the value and reliability of serologic testing for predicting clinical food allergy in a population-based cohort of infants with atopic dermatitis (AD). Infants 3-18 months of age, recruited from the general population, were followed quarterly for 3 years and carefully evaluated for evidence of immediate reactions to foods. Specific serum IgE levels for six foods were assayed at 3-5 years. Parents were interviewed at each visit regarding past/current immediate food-specific reactions involving skin, gut or respiratory systems. Data were entered into Excel for calculations of performance characteristics. Nine of the 40 patients (23%) who completed 3 years of follow-up had reactions to one or more foods. Reactions occurred in 5, 11 and 18% to milk, peanut and egg ingestion, respectively. In contrast, 30% of food-specific serum IgE tests were above normal. Predictive reliability of tests was generally low unless values were in the high range for peanut and milk. Conversely, egg allergy could be seen across a nearly full-spectrum of IgE values, making prediction highly unreliable. We conclude that physician and patient misinterpretation of the relevance and reliability of allergy testing may misdirect proper prevention and therapy of AD.

Specific IgE to common food allergens in children with atopic dermatitis

BACKGROUND

Atopic dermatitis is a major public health problem, often starting in early childhood and sometimes followed by other allergic diseases. Although hypersensitivity to foods is assumed to play an essential role in the development of atopic dermatitis in some patients, little is known about common food allergens in Iranian children with atopic dermatitis.

OBJECTIVES

This study was designed to identify probable food allergens in Iranian children with atopic dermatitis and find the relationship between food sensitization and the severity of atopic dermatitis.

METHODS

This study included 90 children aged 2-48 months with atopic dermatitis. Skin prick tests for cow's milk, hen's egg, almond, potato and soybean were done. Serum specific IgE to 20 food allergens was also screened.

RESULTS

Among children with atopic dermatitis, the frequency of food sensitization was 40% by skin prick test and 51% by food-specific IgE. Children with atopic dermatitis were most commonly sensitized to cow's milk (31%), hen's egg (17.7%), tree nuts (17.7%), wheat (12.2%), potato (11.1%), tomato (8.8%) and peanut (8.8%). In 42 children with moderate to severe eczema, sensitivity to food allergens was 78.5% by skin prick test and 88% by serum specific IgE evaluation.

CONCLUSION

Our results showed that cow's milk, hen's egg and tree nuts were the most common food allergens in Iranian children with atopic dermatitis. Sensitization to foods was much higher in patients with moderate to severe atopic dermatitis. Determining specific IgE in children with atopic dermatitis can be helpful in managing these patients.

Accidental allergic reactions in children allergic to hen's egg

BACKGROUND

Hen's egg is one of the main causes of food allergy in children. Accidental exposure is common in food-allergic patients. However, the few studies that analyze this problem focus mainly on peanut allergy. We sought to calculate the frequency of accidental exposure reactions in children allergic to hen's egg during a 12-month period, to analyze the clinical characteristics and circumstances surrounding the reactions, and to identify risk factors for the most severe reactions.

METHODS

Ninety-two egg-allergic children (55 boys; median age, 52 months) were included in the study. A systematic questionnaire about accidental exposure was administered. Reactions were classified as mild, moderate, and severe. Egg white-specific immunoglobulin (Ig) E antibody titers were determined.

RESULTS

Nineteen (21%) children had 24 reactions in the previous year (42% mild, 50% moderate, and 8% severe). Most reactions took place at home (50%) under routine circumstances (83%). Children with severe or moderate reactions had higher specific IgE levels to egg white (adjusted odds ratio for every 0.1-unit increase in the decimal logarithm, 1.15; 95% CI, 1.03-1.28; P = .008) and lower serum total IgE (adjusted odds ratio for every 1-unit increase in the decimal logarithm, 0.16; 95% CI, 0.05-0.54; P = .001) than those children with mild or no reactions.

CONCLUSIONS

Reactions to accidental exposure are frequent in children with egg allergy. The proportion of severe or moderate reactions was 58%. The risk factors for such reactions included high titers of specific IgE to egg white and low titers of serum total IgE.

Oral desensitisation with food is food-specific and protein-specific

The avoidance of food(s) is the main therapeutic approach to food allergy. Nevertheless, orally- or sublingually-administered food allergens have gained attention and a number of food-allergic children can tolerate gradually increasing amounts of cow&#x0027;s milk and hen&#x0027;s egg. Our purpose is to show that oral desensitisation with food is an allergen-specific therapeutic approach and for this, we describe 4 illustrative children with IgE-mediated food allergy. The first was allergic to cow&#x0027;s milk and hen&#x0027;s egg, the second to cow&#x0027;s milk, hen&#x0027;s egg and fish. Both underwent oral desensitisation to both cow&#x0027;s milk and hen&#x0027;s egg. The third child was allergic to cow&#x0027;s milk, hen&#x0027;s egg and fish and underwent oral desensitisation with cow&#x0027;s milk. The last child was allergic to raw but not to cooked/boiled hen&#x0027;s egg and underwent the oral desensitisation with hen&#x0027;s egg. The first 2 children reached the clinical tolerance to cow&#x0027;s milk after the cow&#x0027;s milk oral desensitisation, but reached the hen&#x0027;s egg tolerance only after the hen&#x0027;s egg oral desensitisation. Moreover, the second child did not tolerate fish after being desensitised to both cow&#x0027;s milk and hen&#x0027;s egg. The third child tolerated cow&#x0027;s milk, but not hen&#x0027;s egg and fish, at the end of the cow&#x0027;s milk oral desensitisation. The fourth child could tolerate the previously not tolerated raw hen&#x0027;s egg after the oral desensitisation with raw hen&#x0027;s egg. In conclusion, we indicate that oral desensitisation with food is allergen specific. The induction of the clinical tolerance to one food is not followed by the tolerance to the other food(s) that the patient is allergic to. To obtain a double or multiple food tolerance, separate desensitisation protocols, one for each food, have to be carried out. Oral desensitisation with food discriminates between raw and cooked proteins.

Anesthesia in the patient with multiple drug allergies: are all allergies the same?

PURPOSE OF REVIEW

During the preoperative evaluation, patients frequently indicate 'multiple drug allergies', most of which have not been validated. Potential allergic cross-reactivity between drugs and foods is frequently considered as a risk factor for perioperative hypersensitivity. The aim of this review is to facilitate the recognition of risk factors for perioperative anaphylaxis and help the management of patients with 'multiple drug allergies' during the perioperative period.

RECENT FINDINGS

Neuromuscular blocking agents (NMBAs) and antibiotics are the most common drugs triggering perioperative anaphylaxis. Quaternary ammonium ions have been suggested to be the allergenic determinant of NMBAs. Even though the 'pholcodine hypothesis' has been suggested to explain the occurrence of NMBA-induced allergy, this concept remains unclear. Although many practitioners believe that certain food allergies present an issue with the use of propofol, there is no role to contraindicate propofol in egg-allergic, soy-allergic or peanut-allergic patients. IgE-mediated hypersensitivity has been reported with seafood and iodinated drugs, IgE-mediated hypersensitivity has been reported with seafood and iodinated drugs, but there is no cross-reactivity between them. The allergenic determinants have been characterized for fish, shellfish and povidone iodine and remain unknown for contrast agents.

SUMMARY

There are many false assumptions regarding drug allergies. The main goal of this article is to review the potential cross-reactivity among specific families of drugs and foods in order to facilitate the anesthetic management of patients with 'multiple drug allergies'.

Is aboriginal food less allergenic? Comparing IgE-reactivity of eggs from modern and ancient chicken breeds in a cohort of allergic children

BACKGROUND

Hen's egg allergy ranks among the most frequent primary food allergies in children. We aimed to investigate sensitization profiles of egg allergic patients and compare in vitro IgE reactivities of eggs from ancient chicken breeds (Araucana and Maran) with those from conventional laying hen hybrids.

METHODOLOGY

Egg allergic children (n = 25) were subjected to skin prick test, double blind placebo controlled food challenge, and sensitization profiles to Gal d 1-5 were determined by allergen microarray. IgE binding and biological activity of eggs from different chicken breeds were investigated by immunoblot, ELISA, and mediator release assays.

PRINCIPAL FINDINGS

We found that Gal d 1 and Gal d 2 are generally major egg allergens, whereas Gal d 3-5 displayed high sensitization prevalence only in patients reacting to both, egg white and yolk. It seems that the onset of egg allergy is mediated by egg white allergens expanding to yolk sensitization in later stages of disease. Of note, egg white/yolk weight ratios were reduced in eggs from Auraucana and Maran chicken. As determined in IgE immunoblots and mass analysis, eggs from ancient chicken breeds did not differ in their protein composition. Similar IgE-binding was observed for all egg white preparations, while an elevated allergenicity was detected in egg yolk from Araucana chicken.

CONCLUSION/SIGNIFICANCE

Our results on allergenicity and biological activity do not confirm the common assumption that aboriginal food might be less allergenic. Comprehensive diagnosis of egg allergy should distinguish between reactivity to hen's egg white and yolk fractions to avoid unnecessary dietary restrictions to improve life quality of the allergic child and its family.

The role of hen's egg-specific IgE, IgG and IgG4 in the diagnostic procedure of hen's egg allergy

BACKGROUND

Hen's egg (HE) allergy is a common disease in childhood. HE-specific serum IgE has been correlated with the outcome of oral food challenge tests, and diagnostic decision points have been described as helpful but still not sufficient to reduce the requirement for oral food challenges. The aim of the study was to correlate HE-specific IgE, IgG and IgG4 levels with the outcome of double-blind, placebo-controlled food challenges (DBPCFC) in patients with suspected HE allergy to improve diagnostic procedures.

METHODS

HE-specific IgE, IgG, and IgG4 levels were compared between 150 children with suspected HE allergy based on sensitization and/or patient's history who underwent DBPCFC. Sixty-six patients were HE-allergic (HE-sensitized with a positive DBPCFC), 48 HE-sensitized but tolerant (negative DBPCFC), and 36 patients were nonsensitized and tolerant (negative DBPCFC). Prior to food challenge HE-specific serum IgE, IgG, and IgG4 were measured with the Phadia CAP-system.

RESULTS

HE-specific IgE was significantly higher in HE-allergic patients than in clinically tolerant ones. However, there was no difference in HE-specific IgG and IgG4 concentrations between the patient groups.

CONCLUSION

A proposed cut-off level of 12 kU/l IgE would identify children above this level correctly as HE-allergic. The level of HE-specific IgG or IgG4 in serum of children with suspected HE allergy does not add any additional information in the diagnostic procedure of HE allergy. For diagnostic purposes, specific IgG or IgG4 should not routinely be tested.

Results of the oral egg-challenge test performed on two different groups of children. One group with a history, suggestive of allergic reaction with egg intake and the other group sensitised to hen's egg without previous egg intake

INTRODUCTION

Egg allergy is an adverse immune-system reaction of an IgE-mediated type, which can happen in children after egg intake and several times after their first egg intake.

OBJECTIVES

Compare the results of the oral egg-challenge test in two groups of egg-sensitised children, with and without prior intake.

PATIENTS AND METHODS

Retrospective study of two egg-sensitised groups (72 subjects). Group 1: 22 children without prior egg-intake. Group 2: 50 children with a clinical history of adverse reactions after egg intake. Skin prick tests, egg-white specific IgE (sIgE) and yolk specific IgE, were performed on all children. The oral egg-challenge tests were performed after a period of egg-avoidance diet and when egg-white specific IgE levels were lower than 1.5K U/L.

RESULTS

31.8% of the children in Group 1 did not tolerate egg-intake whereas 38% of the children in Group 2 did not tolerate egg-intake. Egg-avoidance periods lasted 19.5 and 18 months, respectively. Egg-white specific IgE levels went down in both groups after an egg-avoidance diet. No statistically significant differences were found between the groups and the positivity of oral egg-challenge test.

CONCLUSIONS

No statistically significant differences were found in the behaviour of the two groups studied. Given the high risk of adverse reactions, it was recommended that any egg-introduction tests were to be performed in a hospital environment on the children who were sensitised to hen's egg (including children without prior egg intake).

Immunologic features of infants with milk or egg allergy enrolled in an observational study (Consortium of Food Allergy Research) of food allergy

BACKGROUND

Immune features of infants with food allergy have not been delineated.

OBJECTIVES

We sought to explore the basic mechanisms responsible for food allergy and identify biomarkers, such as skin prick test (SPT) responses, food-specific IgE levels, and mononuclear cell responses, in a cohort of infants with likely milk/egg allergy at increased risk of peanut allergy.

METHODS

Infants aged 3 to 15 months were enrolled with a positive SPT response to milk or egg and either a corresponding convincing clinical history of allergy to milk or egg or moderate-to-severe atopic dermatitis. Infants with known peanut allergy were excluded.

RESULTS

Overall, 512 infants (67% male) were studied, with 308 (60%) having a history of a clinical reaction. Skin test responses, detectable food-specific IgE, or both revealed sensitization as follows: milk, 78%; egg, 89%; and peanut, 69%. SPT responses and food-specific IgE levels were discrepant for peanut (15% for IgE > or = 0.35 kU(A)/L and negative SPT response vs 8% for positive SPT response and IgE <0.35 kU(A)/L, P = .001). Mononuclear cell allergen stimulation screening for CD25, cytokine-inducible SH2-containing protein (CISH), forkhead box protein 3 (FOXP3), GATA3, IL10, IL4, IFNG, and T-box transcription factor (TBET) expression by using casein, egg white, and peanut revealed that only allergen-induced IL4 expression was significantly increased in those with clinical allergy to milk (compared with nonallergic subjects) and in those sensitized to peanut, despite the absence of an increase in GATA3 mRNA expression.

CONCLUSIONS

Infants with likely milk/egg allergy are at considerably high risk of having increased peanut-specific IgE levels (potential allergy). Peanut-specific serum IgE levels were a more sensitive indicator of sensitization than SPT responses. Allergen-specific IL4 expression might be a marker of allergic risk. Absence of an increase in GATA3 mRNA expression suggests that allergen-specific IL-4 might not be of T-cell origin.

Lipocalin-type prostaglandin D synthase and egg white cystatin react with IgE antibodies from children with egg allergy

BACKGROUND

Ovalbumin, ovomucoid, ovotransferrin, lysozyme, and ovomucin are known to be major allergens found in egg white. Egg white protein is composed of over 30 proteins; many of which have neither been identified nor their allergenicities characterized. This study set out to analyze whether unknown proteins that bind to IgE antibodies in serum from patients with egg allergy exist in egg white.

METHODS

Diluted egg white proteins were separated by 2-dimensional (2-D) gel electrophoresis. Immunolabeling was performed on individual patient sera from 19 child patients with egg white allergy and 11 negative control subjects. Spots of egg white proteins that bound to the patients' IgE were identified by mass spectrometry-based proteomics.

RESULTS

Egg white proteins were separated into 63 spots. Twenty-five of the 63 reacted with egg allergy patients' sera, and 10 of the 25 reactive spots showed IgE-reactivity to controls as well. Specific bindings to the IgE from egg allergy patients were found in 15 spots; one of which was confirmed as ovotransferrin. Among the other 14 protein spots, egg white cystatin and lipocalin-type prostaglandin D synthase (L-PGDS) were newly identified proteins that reacted with IgE in patients with egg allergy.

CONCLUSIONS

We demonstrated that L-PGDS and cystatin reacted with serum IgE in patients with egg allergy. Our proteomics-based analysis in egg white gives a comprehensive map of proteins bound with IgE and should assist in enabling more accurate diagnoses and recommendations of desensitizing treatments for individual patients.

Vinegar decreases allergenic response in lentil and egg food allergy

BACKGROUND

Food allergy results from an atypical response of the mucosal immune system to orally consumed allergens. Antacid medication inhibits the digestion of dietary proteins and causes food allergy. A decrease of the gastric pH might enhance the function of digestion and reduce the risk of food allergy.

OBJECTIVE

To test a possible decrease in the allergenicity of powerful food allergens (egg, chicken, lentils) with the addition of vinegar during the cooking process.

METHODS

We included seven patients who suffered from anaphylaxis due to egg, chicken and lentils. We added vinegar to egg, chicken and lentil processed extracts used for skin prick tests (SPT) and compared the wheal areas obtained with the same extracts sources and the same way but without vinegar addition. Immunodetection was performed with the different processed extracts and patients' sera. Only one patient consented food challenge with vinegar-marinated-chicken.

RESULTS

Wheal areas were significantly minor with the food extract with vinegar. Immunodetection showed a decrease of the response with vinegar processed extracts.

CONCLUSIONS

Vinegar addition during the cooking process may decrease lentil and chicken allergenicity.

Rush specific oral tolerance induction in school-age children with severe egg allergy: one year follow up

BACKGROUND

At present, the only treatment for food allergy is to avoid the allergy-causing food. Some trials of specific oral tolerance induction (SOTI) have been carried out, but the rate of tolerance induction was low despite long treatment periods, at least 3 months to several years. A new type of treatment is long desired. The objectives of this study are to perform our rush SOTI for school-age patients with severe egg allergy, and to evaluate the safety and efficacy of this method for one year.

METHODS

Six school-age children (7-12 years of age) with severe IgE-mediated egg allergy confirmed by double-blind, placebo-controlled food challenge (DBPCFC) underwent rush SOTI, in which patients ingested increasing doses of egg several times every day. After rush SOTI, patients ingested the maintenance dose of egg at least twice a week.

RESULTS

In DBPCFC, the median threshold dose of egg white inducing allergic reactions was 0.152 g (0.012-0.360 g). All subjects acquired tolerance to more than one whole egg (60 g). It took only 12 days (9-18 days). None experienced any serious reaction. We observed a decrease in IL-10 and an increase in TGF-beta1 at 6 months and a decrease in egg-specific IgE and an increase in egg white-specific IgG4 at 12 months after rush SOTI in blood. All subjects have been able to ingest more than one whole egg ever since.

CONCLUSIONS

Our rush SOTI is a safe and effective treatment for severe food allergy since only a few weeks are needed to acquire tolerance. It would replace allergen avoidance as the treatment for food allergy.

A method for the analysis of milk and egg allergens for the atopy patch test

The patch test with food antigens (atopy patch test, APT) has been reported as a more specific method than prick or RAST for the early detection of cow's milk and/or egg sensitizations in children. Standardization of APT extracts is a major issue on the road towards full clinical exploitation of this assay. Here, we used sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) to characterize sensitivity and specificity of commercial preparations of APT for milk and egg allergies, which are expected to improve the reliability of this test, when compared with fresh food allergen sources. We found that: (i) SDS-PAGE is an appropriate technique for quality control of APT and (ii) commercial milk and egg APT are equivalent to fresh food preparations in terms of allergen content. Clinical trials aimed at characterizing sensitivity and specificity of APT in the diagnosis of food allergy in children will benefit from this technique.

Food allergens and respiratory symptoms

Food allergy may be clinically expressed by a variety of respiratory symptoms, which can be provoked either by IgE- or cellular mediated reactions. Among the diagnostic procedures, newly introduced atopy patch test seems to be important for diagnosis of cellular, delayed immune reactions. We studied the prevalence of positive atopy patch tests with food and inhalant allergens and the correlation between the positivity of atopy patch tests and questionnaire derived atopic and nonatopic espiratory symptoms and diseases in an unselected children population. We found a correlation between the positive patch test result with wheat and cough after physical effort, allergic rhino-conjunctivitis, and bronchitis recidivans. The subjects with positive skin reaction to egg suffered from allergic rhino-conjunctivitis and bronchial asthma. Food and inhalant allergens play an important role in the induction and exacerbation of some respiratory allergic diseases. The positive correlation of positive results of skin tests and history of some respiratory diseases and symptoms also on the population level confirm the importance of these tests in the diagnostic work-up of these allergic diseases.