Paradigm shift in the management of milk and egg allergy: baked milk and egg diet

The future of cow's milk allergy - milk ladders in IgE-mediated food allergy

Cow's milk allergy (CMA) is one of the most common and complex presentations of allergy in early childhood. CMA can present as IgE and non-IgE mediated forms of food allergy. Non-IgE mediated CMA includes food protein-induced enterocolitis syndrome (FPIES), eosinophilic gastrointestinal disorders (EGIDs), and food protein-induced proctocolitis (FPIAP). There are recent guidelines addressing CMA diagnosis, management, and treatment. Each of these guidelines have their own strengths and limitations. To best manage CMA, individualized avoidance advice should be given. Cow's milk (CM) can be replaced in the diet by using hypoallergenic formulas or plant-based milk, depending on factors such as the child's age and their current food intake. Oral and epicutaneous immunotherapy is used to increase tolerance in children with CMA but is not without risk, and the long-term outcome of sustained unresponsiveness is still unclear. The allergenicity of CM proteins are affected differently by different forms of heating, leading to the use of baked milk or milk ladders in the management of CMA, most likely the most promising option for future management and treatment of CMA. Future management of children with CMA will also include discussion around the immunomodulatory potential of the child's dietary intake.

Passive tolerance and productive uncertainties in food allergy immunotherapy biomedical practices

There has been little sociological research on food allergy in North America, despite the fact that it impacts a significant population in the US and Canada. Immunotherapy for food allergy is now a prominent area of investigation and experts argue it is one dimension of a 'paradigm shift' that encourages exposure to food allergens in contrast to avoidance of them. This article reports on an ethnographic investigation of immunotherapy for food allergy research and practice between the years 2015 and 2020. I report on analyses of N = 31 in-depth interviews with spokespersons with different types of engagement in immunotherapy and over 100 h of ethnographic observations at clinical and scientific conferences. My research revealed the entangled ontologies of food and drug in immunotherapy and related uncertainties in the diagnoses of food allergy, which catalysed further uncertainty about who is receiving and who should receive immunotherapy (IT). Relatedly, there are uncertainties about the goals and/or outcomes of IT. I elaborate on previous sociological work about how uncertainty is valued in medicine and science. I argue shared uncertainties and mutual scepticism in IT co-exist, representing a passive (productive) tolerance and reticently accepted form of tension in the domain, which have resulted in calls for intra-professional and inter-professional collaborations and the involvement of other stakeholders in knowledge making regarding food allergy immunotherapy.

The Impact of Baked Egg and Baked Milk Diets on IgE- and Non-IgE-Mediated Allergy

Baked milk (BM) and baked egg (BE) diets are increasingly used in the management of milk and egg allergy, rather than avoidance. Children with tolerance versus reactivity to BM and BE may have smaller skin prick test and lower specific IgE, and BM-tolerant children have less basophil reactivity and more peripheral T regulatory cells. However, most milk- and egg-allergic children tolerate BM and BE and an individual's reactivity is unpredictable. Non-reactivity is due to conformational changes in the allergens. Significant differences in the published advice about methods of introduction exist from graded introduction at home to a medically supervised full dose. These approaches carry different risks and may have different immunological effects. Reactivity to BM is a predictor of a severe milk allergy. Therefore, medical supervision for BM and BE introduction is prudent. The baked diet allows dietary liberation. Most, but not all, BM- and BE-tolerant children continue eating the baked foods. The prognosis of children who can eat BM and BE is favorable with likely resolution of their allergy over the next few years. Murine models of BE diets demonstrate that heated egg can impart clinical protection against anaphylaxis and cause immune changes. Most observational human studies of BM and BE diets demonstrate clinical resolution of allergy and favorable immune changes versus regular care controls. However, the one randomized controlled trial for the BE diet in BE-tolerant children did not support an immune-modifying effect of the BE diet. Another study of BE immunotherapy is expected to be completed in 2018. There is currently no evidence for prevention of allergy with the baked diets. There may be a future role for BM and BE in liberating the diets of individuals with non-IgE-mediated allergy given recent studies that a subset of these patients can consume BM without a clinical reaction.

Randomised controlled trial of a baked egg intervention in young children allergic to raw egg but not baked egg

BACKGROUND

Consumption of baked egg by raw egg allergic children is associated with immune changes suggesting development of tolerance. However, causation has not been tested using a double blind randomized controlled trial (RCT). We aimed to compare clinical and immunological outcomes after baked egg (BE) consumption in young BE tolerant egg allergic children.

METHODS

In a double blind RCT, BE tolerant egg allergic children consumed 10 g BE (1.3 g protein) 2 to 3 times per week for 6 months (n = 21 intervention group) or similar egg free baked goods (n = 22 control group) while maintaining an otherwise egg free diet. The final assessment was a raw egg oral food challenge (OFC) 1 month after ceasing the intervention product. Egg specific IgE and IgG4 were assessed at baseline and 7 months.

RESULTS

After the intervention there was no difference in raw egg tolerance between groups, (23.5% (4/17) intervention group and 33.3% (6/18) control group). This was independent of age and amount of BE consumed (aOR 0.50 CI 0.11-2.40 p = 0.39). Both groups demonstrated decreased egg specific serum IgE titres and decreased whole egg specific IgE/IgG4 ratios.

DISCUSSION

We conducted this trial because inclusion of baked egg protein in the diet of egg allergic children appears to move children towards a more tolerant immune profile. Strengths of our study include design of the blinded intervention, the consistent dosing protocol and the regular monitoring of symptoms and intake. However, the study was limited by small sample size resulting in insufficient power to show statistically significant results.

CONCLUSION

Our study suggests that short term, regular consumption of BE by BE tolerant 1 to 5 year old children with IgE mediated raw egg allergy may not induce, accelerate or slow development of tolerance to raw egg in this selected population. Trials with larger sample sizes are required to further test this hypothesis.

TRIAL REGISTRATION

The trial was registered on 7th February 2012 with the Australian New Zealand Clinical Trials Registry (ACTRN 12612000173897).

Baked milk tolerant patient: Is there any special feature?

BACKGROUND

Determining whether patients with cow's milk allergy (CMA) can tolerate foods produced with baked milk could provide a better quality of life, a better prognosis, and an option for desensitization.

OBJECTIVES

The aim of this study was to identify which patients over four years of age with persistent CMA could tolerate baked milk, to compare the clinical and laboratory characteristics of reactive and non-reactive groups and to describe their clinical evolution.

MATERIALS AND METHODS

A cross-sectional study was conducted (January/13 to November/14) that included all the patients followed at a food allergy center who met the inclusion criteria. The patients underwent an oral food challenge (OFC) with a muffin (2.8g of cow's milk protein). To exclude cow's milk (CM) tolerance, the patients were subsequently challenged with unheated CM.

RESULTS

Thirty patients met all the inclusion criteria. Fourteen patients (46.7%) were considered non-reactive to baked milk and reactive to unheated CM. When the groups that were reactive and non-reactive to baked milk were compared, no statistically significant differences in clinical features were found. The prick test for α-lactalbumin (p=0.01) and casein (p=0.004) and the serum specific IgE for casein (p=0.05) presented statistical differences. After one year, none of the patients who were reactive to baked milk were ingesting CM, while 28% of the tolerant patients were consuming fresh CM (p=0.037).

CONCLUSIONS

Baked milk can be tolerated by patients with CMA, especially those with lower levels of casein and α-lactalbumin. This option can improve quality of life and accelerate tolerance.

Enzyme-Linked Immunosorbent Assay (ELISA)

Food allergy is a public health concern especially after recognizing its constantly increased prevalence and severity. Despite careful reading of food ingredient statements, food allergic individuals may experience reactions caused by "hidden", "masked", or "contaminated" proteins that are known major allergens. Many techniques have been developed to detect even small traces of food allergens, for clinical or laboratory purposes. Enzyme-linked immunosorbent assay (ELISA) is one of the best validated and most routinely used immunoassay in allergy research, in allergy diagnosis in allergy-related quality control in various industries. Although as a technique it has been implemented for the last 45 years, the evolution in biochemistry allowed the development of ultrasensitive ELISA variations that are capable of measuring quantities in the scale of picograms, rendering ELISA attractive, robust, and very famous.

Oral immunotherapy for food allergy: mechanisms and role in management

With the emergence of food allergy as an important public health problem, it has become clear that there is an unmet need in regard to treatment. In particular, IgE-mediated food allergy that is associated with risk of fatal anaphylaxis has been the subject of multiple studies in the past decade. The growing body of evidence derived from multiple centres and various study designs indicates that for IgE-mediated food allergy, immunomodulation through food immunotherapy is possible; however, the extent of protection afforded by such treatment is highly variable. At this time, the capacity for food immunotherapy to restore permanent tolerance to food has not been demonstrated conclusively. This review will discuss these topics as they apply to the most important studies of food oral immunotherapy.

Efficacy of baked milk oral immunotherapy in baked milk-reactive allergic patients

BACKGROUND

Patients with IgE-mediated cow's milk allergy who are nonreactive to baked milk (BM) can be desensitized with BM to promote tolerance to unheated milk (UM).

OBJECTIVE

We sought to test whether patients who are BM reactive can progress in BM oral immunotherapy (OIT) and become desensitized to UM as well.

METHODS

Fifteen patients (>4 years) who previously failed to complete our milk OIT program were enrolled into the BM OIT protocol. A dose of BM (180 °C for 30 minutes) which was less than the eliciting dose was increased 50% monthly while under medical supervision until the primary outcome dose of 1.3 g/d BM protein was achieved. Basophil reactivity and milk protein-specific IgE binding were analyzed at the first round of BM OIT therapy (T0) and at 12 months of BM treatment.

RESULTS

In terms of the primary outcome, only 3 (21%) of 14 patients tolerated the 1.3 g/d BM dose. Although some patients initially progressed in BM OIT, 8 of 11 failed because of IgE-mediated reactions. Three did not complete the program because of non-IgE-mediated factors. An increase in challenge threshold to UM was noted in patients continuing until 12 months (P = .003), including those among whom reactions precluded continuation in the program. Patients (n = 3) who successfully reached maintenance had decreased milk-specific IgE reactivity. Furthermore, the mean difference at T0 between induced HM and UM percentages of CD203c expression was significantly lower in patients who successfully completed BM OIT than in those who did not (-11% vs 4.4%, P = .0002), which is consistent with their decreased clinical reactivity to BM.

CONCLUSIONS

Although use of hypoallergenic BM in OIT is a promising therapy, care must be taken before its administration in BM-reactive patients because of the risk for anaphylaxis and only limited increase in challenge threshold attained.

Fifty years of allergy: 1965-2015

The last 50 years in allergy could almost be considered the first 50 years. Over this time period, we have witnessed the emergence of allergy as a subspecialty, have seen and continue to observe a tremendous change in prevalence of allergic disease and have gained insight into the mechanisms that underlie allergic predisposition and disease manifestation. We have improved the care of children with many forms of allergic disease and now sit poised to be able to alter the natural history of allergic disease with the use of specific immunotherapy. There is much left to do in the next 50 years including understanding what underlies both the predisposition to atopic disease and its natural resolution and identifying the environmental cofactors involved in the 'allergic epidemic' and therefore targets for effective primary prevention.

Effect of heat treatment on milk and egg proteins allergenicity

BACKGROUND

Heating destroys many conformational epitopes and reduces allergenicity of some foods. IgE-epitope binding has been shown to be different among patients who outgrew their cow's milk or hen's egg allergy and those who did not. A significant proportion of milk- or egg-allergic children are tolerant to these foods in their baked forms. We sought to explore the effects of heating on milk and egg proteins and to evaluate for differences in immunolabeling among children with regard to reactivity to heated milk or egg.

METHODS

Sera from participants in clinical dietary intervention trials were utilized. Milk and egg samples were variably heated and prepared (at times within a wheat matrix). Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), protein transfer, and Western blot were completed.

RESULTS

Sera from 20 milk-allergic and 24 egg-allergic children were utilized. Gel electrophoresis showed strongly staining casein bands that persisted for up to 60 min of heating. In contrast, β-lactoglobulin and α-lactalbumin bands became progressively weaker with increasing heating times, with no detectable β-lactoglobulin after 15-20 min of heating. The ovalbumin band became progressively weaker, whereas ovomucoid remained stable after 25 min of heating. Immunolabeling revealed that all heated milk-reactive children possessed IgE antibodies that bound the casein fraction regardless of heating time. Presence of wheat during heating resulted in decreased IgE antibody binding to milk and egg white proteins.

CONCLUSION

Heating has a different effect on whey and caseins in cow's milk and ovalbumin and ovomucoid in hen's egg white. The effect of heat on protein allergenicity is affected by the temperature and duration, along with the presence of wheat.

The natural history and clinical predictors of egg allergy in the first 2 years of life: a prospective, population-based cohort study

BACKGROUND

There is a paucity of data examining the natural history of and risk factors for egg allergy persistence, the most common IgE-mediated food allergy in infants.

OBJECTIVE

We aimed to assess the natural history of egg allergy and identify clinical predictors for persistent egg allergy in a population-based cohort.

METHODS

The HealthNuts study is a prospective, population-based cohort study of 5276 infants who underwent skin prick tests to 4 allergens, including egg. Infants with a detectable wheal were offered hospital-based oral food challenges (OFCs) to egg, irrespective of skin prick test wheal sizes. Infants with challenge-confirmed raw egg allergy were offered baked egg OFCs at age 1 year and follow-up at age 2 years, with repeat OFCs to raw egg.

RESULTS

One hundred forty infants with challenge-confirmed egg allergy at age 1 year participated in the follow-up. Egg allergy resolved in 66 (47%) infants (95% CI, 37% to 56%) by 2 years of age; however, resolution was lower in children with baked egg allergy at age 1 year compared with baked egg tolerance (13% and 56%, respectively; adjusted odds ratio, 5.27; 95% CI, 1.36-20.50; P = .02). In the subgroup of infants who were tolerant to baked egg at age 1 year, frequent ingestion of baked egg (≥5 times per month) compared with infrequent ingestion (0-4 times per month) increased the likelihood of tolerance (adjusted odds ratio, 3.52; 95% CI, 1.38-8.98; P = .009). Mutation in the filaggrin gene was not associated with the resolution of either egg allergy or egg sensitization at age 2 years.

CONCLUSION

Phenotyping of egg allergy (baked egg tolerant vs allergic) should be considered in the management of this allergy because it has prognostic implications and eases dietary restrictions. Randomized controlled trials for egg oral immunotherapy should consider stratifying at baseline by the baked egg subphenotype to account for the differential rate of tolerance development.

Food allergen selective thermal processing regimens may change oral tolerance in infancy

Food allergy can be considered a failure in the induction of oral tolerance. Recently, great interest has been focused on understanding the mechanisms and the contributing factors of oral tolerance development, hoping for new definitive interventions in the prevention and treatment of food allergy. Given that food processing may modify the properties and the nature of dietary proteins, several food processing methods could affect the allergenicity of these proteins and consequently may favour oral tolerance induction to food allergic children. Indeed, effective thermal food processing regimens of altering food proteins to reduce allergenicity have been recently reported in the literature. This article is mainly focused on the effect of selective thermal processing regimens on the main infant allergenic foods, with a potential clinical relevance on their allergenicity and therefore on oral tolerance induction. In the light of recent findings, the acquisition of tolerance in younger age and consequently the ability of young children to "outgrow" food allergy could be achieved through the application of selective thermal processing regimens on certain allergenic foods. Therefore, the ability of processed foods to circumvent clinical disease and at the same time to have an impact on the immune system and facilitate tolerance induction could be invaluable as a component of a successful therapeutic strategy. The opening in the new avenues of research in the use of processed foods in clinical practice for the amelioration of the impact on the quality of life of patients and possibly in food allergy prevention is warranted.

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.

Tolerability of a fully maturated cheese in cow's milk allergic children: biochemical, immunochemical, and clinical aspects

BACKGROUND

From patients' reports and our preliminary observations, a fully maturated cheese (Parmigiano-Reggiano; PR) seems to be well tolerated by a subset of cow's milk (CM) allergic patients.

OBJECTIVE AND METHODS

To biochemically and immunologically characterize PR samples at different maturation stage and to verify PR tolerability in CM allergic children. Seventy patients, with suspected CM allergy, were enrolled. IgE to CM, α-lactalbumin (ALA), β-lactoglobulin (BLG) and caseins (CAS) were tested using ImmunoCAP, ISAC103 and skin prick test. Patients underwent a double-blind, placebo-controlled food challenge with CM, and an open food challenge with 36 months-maturated PR. Extracts obtained from PR samples were biochemically analyzed in order to determine protein and peptide contents. Pepsin and trypsin-chymotrypsin-pepsin simulated digestions were applied to PR extracts. Each PR extract was investigated by IgE Single Point Highest Inhibition Achievable assay (SPHIAa). The efficiency analysis was carried out using CM and PR oral challenges as gold standards.

RESULTS

The IgE binding to milk allergens was 100% inhibited by almost all PR preparations; the only difference was for CAS, mainly α(S1)-CAS. Sixteen patients sensitized to CM tolerated both CM and PR; 29 patients tolerated PR only; 21 patients, reacted to both CM and PR, whereas 4 patients reactive to CM refused to ingest PR. ROC analysis showed that the absence of IgE to BLG measured by ISAC could be a good marker of PR tolerance. The SPHIAa using digested PR preparations showed a marked effect on IgE binding to CAS and almost none on ALA and BLG.

CONCLUSIONS

58% of patients clinically reactive to CM tolerated fully maturated PR. The preliminary digestion of CAS induced by PR maturation process, facilitating a further loss of allergenic reactivity during gut digestion, might explain the tolerance. This hypothesis seems to work when no IgE sensitization to ISAC BLG is detected.

Skin prick testing with extensively heated milk or egg products helps predict the outcome of an oral food challenge: a retrospective analysis

Background

Cow’s milk and hen’s egg are the most frequently encountered food allergens in the pediatric population. Skin prick testing (SPT) with commercial extracts followed by an oral food challenge (OFC) are routinely performed in the diagnostic investigation of these children. Recent evidence suggests that milk-allergic and/or egg-allergic individuals can often tolerate extensively heated (EH) forms of these foods. This study evaluated the predictive value of a negative SPT with EH milk or egg in determining whether a child would tolerate an OFC to the EH food product.

Methods

Charts from a single allergy clinic were reviewed for any patient with a negative SPT to EH milk or egg, prepared in the form of a muffin. Data collected included age, sex, symptoms of food allergy, co-morbidities and the success of the OFC to the muffin.

Results

Fifty-eight patients had negative SPTs to the EH milk or egg in a muffin and underwent OFC to the appropriate EH food in the outpatient clinic. Fifty-five of these patients tolerated the OFC. The negative predictive value for the SPT with the EH food product was 94.8%.

Conclusions

SPT with EH milk or egg products was predictive of a successful OFC to the same food. Larger prospective studies are required to substantiate these findings.