Tolerance to extensively heated milk in children with cow's milk allergy

Recombinant barley-produced antibody for detection and immunoprecipitation of the major bovine milk allergen, β-lactoglobulin

Recombinant allergens and antibodies are needed for diagnostic, therapeutic, food processing and quality verification purposes. The aim of this work was to develop a barley-based production system for β-lactoglobulin (BLG) specific immunoglobulin E antibody (D1 scFv). The expression level in the best barley cell clone was 0.8-1.2 mg/kg fresh weight, and was constant over an expression period of 21 days. In the case of barley grains, the highest stable productivity (followed up to T2 grains) was obtained when the D1 scFv cDNA was expressed under a seed-specific Glutelin promoter rather than under the constitutive Ubiquitin promoter. Translational fusion of ER retention signal significantly improved the accumulation of recombinant antibody. Furthermore, lines without ER retention signal lost D1 scFv accumulation in T2 grains. Pilot scale purification was performed for a T2 grain pool (51 g) containing 55.0 mg D1 scFv/kg grains. The crude extract was purified by a two-step purification protocol including IMAC and size exclusion chromatography. The purification resulted in a yield of 0.47 mg of D1 scFv (31 kD) with high purity. Enzyme-linked immunosorbent assay revealed that 29 % of the purified protein was fully functional. In immunoprecipitation assay the purified D1 scFv recognized the native 18 kD BLG in the milk sample. No binding was observed with the heat-treated milk sample, as expected. The developed barley-based expression system clearly demonstrated its potential for application in the processing of dairy milk products as well as in detecting allergens from foods possibly contaminated by bovine milk.

Food Allergy

Food allergy has established itself as a matter of significant public health importance and relevance. It has had substantial impacts across the world and continues to represent the most common cause of anaphylaxis seen in emergent settings. However, its increasing incidence has yielded a silver lining of increased interest and investment, which has powered major research in the field. Much has been learned about food allergy as a result. Recent work has elicited increased understanding about food allergy prevalence, mechanisms, and risk factors. In turn, this has allowed for application of this understanding to potential treatments. Current practice of food allergy treatment through restricted exposure may ultimately be replaced with novel therapies including, perhaps ironically, introduction of the allergenic foods in question. This review presents broad highlights of the rapidly increasing understanding into food allergy mechanisms and experimental therapies.

Usefulness of nBos d 4, 5 and nBos d 8 Specific IgE Antibodies in Cow's Milk Allergic Children

PURPOSE

The aim of study was to assess the value of recombinants in predicting the degree of symptoms in children with and without anaphylaxis to cow's milk.

METHODS

The study included 79 children (70±40 months) referred to the Allergological Unit of the Pediatric Department between the years 2008-2012. Group A was composed of 17 children (78±49.6 months) with anaphylaxis after ingestion of milk. Group B was composed of 62 children (73.1±38.6 months) without a history of anaphylaxis, but with less severe symptoms (gastrointestinal and/or skin symptoms). All patients from Group B had a positive open challenge with cow's milk. All patients underwent an allergic evaluation and blood samples were collected to test for IgE to recombinans of milk (nBos d 4, 5, 8).

RESULTS

A significant difference in nBos d 8 emerged with higher levels in Group A (median [IQR]=2.80 [0.91-16.1]) than B (0.65 [0.24-1.67]; P=0.006), whereas there were no statistically significant differences for nBos d 4 and 5. The recombinants' sum was higher in Group A than B: 8.39 [2.72-41.39] vs 3.04 [1.85-7.31] kUA/L; P=0.044. The recombinant nBos d 8 was superior to the other recombinants in identifying children at risk for anaphylaxis, with an area under the curve of 0.718 (95% CI, 0.57-0.86, P=0.006). Considering a cutoff of 1.8 kUA/L, nBos d 8 had the most favorable sensitivity and specificity ratio (sensitivity=0.65, specificity=0.77) with an odd ratio of 6.02 (95% C.I: 1.89-19.23).

CONCLUSIONS

This study suggested 2 phenotypes of allergic children, "high-anaphylaxis-risk" and "milder-risk". These types can be differentiated through measuring the level of IgE to nBos d 8.

How to reintroduce cow's milk?

In a child that is allergic to milk, the natural next step, following the elimination diet, is the reintroduction of cow's milk. Several questions may arise. When feasible, this reintroduction has many benefits for the child and his family. However, the disease needs to be well defined by physicians and explained to parents. They need to understand that there are different types of allergy to cow's milk, specifically IgE- and non-IgE-mediated, and each of these may exhibit both a variable duration and frequently an incomplete recovery. Deciding where to first reintroduce cow's milk to a child who has previously followed a milk-free diet, whether it be at home or in a hospital, also frequently presents an issue. Following this first reintroduction, the progressive increase of milk into the diet needs to be managed properly, as not all children will go back to a normal dairy products intake. Recent studies show that most children with milk allergy tolerate products containing baked milk and that their consumption might speed up recovery. Hence, the purpose of the milk challenge in a child on a milk-free diet is becoming, even in a child still reactive to milk, the first step of gradual and individually adapted reintroduction of milk or dairy products. When reintroduction of cow's milk does not work, immunotherapy becomes an option, and this is carried out in specialized centers.

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.

Food allergy diagnosis and therapy: where are we now?

Food allergy is a growing worldwide epidemic that adversely effects up to 10% of the population. Causes and risk factors remain unclear and diagnostic methods are imprecise. There is currently no accepted treatment for food allergy. Therefore, there is an imminent need for greater understanding of food allergies, revised diagnostics and development of safe, effective therapies. Oral immunotherapy provides a particularly promising avenue, but is still highly experimental and not ready for clinical use.

Intestinal permeability in children with food allergy on specific elimination diets

BACKGROUND

Children with food allergy have been shown to have increased small intestinal permeability (IP) following ingestion of the offending food as well as during elimination diets. We investigated IP in asymptomatic food allergic children during an elimination diet to identify clinical characteristics associated with altered IP.

METHODS

Urinary recovery ratios of lactulose and mannitol (L/M) were determined 5 h following ingestion of 7.5 g of lactulose and 2 g of mannitol in 131 cow's milk and egg allergic children. An L/M ratio of ≥0.025 was considered abnormal based upon previously established laboratory internal references. A chart review was conducted to assess the clinical characteristics of these patients.

RESULTS

A total of 50 (38%) of the 131 children (median 6.7, range 4.8-8.9 yr; 66.2% male) with food allergy had elevated IP while asymptomatic on strict elimination diets. Age and height negatively correlated with IP. However, in the regression model analysis, abnormal IP was associated with shorter stature independently of age. Otherwise, food allergic patients with increased IP were comparable in gender, nutritional status, age of onset of food allergy, history of reactions, atopic diseases, and family history of food allergies to those with normal IP.

CONCLUSIONS

Elevated IP was found in about one-third of asymptomatic food allergic children on elimination diets and was associated with shorter stature. Our results suggest that increased IP may be an intrinsic trait in a subset of food allergic children. However, large, prospective studies are necessary to determine the role of impaired intestinal barrier in food allergy.

Oral immunotherapy and tolerance induction in childhood

Prevalence rates of food allergy have increased rapidly in recent decades. Of concern, rates of increase are greatest among children under 5 yrs of age and for those food allergies that persist into adulthood such as peanut or tree nut allergy and shellfish allergy. Given these trends, the overall prevalence of food allergy will compound over time as the number of children affected by food allergy soars and a greater proportion of food-allergic children are left with persistent disease into adulthood. It is therefore vital to identify novel curative treatment approaches for food allergy. Acquisition of oral tolerance to the diverse array of ingested food antigens and intestinal microbiota is an active immunologic process that is successfully established in the majority of individuals. In subjects who develop food allergy, there is a failure or loss of oral tolerance acquisition to a limited number of food allergens. Oral immunotherapy (OIT) offers a promising approach to induce specific oral tolerance to selected food allergens and represents a potential strategy for long-term curative treatment of food allergy. This review will summarize the current understanding of oral tolerance and clinical trials of OIT for the treatment of food allergy.

Oral and sublingual immunotherapy for food allergy: current progress and future directions

Food allergies are increasing in prevalence and present an emerging epidemic for westernized countries. Strict dietary avoidance is the only approved management for food allergy, but accidental exposures regularly occur, leading to significant patient anxiety and decreased quality of life. Over the past decade, oral and sublingual immunotherapies have emerged as potential treatments for food allergy. While several small clinical trials have demonstrated that immunotherapy can desensitize food-allergic individuals, strategies for further enhancing safety and definitively establishing long-term efficacy are needed. This review presents an overview of recent oral and sublingual immunotherapy trials, and provides a glimpse into what the next generation of food immunotherapy may entail.

Cow's milk allergy: from allergens to new forms of diagnosis, therapy and prevention

The first adverse reactions to cow's milk were already described 2,000 years ago. However, it was only 50 years ago that several groups started with the analysis of cow's milk allergens. Meanwhile the spectrum of allergy eliciting proteins within cow's milk is identified and several cow's milk allergens have been characterized regarding their biochemical properties, fold and IgE binding epitopes. The diagnosis of cow's milk allergy is diverse ranging from fast and cheap in vitro assays to elaborate in vivo assays. Considerable effort was spent to improve the diagnosis from an extract-based into a component resolved concept. There is still no suitable therapy available against cow's milk allergy except avoidance. Therefore research needs to focus on the development of suitable and safe immunotherapies that do not elicit severe side effect.

Diagnosis and management of non-IgE-mediated cow's milk allergy in infancy - a UK primary care practical guide

The UK NICE guideline on the Diagnosis and Assessment of Food Allergy in Children and Young People was published in 2011, highlighting the important role of primary care physicians, dietitians, nurses and other community based health care professionals in the diagnosis and assessment of IgE and non-IgE-mediated food allergies in children. The guideline suggests that those with suspected IgE-mediated disease and those suspected to suffer from severe non-IgE-mediated disease are referred on to secondary or tertiary level care. What is evident from this guideline is that the responsibility for the diagnostic food challenge, ongoing management and determining of tolerance to cow’s milk in children with less severe non-IgE-mediated food allergies is ultimately that of the primary care/community based health care staff, but this discussion fell outside of the current NICE guideline. Some clinical members of the guideline development group (CV, JW, ATF, TB) therefore felt that there was a particular need to extend this into a more practical guideline for cow’s milk allergy. This subset of the guideline development group with the additional expertise of a paediatric gastroenterologist (NS) therefore aimed to produce a UK Primary Care Guideline for the initial clinical recognition of all forms of cow’s milk allergy and the ongoing management of those with non-severe non-IgE-mediated cow’s milk allergy in the form of algorithms. These algorithms will be discussed in this review paper, drawing on guidance primarily from the UK NICE guideline, but also from the DRACMA guidelines, ESPGHAN guidelines, Australian guidelines and the US NIAID guidelines.

Effect of thermal processing of cow and buffalo milk on the allergenic response to caseins and whey proteins in mice

BACKGROUND

Heat treatment is the most common method for reducing pathogen load, but it remains controversial in reducing the incidence of hyperimmune reactions. The aim of this study was to compare the allergenicity of caseins (CSN) and whey proteins (WP) of thermally processed cow and buffalo milk in a mouse model. Swiss albino mice were sensitised by intraperitoneal injections (administered in three doses at weekly intervals) of CSN or WP from cow or buffalo milk for the evaluation of humoral response and splenocyte stimulation index.

RESULTS

After 3 weeks of intraperitoneal stimulation of mice with milk proteins, the sterilised milk protein group displayed significantly lowered (P ≤ 0.05) serum IgG and IgE levels, while considerably increased cow milk protein-specific responses (IgE) were shown by proteins of pasteurised milk compared with those of raw milk. The stimulation index of splenocytes induced by CSN or WP of boiled and sterilised milk was also lower (P ≤ 0.05) than that of raw milk of both cow and buffalo.

CONCLUSION

The experiment showed that boiling and sterilisation of cow and buffalo milk clearly affect the allergenicity by decreasing the humoral and cell-mediated responses in mice. All results indicated that CSN and WP of sterilised milk are less allergenic than those of raw milk in mice.

Oral immunotherapy for food allergy: clinical and preclinical studies

Food allergies affect approximately 5% of the U.S. population and have increased in the last decade. In recent years, oral immunotherapy (OIT) has been tested in clinical trials for peanut, milk, and egg allergies in young children. OIT appears to be fairly well tolerated by most subjects and leads to desensitization with a greatly increased threshold of allergen required to induce reactions. Further approaches being investigated in preclinical studies in mouse models indicate the potential for using adjuvants, such as TLR9 agonists in combination with OIT; peptide OIT; and non-allergen specific applications such as herbal formulations. Further questions about OIT remain, including the optimal dosing and length of treatment; whether tolerance can be developed; and the exact cellular mechanisms resulting in protection following OIT. With many clinical trials underway across the United States and other countries, and a growing pipeline of preclinical research with translational potential, there is great hope for a widely applicable food allergy treatment.

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.

Potential therapies for food allergy: a review

Food allergy is a widespread problem that has been increasing in prevalence in recent years. Avoidance of food allergens is difficult. Food allergic reactions are common and can be severe. Unfortunately, there is little in the way of therapies for food allergy, and strict allergen avoidance remains the standard of care. Several therapeutic approaches are currently being investigated, including subcutaneous, oral, and sublingual immunotherapy, anti-immunoglobulin E therapy, and traditional Chinese medicine. Although results thus far show promise for several of these strategies, further studies are needed to evaluate the safety, efficacy, and long-term outcomes before any food allergy therapies currently under investigation are ready for widespread use in clinical practice.

Food allergy: an enigmatic epidemic

Food allergy is a common disease that is rapidly increasing in prevalence for reasons that remain unknown. Current research efforts are focused on understanding the immune basis of food allergy, identifying environmental factors that may contribute to its rising prevalence, and developing immunotherapeutic approaches to establish immune tolerance to foods. Technological advances such as peptide microarray and MHC class II tetramers have begun to provide a comprehensive profile of the immune response to foods. The burgeoning field of mucosal immunology has provided intriguing clues to the role of the diet and the microbiota as risk factors in the development of food allergy. The purpose of this review is to highlight significant gaps in our knowledge that need answers to stem the progression of this disorder that is reaching epidemic proportions.

Practical approach to nutrition and dietary intervention in pediatric food allergy

Although the need for nutritional and dietary intervention is a common thread in food allergy management, the type of food allergic disorder and the identified food allergen will influence the approach to dietary intervention. A comprehensive nutrition assessment with appropriate intervention is warranted in all children with food allergies to meet nutrient needs and optimize growth. However, dietary elimination in food allergy may also have undesirable consequences. Frequently, an elimination diet is absolutely necessary to prevent potentially life-threatening food allergic reactions. Allergen elimination can also ease chronic symptoms, such as atopic dermatitis, when a food is proven to trigger symptoms. However, removing a food with proven sensitivity to treat chronic symptoms may increase the risk of an acute reaction upon reintroduction or accidental ingestion after long-term avoidance, so it is not without risk. Additionally, it is not recommended to avoid foods in an attempt to control chronic symptoms such as AD and EoE when allergy to the specific food has not been demonstrated. Ultimately, allergen elimination goals are to prevent acute and chronic food allergic reactions in the least restrictive, but also the safest environment to supply a balanced diet that promotes health and growth and development in children.

IgE-mediated cow's milk allergy in children

The age at which the majority of children outgrow cow's milk allergy now appears to be later than previously reported. Recent studies have attempted to elucidate factors that may help prevent cow's milk allergy, assess markers of persistence, and evaluate the usefulness of new diagnostic methods. Strict avoidance of cow's milk has been the mainstay of treatment. However, given the potential nutritional, social, and immunologic ramifications of cow's milk elimination from a child's diet, there has been a focus on reevaluating this therapeutic approach.

The likelihood of remission of food allergy in children: when is the optimal time for challenge?

Although diagnostic testing methods for food hypersensitivity have improved over time, both in vivo and in vitro methods are significantly flawed, especially as evidenced by the frequent occurrence of false-positive test results. Because of these limitations, oral food challenge testing remains an essential element in the diagnosis and management of food allergy. In fact, the double-blind, placebo-controlled food challenge remains the gold standard for the diagnosis of food allergy. In this review, we focus on the optimal timing of oral food challenges, especially for patients with a known food allergy, to determine if the food allergy may have been outgrown.

Vaccines and immunomodulatory therapies for food allergy

The apparent increase in food allergy prevalence has led to a surge in the amount of clinical and basic science research dedicated to the field. At the current time, allergen avoidance remains the cornerstone of treatment; however, recent clinical trials investigating various forms of immunotherapy have opened doors to the possible future application of an active treatment strategy in everyday practice. In addition, improvements in molecular biology have allowed researchers to purify, clone, and modify allergens, thus laying the groundwork for research on vaccines using modified proteins of decreased allergenicity. Finally, various allergen-nonspecific immunomodulatory therapies are also being investigated as a means to alter the immune response to food allergens. With these emerging therapeutic strategies, it is hoped that practitioners will have options in caring for their food-allergic patients in the near future.

Milk processing as a tool to reduce cow's milk allergenicity: a mini-review

Milk processing technologies for the control of cow’s milk protein allergens are reviewed in this paper. Cow’s milk is a high nutritious food; however, it is also one of the most common food allergens. The major allergens from cow’s milk have been found to be β-lactoglobulin, α-lactalbumin and caseins. Strategies for destroying or modifying these allergens to eliminate milk allergy are being sought by scientists all over the world. In this paper, the main processing technologies used to prevent and eliminate cow’s milk allergy are presented and discussed, including heat treatment, glycation reaction, high pressure, enzymatic hydrolysis and lactic acid fermentation. Additionally, how regulating and optimizing the processing conditions can help reduce cow’s milk protein allergenicity is being investigated. These strategies should provide valuable support for the development of hypoallergenic milk products in the future.

Mucosal immunology of tolerance and allergy in the gastrointestinal tract

The mucosal immune system typically exists in a state of active tolerance to food antigens and commensal bacteria. Tolerance to food proteins is induced in part by dendritic cells residing in the intestinal mucosa and implemented by regulatory T cells. Food allergy occurs when immune tolerance is disrupted and a sensitizing immune response characterized by food-specific IgE production occurs instead. Experimental food allergy in mice requires use of adjuvant or exploitation of alternate routes of sensitization to induce allergic sensitization, and can aid in understanding the mechanisms of sensitization to food allergens and the pathophysiology of gastrointestinal manifestations of food allergy. Recent work in the understanding of mucosal immunology of tolerance and allergy in the gastrointestinal tract will be discussed.

Treatments for food allergy: how close are we?

Food allergy continues to be a challenging health problem, with prevalence continuing to increase and anaphylaxis still an unpredictable possibility. While improvements in diagnosis are more accurately identifying affected individuals, treatment options remain limited. The cornerstone of treatment relies on strict avoidance of the offending allergens and education regarding management of allergic reactions. Despite vigilance in avoidance, accidental ingestions and reactions continue to occur. With recent advances in the understanding of humoral and cellular immune responses in food allergy and mechanisms of tolerance, several therapeutic strategies for food allergies are currently being investigated with the hopes of providing a cure or long-term remission from food allergy.

Food allergy: present and future management

Food allergy poses a significant burden on patients, families, health care providers, and the medical system. The increased prevalence of food allergy has brought about investigation as to its cause and new treatments. Currently, the only treatment available is to avoid the food and symptomatically treat any reactions. There are multiple clinical and murine models of food allergy treatment that use allergen specific and nonspecific pathways. Allergen specific treatments use mucosal antigen exposure as a method of inducing desensitization and tolerance. Allergen nonspecific methods act via a more global T_H2 suppressive mechanism and may be useful for those patients with multiple food allergies.

The natural history of milk allergy in an observational cohort

OBJECTIVE

There are few studies on the natural history of milk allergy. Most are single-site and not longitudinal, and these have not identified a means for early prediction of outcomes.

METHODS

Children aged 3 to 15 months were enrolled in an observational study with either (1) a convincing history of egg allergy, milk allergy, or both with a positive skin prick test (SPT) response to the trigger food and/or (2) moderate-to-severe atopic dermatitis (AD) and a positive SPT response to milk or egg. Children enrolled with a clinical history of milk allergy were followed longitudinally, and resolution was established by means of successful ingestion.

RESULTS

The cohort consists of 293 children, of whom 244 were given a diagnosis of milk allergy at baseline. Milk allergy has resolved in 154 (52.6%) subjects at a median age of 63 months and a median age at last follow-up of 66 months. Baseline characteristics that were most predictive of resolution included milk-specific IgE level, milk SPT wheal size, and AD severity (all P < .001). Baseline milk-specific IgG4 level and milk IgE/IgG4 ratio were not predictive of resolution and neither was expression of cytokine-inducible SH2-containing protein, forkhead box protein 3, GATA3, IL-10, IL-4, IFN-γ, or T-bet by using real-time PCR in CD25-selected, casein-stimulated mononuclear cells. A calculator to estimate resolution probabilities using baseline milk IgE level, SPT response, and AD severity was devised for use in the clinical setting.

CONCLUSIONS

In this cohort of infants with milk allergy, approximately one half had resolved over 66 months of follow-up. Baseline milk-specific IgE level, SPT wheal size, and AD severity were all important predictors of the likelihood of resolution.

Oral immunotherapy for food allergy: towards a new horizon

Food allergy has increased dramatically in prevalence over the past decade in westernized countries, and is now a major public health problem. Unfortunately for patients with food allergy, there is no effective therapy beyond food allergen avoidance, and rapid medical treatment for accidental exposures. Recently, oral immunotherapy (OIT) has been investigated as a treatment for this problem. In this review, we will discuss the progress in developing OIT for food allergy, including a novel approach utilizing Xolair (anti-IgE monoclonal antibody, omalizumab) in combination with OIT. This combination may enhance both the safety and efficacy of oral immunotherapy, and could lead to a widely available and safe therapy for food allergy.

The influence of the time and temperature of heat treatment on the allergenicity of egg white proteins

PURPOSE

The present study was performed to determine the factor, either duration or the temperature of heat treatment, exerting maximal and significant influence on the composition and allergenicity of egg white (EW) proteins.

METHODS

Raw EW and 4 kinds of heated EW (fried EW, boiled EW for 10 minutes, boiled EW for 30 minutes, and baked EW for 20 minutes at 170℃) were prepared, and subsequently protein extraction was carried out. The proteins were separated by SDS-PAGE, and then immunoglobulin E (IgE) immunoblots were performed with the sera of 7 egg-allergic patients. Furthermore, the antigenic activities of ovalbumin (OVA), ovomucoid (OM), and ovotransferrin (OT) in different EW samples were measured by inhibition enzyme-linked Immuno-sorbent assay (ELISA).

RESULTS

In SDS-PAGE analysis, the intensity of the protein band at 45 kD (corresponding to OVA) decreased significantly in boiled EW (30 minutes) and baked EW, but no change was observed in the case of boiled EW for 10 minutes. In IgE immunoblots, the IgE response to 34-50 kD (OM and OVA) in boiled EW for 30 minutes decreased significantly, when compared with raw EW and other heated EWs. In inhibition ELISA, a significant decrease in the OVA antigenic activity was observed in boiled EW for 30 minutes amongst other heated EW samples. However, OM antigenic activity in all kinds of heated EW including boiled EW for 30 minutes did not reduce after heat treatment. The OT antigenic activity nearly disappeared in heated EWs except in the case of boiled EW for 10 minutes.

CONCLUSIONS

Amongst 4 kinds of heated EWs, the boiled EW for 30 minutes showed the most significant changes both in composition and reduction in allergenicity. Our results revealed that the duration of heat treatment had more influence on the composition and allergenicity of EW proteins than the temperature.

Dietary baked egg accelerates resolution of egg allergy in children

BACKGROUND

Baked egg is tolerated by a majority of egg-allergic children.

OBJECTIVE

To characterize immunologic changes associated with ingestion of baked egg and evaluate the role that baked egg diets play in the development of tolerance to regular egg.

METHODS

Egg-allergic subjects who tolerated baked egg challenge incorporated baked egg into their diet. Immunologic parameters were measured at follow-up visits. A comparison group strictly avoiding egg was used to evaluate the natural history of the development of tolerance.

RESULTS

Of the 79 subjects in the intent-to-treat group followed for a median of 37.8 months, 89% now tolerate baked egg and 53% now tolerate regular egg. Of 23 initially baked egg-reactive subjects, 14 (61%) subsequently tolerated baked egg and 6 (26%) now tolerate regular egg. Within the initially baked egg-reactive group, subjects with persistent reactivity to baked egg had higher median baseline egg white (EW)-specific IgE levels (13.5 kU(A)/L) than those who subsequently tolerated baked egg (4.4 kU(A)/L; P= .04) and regular egg (3.1 kU(A)/L; P= .05). In subjects ingesting baked egg, EW-induced skin prick test wheal diameter and EW-, ovalbumin-, and ovomucoid-specific IgE levels decreased significantly, while ovalbumin- and ovomucoid-specific IgG(4) levels increased significantly. Subjects in the per-protocol group were 14.6 times more likely than subjects in the comparison group (P< .0001) to develop regular egg tolerance, and they developed tolerance earlier (median 50.0 vs 78.7 months; P< .0001).

CONCLUSION

Initiation of a baked egg diet accelerates the development of regular egg tolerance compared with strict avoidance. Higher serum EW-specific IgE level is associated with persistent baked and regular egg reactivity, while initial baked egg reactivity is not.

Predicting food challenge outcomes for baked milk: role of specific IgE and skin prick testing

BACKGROUND

Cow's milk allergy is the most common food allergy in childhood. Many children with IgE-mediated cow's milk allergy may tolerate baked milk products, but few data exist on predictors of outcomes of baked milk challenges.

OBJECTIVE

To determine the relation of milk protein allergen specific IgE (sIgE) levels and skin prick test (SPT) wheal size with baked milk challenge outcomes.

METHODS

A retrospective medical record review was conducted of 35 baked milk challenges. SPT results, sIgE levels, demographic characteristics, and food challenge results were analyzed.

RESULTS

Thirty-five children underwent open challenges to baked milk and 29 (83%) passed. Of those who failed, 3 (50%) passed the initial clinic challenge but developed symptoms to ongoing exposure at home, days to months later. One child who ultimately failed at home required epinephrine. Compared with those who passed, children who failed were younger (median age, 8.9 and 3.7 years, respectively; P = .02). Children with a milk SPT wheal less than 12 mm were more than 90% likely to pass a baked milk challenge, and no child with a milk SPT wheal less than 7 mm failed a baked milk challenge. We were also able to establish more than 90% predictive values for passing baked milk challenges with a casein SPT wheal of 9 mm, a milk sIgE level of 1.0 kU/L, and a casein sIgE level of 0.9 kU/L.

CONCLUSION

Most children allergic to cow's milk tolerated baked milk. Milk protein SPT wheal may be more reliable than sIgE level in predicting outcomes of baked milk challenges. It is important to be aware of the possibility of late reactions to ongoing baked milk exposure.

Diagnostic approach and management of cow's-milk protein allergy in infants and children: ESPGHAN GI Committee practical guidelines

OBJECTIVES

This guideline provides recommendations for the diagnosis and management of suspected cow's-milk protein allergy (CMPA) in Europe. It presents a practical approach with a diagnostic algorithm and is based on recently published evidence-based guidelines on CMPA.

DIAGNOSIS

If CMPA is suspected by history and examination, then strict allergen avoidance is initiated. In certain circumstances (eg, a clear history of immediate symptoms, a life-threatening reaction with a positive test for CMP-specific IgE), the diagnosis can be made without a milk challenge. In all other circumstances, a controlled oral food challenge (open or blind) under medical supervision is required to confirm or exclude the diagnosis of CMPA.

TREATMENT

In breast-fed infants, the mother should start a strict CMP-free diet. Non-breast-fed infants with confirmed CMPA should receive an extensively hydrolyzed protein-based formula with proven efficacy in appropriate clinical trials; amino acids-based formulae are reserved for certain situations. Soy protein formula, if tolerated, is an option beyond 6 months of age. Nutritional counseling and regular monitoring of growth are mandatory in all age groups requiring CMP exclusion. REEVALUATION: Patients should be reevaluated every 6 to 12 months to assess whether they have developed tolerance to CMP. This is achieved in >75% by 3 years of age and >90% by 6 years of age. Inappropriate or overly long dietary eliminations should be avoided. Such restrictions may impair the quality of life of both child and family, induce improper growth, and incur unnecessary health care costs.

Basophil reactivity, wheal size, and immunoglobulin levels distinguish degrees of cow's milk tolerance

BACKGROUND

In our previous study about 75% of children with cow's milk allergy tolerated baked milk products, which improved their prognosis and quality of life.

OBJECTIVE

We sought to identify biomarkers of varying degrees of clinical tolerance among a cohort of children with cow's milk allergy.

METHODS

One hundred thirty-two subjects were initially classified as baked milk-reactive, baked milk-tolerant, or having "outgrown milk allergy" based on the results of oral food challenges. The baked milk-tolerant group was then divided into 3 groups based on the amount and degree of heat-denatured milk protein that they could tolerate. Serum was analyzed for allergen-specific IgE and IgG(4) levels, basophil reactivity was assessed in whole blood stimulated with serial 10-fold dilutions of milk protein, and skin prick tests (SPTs) were performed to commercial milk extract. Activated basophils were defined by using flow cytometry as CD63(bright)CD203c(+)CD123(+)HLA-DR(dim/-)CD41a(-)lineage(-). Data were analyzed by using the Jonckheere-Terpstra test.

RESULTS

Significant differences across the 5 clinical groups were seen for median casein- and milk-specific IgE levels, casein-specific IgG(4) levels, and casein IgE/IgG(4) ratios; milk-specific to nonspecific basophil activation ratio, median basophil reactivity, and spontaneous basophil activation (CD203c expression after stimulation with RPMI); and milk SPT wheal diameters. Casein- and milk-specific IgE level, milk-specific basophil reactivity, and milk SPT wheal diameter are all significantly greater among patients with milk allergy who react to baked milk than among those who tolerate it.

CONCLUSIONS

The majority of patients with milk allergy are able to tolerate some forms of baked milk in their diets. Different phenotypes of children with cow's milk allergy can be distinguished by casein- and milk-specific IgE levels, milk-specific basophil reactivity, and milk SPT mean wheal diameters. Spontaneous basophil activation is greater among patients with more severe clinical milk reactivity.

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.