Patients suffering from non-IgE-mediated cow's milk protein intolerance cannot be diagnosed based on IgG subclass or IgA responses to milk allergens

Immunoproteomics of cow's milk allergy in Mexican pediatric patients

Immunological mechanisms of non-IgE-mediated cow's milk protein allergy (CMPA) are not well understood. Such a circumstance requires attention with the aim of discovering new biomarkers that could lead to better diagnostic assays for early treatment. Here, we sought both to investigate the mechanism that underlies non-IgE-mediated CMPA and to identify cow's milk immunoreactive proteins in a Mexican pediatric patient group (n = 34). Hence, we determined the IgE and IgG_1-4 subclass antibody levels against cow's milk proteins (CMP) by ELISA. Then, we performed 2D-Immunoblots using as first antibody immunoglobulins in the patients'serum that bound specifically against CMP together with CMP enrichment by ion-exchange chromatography. Immunoreactive proteins were identified by mass spectrometry-based proteomics. The serological test confirmed absence of specific IgE in the CMPA patients but showed significant increase in antigen-specific IgG₁. Additionally, we identified 11 proteins that specifically bound to IgG₁. We conclude that the detection of specific IgG₁ together with an immunoproteomics approach is highly relevant to the understanding of CMPA's physiopathology and as a possible aid in making a prognosis since current evidence indicates IgG₁ occurrence as an early signal of potential risk toward development of IgE-mediated food allergy. SIGNIFICANCE: Allergies are one of the most studied topics in the field of public health and novel protein allergens are found each year. Discovery of new principal and regional allergens has remarkable repercussions in precise molecular diagnostics, prognostics, and more specific immunotherapies. In this context, specific IgE is widely known to mediate physiopathology; however, allergies whose mechanism does not involve this immunoglobulin are poorly understood although their incidence has increased. Therefore, accurate diagnosis and adequate treatment are delayed with significant consequences on the health of pediatric patients. The study of type and subtypes of immunoglobulins associated with the immunoreactivity of cow's milk proteins together with an immunoproteomics approach allows better comprehension of physiopathology, brings the opportunity to discover new potential cow's milk protein allergens and may help in prognosis prediction (IgG₁ occurrence as an early signal of possible risk toward development of IgE-mediated food allergy).

Consensus on the diagnosis and treatment of cow's milk protein allergy of the Latin American Society for Pediatric Gastroenterology, Hepatology and Nutrition

Cow's milk protein allergy (CMPA) is the most frequent cause of food allergy in the first months of life. Despite the fact that there are different guidelines and recommendations on the management of children with CMPA, there continues to be great variability in diagnostic and therapeutic criteria in Latin America. The Food Allergy Working Group of the Latin American Society for Pediatric Gastroenterology, Hepatology and Nutrition summoned a group of Latin American experts to reach a consensus and formulate a document to unify diagnostic and therapeutic criteria for CMPA. Three teams were formed, each with a coordinator, and the members of each team developed a series of statements for their corresponding module: a) clinical manifestations and diagnosis; b) diagnostic tools, and c) treatment. A search of the medical literature was carried out to support the information presented in each module and 28 statements were then selected. The statements were discussed, after which they were evaluated by all the experts, utilizing the Delphi method. Their opinions on statement agreement or disagreement were anonymously issued. The final statements selected were those with above 75% agreement and their corresponding recommendations were formulated, resulting in the document presented herein.

Non-IgE- or Mixed IgE/Non-IgE-Mediated Gastrointestinal Food Allergies in the First Years of Life: Old and New Tools for Diagnosis

non-IgE and mixed gastrointestinal food allergies present various specific, well-characterized clinical pictures such as food protein-induced allergic proctocolitis, food protein-induced enterocolitis and food protein-induced enteropathy syndrome as well as eosinophilic gastrointestinal disorders such as eosinophilic esophagitis, allergic eosinophilic gastroenteritis and eosinophilic colitis. The aim of this article is to provide an updated review of their different clinical presentations, to suggest a correct approach to their diagnosis and to discuss the usefulness of both old and new diagnostic tools, including fecal biomarkers, atopy patch tests, endoscopy, specific IgG and IgG4 testing, allergen-specific lymphocyte stimulation test (ALST) and clinical score (CoMiss).

Fabrication of Microarrays for the Analysis of Serological Antibody Isotypes against Food Antigens

Food intolerance is delayed adverse food reactions which follow consumption of specific foods. The underlying mechanisms are not well understood, but food intolerance is often considered as a type 2 hypersensitivity reaction mediated by immunoglobulin G (IgG) antibody. To understand the causes of food intolerance, it is important to investigate sensitization patterns of food-specific IgGs (sIgG) in relation to dietary patterns and physical conditions. Conventional approaches to measure serological IgGs often require large volumes of serum, thus are not suitable for highly multiplexed assays. To overcome this impracticality, we developed a highly sensitive method to screen the sIgGs and other antibody isotypes against 66 antigens with minimal amount of serums. We prepared a microarray by immobilizing food antigens on activated glass slides. Human sera and their dietary information were obtained from 30 subjects. Aliquots (200 nl) of sera were analyzed against 66 food antigens in parallel. sIgG levels were determined and analyzed in relation to subjects' dietary patterns. The levels of antibody isotypes were also examined to understand the relationship between allergy and food intolerance. The developed microarray showed exceptional performances in antibody screening and demonstrated the potential to be used as an automated assay system.

Reduced IgE and IgG antigenic response to milk proteins hydrolysates obtained with the use of non-commercial serine protease from Yarrowia lipolytica

The aim of the study was to investigate the use of serine protease from Yarrowia lipolytica yeast for reduction of milk proteins allergenicity. Whey protein concentrate (WPC-80), αs-casein and their hydrolysates were analyzed for the capacity to bind IgE and IgG antibodies present in sera from patients with cow milk protein allergy using a competitive ELISA. The hydrolysis of αs-casein and whey protein concentrate contributed to a significant reduction of their immunoreactive epitopes. In case of IgE antibodies, the lowest binding capacity was detected in the 24 h hydrolysates of both proteins in which the inhibition of the reaction was ≤20 and ≤68% for αs-casein and whey protein concentrate respectively. One hour hydrolysis of WPC-80 reduced the protein antigenicity, while the longer time (5 h) might lead to the exposure of new IgE - reactive epitopes.

Molecular Approaches for Diagnosis, Therapy and Prevention of Cow´s Milk Allergy

Cow´s milk is one of the most important and basic nutrients introduced early in life in our diet but can induce IgE-associated allergy. IgE-associated allergy to cow´s milk can cause severe allergic manifestations in the gut, skin and even in the respiratory tract and may lead to life-threatening anaphylactic shock due to the stability of certain cow´s milk allergens. Here, we provide an overview about the allergen molecules in cow´s milk and the advantages of the molecular diagnosis of IgE sensitization to cow´s milk by serology. In addition, we review current strategies for prevention and treatment of cow´s milk allergy and discuss how they could be improved in the future by innovative molecular approaches that are based on defined recombinant allergens, recombinant hypoallergenic allergen derivatives and synthetic peptides.

Detection of serum and salivary IgE and IgG1 immunoglobulins specific for diagnosis of food allergy

Given the growing incidence and prevalence of life-threatening food allergies, health concerns have raised new perspectives for in vivo and in vitro diagnostic methodologies, pointing to saliva as a promising material, already used to diagnose other pathologies. Based on the above considerations, this study aimed to verify the possible use of saliva for the detection of IgE and IgG₁ in the diagnosis of food allergy. This was a randomized, cross-sectional clinical study with a quantitative approach, developed at a hospital referral center in allergy in the state of Ceará, from January to July 2015. The sample consisted of 36 children of both sexes, aged between 1 and 60 months, with a diagnosis of cow's milk protein allergy (CMPA) by the RAST test. Children hospitalized or under immunosuppressive drugs were excluded from the study. Serum and saliva samples of the participants were collected and subsequently subjected to the indirect immunoenzymatic assay (ELISA) for the detection of specific serum and salivary immunoglobulins for food: corn, papaya, cow's milk, egg white, wheat, soybeans, peanuts, nuts, kiwi, cacao, fish, shrimp, bananas and tomatoes. For comparison of serum and saliva results, the T-test of independent samples and Mann-Whitney were adopted, for samples with normal and non-normal distribution respectively. A confidence interval of 95% was adopted for significant results. It was observed that 100% (n = 36) of the participants presented cow's milk allergy through the indirect ELISA, detecting IgE or IgG₁ in serum and saliva. When serum IgE and IgG₁ concentrations were compared, there was no statistical difference (p > 0.05) in 12 of the 14 foods evaluated. The same amount (n = 12) of non-significant differences (p > 0.05) was observed in the comparison of the 14 foods under IgE and IgG₁ contractions in saliva. In the verification of the average values of IgE present in the serum and saliva of the foods, only cow's milk, fish and papaya showed statistically significant differences (p < 0.05). Of the total food evaluated, only the average levels of IgG₁ present in serum and saliva showed a significant value (p < 0.05) in banana and tomato. These findings indicate that the detection of IgE and IgG₁ in saliva proves to be as efficient as in the serum. The use of the salivary technique for use in the diagnosis of food allergy is suggested.

Important and specific role for basophils in acute allergic reactions

IgE‐mediated allergic reactions involve the activation of effector cells, predominantly through the high‐affinity IgE receptor (FcεRI) on mast cells and basophils. Although the mast cell is considered the major effector cell during acute allergic reactions, more recent studies indicate a potentially important and specific role for basophils and their migration which occurs rapidly upon allergen challenge in humans undergoing anaphylaxis. We review the evidence for a role of basophils in contributing to clinical symptoms of anaphylaxis and discuss the possibility that basophil trafficking during anaphylaxis might be a pathogenic (to target organs) or protective (preventing degranulation in circulation) response. Finally, we examine the potential role of basophils in asthma exacerbations. Understanding the factors that regulate basophil trafficking and activation might lead to new diagnostic and therapeutic strategies in anaphylaxis and asthma.

Anti-food and anti-microbial IgG subclass antibodies in inflammatory bowel disease

OBJECTIVES

Inflammatory bowel disease (IBD), particularly Crohn's disease (CD), is associated with increased microbial-specific IgG and IgA antibodies, whereas alterations of anti-food antibodies are still disputed. The knowledge about IgG subclass antibodies in IBD is limited. In this study we analysed IgG subclass antibodies specific for nutritional and commensal antigens in IBD patients and controls.

METHODS

Serum IgG1, IgG2, IgG3 and IgG4 specific for wheat and milk extracts, purified ovalbumin, Escherichia coli and Bacteroides fragilis lysates and mannan from Saccharomyces cerevisiae were analysed by ELISA in patients with CD (n = 56), ulcerative colitis (UC; n = 29), acute gastroenteritis/colitis (n = 12) as well as non-inflammatory controls (n = 62).

RESULTS

Anti-Saccharomyces cerevisiae antibodies (ASCA) of all IgG subclasses and anti-B. fragilis IgG1 levels were increased in CD patients compared to UC patients and controls. The discriminant validity of ASCA IgG2 and IgG4 was comparable with that of ASCA pan-IgG and IgA, whereas it was inferior for ASCA IgG1/IgG3 and anti-B. fragilis IgG1. Complicated CD defined by the presence of perianal, stricturing or penetrating disease phenotypes was associated with increased ASCA IgG1/IgG3/IgG4, anti-B. fragilis IgG1 and anti-E. coli IgG1 levels. Anti-food IgG subclass levels were not different between IBD patients and controls and did not correlate with food intolerance. In contrast to anti-microbial Abs, food-specific IgG responses were predominately of the IgG4 isotype and all food-specific IgG subclass levels correlated negatively with age.

CONCLUSION

Our study supports the notion that the adaptive immune recognition of food and commensal antigens are differentially regulated.

Role of immunoglobulin G antibodies in diagnosis of food allergy

This paper presents current views on the role of immunoglobulin G (IgG) antibodies in the reactions with food antigens in the digestive tract and their role in the diagnosis of food allergy based on the assays of specific IgG class antibodies, with a special focus on contemporary practice guidelines. In the light of current scientific knowledge, the IgG-specific antibody-mediated reactions are a body's natural and normal defensive reactions to infiltrating food antigens, which are considered as pathogens. On the other hand, specific IgG antibodies against food allergens play a crucial role in the induction and maintaining of immunological tolerance to food antigens. The statements of many scientific societies stress that sIgG are of no significant importance in the diagnosis of food allergy since their presence is associated with a normal immune response to food allergens and attests to a protracted exposure to food antigens.

Assessment of IgE and IgG4 Binding Capacities of Cow's Milk Proteins Selectively Altered by Proteases

Specific IgE and IgG4 have been reported to play key roles in the context of IgE-mediated cow's milk allergy (CMA), but the persistence of their epitopes in milk hydrolysates has not been evaluated. Using sera from 32 CMA patients, 6 CMA patients treated by epicutaneous therapy (CM-treated), and 4 CM-tolerant peanut allergic patients, we analyzed the IgE and IgG4 binding capacities related to major milk allergens in processed milk. Different proteases (plasmin, chymosin, α-chymotrypsin, or pepsin) were used progressively and selectively to hydrolyze β-lactoglobulin (β-LG) and casein (CN) in milk. We then showed that proteases differentially affect IgE or IgG4 immunoreactivities of CN and β-LG and also that we could not relate IgE and/or IgG4 levels or specificities to milk hydrolysates to the clinical status of the patients.

Development of a surface display ELISA to detect anti-IgG antibodies against bovine αS1-casein in human sera

The aim of the present study was to develop a surface display ELISA (SD-ELISA) for IgG-serum reaction against bovine casein αS1 (CSN1S1). In a SD-ELISA, the antigen is displayed on the surface of Escherichia coli using the autodisplay technology and whole cells of E. coli are used to coat the microplates for serum testing. After establishing the setup of the SD-ELISA with polyclonal rabbit antiserum against bovine CSN1S1, the SD-ELISA was validated with 20 human sera, of which 10 sera were proven to have an IgG-mediated reaction against bovine CSN1S1 and 10 sera were shown to be negative for this reaction. Receiver operating characteristics (ROC) analysis revealed sensitivity of 100% and a specificity of 100% at a cut-off value of 0.133. Furthermore, human serum of 48 patients with known reactivity against human CSN1S1 (31 positive and 17 negative) was examined by the newly developed SD-ELISA to exclude cross-reactivity. Twenty human sera showed an IgG-mediated reaction against bovine CSN1S1. Eleven of these sera were positive for the reactivity against human CSN1S1, and nine were negative. In conclusion it was demonstrated that the performance of SD-ELISA is comparable to established ELISA without loss in sensitivity or specificity. Based on the advantages of this method - in particular no need for time-consuming and expensive antigen production and purification - the SD-ELISA is a potent alternative to convenient methods for identification and especially high-throughput screening of new antigens in the field of food allergies.

Food-specific serum IgE and IgG reactivity in dogs with and without skin disease: lack of correlation between laboratories

BACKGROUND

Despite conflicting data on their utility and no reports on interlaboratory reproducibility, serum food-specific antibodies are commonly assayed in first-opinion canine practice.

HYPOTHESIS/OBJECTIVES

To determine both the variability of test results between two laboratories and the frequencies and magnitudes of food reactivity in dogs of different disease status.

ANIMALS

Sera were obtained from eight dogs with cutaneous adverse food reaction (Group A), 22 with nonfood-induced atopic dermatitis (Group B), 30 with an allergic/inflammatory phenotype (Group C), 12 with miscellaneous skin diseases (Group D) and nine healthy dogs (Group E).

METHODS

Paired sera were submitted to two laboratories (A and B) for assays of food-specific IgE and IgG antibodies.

RESULTS

Numbers of positive IgE and IgG tests determined by each laboratory in Groups A, B, D and E were comparable (Group C not included). Significant differences in the magnitude of IgE reactivity between groups for each allergen were seen only for lamb (Laboratory A, P = 0.003); lamb reactivity in Group D exceeded Group E (P = 0.004) but was comparable between all other groups. Agreement (kappa statistic) between the two laboratories' tests was 'moderate' for one antigen (potato IgE), 'fair' for four (corn IgE, rice IgE and IgG and soya bean IgG), 'slight' for eight (six IgE and two IgG) and 'less than chance' for the remaining six antigens (three IgE and three IgG).

CONCLUSIONS AND CLINICAL IMPORTANCE

These laboratories' tests appear to have dubious predictive clinical utility because they neither correlate nor distinguish between dogs of different disease status.

The relationship of food intolerance and irritable bowel syndrome in adults

The purpose of this literature review is to develop a thorough understanding of the research on food intolerance and its relationship to irritable bowel syndrome. Knowledge of the connection between the two conditions will assist allied healthcare professionals in working with patients to better manage their symptoms. Reduced healthcare costs may also result if patients are able to identify problematic foods and experience symptom improvement with diet changes. The review consists of an overview of food intolerance including prevalence, specific foods implicated including an in-depth review of research on bulk sweeteners, as well as methods of diagnosis. In addition, prevalence, specific foods associated with food intolerance in irritable bowel syndrome patients such as carbohydrates and lipids, nutritional consequences of food intolerance, and possible food-related methods of treatment including increased fiber intake are discussed. Finally, suggestions for future research and possible directions allied healthcare professionals can start with in assisting patients are provided.

Markers of gut mucosal inflammation and cow's milk specific immunoglobulins in non-IgE cow's milk allergy

Background

Allergy to cow’s milk protein (CMP) may cause gastrointestinal (GI) symptoms in the absence of CMP specific IgE. The immunological mechanisms involved in such disease are not fully understood. Therefore we examined markers of gut mucosal inflammation and the immunoglobulin profiles in children with Gl symptoms suspected of cow’s milk protein allergy (CMPA).

Patients and methods

We prospectively recruited infants and young children (n = 57; median age 8.7 months) with gastrointestinal complaints suspected of CMPA. The diagnosis of CMPA was made using the double-blind, placebo-controlled food challenge. Serum and stool samples were collected during CMP-free diet and after both placebo and active challenges. We analyzed the stool samples for calprotectin, human β-defensin 2 and IgA. In serum, we analyzed the levels of β-lactoglobulin and α-casein specific IgA, and IgG antibodies (total IgG and subclasses IgG1 and IgG4). Control group included children with e.g. dermatological or pulmonary problems, consuming normal diets.

Results

Fecal calprotectin levels were higher in the challenge positive group (n = 18) than in the negative (n = 37), with respective geometric means 55 μg/g [95% confidence interval 38–81] and 29 [24–36] μg/g (p = 0.0039), during cow’s milk free diet. There were no significant inter-group differences in the fecal β-defensin and IgA levels. The CMP specific IgG and IgA were not elevated in patients with CMPA, but the levels of β-lactoglobulin-IgG4 (p = 0.0118) and α-casein-IgG4 (p = 0.0044), and total α-casein-IgG (p = 0.0054) and -IgA (p = 0.0050) in all patient samples (regardless of CMPA diagnosis) were significantly lower compared to the control group using dairy products.

Conclusions

Despite cow’s milk elimination in children intolerant to cow’s milk there might be ongoing low-grade inflammation in the gut mucosa. CMP specific IgG or IgA should not be used to diagnose non-IgE CMPA. The observed frequency of impaired CMP specific total IgA, IgG and IgG4 production in patients following cow’s milk free diet warrants further studies.

Advances in allergen-microarray technology for diagnosis and monitoring of allergy: the MeDALL allergen-chip

Allergy diagnosis based on purified allergen molecules provides detailed information regarding the individual sensitization profile of allergic patients, allows monitoring of the development of allergic disease and of the effect of therapies on the immune response to individual allergen molecules. Allergen microarrays contain a large variety of allergen molecules and thus allow the simultaneous detection of allergic patients' antibody reactivity profiles towards each of the allergen molecules with only minute amounts of serum. In this article we summarize recent progress in the field of allergen microarray technology and introduce the MeDALL allergen-chip which has been developed for the specific and sensitive monitoring of IgE and IgG reactivity profiles towards more than 170 allergen molecules in sera collected in European birth cohorts. MeDALL is a European research program in which allergen microarray technology is used for the monitoring of the development of allergic disease in childhood, to draw a geographic map of the recognition of clinically relevant allergens in different populations and to establish reactivity profiles which are associated with and predict certain disease manifestations. We describe technical advances of the MeDALL allergen-chip regarding specificity, sensitivity and its ability to deliver test results which are close to in vivo reactivity. In addition, the usefulness and numerous advantages of allergen microarrays for allergy research, refined allergy diagnosis, monitoring of disease, of the effects of therapies, for improving the prescription of specific immunotherapy and for prevention are discussed.

Egg-white-specific IgA and IgA2 antibodies in egg-allergic children: is there a role in tolerance induction?

BACKGROUND

Decreased serum food-specific IgA antibodies have been associated with allergic disease in cross-sectional, case-control studies. The purpose of this study was to prospectively compare egg-white-(EW)-specific IgA and IgA2 levels between egg-allergic children and children tolerating egg.

METHODS

Seventeen egg-allergic children were followed prospectively. Total IgA, EW-specific IgA, and EW-specific IgA2 levels were measured in their sera with a sensitive ELISA. As negative controls were used children with no previous history of egg allergy. Egg-allergic children with or without concomitant milk allergy were evaluated as additional controls with measurement of casein-specific IgA.

RESULTS

After 2.5 ± 0.9 yrs, nine out of the 17 allergic children became tolerant and eight remained allergic to baked egg. Baseline EW-specific IgA2 levels were significantly lower in the egg-allergic subjects (median 23.9 ng/ml) compared with the negative control subjects (99.4 ng/ml) and increased significantly by 28% over the study time period in eight out of the nine allergic children that became tolerant to baked egg. There was no significant change over time in EW-specific IgA in any of the study groups. Non-milk-allergic subjects with concomitant egg allergy had almost threefold higher casein-specific IgA levels than the milk- and egg-allergic subjects (p = 0.025).

CONCLUSIONS

These results suggest a potential role for allergen-specific IgA2 antibodies in the induction of food tolerance. Furthermore, they support the hypothesis that immature or impaired production of allergen-specific IgA2 may be associated with the pathophysiology of food allergy, a defect that seems to be selective for the culprit allergen.

Serum allergen-specific IgA is not associated with natural or induced tolerance to egg in children

The role of specific IgA (sIgA) in oral immunotherapy (OIT) and natural tolerance to foods is poorly understood. We aimed to study serum sIgA in induced and natural tolerance to egg. Children aged 5-16 years diagnosed with IgE-mediated egg allergy were recruited. After egg challenge, patients were classified as transient (TEA) or persistent (PEA) egg-allergic. PEA children were further divided into oral immunotherapy (PEA-OIT) or egg avoidance (PEA-EA). Allergy/tolerance was reassessed 9-12 months later (T1) in PEA-EA. Serum sIgA to ovalbumin and ovomucoid were determined at inclusion in all patients and repeated in PEA at T1. 21 TEA and 52 PEA children were recruited (28 PEA-OIT, 24 PEA-EA). Serum sIgA remained unchanged after OIT. TEA and PEA had similar serum sIgA. No specific trend on serum sIgA was observed in five PEA-EA who developed natural tolerance over follow-up. Thus, serum sIgA seems not to be associated with induced or natural egg tolerance.

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.

Tolerance of a cow's milk-based hydrolyzed formula in patients with eosinophilic esophagitis triggered by milk

BACKGROUND

Cow's milk protein, a major food trigger for EoE in both children and adults, should be continuously avoided once identified as such. This study evaluates tolerance of a cow's milk-based extensively hydrolyzed formula (eHF) with regard to disease remission maintenance in adult patients with milk-triggered EoE.

METHODS

Seventeen adult patients in whom cow's milk was consecutively demonstrated to trigger EoE after an empiric six-food elimination diet-based study protocol and who subsequently maintained disease remission were prospectively recruited. They were given 400 ml of a cow's milk-based eHF daily for 8 weeks. Intraepithelial peak eosinophil and blood eosinophil counts, esophageal-related symptoms, serum total and specific IgE to major milk proteins, and eosinophil cationic protein were monitored before and after eHF intake.

RESULTS

Thirteen male and four female patients aged 17-56 completed the study protocol. 15 patients (88.24%) achieved and maintained EoE remission, while an infiltration of ≥15 eosinophils/hpf reappeared in the remaining two patients. No differences in age, gender, symptoms, and endoscopic appearance at baseline conditions or personal/family allergic background were observed between those patients who tolerated the eHF and those who did not. Symptom scores did not significantly change after eHF intake and were significantly lower than those documented at baseline conditions or after cow's milk challenge. No differences were documented in blood eosinophil counts or serum markers after eHF intake.

CONCLUSION

Most adult patients with EoE triggered by cow's milk tolerate a cow's milk-based eHF, thus providing them with a safe, economical alternative to cow's milk.

A combined biochemical, biophysical and immunological approach towards the identification of celiac disease-specific wheat antigens

Celiac disease (CD) is an inflammatory affliction of the small bowel caused by an immunological hypersensitivity to ingested wheat antigens affecting almost 1 % of the population. The gliadin fraction of wheat has been shown to contain the pathogenic antigens which react with antibodies and T cells. However, there is only limited knowledge regarding the precise nature of the wheat antigens recognized by IgA antibodies from CD patients and diagnostic tests based on the gliadin fraction have been demonstrated to give frequently false positive results. The aim of this study was the characterization of wheat antigens specifically recognized by IgA antibodies of CD patients. We developed a combined biochemical, biophysical, and immunological approach for the identification of celiac disease-specific wheat antigens. It is based on sub-fractionation of the wheat gliadin fraction using two ion exchange chromatography steps, the localization of CD-specific antigens by immunoblotting with IgA antibodies from CD patients, subsequent digestion followed by electro spray ionization-liquid chromatography/mass spectrometry (LC-ESI-MS/MS) and N-terminal sequencing by Edman degradation. Through the sub-fractionation procedure it was possible to separate CD-specific IgA-reactive wheat antigens from other wheat antigens which were also recognized by IgA antibodies of individuals without CD or by CD patients on gluten-free diet. Analysis by LC-ESI-MS/MS and N-terminal sequencing of the sub-fractions and the proteins specifically recognized by CD patients identified certain γ-gliadins with molecular mass of 37,000 and 45,000 as CD-specific wheat antigens. The CD-specific γ-gliadins with the molecular mass of 37,000 and 45,000 should be useful to study pathomechanisms of the disease and to improve the specificity of diagnostic tests for CD.

Guidelines change the diagnostic process of cow milk food allergy: problem-based learning

PURPOSE OF REVIEW

The accurate diagnosis of food allergy and its management has been the subject of two published guidelines, the National Institute of Health Sponsored Expert Panel Guidelines and the World Allergy Organization guidelines: Diagnosis and Rationale for Action Against Cow Milk Allergy. Both guidelines have drawn attention to the unique aspects of different food allergens. They have highlighted the possible overdiagnosis and underdiagnosis of food allergy. The purpose of this review is to demonstrate the utility and application of the two published guidelines in a real-life scenario that the pediatrician or allergy/immunology specialist may be faced with.

RECENT FINDINGS

This review is divided into two sections: the first section is problem-based learning, presenting a clinical scenario of a child suspected of cow milk allergy (CMA) and followed over time. At each step, the guidelines are consulted and referenced. The second section reviews recent research that demonstrates that CMA has a high prevalence, and that testing methodologies can be improved on.

SUMMARY

Clinicians taking the approach outlined by the guidelines will be able to confirm or refute a diagnosis of CMA, all the while minimizing unnecessary tests and procedures.

Variable food-specific IgG antibody levels in healthy and symptomatic Chinese adults

Background

The presence of food-specific IgG antibodies in human serum may be useful for diagnosis of adverse food reactions. However, the clinical utility of tesing for such antibodies remains very controversial. The aim of this study was to evaluate the serum levels and population distribution of food-specific IgGs and their association with chronic symptoms in a large-scale Chinese population.

Methodology/Principal Findings

A total of 21305 adult participants from different regions of China had 14 type of food-specific serum IgG antibodies that were measured by enzyme-linked immunosorbent assay. Amongthese, 5,394 participants were randomly chosen to complete follow-up questionnaire surveys on their dietary characteristics and chronic symptoms. The concentrations of food-specific IgGs against 14 foods ranged from a median (interquartile range) of 7.3 (3.8, 12.6) U/mL of pork-specfic IgG to 42.3 (28.8, 60.2) U/mL of crab-specific IgG. The concentration of food-specific IgGs was closely related to gender; after adjustment for region and age, women had higher concentrations of food-specific IgGs against all of the 14 foods except chicken (regression coefficient (95% CI): 0.01 (−0.003, 0.023); P = 0.129) and corn (0.002 (−0.013, 0.016); P = 0.825). Similar results were also found in the relationship of geographic region to the food-specific IgG concentrations for the 14 foods. Chronic symptoms were negatively associated with the concentrations of a few food-specific IgGs, and were positively associated with the concentrations of other food-specific IgGs.

Conclusions

The levels of food-specific IgGs were variable both in healthy and in symptomatic Chinese adults. These findings raise awareness that demographic factors, the type of food and specific chronic symptoms should be considered before food elimination treatment based on IgG testing in patients with chronic symptoms is used in clinical practice.

Cow's milk and ovalbumin-specific IgG and IgA in children with eczema: low β-lactoglobulin-specific IgG4 levels are associated with cow's milk allergy

Tolerance to allergens may partly depend on allergen-specific IgG and IgG subclasses and IgA antibodies. We investigated whether specific IgG and IgG subclasses and IgA antibodies to β-lactoglobulin, α-casein, and ovalbumin differed between infants who had verified cow's milk allergy (CMA) and infants with cow's milk (CM)-associated eczema, but negative CM oral challenge. The study population comprised 95 infants with clinical eczema that was by history associated with the consumption of CM. After an elimination period, a double-blind, placebo-controlled (DBPC) CM oral challenge confirmed CMA in 45 infants. Skin prick tests (SPT) were performed with CM and hen's egg. Serum levels of IgE antibodies to CM and hen's egg were measured with UniCAP (Phadia, Uppsala, Sweden), and levels of IgA, IgG, IgG1, and IgG4 antibodies to β-lactoglobulin, α-casein, and ovalbumin were measured with enzyme-linked immunosorbent assay. We observed that infants with CMA had lower IgG4 levels to β-lactoglobulin than infants with negative DBPC CM challenge (p = 0.004). Positive CM SPT was associated with lower IgG4 levels to α-casein (p = 0.04). The relation of CM IgE to β-lactoglobulin and α-casein IgG4 was higher in CMA than in infants with negative challenge (p < 0.002 and 0.0001). Positive egg SPT was associated with elevated levels of specific IgG to ovalbumin, β-lactoglobulin, and α-casein as well as IgA to α-casein (p < 0.04). Our study thus shows that low β-lactoglobulin-specific serum IgG4 levels may differentiate eczematous infants with CMA from infants who have eczema with only suspected association with CM.

Characteristics of patients suffering from cow milk allergy

The most frequent symptoms among the manifestations of cow milk allergy (CMA) are gastrointestinal. CMA pathogenesis involves immunological mechanisms with participation of immunocompetent cells, production of immunoglobulin E (IgE) and immunoglobulin G (IgG). We aim to determine whether cow milk-specific IgE antibodies coexist with cow milk-specific IgG antibodies in CMA patients with diarrhea symptom, and if there is any relationship between both antibody types. 65 CMA patients (average age of 17 years, ranging from 2 to 74 years), all of who had diarrhea symptom of CMA, were enrolled in this study. The total cow IgE and IgG subclass in serum were measured by electrochemiluminescence immunoassay and rate immune scatter turbidimetry, respectively. And also the cow milk-specific IgE was determined by enzyme-linked immunosorbent assay. The number of eosinophils in serum was calculated by Sysmex XE-2100 Hematology Analyzer. Our data showed that both cow milk-specific IgG and IgE levels were significantly elevated in CMA patients compared to those of age-matched control subjects. Out of the 65 CMA patients, 40 showed elevated cow milk-specific IgE antibody level, among which, 28 cases presented highly sensitive reaction to cow milk-specific IgG, along with each six of moderate and mild sensitive reaction to cow milk-specific IgG; while 20 showed elevated total IgG levels. The IgG3 positive rate was 16.9%, which was the highest. A moderate correlation between cow milk-specific IgE and cow milk-specific IgG was found in the CMA patients (r=0.415, P=0.001). The results indicated that cow milk-specific IgE antibodies could coexist with cow milk-specific IgG antibodies in patients suffering from CMA. The aberrant changes in the concentration of cow milk-specific IgE antibodies were associated with cow milk-specific IgG antibodies.