Allergy to quail's egg without allergy to chicken's egg. case report

INTRODUCTION

We present a case of quail's egg allergy without allergy to chicken's egg.

CASE

Girl of 10.5 years old who presents anaphylactic reaction after she ate an uncooked quail's egg. She had eaten boiled quail's egg before. She eats chicken's eggs without clinical symptoms.

METHODS

We made a prick to chicken's egg and prick-by-prick to uncooked quail's and raw chicken's egg. We determined specific IgE to chicken's egg; electrophoresis and IgE by immunoblot to eggs from chicken, duck, goose, and quail.

RESULTS

We obtained negative results to prick, prick-by-prick and specific IgE to chicken's egg. Prick-by-prick to quail's egg was positive. By immunoblot we recognised a protein in quail's egg white, which is ovotransferrin without any similar bands in other species' eggs.

CONCLUSIONS

The protein that we recognised is a specific protein of quail's egg. These proteins did not cross-react with proteins of chicken's egg. Cooking may degrade such proteins.

[Usefulness of skin prick test using bifurcated needle for the diagnosis of food allergy in infantile atopic dermatitis--1st report. Case of egg allergy]

OBJECTIVE

We investigated the usefulness of skin prick test (SPT) for the diagnosis of egg white (EW) allergy in infants with atopic dermatitis who showed negative to EW CAPRAST, and followed up the EW-CAPRAST in this study.

SUBJECTS AND METHODS

Data of negative SPT using Bifurcated needle (BN) were analyzed from the data of 202 atopic dermatitis infants, who had received SPT from January in 2001 to April in 2005. From the negative SPT value (average and standard deviation) positive SPT value was obtained. Among 202 cases, 89 suspected-egg allergy infants with negative IgE CAPRAST against EW at the time of first visit were recruited to examine the usefulness of SPT. Positive conversion of EW-CAPRAST was checked in 78 cases (65: egg allergy+, 13: egg allergy(-)) who had been followed up in our outpatient clinic.

RESULTS

Range of negative SPT control value (mean+2SD) using BF among infants could be set as less than 2 mm for wheal and/or 5 mm for erythema. Among 89 suspected-egg allergy infants with negative EW-CAPRAST, 72 infants (80.9%) were diagnosed as egg allergy by the combination of elimination and provocation test, interestingly 39 infants (54.2%) showed positive SPT results. In the follow up study of 78 negative EW-CAPRAST cases, 47 EW-CAPRAST out of 65 egg-allergy cases turned positive later infantile period (mean EW-CAPRAST: 9.6+/-16.7 Ua/ml at 9.9+/-5.6 months old). EW-CAPRAST of 7 cases in 13 non-egg allergies also turned positive in the follow up, however EW-CAPRAST titer was relatively lower compared to that of egg allergies (1.1+/-1.5 Ua/ml at 13.3+/-2.6 months old).

CONCLUSIONS

We experienced fairly number of atopic infants with negative EW-CAPRAST at the first outpatient visit, who were later diagnosed as egg allergy. In about half of these cases, SPT egg-allergy infants, three quarter of EW-CAPRAST turned positive around 10 months old. EW-CAPRAST of atopic infants without egg allergy also turned transiently and slightly positive. In the conclusions, SPT seemed to be more useful than EW-CAPRAST for the diagnosis of egg allergy in early infantile period, however provocation test should be required for the definitive diagnosis in suspected-egg allergy infants without any proof of egg-sensitization.

Prevalence of egg sensitization in Turkish infants based on skin prick test

AIM

Egg allergy is one of the most frequent allergies in infants. The aim of this study was to determine the frequency of sensitization to egg in infants based on skin prick test results and to evaluate associated allergic conditions by questionnaire.

METHODS

All infants born between June 2001 and May 2002 were recalled to the hospital according to their dates of birth, and 1015 infants aged between 8-18 months were included in the study. An interview was conducted with each mother and a questionnaire requesting data on food allergy and other allergic diseases was completed during this interview. An egg skin prick test (whole egg) was applied to all infants.

RESULTS

Positive skin prick test results were recorded in 19 infants (1.87 %). There was no difference between the prick test-positive and -negative groups with respect to any of the demographic characteristics investigated (gender, age, birth weight, egg consumption, age of introduction of egg and other solids, breastfeeding). No significant association was demonstrated between sensitization to egg and family history of allergy. Moreover, there was no association between sensitization to egg and occurrence of atopic dermatitis, recurrent wheezing, gastrointestinal symptoms and doctor diagnosis of asthma.

CONCLUSION

The prevalence of egg sensitization based on skin prick test results has been found as 1.87 % among Turkish infants in Istanbul. However, no significant relationship was found between allergic sensitization to egg and occurrence of allergic diseases in this study population.

Frequent IgE sensitization to latex, cow's milk, and egg in children with short bowel syndrome

Children with short bowel syndrome (SBS) undergo frequent operations, so they are at risk for sensitizing to latex. There have been isolated reports of sensitization to food in these children. In a cross-sectional study, we assessed sensitization to latex, cow's milk, and egg with skin prick tests (SPT) and serum-specific immunoglobulin E (IgE) in 14 children with SBS. Data were collected about the number of operations with latex devices, serum total IgE, and history of feeding with milk formula. Ten children were sensitized to latex (specific IgE median: 6.7 kU/l, range: 0.5-33). Compared with those non-sensitized, sensitized children had significantly (p < 0.05) higher levels of serum total IgE in z-units (mean rank 3.25 vs. 9.2, respectively), and more operations with latex devices (mean rank 3.75 vs. 9). Eight children were sensitized to cow's milk, one with only positive SPT, the other seven with serum-specific IgE (median: 3.5, range: 0.5-21.1 kU/l), and five to egg (specific IgE median: 0.68, range: 0.58-2.17 kU/l). Except for some isolated days with cow's milk formula, the children had been initially fed with a diet without intact cow's milk proteins. Sensitization to latex, cow's milk, and egg is very frequent in children with SBS. They should be treated in a latex-free environment since the very early stages of the disease, and should be routinely studied regarding food sensitization, as this might contribute as an added factor in the chronic diarrhea of these patients.

Patterns of immunoglobulin G responses to egg and peanut allergens are distinct: ovalbumin-specific immunoglobulin responses are ubiquitous, but peanut-specific immunoglobulin responses are up-regulated in peanut allergy

BACKGROUND

The clinical significance of food-specific IgG subclasses in food allergy and tolerance remains unclear. Specific IgG titres are often reported in non-standardized units, which do not allow comparisons between studies or allergens.

OBJECTIVE

To quantify, in absolute units, ovalbumin (OVA)- and peanut-specific IgG levels in children with peanut or egg allergy (active or resolved) and in non-allergic controls. Methods Children aged 1-15 years were recruited. Peanut allergy was diagnosed by convincing history and a 95% predictive level of specific IgE; egg allergy or resolution was confirmed by oral challenge. Serum IgG, IgG1 and IgG4 levels (microg/mL) to OVA and peanut extract were quantified by ELISA.

RESULTS

OVA- and peanut-specific IgG was detected in all subjects. In non-allergic controls (n=18), OVA-specific IgG levels were significantly higher than peanut-specific IgG (median microg/mL IgG=15.9 vs. 2.2, IgG1=1.3 vs. 0.6, IgG4=7.9 vs. 0.7; P<0.01). There were no differences in OVA-specific IgG, IgG1 and IgG4 between egg-allergic (n=40), egg-resolved (n=22) and control (n=18) subjects. In contrast, peanut-specific IgG (median microg/mL IgG=17.0, IgG1=3.3, IgG4=5.2) were significantly higher in peanut-allergic subjects (n=59) compared with controls and with non-peanut-sensitized but egg-allergic subjects (n=26). Overall, the range of IgG4 was greater than IgG1, and IgG4 was the dominant subclass in >60% of all subjects.

CONCLUSION

OVA-specific IgG levels of egg-allergic, egg-resolved or control groups are not distinguishable. Higher peanut-specific IgG levels are associated with clinical allergy, but the range of IgG titres of the allergic and control groups overlapped. Hence, OVA and peanut-specific IgG measurements do not appear to be of diagnostic value. Strong IgG responses to OVA may be a normal physiological response to a protein frequently ingested from infancy, whereas up-regulated IgG responses in peanut allergy may be indicative of a dysregulated immune response to peanut allergens.

Specific oral tolerance induction in food allergy in children: efficacy and clinical patterns of reaction

BACKGROUND

Specific oral tolerance induction (SOTI) seems to be a promising treatment of food allergy. Specific oral tolerance induction and elimination diet were compared with respect to efficacy rate and patterns of clinical reaction.

METHODS

Children with challenge proven immunoglobulin E (IgE)-mediated cow's milk (CM) allergy or hen's egg (HE) allergy were randomly assigned to SOTI or elimination diet as a control group. Specific oral tolerance induction treatment was performed at home on a daily basis according to a study protocol with fresh CM or lyophilized HE protein. Re-evaluation of clinically relevant food allergy was performed by food challenge after a median of 21 months. Children in the SOTI group received a secondary elimination diet for 2 months prior to follow-up challenge to evaluate persistence of induced oral tolerance.

RESULTS

At follow-up challenge, nine of 25 children (36%) showed permanent tolerance in the SOTI group, three of 25 (12%) were tolerant with regular intake and four of 25 (16%) were partial responders. In the control group, seven of 20 children (35%) were tolerant. Allergen-specific immunoglobulin E decreased significantly both in children who developed natural tolerance during the elimination diet (P < 0.05) and in those with SOTI (P < 0.001).

CONCLUSIONS

Specific oral tolerance induction seems a valid treatment option for patients with persistent food allergy. Indications may be given if avoidance cannot be guaranteed or for those who are eager to eat the food in question. Advantages of SOTI are the increased threshold dose for allergic reactions and the substantially reduced risk of severe allergic reactions after inadvertent ingestion of the allergen. However, careful monitoring during SOTI is mandatory.

Genetically glycosylated ovomucoid third domain can modulate Immunoglobulin E antibody production and cytokine response in BALB/c mice

BACKGROUND

Food allergies are on the rise and it is estimated that in North America, 8% of the children and 4% of the adults have food allergies. Food allergies tend to occur more often in children than in adults due to their immature digestive and immune systems. Hen's egg is among the most common cause of food-induced allergic reactions in North America.

OBJECTIVE

The present study was undertaken to investigate the role of N-glycans of the third domain of ovomucoid in IgE binding and modulation of allergen-specific immune response in BALB/c mice.

METHODS

The cDNA encoding the third domain of ovomucoid was inserted into the yeast genome and expressed in Pichia pastoris X-33 cells, under the control of the glyceraldehyde-3-phosphate (GAP) dehydrogenase promoter for constitutive expression to obtain a post-translationally modified and functionally active ovomucoid third domain. Upon expression, the protein was secreted into the extracellular medium and was purified by size exclusion chromatography. The recombinant protein was produced at 10 mg/L of the culture supernatant. BALB/c mice were sensitized with the recombinant and native forms of glycosylated ovomucoid third domain antigen. The allergic response of the native and the recombinant glycosylated forms of ovomucoid third domain antigens were compared using antibody and cytokine measurements.

RESULTS

ELISA tests indicated a significant decrease in specific IgE antibodies to the recombinant N-linked glycosylated form (P-Gly), when compared with the native glycosylated form (DIII+) using mice sera. Immunization with P-Gly induced the production of IFN-gamma [T-helper type 1 (Th1) response] and lowered the production of IL-4 (Th2 response), and a skewed balance towards the Th1 cytokine demonstrated that P-Gly has a modulating ability on Th1/Th2 balance to down-regulate Th2 response. Furthermore, N-linked glycan (N28) in the third domain of ovomucoid was shown to be associated with suppression of the allergic response.

CONCLUSION

Therefore, we can conclude that P-Gly facilitates and contributes to the discovery of new molecular target for the development of a safe and specific therapeutic vaccine for the treatment of egg allergy, and oligosaccharides do seem to play a major role in the suppression of IgE-binding activity.

Food allergy and asthma morbidity in children

BACKGROUND

Coexisting food allergy and asthma is a significant problem in the pediatric population. Studies have looked at the association between food sensitization and asthma severity. It is unknown whether specific food allergies are associated with increased asthma morbidity.

OBJECTIVE

We studied the independent effect that allergy to egg, milk, fish, and peanut has on the number of hospitalizations and courses of systemic steroids in children with asthma.

METHODS

We performed a medical record review to evaluate the effect food allergy to egg, fish, peanut, and milk has on asthma morbidity. We reviewed the records of 201 children aged 3 months to 14 years with the diagnosis of asthma (ICD-9 codes 493.90, 493.91, and 493.92), of which 88 had coexistent food allergy. All children in the food allergy group had food-specific IgE concentrations greater than the 95% positive predictive value. We compared the rate of hospitalizations and use of systemic steroids between children with asthma and food allergies and those without coexisting food allergy using direct-entry, multiple regression analysis. Patients were adjusted for the severity of their asthma based on symptoms documented at their first visit to the allergist according to the National Asthma Education and Prevention Program guidelines and presence of environmental allergy, eczema, smoke exposure, and gastroesophageal reflux.

RESULTS

Peanut and milk allergies were both associated with increased number of hospitalizations (P=0.009, 0.016), and milk allergy was associated with increased use of systemic steroids (P=0.001).

CONCLUSION

Peanut and milk allergies were associated with increased hospitalization and steroid use and may serve as early markers for increased asthma morbidity.

Safety of measles-mumps-rubella vaccine (MMR) in patients allergic to eggs

INTRODUCTION

Since the measles and mumps components used in MMR vaccine are grown in cultures of fibroblast from chick embryos, for a long time there have been concerns about the presence of egg protein in the vaccine and the recommendations given to egg allergic patients. We include in this paper our clinical experience vaccinating egg allergic patients with a regular triple viral vaccine, as well as an immunological study of each vaccine available in Spain. The aim of this study was to evaluate the clinical safety of a conventional MMR vaccine in a population of egg allergic patients and to determine the presence of egg allergens in a conventional MMR vaccine and if IgE antibodies from egg allergic can recognize egg allergens in this vaccine.

MATERIALS AND METHODS

Children 15 months old with a confirmed diagnosed of egg allergy were included. In all patients, a skin prick test with non diluted MMR vaccine (Priorix, GSK) was made. If negative, each patient received a single dose of measles, mumps, rubella (MMR) vaccine. If positive, a fractionated injection of the vaccine was made following SEICAP recommendations (2004). SDS-PAGE immunoblotting was performed with Priorix vaccine.

RESULTS

A cumulative total of 26 patients with egg allergy have safely received MMR vaccine in a single-dose (after a negative SPT in all cases) at our department without any reaction. 5 sera of vaccinated patients and 6 control sera of egg allergic patients (positive oral challenge) were used to immunolabel the membranes. No positive bands corresponding to egg proteins were found in any of the patients.

CONCLUSION

Negative results found in SPT support the absence of clinical reaction against the components and Immunological studies point that there is no detectable amount of egg protein in this vaccine to produce an IgE mediated reaction. We can conclude that MMR can be safely administrated in children allergic to egg.

Egg allergy: are all childhood food allergies the same?

Egg allergy is one of the most common food allergies in childhood affecting about 1-2% of preschool children and differs in a number of ways from other common childhood food allergies such as cows milk and peanut. Common egg allergens are altered both by heat and gastric enzymes. Compared with peanuts/tree nuts and milk, egg allergy appears less likely to cause severe life-threatening reactions or fatal anaphylaxis. Children are much more likely to outgrow egg allergy by school age as compared with peanut allergy. While the MMR vaccine is no longer contraindicated in egg allergy, influenza vaccine is contraindicated in children with anaphylaxis to egg. An understanding of the similarities and differences in these common food allergies of childhood is helpful in the management of these common and increasing problems.

New onset egg allergy in an adult

We report newly presenting systemic and local allergic reactions to egg in a 55-year-old woman. The patient did not have a history of egg allergy in childhood or occupational exposure to egg proteins; nor did she report any disease that is known to be related to food allergy. A skin prick test with commercial extracts, prick-to-prick test, CAP radioallergosorbent assay, and a double-blind, placebo-controlled food challenge test were used to prove egg allergy. Because egg allergy mainly affects children and symptoms frequently disappear with age, the late onset in this patient is rare.

Quantifying serum antibody in bird fanciers' hypersensitivity pneumonitis

Background

Detecting serum antibody against inhaled antigens is an important diagnostic adjunct for hypersensitivity pneumonitis (HP). We sought to validate a quantitative fluorimetric assay testing serum from bird fanciers.

Methods

Antibody activity was assessed in bird fanciers and control subjects using various avian antigens and serological methods, and the titer was compared with symptoms of HP.

Results

IgG antibody against pigeon serum antigens, quantified by fluorimetry, provided a good discriminator of disease. Levels below 10 mg/L were insignificant, and increasing titers were associated with disease. The assay was unaffected by total IgG, autoantibodies and antibody to dietary hen's egg antigens. Antigens from pigeon serum seem sufficient to recognize immune sensitivity to most common pet avian species. Decreasing antibody titers confirmed antigen avoidance.

Conclusion

Increasing antibody titer reflected the likelihood of HP, and decreasing titers confirmed antigen avoidance. Quantifying antibody was rapid and the increased sensitivity will improve the rate of false-negative reporting and obviate the need for invasive diagnostic procedures. Automated fluorimetry provides a method for the international standardization of HP serology thereby improving quality control and improving its suitability as a diagnostic adjunct.

Food antigen causes TH2-dependent enteropathy followed by tissue repair in T-cell receptor transgenic mice

BACKGROUND

Clarification of the mechanisms underlying the development of food-sensitive intestinal inflammation will provide an important clue to combating food allergies.

OBJECTIVE

To establish a model of intestinal inflammation caused by oral administration of antigen without additional treatments, we focused on the ovalbumin (OVA) 23-3 T-cell receptor transgenic mouse, which had been reported to have high serum antigen-specific IgE responses to the feeding of an egg white diet.

METHODS

Changes in body weight of mice fed an egg white diet were monitored throughout the 28-day experimental period. After the 28-day feeding, intestinal tissues were harvested for histologic examination. Endogenous production of cytokines and histamine in the jejunum, and production of cytokines secreted by OVA-specific CD4+ T cells purified from mesenteric lymph nodes, were analyzed.

RESULTS

Egg white diet-fed OVA23-3 mice developed weight loss and inflammation with villous atrophy and goblet cell hyperplasia, especially in the jejunum. A further characteristic feature was evidence of weight recovery and tissue repair. Jejunal inflammation was also observed in egg white diet-fed recombination activating gene (RAG)-2-deficient OVA23-3 mice. In addition, tissue sections revealed significant infiltration of specific IgE-positive cells and IgE-positive degranulating mast cells. Higher levels of IL-4 and significant levels of histamine were detected in the tissues. In the supernatant of OVA-stimulated T cells, IL-10 levels were also markedly elevated.

CONCLUSION

We report that high-dose and continuous intake of primitive OVA alone induces enteropathy containing regions under repair in OVA23-3 mice. Antigen-specific T cells and inflammatory cells primed by T(H)2 responses play important roles in regulation of development and improvement of the disease.

CLINICAL IMPLICATIONS

Long-term antigen intake causes T(H)2-dependent and food-sensitive enteropathy followed by tissue repair.

Natural course of sensitization to hen's egg in children not previously exposed to egg ingestion

BACKGROUND

Clinical adverse reactions to egg may occur in infants or children who have never eaten egg. They may be sensitized or even react at first egg ingestion. Few studies are available concerning the reality of egg white allergy in such sensitized children, the natural evolution of this condition and the appropriate decisions to make.

OBJECTIVES

To analyze the actuality and natural course of egg allergy in children sensitized without previous of hen's egg ingestion.

METHODS

We set up a clinical decision tree based on clinical history and specific egg white IgE to manage patients who had never ingested egg but were sensitized as demonstrated by a positive SPT and report a cohort of 30 such children

RESULTS

The mean level of egg white specific IgE at first analysis, i.e. before 12 months, was high, 28.3 KU(A) /L, with a large range, from 0.6 to >100 KU(A) /L, below 6 KU(A) /L in only 8 patients. In 6 children ("no challenge" group), IgE values remained >8 KU(A) /L by the end of the survey and the oral challenge with egg was always denied. Their mean + SD IgE level was at 51.7 + 38 KU(A) /L at 1 year and 19.7 + 13 KU(A) /L at a mean age of 34 + 5 months. All had an associated anaphylactic reaction with milk and 5 were still allergic to milk by the end of the survey. In the remaining 24 infants, egg was given for the first time at a mean age of 30 + 9 months, by error in 4 cases, all exhibiting an immediate reaction, and in a hospital setting in 20, among whom 14 reacted. Among those 18, with a specific IgE level at 9.1 + 10 KU(A) /L at 28 + 9 months, 4 became tolerant between 3 and 4 years, with specific IgE levels below 1.3 KU(A) /L and a 5th one with specific IgE >100 KU(A) /L at 6 months tolerated scrambled eggs at age 7 year, with specific IgE at 2.6 KU(A) /L. In the 6 others, labeled "non allergic", egg white specific IgE levels were significantly lower, whatever the age, than in the "no challenge" group. The age at challenge was 35 + 8 months, with a mean specific IgE level at 1.0 + 0.9 KU(A) /L.

CONCLUSION

In children sensitized to egg without previous ingestion of that food, egg tolerance appears probably in some by the age of 3 but may reveal much more prolonged in a limited number.

[Cow's milk allergy: guidelines for the diagnostic evaluation]

About 2% of the general population and up to 6% of children suffer from food allergy. Cow's milk is charged with a important role in infancy after weaning, since conventional formula are based on its procession. IgE-mediated and Non-IgE- mediated allergic reactions, which are different in manifestation and pathogenesis, can be distinguished. A special role play the exacerbation of atopic dermatitis and the gastrointestinal-food-hypersensitivity-reactions. Skin-prick-test and determination of specific IgE are important diagnostic tools beside medical history. The golden standard of diagnosis is the double-blind-placebo-controlled-food- challenge. The clear result from food-challenge allows to verify suspected food allergies or, on the other hand, to avoid unnecessary diets. Extensively-hydrolysed-formula or Amino-acidformula are a high nutritional value alternative in case of proved cow's milk allergy in infancy.

Skin prick test to egg white provides additional diagnostic utility to serum egg white-specific IgE antibody concentration in children

BACKGROUND

Levels of IgE antibody to egg white of greater than 7 kIU/L are highly predictive of clinical reactivity to egg, and lower levels often require evaluation with oral food challenge (OFC) to establish definitive diagnosis. OFCs have inherent risks, and diagnostic criteria indicating high likelihood of passing would be clinically useful.

OBJECTIVE

We sought to determine whether the size of the skin prick test (SPT) to egg white adds diagnostic utility for children with low egg white-specific IgE antibody levels.

METHODS

A retrospective analysis of clinical history, egg white-specific IgE antibody levels, SPT responses, and egg OFC outcomes was performed.

RESULTS

Children who passed (n = 29) egg OFCs and those who failed (n = 45) did not differ significantly in age, clinical characteristics, or egg white-specific IgE levels. There were, however, significant differences between both egg white SPT wheal response size and egg/histamine SPT wheal index. Children who failed egg OFCs had a median wheal of 5.0 mm; those who passed had a median wheal of 3.0 mm (P = .003). Children who failed egg OFCs had a median egg/histamine index of 1.00; those who passed had a median index of 0.71 (P = .001). For egg white-specific IgE levels of less than 2.5 kIU/L, an SPT wheal of 3 mm or an egg/histamine index of 0.65 was associated with a 50% chance of passing.

CONCLUSION

In children with low egg white-specific IgE levels, those with smaller SPT wheal responses to egg were more likely to pass an egg OFC than those with larger wheal responses. The size of the egg white SPT response might provide additional information to determine the timing of egg OFC.

CLINICAL IMPLICATIONS

The size of the egg white SPT wheal response might provide the clinician with additional information to determine the timing of egg OFC in children with low egg white-specific IgE antibody levels.

[Feature of food allergy developed during infancy (1)--relationship between infantile atopic dermatitis and food allergy]

BACKGROUND

Most of food allergy (FA) cases during childhood start as infantile atopic dermatitis (AD) at the ages of a few months old. We tried to clarify the association between infantile AD and FA during infancy.

METHODS

We analyzed relationship between AD and FA during infancy among patients with 208 cases, who had visited our outpatient clinic with chief complaint of "eczema" from 1998 to 2000.

RESULTS

Among 208 cases, 148 cases (71%) were diagnosed as infantile AD, moreover 109 cases (74%) were diagnosed as FA among infantile AD. The most frequent food antigens among infantile AD were egg (72.3%), cow's milk (39.9%), wheat (12.2%) and soybean (7.4%), respectively, in addition to these food antigens, food allergy was widely recognized against peanuts, sesame, meats, buckwheat, fishes and potato. In terms of food antigen, 44 cases with single food allergy against egg were seen out of 46 single allergy cases, whereas 36 cases with double food allergy against both egg and cow's milk were seen in 63 multiple food allergy cases. Although the value of antigen specific IgE against egg and cow's milk was recognized for the diagnosis of food allergy during infancy, even cases with negative IgE against those foods were proved to be food allergy by food elimination and provocation tests. In contrast to egg and cow's milk, positive IgE against rice, soybean, and wheat did not always correlate with the results of the diagnosis of food allergy. Concerning risk factors of AD, family history of any allergy diseases and passive smoking were recognized in comparison with infantile eczema. Neither the nutrition method nor incomplete elimination of diet during pregnancy and lactation had anything to do with the development of AD.

CONCLUSION

When infantile AD cases were not improved by environmental control, skin care and application of steroid ointment, it would be important for doctors to think of the possibility of FA.

Time course of total and food specific IgE antibodies (Rast Fx5) in the developing allergic child

AIM

To analyze the evolution of total and food specific IgE (Rast Fx5) titers in the course of food allergy in children.

PATIENTS & METHODS

925 children, mean age 8.9 + 9.1 years (15 days-18 years), 455 girls and 470 boys, investigated for food allergy in year 1997, underwent serum samples assay for total IgE and of Rast Fx5, Cap System, Pharmacia & Upjohn Diagnostics AB, Uppsala, Sweden, a mix test detecting specific IgE to 6 major food allergens in children, cow's milk proteins (CMP), egg white, peanut, soy, wheat and fish and analyzed as a function of reference values by age.

RESULTS

Total IgE titers increased significantly with age, r0.22, p0.0001. The percentage of children with a total IgE level above normal range first increased with age, from 10.3 % at 0-6 months, reaching 38.2 % at 1-2 years and peaking at 56.9% at 4-6 years, then leveled off, 48.1% at 8-12 years (ns vs 4-6 years) and 41.3% above 12 years (ns). Detectable Rast Fx5 increased in a parallel manner until age 4-6 years and then exhibited a progressive decrease from age 6-8 years, differing significantly from total IgE: 31.9% vs 52.9%, p0.01 (6-8 years), 32.2% vs 48.1%, p0.03 (8-12 years), 21.8% vs 41.3%, p0.05 (> 12 years).

CONCLUSION

In these outpatient children investigated for food allergy, the increase with age of the percentage of high total IgE contrasted with the progressive decrease of Rast Fx5 from age 4-6 yr. This biological finding correlates timely with the clinical spontaneous decrease of food allergy in the developing child.

Detection of four distinct groups of hen egg allergens binding IgE in the sera of children with egg allergy

BACKGROUND

There appears to be a lack of agreement in the literature on the allergenicity of hen egg proteins. This may be partly due to the use of impure proteins in some cases. Egg yolk proteins have also been largely ignored in such studies. We therefore set out to determine, using especially purified proteins, their relative allergenicity, and to observe whether there were any relationships between their potency and the sensitivity of patients to them.

METHODS AND RESULTS

The sera of 40 patients with clinically observed hen egg hypersensitivity were tested for specific IgE binding to purified egg white and egg yolk proteins using the radioallergosorbent test (RAST). Statistical treatment by correspondence analysis of the percent radioactive uptakes in the RAST to the 8 proteins demonstrated that there were four distinct groups of patients reacting in a similar way to four discrete sets of proteins.

CONCLUSIONS

The first three sets of allergens consisted of egg white proteins as follows: firstly, lysozyme and ovalbumin; secondly, ovomucoid; and thirdly, ovomucin. The fourth set contained the egg white protein ovotransferrin and the egg yolk proteins apovitellenins I and VI and phosvitin. The existence of patient groups may explain why various workers have reported different allergens to be important in egg hypersensitivity. A sufficiently large number of patients must be examined so as to give a representative distribution across each group, otherwise the results may be biased towards one allergen.

Novel ELISA for the detection of raw and processed egg using extraction buffer containing a surfactant and a reducing agent

Enzyme-linked immunosorbent assay (ELISA) has been considered extremely useful for the detection of markers of allergenic substances in food, because it is simple, offers a suitable sensitivity, and is useful in providing quantitative results. Allergenic protein present in processed food can be denatured or altered, hindering therefore their possibility to be extracted and detected. This paper reports the development of an ELISA method that can be used for the determination of allergenic proteins in buffer solutions containing SDS, a surfactant, and 2-mercaptoethanol, a reducing agent. Measurement by ELISA in solutions containing 1% SDS and 7% 2-mercaptoethanol has been made possible by using an antibody prepared through immunization with an antigen denatured with SDS and 2-mercaptoethanol. This ELISA technique can be used to measure proteins in food that have been denatured by various manufacturing processes. An example is egg white albumin, which is susceptible to heat denaturation and has been difficult to recover from food in the past. Its recovery was improved 10- to 100-fold by the new ELISA method as compared with previous methods. This means that allergenic substances in food can now be detected quantitatively. This method can be very useful in allergy prevention and control strategies.

[Allergenic activity of non-calcinated egg shell calcium]

BACKGROUND

There is few data to prove the safety of egg shell calcium as allergen. Especially, non-calcinated egg shell calcium is not allowed to use without the description of origin of egg on food labels in Japan.

METHOD

We evaluated the possibly contaminated egg allergens in commercial non-calcinated egg shell calcium made from egg by in vitro methodologies (SDS-PAGE, western blotting, inhibition ELISA and sandwich ELISA) and by single-blind oral non-calcinated egg shell calcium challenge on 6 egg hypersensitivity patients.

RESULTS

The allergenic activity of non-calcinated egg shell calcium was almost negligible compared to egg white by all in vitro methods. Furthermore, six patients with egg hypersensitivity were unresponsive to oral non-calcinated egg shell calcium challenge test.

CONCLUSION

These results indicate that there is little contamination of egg white in non-calcinated egg shell calcium, and that the allergenic activity of non-calcinated egg shell calcium is equivalent to that of calcinated egg shell calcium.

The predictive value of specific immunoglobulin E levels in serum for the outcome of oral food challenges

BACKGROUND

Specific serum IgE is considered as one of the important diagnostic measures in the diagnostic work-up of food allergy.

OBJECTIVE

To evaluate the role of specific serum IgE in predicting the outcome of oral food challenges, and to determine threshold concentrations of specific serum IgE that could render double-blind, placebo-controlled food challenges unnecessary.

METHODS

In 501 children (median age 13 months), 992 controlled oral challenges were performed with cow's milk (CM), hen's egg (HE), wheat and soy. 440/501 (88%) children suffered from atopic dermatitis. For all children, specific IgE concentrations in serum were determined. Sensitivity, specificity, positive and negative predictive values, receiver operator characteristics-curves as well as predictive decision points were calculated.

RESULTS

Four hundred and forty-five out of 992 oral food challenges with allergens were assessed as positive. Sensitivity of specific serum IgE was 97% for HE, 83% for CM, 69% for soy, and 79% for wheat. Specificity was 51% for HE, 53% for CM, 50% for soy, and 38% for wheat. Calculating 90%, 95% and 99% predicted probabilities using logistic regression revealed predictive decision points of 6.3, 12.6, and 59.2 kU/L for HE, respectively. Subdividing our children in those of below or above 1 year of age resulted in a markedly different predicted probability for HE. For CM, only the 90% predicted probability (88.8 kU/L) could be calculated. No decision points could be determined for CM, wheat and soy.

CONCLUSION

In general, specific serum IgE levels showed a correlation with the outcome of positive oral food challenges for CM and HE. Meaningful predictive decision points can be calculated for HE, which may help to avoid oral food challenges in some cases. However, data need to be ascertained for each allergen separately. Furthermore, the age of the patient population under investigation must also be taken into account.

Characterization of T-cell clones specific to ovomucoid from patients with egg-white allergy

BACKGROUND

Allergic reactions to foods are specific problems for infants and young children. Ovomucoid (OM) is one of the major allergens found in egg-white. We previously established several T-cell clones (TCCs) specific to OM in non-polarizing conditions from 4 patients (TM and YN are immediate-type, IH and YT are non-immediate-type) with egg-white allergy. We characterized their reactive epitopes, antigen-presenting molecules (HLA class II), and usage of TCR alpha and beta genes and the CDR3 loop sequence.

OBJECTIVE

The objective of this study was to characterize these seven clones (TM 1.3, TM1.4,YN 1.1, YN1.5, IH3.1, IH3.3 and YT6.1) for cytokine production patterns and cell-surface-marker phenotypes.

METHODS

We measured the production of cytokines, namely interleukin (IL)-4, IL-5 and interferon-gamma (IFN-gamma) by stimulation with ovomucoid peptides and stained intracellular IL-4 and IFN-gamma, and determined cell-surface markers using anti-interleukin-12 receptor (IL-12R) beta1, anti-IL-12Rbeta2 and anti-interleukin-18 receptor alpha (IL-18Ralpha).

RESULTS

Most TCCs secreted both IL-4 and IFN-gamma in response to the OM peptide mixture, but the secretion patterns were variable; an IFN-gamma dominant pattern was seen in IH3.1 andYT6.1, an IFN-gamma>IL-4 pattern in TM1.3 and TM1.4, an IL-4> IFN-gamma pattern in YN1.5. In intracellular IFN-gamma and IL-4 staining, IFN-gamma single-positive cells were predominant in TM1.3, TM1.4, IH3.1 and YT6.1 and IFN-gamma and IL-4 double-positive cells were predominant in YN1.1, YN1.5 and IH3.3. All TCCs were IL-12Rbeta1-positive, and TM1.3, IH3.1, IH3.3 and YT6.1 were both IL-12Rbeta2- and IL-18Ralpha-positive. TM1.4 and YN1.1 were both IL-12Rbeta2- and IL-18Ralpha-negative. Based on these results, TM1.3 and TM1.4, IH3.1 and YT6.1 had a predominantly Th1 character and YN1.1, YN1.5, and IH3.3 possessed a predominantly Th0 character.

CONCLUSIONS

The phenotypes of TCCs were not in accordance with their clinical manifestations. TCCs established from patients with immediate-type hypersensitivity had either the Th1 or Th0 phenotype as well as those with non-immediate-type hypersensitivity.

The use of patch testing in the diagnosis of food allergy

Diagnosing food allergies can be challenging to the practitioner. Our armamentarium includes standardized skin prick testing, radioallergoimmunosorbent (RAST) testing, and food challenges. These methods have certainly been helpful in the IgE-mediated disorders, including urticaria and anaphylaxis. However, diagnosing patients who have the non-IgE (cell-mediated) or mixed (IgE and cell-mediated) disorders remains challenging with our current diagnostic methods. Recent studies have examined the use of patch testing for these food-allergic patients, specifically those with atopic dermatitis and eosinophilic esophagitis. In this article, we review literature regarding patch testing: its methods, its statistical usefulness, and its potential future role.

Determination of food specific IgE levels over time can predict the development of tolerance in cow's milk and hen's egg allergy

BACKGROUND

The majority of children with cow's milk and hen's egg allergy develop clinical tolerance with time. However, there are no good indices to predict when and in whom this occurs.

OBJECTIVE

The aim of this study was to determine if monitoring food specific IgE levels over time could be used as a predictor for determining when patients develop clinical tolerance.

METHODS

Eighty-eight patients with hen's egg and 49 patients with cow's milk allergy who underwent repeated double-blind, placebo-controlled food challenges were included in the study. Using the Pharmacia CAP-System FEIA, specific IgE (sIgE) levels to cow's milk and hen's egg were retrospectively determined from stored serum samples obtained at the time of the food challenges. Logistic regression was used to evaluate the relationship between tolerance development and the decrease in sIgE levels over a specific time period between the two challenges.

RESULTS

Twenty-eight of the 66 egg-allergic and 16 of the 33 milk-allergic patients lost their allergy over time. For egg, the decrease in sIgE levels (P=.0014) was significantly related to the probability of developing clinical tolerance, with the duration between challenges having an influence (P=.06). For milk there also was a significant relationship between the decrease in sIgE levels (P=.0175) and the probability of developing tolerance to milk but no significant contribution with regard to time. Stratification into 2 age groups, those below 4 years of age and those above 4 years of age at time of first challenge, had an effect, with the younger age group being more likely to develop clinical tolerance in relation to the rate of decrease in sIgE. The median food sIgE level at diagnosis was significantly less for the group developing "tolerance" to egg (P <.001), and a similar trend was seen for milk allergy (P=.06). Using these results, we developed a model for predicting the likelihood of developing tolerance in milk and egg allergy based on the decrease in food sIgE over time.

CONCLUSION

We found that the rate of decrease in food sIgE levels over time was predictive for the likelihood of developing tolerance in milk and egg allergy. Using the likelihood estimates from this study could aid clinicians in providing prognostic information and in timing subsequent food challenges, thereby decreasing the number of premature and unnecessary double-blind, placebo-controlled food challenges.

Update on threshold doses of food allergens: implications for patients and the food industry

PURPOSE OF REVIEW

The purpose of this review is to bring the reader up to date on the importance of assessing a food's lowest observed adverse-effect level (LOAEL) with two aims. Firstly, to help industry choose tests with a level of sensitivity capable of detecting food allergens hidden in industrial products. Secondly, to specify protective measures for highly allergic individuals in order to prevent recurrent severe anaphylaxis. The review also seeks to highlight the present issues and unsolved questions.

RECENT FINDINGS

Thanks to standardized oral-provocation tests (double-blind placebo-controlled food challenges), LOAELs have been identified for many IgE-dependent food allergies. Most studies concern the pediatric population. Data is available for milk, egg, peanut, wheat flour, and sesame. The LOAELs are commonly in the range of 1-2 mg of natural foods, representing a few hundred micrograms of protein. These minimal reactive doses characterize about 1% of people allergic to milk, egg, or peanut. The level at which no observed adverse effect is seen might be a few tens of micrograms of protein for peanut. At the present time, allergy to oil seems to be restricted to unrefined cold-pressed oils.

SUMMARY

Concerning IgE-dependent food allergies, the threshold dose inducing symptoms is now known to vary a great deal according to the individual. A reactive dose of less than 65 mg characterizes 16 and 18% of patients allergic to egg or peanut. Less than 30 mg of milk proteins characterizes 5% of those allergic to milk. For milk, egg, and peanut, 1% of patients have a very low threshold, about 1 mg. Such data emphasize the necessity of using detection tests with a sensitivity better than 10 parts per million. The modifications of allergenicity undergone by protein ingredients that are now commonly introduced into industrially made products are not yet sufficiently known. A better knowledge of the reactive doses of these proteins is needed.

Specific IgE levels do not indicate persistence or transience of food allergy in children with atopic dermatitis

BACKGROUND

Food allergy in early childhood usually resolves with time; however, little is known about predictors for persistence or transience of food allergy in children with atopic dermatitis. The aim of the study was to evaluate whether specific IgE levels in serum could be a useful predictor of the outcome of oral re-challenges.

METHODS

In 74 children, 99 oral food challenges were performed (cow milk n = 48, hen egg n = 37, and wheat n = 14) and repeated after a median time interval of 16 months. In 15 of the 74 children, a third challenge (n = 22) could be performed, with a median time interval from second challenge to third challenge of 15 months.

RESULTS

There were 37 children with transient food allergy (positive first challenge and negative second challenge), while 62 children had persistent food allergy (positive first challenge and negative second challenge). Comparison of the two groups showed that specific IgE as well as total IgE in serum was significantly higher in the latter group. However, looking at the time course, specific IgE did not decrease significantly during elimination diet.

CONCLUSION

Our results indicate that specific IgE in serum--although very helpful at the time of the first diagnosis--cannot predict whether a chid will become tolerant after a period of avoidance. Therefore, oral re-challenges remain mandatory.

[Diarrhea as manifestation of allergic diseases. The difficult search for the allergen]

Allergy is a very uncommon cause of diarrhoea. Other mechanisms, medical diseases and infections, psychological and pseudoallergic reactions, intolerance reactions, and enzyme defects/deficiency, and many other conditions are much more common. If food allergy is strongly suspected diagnosis may be difficult, even for allergologists, as it requires a mosaic of history, skin and in vitro tests, diagnostic diet, and even provocation tests. It is important to recognise diarrhoea "accompanying" allergic urticaria and anaphylactic reactions as part of the symptomatology of the primary dermatological or allergic disease and to refer the patient to the appropriate specialist.

Immunization of egg-allergic individuals with egg- or chicken-derived vaccines

Viruses used in several vaccines are propagated in embryonated eggs. These vaccines contain variable quantities of residual egg or chicken proteins and pose risks when administered to egg- or chicken-sensitive persons. This article highlights differences in how vaccines are prepared, with emphasis on the quantitation of residual egg-derived protein in each vaccine. Published reports on the frequency and severity of these vaccine-induced allergic reactions are reviewed, and an algorithm is provided for the preimmunization evaluation of egg-sensitive persons.

Fine mapping and structural analysis of immunodominant IgE allergenic epitopes in chicken egg ovalbumin

Ovalbumin is a major allergen in hen egg white that causes IgE-mediated food allergic reactions in children. In this study, the immunodominant IgE-binding epitopes of ovalbumin were mapped using arrays of overlapping peptides synthesized on activated cellulose membranes. Pooled human sera from 18 patients with egg allergy were used to probe the membrane. Five distinct regions were found to contain dominant allergic IgE epitopes, these being L38T49, D95A102, E191V200, V243E248 and G251N260. The critical amino acids involved in IgE antibody binding were also determined. These epitopes were composed primarily of hydrophobic amino acids, followed by polar and charged residues and being comprised of beta-sheet and beta-turn structures. One epitope, D95A102, consisted of a single alpha-helix. These results provide useful information on the functional role of amino acid residues to evaluate the structure-function relationships and structural properties of allergic epitopes in ovalbumin. They also provide a strategic approach for engineering ovalbumin to reduce its allergenicity.

Possible modes of allergen-specific sensitization and boosting in an atopic child

Several studies document that allergen-specific IgE levels are boosted by allergen contact via the respiratory tract in allergic patients. Only few data are available on whether other routes of allergen contact have an influence on systemic IgE responses. We report the case of a boy who developed egg allergy after heavy consumption of eggs by the mother during pregnancy and breast feeding. In contrast to other children who outgrow egg allergy during the first years of life, the boy experienced further dramatic increases in hen egg-specific IgE antibodies after prolonged consumption of ostrich eggs containing cross-reactive allergens. IgE antibodies to most of the important respiratory allergens remained either low or not detectable. The dramatic increases in hen egg-specific IgE antibody levels after oral intake of allergens demonstrate that systemic IgE responses in allergic patients can be strongly boosted by allergen contact via routes other than the respiratory tract.

Study on the Prevention of Allergy in Children in Europe (SPACE): allergic sensitization at 1 year of age in a controlled trial of allergen avoidance from birth

Several studies have demonstrated that early intervention may modulate the natural course of atopic disease. The objective of this study was to prevent sensitization to house dust mite and food allergens, as well as development of atopic symptoms, during infancy. To achieve this we employed the combination of an educational package with the use of mite allergen-impermeable mattress encasings. A multi-center European, population-based, randomized controlled study of children at increased atopic risk [study on the prevention of Allergy in Children in Europe (SPACE)] was performed in five countries (Austria, Germany, Greece, Great Britain, Lithuania) and included three cohorts of schoolchildren, toddlers and newborns. We report on the newborn cohort. A total of 696 newborns were included in Austria, Great Britain and Germany. Inclusion criteria were a positive history of parental allergy and a positive skin-prick test or specific immunoglobulin E (IgE) of >or= 1.43 kU/l against at least one out of a panel of common aeroallergens in one or both parents. At 1 year of age the overall sensitization rate against the tested allergens [dust mite allergens: Dermatophagoides pteronyssinus and D. farinae (Der p and Der f, respectively)] and food allergens (egg, milk) in the prophylactic group was 6.21% vs. 10.67% in the control group. The prevalence of sensitization against Der p was 1.86% in the prophylactic group vs. 5% in the control group. In conclusion, we demonstrated, in a group of newborns at risk for atopic diseases, that the sensitization rate to a panel of aero- and food allergens could be effectively decreased through the use of impermeable mattress encasings and the implementation of preventive measures that were easy to perform.

A comparison of different allergometric tests, skin prick test, Pharmacia UniCAP and ADVIA Centaur, for diagnosis of allergic diseases in children

BACKGROUND

The diagnosis of allergic disease is performed by skin prick tests (SPT) or through the demonstration of specific IgE in a blood sample via an in vitro test. The measurement of IgE concentration against allergens provides critical information in clinical allergy. Standardized and reproducible methods contribute to the quality of diagnosis and treatment of allergic disease.

METHODS

In this study we evaluated the performance of a new specific IgE method, developed by ALK-Abellò for Bayer Diagnostics to run on their ADVIA Centaur immunoassay system. One hundred and fifty-one children with allergic diseases (both food and inhalant allergies) were tested for specific IgE (sIgE) via SPT and in vitro tests (UniCAP system, Pharmacia, and ADVIA Centaur immunoassay system, Bayer Diagnostics) and the test results were correlated with the clinical data.

RESULTS

Statistical analysis revealed no significant difference between the two in vitro tests compared with clinical history. The sensitivities and specificities are similar, but the UniCAP system method has higher sensitivity. In the children with cow's milk allergy, the UniCAP system has sensitivity of 91% and specificity of 70%; the ADVIA Centaur immunoassay has sensitivity of 82% and specificity of 74%. In hen's egg allergy, UniCAP system has 94% sensitivity and 64% specificity, and the ADVIA Centaur system has 88% sensitivity and 52% specificity. In inhalant allergies, the two methods show statistically similar performances for both grass pollen allergies (UniCAP sensitivity 100%, specificity 73%; ADVIA Centaur sensitivity 95%, specificity 79%) and in the dust mites allergies (UniCAP sensitivity 91%, specificity 62%; ADVIA Centaur sensitivity 86%, specificity 64%). In cat allergies, the systems showed equivalent results (UniCAP sensitivity 100%, specificity 71%; ADVIA Centaur sensitivity 100%, specificity 70%). Using the UniCAP system, the geometric mean of sIgE values in children with clinical allergy is significantly higher than in sensitized ones. The ADVIA Centaur system shows a similar trend with the exclusion of cow's milk and Dermatophagoides farinae allergens. With this last method the mean value of sIgE is higher in sensitized than in symptomatic children.

CONCLUSION

The new ADVIA Centaur method compares favorably with the results obtained on the UniCAP system. If other studies continue to confirm this data, then the advantages are numerous: the use of only a small quantity of serum (25 micro l per allergen), rapid turnaround time, minimal hands-on time, and no interference from IgG.

High incidence of adverse reactions to egg challenge on first known exposure in young atopic dermatitis children: predictive value of skin prick test and radioallergosorbent test to egg proteins

BACKGROUND

Egg skin prick test (SPT) and/or radioallergosorbent test (RAST) positivity has been described in infants and children with a food allergy, or in infants at high risk of atopy who have never eaten eggs. Clinical reactions are also observed when some of these children or infants eat eggs for the first time.

OBJECTIVE AND METHOD

A prospective study was made of 107 atopic dermatitis (AD) children (66 boys, 41 girls) aged 1-19 months (median 5 months) who had never ingested egg, to compare the outcome of a first oral egg challenge and the results of albumen and yolk SPTs and RASTs.

RESULTS

The egg challenge (conducted at age 12-24 months: mean 16 months, median 15 months) was positive in 72/107 children (67.3%). The reactions were immediate or early (first 6 h) in 56/72 (77.8%). The most severe (all within the first 6 h) were one case of anaphylactic shock (1.4%), three cases of laryngeal oedema (4.1%) and one serious attack of asthma (1.4%). The skin weal diameter at and above which reactions always occurred was 5 mm for both albumen and yolk. They were, however, also observed in the complete absence of a weal. The outcome of the challenge was always positive when the specific IgEs (sIgE) for albumen and yolk were > 99 KU/L and > or = 17.5 KU/L, respectively. Here, too, reactions were noted even when sIgE levels were < 0.35 KU/L.

CONCLUSION

AD children who have never eaten eggs may be sensitized and display reactions at the first ingestion. The percentage of reactions in this series was by no means negligible. These findings were observed in children with mild as well as moderate-severe AD when first examined. SPT for albumen and yolk diameter > or = 5 mm, and sIgE for albumen > 99 KU/L and for yolk > or = 17.5 KU/L were 100% specific in predicting the outcome of the challenge. It may thus be concluded that children with AD whose SPT and/or RAST for albumen and/or yolk are equal to or higher than these cut-off values should not be subjected to the oral challenge when consideration is given to the introduction of egg in their diet. Even when these cut-offs are not reached, however, clinical reactions to the challenge cannot be ruled out a priori, and it should be preferably performed in a protected environment, such as a hospital.

Can we determine a threshold level for allergenic foods by statistical analysis of published data in the literature?

BACKGROUND

The aim of this paper was to investigate whether a statistical model could be developed to estimate a "threshold" dose for foods eliciting allergic reactions in susceptible patients. The threshold dose is defined to be one that elicits allergic reactions in a given (small) proportion of susceptible patients, using data from published studies.

METHODS

Based on data available from the literature, we developed a statistical model using the actual allergen content in the four foods, where data for allergen content are available (peanut, soy, egg, milk).

RESULTS

The model demonstrated that the threshold doses giving a reaction of one in a million in susceptible patients were within the same order of magnitude for egg, milk and soy, but were an order of magnitude lower for peanut flour: 0.005 mg of cow's milk, 0.002 mg of fresh hen's egg, 0.0007 mg of peanut, or 0.0013 mg of soy flour.

CONCLUSIONS

Although several assumptions were made in creating this statistical model, we demonstrated that the previously published differences in threshold doses for various foods can be largely eliminated by comparing actual allergen content; this may therefore serve as a model for further studies.

The correlation between ovomucoid-derived peptides, human leucocyte antigen class II molecules and T cell receptor-complementarity determining region 3 compositions in patients with egg-white allergy

BACKGROUND

Food allergies are more prevalent in children, due to the immature gastrointestinal epithelial membrane barrier allowing more proteins through the barrier and into circulation. Ovomucoid (OM) is one of the major allergens that is found in egg white.

OBJECTIVE

The aim of this study was to determine T cell epitopes, antigen-presenting human leucocyte antigen (HLA) class II molecules of the T cell lines (TCLs) and T cell clones (TCCs), and complementarity determining region (CDR) 3 loops of the T cell receptor (TCR) alpha and beta chains of the TCCs specific to OM.

METHODS

We established TCLs and TCCs specific to OM from peripheral blood mononuclear cells (PBMCs) of four atopic patients with egg-white allergy using a mixture of a panel of overlapping synthetic peptides corresponding to the amino acid sequence of the entire OM. We identified the T cell epitopes by antigen-induced proliferative responses, antigen-presenting molecules using allogeneic PBMCs and CDR3 loops of the TCR alpha and beta chains by cloning and sequence analysis.

RESULTS

The TCLs and TCCs responded to seven different peptides, and their antigen-presenting molecules were different from each other. Sequence analysis of the TCR alpha and beta gene usage of the TCCs showed marked heterogeneity, and the usage of the CDR3 loop of the TCCs involved heterogenous amino acid residues. Interestingly, TCCs 'IH3.3' and 'YT6.1' recognized the same OM peptides, and had the same TCR Vbeta-Jbeta gene usage. Considering that peptide motifs bind to HLA class II molecules, the electrically charged residue (positive or negative) on the CDR3alpha and the CDR3beta loops of TCR of TCC may form ionic bonds with a charged residue on the HLA class II molecules-peptide complex.

CONCLUSIONS

TCCs that have the same TCR gene usage were established from patients who had shown similar hypersensitivity-type, indicating that antigen recognition by a specific TCR is closely associated with the characteristics of each patient's symptoms.

Role of endothelin-converting enzyme, chymase and neutral endopeptidase in the processing of big ET-1, ET-1(1-21) and ET-1(1-31) in the trachea of allergic mice

The present study examined the roles of endothelin-converting enzyme (ECE), neutral endopeptidase (NEP) and mast cell chymase as processors of the endothelin (ET) analogues ET-1(1-21), ET-1(1-31) and big ET-1 in the trachea of allergic mice. Male CBA/CaH mice were sensitized with ovalbumin (10 microg) delivered intraperitoneal on days 1 and 14, and exposed to aerosolized ovalbumin on days 14, 25, 26 and 27 (OVA mice). Mice were killed and the trachea excised for histological analysis and contraction studies on day 28. Tracheae from OVA mice had 40% more mast cells than vehicle-sensitized mice (sham mice). Ovalbumin (10 microg/ml) induced transient contractions (15+/-3% of the C(max)) in tracheae from OVA mice. The ECE inhibitor CGS35066 (10 microM) inhibited contractions induced by big ET-1 (4.8-fold rightward shift of dose-response curve; P<0.05), but not those induced by either ET-1(1-21) or ET-1(1-31). The chymase inhibitors chymostatin (10 microM) and Bowman-Birk inhibitor (10 microM) had no effect on contractions induced by any of the ET analogues used. The NEP inhibitor CGS24592 (10 microM) inhibited contractions induced by ET-1(1-31) (6.2-fold rightward shift; P<0.05) but not ET-1(1-21) or big ET-1. These data suggest that big ET-1 is processed predominantly by a CGS35066-sensitive ECE within allergic airways rather than by mast cell-derived proteases such as chymase. If endogenous ET-1(1-31) is formed within allergic airways, it is likely to undergo further conversion by NEP to more active products.

Prediction of tolerance on the basis of quantification of egg white-specific IgE antibodies in children with egg allergy

BACKGROUND

It is thought that the natural evolution of food allergy has a good tolerance prognosis. However, there are few follow-up studies that determine the exact probability of tolerance to a given food or that analyze prognostic factors that can help us to understand the evolution of a child who begins life with a food allergy.

OBJECTIVE

We sought to determine the likelihood that children younger than 2 years of age with allergy to egg would eventually have tolerance to it and to analyze several prognostic predictors using egg white-specific IgE level as the main variable.

METHODS

We performed a prospective study of 58 children younger than 2 years of age with egg allergy, who were studied periodically until tolerance developed or until the end of the study. During the follow-up period, open challenge tests were carried out according to previously established criteria to verify tolerance to egg. Factors such as egg white-specific IgE level, serum total IgE level, symptoms after egg ingestion, size of skin prick test reactions to egg white, atopic dermatitis, and sex were analyzed as prognostic markers. Kaplan-Meier survival curves were used to calculate cumulative tolerance probability. Predictor influence and relative prognostic importance were estimated with the Cox proportional regression model.

RESULTS

The median time from the appearance of the first symptoms to tolerance was 35 months. Cumulative tolerance probability was 16% at 12 months of follow-up, 28% at 24 months, 52% at 36 months, 57% at 48 months, and 66% at 60 months. The relative weight of prognostic factors, expressed as the hazard ratio, was 50.95 for symptoms and 3.74 for the size of skin prick test reactions, with both being independent effects. The hazard ratio was 1.173 for every 0.1-unit decrease in the concentration log (decimal logarithm) of specific IgE level, with this effect being associated with tolerance only in children with cutaneous symptoms.

CONCLUSIONS

Half of the children younger than 2 years of age with egg allergy will tolerate the food at 35 months of follow-up, and the proportion could be 66% after 5 years. At that age, the main predictors were the symptoms experienced after egg ingestion, followed by the size of skin prick test reactions. In addition, the specific IgE antibody level is an important prognostic marker in children who only had cutaneous symptoms.

[Immediate adverse reactions after administration of the influenza vaccine to patients with positive CAP-RAST to egg white]

We investigated the safety of administration of influenza vaccine to patients with positive CAP-RAST to egg white. The content of OVA in the influenza vaccine preparations was measured by Sandwich ELISA. The concentration of OVA in the vaccine preparations ranged from 2 to 8 ng/ml. We administered influenza vaccine to 36 high risk patients who had positive CAP-RAST (> 4 score) to egg white and/or had experienced immediate type hypersensitivity after ingestion of egg. One out of them showed local swelling. All the rest of the patients received influenza vaccine without any serious systemic adverse reactions. We also investigated the incidence of immediate adverse reactions after vaccination in the group of 104 patients with positive CAP-RAST to egg white compared to the group of 98 patients with negative CAP-RAST. No significant difference was found in the incidence of adverse reaction between the two groups (group of positive CAP-RAST to egg white: 0.5%, negative group: 2.2%). These results demonstrate that most of the patients with positive CAP-RAST to egg white, even those with allergic reactions after egg ingestion, can safely receive an influenza vaccine.

Specific immune response to occupational antigens in asymptomatic egg processing workers

BACKGROUND

Hen's egg proteins are known sensitizers and may cause occupational respiratory diseases in exposed workers. The study was conducted in order to ascertain the prevalence of sensitization to work-related antigens in asymptomatic egg processing factory workers.

METHODS

Clinical history, respiratory function, atopy and the presence of specific antibodies to environmental and occupational antigens were evaluated in 77 workers. A total of 116 unexposed and non-professionally exposed controls were also studied. The antigen concentration of the factory environment was measured.

RESULTS

Specific IgE and precipitin positivity to egg components was more frequently present in workers than in the two control groups. The egg white protein concentration was higher in the egg breaking area.

CONCLUSIONS

The avian proteins inhaled induced immune responses to occupational antigens in asymptomatic, professionally exposed subjects. Measures to decrease environmental antigen concentrations and thorough clinical monitoring of sensitized workers are advocated.

Identification and fine mapping of IgG and IgE epitopes in ovomucoid

Ovomucoid is a major allergen in hen egg white which causes a serious IgE-mediated food allergy reaction. This study determined eight IgG epitopes, 5-11 amino acids in length, and nine IgE epitopes, 5-16 amino acids in length, within the primary sequence in ovomucoid using arrays of overlapping peptides synthesized on cellulose membranes. Pooled sera from eight egg-allergic patients were used to probe the membrane. We also analyzed the amino acids that are critical for antibody binding by substituting a single amino acid within each epitope. Mutational analysis of the epitopes indicated that charged amino acids (aspartic acid, glutamic acid, and lysine) and some hydrophobic (leucine, phenylalanine, and glycine) and polar (serine, threonine, tyrosine, and cystein) amino acids were important for antibody binding. These results provide useful information for the molecular design necessary to reduce the allergenicity of ovomucoid, and a better understanding of structure-function relationships of allergic epitopes in food proteins.

Cellular immune responses to ovalbumin and house dust mite in egg-allergic children

BACKGROUND

Although IgE-mediated food (egg) allergy is typically lost with age the underlying immune mechanisms are not understood, particularly in relation to the development of persistent IgE-mediated aeroallergen sensitivity.

METHODS

Lymphoproliferation and cytokine responses (IL-5, IL-10, IL-13 and IFN-gamma) to house dust mite (HDM) allergen and egg ovalbumin (OVA) were assessed using peripheral blood mononuclear cells (PBMC) from children aged 6 months to 5 years (n = 59) with acute IgE-mediated egg allergy (urticaria and angiedema or anaphylaxis), as confirmed by positive skin prick testing (SPT). Of these 46 had positive SPT on the day of blood collection and 13 had outgrown egg allergy (negative SPT and successful egg challenge). Where possible, responses were compared with previous data from nonallergic children of similar ages (n = 107).

RESULTS

Transient lymphoproliferative responses to OVA were seen in both egg-allergic and nonallergic children, but were more marked and more prolonged in egg-allergic children. Younger egg-allergic children (< 18 months) showed a mixed Th0 cytokine response to OVA, with readily detectable IFN-gamma, IL-5, IL-13 IL-10. Although IL-13 and IL-5 responses (OVA) correlated in younger egg-allergic children, there was a dissociation of these Th2 responses with age. Loss of clinical reactivity to egg was associated with almost complete loss of IL-5 responses and OVA-specific lymphoproliferation. Although IL-13 levels tended to be lower with age, this was not significant. Strong IFN-gamma and IL-10 responses to OVA persisted in older children after loss of OVA-specific lymphoproliferation. Lymphoproliferative responses to HDM also developed earlier in egg-allergic children compared with nonallergic children. Th1 (IFN-gamma) responses to HDM were largely below detection prior to 18 months of age, but increased significantly with age. In egg-allergic children Th2 (IL-5, IL-13) HDM responses also progressively increased with age. At 3 years of age almost all egg-allergic children had positive SPT to HDM and positive lymphoproliferative responses to HDM, with strong Th1 and Th2 (Th0) cytokine production.

CONCLUSIONS

IL-5 responses (rather than IL-13) responses most closely reflected clinical food allergy, with dissociation of IL-5 and IL-13 responses in older and egg-tolerant children. In this population, food and aeroallergen sensitivity was not associated with inability to produce IFN-gamma, but rather with mixed Th2 and Th1 (Th0) responses. Strong IL-10 and IFN-gamma responses where associated with the development of tolerance, suggesting persistent 'regulatory' populations of OVA-specific T cells, rather than clonal deletion of OVA responsive T-cells.

Low-protein diet induces oral tolerance to ovalbumin in mice

The suitable development of oral tolerance against ingested dietary foods is of critical importance to escaping food allergy. Using mice as an animal model for oral tolerance against ovalbumin (OVA) as a dietary antigen, we investigated the effects of dietary protein on their immunological tolerance. Female BALB/c mice fed either a 20% or 5% protein diet were orally administered 5 mg of OVA for four consecutive days, then immunized intraperitoneally with 100 microg of OVA. The immunized group of mice were fed and treated in the same manner, except that they received orally distilled water for four consecutive days before receiving intraperitoneal immunization with the antigen. Immunization alone with OVA elevated the total IgE and induced the production of OVA-specific antibodies IgE, IgG, IgG1, and IgG2a in the sera of both the 20% and 5% protein diet groups. The oral administration of OVA to mice before intraperitoneal immunization significantly reduced the total IgE and OVA-specific antibodies in mice fed 5% protein diet, but it had hardly any effect on those in mice fed a 20% protein diet. When spleen cells from these groups of mice were cultured with OVA as a mitogen, they responded substantially to OVA in the immunized groups fed 20% and 5% protein diets and in the presensitized group fed 20% protein, but those from the presensitized group fed a 5% protein diet did not respond. Furthermore, when IL-4 was assayed in the spleen cell cultures of the 20% and 5% groups, mice in the presensitized group fed a 5% protein diet produced a significantly less amount of IL-4 than those fed a 20% protein diet. Moreover, irrelevant to the protein amount in the diet, the production of IFN-gamma from spleen cell cultures dramatically decreased in the group without presensitization and profoundly increased in the presensitized group of mice fed a 5% protein diet. These findings suggest that a low-protein diet leads to an induction of oral tolerance against dietary antigens; this appears to involve a clear down-regulation of Th2 cytokine, IL-4.