Cord blood IgE against milk and egg antigens

The atopic march: current insights into skin barrier dysfunction and epithelial cell-derived cytokines

Atopic dermatitis often precedes the development of other atopic diseases. The atopic march describes this temporal relationship in the natural history of atopic diseases. Although the pathophysiological mechanisms that underlie this relationship are poorly understood, epidemiological and genetic data have suggested that the skin might be an important route of sensitization to allergens. Animal models have begun to elucidate how skin barrier defects can lead to systemic allergen sensitization. Emerging data now suggest that epithelial cell-derived cytokines such as thymic stromal lymphopoietin (TSLP), IL-33, and IL-25 may drive the progression from atopic dermatitis to asthma and food allergy. This review focuses on current concepts of the role of skin barrier defects and epithelial cell-derived cytokines in the initiation and maintenance of allergic inflammation and the atopic march.

Detection of major food allergens in amniotic fluid: initial allergenic encounter during pregnancy

BACKGROUND

Ingestion of food allergens present in maternal milk during breastfeeding has been hypothesized as a gateway to sensitization to food; however, this process could develop during pregnancy, as the maternal-fetal interface develops a Th2- and Treg-mediated environment to protect the fetus. We hypothesized that in these surroundings, unborn children are exposed to food allergens contained in the mother's diet, possibly giving rise to first sensitization.

METHODS

The presence of allergens in utero was studied by analyzing amniotic fluid (AF) samples in two different stages of pregnancy: at 15-20 weeks and after delivery at term. An antibody microarray was developed to test for the most common food allergens. The array detects the presence of ten allergens from milk, fruit, egg, fish, nuts, and wheat.

RESULTS

AF from 20 pregnant women was collected: eight after delivery at term and 12 from women who underwent diagnostic amniocentesis between weeks 15 and 20 of gestation. The presence of allergens was detected in all samples. Samples from amniocentesis had a higher allergen concentration than samples after delivery at term.

CONCLUSIONS

We demonstrated the presence of intact major food allergens in AF samples. This early contact could explain subsequent sensitization to foods never eaten before.

Prenatal latex sensitization in patients with spina bifida: a pilot study

OBJECT

Patients with spina bifida are particularly vulnerable to developing immunoglobulin E (IgE)-mediated latex sensitization. Even though many risk factors leading to latex allergy in these patients have been described, it is still unclear whether the increased prevalence of latex sensitization is disease associated or due to the procedures used to treat spina bifida. The aim of this study was to assess prenatal latex sensitization in patients with spina bifida by examining IgE levels in umbilical cord blood.

METHODS

Patients with spina bifida and matched healthy infants were recruited from the University Medical Center Hamburg-Eppendorf and Children's Hospital Altona. Latex-specific and total IgE were assessed in umbilical cord blood using ImmunoCAP testing to evaluate the degree of prenatal latex sensitization.

RESULTS

Twenty-two subjects, 10 with spina bifida and 12 healthy individuals, were included. Subjects were selected after matching for sex, gestational age, weight, parental allergy profile, number of prenatal examinations, and utilization of latex tools during pregnancy (propensity score estimates, p = 0.36). In patients with spina bifida, latex-specific and total IgE levels were significantly higher than those in healthy individuals (p = 0.001). After normalization to total IgE, latex-specific IgE levels were higher, yet not significantly increased (p = 0.085).

CONCLUSIONS

Perinatally, there is a significant augmentation of total and latex-specific IgE in patients with spina bifida. After correcting for total IgE, latex-specific IgE was increased, yet not significantly higher than in matched, healthy controls. This pilot study gives novel insights in the immunological reactions related to spina bifida. The increased latex-specific IgE levels could possibly be associated with the occurrence of a latex allergy in the future.

Fetal programming: Early-life modulations that affect adult outcomes

Asthma is a common disease, and the number of people diagnosed with it increases every year. Although genetic background and environmental exposures play major roles in the development of asthma, one cannot overlook the developmental origin of adult disease or fetal programming theory. This review examines the social, genetic, and environmental factors that are associated with fetal programming of asthma. We also present recent studies from our laboratory that strengthen these observations. It is our hope that the reader will come away with a current view of fetal programming in asthma.

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

INTRODUCTION

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

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Prediction of atopy in the first year of life using cord blood IgE levels and family history

We assessed correlations of total and specific cord-blood IgE (cIgE) levels with allergic symptoms in the first year of life. cIgE levels were determined by an immunoassay test in full-term neonates. This is a prospective study in which a questionnaire was used after birth, and at 6 and 12 months of age. We used multiple logistic regression models to assess the association between the family history of atopy and the incidence of allergy. The infants were divided in to groups based on the cIgE level (Group 1 < 0.1 IU/ml, n = 65; Group 2 0.1-0.5 IU/ml, n = 63; Group 3 > 0.5 IU/ml, n = 45). We found the symptoms of atopy in 26 children in Group 1 (40%), 30 (47.6%) in Group 2, and 17 (37.7%) in Group 3; the percentage of atopic diseases was in significantly different among the three groups. No association between a high total cIgE and specific cIgE with atopy family history and the outcome of atopic diseases was discovered. We conclude that neither total nor specific cIgE level with atopy family history can be used as an indicator to single out high risk infants.

Total and antigen-specific IGE levels in umbilical cord blood

The present study was conducted to learn whether the perinatal and environmental factors could influence the total and antigen-specific IgE levels in umbilical cord blood. Retrospective data were obtained from 173 mother-infant pairs. Total and specific (for children's food, wheat/grass and house dust mite-HDM) cord blood IgE levels were determined using the immunoassay test. The total cord blood IgE was between 0.0-23.08 IU/ml (mean 0.55 ± 2.07 IU/ml; median 0.16 IU/ml). Total IgE levels were significantly higher in boys compared with girls (OR = 2.2; P = 0.007), and in newborns with complicated pregnancy (OR = 2.7; P = 0.003). A greater number of siblings correlated with increases in the total cord blood IgE (P < 0.02). We detected specific IgE in 34 newborns (40 positive tests). A long-standing contact with a cat during pregnancy decreased the specific IgE level for wheat/grass (OR = 3.2; P < 0.07) and for children's food (OR = 5.0; P < 0.04), and the contact with a dog decreased the specific-IgE for wheat/grass (OR = 0.3; P < 0.05). Exposure to tobacco smoke correlated with the positive specific IgE toward house dust mite (OR = 4.7; P = 0.005).

Recent advances in the understanding of egg allergens: basic, industrial, and clinical perspectives

The emergence of egg allergy has had both industrial and clinical implications. In industrialized countries, egg allergy accounts for one of the most prevalent food hypersensitivities, especially in children. Atopic dermatitis represents the most common clinical manifestation in infancy; however, the range of clinical signs is broad and encompasses life-threatening anaphylaxis. The dominant egg allergens are proteins and are mainly present in the egg white, for example, ovalbumin, ovomucoid, ovotransferrin, and lysozyme. However, egg yolk also displays low-level allergenicity, for example, alpha-livetin. Strict avoidance of the offending food remains the most common recommendation for egg-allergic individuals. Nevertheless, the omnipresence of egg-derived components in prepackaged or prepared foods makes it difficult. Therefore, more efficient preventive approaches are investigated to protect consumers from inadvertent exposure and ensuing adverse reactions. On the one hand, commercial kits have become readily available that allow for the detection of egg contaminants at trace levels. On the other hand, attempts to produce hypoallergenic egg-containing products through food-processing techniques have met with promising results, but the approach is limited due to its potentially undesirable effects on the unique functional and sensory attributes of egg proteins. Therefore, the development of preventive or curative strategies for egg allergy remains strongly warranted. Pilot studies have suggested that oral immunotherapy (IT) with raw or cooked preparations of egg may represent a safe alternative, immediately available to allergic subjects, but remains applicable to only nonanaphylactic patients. Due to the limitations of conventional IT, novel forms of immunotherapy are sought based on information obtained from the molecular characterization of major egg allergens. In the past decade, promising approaches to the treatment and prevention of egg allergy have been explored and include, among others, the production of hypoallergenic recombinant egg proteins, the development of customized peptides, and bacterial-mediated immunotherapy. Nonspecific approaches have also been evaluated, and preliminary trials with the use of probiotic bacteria have yielded encouraging results. The current understanding of egg allergens offers novel approaches toward the making of food products safe for human consumption and the development of efficient immunotherapeutic strategies.

Relationship between maternal- and fetal-specific IgE

AIM

A positive correlation between maternal and cord-blood IgE levels is well documented for total IgEs, but not for specific IgEs. The difficulty in detecting specific cord-blood IgEs is due to their low concentrations, which hinder their dosage by low-sensitivity methods. The study aimed to correlate maternal and foetal specific IgEs against individual cow's milk proteins, detected by highly sensitive and specific techniques.

METHODS

Cow's milk specific IgE detection was performed by chemiluminescence on 52 specimens of maternal and cord blood after cow's milk protein separation by 1D and 2D gel electrophoresis. Cow's milk protein (CMP) antigens were identified by mass spectrometry techniques.

RESULTS

Specific IgEs for CMPs were found in 25/52 (48.1%) of maternal sera and in 19/52 (37%) of cord-blood sera. In order of decreasing frequency, the proteins found were BSA, IgG heavy chain, caseins and, in a single case, b-lactoglobulin. Positive cord-blood sera in all cases corresponded to a positive maternal result, and maternal and foetal immunoreactivity patterns were closely correlated. Moreover, in no case was there a positive cord-blood response with a negative maternal response.

CONCLUSION

The study demonstrates a close relationship between maternal and cord-blood specific IgE patterns. The phenomenon observed could provide a model to elucidate the general production method of foetal IgEs, which might only be produced in the presence of both the corresponding maternal IgE and the related allergen.

Phenotype definition, age, and gender in the genetics of asthma and atopy

When studying genetics of complex diseases it is important to have a clearly described and objective phenotype. When drawing conclusions in association studies, age and gender of the population should be considered. Until we know what causes phenotypic differences between males and females and between children and adults, we should try to study longitudinal cohorts with phenotype assessment at different time points and stratify our analyses for gender. To acquire sufficient power for these types of analyses, international collaboration may be the only way to elucidate the intricate, gene-environmental interactions in atopy and asthma in an age- and gender-dependent manor.

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.

Expression of CD21 and CD23 during human fetal development

Neonates produce lower levels of IgE compared with adults. Diminished IL-4 production and impaired up-regulation of CD40L by neonatal T cells could explain this, however other regulators of IgE production, such as CD21 and CD23, could contribute to reduced circulating IgE levels during fetal development. Heparinized blood samples were collected from adults and from the umbilical cord at premature and term births. Whole blood flow cytometry was used to assess the percentage of T (CD3(+)) and B (CD19(+)) lymphocytes expressing CD21 and/or CD23 at 26-29 (n = 3), 30-33 (n = 7), 34-37 (n = 5), and >37 (n = 11) wk of gestation, as well as in adults (n = 15). Plasma-soluble CD21 was also measured. At term, the percentage of CD21(+) and CD23(+) B cells was comparable to the adult, however, the percentage of cells positive for each of these surface antigens was decreased significantly before term. The percentage of T cells expressing CD21 from all gestations was significantly higher than the adult and the percentage positive decreased with increasing gestational age. Conversely, soluble CD21 levels increased with increasing gestation to be comparable to the adult by term. Thus, it is unlikely that altered expression of CD21 and CD23 on B cells contributes to the low level of IgE in the neonatal circulation unless functional differences occur or a lack of processing to the soluble form is important in regulating IgE production. However the abundance of CD21-positive T cells could alter the T- and B-cell interaction necessary for IgE switching by B cells and, thereby, especially with impaired IL-4 production, limit IgE production.

The pattern of atopic sensitization is associated with the development of asthma in childhood

BACKGROUND

Even though atopic sensitization has been shown to be strongly associated with childhood asthma, asthma eventually develops in only one third of atopic children.

OBJECTIVE

The aim of this study was to prospectively investigate the pattern of atopic sensitization typically associated with the development of asthma in childhood.

METHODS

The German Multicenter Allergy Study followed 1314 children from birth to the age of 7 years. Parental questionnaires on asthma and asthmatic symptoms were completed 6 times up to the age of 2 years and from then on yearly. Determination of specific IgE to 9 food and inhalant allergens was performed yearly, and at the age of 7 years, a bronchial histamine challenge was conducted.

RESULTS

Onset of atopic sensitization in atopic children with current asthma at the age of 7 years was significantly earlier than in atopic children without current asthma (39.4% before age 1 year vs 21.0%, P =.015). Early atopic sensitization without any sensitization to inhalant allergens at the age of 7 years conferred no increased risk for asthma at this age. Only those children sensitized to any allergen early in life and sensitized to inhalant allergens by the age of 7 years were at a significantly increased risk of being asthmatic at this age (odds ratio, 10.12; 95% CI, 3.81-26.88). However, even in this group of persistently sensitized children, the risk of being asthmatic at the age of 7 years was only increased if a positive parental history of asthma or atopy was present (odds ratio, 15.56; 95% CI, 5.78-41.83), with the effect being strongest for maternal asthma.

CONCLUSION

Our results indicate that an underlying factor pertaining to asthma and maternal transmission may determine both a certain pattern of sensitization and the expression of asthma.

Maternal programming in asthma and allergy

There has been increasing interest in the possibility that the mother has an important role to play in influencing the development of fetal and infant immune responses to allergens during gestation. This finding, by several groups, of specific immune responses of infants at birth to individual trigger factors associated with an underlying immaturity of cytokine production, is intriguing in the light of the development of subsequent allergic disease. The interactions between mother, placenta and fetus are now forming a focus for ongoing research and may be a potential target for intervention aimed at preventing allergic asthma.