Sensitization to hen's egg at the age of twelve months is predictive for allergic sensitization to common indoor and outdoor allergens at the age of three years

Egg allergy in infancy predicts respiratory allergic disease by 4 years of age

Sensitization to hen's egg early in life has been proposed as a predictor for respiratory allergic disease during childhood. However, symptomatic egg allergy in infancy has not been studied in this context. In 1989, a cohort of consecutive births was recruited. Data on family history of atopy and environmental factors were collected. At 4 years of age, 1,218 children were seen of whom 981 were skin-prick tested with a range of food and aero-allergens. Of the 1,218 children, 29 (2.4%) had suffered symptomatic egg allergy (20 during infancy). Egg allergy in infancy was associated with increased respiratory (asthma, rhinitis) allergic disease (odds ratio [OR] 5.0, 95% confidence intervals [CI] 1.1-22.3; p < 0.05) at 4 years of age, with a positive predictive value (PPV) of 55.0%. The addition of infantile eczema to egg allergy increased the PPV to 80% whereas the addition of family history of atopy had no effect. Egg allergy also increased aero-allergen sensitization (OR 6.1, CI 1.1-37.5; PPV 61.1%; p < 0.05). As a predictor for respiratory allergic disease and aeroallergen sensitization, it carried a high specificity but poor sensitivity. Hence, egg allergy in infancy, especially when coexisting with eczema, increases respiratory allergic symptoms and aero-allergen sensitization in early childhood.

Effect of house dust mite avoidance measures in children with atopic dermatitis

BACKGROUND

House dust mite allergens are associated with atopic dermatitis (AD).

OBJECTIVES

The aim of our study was to verify if house dust mite allergen avoidance measures can improve the clinical manifestations of AD in children.

METHODS

Forty-one children (mean age 3.9 years) affected by AD associated with high total and/or specific IgE serum levels ('extrinsic' AD) were recruited. Clinical evaluation was performed utilizing the Severity Scoring of AD (SCORAD) index; dust was sampled from the children's beds and tested using an enzyme-linked immunosorbent assay. The study was planned in two parts. In the first part, a placebo-controlled trial of 2 months duration, mite allergen avoidance measures (encasing mattresses and pillows; a weekly hot wash of bedding; frequent vacuum cleaning of living room and bedroom; soft toys and carpets regularly cleaned or removed; no pets allowed) were recommended to group A patients, but not to group B. In the second part of the study, environmental avoidance measures were recommended to initial control group B patients also. One year after the start of the study the amounts of mite allergen in the home and clinical score of AD were measured in both groups.

RESULTS

At the end of the first part of the study, significant decreases in major allergens of Dermatophagoides pteronyssinus (Der p1) and D. farinae (Der f1) load (from 393 to 94 ng m-2) and concentration (from 1.84 to 0.73 microg g-1 of dust) in children's beds were observed in treatment group A. At the same time, in this group the mean SCORAD index improved significantly (from 33 to 26; P = 0.022). After 12 months, when all patients had used allergen avoidance measures, Der p1 + Der f1 load, concentration and clinical score had improved, reaching similar values in both groups.

CONCLUSIONS

Simple mite allergen avoidance measures should be recommended to families with children affected by extrinsic AD in order to control the clinical manifestations and prevent mite sensitization.

Markers for early sensitization and inflammation in relation to clinical manifestations of atopic disease up to 2 years of age in 133 high-risk children

BACKGROUND

The combination of genetic susceptibility and environmental factors induce allergic sensitization and subsequently local inflammation, resulting in atopic manifestations.

OBJECTIVE

To examine whether immunological features reflecting sensitization (total and specific IgE levels, allergen-induced proliferative responses and skin tests) and markers of inflammation (plasma sE-selectin and blood eosinophils) are related to the clinical expression of atopy and whether they precede atopic disease in children up to 2 years of age.

METHODS

The development of these markers during the first 2 years of life was studied prospectively in 133 newborns at high risk to develop atopic disease.

RESULTS

The prevalence of atopic disease increased from 25% at 12 months to 32% at 24 months of age. The children with food allergy at 12 months, who all had atopic dermatitis (AD), turned out to have asthma-like disease in 40% and AD in 100% at the age of 24 months. Total IgE levels increased with time and from 12 months onward levels started to differ markedly between atopics and nonatopics. Food-specific IgE antibodies were significantly associated with AD (relative risk [RR] = 2.39), food (RR = 1.32) and upper-airway allergy (RR = 1.20), and house dust mite-specific IgE antibodies with upper-airway allergy (RR = 5.00). A positive skin test was significantly associated with AD (RR = 2.90) and food allergy (RR = 1.36). The inflammation markers investigated, were not related to the clinical expression or preceded atopic disease at 2 years of age in high-risk children.

CONCLUSION

Positive skin tests and specific IgE to food or inhalant allergens were related to the clinical expression of different atopic diseases. The combination of AD and food allergy at 12 months reflected the strongest risk factor in this high risk cohort for the development of asthma-like disease at 24 months of age.

The natural history of sensitizations to food and aeroallergens in atopic dermatitis: a 4-year follow-Up

The natural history of atopic dermatitis (AD) is variable. Generally the dermatitis disappears during the first years of life, but it is often followed by the appearance of allergic respiratory diseases (ARDs). Our aim was to establish the risk factors for developing an ARD in children with AD. We followed up for 4 years 78 children (51 boys, 27 girls) with mild (26%), moderate (48%), and severe (26%) AD (clinical score proposed by Rajka and Langeland). In all the patients IgE serum levels were checked and skin prick tests (SPTs) were performed at the first examination. The SPTs were repeated in 68 children at the end of the study. The children with severe AD had significantly higher IgE serum levels than those with mild or moderate AD. SPTs at the first observation were positive in 47% of cases, mostly in patients with severe AD, with a prevalence of food allergens, particularly in younger patients. At the second observation, SPTs were positive in 65% of cases, including 100% of children with severe AD. Inhalants were the most common allergens. An ARD appeared in 38% of all patients: in 75% of those with severe AD and in 54% of those with a positive first SPT. Allergic screening should be carried out at an early age, especially in severe AD, since SPT positivity to food allergens, associated with severe clinical AD symptoms and a high IgE serum level, identifies those children ages 0-3 years at high risk of development of ARD.

Quantitative IgE antibody assays in allergic diseases

During the past several years, immunoassays for specific IgE antibodies have been refined to permit reporting results in mass units. Thus quantitative immunoassays for IgE antibodies may be an adjunct to skin tests. In cases of food allergy among children with atopic dermatitis, cutoff values for IgE antibody concentrations to egg, milk, peanut, and fish have been derived to provide 95% positive and 90% negative predictive values. Food-specific IgE antibody determinations can also be used to predict which food allergies are resolving spontaneously. Elevated egg-specific IgE antibody levels in infancy are associated with significantly increased risk for development of inhalant allergies later in childhood. In cases of inhalant allergy, specific IgE antibody levels correlate closely with results of inhalation challenge studies in cat-sensitive persons. Also, mite-specific IgE antibody levels correlate significantly with the mite allergen contents of reservoir dust in the homes of mite-sensitive persons. Immunoassays for quantitation of specific IgE antibodies may be used to document allergen sensitization over time and to evaluate the risk of reaction on allergen exposure. However, immunoassays and skin tests are not entirely interchangeable, and neither will replace the other in appropriate circumstances.

Serum IgE response to orally ingested antigen: a novel IgE response model with allergen-specific T-cell receptor transgenic mice

BACKGROUND

The mechanism by which orally ingested allergens elicit an IgE response remains unclear because there are few animal models available for investigation of this response.

OBJECTIVE

We tried to develop a murine model suitable for investigation of the IgE response to orally ingested allergens, which would allow us to identify T cells that could promote IgE production.

METHODS

Ovalbumin (OVA)-specific T-cell receptor transgenic mice were fed a diet containing OVA, and both the serum antibody response and cytokine production by splenocytes were examined.

RESULTS

Oral administration of OVA to transgenic mice led to an increase in the levels of both antigen-specific IgE and total IgE in the sera. Subsequent intravenous challenge of OVA-fed transgenic mice with OVA resulted in anaphylactic shock. Analysis of cytokine production by splenocytes revealed that high IL-4-producing T cells appeared in the spleen 1 week after the start of feeding the OVA diet. T cells from these mice were found to promote IgE secretion by BALB/c B cells in vitro. This helper activity and the levels of IL-4 secretion were diminished after long-term feeding. These findings suggest the possibility that the orally ingested antigen elicited a response by a subpopulation of T cells that produce high levels of T(H2)-type cytokines and that promote IgE secretion, and these same T cells were tolerized by the orally ingested antigen.

CONCLUSION

This experimental model with transgenic mice may be a useful tool for further studies of the cellular and molecular mechanisms of the T-cell and IgE responses to orally ingested antigens.

Associations between duration of breast-feeding, sensitization to hens' eggs and eczema infantum in one and two year old children at high risk of atopy

Through a cohort study, factors for the development of atopic disorders among children at high-risk of atopy were investigated by means of anamnesis, lifestyle factors and laboratory parameters. 475 high-risk children were selected out of the whole population of infants born within one year in the City and District of Leipzig. These 475 had an increased cord blood IgE (> 0.9 kU7l), double positive atopic family history (parents/siblings) or low birthweight (1500-2500 g). Questionnaires are answered regularly by the parents and the children are clinically examined annually.

RESULTS

In the first and second year of life there has been a statistically significant correlation (p < 0.0001) between increased cord blood IgE and increased total IgE. At the age of one year we found eczema infantum in 51 out of 323 high-risk children. There was a significant association (p = 0.0001) between sensitization against hens' eggs and eczema. Infants who had been exclusively breast-fed > or = 5 months were more frequently sensitized to hens' egg and an eczema infantum was to diagnose more frequently. Significant differences in this respect were found within the risk groups, depending on family history of atopy and cord blood IgE. The duration of breast-feeding showed no correlation with sensitization to hens' eggs or atopy in two-year-olds.

Food allergy. Part 1: immunopathogenesis and clinical disorders

Up to 8% of children less than 3 years of age and approximately 2% of the adult population experience food-induced allergic disorders. A limited number of foods are responsible for the vast majority of food-induced allergic reactions: milk, egg, peanuts, fish, and tree nuts in children and peanuts, tree nuts, fish, and shellfish in adults. Food-induced allergic reactions are responsible for a variety of symptoms involving the skin, gastrointestinal tract, and respiratory tract and may be caused by IgE-mediated and non-IgE-mediated mechanisms. In part 1 of this series, immunopathogenic mechanisms and clinical disorders of food allergy are described.

Relation between IgG antibodies to foods and IgE antibodies to milk, egg, cat, dog and/or mite in a cross-sectional study

BACKGROUND

Because IgG antibodies to foods can be detected before IgE antibodies to inhalants, increased levels of IgG antibodies to foods might be used as a predictor of IgE-mediated allergy in initially nonatopic children.

OBJECTIVE

To examine the cross-sectional relation between IgG to foods (i.e. mixture of wheat and rice, mixture of soybean and peanut, egg white, cow's milk, meat, orange and potato) and specific IgE to cat, dog, mite, milk and egg white in 1-year-old children.

METHODS

All atopic children (n = 120; 58 with and 62 without eczema) and a random sample of the nonatopic children (n = 144) of the Bokaal study were tested on their IgG response to foods. The IgG results of the food assays were dichotomized high or low using the 66th centile as a cut-off value.

RESULTS

Atopic children more often had high IgG levels to foods than nonatopic children. IgG to egg white (OR = 7.50) and mixture of wheat and rice (OR = 4.79) were most strongly associated with positive specific IgE. In a stepwise logistic regression analysis egg white, mixture of wheat and rice, and orange were selected (OR = 3.76, OR = 2.43, and OR = 2.11, respectively). In children without eczema higher levels of IgG to foods were still significantly associated with atopy, which was most prominent for egg white, orange and cow's milk.

CONCLUSION

An increased IgG antibody level to foods, especially to egg white, orange, and mixture of wheat and rice, indicates an increased risk of having IgE to cat, dog, mite, egg and/or milk allergens, even in the noneczematous group. Therefore, in another prospective study we are currently investigating the usefulness of IgG in early identification, i.e. before IgE antibodies can be detected, of children with an increased risk of developing allergic diseases in the future.

Is atopic dermatitis predictable?

Atopic dermatitis (AD) is a common skin disease which affects 10 to 20% of the population, usually with onset during infancy. The frequency of AD appears to have increased over the past three decades. Attempts to identify parameters predictive of the development of AD have been made by many investigators during the last decades. Although genetic factors remain unmodifiable, avoidance of relevant trigger factors could modify the development of AD. This paper reviews and discusses findings of the last several years and outlines recent advances in genetic studies of AD. In spite of decades of intensive research and newly developed technology, the parental history of AD appears to be the most valuable predictive parameter. However, the predictive capacity is not sufficient to recommend it as screening instrument. At this time, a perinatal screening with the objective of primary prevention of AD does not seem feasible.

Immune dysregulation as a cause for allergic asthma

Allergic asthma is being increasingly understood as a disease caused by Th2-mediated immune responses to inhaled allergens. Most individuals fail to respond to allergens with a Th2 response, and thus, allergic asthma can be considered the result of an abnormally regulated or dysregulated immune response. The prevalence of asthma has risen precipitously in urbanized cultures, as contrasted with third world countries. This observation underlies the heightened efforts in the past few years of basic and applied research efforts to gain a better understanding of both normal and dysregulated immunity to antigens introduced via the airways. This review focuses on recent human studies into the immune dysregulation that results in the asthma phenotype, but also cites selected relevant papers from research with experimental animals.

Prevalence and severity of food allergy--need for control

Food allergy is an increasingly recognized manifestation of atopy. Patient and public awareness of food allergy is also increasing. Justifiable demands are being made for better medical guidance of the practice of food labelling for industry and catering businesses. Such advice must bear in mind the relative frequency and severity of allergies to certain foods. Some commonly allergenic foods (milk, egg, soya, wheat) are staple components of the diets of populations, used widely in prepared foods. The frequency of the allergies to these foods and their widespread uses means they and their derivatives must be declared on food labels. Less commonly used foods such as fish, shellfish, peanut, and tree nuts demand declaration due to the severity of reactions induced in the admittedly more rare, but increasingly common, sufferers of these allergies. Reactions to more unusual foods are increasingly being identified, and the "minimum" list is likely to be extended in the future.

Environmental allergens and childhood asthma

Exposure to allergens has been shown to lead to sensitization and to the subsequent development of airway hyperresponsiveness in genetically predisposed individuals. Increasing interest is being devoted to mechanisms for the prevention of allergen sensitization and asthma development. Primary prevention (avoiding the sensitization to allergens) requires a large effort as the majority of atopic sensitizations occur in children with no demonstrable risk at the birth. Secondary prevention (deterrence of disease expression despite prior IgE sensitization) requires methods for detecting the population at risk by means of large population screening. Tertiary prevention (minimizing the morbidity for those who already have the disease) may be achieved by allergen avoidance, which has been demonstrated to effectively decrease inflammation in symptomatic patients.

[What is new in pediatric pneumology?]

Have been selected for this review: 1) the recent and impressive development of high-resolution and spiral CT scan in pediatric thoracic imaging; 2) the emerging of new and promising therapies for asthma (long acting inhaled beta 2-agonists, leukotriene antagonists, anti-IgE monoclonal antibodies); 3) the multifactorial origin of asthma in childhood; 4) the development of thoracoscopic surgery, a minimal-invasive approach beneficial in numerous circumstances.

Prediction of sensitization to inhalant allergens in childhood: evaluating family history, atopic dermatitis and sensitization to food allergens. The MAS Study Group. Multicentre Allergy Study

BACKGROUND

A family history of atopy is a poor predictor of sensitization to inhalant allergens and allergic disease during childhood. We recently identified early sensitization to food allergens, especially hen's egg, as a valuable predictor of subsequent sensitization to inhalant allergens.

OBJECTIVE

(1) Whether prediction will be improved by in vitro allergy tests at 1 year of age in combination with family history and medical history data. (2) Comparison with the capacities of in vitro tests to predict sensitization to aeroallergens.

METHODS

Of an observational birth cohort study (MAS) 49 children who were sensitized to inhalant allergens at 5 years of age and 116 non-sensitized controls were included in the present study. For the prediction of sensitization to inhalant allergens the following prognostic factors were evaluated: atopic family history (FH), atopic dermatitis (AD) during the first year of life, two in vitro allergy tests for specific IgE to common food allergens at 1 year of age (fx5 [Pharmacia] and single allergen specific tests (sIgE) for four allergens) and 'high' total serum IgE, defined by three different cut off points.

RESULTS

The combination of medical history data and laboratory tests resulted in the best predictive discrimination. The positive predictive values (PPV) were higher if sensitization to food was detected by single allergen specific tests (PPV: 66%/75%/100% corresponding to the three evaluated risk groups) than by the qualitative fx5 (PPV: 46%/65%/100%). The negative predictive values were equal for both tests (69 and 92% for the two low risk groups). High total serum IgE had low predictive capacity.

CONCLUSION

During infancy the prediction of sensitization to inhalant allergens should be based on medical history data and allergy tests determining sensitization to food allergens. The in vitro tests improve the predictive discrimination, but the individual risk profile of the child must be considered for a reliable and valid prediction.

Atopic dermatitis in early infancy predicts allergic airway disease at 5 years

BACKGROUND

Screening tests for atopy risk in newborns have a low predictive value. If early atopic symptoms and signs could be used as predictors for the next expected atopic disorder then secondary prevention could be employed. The aim of this study was to evaluate the capacity of early atopic dermatitis to predict aeroallergen sensitization and the manifestation of respiratory atopic disorders at 5 years of age.

METHODS

1314 children of a German prospective birth cohort study MAS-90 were followed from birth up to 5 years of age. Atopic dermatitis, asthma and rhinoconjunctivitis were diagnosed from symptoms and signs at physical examinations and by interviews of the parents. Blood was drawn at 1, 2, 3, and 5 years of age. Aeroallergen sensitization was diagnosed by a specific IgE value of at least 0.35 kU/L (CAP class > or = 1) against any of five respiratory allergens (mite, cat, dog, birch, grass).

RESULTS

Atopic dermatitis in the first 3 months was a risk factor for aeroallergen sensitization at 5 years. The risk increased with a positive family history for atopic diseases. Seventy-seven per cent of children with two atopic parents and early atopic dermatitis were sensitized against aeroallergens at 5 years, i.e. could have been predicted in early infancy without any laboratory tests. Although these risk factors were also significantly associated with the manifestation of allergic airway disease, the positive predictive value for this outcome at age 5 years was not yet as high, i.e. 50%.

CONCLUSION

Infants with very early signs of atopic dermatitis and a positive family history are candidates for early intervention measures against respiratory allergies.

Long-lasting sensitization to food during the first two years precedes allergic airway disease. The MAS Study Group, Germany

The purpose of the study was to investigate whether the duration of sensitization to food allergens during early childhood is related to later development of IgE mediated hypersensitivity to inhalant allergens and of allergic rhinitis and asthma in 5-year-old children and whether long-lasting food-sensitization may be used to predict subsequent allergic airway diseases. Five hundred and eight children of a prospective birth cohort study with available serum samples at one and two years of age were included and followed up until five years of age. Specific sensitization to food and inhalant allergens and the occurrence of subsequent allergic airway diseases were determined. Children with a long-lasting sensitization to food allergens (persistently sensitized for more than one year) produced significantly higher total IgE and specific IgE levels than children who were only transiently food-sensitized by two years of age. Children persistently sensitized to food had a 3.4 fold higher risk of developing allergic rhinitis and a 5.5 fold higher risk of developing asthma than infants who were only transiently food sensitized. Persistent food sensitization in combination with a positive atopic family history was a strong predictor for the development of allergic rhinitis and asthma at five years of age. The risks for these children are up to 50%, and 67% respectively. Persistently detectable sensitization to food over more than one year in early childhood is a strong prognostic factor for subsequent allergic airway disease. Persistently food-sensitized children especially in atopic families have to be regarded as a high-risk group and should be considered for preventive measures against respiratory atopy.

The allergy march: from food to pollen

There is epidemiological evidence, especially from longitudinal studies, that clinical manifestations of atopy as well as IgE antibodies against food and aeroallergens show a systematic sequence of events. The atopic march begins with food allergy associated gastrointestinal disorders and atopic dermatitis followed by respiratory allergies, i.e. asthma and atopic rhino-conjunctivitis. Detectable food antibodies, especially against egg and milk proteins, usually precede or accompany the early clinical symptoms and signs. Similarly, aeroallergen sensitization, first against indoor allergen antibodies, succeeded by outdoor allergen antibodies, precede the clinical manifestation of respiratory allergy. Early atopic events, either manifestation or sensitization can be used as risk markers or even predictors of atopic disorders to implement preventive measures. Early atopic dermatitis as well as elevated serum IgE antibodies against food allergens in the first two years of life in combination with a family history can be used as a predictor for aeroallergen sensitization.

Approaches toward the genetic analysis of complex traits: asthma and atopy

With the challenges emerging from the analysis and interpretation of the human genome, and the specific issues pertinent to pursuing the Genome Project itself, it is truly an exciting time in the development of the biological sciences. The occasion is certainly ripe for the emergence of new concepts and ideas, as the theories of complexity, natural selection, and reductionism become integrated into a new whole. We need to learn how to approach the analysis of the complex data sets that will be generated by the Genome Project and address, more generally, the problems inherent in the analysis of the complex diseases such as asthma. Finally, we need to consider how the recent advances in genetics and genomics will affect biomedical research into the next millennium and beyond.