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

Infant Feeding, Vitamin D and IgE Sensitization to Food Allergens at 6 Years in a Longitudinal Icelandic Cohort

Nordic Nutrition Recommendations (NNR) recommend exclusive breastfeeding until 6 months, partial breastfeeding until 1 year or longer and irrespective of breastfeeding, avoiding solid foods before 4 months. Strong evidence was found for benefits of breastfeeding regarding growth and infections but limited/inconclusive evidence regarding atopic disease and asthma. Vitamin D is of special interest in the Nordic diet. The aim of this prospective study was to compare infant feeding and vitamin D between immunoglobulin E (IgE) sensitized (n = 14) and non-sensitized (n = 130) children at 6 years. Information on diet and vitamin D supplement use were collected with dietary recall (<5 months), 1-d food records (5 and 6 months) and 3-d weighed food records (12 months and 6 years). Serum-specific IgE-antibodies against milk, egg, cod, wheat, soy and peanut (cut-off specific IgE ≥ 0.35 kUA/L) were measured at 6 years and serum 25-hydroxyvitamin D at 12 months and 6 years. At 4 months, 57% of IgE sensitized vs. 23% of non-sensitized children (p < 0.01) had received solid food. At 12 months, IgE sensitized children had a lower intake of vitamin D (median (25th, 75th percentiles): 3.9 μg/d (3.2, 7.2) vs. 8.1 μg/d (4.4, 12.3), p = 0.03) and at 6 years, fewer used vitamin D supplements regularly (23% vs. 56%, p = 0.03). Introduction of solid foods prior to 4 months increased the odds of IgE-sensitization, OR = 4.9 (95%, CI = 1.4–16.6) and vitamin D supplement at 6 years decreased the odds of IgE-sensitization, OR = 0.2 (95%, CI = 0.1–0.98), adjusting for maternal smoking. These observations support the NNR in their recommendation against introducing complementary solid foods before the age of 4 months. Furthermore, they support encouraging vitamin D intake for young children at northern latitudes.

Sensitization to secretoglobin and lipocalins in a group of young children with risk of developing respiratory allergy

BACKGROUND

Multiple sensitizations in early age have been reported to be a risk for development of asthma. This study evaluates the emergence and evolution of IgE to aeroallergens among a cohort of children with physician-diagnosed atopic dermatitis and/or showing food allergy symptoms and to examine the relation to asthma development.

METHODS

Three-hundred and four children (median age 13.4 months at entry) with food allergy symptoms and/or atopic dermatitis without asthma at inclusion were analysed for IgE antibodies against food-, indoor- and outdoor-allergens and pet allergen components and correlated to the individuals' outcome on asthma inception.

RESULTS

At 2 years of follow-up, physician-diagnosed asthma was 19.7% (n = 49) and asthma diagnosed any time was 24% (n = 67). History of persistent cough and asthma of father, combination of milk- and wheat-allergy symptoms and dual sensitization to house dust mite and Japanese cedar were independent risk factors for asthma. Sensitization to dog was the most prevalent inhalant allergen at entry. Asthma children had a higher proportion of sensitization to dog, cat and horse allergens at entry compared with non-asthma children. Being sensitized to both food, house dust mite and pet allergens was strongly associated with asthma (p = 0.0006). Component resolved diagnosis for dog and cat allergens showed that IgE antibodies to Can f 1 and Fel d 1 was common even at very young age.

CONCLUSIONS

Early sensitization to inhalant allergens increases the risk of developing asthma as well as having milk and wheat allergy symptoms. Sensitization to dog, was common at an early age despite dog ownership. Sensitization to secretoglobin and lipocalins and less to serum albumins explained the pet sensitization.

Role of E-selectin and platelet endothelial cell adhesion molecule 1 in gastritis in food allergy patients

Introduction

The prevalence of food allergies and other allergic reactions is increasing worldwide, particularly in highly-urbanized populations. Cell adhesion molecules are expressed in response to various pro-inflammatory cytokines. The expression of intercellular adhesion molecule 1 – ICAM-1 (CD54), ICAM-1 (CD106), P-selectin (CD62P), and E-selectin (CD62E) on vascular endothelial cells is induced by such pro-inflammatory cytokines as tumor necrosis factor α (TNF-α) and interleukin-1 (IL-1).

Aim

To analyze concentrations of E-selectin and platelet endothelial cell adhesion molecule-1 (PECAM-1) in patients with an allergic type of food sensitivity co-existing with gastritis and to compare them to the values determined in individuals with dyspeptic symptoms not associated with allergic disorders.

Material and methods

The study included 80 patients, among them 50 individuals with food sensitivity confirmed based on compulsory standards, and 30 subjects with dyspeptic symptoms not accompanied by allergic conditions. Venous blood samples were taken from each patient and concentrations of E-selectin and PECAM-1 were determined by means of ELISA.

Results

Mean concentrations of sE-selectin and sPECAM-1 in patients with food allergy amounted to 54.0 ±21.6 ng/ml and 132.8 ±31.4 ng/ml, respectively. In individuals without food allergy, mean concentrations of sE-selectin and sPECAM-1 were 57.7 ±17.9 ng/ml and 139.6 ±31.1 ng/ml, respectively. Patients with food allergy and individuals with dyspeptic symptoms not associated with food allergy did not differ significantly in terms of sE-selectin concentrations (Mann-Whitney U-test, p = 0.453028). Similarly, no significant intergroup differences were observed with regard to sPECAM-1 concentrations (Mann-Whitney U-test, p = 0.231054).

Conclusions

Adhesion molecules play an important role in the development of inflammation. This study did not find significant differences in the concentrations of such molecules as sE-selectin and sPECAM-1 between patients with food allergy and gastritis, and subjects in whom gastritis was not accompanied by atopic disorders. A positive correlation between the concentrations of sPECAM-1 and E-selectin was observed in food allergy patients. Consequently, it can be concluded that these molecules participate in the pathogenesis of the inflammatory process independently of the etiopathogenesis of gastritis.

Introduction of complementary foods in infancy and atopic sensitization at the age of 5 years: timing and food diversity in a Finnish birth cohort

OBJECTIVE

To study the associations between timing and diversity of introduction of complementary foods during infancy and atopic sensitization in 5-year-old children.

METHODS

In the Finnish DIPP (type 1 diabetes prediction and prevention) birth cohort (n = 3781), data on the timing of infant feeding were collected up to the age of 2 years and serum IgE antibodies toward four food and four inhalant allergens measured at the age of 5 years. Logistic regression was used for the analyses.

RESULTS

Median duration of exclusive and total breastfeeding was 1.4 (interquartile range: 0.2-3.5) and 7.0 (4.0-11.0) months, respectively. When all the foods were studied together and adjusted for confounders, short duration of breastfeeding decreased the risk of sensitization to birch allergen; introduction of oats <5.1 months and barley <5.5 months decreased the risk of sensitization to wheat and egg allergens, and oats additionally associated with milk, timothy grass, and birch allergens. Introduction of rye <7.0 months decreased the risk of sensitization to birch allergen. Introduction of fish <6 months and egg ≤11 months decreased the risk of sensitization to all the specific allergens studied. The introduction of <3 food items at 3 months was associated with sensitization to wheat, timothy grass, and birch allergens; the introduction of 1-2 food items at 4 months and ≤4 food items at 6 months was associated with all endpoints, but house dust mite. These results were particularly evident among high-risk children when the results were stratified by atopic history, indicating the potential for reverse causality.

CONCLUSIONS

The introduction of complementary foods was consecutively done, and with respect to the timing of each food, early introduction of complementary foods may protect against atopic sensitization in childhood, particularly among high-risk children. Less food diversity as already at 3 months of age may increase the risk of atopic sensitization.

Prevalence of allergen sensitization, most important allergens and factors associated with atopy in children

CONTEXT AND OBJECTIVE

Knowledge of the profile of allergen sensitization among children is important for planning preventive measures. The objective of this study was to assess the prevalence and profile of sensitization to inhaled allergens and food among children and adolescents in an outpatient population in the city of Palmas.

DESIGN AND SETTING

Cross-sectional study at outpatient clinics in Palmas, Tocantins, Brazil.

METHODS

Ninety-four patients aged 1-15 years who were attending two pediatric outpatient clinics were selected between September and November 2008. All of the subjects underwent clinical interviews and skin prick tests.

RESULTS

A positive skin prick test was observed in 76.6% of the participants (72.3% for inhalants and 28.9% for food allergens). The most frequent allergens were Dermatophagoides pteronyssinus (34%), cat epithelium (28.7%), dog epithelium (21.3%), Dermatophagoides farinae (19.1%), Blomia tropicalis (18.1%), cow's milk (9.6%) and grasses (9.6%). A positive skin prick test correlated with a history of atopic disease (odds ratio, OR = 5.833; P = 0.002), a family history of atopic disease (OR = 8.400; P < 0.001), maternal asthma (OR = 8.077; P = 0.048), pet exposure (OR = 3.600; P = 0.012) and cesarean delivery (OR = 3.367; P = 0.019).

CONCLUSION

Dermatophagoides pteronyssinus was the most frequent aeroallergen and cow's milk was the most prevalent food allergen. There was a positive correlation between a positive skin prick test and several factors, such as a family history of atopic disease, maternal asthma, pet exposure and cesarean delivery.

Clinical significance of cross-reactivity between tobacco and latex

BACKGROUND

Allergen cross-reactivity between tobacco and other species of Solanaceae family (tomato, potato, aubergine and egg plant) have been reported. We have recently studied IgE response to tobacco in asthmatic patients sensitised to Lolium perenne (Perennial rye grass pollen) and have found that 30% of the tobacco responsive patients also have latex sensitisation.

OBJECTIVE

The aim of our study was to investigate the possibility of cross-reactivity between tobacco and latex in asthmatic patients with IgE response to latex.

METHODS

A study was performed on tobacco and latex exposure in 15 patients who suffered from asthma and latex sensitisation and who were randomly chosen from our database of latex-sensitive patients. To identify tobacco and latex as possible allergens that might cause clinical specific responses, all these patients were tested with prick-tests, specific IgE to tobacco, latex and related allergens, bronchial challenge, and patch tests with tobacco, latex and nicotine. Immunological response was evaluated with immunoblotting, immunoblotting-inhibition and EAST-inhibition tests.

RESULTS

Positive prick and bronchial challenge with specific IgE>0.35 kU/L to tobacco was demonstrated in 11 asthmatics who were also sensitised to rye grass. Tobacco IgE level was related with sensitisation to latex (p<0.002), but not to other vegetables belonging to the Solanaceae family. EAST-inhibition and immunoblotting-inhibition showed the existence of cross-reactivity between tobacco and latex.

CONCLUSIONS

Cross-reactivity exists between latex and tobacco allergens. Smoker patients with IgE response to tobacco may be a risk population for latex sensitisation.

[Diagnosis and treatment guidelines for difficult-to-control asthma in children]

Children suffering from difficult-to-control asthma (DCA) require frequent appointments with their physician, complex treatment regimes and often admissions to hospital. Less than 5% of the asthmatic population suffer this condition. DCA must be correctly characterised to rule out false causes of DCA and requires making a differential diagnosis from pathologies that mimic asthma, comorbidity, environmental and psychological factors, and analysing the factors to determine poor treatment compliance. In true DCA cases, inflammation studies (exhaled nitric oxide, induced sputum, broncho-alveolar lavage and bronchial biopsy), pulmonary function and other clinical aspects can classify DCA into different phenotypes which could make therapeutic decision-making easier.

Early intervention with suplatast tosilate for prophylaxis of pediatric atopic asthma: a pilot study

The onset of asthma may be related to Th2 cytokine dominance at the time when food allergies occur several months after birth. This study investigated the effectiveness of early intervention with a Th2 cytokine inhibitor (suplatast tosilate) for prevention of asthma in infants with food allergies and atopic dermatitis. Suplatast tosilate dry syrup (6 mg/kg daily) or a histamine H(1)-blocker (ketotifen fumarate dry syrup: 0.06 mg/kg daily) was administered randomly to 53 infants with atopic dermatitis caused by food allergies. The primary endpoints were the incidence of asthma and the time to the onset of wheezing. The peripheral blood Th1/Th2 ratio, total IgE level, and eosinophil count were measured before and after treatment. After 24 months of treatment, the prevalence of asthma was significantly lower in the suplatast group (20.8%) than in the ketotifen group (65.6%, p < 0.01). Additionally, the time from the start of treatment to the initial episode of wheezing for infants who developed asthma was significantly longer in the suplatast group than the ketotifen group (p < 0.01). Furthermore, the eosinophil count was significantly decreased by suplatast treatment (p < 0.05), and there was a significant difference between the suplatast and ketotifen groups with respect to both the eosinophil count (p < 0.01) and the Th1/Th2 ratio (p < 0.05). The results of the present pilot study suggest that suplatast tosilate is useful for the primary prevention of wheezing and asthma in children.

Food allergy is associated with an increased risk of asthma

BACKGROUND

The atopic march is well documented, but the interrelationship of food allergy (FA) and asthma is not well understood.

OBJECTIVE

The aim of this study was to examine the strength of the association and temporal relationships between FA and asthma.

METHODS

This analysis included 271 children >or=6 years (older group) and 296 children <6 years (younger group) from a family-based FA cohort in Chicago, IL. Asthma was determined by parental report of physician diagnosis. FA status was determined based on the type and timing of clinical symptoms after ingestion of a specific food, and results of prick skin test (Multi-Test II) and allergen-specific IgE (Phadia ImmunoCAP). Analyses were carried out using logistic regression accounting for important covariates and auto-correlations among siblings. Kaplan-Meier curves were used to compare the time to onset of asthma with the FA status.

RESULTS

Symptomatic FA was associated with asthma in both older [odds ratio (OR)=4.9, 95% confidence interval (CI): 2.5-9.5] and younger children (OR=5.3, 95% CI: 1.7-16.2). The association was stronger among children with multiple or severe food allergies, especially in older children. Children with FA developed asthma earlier and at higher prevalence than children without FA (Cox proportional hazard ratio=3.7, 95% CI: 2.2-6.3 for children >or=6 years, and hazard ratio=3.3, 95% CI: 1.1-10 for children <6 years of age). No associations were seen between asymptomatic food sensitization and asthma.

CONCLUSIONS

Independent of markers of atopy such as aeroallergen sensitization and family history of asthma, there was a significant association between FA and asthma. This association was even stronger in subjects with multiple food allergies or severe FA.

Use of Phadiatop Infant in diagnosis of specific sensitization in young children with wheeze or eczema

Wheezing and eczema are common symptoms in young children and it is important to disclose sensitization for correct management. The objective of this study was to assess the diagnostic values of Phadiatop Infant, an in vitro test for graded determination of immunoglobulin E (IgE) antibodies to food and inhalant allergens. One-hundred and forty-nine children (median age 1.4 yr) with symptoms of wheezing (51%) eczema (28%) or a combination of both (21%) were classified as atopic or non-atopic based on case history, atopic history, physical examination and determination of IgE antibodies. The clinical performance of Phadiatop Infant was evaluated for 145 children against this classification in a blinded manner to the allergist. Fifty-one children were classified as atopic of which Phadiatop Infant identified 49. Ninety-four were non-atopic of which the test identified 90. This resulted in a sensitivity of 96%, a specificity of 96%, a positive and a negative predictive value of 94% and 98%, respectively. Logistic regression showed that probability had to be assessed as atopic increased with increasing Phadiatop Infant values. These results suggest that Phadiatop Infant can be recommended as an adjunct to the clinical information in the differential diagnosis on IgE-mediated allergy in young children. The test thus provides an opportunity for early correct diagnosis and identification of subjects at risk for whom intervention may be necessary.

Predicting asthma control and exacerbations: chronic asthma as a complex dynamic model

PURPOSE OF REVIEW

Predicting asthma episodes is notoriously difficult but has potentially significant consequences for the individual, as well as for healthcare services. The purpose of this review is to describe recent insights into the prediction of acute asthma episodes in relation to classical clinical, functional or inflammatory variables, as well as present a new concept for evaluating asthma as a dynamically regulated homeokinetic system.

RECENT FINDINGS

Risk prediction for asthma episodes or relapse has been attempted using clinical scoring systems, considerations of environmental factors and lung function, as well as inflammatory and immunological markers in induced sputum or exhaled air, and these are summarized here. We have recently proposed that newer mathematical methods derived from statistical physics may be used to understand the complexity of asthma as a homeokinetic, dynamic system consisting of a network comprising multiple components, and also to assess the risk for future asthma episodes based on fluctuation analysis of long time series of lung function.

SUMMARY

Apart from the classical analysis of risk factor and functional parameters, this new approach may be used to assess asthma control and treatment effects in the individual as well as in future research trials.

Atopic dermatitis in young children is associated with impaired interleukin-10 and interferon-gamma responses to allergens, vaccines and colonizing skin and gut bacteria

BACKGROUND

A significant proportion of children with food allergy and more severe forms of atopic dermatis (AD) go on to develop persistent forms of allergic disease such asthma. Defining immune dysregulation in these children will be of great value in understanding disease pathogenesis.

OBJECTIVE

In this study we characterized the immune responses of young infants (6-18 months of age) with moderate-to-severe AD (a modified SCORAD>or=25) and compared these (n=53) with responses of non-allergic children with no history of dermatitis or sensitization of the same age (n=20).

METHODS

Mononuclear cell cytokine responses to allergens (egg ovalbumin (OVA), beta-lactoglobulin (BLG), house dust mite (HDM)), vaccines (tetanus toxoid (TT), diphtheria toxoid (DT)), intestinal flora (heat-killed Lactobacillus species (HKLB)), heat-killed Staphylococcus aureus (HKSA), S. aureus enterotoxin B (SEB) and mitogen (phytohaemaglutinin (PHA)) were compared in children with AD with unaffected children.

RESULTS

Children with AD had significantly lower spontaneous (unstimulated) production of regulatory cytokine IL-10 (P<0.001), as well as IFN-gamma (P<0.001) and TNF-alpha (P<0.001) compared with the unaffected children. After allowing for differences in baseline levels IL-10 responses to virtually all stimuli (food allergens (P=0.003), vaccines P=0.01, intestinal flora (heat-killed Lactobacillus species (HKLB), P=0.005) and skin flora (heat-killed Staphylococcus aureus (HKSA), P=0.003)) were also significantly attenuated in children with AD. The only exception was HDM, to which responses were stronger in children with AD [P=0.05]. Although there were no significant correlations between HDM IgE and HDM cytokine responses at this age, T-helper type 2 (Th2) IL-5 (P=0.014) and IL-13 (P=0.004) responses to HDM were significantly more frequent in the children with AD. However, while children with AD showed significantly attenuated Th1 IFN-gamma responses to food allergens (OVA, P=0.007 and BLG, P<0.001) and vaccines (DT, P=0.008 and TT, P<0.001), these children showed no difference in Th1 IFN-gamma responses to HDM or microbial agents (HKSA and HKLB).

CONCLUSION

A increase in propensity for Th2 responses to aeroallergens in children with AD is associated with early impaired production of IL-10 regulatory cytokine to a broad range of environmental stimuli including foods, intestinal flora, S. aureus, and vaccines.

Polymorphisms within the PHF11 gene at chromosome 13q14 are associated with childhood atopic dermatitis

Atopic dermatitis is an increasingly common and debilitating childhood disorder that is often accompanied by asthma and allergic rhinitis. Although the pathology of these disorders is distinct, the majority of cases are atopic, typified by elevated serum IgE. A new locus at chromosome 13q14 centred on the genes SETDB2 and PHF11 and associated with increased total serum IgE has recently been identified. Although the precise functions of SETDB2 and PHF11 are not known, both proteins are expressed in cells of the immune system and include conserved domains that suggest a role in chromatin remodelling or transcriptional regulation, respectively. In a family-based association study across the SETDB2 and PHF11 genes, we have identified two single-nucleotide polymorphisms in the PHF11 gene significantly associated with childhood atopic dermatitis in an Australian cohort. These results provide further evidence that this locus is a novel and important regulator of human atopic disease.

Differential diagnosis of IgE-mediated allergy in young children with wheezing or eczema symptoms using a single blood test

BACKGROUND

Allergy-like symptoms are common in young children, but the case history and physical examination cannot identify the underlying origins of overlapping symptom profiles.

OBJECTIVE

To evaluate a blood test, Phadiatop Infant (Pharmacia Diagnostics AB, Uppsala, Sweden), for differentiating the capability of IgE-mediated disease in young children with recurrent wheezing, eczema, or both.

METHODS

One hundred forty-seven children (mean age, 2.0 years) were consecutively referred to 2 allergy centers by their primary care physician for recurrent wheezing, eczema, or both. The allergist's clinical evaluation included medical history, physical examination, skin prick testing with inhalant and food allergens, and specific IgE determinations in blood. The accuracy of Phadiatop Infant was evaluated in a masked manner against the allergist's final diagnosis.

RESULTS

Sixty-nine children had wheezing, 69 had eczema, and 9 had both symptoms. Sixty-one children were clinically diagnosed as having IgE-mediated allergy, 78 as having non-IgE-associated disease, and 8 as having an inconclusive diagnosis. Fifty-six of the 61 children with IgE-mediated allergy had positive Phadiatop Infant test results, and 64 of 78 without the condition had negative results. Sensitivity was 92% and specificity was 82%, with positive and negative predictive values of 80% and 93%, respectively. Thirteen children with a positive Phadiatop Infant test result and a negative final diagnosis were retested after 2 years; 12 of them were diagnosed as having IgE-mediated allergy using a masked evaluation.

CONCLUSIONS

The Phadiatop Infant blood test discriminates between IgE- and non-IgE-mediated symptoms in children younger than 4 years.

How atopic is atopic dermatitis?

BACKGROUND

The extent to which the phenotype of atopic dermatitis (AD) is truly atopic has been the subject of much debate.

OBJECTIVE

We sought to systematically evaluate the evidence for the value of measurement of IgE antibodies in diagnosing AD and whether knowledge of IgE sensitization increases clinical diagnostic and predictive ability.

METHODS

We searched Medline from its inception until September 2003. Only studies that measured atopy as either skin prick test positivity or IgE-antibody sensitization to environmental allergens were included within a descriptive analysis. Because the small number of studies of adequate quality did not allow a formal meta-analysis, we assigned strength of evidence according to predefined quality criteria and ranked studies accordingly.

RESULTS

Inclusion of atopy as part of the diagnostic criteria for AD did not enhance the criteria's sensitivity and specificity in relation to the clinical phenotype of AD. The strength of association between atopy and AD varied significantly between hospital studies (47% to 75%; n=14 studies) and was stronger in hospital than in community populations (7.4% to 78%; n=13 studies). Whereas study quality did not have an effect on atopy prevalence in hospital populations, low atopy prevalences in community surveys were seen in less rigidly conducted studies. AD severity was positively associated with the number of positive skin prick test responses or IgE-antibody levels in 7 of 8 studies that measured both. Only one study suggested that IgE-specific sensitization to hen's egg is associated with subsequent development of AD, and 2 studies found that allergen-specific IgE sensitization in patients with AD is a prognostic marker for allergic airway disease in later life. Atopy-associated AD might also have a worse long-term prognosis than AD that is not associated with atopy.

CONCLUSION

Although atopy is clearly associated with AD, the role of IgE sensitization in AD needs further study. Current evidence suggests that up to two thirds of persons with AD are not atopic, which implies that continued use of the term atopic dermatitis is problematic. Longitudinal studies are needed to compare the treatment response and prognosis of IgE-associated and non-IgE-associated AD.

[Atopic dermatitis. Allergological characteristics and association with respiratory disease]

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease that frequently precedes the development of asthma or other respiratory allergies. The aim of this study was to review allergen sensitization, type of feeding in infancy, and development of asthma or rhinitis in a group of patients with AD.

METHODOLOGY

One hundred children with AD were selected. All patients underwent skin prick and patch tests to foodstuffs and inhalant allergens, total and specific IgE determination, and oral challenge tests.

RESULTS

The study included 57 boys and 43 girls. The mean age at consultation was 3.77 +/- 2.81 years and mean age at onset of of AD was 1.09 +/- 1.69 years. Twenty-eight percent of the children were exclusively sensitized to food allergens, 20% to inhalant allergens and 22% to both food and inhalant allergens. Mean serum IgE levels were higher in children sensitized to Dermatophagoides pteronyssinus (DPT) (346.86 +/- 430.43 U/ml) than in non-sensitized children (78.24 +/- 132.93 U/m) (p < 0.001). Total IgE levels were also higher in patients with respiratory symptoms (283.77 +/- 336.53 U/ml) than in children without respiratory disease (124.62 +/- 285.21 U/ml) (p = 0.021). Thirty-five percent of the children developed some kind of respiratory allergic disease (asthma and/or rhinitis) in a mean interval of 2.55 years after the onset of dermatitis. Of the children sensitized to inhalant allergens (DPT), 55.26 % developed respiratory symptoms compared with 22.58 % of the non-sensitized children (p < 0.001). The odds ratio of developing respiratory allergy if the patient showed sensitization to DPT was 4.235 (95 % CI 1.768-0.147, p = 0.002).

CONCLUSIONS

Children with AD that develops in the first year of life, associated with high IgE levels and early sensitization, independently of the kind of feeding, develop respiratory allergic disease more frequently than children without these factors.

Addressing the prevalence of respiratory allergy in the home environment

Respiratory allergy prevalence has always depended both on genetic predisposition and specific environmental allergenic stimulation that leads to sensitization and eventual symptomatic disease. Changes brought about by modern technology that have afforded a higher quality of life have also accidentally increased the levels of many respirable and ingestible allergens in the environment. In many cases these higher levels of exposure have exceeded individual thresholds, resulting in the phenotypic expression of allergy in many individuals who were previously asymptomatic even though they were genotypically predisposed to developing allergies. Prevalence can be decreased only if susceptible populations are identified as early as possible through careful family history taking and appropriate testing for sensitivity and if exposure to selected allergens is controlled.

Genetic variants of the IL13 and IL4 genes and atopic diseases in at-risk children

We studied a cohort containing 368 children at high risk of developing atopy and atopic disorders and 540 parents of those children to investigate whether the IL13 Arg130Gln and C-1112 T polymorphisms were associated with these outcomes. We also investigated whether haplotypes consisting of any two polymorphisms of IL13 Arg130Gln, IL13 C-1112 T and IL4 C-589 T were associated with these phenotypes. In 288 white children, the IL13 130Gln allele was associated with atopy (RR=1.9, P=0.047), and with atopic dermatitis (RR=2.5, P=0.014). The associations were confirmed using a family-based test of association (P=0.027 and 0.030, respectively) in all subjects. In white subjects there were associations of haplotypes consisting of IL13 Arg130Gln and IL4 C-589 T with atopic dermatitis (P=0.006) and with atopy (P=0.009). Our data suggest that the IL13 Arg130Gln polymorphism and haplotypes consisting of IL13 Arg130Gln and IL4 C-589 T were associated with the development of atopy and atopic dermatitis at 24 months of age.

Early sensitisation and development of allergic airway disease - risk factors and predictors

The development and phenotypic expression of allergic airway disease depends on a complex interaction between genetic and several environmental factors, such as exposure to food, inhalant allergens and non-specific adjuvant factors (e.g. tobacco smoke, air pollution and infections). The first months of life seem to be a particularly vulnerable period and there is evidence that sensitisation is related to the level of allergen exposure during early life. At present, the combination of atopic heredity and elevated cord-blood IgE seems to result in the best predictive discrimination as regards development of allergic disease at birth. Early sensitisation, cow's milk allergy and atopic eczema are predictors for later development of allergic airway disease. Exposure to indoor allergens, especially house dust mite allergens, is a risk factor for sensitisation and development of asthma later in childhood in high-risk infants and infants with early atopic manifestations.

Increased serum IL-10/IL-12 ratio in wheezing infants

To investigate the association between various serum markers and atopic symptoms in the first year of life, and to evaluate the prognostic value of these markers for the development of wheezing and skin rash in the second year of life. Data of 86 children on the development of wheezing and skin rash in the first 2 years of life were collected prospectively, making use of parental completed questionnaires, weekly symptom cards, structured interview and physical examination. Serum markers (IL-10, IL-12, IL-13, eotaxin, sE-selectin, sICAM-1, sIL-2R) and total and specific IgE were determined at age 1. Children who developed wheezing in the first year of life had lower serum levels of IL-12 than children without symptoms (median 40.3 pg/ml vs. 49.0 pg/ml, p = 0.01) and a higher serum IL-10/IL-12 ratio (0.41 vs. 0.31, p = 0.001) at age 1. The IL-10/IL-12 ratio increased with an increasing number of wheezing episodes. Levels of sE-selectin in children with wheezing and in children with itchy skin rash in the first year of life were higher than in symptom free children (6.1 ng/ml and 5.9 ng/ml vs. 4.9 ng/ml, p = 0.01 and p = 0.03, respectively). Children who developed wheezing in the second year of life already had increased sICAM-1 levels at age 1. Children who developed wheezing in the first year of life showed a serum cytokine response that is skewed towards a T-helper 2 profile, with lower IL-12 levels and an increased IL-10/IL-12 ratio. Children who developed wheezing in the second year of life had elevated sICAM-1 levels at age 1. Follow-up of the children is needed to evaluate the prognostic value of various serum markers for the development of allergic disease in later childhood.

Hay fever and predictive value of prick test and specific IgE antibodies: a prospective study in children

Little is known from population-based studies in children about the diagnostic values of allergen-specific IgE antibodies (RAST) and skin prick test (SPT) with respect to hay fever. We aimed to determine and compare the diagnostic values of SPT and RAST to aeroallergens with respect to the incidence of hay fever cases in schoolchildren at different cut-off points. A prospective cohort study was performed on 1100 school children (5-7 and 8-10 years). Information on a doctor's diagnosis of hay fever was obtained by questionnaire and allergic sensitization to grass and birch pollen, cat, and Dermatophagoides pteronyssinus were measured using SPT and RAST between September 1992 and July 1993. Thirty-eight children give a history of hay fever (3.5%) in 1992/93 and additionally 37 cases occurred until 1996. Allergic sensitization was present in 17.9% (SPT), 30.2% (RAST) and more frequent in children with a history of hay fever (SPT: OR 11.7, 5.5-24.7; RAST: OR 10.6, 4.3-26.4). This difference was most pronounced for sensitization to pollen allergens. The sensitivity, specificity, positive and negative predictive values (PPV, NPV) for SPT and RAST were 65.6, 83.7, 11.9, 98.6 and 79.3, 71.6, 9.3, 99.0, respectively, with differences for specificity being significant (p < 0.001). Whereas NPV were equally high for SPT (99.2) and RAST (99.3), the incidence of hay fever cases were predicted rather poorly though somewhat better by SPT than by RAST (PPV 16.7 vs. 9.8; p < 0.001) initially. With increasing cut-off point for RAST reactivity, the PPV increased and reached 25.0 at 17.5 kU/l, whereas the NPV decreased to 97.9, which was lower than that of SPT reactivity (p < 0.01). At the cut-off point of 1.5 kU/l almost identical predictive values for SPT and RAST were obtained. SPT and RAST perform better in the negative than positive prediction of hay fever cases in epidemiological studies. Differences in the predictive capabilities depend on the chosen cut-off point for RAST reactivity.

Natural course of cow's milk allergy in childhood atopic eczema/dermatitis syndrome

OBJECTIVE

This review was undertaken to determine the role of adverse reactions to bovine proteins in atopic dermatitis, recently called atopic eczema/dermatitis syndrome (AEDS).

DATA SOURCES

A PubMed literature search was conducted with use of the following phrases: atopic dermatitis and food allergy, atopic dermatitis and cow's milk, and cow's milk and eczema.

STUDY SELECTION

The authors' judgment and personal interest guided the literature selection.

RESULTS

Food allergy has a role in at least 20% of the cases of AEDS in children younger than 4 years. Cow's milk is usually the first food given to an infant, and cow's milk hypersensitivity is often the first symptom of an atopic condition. Adverse reactions to cow's milk proteins are usually categorized as immunoglobulin (Ig)E-mediated or non-IgE-mediated cow's milk allergy and nonallergic hypersensitivity (intolerance); the symptoms do not allow differentiation of these entities. In patients with cow's milk allergy and AEDS, resolution occurs in 90% by the age of 4 years. Non-IgE-mediated cow's milk allergy often disappears before the age of 1 year. Associated reactions to other foods develop in approximately 45% of patients. Allergy to potential environmental inhalant allergens has been reported in up to 28% of patients by 3 years of age and up to 80% before puberty. After consumption of large amounts of cow's milk, 45% of 10-year-old children who had become tolerant of cow's milk, but also 15% of control subjects, still had gastrointestinal complaints. The presence of cow's milk allergy during infancy increases the risks for development of other food allergies, respiratory atopy, and persistence of AEDS.

CONCLUSION

Adverse reactions to bovine proteins have an important role in AEDS.

Environmental factors relevant to difficult asthma

Symptom persistence in difficult asthmatics may be related to their home environment. If sensitised asthmatics are to benefit from indoor allergen avoidance measures, these must be rigorous and drug adherence satisfactory. This is difficult for many families. The relationship between traffic pollution, asthma diagnosis and symptom severity is persuasive but requires objective validation. Overall, it seems that house dust mite control and tobacco smoke avoidance are important for asthmatics and advice about how to avoid these adverse factors must be given. Whether these measures are effective in difficult asthmatics and whether moving house makes any difference is unknown.

Preventive measures and their effects. Results from cohort studies

The prevalence of asthma and atopic diseases continues to rise. Genetic factors alone cannot explain this rapid rise and the immunological mechanisms involved are insufficiently explained to allow direct intervention on a population-wide scale. Long-term observational birth cohort studies have provided data on which primary prevention studies are based. This review discusses the "who", "how", "when" and "what" of primary prevention and the experiences to date in prospective intervention cohort studies.

Effect of exclusive breast-feeding and early solid food avoidance on the incidence of atopic dermatitis in high-risk infants at 1 year of age

The aim of this study was to assess the preventive effect of exclusive breast-feeding and early solid food avoidance on atopic dermatitis (AD) in infancy. This study is part of a dietary clinical trial in a prospective cohort of healthy term newborns at risk of atopy. It was recommended to breast-feed for at least 4 months and to avoid solid food in the same time-period. Eight hundred and sixty-five infants exclusively breast-fed, and 256 infants partially or exclusively formula-fed, were followed-up until the end of the first year following birth. AD and sensitization to milk and egg were considered as study end-points. The 1-year incidence of AD was compared between the two study groups. Adjusted odds ratios (OR) with 95% confidence intervals (CI) were calculated by multiple logistic regression. The incidence of AD was calculated in relation to age at introduction of solid food and amount of food given. In the breast-fed group, the adjusted OR for AD was 0.47 (95% CI 0.30-0.74). The strongest risk factor was the occurrence of AD in the subject's core family. The risk of infants with AD to be sensitized to milk was four times higher, and to egg eight times higher, than in infants without AD. Age at first introduction of solid food and diversity of solid food showed no effect on AD incidence. We conclude that in infants at atopic risk, exclusive breast-feeding for at least 4 months is effective in preventing AD in the first year of life.

Issues in understanding pediatric asthma: epidemiology and genetics

Asthma is a heterogeneous disease characterized by varying phenotypes. Ongoing research is focused on identifying which children who have wheezing early will progress to childhood asthma. Genetic factors, predominantly atopy and a parental history of asthma as well as environmental stimuli, are key components in the development of asthma. Investigation into immunologic processes indicates that atopic children may have a cytokine imbalance or dysregulation in which the transition from T helper 2 (T(H)2)-type to T(H)1-type immunity is delayed. Several risk factors have been identified in the pathophysiology of asthma, including sensitization and exposure to cockroaches, house dust mites, and the mold Alternaria alternata, among other aeroallergens. Viral respiratory infections, primarily those caused by respiratory syncytial virus, are a significant risk factor for the development of childhood wheezing in the first decade of life. A number of prospective epidemiologic studies are investigating, among other issues, the relations among cytokine dysregulation, respiratory tract infections, and allergen exposure and sensitization in the development of asthma. Identifying the pathogenic mechanisms should enable clinicians to identify children at high risk and thereby to treat childhood asthma more effectively.

Perceptions of physicians and pediatric patients about atopic dermatitis, its impact, and its treatment

The National Eczema Association for Science and Education surveyed 429 patients with atopic dermatitis or their parents and 303 physicians about atopic dermatitis, its effect on quality of life (QOL), and the adequacy of available treatments. The physician survey focused on disease severity and management; the patient survey, on disease severity, impact on QOL, and treatment preferences. Physician and patient/parent respondents generally agreed about their assessments of disease severity, poor effectiveness of over-the-counter products, and the need for more patient support groups and toll-free phone information. Atopic dermatitis significantly impacts QOL in children, particularly in those with moderate-to-severe disease. New treatments should offer enhanced efficacy, less frequent application, and fewer adverse effects.

[Etiologic implication of foods in atopic dermatitis: evidence in favor]

Some of the immunopathologic mechanisms involved in IgE responses are currently being identified; Th2 lymphocytes are known to be activated in patients with atopic dermatitis with subsequent production of the cytokines interleukin (IL)-4 and IL-5, which are responsible for IgE production and eosinophil recruitment. Nevertheless, T cell activation in this disease takes place in two phases. In the first phase, Th2 cells are activated and IL-4, IL-5 and IL-13 are produced; this first stage is produced with the initial activation induced by the antigen. In the second phase there are chronic lesions, Th1 lymphocytes are activated and IFg is produced. This chronic phase is associated with the presence of eosinophils and macrophages that produce IL-12.Numerous articles have demonstrated food sensitization to be an etiopathogenic factor in atopic dermatitis. The prevalence of sensitization varies, depending on the patient's age and the severity of the disease. Children with moderate-to-severe atopic dermatitis have been observed to have a positive skin test and high IgE concentrations to various foods. Nevertheless, a positive skin test to foods in such children does not always implicate these foods as the cause of the clinical manifestations; moreover, in children showing subsequent tolerance to these foods, skin tests can sometimes remain positive and high levels of specific IgE can persist. It is now known that IgE not only participate in the degranulation of mastocyte cells but also in reactions mediated by T cells and other antigen-presenting cells (dendritic cells) which have high-affinity receptors for IgE.The immediate IgE response is well known but it is also known that in addition to the immediate response, a delayed response is also involved, evidenced by the presence of antigen-specific T cells to foods or other allergens such as inhalant allergens. After a strict exclusion diet, children with atopic dermatitis and sensitivity to foods such as milk, egg, flour and soya can develop tolerance; for this reason provocation tests with the food in question should be repeated every 2-3 years. In children with sensitivity to other foods such as dried fruits, fish, and shellfish, sensitivity can sometimes persist into adulthood without tolerance being achieved. In conclusion, there are two groups of children with atopic dermatitis. One group consists of those with atopic dermatitis (allergic disease), which is characterized by early development, high IgE titers, the presence of antigen-specific IgE to allergens and a family history of atopy and which is clinically moderate or severe. Early diagnosis and treatment are important in these children, as is the prevention of progression of the disease to bronchial asthma. The other group consists of children whose dermatitis is clinically atopic in terms of its localization and morphology, who have no demonstrable allergic disease and whose management differs from that in children presenting allergic disease.

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.

Elevated serum concentrations of beta-tryptase, but not alpha-tryptase, in Sudden Infant Death Syndrome (SIDS). An investigation of anaphylactic mechanisms

BACKGROUND

Sudden Infant Death Syndrome, (SIDS) or cot death, remains the most common category of post-perinatal death in the UK. By definition, the cause of death is unknown, but a long-standing theory is that some of these deaths could be the result of anaphylaxis.

OBJECTIVE

To investigate the potential contribution of anaphylactic mechanisms to deaths in infancy by determining relative levels of alpha- and beta-tryptases and both total and allergen-specific IgE in sera from groups of infants whose deaths were attributed to SIDS or to other causes.

METHODS

Serum samples were collected at the time of post-mortem examination from infants whose death was classed as SIDS (n = 40) and from a comparison group in which cause of death had been established (n = 32). Serum tryptase concentrations were measured with a radioimmunoassay with monoclonal antibody G5 which detects primarily beta-tryptase or an ELISA with antibody AA5 which has equal sensitivity for alpha- and beta-tryptases. Levels of total IgE and IgE specific for casein, beta-lactoglobulin, house dust mite and moulds were determined.

RESULTS

Analysis of the results of the two assays for tryptase indicated that levels of the beta-like tryptase (the form secreted on anaphylactic degranulation) were significantly higher in serum from infants with SIDS compared with those whose death was explained. There was no evidence for an increase in serum levels of alpha-tryptase (the variant secreted constitutively from mast cells). Total levels of serum IgE did not differ between the two groups and, reflecting the low circulating IgE concentrations in infancy, an elevation in IgE specific for the panel of allergens was not detected.

CONCLUSIONS

In a proportion of SIDS victims there may be increased serum levels of beta-like tryptase, a marker for anaphylaxis. The failure to detect an increase in alpha-tryptase would suggest that mast cell hyperplasia is not a feature of cot death. The nature of the inciting agents remains unclear, but anaphylaxis deserves serious consideration as a possible cause of sudden death in infancy.

Early introduction of cereals into children's diets as a risk-factor for grass pollen asthma

BACKGROUND

The prevalence of asthma has increased from the 1950s to the 1990s. The relationship between diet and asthma is an area of controversy that has never been fully evaluated. Attempts at dietary prevention of asthma have produced conflicting results. We have recently identified allergens from cereals that show cross-reactivity with proteins in grass pollen. An early intake of cereals in the diet during early life might cause IgE sensitization to cereals. It is not known whether such sensitization predisposes the development of allergy to pollen.

METHODS

To test this hypothesis, a cross-sectional study and an observational case-control analysis of reviewed data were carried out on 16381 patients who had been admitted to our Allergy Unit between 1989 and 1999. All the patients underwent allergy tests to identify asthma risk-factors. All information in our data base was analysed using the SPSS computer system.

RESULTS

There has been an increase of 7.8% in incidences of allergic asthma and a 7.3% increase in asthma due to grass pollen in the last decade. Grass-pollen asthma was associated with sensitization to cereals. The early introduction of cereals in the diet of children was found to be a risk factor for grass-pollen asthma (OR = 5.95; 95% CI 3.89-9.10).

CONCLUSIONS

These findings document the progression of allergic asthma during a decade in a large sample of people who were influenced by similar environmental conditions and studied with the same diagnostic methods. This study represents the largest database of patients in which a common food is shown to be a risk factor for asthma.

Selective development of a strong Th2 cytokine profile in high-risk children who develop atopy: risk factors and regulatory role of IFN-gamma, IL-4 and IL-10

BACKGROUND

The immunological processes in early life and their relation to allergic sensitization leading to a Th2 cytokine profile are still not well understood.

OBJECTIVE

To analyse the environmental and genetic risk factors and immunological responses at birth in relation to the development of atopic disease at 12 months of age in a longitudinal study of high-risk children.

METHODS

High-risk children were followed from birth till 12 months of age. Mononuclear cells obtained at birth and 6 and 12 months thereafter were analysed for their proliferative and cytokine responses after polyclonal and allergen-specific stimulation.

RESULTS

At 12 months of age 25% children had developed an atopic disease. Two atopic parents, parental smoking and atopic dermatitis of at least one of the parents were significant risk factors. In cord blood of newborns who developed atopy, an increased percentage of CD4+CD45RO+ cells and an increased polyclonal-stimulated proliferation were observed. Furthermore, an impaired allergen-induced, but not polyclonal-stimulated IFN-gamma production was found, suggesting a regulatory defect. At 6 and 12 months of age, a strong Th2 profile (characterized by increased levels of IL-4, IL-5, and IL-13) after both polyclonal and, to a lesser extent, allergen-specific stimulation was found in the children developing atopy. Allergen-induced IL-10 production at 12 months of age was only observed in the non-atopic children.

CONCLUSION

Our data indicate that the first 6 months of life represent a critical time window for the initiation of immunological changes resulting in the development of atopy. The selective development of a Th2 cytokine profile in high-risk children who develop atopy is due to increased production of Th2 cytokines, possibly caused by impaired allergen-induced IFN-gamma production in the neonatal period. Furthermore, the decreased allergen-induced IL-10 levels observed in the atopic children at 12 months of age may result in a lack of down-regulation of the inflammatory process.

Immunotherapy in atopic dermatitis

Atopic dermatitis (AD) is a common inflammatory disease involving the skin and often other organs and systems, mainly respiratory. A definitive general consensus on the AD pathogenesis has not yet been established, however several lines of evidence suggest that T-cells play a crucial role in priming AD early-stage lesions. Main topics involved in the disease pathogenesis have been reviewed, which considered the concept of local and systemic haemopoietic events as important contributors to allergic inflammation, a concept now achieving great acceptance. The recently recognised atopic nature of the skin inflammation in AD has raised increasing interest for treatment with allergen-specific immunotherapy. However, we only found eight studies using specific immunotherapy (SIT) in AD, two double-blind, placebo-controlled (DBPC) and six observational. One controlled and five observational reported favourable outcomes. The one unique study providing negative results was flawed by the ineffective oral route of extract administration. Despite being encouraging, the reported results do not allow definitive conclusions based on meta-analytic techniques because the amount and quality of information in the literature is not sufficient. The highly promising sub-lingual immunotherapy (SLIT) is discussed with its potential capability of controlling not only the skin lesion severity but also its capability of preventing the development of atopic dermatitis into asthma.