Serum IgE levels during the first 6 years of life

The Very Low IgE Producer: Allergology, Genetics, Immunodeficiencies, and Oncology

Opposite to other immunoglobulin (Ig) classes and subclasses, there is no consensus on the definition of normal levels of serum total IgE. However, longitudinal studies on birth cohorts produced growth charts of total IgE levels in helminth-free and never atopic children and defining the normal ranges of total serum IgE concentration at the individual, rather than population, level. Accordingly, very 'low IgE producers' (i.e., children whose tIgE level belong to the lowest percentiles) became atopic while keeping their total IgE levels in a range considered 'normal' if compared to the general age-matched population but 'abnormally high' if projected on the tIgE growth chart against the trajectory of that child's own percentile levels. In 'low IgE producers', the IgE-specific activity, i.e., the ratio between allergen-specific and total IgE, is more important than the absolute specific IgE levels to confirm causality between allergen exposure and allergic symptoms. Patients with allergic rhinitis or peanut anaphylaxis but low or undetectable allergen-specific IgE levels must therefore be reconsidered considering their total IgE levels. Low IgE producers have been also associated with common variable immunodeficiency, lung diseases, and malignancies. A few epidemiological studies have shown a higher risk of malignancies in very low IgE producers, leading to a debated hypothesis proposing a novel, evolutionistic-relevant function for IgE antibodies for antitumor immune surveillance.

Allergic Rhinitis in Childhood and the New EUFOREA Algorithm

Allergic rhinitis in childhood has been often missed, mistreated and misunderstood. It has significant comorbidities, adverse effects upon quality of life and educational performance and can progress to asthma or worsen control of existing asthma. Accurate diagnosis and effective treatment are important. The new EUFOREA algorithm provides a succinct but wide- ranging guide to management at all levels, based on previous guidelines with updated evidence and has been adjusted and approved by experts worldwide.

Perimenstrual Asthma in Adolescents: A Shared Condition in Pediatric and Gynecological Endocrinology

Asthma is a frequent medical condition in adolescence. The worsening of the most common symptoms perimenstrually is defined as perimenstrual asthma (PMA). The cause of PMA remains unclear, but a role for hormonal milieu is plausible. Data on PMA in adolescents are limited, and its management is not fully established. We aimed to discuss the PMA phenomenon in young females from pathophysiology to preventive strategies, focusing on the relationship with the hormonal pattern. The fluctuation of estrogens at ovulation and before menstruation and the progesterone secretion during the luteal phase and its subsequent withdrawal seem to be the culprits, because the deterioration of asthma is cyclical during the luteal phase and/or during the first days of the menstrual cycle. Conventional asthma therapies are not always effective for PMA. Preventive strategies may include innovative hormonal contraception. Even a possible beneficial effect of other hormonal treatments, including estrogens, progestogens, and androgens, as well as leukotriene receptor antagonists and explorative approach using microbial-directed therapy, is considered. The underlying mechanisms, through which sex-hormone fluctuations influence asthma symptoms, represent a challenge in the clinical management of such a distressing condition. Further studies focused on young females are mandatory to promote adolescent health.

Hormones, sex, and asthma

OBJECTIVE

To summarize the current literature on the sex disparity in asthma and the role of sex hormone signaling in allergic and neutrophilic airway inflammation.

DATA SOURCES

PubMed and Centers for Disease Control and Prevention health surveys were searched.

STUDY SELECTIONS

Clinical and epidemiologic studies in children and adults as well as animal models of asthma were included in this review.

RESULTS

Compared with males, females have an increase in asthma prevalence starting around puberty, and fluctuations in hormones during menstruation, pregnancy, and menopause are associated with changes in asthma symptoms. Animal studies using genetic deletions of estrogen receptors or androgen receptors have shown that estrogen signaling promotes and androgen signaling attenuates allergen-mediated type 2 airway inflammation. Furthermore, animal studies have found that ovarian hormones are important for interleukin 17A-mediated airway inflammation.

CONCLUSION

Sex hormones are important in regulating asthma pathogenesis. However, additional studies need to be conducted to further elucidate how sex hormones are initiating and driving the inflammatory response(s) in asthma. Determining these pathways will provide the foundation necessary for the development of treatment strategies and potentially new therapeutics for patients, in particular females, with asthma.

Growth curves of "normal" serum total IgE levels throughout childhood: A quantile analysis in a birth cohort

BACKGROUND

Previous studies of serum total IgE (t-IgE) were not able to discriminate well-enough atopic from non-atopic subjects, that is, with or without serum-specific IgE antibodies to allergens.

OBJECTIVES

To model growth curves of the total IgE levels in children without atopic sensitization (hereafter defined as "normal" t-IgE levels) and to test their usefulness in predicting atopic sensitization.

METHODS

The German Multicentre Allergy Study (MAS), a birth cohort with 1314 recruited newborns, began in 1990 and examined the participants until age 20 years. Total and specific IgE (t-IgE, s-IgE) were analyzed with a fluorescent enzyme immunoassay ImmunoCAP (TFS, Sweden) at ages 1, 2, 3, 5, 6, 7, 10, 13, and 20 years. Participants were classified as "never atopic" if all their available serum samples had negative response (cutoff: <0.35 kU_A /L) for s-IgE to the nine common foodborne and airborne allergenic extracts (milk, egg, soy, wheat, house dust mite, cat, dog, birch, and grass) tested in the MAS birth cohort. By contrast, participants were defined as atopic if they had, for at least at one available serum sample, s-IgE≥0.35 kU_A /L to at least one allergenic extract tested. The evolution of t-IgE levels in the "never atopic" children was described by growth curves, estimated by exploiting a quantile regression model. A "reference" percentile, based on the t-IgE value measured at age 5 years, was assigned to each child with no IgE sensitization at that age. Upward deviations from the own "reference" quantile of t-IgE in atopic and "never atopic" children were calculated and a ROC analysis was used to identify the best cutoff point for predicting atopic sensitization.

RESULTS

Overall, 1113 of 1314 children were included in this analysis. Of these, 469 were "never atopic" and 644 atopic. Quantile trajectories of t-IgE levels in "never atopic" subjects were stable from 5 years of age, increased to a plateau at age 10-13 years, and decreased slightly afterward. The onset of atopic s-IgE responses was characterized by an upward deviation of serum t-IgE levels from their "reference" trajectory. T-IgE quantiles predicted the onset of atopy with high efficiency (AUC>80%). ROC analysis showed that deviations from the t-IgE level "reference" quantile above 0.32, 0.41, 0.42, 0.30, and 0.58 kU/L (log-units) at 6, 7, 10, 13, and 20 years of age, respectively, predicted an atopic sensitization.

CONCLUSION

The growth curves of "normal" serum t-IgE concentrations were estimated in "never atopic" children; for each individual who was non-atopic at 5 years of age a "reference" quantile was identified that represented the individual's "normal" level of t-IgE production. Upward deviations of observed t-IgE levels from the own "reference" quantile, from 6 to 20 years of age, predicted at each year the occurrence of atopic sensitization.

CLINICAL IMPLICATIONS

The trajectory of t-IgE levels can be elaborated since age 5 years in non-atopic children. A child whose t-IgE levels are consistently higher than those predicted by his/her growth curve may have developed atopic sensitization.

Reference Values and Utility of Serum Total Immunoglobulin E for Predicting Atopy and Allergic Diseases in Korean Schoolchildren

The present study aimed to investigate the distribution of total serum immunoglobulin E (IgE) levels in Korean schoolchildren and to evaluate its utility in the prediction of atopy and allergic diseases. A nationwide, cross-sectional survey was conducted in first grade students from randomly selected elementary and middle schools. Total IgE levels were measured by ImmunoCAP. Skin prick tests were performed for 18 common inhalant allergens to determine the presence of atopy. Children aged 12-13 years and parents of children aged 6-7 years were asked to complete questionnaire assessing allergic diseases. The cut-off levels of total IgE were determined by analyzing receiver operating characteristic curves. The median total IgE level was 86.7 kU/L (range: 1.5-4,523.1) in 3,753 children aged 6-7 years and 94.7 kU/L (range: 1.5-3,000.0) in 3,930 children aged 12-13 years. Total IgE concentrations were higher in children with atopy or allergic diseases than in those without (all P < 0.001). At the cut-off value of 127.7 kU/L, sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were 67.1%, 75.4%, 65.4%, and 76.7%, respectively, in elementary schoolchildren. At the cut-off value of 63.0 kU/L, sensitivity, specificity, PPV, and NPV were 81.9%, 66.6%, 75.0%, and 75.1%, respectively, in middle schoolchildren. PPV and NPV were ≥ 70% when cut-offs of 258.8 kU/L and 38.4 kU/L were used for the diagnosis of atopy in 6-7 year-olds and 12-13 year-olds, respectively. This nationwide population-based study provided the first normal reference ranges of total IgE in Korean schoolchildren.

In-vitro diagnostic in atopic dermatitis: Options and limitations

Atopic dermatitis is a chronic inflammatory skin disease with a complex pathogenesis and different exogenous and endogenous trigger factors. One important factor is the sensitization to inhalant and/or food allergens. The detection of total IgE and specific IgE antibodies to inhalant and/or food allergens is one central aspect in diagnosing atopic dermatitis, especially if skin prick tests are not feasible. Many patients are polysensitized, but not all sensitizations are of clinical relevance. The challenge is to identify the sensitizations with clinical relevance and to initiate suitable therapeutic options. In this article we go into detail for the allergens house dust mite, pollen, food, and Malassezia sympodialis. Furthermore, the authors comment on the impact of the detection of specific IgG/IgG4 antibodies in the diagnosis of food allergy in atopic dermatitis. Moreover, new options in the in-vitro diagnostic will be explained briefly and their actual diagnostic significance in patients with atopic dermatitis will be highlighted. These options are the detection of specific IgE antibodies to recombinant allergens and the allergen chip.

Impact of interleukin 13 (IL13) genetic polymorphism Arg130Gln on total serum immunoglobulin (IgE) levels and interferon (IFN)-γ gene expression

This cross-sectional study was designed to investigate the extent of genetic susceptibility by targeting variants in interleukin (IL)-4/IL-13 signalling pathways leading to atopic disease in early childhood. We evaluated involvement of five single nucleotide polymorphisms IL4 C-590T, IL13 C-1055T, IL13 Arg130Gln, IL4RA Ile50Val and IL4RA Gln576Arg, in the control of serum total and antigen-specific immunoglobulin (Ig)E levels. Furthermore, we analysed their association with changes in gene expression of five cytokines having key roles in inflammatory and anti-inflammatory immune response [IL-4, IL-13, interferon (IFN)-γ, IL-8 and IL-10]. Total and antigen-specific IgE levels in serum and gene expression of selected cytokines in peripheral blood were measured in 386 children aged 1-8 years. TaqMan allelic discrimination, amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) and restriction fragment length polymorphisms (RFLP) methods validated by sequencing were used for genotyping. All genotypes for children with total and antigen-specific IgE levels in the normal range were in Hardy-Weinberg equilibrium. Gene expression analyses were carried out using TaqMan gene expression assays. We found elevated total IgE levels in carriers of IL13 Arg130Gln variant allele [odds ratio (OR) = 1·84; 95% confidence interval (CI) = 1·16-2·93]. This effect was more apparent for boys (OR = 2·31; 95% CI = 1·25-4·28). However, no significant association was observed for the other four variants examined. We found up-regulation of IFN-γ in children with elevated serum total IgE levels carrying the Arg130 allele (P = 0·005). No differences were found for IL4, IL8 or IL10, while IL13 gene expression was under the detection limit. IL13 Arg130Gln genotypes can play a role in genetic susceptibility to allergy via regulation of serum total IgE levels and affecting IFN-γ gene expression.

Hyper IgE in Childhood Eczema and Risk of Asthma in Chinese Children

BACKGROUND

Atopic eczema is a common childhood disease associated with high IgE and eosinophilia. We characterized the clinical features associated with hyper-IgE (defined as IgE > 2000 IU/L) in eczema.

METHODS

Nottingham Eczema Severity Score (NESS), family and personal history of atopy, skin prick test (SPT) for common food and aeroallergens, highest serum IgE ever and eosinophil counts were evaluated in 330 children eczema patients. Childhood-NESS (NESS performed at <10 years of age) and adolescent-NESS (NESS performed at >10 years of age) were further analyzed.

RESULTS

IgE correlated with NESS (spearman coefficient 0.35, p < 0.001) and eosinophil percentage (spearman coefficient 0.56, p = 0.001). Compared with IgE ≤ 2000IU/L (n = 167), patients with hyper-IgE (n = 163) were associated with male gender (p = 0.002); paternal atopy (p = 0.026); personal history of atopic rhinitis (p = 0.016); asthma (p < 0.001); dietary avoidance (p < 0.001); use of wet wrap (p < 0.001); traditional Chinese medicine use (TCM, p < 0.001); immunomodulant use (azathioprine or cyclosporine, p < 0.001); skin prick sensitization by dust mites (p < 0.001), cats (p = 0.012), dogs (p = 0.018), food (p = 0.002); eosinophilia (p < 0.001); more severe disease during childhood (p < 0.0001) and during adolescence (p < 0.0001), but not onset age of eczema or maternal atopy. Logistic regression showed that hyper-IgE was associated with personal history of asthma (exp(B) = 5.12, p = 0.002) and eczema severity during childhood and adolescence (p < 0.001). For patients <10 years of age, dust mite sensitization (p = 0.008) was associated with hyper-IgE. For patients >10years of age, food allergen sensitization was associated with hyper-IgE (p = 0.008).

CONCLUSIONS

Hyper-IgE is independently associated with asthma, more severe atopy and more severe eczema during childhood and adolescence. IgE > 2000 IU/L may be a tool to aid prognostication of this chronic relapsing dermatologic disease and its progression to asthma.

Genome-wide interaction studies reveal sex-specific asthma risk alleles

Asthma is a complex disease with sex-specific differences in prevalence. Candidate gene studies have suggested that genotype-by-sex interaction effects on asthma risk exist, but this has not yet been explored at a genome-wide level. We aimed to identify sex-specific asthma risk alleles by performing a genome-wide scan for genotype-by-sex interactions in the ethnically diverse participants in the EVE Asthma Genetics Consortium. We performed male- and female-specific genome-wide association studies in 2653 male asthma cases, 2566 female asthma cases and 3830 non-asthma controls from European American, African American, African Caribbean and Latino populations. Association tests were conducted in each study sample, and the results were combined in ancestry-specific and cross-ancestry meta-analyses. Six sex-specific asthma risk loci had P-values < 1 × 10(-6), of which two were male specific and four were female specific; all were ancestry specific. The most significant sex-specific association in European Americans was at the interferon regulatory factor 1 (IRF1) locus on 5q31.1. We also identify a Latino female-specific association in RAP1GAP2. Both of these loci included single-nucleotide polymorphisms that are known expression quantitative trait loci and have been associated with asthma in independent studies. The IRF1 locus is a strong candidate region for male-specific asthma susceptibility due to the association and validation we demonstrate here, the known role of IRF1 in asthma-relevant immune pathways and prior reports of sex-specific differences in interferon responses.

Food allergy testing

Food allergy (IgE-mediated hypersensitivity) is a common clinical problem affecting approximately 15% of children in the Western world. These hypersensitivity reactions tend to be "immediate" (typically within minutes of food exposure), and clinical features may range from mild to life threatening (anaphylaxis). Detailed clinical history is critical to correct diagnosis. Available laboratory tests have limitations not least poor positive predictive value and limited repertoire. Laboratory tests should support clinical diagno sis not vice versa.

Th2-like chemokine levels are increased in allergic children and influenced by maternal immunity during pregnancy

BACKGROUND

The influence of the intra-uterine environment on the immunity and allergy development in the offspring is unclear. We aimed to investigate (i) whether the pregnancy magnifies the Th2 immunity in allergic and non-allergic women, (ii) whether the maternal chemokine levels during pregnancy influenced the offspring's chemokine levels during childhood and (iii) the relationship between circulating Th1/Th2-associated chemokines and allergy in mothers and children.

METHODS

The Th1-associated chemokines CXCL9, CXCL10, CXCL11, and the Th2-associated chemokines CCL17, CCL18 and CCL22 were quantified by Luminex and ELISA in 20 women with and 36 women without allergic symptoms at gestational week (gw) 10-12, 15-16, 25, 35, 39 and 2 and 12 months post-partum and in their children at birth, 6, 12, 24 months and 6 years of age. Total IgE levels were measured using ImmunoCAP Technology.

RESULTS

The levels of the Th2-like chemokines were not magnified by pregnancy. Instead decreased levels were shown during pregnancy (irrespectively of maternal allergy status) as compared to post-partum. In the whole group, the Th1-like chemokine levels were higher at gw 39 than during the first and second trimester and post-partum. Maternal CXCL11, CCL18 and CCL22 levels during and after pregnancy correlated with the corresponding chemokines in the offspring during childhood. Increased CCL22 and decreased CXCL10 levels in the children were associated with sensitisation and increased CCL17 levels with allergic symptoms during childhood. Maternal chemokine levels were not associated with maternal allergic disease.

CONCLUSIONS

Allergic symptoms and sensitisation were associated with decreased Th1- and increased Th2-associated chemokine levels during childhood, indicating a Th2 shift in the allergic children, possibly influenced by the maternal immunity during pregnancy.

Prevalence of childhood eczema and food sensitization in the First Nations reserve of Natuashish, Labrador, Canada

Background

The Mushua Innu of Natuashish, Labrador, Canada seem to have a high rate of childhood eczema. Anecdotally this problem seems to be more common now than 20 years ago. There has been speculation that this could be related to food sensitization that may have arisen coincident with a move away from a traditional Innu diet. We undertook to assess the prevalence and severity of pediatric eczema in Natuashish (population 792), and investigate the level of sensitization to common food antigens.

Methods

Over a three-month period we performed a population survey of all children in the community from the ages of 2–12 inclusive. The one-year prevalence of eczema was assessed using the United Kingdom Working Party’s diagnostic criteria, and graded on the Nottingham Severity Scale. All children with eczema and twice as many age/sex matched controls were offered complete blood counts, total IgE, and food specific IgE levels for egg white, cow’s milk protein and wheat.

Results

One hundred and eighty two (95% of the eligible children) were assessed. Of the 182 children examined eczema was diagnosed in 30 (16.5%) - 22 females and 8 males. The majority of children with eczema (20/30) were classified as being in the moderate and severe category. Of the 22 with eczema and 40 controls who consented to venipuncture all but 3 had IgE levels above the lab's reference range. Food specific antibody assays showed that 32, 23, and 5 percent of children with eczema were sensitized to egg, milk, and wheat respectively. None of the controls were sensitized.

Conclusions

The children of Natuashish, Labrador have a high rate of eczema, much of it graded as moderate or severe. IgE levels were markedly elevated in children with and without eczema, with average values at least ten-fold higher than other populations. There is no evidence of an unusual amount of sensitization to egg, milk or wheat.

Sensitization profile in differential diagnosis: allergic asthma vs. chronic (nonspecific) cough syndrome

BACKGROUND

In the subgroup of children with chronic cough, distinguishing children with allergic asthma from those with non-specific respiratory symptoms is difficult. We have focused on determination of diagnostic efficiency of serum total IgE, sIgE, and skin prick test in differentiation of asthmatic children from children with nonspecific respiratory symptoms.

MATERIAL AND METHODS

A total of 131 children with median age of 7.5 years were enrolled in study and divided into 2 groups; children with allergic asthma (N=71) and children with chronic cough (N=60). Participants underwent the standard allergological examination, including skin prick test and measurement of total IgE, and following 3 allergen-specific IgE antibodies against aeroallergens: Dermatophagoides pteronyssinus, Ambrosia artemisiifolia, and Phleum pratense.

RESULTS

The percentage of patients with elevated level of total and sIgE was higher in children with allergic asthma than in children with chronic cough syndrome (P=0.0001). In children with asthma, sIgE had a better diagnostic value than total IgE. The best diagnostic efficiency of cut-off values for sIgE was shown for Der p sIgE. Skin prick test to all allergens had 78.82% sensitivity and 91.3% specificity in differentiating the 2 tested groups. The highest sensitivity and specificity in skin prick test was proved for Dermatophagoides pteronyssinus.

CONCLUSIONS

The sensitization profile consisting of total IgE, sIgE levels, and SPT clearly distinguishes children with allergic asthma from children with chronic nonspecific cough, but still with overlap. Therefore, diagnosis should always be confirmed by a thorough allergy investigation.

Assessment of Total/Specific IgE Levels Against 7 Inhalant Allergens in Children Aged 3 to 6 Years in Seoul, Korea

PURPOSE

Childhood allergies are a serious problem, as they may lead to lifetime chronic disease. Determination of total and specific IgE levels is known to be a diagnostic tool for allergic sensitization; however, IgE levels are affected by various factors, such as age, sex, ethnicity, and geographic area. Thus, we evaluated the distribution of total and specific serum IgE levels against seven inhalant allergens in preschool children and examined their association with allergic diseases in Seoul, Korea.

METHODS

Total/specific serum IgE determination and skin prick tests for seven common allergens were performed on 509 children aged 3 to 6 years from 16 child care centers in Seoul, Korea. Demographic characteristics were surveyed from parents using a modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. A diagnosis of atopic dermatitis was made by physicians.

RESULTS

The geometric mean of total IgE was 80.48±3.80 kU/L in preschool children. IgE levels were higher in boys (boys, 102.34±3.52 kU/L; girls, 62.37±3.93 kU/L; P<0.001) and atopic subjects (atopic, 158.00±3.35 kU/L; non-atopic, 52.75±3.44 kU/L; P<0.001). An increased prevalence of atopy was associated with a high monthly household income (P=0.004) and higher maternal education level (above university-level education; P=0.009), as well as increased total IgE levels (P=0.036). Physician-diagnosed atopic dermatitis was associated with sensitization to inhalant allergens.

CONCLUSIONS

Total IgE levels were very high as compared with those in previous reports from other countries. The most common sensitized allergen was Dermatophagoides farinae, and the positive response rate peaked at age 3 years and was maintained thereafter, particularly in boys. Specific IgE levels for seven inhalant allergens varied with age in preschool children. Although further investigations are needed with a broad range of ages and various allergens, the distribution of the total and specific serum IgE levels in preschool children might help to serve as a reference value to diagnose atopy.

Analysis of serum total IgE, specific IgE and eosinophils in children with acute and chronic urticaria

BACKGROUND/PURPOSE

Increased IgE and eosinophil levels are frequently observed in cutaneous inflammation and are thought to provoke the occurrence of urticaria. However, the relationship of these factors with the disease duration of urticaria remains unclear. The aim of this study was to compare serum total IgE levels, specific IgE sensitization rates and eosinophil percentages between acute and chronic urticaria in children.

METHODS

A total of 165 patients (104 with acute and 61 with chronic urticaria) from a tertiary referral hospital were enrolled in this study. Serum levels of total IgE, prevalence of sensitization to food and aeroallergens and blood eosinophil percentages were compared by the disease duration of urticaria.

RESULTS

There were no statistical differences in total IgE production, positive sensitization to specific allergens and eosinophil percentages between the patients with acute and chronic urticaria. There is a higher prevalence of sensitization to aeroallergens than food allergens in children with urticaria. In terms of gender, males had significantly higher serum IgE levels than females.

CONCLUSION

Boys potentially have a higher serum IgE expression than girls children with urticaria. IgE levels and eosinophil percentages are not good indicators for a prolonged course of urticaria. The prevalence of sensitization to aeroallergens was significantly higher than that of food allergens in children with urticaria. Routine laboratory analysis for common allergens is not appropriate, and it could be a feasible approach to detect a predilection for atopy when respiratory infections are causative factors of urticaria occurrence.

IFNG genotype and sex interact to influence the risk of childhood asthma

BACKGROUND

Asthma is a complex disease characterized by sex-specific differences in incidence, prevalence, and severity, but little is known about the molecular basis of these sex-based differences.

OBJECTIVE

To investigate the genetic architecture of sex differences in asthma risk, we evaluated (1) associations between polymorphisms in the IFNG gene and childhood-onset asthma in combined and sex-specific samples and (2) interactions between polymorphisms and sex on asthma risk.

METHODS

Main and sex-interaction effects of IFNG genetic diversity on asthma risk and IFN-γ levels were examined in a birth cohort of children at high risk for asthma and allergic diseases. Replication of the genetic association was assessed in an independent sample of asthma cases.

RESULTS

Significant genotype-sex interactions on asthma were observed for 2 IFNG single nucleotide polymorphisms, rs2069727 and rs2430561, which were in strong linkage disequilibrium with each other. In contrast, none of the 10 IFNG single nucleotide polymorphisms showed significant main effects on asthma. The observed genotype-sex interaction on asthma was characterized by nonadditivity; that is, heterozygous boys had the highest risk for asthma, and heterozygous girls had the lowest risk. The interaction effect was robust to other asthma risk factors but was limited to children who experienced wheezing illnesses with viral infections during the first 3 years of life. Genotype-sex interactions were also observed in the IFN-γ response to LPS in the first year of life. Finally, the sex-interaction effect was replicated in an independent population of childhood asthma cases.

CONCLUSIONS

These results provide insight into the genetic basis of sex differences in asthma and highlight the potential importance of interactions among sex, genotype, and environmental factors in asthma pathogenesis.

Early detection of allergic diseases in otorhinolaryngology

Asthmatic diseases have been reported since the ancient world. Hay fever for instance, was described for the first time in the late 18(th) century, and the term "allergy" was introduced about 100 years ago. Today the incidence of allergies is rising; almost one third of the Western population suffers from its side effects. Allergies are some of the most chronic medical complaints, which results in high health expenditures. Therefore, they have a large health and political relevance.Caused by genetic and environmental factors, the group of IgE mediated allergies is large. It consists of e.g. atopic dermatitis, allergic asthma or allergic rhinitis. This paper aims to emphasize the ways of early diagnosis of allergic rhinitis (AR) as AR represents the most important representative of allergic diseases in ENT.

Factors influencing the incidence and prevalence of food allergy

Food allergy is an increasing problem in Europe and elsewhere and severe reactions to food are also becoming more common. As food allergy is usually associated with other forms of allergic sensitisation it is likely that many risk factors are common to all forms of allergy. However the potential severity of the disease and the specific public heath measures required for food allergy make it important to identify the specific risk factors for this condition. Food allergy is unusual in that it often manifests itself very early in life and commonly remits with the development of tolerance. Hypotheses that explain the distribution of food allergy include specific genetic polymorphisms, the nature of the allergens involved and the unique exposure to large quantities of allergen through the gut. Progress has been made in developing more specific and testable hypotheses but the evidence for any of these is still only preliminary. Further collaborative research is required to develop an appropriate public health response to this growing problem.

The allergic sensitization in infants with atopic eczema from different countries

BACKGROUND

No study has compared allergic sensitization patterns in infants with atopic eczema from different countries. The aim of this study was to investigate the patterns of allergic sensitization in a cohort of infants with atopic eczema participating in a multicentre, international study.

METHODS

Two thousand one hundred and eighty-four infants (mean age 17.6 months) with atopic eczema from allergic families were screened in 94 centres in 12 countries to participate in a randomized trial for the early prevention of asthma. Clinical history, Severity Scoring of Atopic Dermatitis Index, measurements for total serum IgE and specific IgE antibodies to eight food and inhalant allergens were entered into a database before randomization to treatment. A history of type of feeding in the first weeks of life and exposure to animals was recorded.

RESULTS

A total of 52.9% of the infants had raised total IgE, and 55.5% were sensitized to at least one allergen. There was a wide difference in the total IgE values and in the sensitization rates to foods and aeroallergens among infants from different countries. The highest prevalence rates of allergen-sensitized infants were found in Australia (83%), the UK (79%) and Italy (76%). Infants from Belgium and Poland consistently had the lowest sensitization rates. In each country, a characteristic pattern of sensitization was found for aeroallergens (house dust mite > cat > grass pollen > Alternaria), but not for food allergens.

CONCLUSIONS

In infants with atopic eczema, there is a wide variation in the pattern of allergic sensitization between countries, and data from one country are not necessarily generalizable to other countries.

ADAM33 genetic polymorphisms and risk of atopic dermatitis among Japanese children

OBJECTIVES

ADAM33, a disintegrin and metalloproteinase 33, gene has been identified as an asthma susceptibility gene. The relationship between single nucleotide polymorphisms (SNPs) in ADAM33 and atopic dermatitis (AD) in Japanese children was examined using case-control design.

METHODS

Seven SNPs of ADAM33 (rs2853209, rs2787094, rs2280091, rs2280090, rs628977, rs597980, and rs528557) were analyzed in 140 AD cases and 258 controls aged 3 years.

RESULTS

Only rs2853209 (T>A) was significantly associated with AD risk. Sex-adjusted odds ratio (OR) for the AA versus the TT genotype was 0.55 (95% confidence interval (CI), 0.30-0.997). Consistent with the results of genotyping analysis, a haplotype carrying rs2853209 A allele was significantly associated with decreased risk of AD compared to all the other haplotypes combined (OR=0.26, 95% CI=0.08-0.69).

CONCLUSION

This is the first study to provide evidence for an association of the ADAM33 polymorphism with AD risk but the strength of this evidence is limited by our small sample size.

Sensitization to inhalant allergens between 4 and 8 years of age is a dynamic process: results from the BAMSE birth cohort

BACKGROUND

There is limited knowledge of the development of IgE-antibody levels over time in childhood, with respect to persistency and co-sensitization to specific inhalant allergens.

METHODS

Data from 2033 children participating in the BAMSE birth cohort was used. Background factors and clinical parameters were obtained and IgE antibody (ab) levels to eight common airborne allergens were measured (>or=0.35 kU(A)/L) when the children were 4 and 8 years of age.

RESULTS

Between 4 and 8 years the proportion of children sensitized to any of the inhalant allergens tested increased from 15% to 25%. At 4 years IgE-ab to birch and cat dominated, whereas at the age of 8, there was a considerable increase in the proportion of sensitization to timothy and dog. Except for mites and moulds, IgE-ab levels to all aeroallergens increased significantly between 4 and 8 years among those already sensitized at 4. Transient sensitization to inhalant allergen was uncommon. Furthermore, sensitization to birch pollen at 4 years increased the risk for becoming sensitized to timothy, cat and dog later in life. Such an association was not observed among those sensitized primarily to animal dander.

CONCLUSIONS

There is a prominent process of sensitization at pre-school age to inhalant allergens, and in Northern Europe sensitization to birch pollen early in life seems to be important for this process. Such a process has a probable impact on the development of allergic disease in the growing child.

Are age-specific high serum IgE levels associated with worse symptomatology in children with atopic dermatitis?

BACKGROUND

Atopic dermatitis (AD) is a distressing disease associated with excoriations, pruritus, sleep disturbance, and elevation of serum total immunoglobulin E (IgE) levels.

OBJECTIVE

To evaluate whether serum IgE levels correlate with the symptomatology and plasma chemokine levels in children with AD.

METHODS

AD patients aged younger than 18 years were recruited from the pediatric dermatology clinic of a university teaching hospital, and the AD severity was evaluated using the SCORing Atopic Dermatitis (SCORAD) index. Concentrations of serum total IgE, eosinophil count, and plasma AD-associated chemokines [cutaneous T-cell-attracting cytokine (CTACK), thymus and activation-regulated chemokine (TARC)] were measured.

RESULTS

One hundred and seventeen Chinese children with AD (64 boys and 53 girls), with an age (mean +/- standard deviation) of 10.7 +/- 4.4 years, were recruited. Their overall SCORAD index (mean +/- standard deviation) was 51.1 +/- 22.8. The total serum IgE level divided by the age-specific upper limit (AE) correlated well with the extent and intensity of AD, except for oozing/crusting, which was significant only in males. There was a significant correlation between AE and pruritus or sleep loss only in females. Levels of IgE, CTACK, and TARC, and eosinophil count, differed significantly between patients with mild, moderate, and severe disease. AE correlated well with TARC (r = 0.50, P < 0.001) and eosinophil count (r = 0.41, P < 0.001), but not with CTACK (r = 0.11, P = 0.270). The prediction of moderate to severe eczema by AE gave an area under the receiver-operating characteristic curve of 0.76 (95% confidence interval, 0.65-0.86; P = 0.004). An optimum positive predictive value of 94.2% was achieved with a cut-off point of AE of 2.95, sensitivity of 75.0%, and specificity of 66.7%.

CONCLUSION

AE correlates significantly with various objective clinical scores and chemokine markers of AD, and is a useful indicator for predicting moderate to severe AD in children.

Impact of gender on asthma in childhood and adolescence: a GA2LEN review

A number of studies have shown gender differences in the prevalence of wheeze and asthma. The aim of this review was to examine published results on gender differences in childhood and adolescent asthma incidence and prevalence, define current concepts and to identify new research needs. A Medline search was performed with the search words (gender OR sex) AND (child OR childhood OR adolescence) AND (asthma). Articles that reported on absence or presence of gender differences in asthma were included and reviewed, and cross-references were checked. Boys are consistently reported to have more prevalent wheeze and asthma than girls. In adolescence, the pattern changes and onset of wheeze is more prevalent in females than males. Asthma, after childhood, is more severe in females than in males, and is underdiagnosed and undertreated in female adolescents. Possible explanations for this switch around puberty in the gender susceptibility to develop asthma include hormonal changes and gender-specific differences in environmental exposures. This aspect needs consideration of the doctors and allergists who diagnose and treat asthmatic individuals. In conclusion, sex hormones are likely to play an important role in the development and outcome of the allergic immune response and asthma in particular. By obtaining functional data from appropriate models, the exact underlying mechanisms can be unravelled. To examine the effect of gender-specific differences in environmental exposures and changes of asthma prevalence and severity in puberty, larger populations may need to be investigated.

Influence of early day-care exposure on total IgE levels through age 3 years

BACKGROUND

Early day care is inversely associated with asthma and atopy in later childhood, but its association with early immunologic markers of asthma risk is not known.

OBJECTIVE

We sought to assess the relation of day care by 3 months to total IgE levels through age 3 years.

METHODS

Day care was assessed prospectively among 362 nonselected infants enrolled in the Infant Immune Study. Children were categorized based on day-care status by 3 months of age as follows: no day care, day care inside the home with other children, day care outside the home with no other children, or day care outside the home with other children. Total IgE levels were measured in blood obtained at 3, 12, 24, and 36 months. Relations between day care and IgE levels were assessed at each age and longitudinally, with stratification by maternal asthma and atopy.

RESULTS

Day care by 3 months was associated with decreased IgE levels through age 3 years (coefficient: -0.19 log IU/mL, P = .001). The greatest effect was evident for children cared for outside the home. Stratified analyses indicated that the relation existed primarily among children who had atopic or asthmatic mothers. Day-care entry after 3 months showed no relation with IgE levels.

CONCLUSION

Day-care attendance by 3 months is associated with decreased total IgE levels in the first 3 years of life in children of mothers who are atopic, asthmatic, or both.

CLINICAL IMPLICATIONS

Early day-care exposure can reduce IgE levels, which in turn might reflect a reduced risk of allergic disease in predisposed children.

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.

Preventive and curative effects of probiotics in atopic patients

Normally, the transport of allergens through the intestinal epithelia to the blood is limited. It is hypothesised that if these compounds arrive in the blood circulation, they must percolate through the epithelial cell layer. Thus, food allergy (and thus atopic eczema) implies an increased intercellular leakage of the gut wall. Such increased intercellular leakage is thought to be caused by a slightly changed cellular morphology due to a slight cytopathologic effect because of both a limited decay of the cytoskeleton and a slightly reduced turgor. These events may be due to a reduced production of intracellular metabolic energy in the epithelial cells due to an increased concentration of familiar, frequently occurring, potentially toxic bacterial metabolites, i.e., d-lactic acid and/or ethanol. In this hypothesis we suggest that adequate probiotics can (i) prevent the increased characteristic intestinal permeability of children with atopic eczema and food allergy, (ii) can thus prevent the uptake of allergens, and (iii) finally can prevent the expression of the atopic constitution. The use of adequate probiotic lactobacilli, i.e., homolactic and/or facultatively heterolactic l-lactic acid-producing lactobacilli, reduces the intestinal amounts of the bacterial, toxic metabolites, d-lactic acid and ethanol by fermentative production of merely the non-toxic l-lactic acid from glucose. Thus, it is thought that beneficial probiotic micro-organisms promote gut barrier function and both undo and prevent unfavourable intestinal micro-ecological alterations in allergic individuals.

Variability of total serum immunoglobulin E levels from birth to the age of 10 years. A prospective evaluation in a large birth cohort (German Multicenter Allergy Study)

BACKGROUND

Many environmental factors influence the concentration of total serum IgE (tIgE); however, tIgE synthesis is believed to be under strong genetic influence. Multiple genetic studies on tIgE regulation have been performed. For these population-based studies tIgE was commonly determined at one time-point, assuming that tIgE phenotypes (adjusted for age and gender) are stable over time.

OBJECTIVE

We assessed correlations of tIgE levels from birth to the age of 10 years in the birth cohort MAS (Multicenter Allergy Study; n=1314).

MATERIALS AND METHODS

We determined cord-blood IgE levels, total and specific IgE at the age of 1, 2, 3, 5, 6, 7, and 10 years. Spearman correlation coefficients were calculated for tIgE at different time-points. All analyses were performed in the entire cohort, adjusted for gender, as well as in non-atopic children only.

RESULTS

tIgE percentiles increased steadily from birth to the age of 10 years with higher values for boys than for girls at each time-point. tIgE values from birth to 3 years of age correlated poorly with tIgE levels at 10 years (r<0.5). However, good correlations (r>0.8) were observed for tIgE concentrations at 6, 7 and 10 years. The same results were observed when the analyses were limited to non-atopic children.

CONCLUSION

In childhood, tIgE levels underlie remarkable variation over time even in the absence of atopy. For cross-sectional population-based genetic and epidemiologic studies, tIgE values of children <5 years should be interpreted with caution since these values correlate poorly with tIgE levels later in life.

Prevalence of allergy symptoms and total IgE in a New York City cohort and their association with birth order

BACKGROUND

An inverse association between birth order and allergic disease has been widely observed, but has not been examined in the high asthma prevalence, inner-city populations of the United States. As part of an ongoing prospective birth cohort study, the prevalence of early phenotypes of asthma and/or allergy was compared with those reported in other studies, and the association with birth order was evaluated.

METHODS

Children of Dominican and African-American mothers living in Northern Manhattan underwent detailed periodic questionnaires. Total IgE from the mothers (n = 321) and the children at birth (n = 291) and at ages 24 (n = 244) and 36 (n = 155) months was measured. The association between birth order and allergy symptoms was evaluated at 12 (n = 350), 24 (n = 290) and 36 (n = 247) months.

RESULTS

Total serum IgE was detectable (>0.5 IU/ml) in 35% of the children's cord blood and averaged 15 and 21 IU/ml at ages 24 and 36 months, respectively. They were not significantly different at any age between children with and without older siblings. Additionally, at these ages, there were no consistent associations between birth order and either wheeze, itchy eyes or eczema.

CONCLUSIONS

Despite a substantially higher prevalence of asthma in the Northern Manhattan community compared with other areas, total IgE levels at ages 24 and 36 months, but not cord blood, are similar to those reported in other areas of the world. In this community, results at this age do not support a protective effect of higher birth order.

Dietary modification of atopic disease: Use of probiotics in the prevention of atopic dermatitis

The increased prevalence of atopic diseases, atopic dermatitis, allergic rhinitis, and asthma has been described as an epidemic. New approaches in the fight against allergic diseases are called for, the target being the persistence of the atopic T helper 2-skewed immune responder pattern beyond infancy. Atopic dermatitis, the earliest of these conditions, might act as a portal for the development of IgE-mediated atopic manifestations. Abundant evidence implies that specific strains selected from the healthy gut microbiota exhibit powerful antipathogenic and anti-inflammatory capabilities, and several targets for the probiotic approach have emerged in atopic dermatitis: degradation/structural modification of enteral antigens, normalization of the properties of aberrant indigenous microbiota and of gut barrier functions, regulation of the secretion of inflammatory mediators, and promotion of the development of the immune system. Better understanding of the effects of different probiotic strains and deeper insight into the mechanisms of the heterogeneous manifestations of atopic disease are needed for the validation of specific strains carrying anti-allergic potential.

Lack of detectable alterations in immune responses during sublingual immunotherapy in children with seasonal allergic rhinoconjunctivitis to grass pollen

BACKGROUND

Recent work indicates that subcutaneous specific immunotherapy induces specific T-cell anergy, a shift in the TH1/TH2 ratio, and antibody production in favor of IgG4. There are few data on sublingual immunotherapy (SLIT), especially in children.

METHODS

We assessed the proliferation of peripheral blood mononuclear cells ((3)H-thymidine incorporation) and secretion of interleukin (IL)-4, interferon (IFN)gamma and IL-5 (ELISA) after in vitro stimulation with allergen or phytohemagglutinin (PHA) in 29 children with allergic rhinoconjunctivitis receiving SLIT with grass pollen before, and after 1 and 2 years of treatment in a multicenter placebo-controlled study on the efficacy of the treatment. Further, non-specific intracellular production of IL-4, IL-13, IFNgamma, IL-2, IL-10 and IL-5 (FACS) and serum total and specific IgE and IgG4 (ELISA) were analyzed.

RESULTS

Proliferation and IL-4 and IL-5 secretion after stimulation with allergen or PHA did not differ between the groups. In addition, we observed no effect of SLIT on intracellular cytokine production. IFNgamma secretion after allergen coculture was comparable between the groups. Following PHA stimulation, IFNgamma secretion was significantly higher in the SLIT group after 1 year, and a trend was observable already before and after 2 years of treatment, probably due to the inhomogeneity in the groups despite randomization (for age and asthma). No significant changes were observed for sIgE/sIgG4 ratios over time either in or between the groups.

CONCLUSION

During 2 years of SLIT in children with a positive effect on rescue medication use, we observed no significant effects on in vitro T-cell immune responses or immunoglobulins. So far, pediatric studies demonstrating stable effects of SLIT on such reactions are missing, probably due to limited effects of SLIT on systemic immunologic reactions.

Does the severity of atopic dermatitis correlate with serum IgE levels?

Recent studies suggest an association between atopic phenotypes and serum IgE levels. In contrast to asthma, this association has not been proven for atopic dermatitis. For 345 children (mean age 2.9 years), we investigated a correlation of the severity of eczema (defined by SCORAD score) and serum IgE levels. Additionally, the data was analyzed for differences between children with high and low SCORAD quartile. Parameters such as genetic background, the prevalence of other atopic phenotypes such as bronchial asthma, allergic rhinoconjunctivitis, and allergic sensitization were recorded. Our results indicate a significant correlation between SCORAD and serum IgE levels (R = 0.31, p < 0.001), but the standard deviation was large. Children with atopic dermatitis showed a high prevalence of sensitization to foods independent of the IgE levels; children with high SCORAD levels showed a sensitization to aeroallergens significantly more often (p < 0.02). No differences were found in prevalences of atopic family background, or a number of additional atopic symptoms such as asthma and allergic rhinoconjunctivitis. These results suggest that serum IgE levels seem to correlate with the degree of eczema. Children with severe atopic dermatitis and high IgE levels are at risk for sensitization to food allergens and aeroallergens.

Prenatal prediction of infant atopy by maternal but not paternal total IgE levels

BACKGROUND

The atopic history of parents has long been used to predict infant atopy. However, bias from questionnaires of allergic history are also frequently suspected, because a large number of vasomotor rhinitis, intrinsic asthma, and seborrheic dermatitis cases are probably misinterpreted to be atopic diseases.

OBJECTIVE

We attempted to identify a risk factor other than parental atopic history to predict elevated infant IgE levels and infant atopy.

METHODS

A total of 655 core families were prenatally recruited, and finally 545 families completed the study for the prospective analysis of infant atopy at 6 months of age. Atopic history and blood samples of parents were collected in the third trimester during pregnancy. Cord blood (CB) was collected immediately after birth. Infant blood samples and history of infant eczema were collected in the 6-month physical checkup clinic. Blood total IgE and specific IgE levels were determined by use of the Pharmacia CAP system.

RESULTS

In univariate analysis, maternal, but not paternal, atopic history correlated with elevated CB IgE levels and the occurrence of infant eczema. Elevated maternal, but not paternal, total IgE levels (>150 KU/L) significantly correlated with increases of CB IgE levels (median, 0.54 vs 0.17 KU/L, P <.001), infant IgE levels (log-transformed mean values, 1.32 +/- 0.51 vs 1.13 +/- 0.51 KU/L, P <.001), and infant eczema (P =.008). Multivariate logistical regression analysis, however, showed that only maternal total IgE levels correlated with CB and infant IgE levels and the development of infant eczema.

CONCLUSIONS

The maternal, but not paternal, total IgE level correlates with elevated infant IgE levels and infant atopy. This provides a high specificity (83%) and a sensitivity of 34% for prediction of infant atopy. This suggests that maternal factors, placental factors, or both have an impact on perinatal allergic sensitization.

Prebiotics in infant milk formulas: new perspectives

In recent years it has become accepted that healthy human intestinal microflora may play an important part in priming the infants' systemic and mucosal immunity. Dietary modulation of the gut microbiota is a topical area of nutritional sciences and the main focus of many current functional foods such as non-digestible oligosaccharides (NDOs). Fructo-oligosaccharides (FOS) and trans-beta-galacto-oligosaccharides (TOS) have been claimed to benefit the health of the colon by selectively stimulating the growth of bifidobacteria and lactobacilli (prebiotic effect). It could be of clinical interest to manipulate colonic flora because it is supposed that specific bacteria in the gut microbial microflora could promote potentially antiallergenic processes and play a key part in atopic disease prevention. Supporting this view is the finding that analysis of the composition of the intestinal bacterial populations showed different microbial patterns between healthy and allergic individuals. Assuming that non-digestible TOS and FOS can affect the intestinal ecosystem beneficially, the opportunity for gut flora manipulation arises in bottle-fed infants. New preterm and term infant milk formulas, supplemented with a mixture of TOS and FOS as prebiotic ingredients induced a significantly higher colonization of bifidobacteria and lactobacilli. In the future, selective manipulation of the intestinal microbiota might be an approach to novel prophylactic and therapeutic intervention strategies of atopy, by redirecting allergic Th-2 responses in favour of Th-1 responses.

Extraordinarily high serum IgE levels and consequences for atopic phenotypes

BACKGROUND

IgE plays a central role in allergic diseases. Recent studies have postulated an association between serum IgE levels and bronchial asthma.

OBJECTIVE

To examine the differences of atopic phenotypes in a group of individuals with extraordinarily high serum IgE levels (>10,000 kU/L) compared with children with moderately elevated IgE levels (400-1,000 kU/L).

METHODS

We investigated 20 children with serum IgE levels greater than 10,000 kU/L and compared them with 56 age-matched children with serum IgE levels of 400 to 1,000 kU/L regarding prevalences of atopic dermatitis, bronchial asthma, allergic rhinoconjunctivitis, allergic sensitization, and history of anaphylaxis.

RESULTS

The mean eczema severity score as determined by the Severity Scoring of Atopic Dermatitis Index was 56 vs 18 (P < 0.003), and anaphylactic reactions were reported in 20% of the group with very high serum IgE levels vs 7% in the group with moderate levels (P < 0.02). Sensitization to both aeroallergens and food allergens was detected in 80% of the group with very high serum IgE levels vs 32% of the group with moderate levels (P < 0.001).

CONCLUSIONS

Our results indicate that children with very high serum IgE levels are at risk for anaphylactic reactions and more severe atopic dermatitis.

Therapeutic implications of sex differences in asthma and atopy

Clear sex differences exist in asthma and atopy with a preponderance of boys before puberty. There is a reversal of this sex ratio during puberty with girls having more asthma and atopy throughout the reproductive years. Elucidating the reasons for the switch in the sex ratio should provide fresh insights into asthma and atopy with a real prospect of novel therapies for these troublesome diseases. The challenge is to match the epidemiology and physiology with the accumulating scientific knowledge on gender differences in immune responses. Hormonal changes have been implicated in the reversal of the sex ratio. Testosterone is an immunosuppressant and is likely to be protective, while female sex steroids are proinflammatory and will increase the susceptibility to atopy. Modified so as to be non-virilising/feminising, sex steroids could therefore play a useful part in modulating the immunological and inflammatory processes that underlie asthma and other allergic disorders, complementing the currently used glucocorticoid derived steroids.

Breast milk fatty acids, eicosanoids, and cytokines in mothers with and without allergic disease

Allergic disease (AD), including atopic eczema, asthma, allergic rhinitis, and food allergy, is characterized by an imbalance between cytokines produced by distinct T-helper cell subtypes. Whether this imbalance can be transferred from mother to breast milk remains to be established. The objective was to investigate the concentrations and interactions of nutritional and inflammatory factors in breast milk. Breast milk samples were collected from mothers with AD (n = 43) and without AD (n = 51). The concentrations of transforming growth factor (TGF)-beta2, tumor necrosis factor-alpha, IL-4, IL-10, prostaglandin E2, and cysteinyl leukotrienes were measured by immunoassays and fatty acid composition by gas chromatography. Mothers with AD had a lower concentration of TGF-beta2 in breast milk [median (interquartile range), 420 (278-701) ng/L] compared with those without AD [539 (378-1108) ng/L; p = 0.003], whereas other cytokines, prostaglandin E2, and cysteinyl leukotriene concentrations or fatty acid composition were not significantly different between the groups. The breast milk inflammatory factors and fatty acid composition were shown to be related. A positive association was observed between TGF-beta2 and the proportion of polyunsaturated fatty acids (p = 0.038) and a negative association between TGF-beta2 and the proportion of saturated fatty acids (p = 0.029) in breast milk. The reduced TGF-beta2 concentration in the breast milk of mothers with AD may interfere with the development of the mucosal immune system of the breast-fed infant. The observed associations between nutritional and inflammatory factors in breast milk suggest that it may be possible to influence the immunologic properties of breast milk by dietary intervention of the mother.

Inventing probiotic functional foods for patients with allergic disease

OBJECTIVE

The primary objective of this review is to discuss the rationale for and applicability of probiotics as part of the nutritional approach to the prevention and management of allergic disease.

DATA SOURCES

This review represents a synthesis of recent literature published in the fields of probiotics, nutrition, and allergic disease.

STUDY SELECTION

The expert opinions of the authors were used to select the relevant data for the review.

RESULTS

The hygiene hypothesis suggests that allergic disease may arise from a lack of counterbalancing microbial exposure at an early age. Thus, the initial compositional development of gut microbiota is considered a key determinant in the development of both the immune responder phenotype and the normal gut barrier functions. A wide range of data documents the specific actions of selected probiotics. The regulatory role of probiotics in allergic disease has been demonstrated as improving the clinical course or preventing the development of atopic eczema in infants given a probiotic-supplemented diet. In addition, certain types of fatty acids and antioxidants have been proposed for protective effects against the development of allergy and to diminish the inflammatory response in allergic disease.

CONCLUSIONS

The increase in the prevalence of allergic disease during the past decades is likely to be explained by changes in the environment, including reduced microbial exposure and altered food consumption. Scientifically composed functional foods containing probiotics and other functional components offer a nutritional strategy for both the prevention and the management of allergic disease. Further research is needed to characterize the gut microbiota and to clarify the mechanisms of action that control specific physiologic processes not only in the evolution of allergic disease in at-risk populations but also in the management of allergic diseases.

Polyclonal and allergen-induced cytokine responses in children with elevated immunoglobulin E but no atopic disease

BACKGROUND

Reduced Th1 and elevated Th2 cytokine responses are considered to be a principal mechanism in the generation of the inflammation leading to the manifestations of atopic disease in the skin of atopic dermatitis and in the airways of asthma. If reduced Th1 and elevated Th2 responses are principal determinants of the manifestation of atopic disease it might be expected that subjects with established disease would exhibit differences in their cytokine profiles as compared with atopic patients without clinical disease.

OBJECTIVE

To determine whether asymptomatic atopic children exhibit a cytokine imbalance similar to that seen in patients with established atopic disease or if they behave like non-atopic controls. Cytokine responses in a group of children with elevated IgE but no clinical manifestations of disease, atopic children with established disease and non-atopic controls were compared.

METHODS

We examined allergen-induced (house dust mite, HDM, rye grass pollen and RYE) cytokine responses in parallel with polyclonal (staphylococcal enterotoxin B, SEB) cytokine responses in a group of children with elevated serum IgE levels without current or past evidence of atopic disease (median age 6.6 years) and compared these with a non-atopic control group (median age 6.5 years) and a group of children with atopic disease (median age 6.7 years).

RESULTS

Symptomatic atopic children had reduced SEB-induced IFN-gamma and increased SEB-induced IL-4 and IL-5 as compared with non-atopic controls. In contrast, SEB-induced IFN-gamma, IL-4 and IL-5 production in asymptomatic atopics was not significantly different from the non-atopic control subjects. Allergen-induced Th1 (IFN-gamma) and Th2 (IL-5 and IL-13) cytokine production was increased in both symptomatic atopics and asymptomatic atopics when compared with non-atopic controls.

CONCLUSION

The defect in polyclonally induced IFN-gamma production was associated with the clinical manifestation of atopic disease but not the atopic stateper se. This suggests that the global reduction in IFN-gamma is the key determinant of the development of overt atopic disease. In contrast, elevated allergen-induced Th2 cytokine responses in children related to the atopic state per se irrespective of the presence of clinical atopic disease.

How should a birth cohort study be organised? Experience from the German MAS cohort study

Birth cohort studies offer the opportunity to study average risks, rates and occurrence times of disease longitudinally from birth. The effect of genetic and environmental factors and their interactions can be studied. Furthermore, quantity and duration of exposure to environmental agents can be evaluated prospectively. However, prospective birth cohort studies are expensive, labour intensive and take many years to complete. Loss of subjects over time as well as recall bias complicate the interpretation of observations. This paper summarises the potential pitfalls of such studies and discusses the experience of the German Multicentre Allergy Study (MAS), which began in 1990 in five German cities and included 1314 newborns for the study of the natural course of atopic diseases.

Mode of delivery and asthma -- is there a connection?

Genetic factors cannot explain the recent rapid increase in the incidence of atopic diseases. The phenomenon has been explained by environmental factors, and there are data for and against the hypothesis that a decline in the pressure of microbial stimulation early in life could be behind the allergy epidemic. Changes have also occurred in maternity care, among them a rise in the caesarean section rate, which could diminish initial microbial exposure and thereby alter T helper 1 cell/T helper-2 cell development and affect the risk of developing atopy. In this study, we sought to establish whether mode of delivery does influence the development of atopic asthma. Finnish 1987 Medical Birth Register (n = 59,927 live births) information was linked between several national health registers to obtain information on asthma and mode of delivery in children registered. The data were adjusted for maternal age, previous deliveries, child's sex, and birth size. Atopy was evaluated in the second study (Turku Birth Cohort), which involved 219 children born by vaginal delivery (n = 106) or caesarean section (n = 113); history of atopic symptoms was established by questionnaire and a clinical examination was conducted, including skin prick testing and determination of total and allergen-specific IgE in serum. The register study showed the cumulative incidence of asthma at the age of seven to be significantly higher in children born by caesarean section (4.2%) than in those vaginally delivered (3.3%), the adjusted odds ratio (OR) for confounding variables being 1.21 (1.08-1.36), p < 0.01. In the second study, significantly more positive allergy tests were reported in questionnaires in the caesarean (22%) than in the vaginal delivery group (11%), OR 2.22 (1.06-4.64), p < 0.01, and a trend toward more positive skin prick reactions was documented at clinical examination; 41% versus 29%, OR 1.31 (0.65-2.65), p = 0.11. In conclusion, these results suggest that caesarean section delivery may be associated with an increased prevalence of atopic asthma.

Breast milk--immunomodulatory signals against allergic diseases

Breastfeeding holds a key position with regard to the increasing burden of allergic diseases in the industrialized countries. Not only does it provide the infant with nutrients for growth and development, it also confers immunological protection during a critical period in life, when the infant's own defense mechanisms are immature. A delicate balance of stimulatory, even inflammatory, maturational signals, together with a myriad of anti-inflammatory compounds, is transferred from mother to infant via breastfeeding. Breastfeeding mothers, however, do not constitute a uniform group. The composition of breast milk shows marked individual variation and so, consequently, does the success of breastfeeding in reducing the risk of disease. Recent clinical studies indicate that the potential of breastfeeding to counteract allergic disease may be promoted by dietary means. While uncoordinated elimination diets result in a risk of general nutritional inadequacy or deficiency of essential single nutrients, a balanced diet following current dietary recommendations, specifically containing fresh fruits and vegetables (antioxidants) and fat of predominantly vegetable origin, may be associated with a lower incidence of atopy in the infant. As early nutrition appears to program the subsequent health of the child, the importance of the maternal dietary composition during breastfeeding should be emphasized. In future, an improved understanding of the mechanisms of this programming may offer specific therapeutic modalities for the prevention of allergic disease.