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PubMed2004

A review of the effects of breastfeeding on respiratory infections, atopy, and childhood asthma.

The etiology of childhood asthma is not fully understood. Early exposure to certain respiratory infections may be protective for atopy and/or asthma whereas some infections have been suggested to exert the opposite effects. Wheezing lower respiratory illness (LRI) in the first year of life and atopy are independently associated with increased risk for current asthma in childhood and their effects are mediated via different causal pathways. These risk factors are multiplicative when they operate concommitantly within individual children. Exclusive breastfeeding protects against asthma via effects on both these pathways, as well as through other as yet undefined mechanisms. Furthermore, exclusive breastfeeding may protect against asthma and may reduce the incidence of lower respiratory illness, especially respiratory syncytial virus (RSV). We have previously demonstrated a protective effect of exclusive breastfeeding on asthmatic traits in children. The aim of this review was to clarify this protective association from intermediate associations with respiratory infections, atopy, or through other facets of breastfeeding. The bioactivity of breast milk and subsequent pathways that may act upon the development of asthma in children are explored.

Asthma↗
PubMed2002

Identification of the autoantigen SART-1 as a candidate gene for the development of atopy.

The possibility that immune responses to autoantigens may contribute to the development of atopic disease has been largely ignored. In this paper, we describe the chromosomal localization of the gene for squamous cell carcinoma-associated reactive antigen for cytotoxic T cells (SART-1). The SART-1 gene localized to a region of 11q12-13 showing strong linkage to atopy in previous studies. Further analysis of this gene revealed the presence of at least 20 exons of varying lengths and four novel single-nucleotide polymorphisms, one of which resulted in an amino acid substitution. Association analysis in families recruited on the basis of affected sib pairs for asthma reveal significant association for both coding region polymorphisms with atopy. We therefore hypothesize that polymorphic variation within the SART-1 gene may account for individuals developing atopy.

Alleles↗
PubMed1997

Socioeconomic status, number of siblings, and respiratory infections in early life as determinants of atopy in children.

Asthma and allergic disorders have been on the increase in recent decades, especially among children living in affluent countries; some aspects of the "Western" way of life may explain this trend. We evaluated the relation of aeroallergen skin test reactivity with socioeconomic status, number of siblings, and respiratory infections in early life. We examined a total of 2,226 schoolchildren, ages 7-11 years, in three areas of Lazio, Italy. Skin prick tests were performed to assess atopic status, and self-administered questionnaires were completed by the parents. The prevalence of prick test positivity was greater among children whose fathers were in the highest educational level than among those in the lowest [prevalence ratio (PR) = 1.58; 95% confidence interval (CI) = 1.21-2.06]. There was also a lower prevalence of atopy among larger sibships (PR = 0.38 for subjects with four or more siblings vs those without siblings; 95% CI = 0.14-0.99). A history of bronchitis or bronchiolitis before age 2 years was weakly associated with an increased risk of atopy, whereas a history of pertussis or pneumonia was not. Both the effect of father's education and the influence of larger sibship size remained when we adjusted for several potential confounding factors, including respiratory infections in early life. We infer that higher socioeconomic status and lower sibling number are determinants of atopy in this Italian population. Protection arising from early severe respiratory infections does not explain this association, although we cannot exclude a role for other viral infections.

Age of Onset↗
PubMed2002

Do animals on the farm and in the home reduce the risk of pediatric atopy?

Recent evidence suggests that proximity to pets and farm animals early in life may decrease the risk of developing atopy. Studies investigating the etiology of atopy and asthma have been especially challenging due to difficulties in ascertaining and classifying incident cases. Nevertheless, cross-sectional and cohort studies described in this paper reported across various populations, among children and adults, tended to demonstrate inverse associations between the presence of indoor cats and dogs or frequent exposure to livestock during the first years of life and sensitization to pet and pollen allergens, hay fever, and to a lesser degree, asthma. The biological mechanisms of this protection is unknown, as are the factors associated with pet keeping and livestock farming that may play a role. In the meantime, it appears that counseling prospective parents that avoidance of exposure to animals in the first years of life will prevent atopy may not be sage advice.

Adult↗
PubMed2002

Evolving role of the atopy patch test in the diagnosis of food allergy.

The atopy patch test has developed into a valuable additional tool in the diagnostic work-up of food allergy in infants and children with atopic dermatitis. A positive atopy patch test may help to prevent imposing restrictive and unnecessary diets after misjudging late reactions by clinical assessment alone. Furthermore, the combination of positive atopy patch tests together with defined levels of specific IgE makes double-blind, placebo-controlled food challenges superfluous in some cases. However, several open questions indicate the need for further studies.

Child Welfare↗
PubMed2003

The relationships between atopy, rhinitis and asthma: pathophysiological considerations.

PURPOSE OF REVIEW: A close relationship has been described between atopy, allergic rhinitis and asthma. The purpose of this work was to review recent data that have become available on the interactions between these conditions and the ways in which they influence one another. RECENT FINDINGS: Recent findings support previous observations suggesting that atopic dermatitis and rhinitis often accompany or precede the development of asthma. Further data support the notion that early-life exposure to domestic animals, a farming environment, passive smoking, and being raised in a large family, may be protective against the development of atopy and/or allergic diseases, although this seems modulated by genetic factors. Furthermore, the appearance of house-dust-mite-specific immunoglobulin E antibodies in early childhood has been identified as a major risk factor for the development of asthma in children with atopic dermatitis; and the association between sensitization to specific allergens and airway hyperresponsiveness was reported to be the strongest for indoor allergens such as house-dust-mite and cat. Allergen exposure can increase airway responsiveness in non-asthmatic subjects with allergic rhinitis and is associated with an increase in markers of lower airway inflammation, particularly with indoor allergens. Furthermore, nasal allergen provocation can induce bronchial inflammation and vice versa, suggesting close interrelations between upper and lower airways. SUMMARY: In summary, the recent observations on the relationships between atopy, rhinitis and asthma support the hypothesis of a unique systemic condition with variable manifestations, which may develop following an imbalance between T helper cell types 1 and 2 lymphocyte populations. The latter may be influenced by environmental exposure in early life. Upper- and lower-airway inflammatory events influence each other, supporting the concept of 'united airways'. Further studies should look at the relationships between these conditions to identify individuals at high-risk of developing them and develop strategies to possibly prevent their onset.

Adult↗
PubMed1978

Atopy and bronchial reactivity in Australian and Melanesian populations.

In order to compare the prevalence of atopy and bronchial hyperreactivity among Papua New Guinian (P.N.G.) and Australian populations, skin prick tests and methacholine bronchial challenge tests were performed. A civilian and an army population from each country were examined and those with past or present asthma, recent respiratory tract infection and chronic lung disease were excluded. No statistical difference in the prevalence of atopy was found between the four populations. In the P.N.G. population 40 and 49%, and in the Australian population 27 and 39%, were found to be atopic, without symptoms of past or present allergic disease. The house dust mites were the commonest allergens in all populations. In response to methacholine (0.3 mg), only 6% of subjects had falls in 1 sec forced expiratory volume (FEV1) of more than 12% (upper limit of normal range) and only two were in the asthmatic range. There was no correlation between the degree of bronchial hyperreactivity and atopic status; however, the degree of bronchial hyperreactivity was slightly greater in the New Guinea civilian than in the Australian civilian population. In the absence of asthma, atopic status does not appear to cause increased bronchial reactivity, suggesting that some factor other than atopy must be present for the development of bronchial hyperreactivity characteristic of asthma.

Adolescent↗
PubMed1981

Atopy and cystic fibrosis. A study of CF sibling pairs and their families.

We have investigated the prevalence of atopy within families of cystic fibrosis (CF) patients and compared its frequence in CF patients, their parents and their non-CF siblings. By studying families with two CF patients it was also possible to evaluate the factors influencing the development of atopy in one CF patient relative to the other patient within the same family. A significant correlation with age (P less than 0.001) for skin test positivity to common allergens within CF sibling pairs was observed. In 14/18 families studied, only the older CF patient was atopic. The presence of atopy in CF patients was independent of the atopic status of their parents.

Adolescent↗
PubMed1988

An epidemiological study of atopy in children.

A sample of 930 children, between 9 years and 15 years old from six Italian towns, were studied. Their family history of allergy, personal allergy and medical history, current allergy symptoms, exposure to environmental allergens, feeding as infants, and their parents' occupations were recorded. They were skin-prick tested (SPT) with a range of common allergens. A subject was defined as atopic if at least one SPT caused a weal greater than 3 mm diameter. The association between the recorded information and atopy was investigated by logistic multiple regression. Atopy was positively associated with: high density housing; medium or high exposure to environmental allergens; a history of rhinitis, asthma or atopic eczema; male gender; and a history of breastfeeding. It was independent of infectious diseases, vaccinations and operations, social class and family history. Thus, there was no evidence of a genetic factor in atopy, other than sex.

Adolescent↗
PubMed1992

Genetic analysis of atopy in three large kindreds: no evidence of linkage to D11S97.

Both genetic and environmental influences have been implicated in the pathogenesis of atopic disease. A recent report suggested that a major gene providing susceptibility to atopy was transmitted in a pattern consistent with autosomal dominant inheritance and evidence was presented that places the disease locus near the D11S97 marker on human chromosome 11q. In this report, we present three large, highly characterized pedigrees in which atopy is transmitted in a pattern consistent with autosomal dominant inheritance. Genotypes at the D11S97 and HLA loci were evaluated using both lod score and sib pair methods of analysis. In these pedigrees, we reject close moderate linkage (up to 10 cM) of atopy with both D11S97 and HLA.

Genetic Linkage↗
PubMed1993

Atopy in childhood. II. Relationship to airway responsiveness, hay fever and asthma.

While airway hyperresponsiveness is usually associated with a diagnosis of asthma or symptoms of wheezing, some individuals with rhinitis show airway hyperresponsiveness as do some with no symptoms whatsoever. We have studied the correlations between symptoms, airway hyperresponsiveness and atopy as determined by skin-prick tests in a cohort of New Zealand children. A total of 662 members of a birth cohort were studied at age 13 years using a respiratory questionnaire, skin-prick tests to 11 common allergens, and an abbreviated validated methacholine challenge test to determine airway responsiveness. Airway hyperresponsiveness (methacholine PC20 FEV1 < or = 8 mg/ml) was strongly correlated with reported asthma and current wheezing (P<0.0001) and also with atopy, especially to house dust mite and cat (P<0.0001). As weal size for both house dust mite and cat increased, so did the proportion of children with airway hyperresponsiveness. All children with diagnosed asthma and airway hyperresponsiveness were atopic. Skin-test reactions to house dust mite and cat were strongly correlated with any degree of measurable airway responsiveness (PC20 FEV1 < or = 25 mg/ml) in children with rhinitis (P<0.00001), and remained significantly correlated even in children without current asthma, without asthma ever and without rhinitis (P<0.001). Atopy is a major determinant of airway hyperresponsiveness in children, not only in those with reported histories of asthma and wheezing, but also in the absence of any history suggesting asthma and rhinitis.

Adolescent↗
PubMed2005

A polymorphism in the promoter region of the human interleukin-16 gene is not associated with asthma or atopy in an Australian population.

BACKGROUND: IL-16 is an immunomodulatory cytokine whose expression is increased in the bronchial mucosa, bronchoalveolar lavage fluid and induced sputum of asthmatic patients. It has been suggested that IL-16 has a regulatory role in the pathophysiology of asthma. A single-nucleotide polymorphism (T(-295)C) has been described in the promoter region of the gene and it has been hypothesized that this polymorphism may be associated with altered levels of IL-16 expression, and account for the increased levels of IL-16 seen in the asthmatic airway. OBJECTIVE: To determine the association between the T(-295)C promoter polymorphism and asthma, disease severity and atopy in a large Australian Caucasian population. METHODS: We used PCR and restriction fragment length polymorphism analysis to establish the allele frequency of the T(-295)C promoter polymorphism in a random Australian Caucasian population (n=176) and to characterize the polymorphism in a large Australian Caucasian population of mild (n=273), moderate (n=230) and severe (n=77) asthmatic patients, and non-asthmatic controls (n=455). Genotype association analyses were performed using chi(2) tests. RESULTS: The polymorphic C allele was present in 19% of the asthmatic population and 21% of the non-asthmatic population. There was no association between the polymorphism and asthma (P=0.153) nor with asthma severity (P=0.417) or atopy (P=0.157) in this population. CONCLUSION: Although it has been hypothesized that the T(-295)C promoter polymorphism may be associated with increased IL-16 gene expression, it is not associated with asthma, disease severity or atopy in this Australian population.

Adult↗
PubMed2005

The association between birth size and atopy in young North-European adults.

BACKGROUND: There is evidence that atopic disorders may begin in intra-uterine life; however, studies of birth characteristics and atopy show conflicting results. METHODS: We wanted to investigate the association of birth weight and head circumference with serum total or specific IgE, allergic rhinitis or eczema while addressing the influence of demographic and geographical factors. In this historic prospective cohort study, data were collected from birth records for 1683 men and women born in 1947-1973, from six Nordic-Baltic populations participating in the European Community Respiratory Health Survey. Blood tests for the measurement of serum total and specific IgE were available for 1494 subjects. In multiple regression analyses, adjustments were made for birth length, gender, age, study centre, adult body mass index, level of education, parental and adult smoking. RESULTS There was no association of birth weight (n=1230) and head circumference (n=285) with serum total IgE, specific IgE antibodies, allergic rhinitis or eczema. There were neither significant interactions by gender or age, nor heterogeneity between the study centres in the analyses of birth weight and adult atopy. CONCLUSION: Birth size was not associated with atopy among adults in this large Nordic-Baltic population study.

Adult↗
PubMed2006

Allergen-induced interleukin-9 production in vitro: correlation with atopy in human adults and comparison with interleukin-5 and interleukin-13.

BACKGROUND: The contribution of IL-9 to human atopy is supported by genetic studies. However, IL-9 production in response to allergen in vitro has been reported only in children. OBJECTIVE: Study IL-9 induction by allergen in adults, compare it with IL-5 and IL-13 and evaluate its association with atopy. METHODS: Peripheral blood mononuclear cell (PBMC) from control adults and from atopic patients were cultured with various allergens or phytohaemagglutinin (PHA) and secreted IL-5, IL-9 and IL-13 were measured by ELISA. RESULTS: IL-9 was produced in response to Dermatophagoides pteronyssinus (Der p) by PBMC from Der p-hypersensitive adults at levels equivalent to those induced by PHA but with slower kinetics. The induction of IL-9 was allergen specific, reflecting donor RAST profile. In Der p-triggered reactions of non-atopic and atopic subjects, IL-9 showed the highest selectivity for atopics, IL-5 and IL-13 being produced more frequently in non-atopic donors. Significant correlations with specific IgE titres were found for IL-9 with all allergens tested (Der p and two peptides of Bet v 1 birch allergen). For IL-5 and IL-13, they were in the same range for Der p but more variable for birch allergens. Patterns of cytokine production by individual patients in response to allergen reflected these differences: for Der p, IL-5, IL-9 and IL-13 productions were strongly correlated but for birch IL-5 differed from the latter two. The in vitro production of IL-9 reflected clinical hypersensitivity profiles and was higher in individuals with asthma than in those with disease limited to rhinitis and/or conjunctivitis. CONCLUSIONS: Allergen-triggered IL-9 production in vitro is an excellent marker for atopy in adults given its virtual absence in allergen-stimulated PBMC from non-atopic individuals and its correlation with allergen-specific IgE and asthma.

Adult↗
PubMed2005

Atopy patch testing with aeroallergens in patients with atopic dermatitis and controls in Singapore.

The role of allergy in atopic dermatitis is controversial. The atopy patch test (APT) has been used to investigate the association between atopic dermatitis and aeroallergen allergy. To determine the proportion of patients with atopic dermatitis with positive patch tests to common local aeroallergens and to compare this to controls with and without respiratory atopy, we performed APT, skin-prick tests (SPT) and IgE radioallergosorbent tests (RAST) on 73 patients with atopic dermatitis and on 38 nonatopic controls (13 with and 25 without respiratory atopy). The allergens used were house dust mite, cat dander, Bermuda grass and German cockroach. Only the APT for house dust mite showed a significant difference between the two groups. APT for house dust mite correlated with the RAST test, while APT for cat fur correlated with the SPT. The APT may be useful to evaluate aeroallergens in atopic dermatitis, but further work is needed to make it more reliable.

Adolescent↗
PubMed2005

Association between atopy and recurrent vaginal candidiasis.

To determine whether there is an association between atopy and recurrent vaginal candidiasis (RVC) and to evaluate the type-2 immune response in patients with RVC. Evaluation of immediate hypersensitivity skin tests to aeroallergens, measurement of total IgE and Candida albicans specific IgE and levels of IL-5 in 44 women with RVC and 26 with sporadic vaginal candidiasis (SVC). Statistical analyses were performed by Mann-Whitney test and chi(2) test with Yates correction. History of atopy (68%) and positive skin test (42%) were higher (P < 0.05) in RVC than in patients with SVC. No significant difference was found in total IgE, C. albicans specific IgE and IL-5 levels. There was a strong association between atopy and RVC, but type-2 immune response to C. albicans antigen was absent or similar in the two groups of patients.

Adolescent↗
PubMed1977

Impaired responses of growth hormone and blood eosinophils to L-dopa in atopy.

In order to assess whether response to the natural precursor of catecholamines in the nervous system is impaired in atopy, 500 mg L-dopa was administered to 13 atopic patients with bronchial asthma or hay fever and 13 sex-and-age-matched control subjects. The blood eosinophil count and growth hormone (GH) levels were then determined periodically over a 4-h period. The eosinophil count rose significantly 30 and 60 min after L-dopa in healthy subjects, but not in the atopic patients. The mean rise in GH 30 and 60 min after L-dopa was significantly lower in atopic patients as compared with controls. Injection of apomorphine 0.75 mg elicited increase in GH in nine of the 10 control subjects, but only in six of the 11 atopic patients. These results indicate that central dopaminergic stimulation is often impaired in patients with atopy. In testing GH release, atopy should be considered among the causes of failure to respond.

Apomorphine↗
PubMed1981

Children's atopy and mastocytosis in the nasal smear.

Nasal secretion samples from 473 children aged 0--15 years were studied in order to evaluate the role of mast cells in the nasal smear in different types of atopy and food allergy. The occurrence of eosinophils in the nasal secretion and in the blood, and susceptibility to upper respiratory infection were recorded. A mast cell count of more than 20 cells per slide was indicative of atopy and there was a clear correlation between eosinophilia and mastocytosis in the nasal smear. No type of allergy seemed to be significantly predominant in the total material, but in young children aged 0--3 years mastocytosis was clearly related to food allergy. The examination of nasal smears for mast cells is a valuable test in diagnosing atopy in children and especially food allergy among young children. However, the test is not reliable enough to be used as a single screening test.

Adolescent↗