The association between atopy and asthma in a semirural area of Tanzania (East Africa)

BACKGROUND: Atopy is consistently associated with asthma, except in a study in Africa. We assessed the association between atopy and asthma in women from a semirural area of Tanzania (East Africa). METHODS: All pregnant women delivering at the district hospital during a 1-year period were recruited (n = 658, 60.6% of those selected). Asthma was investigated by a standard questionnaire and atopy by specific IgE (immunoglobulin E) antibodies to Dermatophagoides pteronyssinus (Der p 1) and cockroach. RESULTS: The prevalence of wheezing chest was 10.7%; of asthma, 3.5%. Levels of specific IgE of >0.35 kU/l (73%) and high levels of total IgE (62% higher than 1000 kU/l) were highly prevalent. Specific IgE antibody levels in sera were not associated with asthma (3.8% of women with negative specific IgE to any antigen had asthma in comparison to 4.0% of women with positive specific IgE; odds ratio [OR] = 1.06, 0.35-3.22). Total IgE was not different between women with asthma and women without asthma (P=0.36). CONCLUSIONS: In tropical regions, the association between allergy and asthma is complex, and specific IgE reactivity to environmental allergens may not be related to asthma.     

Clinical features of atopic dermatitis and a family history of atopy

In 365 children and 213 adults the characteristics of atopic dermatitis isolated by Hanifin and Rajka were analysed in relation to a family history of allergy. A positive history in both parents and/or their families was associated with higher IgE titres, earlier appearance of skin changes, more frequent occurrence of urticaria, allergic respiratory diseases, cheilitis, and, in women, nipple eczema. These changes were less frequent and the IgE titre was lower in patients with one atopic parent, and even less frequent (or lower IgE titre) in patients with no family history of atopic disease, although the latter difference was sometimes slight.     

The association between infant feeding practices and subsequent atopy among children with a family history of asthma

BACKGROUND: Although longer duration of breastfeeding and later introduction of solid foods are both recommended for the prevention of asthma and allergic disease, evidence to support these recommendations is controversial. OBJECTIVE: To examine the relation between infant feeding practices and the risk of asthma and allergic disease at age 5 years. METHODS: A cohort of children with a family history of asthma in Sydney, Australia, was followed from birth to age 5 years. Data on infant feeding practices and on early manifestations of eczema were collected prospectively. The presence of eczema, asthma and atopy (positive allergen skin prick tests) were determined at age 5 years. RESULTS: In 516 children evaluated at age 5 years, there was no significant association between the duration of breastfeeding or timing of introduction of solid foods and protection against asthma or other allergic disease, after adjustment for confounding factors. However, breastfeeding for 6 months or more and introduction of solid foods after 3 months were both associated with an increased risk of atopy at age 5 years (P=0.02 and 0.01, respectively). There was no significant association between the presence of eczema at 4 weeks and at 3 months and continued breastfeeding beyond those times. CONCLUSION: Longer duration of breastfeeding and later introduction of solid foods did not prevent the onset of asthma, eczema or atopy by age 5 years.     

The severity of atopic dermatitis and the relation to the level of total IgE,onset of atopic dermatitis and family history about atopy

The aim of this study is the evaluation, if the level of total IgE, onset of atopic dermatitis (AD) and the family history are in the significant dependence to the severity of AD. The statistical evaluation of the dependence between the severity of AD and the the level of total IgE, family history and onset of AD was performed. 296 patients were examined. The level of total IgE above 200 IU/ml is recorded in 93 % of patients suffering from severe form and the positive data about atopy in family history are recorded in 66 % of patients with severe form of AD. The significant dependence was recorded between the severity of AD and parameters such as the level of total IgE, and family history about atopy. No dependence was recorded between the severity of AD and the onset of AD.     

Polymorphism of the mast cell chymase gene (CMA1) promoter region: lack of association with asthma but association with serum total immunoglobulin E levels in adult atopic dermatitis

BACKGROUND: Mast cell chymase has the potential to be an important mediator of inflammation and remodelling in the asthmatic lung. Previous studies have examined association between promoter polymorphism of the chymase gene (CMA1) and allergic phenotypes but the significance of this polymorphism is unclear. We have examined association of a CMA1 variant in relation to asthma in a large UK Caucasian family cohort. METHODS: A polymorphism of the CMA1 gene promoter (-1903G/A) was genotyped in 341 asthmatic families and in 184 non-asthmatic adults recruited from the UK PCR-RFLP based genotyping. Association with asthma diagnosis, atopy, specific and total IgE, and atopy and asthma severity was examined. RESULTS: Case-control studies did not reveal a significant difference in allele frequency between asthmatics and controls. A significant association was found between CMA1 genotypes and total IgE levels in subjects with self-reported eczema that remained significant after correction for multiple testing (median total serum IgE GG 297 kU/L, GA 144 kU/L, AA 48.4 kU/L, Pc=0.0032). CONCLUSION: These data suggest that CMA1 promoter polymorphism does not contribute to asthma susceptibility or severity but may be involved in regulating IgE levels in patients with eczema.     

A lower prevalence of atopy symptoms in children with type 1 diabetes mellitus

BACKGROUND: The Th1/Th 2 concept is a model to understand the pathophysiology of certain diseases. Atopic diseases (asthma, eczema and hayfever) are characterized by a chronic inflammatory reaction that is dominated by Th 2 cells, and type 1 diabetes mellitus (DM) is Th1 cell dominated. Because it is known that Th1 and Th 2 cells reciprocally counteract each other, it can be speculated that the prevalence of Th 2-mediated disease is lower in patients with Th1-mediated disease. OBJECTIVE: To compare the prevalence of atopic diseases between children with DM and age-matched controls. METHODS: Parents of children with DM were requested by Dutch paediatricians to complete the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire on the prevalence of atopic diseases. A control group was derived from a Dutch cross-sectional survey (the ISAAC2 study). RESULTS: We received 555 completed questionnaires, which is estimated to be 25% of the total number of Dutch children with DM. The control group consisted of 777 children. After age-matching, the questionnaires of 188 DM patients were used. Symptoms of asthma, hayfever and eczema were reported less in the group of children with DM compared with the control group (wheeze last year, OR 0.796, 95% CI 0.408-1.554; hayfever symptoms last year, OR 0.642, 95% CI 0.369-1.118; eczema symptoms last year, OR 0.693, 95% CI 0.430-1.115). CONCLUSION: The lower prevalence of astma, hayfever and eczema symptoms in DM patients compared with age-matched controls, although not statistically significant, is consistent with the Th1/Th 2 concept.     

Pollen counts in relation to the prevalence of allergic rhinoconjunctivitis, asthma and atopic eczema in the International Study of Asthma and Allergies in Childhood (ISAAC)

BACKGROUND: Although pollens are major allergens associated with allergic rhinoconjunctivitis and asthma, there is little information about the relative prevalence of these conditions in populations with different pollen exposures. OBJECTIVE: The purpose of this study was to investigate the relationship between pollen exposure and allergic symptoms among children in different countries. METHODS: An ecological analysis was conducted to see whether pollen exposure (pollen counts, and duration and severity of pollen seasons) is associated with symptoms of allergic rhinoconjunctivitis, asthma and atopic eczema in 28 centres within 11 countries (nine being in Europe). Data on the prevalence of symptoms in 13-14-year olds were based on the responses to the written questionnaires from the International Study of Asthma and Allergies in Childhood (ISAAC). The analysis was adjusted for gross national product and mean annual relative humidity. RESULTS: There was little relationship between pollen exposure and symptom prevalence, except for a significant inverse association between grass pollen counts and lifetime prevalence of the symptoms of allergic rhinitis (P=0.03). Almost all the regression coefficients were negative. The associations were even weaker and all non-significant when the analyses were conducted within countries, using a random intercept fixed slope model, but there was still no evidence of a positive association between pollen exposure and symptoms. CONCLUSION: There is a weak but consistent tendency for the prevalence of allergic symptoms to be inversely associated with pollen exposure. This finding accords with evidence from several countries, suggesting that the prevalence of hayfever and asthma tends to be lower in rural than in urban areas, and lowest among people living on farms. Exposure to allergenic pollen in early life does not appear to increase the risk of acquiring symptoms of respiratory allergy, and may even give some protection against them.     

Sibling effect on atopy in children of patients with asthma.

BACKGROUND: Multiple population studies have shown the presence of a sibling effect on atopic disease. However, it is unclear if the sibling effect is also of importance in subjects who are genetically at high risk for the development of atopy. OBJECTIVE: To study the presence of a sibling effect on markers of atopy (serum total IgE, specific IgE, skin tests) and asthma (bronchial hyper-responsiveness to histamine) in families ascertained through a parent with asthma. METHODS: First-degree offspring in 200 asthma families were studied (n = 541). Mixed effects regression models were used to account for the dependence of the observations within a family, and to adjust for possible confounding variables. RESULTS: Multiple regression analysis showed that having older siblings was inversely related to atopy, defined as >/= 2, >/= 3, >/= 4, or >/= 5 skin tests (P = 0.07-0.009). In addition, family size (number of siblings) had a significant protective effect on the presence of specific IgE to common aeroallergens (P = 0.03). Exposure to cigarette smoke in the first 3 years of life significantly increased the risk of having specific IgE to common aeroallergens (P = 0.04). No sibling effect was detected for serum total IgE or bronchial hyper-responsiveness to histamine. CONCLUSIONS: This study shows a protective sibling effect on the presence and severity of atopy but not on bronchial hyper-responsiveness in children who are genetically at risk. The identification of the sibling effect in high-risk families stresses the need to understand the basis of this effect, in order to design future prevention programmes.     

No association between vitamin D and atopy,asthma, lung function or atopic dermatitis: a prospective study in adults

Studies suggest that vitamin D may be involved in the pathogenesis of allergic disorders, asthma and decreased lung function. However, results are inconsistent and only few prospective studies have examined adults. The purpose of this study was to investigate the association of serum 25‐hydroxy vitamin D (s25(OH)D) with atopy, atopic dermatitis (AD), asthma, wheezing and impaired lung function in a prospective study of Danish adults. A random sample of 3471 persons was examined in 2006–2008. Of these, 2308 were re‐examined 5 years later. s25(OH)D and specific IgE against four common inhalant allergens were measured by standard procedures. Wheezing, asthma and AD were assessed from questionnaires and lung function was measured by spirometry. We found no statistically significant associations between s25(OH)D and prevalence or incidence of atopy, AD, asthma or wheezing. Associations with lung function were inconsistent. We conclude that vitamin D status does not influence these conditions in adults.     

哮喘家系的特应质性状遗传学分析

目的 对哮喘家系的特应质性状进行遗传分析.方法 收集哮喘家系,对所有人进行血清IgE的测定、皮肤挑刺试验和支气管激发试验.结果 ①家系内哮喘病人和正常人SPT阳性有显著差异(P<0.05).②血清总IgE增高个体SPT阳性百分数为76%,在正常个体SPT阳性百分数为53%,在两组之间有显著的差异(P<0.05).③父母双方均为SPT阳性其子女SPT的阳性率为85.7%,父亲为SPT阳性而母亲正常其子女SPT的阳性率为81.8%,父亲正常母亲为SFT阳性其子女SPT的阳性率为63.6%,父母中任一方SPT阳性与父母SPT均正常其子女SPT阳性率比较有显著差异(P<0.05).结论 哮喘家系中病人特应质更明显;血清总IgE升高与SPT阳性有相关性.父母双方特应质对其子女特应质的影响最大.     

Pertussis IgE and atopic disease

Background Pertussis toxin (PT) stimulates IgE production in animals, and pertussis vaccination and whooping cough may have similar effects in man. Methods We analyzed IgE responses to PT (FT-IgE) in sera from children primarily immunized with three doses of either an acellular 2- or 5-component vaccine, or a whole-cell (We) pertussis vaccine, and in children after whooping cough. The study comprised 50 children with both atopic disease and positive skin prick test, 99 nonatopic controls, and 40 children with verified pertussis.
Results Immunoglobulin E antibodies against PT were demonstrated in 19% and 24% of sera from vaccinated children at 7 and 12 months, respectively, and in 9% at 2.5 years. At 7 months, PT-IgE was more common after vaccination with acellular (24%) than with the We vaccine (3%, P = 0,02), PT-IgE was also more common (P = 0.00l) after vaccination in children classified as atopic (36%) than in the control group (10%). Thirty percent of the children with pertussis had PT-IgE, more often so in atopic than nonatopic children (P = 0.02), Conciusions Transient production of PT-lgE seems to be common after primary pertussis immunization with acellular vaccines, and after whooping cough, particularly in atopic subjects.     

The low prevalence of allergic disease in Eastern Europe

Background The prevalence of allergic disease is known to be low in Eastern Europe.
Objective To assess the association of suspected risk factors, including several closely linked to the hygiene hypothesis, with allergic symptoms and atopic sensitization in young school-aged children.
Methods Observational study of 13 889 Belarusian children followed up at age 6.5 years in the Promotion of Breastfeeding Intervention Trial (PROBIT). Allergic symptoms and diseases were based on parental responses to the International Study of Asthma and Allergy in Childhood questionnaire, and prick tests to five common inhalant allergens were performed using standard methods.
Results Significantly increased risks of wheezing and hayfever symptoms in the past 12 months, and of recurrent itchy rash were observed in boys, children with a positive first-degree family atopic history, and those who had received probiotics (especially as prophylaxis with antibiotic use). Pet ownership, contact with farm animals, the presence and number of younger and (especially) older siblings, and residency in rural areas of Western Belarus were associated with reduced risks. Maternal postnatal smoking was associated with wheezing and hayfever symptoms, while the duration of exclusive breastfeeding was not protective against any of the studied outcomes. The risk factors for allergic symptoms were similar in children with positive skin-prick tests to those in the overall cohort.
Conclusion Many of the risk and protective factors we identified are consistent with those reported in Western countries and with the hygiene hypothesis. Further research on dietary and other environmental and genetic factors is necessary to understand the low prevalence of allergic disease in Belarus and other Eastern European countries.     

The burden of atopy and asthma in children

Background:  There has been a world-wide increase in the prevalence of atopic diseases. These atopic diseases, including asthma, allergic rhinoconjunctivitis and atopic eczema/dermatitis, are common in childhood and create a challenge of management for physicians and parents.
Methods:  MEDLINE was searched for articles related to atopy, allergy asthma, allergic rhinoconjunctivitis and atopic eczema/dermatitis.
Results and conclusions:  The conditions of asthma, allergic rhinoconjunctivitis and atopic eczema/dermatitis cause very significant burdens regarding the discomfort to the affected individual, management problems for the parent and physician and the economic cost to the family and the nation.     

Association between first-degree familial predisposition of asthma and atopy (total IgE) in newborns

BACKGROUND: It is generally thought that infants with a first-degree familial predisposition of asthma are at higher risk of developing asthma than infants without predisposition. OBJECTIVE: To investigate whether there is an association between being at high risk for developing asthma and increased level of total IgE in newborns and whether total IgE is influenced by gender, family size, birth season, maternal smoking, birth weight, gestational age, and maternal diet. METHODS: Two hundred and twenty-one high risk and 308 low-risk infants were prenatally selected in a 5-year-period. Three to 5 days after birth, the total IgE was measured in capillary heel blood. RESULTS: Data on total IgE and first-degree familial predisposition were available for 170 high-risk and 300 low-risk infants. There was a statistically significant relationship between being at high-risk (maternal asthma) and increased levels of total IgE in newborns (total IgE cut-off levels: 0.6-0.9 IU/mL (odds ratio (OR)=2.1, 95% confidence interval (CI): 1.2-3.7 to 3.0, 95% CI: 1.5-5.9)), between being born in autumn and increased levels of total IgE in newborns [total IgE cut-off levels: 0.5-0.6 IU/mL (OR=2.5, 95% CI: 1.2-5.1 to 2.5, 95% CI: 1.2-5.4)] and between maternal vitamin supplements intake and decreased levels of total IgE in newborns (total IgE cut-off level: 0.9 IU/mL (OR=0.5, 95% CI:0.3-1.0)). There was no interaction between the effects of maternal asthma and birth season on total IgE, as well as between the effects of maternal asthma and maternal vitamin supplements intake. Gender, family size, maternal smoking, birth weight, and gestational age did not influence the associations. CONCLUSION; Being at high-risk of asthma (maternal asthma) and birth season are positively associated with the presence of increased levels of total IgE at birth, whereas maternal vitamin supplements intake is negatively associated with the presence of total IgE at birth.     

Hydrocortisone enhances allergen-specific IgE production by peripheral blood mononuclear cells from atopic patients with high serum allergen-specific IgE levels.

BACKGROUND: Although there is convincing evidence that human B cells can be induced to produce IgE by a combination of interleukin 4 (IL-4) and hydrocortisone (HC) in atopic subjects, it is still uncertain if this performs the same functions in allergen-specific IgE synthesis. OBJECTIVE: This study was designed to investigate the differences of IgE regulation between atopics and nonatopics, interactions of HC with IL-4, and the correlation between in vitro total IgE, allergen-specific IgE synthesis and serum IgE levels. METHODS: Peripheral blood mononuclear cells (PBMCs) from 16 atopic asthma patients sensitive to Dermatophagoides farinae and seven nonatopic controls were cultured with IL-4 and/or HC. Total IgE and D. farinae-specific IgE in culture supernatant were measured by ELISA and FAST. RESULTS: IL-4 increased total IgE synthesis in PBMCs from both atopics and nonatopics, whereas, HC had this effect only in some atopics who showed spontaneous IgE production in vitro. HC acted synergistically with IL-4 in total IgE synthesis. Their effects were more remarkable in cases with lower total serum IgE levels. PBMCs from eight of 16 atopics produced D. farinae-specific IgE in vitro either spontaneously or by IL-4 and/or HC. HC had more profound effects than IL-4 in these patients. They also showed higher total IgE synthesis by HC, and higher specific serum IgE levels than the others. IL-4 and/or HC did not induce any D. farinae-specific IgE synthesis by PBMCs from nonatopics. CONCLUSION: HC had a more profound effect than IL-4 on the induction of D. farinae-specific IgE synthesis in atopic patients with high serum allergen specific IgE levels. Further studies to determine the causes of these effects, such as the presence of long lived allergen specific B cells as the result of the priming effect of IL-4 in vivo, may be needed.     

The association of early life exposure to antibiotics and the development of asthma,eczema and atopy in a birth cohort: confounding or causality?

Background In general, studies reporting positive associations between antibiotic exposure and respiratory and allergic disease have been unable to determine the nature of this association.
Objective To examine the association between antibiotic exposure in infancy and the development of asthma, eczema and atopy in early childhood.
Methods In a birth cohort study, we collected reported antibiotic exposure before 3 months and before 15 months along with outcomes (wheeze, asthma, eczema, rash, inhaler use) at 15 months ( n =1011) and 4 years ( n =986). Atopy was measured using skin prick tests at 15 months.
Results We found significant univariate associations of antibiotic exposure before 3 months with asthma developing between birth and 15 months [OR 2.32 (95% CI 1.45–3.69)]. After adjustment for chest infections, this association reduced (OR=1.58, 95% CI 0.96–2.60) becoming marginally significant ( P =0.07). A marginally significant association of antibiotics with atopy (OR=1.44, 95% CI 0.96–2.14) in the univariate analysis also reduced after adjustment for chest infections (OR=1.36, 95% CI 0.91–2.05). There was no effect of antibiotic exposure before 15 months on asthma developing after 15 months and present between 3 and 4 years (OR=1.35 95% CI 0.85–2.14). Antibiotic exposure before 3 months was not associated with eczema and rash developing between birth and 15 months but exposure before 15 months was related to eczema [OR 1.83 (95% CI 1.10–3.05)] and rash [OR 1.61 (95% CI 1.02–2.53)] developing after 15 months and remaining present at 4 years. These effects reduced in the multivariate analysis.
Conclusions Our findings suggest that the effect of antibiotics on respiratory disease may be due to confounding by chest infections at an early age when asthma may be indistinguishable from infection.