Role of microbial burden in aetiology of allergy and asthma

Early age of dog exposure is negatively associated with atopic dermatitis: A comprehensive analysis

BACKGROUND

Currently, whether exposure to pets is a protective factor for atopic dermatitis (AD) is controversial.

OBJECTIVE

To investigate the association of pet exposure in early life with the incident AD.

METHODS

This study was based on PRISMA. The authors independently searched PubMed, Cochrane Library, and EMBASE. We gathered cohort studies reporting on the ratio of pet exposure and incident AD and meta-analyzed them by relative risks (RRs) and 95% confidence interval (CI). Newcastle-Ottawa Scale (NOS) and funnel plot were performed to evaluate the quality of the study and publication bias, respectively. P < 0.05 was considered statistically significant.

RESULTS

We included 23 studies comprising 3174-25,527 participants with exposure age 0-12. The quality of included studies was generally gorgeous, with NOS 5-8. Dog exposure was negatively associated with the incident AD, with RRs of 0.82 (P = 0.002), but this trend was insignificant in cats (RR = 1.08; P = 0.490) and other pets (RR = 0.94; P = 0.550). Subgroup analysis showed participants exposed to dogs had a further lower AD risk in the North American populations (RR = 0.60; P < 0.001). Publication bias was not supported by the funnel plot.

CONCLUSION

This study finds exposure to dog pets in early life is negatively associated with newly developed AD, especially in North American populations.

IMPACT

Currently, whether exposure to pets is a protective factor for atopic dermatitis (AD) is controversial. This study finds exposure to dog pets in early life is negatively associated with newly developed atopic dermatitis, and this trend is more remarkable in North American populations. Associations of exposure to cats and other pets with atopic dermatitis are not found. These results discover a novel insights to prevention AD and related diseases.

Association of Asthma Risk Alleles With Acute Respiratory Tract Infections and Wheezing Illnesses in Young Children

BACKGROUND

Genome-wide association studies have identified several risk alleles for early childhood asthma, particularly in the 17q21 locus and in the cadherin-related family member 3 (CDHR3) gene. Contribution of these alleles to the risk of acute respiratory tract infections (ARI) in early childhood is unclear.

METHODS

We analyzed data from the STEPS birth-cohort study of unselected children and the VINKU and VINKU2 studies on children with severe wheezing illness. Genome-wide genotyping was performed on 1011 children. We analyzed the association between 11 preselected asthma risk alleles and the risk of ARIs and wheezing illnesses of various viral etiologies.

RESULTS

The asthma risk alleles in CDHR3, GSDMA, and GSDMB were associated with an increased rate of ARIs (for CDHR3, incidence rate ratio [IRR], 1.06; 95% confidence interval [CI], 1.01-1.12; P = .02), and risk allele in CDHR3 gene with rhinovirus infections (IRR, 1.10; 95% CI, 1.01-1.20, P = .03). Asthma risk alleles in GSDMA, GSDMB, IKZF3, ZPBP2, and ORMDL3 genes were associated with wheezing illnesses in early childhood, especially rhinovirus-positive wheezing illnesses.

CONCLUSIONS

Asthma risk alleles were associated with an increased rate of ARIs and an increased risk of viral wheezing illnesses. Nonwheezing and wheezing ARIs and asthma may have shared genetic risk factors. Clinical Trials Registration. NCT00494624 and NCT00731575.

The hygiene hypothesis for allergy - conception and evolution

In 1989, a short paper entitled "Hay fever, hygiene and household size" observed that British children from larger families were less likely to develop hay fever and suggested that this could be because early exposure to infection prevents allergy. This sibship size association for hay fever, since replicated many times in Britain and other affluent countries and confirmed by objective measures of atopy, prompted what has come to be known as the "hygiene hypothesis for allergy", although that term was not specifically used in the 1989 paper. The present paper reviews the historical roots of the "hygiene hypothesis" and charts its development over more than 30 years. Initial scepticism among immunologists turned to enthusiasm in the mid-1990s as the Th1/Th2 paradigm for allergic sensitisation emerged from animal experiments and the concept of "immunological old friends" became popular from the early 2000s. From the late 1990s, observations of reduced allergy risk among children of anthroposophic families and those brought up on farms suggested that the sibship size effects formed part of a broader range of "hygiene-related" determinants of allergy. Children from large families with farming exposure have approximately sixfold reduction in prevalence of hay fever, indicating the potential strength and epidemiological importance of these environmental determinants. During the 21st century, a wide range of specific microbial, environmental and lifestyle factors have been investigated as possible underlying mechanisms, but sadly none have emerged as robust explanations for the family size and farming effects. Thus, while the "hygiene hypothesis" led to a fundamental reappraisal of our relationship with our microbial environment and to the concept that early exposure, rather than avoidance, is beneficial for developing a healthy immune system, the underlying mechanism for variations in allergy prevalence with family size remains, in Churchillian terms, "a riddle wrapped in a mystery inside an enigma".

Biomarker-driven feedback control of synthetic biology systems for next-generation personalized medicine

Many current clinical therapies for chronic diseases involve administration of drugs using dosage and bioavailability parameters estimated for a generalized population. This standard approach carries the risk of under dosing, which may result in ineffective treatment, or overdosing, which may cause undesirable side effects. Consequently, maintaining a drug concentration in the therapeutic window often requires frequent monitoring, adversely affecting the patient’s quality of life. In contrast, endogenous biosystems have evolved finely tuned feedback control loops that govern the physiological functions of the body based on multiple input parameters. To provide personalized treatment for chronic diseases, therefore, we require synthetic systems that can similarly generate a calibrated therapeutic response. Such engineered autonomous closed-loop devices should incorporate a sensor that actively tracks and evaluates the disease severity based on one or more biomarkers, as well as components that utilize these molecular inputs to bio compute and deliver the appropriate level of therapeutic output. Here, we review recent advances in applications of the closed-loop design principle in biomedical implants for treating severe and chronic diseases, highlighting translational studies of cellular therapies. We describe the engineering principles and components of closed-loop therapeutic devices, and discuss their potential to become a key pillar of personalized medicine.

The effect of farming environment on asthma; time dependent or universal?

The increasing prevalence of asthma is linked to westernization and urbanization. Farm environments have been associated with a lower risk of asthma development. However, this may not be universal, as the association differs across birth cohorts and farming methods. The aim of this study was to investigate the associations of farm upbringing with asthma in different generations and at different times in history. The study population consisted of three generations: 13,868 subjects participating in the ECRHS in 2010, their 9,638 parents, and their 8,885 offspring participating in RHINESSA in 2013. Information on place of upbringing and self-reported ever asthma was provided via questionnaires. Logistic regression was performed including subgroup analysis stratified by generation and birthyear into ten-year-intervals. The prevalence of asthma increased from 8% among grandparents to 13% among parents and to 18% among offspring. An overall analysis showed an inverse association of farm upbringing on the risk of asthma (OR = 0.64; 95%CI 0.55-0.74). Subgroup analysis stratified into ten-year-intervals showed a tendency towards a more pronounced inverse association between growing up on a farm and asthma among subjects born in the 1940s (0.74; 0.48-1.12), 1950s (0.70; 0.54-0.90) and 1960s (0.70; 0.52-0.93). For subjects born in 1970 and thereafter this association appeared less consistent. While growing up on a farm was associated with a reduced risk of developing asthma in participants born between 1945-1999, this was mainly driven by generations born from 1945 to 1973.

Infection-exposure in infancy is associated with reduced allergy-related disease in later childhood in a Ugandan cohort

Background

Lack of early infection-exposure has been associated with increased allergy-related disease (ARD) susceptibility. In tropical Africa, little is known about which infections contribute to development of ARDs, and at which time.

Methods

We used latent class analysis to characterise the early infection-exposure of participants in a Ugandan birth cohort and assessed ARDs in later childhood.

Results

Of 2345 live births, 2115 children (90%) had data on infections within the first year of life while 1179 (50%) had outcome data at 9 years. We identified two latent classes of children based on first-year infection-exposure. Class 1 (32% membership), characterised by higher probabilities for malaria (80%), diarrhoea (76%), and lower respiratory tract infections (LRTI) (22%), was associated with lower prevalence of wheeze, eczema, rhinitis, and Dermatophagoides skin prick test (SPT) positivity at 9 years. Based on 5-year cumulative infection experience, class 1 (31% membership), characterised by higher probabilities for helminths (92%), malaria (79%), and LRTI (45%), was associated with lower probabilities of SPT positivity at 9 years.

Conclusions

In this Ugandan birth cohort, early childhood infection-exposure, notably to malaria, helminths, LRTI, and diarrhoea, is associated with lower prevalence of atopy and ARDs in later childhood.

Funding

This work was supported by several funding sources. The Entebbe Mother and Baby Study (EMaBS) was supported by the Wellcome Trust, UK, senior fellowships for AME (grant numbers 064693, 079110, 95778) with additional support from the UK Medical Research Council. LL is supported by a PhD fellowship through the DELTAS Africa Initiative SSACAB (grant number 107754). ELW received funding from MRC Grant Reference MR/K012126/1. SAL was supported by the PANDORA-ID-NET Consortium (EDCTP Reg/Grant RIA2016E-1609). HM was supported by the Wellcome's Institutional Strategic Support Fund (grant number 204928/Z/16/Z).

Associations between the Gut Microbiota, Immune Reconstitution, and Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation

Immune reconstitution following allogeneic hematopoietic stem cell transplantation (allo-HSCT) sets the stage for the goal of a successful transplant—the prevention of disease relapse without graft versus host disease (GVHD) and opportunistic infection. In both epidemiologic studies and in controlled animal studies, it is known that the gut microbiome (GM) can profoundly influence normal innate and adaptive immune development and can be altered by microbial transfer and antibiotics. Following allo-HSCT the GM has been shown to influence clinical outcomes but published associations between the GM and immune reconstitution post-allo-HSCT are lacking. In this viewpoint we propose that the extensive knowledge garnered from studying normal immune development can serve as a framework for studying immune development post-allo-HSCT. We summarize existing studies addressing the effect of the GM on immune ontogeny and draw associations with immune reconstitution and the GM post-allo-HSCT.

Trajectories of early-onset rhinitis in the Singapore GUSTO mother-offspring cohort

BACKGROUND

The natural history of childhood rhinitis is not well described.

OBJECTIVE

This study aimed to identify different rhinitis trajectories in early childhood and their predictors and allergic associations.

METHODS

Rhinitis symptoms were ascertained prospectively from birth until 6 years using standardized questionnaires in 772 participants. Rhinitis was defined as one or more episodes of sneezing, runny and/or blocked nose >2 weeks duration. Latent trajectories were identified using group-based modelling, and their predictive risk factors and allergic associations were examined.

RESULTS

Three rhinitis trajectory groups were identified: 7.6% (n = 59) were termed early transient rhinitis, 8.6% (n = 66) late transient rhinitis, and 6.6% (n = 51) persistent rhinitis. The remaining 77.2% (n = 596) were classified as non-rhinitis/reference group. Early transient rhinitis subjects were more likely of Indian ethnicity, had siblings, reported childcare attendance, early wheezing and eczema in the first 3 years of life. Late transient rhinitis was associated with antenatal exposure to smoking, higher maternal education levels, and wheezing at age 36-72 months. Persistent rhinitis was associated with male gender, paternal and maternal history of atopy, eczema, and house dust mite sensitization.

CONCLUSIONS & CLINICAL RELEVANCE

Risk factors for early transient rhinitis involve a combination of genetic and early environmental exposures, whereas late transient rhinitis may relate to maternal factors and early respiratory infections independent of atopy. In contrast, persistent rhinitis is strongly associated with atopic risk and likely represents the typical trajectory associated with allergic disorders. Allergic rhinitis symptoms may commence as early as the first year of life and may inform development of early interventive strategies.

Variability of C-reactive protein in first-generation Ecuadorian immigrants living in the United States

OBJECTIVES

Establish the variability of C-reactive protein (CRP) within a population of first-generation immigrants living in the United States. Prior work has theorized that individuals with high levels of childhood pathogen exposure may have lower CRP levels in adulthood, and therefore that for these individuals, CRP may not be as accurate an index of chronic disease risk related to low-level inflammation as is presumed based on data from wealthy populations. This potentially has major implications for the interpretation of CRP as a biomarker of chronic inflammation.

METHODS

This longitudinal study collected a total of 125 dried blood spot (DBS) samples from 31 participants (median 4 samples each) and CRP levels in these DBS were assayed by enzyme-linked immunosorbant assay. Surveys were administered to characterize childhood pathogen exposure, and current illness. Variance was estimated using mixed effects regression models.

RESULTS

On average, participants were adults (mean = 41.9 years old) who had immigrated to the United States nearly 20 years prior to the study and had nearly universally experienced childhood helminth infection and other major pathogen exposures. Median serum-equivalent CRP was 0.77 mg/L. Individuals reliably differed in subacute CRP levels, and, depending on whether untransformed or log-transformed CRP was the outcome variable, 45% or 62% of variance in CRP was attributable to between-individual differences.

CONCLUSIONS

The variability of CRP levels in individuals with relatively high childhood pathogen exposure is comparable to previously reported studies in North America and Europe. However, CRP values are relatively low. CRP is an appropriate measure of subacute inflammation in this sample.

Antibiotics administration during last trimester of pregnancy is associated with atopic dermatitis - a cross-sectional study

INTRODUCTION

Studies regarding antibiotics administration during pregnancy and atopic dermatitis (AD) in children are only few. In this context, the objective of our study was to investigate the potential association between the timing of intrauterine exposure to antibiotics or prenatal antibiotic administration in general and AD occurrence in children.

METHODS

This was a cross-sectional study in 1046 subjects. The exposure to antibiotics during pregnancy was initially evaluated using simple logistic regressions. Then, each period of antibiotics administration was adjusted with the other periods of antibiotics exposure (model 1) and with the other variables associated with AD in our database (model 2).

RESULTS

In simple logistic regression analysis, the administration of antibiotics during pregnancy, as a whole period, presented a trend of association with AD (OR = 1.28, %CI: 0.99 - 1.65). When we analyzed antibiotic administration during each trimester of pregnancy, only antibiotherapy during the 3rd trimester was associated with AD (OR = 2.94, %CI: 1.21 - 7.12). After adjusting with all the other important risk factors associated with AD in the database, antibiotics administration during the 3rd trimester of pregnancy was still independently associated with AD (OR=2.64, %CI: 1.01 - 6.91).

CONCLUSION

Antibiotic administration during the 3rd trimester of pregnancy was independently associated with AD in children.

Whole-Cell Pertussis Vaccination and Decreased Risk of IgE-Mediated Food Allergy: A Nested Case-Control Study

BACKGROUND

Rates of food allergy have increased markedly in Australia and other high- income countries in recent years. On the basis of ecological observations, and the known immunologic characteristics of whole-cell pertussis (wP) compared with acellular pertussis (aP) vaccines, we hypothesized that wP vaccination in infancy protects against the development of food allergy.

OBJECTIVE

To determine whether infants who receive wP in infancy were less likely to develop IgE-mediated food allergy than those who received aP.

METHODS

Retrospective cohort-nested case-control study of Australian children born in the period 1997 to 1999, the period of transition from using wP-containing to aP-containing vaccines. Children diagnosed with IgE-mediated food allergy were individually matched to 10 controls by date of birth, socioeconomic decile, and jurisdiction of birth. The odds ratio of vaccination with wP versus aP among cases and matched controls was calculated using conditional logistic regression.

RESULTS

The odds ratio of receiving the first dose as wP (rather than aP) among cases of food allergy compared with controls was 0.77 (95% CI, 0.62-0.95). The results of secondary analyses (any dose as wP vs aP-only, and wP-only vs aP-only) were broadly similar.

CONCLUSIONS

Australian infants who received wP vaccines were less likely to be diagnosed with food allergy in childhood than contemporaneous children who received aP vaccines. If a protective effect is confirmed in a randomized controlled trial, wP or mixed wP and aP vaccination schedules could form part of an effective strategy for combating the rise in food allergies.

Complementary and Integrative Therapies for Childhood Atopic Dermatitis

Background: Childhood atopic dermatitis is a chronic inflammatory skin condition that causes significant psychological and financial costs to the individual and society. Treatment regimens may require long-term medication adherence and can be associated with poor patient satisfaction. There is considerable interest in complementary and integrative medicine (CIM) approaches for childhood atopic dermatitis. Objective: To assess the effects of CIM approaches on childhood atopic dermatitis outcomes as defined by randomized, controlled clinical trials. Methods: A PubMed review of CIM-related treatments for pediatric atopic dermatitis was performed, and data related to age, study population, efficacy, treatment regimen, length of treatment, and sample size were included. Results: The search yielded 20 trials related to probiotic/prebiotic treatments for atopic dermatitis, three on the effects of vitamins on children with atopic dermatitis, and two on the effects of Chinese herbal treatments for atopic dermatitis in children and adolescents. The strongest evidence was for supplementation with the probiotics L. fermentum and L. plantarum. Conclusions: Certain strains of probiotics, specifically L. plantarum and L. fermentum, may improve clinical severity scores in children with atopic dermatitis. However, additional trials are needed to more thoroughly delineate the effects of additional integrative therapies on childhood atopic dermatitis.

Microbial balance in the intestinal microbiota and its association with diabetes, obesity and allergic disease

Recent studies have been considered to symbiotic interactions of the human gastrointestinal microbiota and human lifestyle-related disorders. The human gastrointestinal microbiota continuously stimulates the immune system against opportunistic and pathogen bacteria from infancy. Changes in gastrointestinal microbiota have been associated with numbers of human diseases such as allergic diseases, autoimmune encephalitis, atherosclerosis, colorectal cancer, obesity, diabetes etc. In this review article, we evaluate studies on the roles of human gastrointestinal microbiota and interference pathogenicity in allergic diseases, obesity, and diabetes. Several studies indicated association between allergic diseases and changes in bacterial balance such as increased of Clostridium spp., some species of Bifidobacterium spp., or decreased of Bacteroidetes phylum and some species of Bifiobacterium spp. and production of specific short-chain fatty acids due to food type, delivery modes of infant, infant evolvement environment and time of getting bacteria at an early-life age. In addition, obesity and diabetes are associated with food type, production of short chain fatty acids undergo fermentation of the intestinal microbiota, metabolic endotoxemia, endocannabinoid system and properties of the immune system. Well-characterized underlying mechanisms may provide novel strategies for using prebiotic and probiotic to prevent and treatment of allergic diseases, obesity, diabetes, and other lifestyle-related disorders.

Effects of Migration on Allergic Diseases

Studies in migrant populations provide vital opportunities to investigate the role of environmental factors in the pathogenesis of allergic disorders. Differences in allergy prevalence have been observed between migrants and native-born subjects living in the same geographical location. Immigrants who migrate from less affluent countries with lower allergy prevalence tend to have a lower prevalence of allergic disorders compared to native-born residents of the more affluent host country. The patterns of allergic disease prevalence also differ between first- and second-generation migrants. The timing of migration in relation to birth, age at migration, and duration of residence in the host country also influence one's atopic risk. A complex interplay of multiple environmental, socioeconomic, and cultural factors is likely responsible for these observed differences. Further research into the roles of various risk factors in modulating differences in allergic disease prevalence between migrant and native populations will enhance our understanding of the complex gene-environment interactions involved in the pathogenesis of allergic disorders.

The role of the microbiome in childhood asthma

It is now well established that the healthy bronchial tree contains a microbiome distinct from that of the upper respiratory tract and that the lung microbiome may be dysregulated in individuals with a chronic respiratory disease, such as asthma. In addition, after birth, gut microbes interact with the host tissue, especially with the lymphatic tissue, thereby guaranteeing efficient immune activation. This review focuses on the available literature on the relationships between the gut microbiome, immune function and asthma in childhood, as well as the therapeutic strategies aimed at acting on the modulation of the microbiome.

Critical role of Toll-like receptors in pathophysiology of allergic asthma

Allergic asthma is an airway disease, characterized by reversible bronchoconstriction, chronic inflammation of the airway, and thickness of smooth muscle in the respiratory tract. Asthma is orchestrated by an excessive Th2-adaptive immune response, in which innate immunity plays a key role. Recently TLRs have received more and more attention as they are central to orchestrate the innate immune responses. TLRs are localized as integral membrane or intracellular glycoproteins with those on the cell surface sensing microbial antigens and the ones, localized in intracellular vesicles, sensing microbial nucleic acid species. Having recognized microbial antigens, TLRs conduct the immune response towards a pro- or anti-allergy response. As a double-edged sword, they could initiate either harmful or helpful responses by the immune system in case of allergic asthma. In the current review, we will describe the role of TLRs and their signaling pathways in allergic asthma.

mRNA-Mediated Gene Supplementation of Toll-Like Receptors as Treatment Strategy for Asthma In Vivo

Asthma is the most common chronic disease in childhood. Although several therapeutic options are currently available to control the symptoms, many drugs have significant side effects and asthma remains an incurable disease. Microbial exposure in early life reduces the risk of asthma and several studies have suggested protective effects of Toll-like receptor (TLR) activation. We showed previously that modified mRNA provides a safe and efficient therapeutic tool for in vivo gene supplementation. Since current asthma drugs do not take patient specific immune and TLR backgrounds into consideration, treatment with tailored mRNA could be an attractive approach to account for the patient's individual asthma phenotype. Therefore, we investigated the effect of a preventative treatment with combinations of Tlr1, Tlr2 and Tlr6 mRNA in a House Dust Mite-induced mouse model of asthma. We used chemically modified mRNA which is-in contrast to conventional viral vectors-non-integrating and highly efficient in gene transfer. In our study, we found that treatment with either Tlr1/2 mRNA or Tlr2/6 mRNA, but not Tlr2 mRNA alone, resulted in better lung function as well as reduced airway inflammation in vivo. The present results point to a potentially protective effect of TLR heterodimers in asthma pathogenesis.

Prevalence and risk factors for atopic disease in a population of preschool children in Rome: Challenges to early intervention

BACKGROUND

Allergic diseases are complex identities determined by an interplay of genetic and environmental factors, resulting in the clinical manifestation of the disease. So far in Italy, updated data about the prevalence and risk factors of respiratory and allergic diseases in preschool children are not available.

METHODS

Children aged 3-5 years, attending four different nursery schools in an urban district of the city of Rome. A standardized questionnaire developed under the SIDRIA-2 protocol was administered to the parents of the children for the assessment of the potential risk factors and the outcomes.

RESULTS

A total of 494 children were enrolled in the study; 289 of them (60.3%) performed a skin prick test (SPT). In the 12 months preceding the interviews, 15% of children experienced at least one episode of wheezing, 5.5% of allergic rhinitis, 11% of children had a doctor diagnosis of asthma, 12% of children who underwent the SPT were positive to at least one of the tested allergens, being diagnosed as atopic. The univariate analysis for the health outcomes of the study shows that asthma was positively associated with daycare attendance, mother's history of atopy, siblings' history of atopy, recurrent siblings' bronchitis, and dermatitis. Atopy was positively associated with mother's history of atopy and dermatitis, whereas there is a borderline protective association with recurrent siblings' bronchitis.

CONCLUSIONS

This study represents a first comprehensive epidemiological evaluation of prevalence of respiratory and allergic diseases in children aged 3-5 years in the city of Rome and an updating of the evolution of allergic diseases.

Exposure to 'farming' and objective markers of atopy: a systematic review and meta-analysis

There is growing interest in the 'farm effect' on the spectrum of allergy. Evidence concerning the farm effect on asthma, eczema, and allergic rhinitis has been systematically synthesized, but without a specific focus on objective markers of sensitization. This focus is important, as farm exposures may be related to allergy but not to non-allergic phenotypes of disease. We aimed to systematically review and meta-analyse literature that has investigated associations between farm exposure at any age and objective measures of atopy, that is serum IgE or skin prick tests results. Using predefined inclusion and exclusion criteria, we identified 29 articles for review. IgE levels were measured in either childhood or adulthood by eighteen studies, while skin prick testing was performed in sixteen studies. Newcastle-Ottawa Scale quality assessments indicated that the majority of these studies demonstrated a representative sample of selected participants. Due to significant heterogeneity in study measures and methodology between studies, only few were meta-analysed. This meta-analysis showed a significant protective effect of farm exposure before 1 year of life on allergic sensitization (OR = 0.60 [0.52-0.70]). Farm exposure during childhood was also associated with a reduced risk of sensitization to cat or timothy (OR = 0.60 [0.51-0.70]; OR=0.46 [0.41-0.51]). Studies investigating the effect of farm exposure in adult life could not be meta-analysed, and their results were inconsistent. Insufficient studies investigated food sensitization as an outcome to allow synthesis. The majority of studies included in this review investigated childhood farm exposure, finding evidence to support a protective childhood 'farm effect' against subsequent atopy. There is inconsistent evidence on the association between farm exposure in adulthood and allergic sensitization. Further studies are needed to tease out the exact exposures and timing associated with farming environments that protect against allergic disease.

Identification of early environmental risk factors for irritable bowel syndrome and dyspepsia

BACKGROUND

The role of childhood environment including exposure to infection via siblings and pets in irritable bowel syndrome (IBS) and dyspepsia is relatively unknown. We assessed proxy measures of microbial exposure in early childhood to assess if these are associated with IBS and functional dyspepsia in later life.

METHODS

Participants (n = 767, response rate = 53%) were a random population sample from Sydney, Australia who previously responded to a validated survey. IBS and functional dyspepsia were defined using Rome III criteria. Early environmental risk factors assessed included type of birth delivery, premature birth, breastfeeding, bedroom sharing, and pet exposure (the latter two then combined as early hygiene factors) up to 5 years of age. Post infectious IBS (PI-IBS) was assessed by development of IBS following gastroenteritis.

KEY RESULTS

In this sample, in adult life 17% developed IBS (of which 20% had PI-IBS) and 12% functional dyspepsia. Development of IBS was associated with childhood factors-a shorter duration of breastfeeding (odds ratios [OR] = 0.87, 95% CI: 0.78-0.97, p = 0.01), sharing a bedroom (OR = 1.89, 95% CI: 1.73-3.08, p = 0.01), exposure to a herbivore pet (OR = 1.65 (1.10, 2.48), p = 0.02), and hygiene factors (OR = 4.39; 95% CI: 1.89-10.21, p = 0.001). The sole factor associated with functional dyspepsia was exposure to a herbivore pet (1.79; 95% CI: 1.19-2.87, p = 0.02).

CONCLUSIONS & INFERENCES

Childhood environment factors, particularly bedroom sharing and pet exposure, combined with subsequent risk of microbial exposure are a risk factor for IBS in later life. These associations however need confirmation to rule out any risk of a type I error.

Intestinal microbial diversity during early-life colonization shapes long-term IgE levels

Microbial exposure following birth profoundly impacts mammalian immune system development. Microbiota alterations are associated with increased incidence of allergic and autoimmune disorders with elevated serum IgE as a hallmark. The previously reported abnormally high serum IgE levels in germ-free mice suggests that immunoregulatory signals from microbiota are required to control basal IgE levels. We report that germ-free mice and those with low-diversity microbiota develop elevated serum IgE levels in early life. B cells in neonatal germ-free mice undergo isotype switching to IgE at mucosal sites in a CD4 T-cell- and IL-4-dependent manner. A critical level of microbial diversity following birth is required in order to inhibit IgE induction. Elevated IgE levels in germ-free mice lead to increased mast-cell-surface-bound IgE and exaggerated oral-induced systemic anaphylaxis. Thus, appropriate intestinal microbial stimuli during early life are critical for inducing an immunoregulatory network that protects from induction of IgE at mucosal sites.

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Germ-free and mice with low-diversity microbiota develop high serum IgE levels

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B cells in germ-free mice undergo IgE class switch recombination at mucosal sites

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A diverse microbiota early in life is required to inhibit IgE induction

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Hyper IgE in germ-free mice leads to exaggerated oral-induced systemic anaphylaxis

Antibiotic treatments and microbes in the gut

Antibiotic therapies are important in combating disease-causing microorganisms and maintaining host health. It is widely accepted that exposure of the gut microbiota to antibiotics can lead to decreased susceptibility and the development of multi-drug-resistant disease-causing organisms, which can be a major clinical problem. It is also important to consider that antibiotics not only target pathogenic bacteria in the gut, but also can have damaging effects on the ecology of commensal species. This can reduce intrinsic colonization resistance and contribute to problems with antibiotic resistance, including lateral transfer of resistance genes. Our knowledge of the impact of antibiotic treatment on the ecology of the normal microbiota has been increased by recent advances in molecular methods and use of in vitro model systems to investigate the impact of antibiotics on the biodiversity of gut populations and the spread of antibiotic resistance. These highlight the need for more detailed structural and functional information on the long-term antibiotic-associated alterations in the gut microbiome, and spread of antibiotic resistance genes. This will be crucial for the development of strategies, such as targeted therapeutics, probiotics, prebiotics and synbiotics, to prevent perturbations in the gut microbiota, the restoration of beneficial species and improvements in host health.

The human microbiome. Early life determinant of health outcomes

The development of new technologies to isolate and identify microbial genomes has markedly increased our understanding of the role of microbiomes in health and disease. The idea, first proposed as part of the hygiene hypothesis, that environmental microbes influence the developmental trajectories of the immune system in early life, has now been considerably extended and refined. The abundant microbiota present in mucosal surfaces, especially the gut, is actively selected by the host through complex receptor systems that respond differentially depending on the molecular patterns presented to mucosal cells. Germ-free mice are more likely to develop allergic airway inflammation and show alterations in normal motor control and anxiety. These effects can be reversed by neonatal microbial recolonization but remain unchanged if recolonization occurs in adults. What emerges from these recent studies is the discovery of a complex, major early environmental determinant of lifetime human phenotypes. To change the natural course of asthma, obesity, and other chronic inflammatory conditions, active manipulation of the extensive bacterial, phage, and fungal metagenomes present in mucosal surfaces may be required, specifically during the developing years. Domesticating the human microbiome and adapting it to our health needs may be a challenge akin to, but far more complex than, the one faced by humanity when a few dozen species of plants and animals were domesticated during the transition between hunter-gatherer and sedentary societies after the end of the Pleistocene era.

Association between birthplace and current asthma: the role of environment and acculturation

OBJECTIVES

We evaluated associations between current asthma and birthplace among major racial/ethnic groups in the United States.

METHODS

We used multivariate logistic regression methods to analyze data on 102,524 children and adolescents and 255,156 adults in the National Health Interview Survey (2001-2009).

RESULTS

We found significantly higher prevalence (P < .05) of current asthma among children and adolescents (9.3% vs 5.1%) and adults (7.6% vs 4.7%) born in the 50 states and Washington, DC (US-born), than among those born elsewhere. These differences were among all age groups of non-Hispanic Whites, non-Hispanic Blacks, and Hispanics (excluding Puerto Ricans) and among Chinese adults. Non-US-born adults with 10 or more years of residency in the United States had higher odds of current asthma (odds ratio = 1.55; 95% confidence interval = 1.25, 1.93) than did those who arrived more recently. Findings suggested a similar trend among non-US-born children.

CONCLUSIONS

Current asthma status was positively associated with being born in the United States and with duration of residency in the United States. Among other contributing factors, changes in environment and acculturation may explain some of the differences in asthma prevalence.

The hygiene hypothesis in allergy and asthma: an update

PURPOSE OF REVIEW

It has been hypothesized that increased cleanliness, reduced family size, and subsequent decreased microbial exposure could explain the increases in global asthma prevalence. This review considers the recent evidence for and against the 'hygiene hypothesis'.

RECENT FINDINGS

Recent evidence does not provide unequivocal support for the hygiene hypothesis: the hygiene hypothesis specifically relates to atopic asthma, but some of the protective effects (e.g. farm exposures) appear to apply to both atopic and nonatopic asthma; asthma prevalence has begun to decline in some western countries, but there is little evidence that they have become less clean; Latin American countries with high infection rates have high asthma prevalence and the hygiene hypothesis relates to early-life exposures, but exposures throughout life may be important.

SUMMARY

There is a considerable body of evidence which warrants scepticism about the hygiene hypothesis. However, these anomalies contradict the 'narrow' version of it in which microbial pressure early in life protects against atopic asthma by suppressing T-helper 2 immune responses. It is possible that a more general version of the hygiene hypothesis is still valid, but the aetiologic mechanisms involved are currently unclear.

Case-control study of association of eosinophilic gastrointestinal disorders with Helicobacter pylori infection in Japan

Recent studies have suggested that decrease in Helicobacter pylori infection may predispose to allergic diseases. However, there are few reports of the relationships of eosinophilic gastrointestinal disorders (EGIDs), especially eosinophilic gastroenteritis (EGE), with H. pylori infection. We investigated the possible influence of H. pylori infection on EGIDs in Japanese patients. We performed a case-control study to investigate the prevalence of H. pylori infection in patients with EGIDs. Eighteen with eosinophilic esophagitis (EoE) and 22 with EGE were enrolled. For each patient, 3 age- and gender-matched normal controls (n = 120) were randomly selected from a population who received a medical check-up between April 2010 and December 2011 at the Shimane Institute of Health Science. The mean ages of the EoE and EGE patients were 50.9 ± 17 and 49.2 ± 20 years, respectively. Males were more frequently seen in the EoE group, while there was no significant gender difference in regard to EGE. Of the patients with EoE, 22.3% were infected with H. pylori, as compared to 55.5% of their age- and sex-matched normal controls. The odds ratio for EoE patients to have an H. pylori infection was 0.22 (p<0.05). In addition, 22.7% of the patients with EGE and 48.5% of their matched controls were infected with H. pylori, with odds ratio for EGE patients to have an H. pylori infection shown to be 0.31 (p<0.05). In conclusion, the prevalence of H. pylori infection was significantly lower in EGE and EoE patients in Japan as compared to normal control subjects.

Pathogenic bacteria colonizing the airways in asymptomatic neonates stimulates topical inflammatory mediator release

RATIONALE

Bacterial colonization of neonatal airways with the pathogenic bacterial species, Moraxella catarrhalis, Streptococcus pneumoniae, and Haemophilus influenzae, is associated with later development of childhood asthma.

OBJECTIVES

To study a possible association between colonization with pathogenic bacterial strains and the immune signature of the upper airways in healthy neonates.

METHODS

A total of 20 cytokines and chemokines were quantified in vivo in the airway mucosal lining fluid of 662 neonates from the Copenhagen Prospective Study of Asthma in Childhood 2010 birth cohort. Colonization of the hypopharynx with M. catarrhalis, S. pneumoniae, H. influenzae, and Staphylococcus aureus was assessed simultaneously. The association between immune signatures and bacterial colonization or noncolonized controls was analyzed using conventional statistical methods supplemented by a multivariate approach for pattern identification.

MEASUREMENTS AND MAIN RESULTS

Colonization with M. catarrhalis and H. influenzae induced a mixed T helper cell (Th) type 1/Th2/Th17 response with high levels of IL-1β (M. catarrhalis, P = 2.2 × 10(-12); H. influenzae, P = 7.1 × 10(-10)), TNF-α (M. catarrhalis, P = 1.5 × 10(-9); H. influenzae, P = 5.9 × 10(-7)), and macrophage inflammatory protein-1β (M. catarrhalis, P = 1.6 × 10(-11); H. influenzae, P = 2.7 × 10(-7)). S. aureus colonization demonstrated a Th17-promoting profile with elevated IL-17 levels (P = 1.6 × 10(-24)). S. pneumoniae colonization was not significantly associated with any of the mediators.

CONCLUSIONS

M. catarrhalis and H. influenzae colonization of the airways of asymptomatic neonates is associated with an inflammatory immune response of the airway mucosa, which may result in chronic inflammation.

A randomized trial of Lactobacillus plantarum CJLP133 for the treatment of atopic dermatitis

BACKGROUND

There have been considerable disagreements regarding the therapeutic effects of probiotics in atopic dermatitis (AD). We performed this study to examine whether the oral administration of Lactobacillus plantarum CJLP133 improves pediatric AD.

METHODS

In a randomized, double-blind, placebo-controlled study, either L. plantarum CJLP133 at a dosage of 0.5 × 10(10) colony-forming units or placebo in children aged 12 months to 13 yr was given twice a day for 12 wk. SCOring of Atopic Dermatitis (SCORAD) scores, eosinophil counts, serum total IgE, and cytokines were evaluated.

RESULTS

Forty-four of 58 patients in the probiotic group and 39 of 60 patients in the placebo group completed the study. The SCORAD score at week 14 was lower in the probiotic group than in the placebo group (p = 0.044). The mean change in the SCORAD score from weeks 2 to 14 was 9.1 in the probiotic group, which was greater than the mean change of 1.8 in the placebo group (p = 0.004). No statistical differences in the total use of topical corticosteroids were found between two groups (p = 0.815). In the probiotic group, the total eosinophil count was significantly lower at the end of the intervention compared to the baseline measurements (p = 0.023). Logarithmic IFN-γ and IL-4 were significantly decreased by the end of the intervention compared to baseline measurements in the probiotic group (p < 0.001 and 0.049).

CONCLUSIONS

Our results suggest that supplementation with probiotic L. plantarum CJLP133 is beneficial in the treatment of pediatric AD.

Antibiotic use in infants in the first year of life in five European countries

AIM

To assess in infants the number of illness episodes treated with antibiotics and prescription rates in five European countries.

METHODS

This study was embedded in a multicenter nutritional intervention study and was conducted in five European countries. Infants were followed until 1 year of age. Illness episodes and prescriptions of systemic antibiotics were recorded by the parents.

RESULTS

Illness episodes were caused by upper respiratory tract infections (URTIs) in 55-64% and by otitis media (OM) in 2-6.8%. URTIs were statistically significant and more frequently treated with antibiotics in Italy (18.8%), and less frequently in Switzerland (1.4%). OM was statistically significant and less frequently treated with antibiotics in the Netherlands (55%) when compared to Italy (82%). The antibiotic prescription rate varied between countries, ranging from 0.2 to 1.3 prescriptions per infant per year.

CONCLUSIONS

As the frequency of illness episodes did not differ between countries, other factors, such as physician's attitude, parental pressure or other socio-economic determinants, most likely play a role in antibiotic prescribing habits in the first year of life.

Effect of endotoxin and allergens on neonatal lung function and infancy respiratory symptoms and eczema

BACKGROUND

Exposure to endotoxin and allergens in house dust has been found to be associated with childhood wheeze and asthma. Neonatal lung function is rarely examined in relation to this exposure.

OBJECTIVES

To assess the association between exposure to endotoxin, house dust mite and cat allergens and neonatal lung function, and respiratory symptoms and eczema in infancy.

METHODS

In the Wheezing Illnesses Study Leidsche Rijn (WHISTLER) birth cohort study, levels of endotoxin, house dust mite allergens, and cat allergen have been measured in dust samples collected in the child's home. Lung function was measured before age 2 months, and respiratory symptoms and eczema were recorded in a daily diary during the first year of life. Associations of lung function (N = 302), respiratory symptoms (N = 361), and eczema (N = 342) with endotoxin and allergen levels have been studied by means of linear and logistic regression, respectively.

RESULTS

Mattress dust endotoxin was associated with a significant increase in neonatal respiratory compliance [adjusted mean difference (95% confidence interval) 2.31 (0.33; 4.29) ml/kPa per interquartile range increase in exposure] and a non-significant decrease in neonatal airway resistance [0.32 (-0.77; 0.14) kPa/l/s]. There were no associations between allergen exposure and neonatal lung function and respiratory symptoms.

CONCLUSIONS

Environmental exposure to endotoxin may have an important role in the development of lung function.

Asthma and allergies in Jamaican children aged 2-17 years: a cross-sectional prevalence survey

OBJECTIVE

To determine the prevalence and severity of asthma and allergies as well as risk factors for asthma among Jamaican children aged 2-17 years.

DESIGN

A cross-sectional, community-based prevalence survey using the International Study of Asthma and Allergies in Childhood questionnaire. The authors selected a representative sample of 2017 children using stratified, multistage cluster sampling design using enumeration districts as primary sampling units.

SETTING

Jamaica, a Caribbean island with a total population of approximately 2.6 million, geographically divided into 14 parishes.

PARTICIPANTS

Children aged 2-17 years, who were resident in private households. Institutionalised children such as those in boarding schools and hospitals were excluded from the survey.

PRIMARY AND SECONDARY OUTCOME MEASURES

The prevalence and severity of asthma and allergy symptoms, doctor-diagnosed asthma and risk factors for asthma.

RESULTS

Almost a fifth (19.6%) of Jamaican children aged 2-17 years had current wheeze, while 16.7% had self-reported doctor-diagnosed asthma. Both were more common among males than among females. The prevalence of rhinitis, hay fever and eczema among children was 24.5%, 25% and 17.3%, respectively. Current wheeze was more common among children with rhinitis in the last 12 months (44.3% vs 12.6%, p<0.001), hay fever (36.8% vs 13.8%, p<0.001) and eczema (34.1% vs 16.4%, p<0.001). Independent risk factors for current wheeze (ORs, 95% CI) were chest infections in the first year of life 4.83 (3.00 to 7.77), parental asthma 4.19 (2.8 to 6.08), rhinitis in the last 12 months 6.92 (5.16 to 9.29), hay fever 4.82 (3.62 to 6.41), moulds in the home 2.25 (1.16 to 4.45), cat in the home 2.44 (1.66 to 3.58) and dog in the home 1.81 (1.18 to 2.78).

CONCLUSIONS

The prevalence of asthma and allergies in Jamaican children is high. Significant risk factors for asthma include chest infections in the first year of life, a history of asthma in the family, allergies, moulds and pets in the home.

Expanding the hygiene hypothesis: early exposure to infectious agents predicts delayed-type hypersensitivity to Candida among children in Kilimanjaro

Background

Multiple lines of evidence suggest that infections in early life prevent the development of pathological immune responses to allergens and autoantigens (the hygiene hypothesis). Early infections may also affect later immune responses to pathogen antigen.

Methods

To evaluate an association between early infections and immune responses to pathogen antigen, delayed-type hypersensitivity (DTH) to Candida albicans was evaluated among 283 2- to 7-year-old children in Kilimanjaro, Tanzania. A questionnaire and physical examination were used to characterize variables reflecting early exposure to infectious agents (family size, house construction materials, BCG vaccination, hospitalization history). Logistic regression was used to evaluate the association between early exposure to infectious agents and DTH to C. albicans.

Results

Triceps skinfold thickness (OR: 1.11; 95% CI: 1.01, 1.22) and age (OR: 1.27; 95% CI: 1.04, 1.55) were positively associated with DTH to C. albicans. Adjusted for age and sex, large family size (OR: 2.81; 95% CI: 1.04, 7.61), BCG vaccination scar (OR: 3.10; 95% CI: 1.10, 8.71), and hospitalization during infancy with an infectious disease (OR: 4.67; 95% CI: 1.00, 21.74) were positively associated with DTH to C. albicans.

Conclusions

Early life infections were positively associated with later DTH to C. albicans. This result supports an expansion of the hygiene hypothesis to explain not only pathological immune responses to allergens, but also appropriate immune responses to pathogens. Immune system development may be responsive to early infections as an adaptive means to tailor reactivity to the local infectious disease ecology.

The impact of bacterial infection on mast cell degranulation

In developed countries, the prevalence of allergy is on the rise. Although the causes are unknown, it seems that (1) the disappearance of microbiota may play a role in the increase of allergies and (2) exposure to bacterial infections during childhood decreases the incidence of allergies. Although several cell types are involved in the development of allergy, mast cells play a major role in orchestrating inflammation. Upon activation, mast cell secretory granules fuse with the plasma membrane, resulting in the release of a number of inflammatory mediators. In addition to allergy, mast cells contribute to the innate immune response against a variety of bacteria. This is accomplished through the secretion of cytokines and other soluble mediators. Interestingly, there is growing evidence that mast cells exposed to bacteria down-regulate degranulation in response to IgE/Allergen stimulation. This inhibitory effect seems to require direct contact between bacteria and mast cells, but the intracellular mechanism by which bacterial contact suppresses allergic responses is unknown. Here, we review different aspects of mast cell physiology and discuss hypotheses as to how bacteria may influence mast cell degranulation.

Atopy is a risk factor for adult asthma in urban community of Southwestern Nigeria

RATIONALE

Factors affecting asthma course are not clearly elucidated in urban communities in developing countries. Furthermore, the interaction between factors such as atopy, environmental exposure, urbanization, and helminthic infections in modulating asthma have not been well investigated.

OBJECTIVES

To determine factors, which affect asthma in adults being evaluated at urban tertiary health center of Southwestern part of Nigeria.

MATERIALS AND METHODS

A random sample of 24 (12 males, 12 females) consecutive asthmatics seen in the Outpatient Pulmonary Clinic of University College Hospital of Ibadan and 27 (13 males, 14 females) age and gender-matched controls underwent evaluation, which included blood tests for eosinophils, serum IgE, allergy skin tests to eight common environmental allergens, and spirometry. The modified version of the questionnaire of the International study of Asthma and Allergies in Children (ISAAC) Phase III used by the same study group of researchers in Nigeria was used to assess the asthma symptoms. Wilcoxon sign-rank tests were used to compare eosinophil counts, percentage eosinophils, and allergic skin test between the two groups, while paired t test was used to compare spirometry variables.

RESULTS

Asthmatics had significantly more positive skin reaction to house dust mite and mould than controls (P<0.05). Total serum IgE was also significantly higher in asthmatics than in controls (mean 210 vs 60 IU/mL; P=0.003). However, no significant differences were observed in total eosinophil counts. No significant difference in the degree of intestinal helminthes infection in the two groups, which means stool parasitism was similar. FEV(1) % was significantly lower in asthmatics (P=0.02) but FEV(1) was similar between the two groups (P=0.02).

CONCLUSION

The elevated levels of IgE and positive skin reactions to some of the common environmental allergens suggests an important role of atopy in the expression of asthma in this developing country's urban setting. Intestinal parasites were seen in both, control and asthma subjects, but appear not to play any role in the course of asthma, so also is the blood group, genotype and G6PD status.

The risk factors and quality of life in children with allergic rhinitis in relation to seasonal attack patterns

A questionnaire survey was conducted to examine whether risk factors and allergic rhinitis (AR)-related quality of life (QOL) were different among children with different seasonal patterns of AR. Participants were students enrolled in elementary and middle schools in Taipei County, Taiwan. Using moving average and principal component analysis, children with current AR were grouped by attack seasons. The effects of personal and environmental factors on AR seasonality were assessed by logistic regression models. AR severity and AR-related QOL were compared within AR seasonal subtypes. Among 4221 children who completed the questionnaire, 1144 and 1605 children were current AR cases and healthy controls, respectively. Four AR subtypes were categorised as follows: perennial, spring, summer/fall, and winter. Age, gender, parental education, maternal passive smoking during pregnancy, breast feeding, and mouldy walls were found to contribute differentially to different AR subtypes. Children suffering from perennial and winter AR were found to have more severe symptoms and significantly lower QOL score compared with other subtypes. Specific personal and environmental risk factors could contribute to different AR seasonal subtypes. Active allergen avoidance and symptomatic treatment should be the focus of management aiming to improve the QOL among children with perennial and winter subtype.

Effects of Lactobacillus rhamnosus GG supplementation on cow's milk allergy in a mouse model

BACKGROUND

Cow's milk allergy (CMA) is one of the most prevalent human food-borne allergies, particularly in infants and young children from developed countries. Our study aims to evaluate the effects of Lactobacillus rhamnosus GG (LGG) administration on CMA development using whole cow's milk proteins (CMP) sensitized Balb/C mice by two different sensitization methods.

METHODS

LGG supplemented mice were either sensitized orally with CMP and cholera toxin B-subunit (CTB) as adjuvant, or intraperitoneally (IP) with CMP but without the adjuvant. Mice were then orally challenged with CMP and allergic responses were accessed by monitoring hypersensitivity scores, measuring the levels of CMP-specific immunoglobulins (IgG1, IgG2a and IgG) and total IgE from sera, and cytokines (IL-4 and IFN-γ) from spleen lysates.

RESULTS

Sensitization to CMP was successful only in IP sensitized mice, but not in orally sensitized mice with CMP and CTB. Interestingly, LGG supplementation appeared to have reduced cow's milk allergy (CMA) in the IP group of mice, as indicated by lowered allergic responses.

CONCLUSIONS

Adjuvant-free IP sensitization with CMP was successful in inducing CMA in the Balb/C mice model. LGG supplementation favourably modulated immune reactions by shifting Th2-dominated trends toward Th1-dominated responses in CMP sensitized mice. Our results also suggest that oral sensitization by the co-administration of CMP and CTB, as adjuvant, might not be appropriate to induce CMA in mice.

Asthma phenotypes in adults and clinical implications

It is becoming increasingly recognized that asthma is a heterogeneous disease, whether based on clinical factors, including the patient's age at diagnosis, symptom spectrum and treatment response, triggering factors, or the level and type of inflammation. Attempts to analyze the importance of these characteristics to the clinical presentation of asthma have led to the appreciation of numerous separate and overlapping asthma phenotypes. However, these approaches are 'biased' and based on the clinician/scientist's own experience. Recently, unbiased approaches have also been attempted using both molecular and statistical tools. Early results from these approaches have supported and expanded on the clinician's concepts. However, until specific biologic markers are identified for any of these proposed phenotypes, the definitive nature of any phenotype will remain speculative.

The effect of Kawasaki disease on childhood allergies - a sibling control study

OBJECTIVE

Kawasaki disease (KD) is a multisystem inflammatory vasculitis of childhood, with widespread T-helper cell type 1 immune activation. We hypothesize that children who suffered from KD will have a lower risk of developing allergic diseases.

STUDY DESIGN

This was a cross-sectional study, recruiting children with a history of KD, together with well sibling controls. All children underwent the standardized core ISAAC questionnaire for allergy, physical examination and skin prick test evaluation. McNemar's test was employed to evaluate the effect of Kawasaki disease on allergy. Multivariable analysis based on mixed-effects logistic regression model was used to adjust for potential confounding effect of age and gender.

RESULTS

One hundred and eighty-six children (93 KD sibling pairs) completed the above evaluation. Allergic rhinitis was more common in patients with KD (crude OR 2.40; 95% CI 1.11-5.62, p=0.024) when compared with controls. The effect was further intensified after accounting for the potential confounding effect of age and gender (adjusted OR=2.90; 95% CI 1.27-6.60). Children in whom KD occurred beyond the age of 12 months had more allergic rhinitis (crude OR 4.00, 95% CI 1.29-16.44, p=0.012), 'any' allergies (crude OR 3.75, 95% CI 1.19-15.52, p=0.019) and Blomia tropicalis sensitization (crude OR 2.57, 95% CI 1.02-7.28, p=0.043) when compared with their sibling controls. Interestingly, children in whom KD course resulted in no coronary artery abnormalities have more allergic rhinitis (crude OR 8.50, 95% CI 2.02-75.85, p=0.003) and 'any' allergies (crude OR 5.00, 95% CI 1.41-26.94, p=0.011), when compared with their sibling controls.

CONCLUSION

Kawasaki disease may be a risk factor for subsequent allergic diseases. We postulate that KD occurs more frequently in children at risk of immune disequilibrium, with an abnormal inflammatory response initially, and subsequently more allergic manifestations.

Reduced diversity of the intestinal microbiota during infancy is associated with increased risk of allergic disease at school age

BACKGROUND

Changes in the human microbiome have been suggested as a risk factor for a number of lifestyle-related disorders, such as atopic diseases, possibly through a modifying influence on immune maturation in infancy.

OBJECTIVES

We aimed to explore the association between neonatal fecal flora and the development of atopic disorders until age 6 years, hypothesizing that the diversity of the intestinal microbiota influences disease development.

METHODS

We studied the intestinal microbiota in infants in the Copenhagen Prospective Study on Asthma in Childhood, a clinical study of a birth cohort of 411 high-risk children followed for 6 years by clinical assessments at 6-month intervals, as well as at acute symptom exacerbations. Bacterial flora was analyzed at 1 and 12 months of age by using molecular techniques based on 16S rRNA PCR combined with denaturing gradient gel electrophoresis, as well as conventional culturing. The main outcome measures were the development of allergic sensitization (skin test and specific serum IgE), allergic rhinitis, peripheral blood eosinophil counts, asthma, and atopic dermatitis during the first 6 years of life.

RESULTS

We found that bacterial diversity in the early intestinal flora 1 and 12 months after birth was inversely associated with the risk of allergic sensitization (serum specific IgE P = .003; skin prick test P = .017), peripheral blood eosinophils (P = .034), and allergic rhinitis (P = .007). There was no association with the development of asthma or atopic dermatitis.

CONCLUSIONS

Reduced bacterial diversity of the infant's intestinal flora was associated with increased risk of allergic sensitization, allergic rhinitis, and peripheral blood eosinophilia, but not asthma or atopic dermatitis, in the first 6 years of life. These results support the general hypothesis that an imbalance in the intestinal microbiome is influencing the development of lifestyle-related disorders, such as allergic disease.

Association of allergic sensitization with infectious diseases burden in Roma and non-Roma children

The hypothesis whether exposure to certain infections protects from atopy remains equivocal. To further investigate this, we compared serologic markers of infection and allergic sensitization prevalence in Roma children, who live under unfavorable hygienic conditions that facilitate the spread of infections, and non-Roma children who live in the same area. Analyses included 98 Roma and 118 non-Roma children. Serum IgG antibodies for 13 foodborne- airborne- and bloodborne infectious agents were determined, and a cumulative index of exposure was calculated by adding one point for each positive infection. Specific serum IgE to certain common food- and aero-allergens was also tested. and positivity to any of them was defined as indication of atopy. Roma children were found significantly more seropositive for T. gondii, Hepatitis A, H. pylori, HSV-1, CMV, and Hepatitis B (p < 0.0001). Non-Roma children were found more seropositive for RSV and M. pneumonia (p < 0.0001). Regarding the overall prevalence of atopy or the specific IgE responses to the allergens tested, no statistically significant differences were found between Roma and non-Roma children. A positive association of the cumulative index of exposure to infections with atopy was found in the non-Roma children (OR: 1.38, 95% CI: 1.08-1.75, p = 0.01) and in the total population (OR: 1.42, 95% CI: 1.11-1.83, p = 0.01). Regarding the specific infectious agents tested, a statistically significant positive association of atopy with seropositivity was found for M. pneumoniae in the non-Roma children (OR: 3.93, 95% CI: 1.39) as well as in the total population studied (OR: 2.83, 95% CI: 1.32-6.07, p = 0.01). Despite the higher burden of exposure to the battery of the infectious agents tested among Roma children, no protective effect for allergic disease development was evident. On the contrary, a positive association of exposure to infections with evidence of atopy was found, especially evident in the non-Roma children.

Antibiotic exposure by 6 months and asthma and allergy at 6 years: Findings in a cohort of 1,401 US children

Many studies have reported that antibiotic use may be associated with increased risk of childhood asthma. Respiratory tract infections in small children may be difficult to distinguish from early symptoms of asthma, and studies may have been confounded by "protopathic" bias, where antibiotics are used to treat early symptoms of asthma. These analyses of a cohort including 1,401 US children assess the association between antibiotic use within the first 6 months of life and asthma and allergy at 6 years of age between 2003 and 2007. Antibiotic exposure was associated with increased risk of asthma (adjusted odds ratio = 1.52, 95% confidence interval (CI): 1.07, 2.16). The odds ratio if asthma was first diagnosed after 3 years of age was 1.66 (95% CI: 0.99, 2.79) and, in children with no history of lower respiratory infection in the first year of life, the odds ratio was 1.66 (95% CI: 1.12, 3.46). The adverse effect of antibiotics was particularly strong in children with no family history of asthma (odds ratio = 1.89, 95% CI: 1.00, 3.58) (P(interaction) = 0.03). The odds ratio for a positive allergy blood or skin test was 1.59 (95% CI: 1.10, 2.28). The results show that early antibiotic use was associated with asthma and allergy at 6 years of age, and that protopathic bias was unlikely to account for the main findings.

Exposure to dogs is associated with a decreased tumour necrosis factor-α-producing capacity in early life

BACKGROUND

It appears that contacts with furred animals early in life and already during gestation contribute to the immunological development in humans, but the mechanisms and relevant exposures are not clear.

OBJECTIVE

To investigate whether exposure to animals during pregnancy and the first year of life is associated with early immune development, determined as stimulated cytokine responses of children at birth and at age 1 year.

METHODS

Cord blood (n=228) and peripheral venous blood (n=200) samples 1 year after birth were collected and stimulated with Gram-positive superantigen Staphylococcal enterotoxin B, Gram-negative bacterial lipopolysaccharide (LPS) and the combination of mitogenic phorbol 12-myristate 13-acetate and calcium ionophore ionomycin (P/I) for 24 and 48 h. TNF-α, IFN-γ, IL-5, IL-8 and IL-10 responses were measured by ELISA. For each cytokine, the time-point with the highest response was chosen for further analyses. Animal contacts were surveyed by self-administered questionnaires.

RESULTS

Dog ownership was associated with decreased TNF-α-producing capacity at birth (P/I: median 841 vs. 881 pg/10(6) WBC, P=0.05) and 1 year after birth (P/I: 1290 vs. 1530, P=0.01; LPS: 425 vs. 508, P=0.02). Associations remained significant after adjustment for potential confounders. Cat ownership was not associated with cytokine production.

CONCLUSION

Having a dog in the household in infancy and already during pregnancy may be associated with reduced innate immune responses in early childhood. The observed attenuation of cytokine production may help in preventing exaggerated immune responses against harmless antigens later in life. Thus, intensive exposure to dogs in early life may be beneficial during normal immune maturation.