Early childhood infectious diseases and the development of asthma up to school age: a birth cohort study

Bronchial Asthma and COVID-19: Etiology, Pathological Triggers, and Therapeutic Considerations

Bronchial asthma (BA) continues to be a difficult disease to diagnose. Various factors have been described in the development of BA, but to date, there is no clear evidence for the etiology of this chronic disease. The emergence of COVID-19 has contributed to the pandemic course of asthma and immunologic features. However, there are no unambiguous data on asthma on the background and after COVID-19. There is correlation between various trigger factors that provoke the development of bronchial asthma. It is now obvious that the SARS-CoV-2 virus is one of the provoking factors. COVID-19 has affected the course of asthma. Currently, there is no clear understanding of whether asthma progresses during or after COVID-19 infection. According to the results of some studies, a significant difference was identified between the development of asthma in people after COVID-19. Mild asthma and moderate asthma do not increase the severity of COVID-19 infection. Nevertheless, oral steroid treatment and hospitalization for severe BA were associated with higher COVID-19 severity. The influence of SARS-CoV-2 infection is one of the protective factors. It causes the development of severe bronchial asthma. The accumulated experience with omalizumab in patients with severe asthma during COVID-19, who received omalizumab during the pandemic, has strongly suggested that continued treatment with omalizumab is safe and may help prevent the severe course of COVID-19. Targeted therapy for asthma with the use of omalizumab may also help to reduce severe asthma associated with COVID-19. However, further studies are needed to prove the effect of omalizumab. Data analysis should persist, based on the results of the course of asthma after COVID-19 with varying degrees of severity.

Natural killer cell-mediated contact dermatitis-like reaction induced by treatment with TLR3 ligand poly(I:C)

INTRODUCTION

Poly(I:C) is recognised by endosomal Toll-like receptor 3 (TLR3) and activates cytotoxic CD8(+) lymphocytes and natural killer (NK) cells. It has been shown that the viral TLR3 agonist induces robust and long-lasting T-cell-mediated responses. In addition, TLR3 modulates the contact hypersensitivity reaction.

OBJECTIVE

This study aimed to determine whether poly(I:C) injection can induce NK-mediated hapten reactivity in mice.

METHODS

Mice were treated with poly(I:C), and their response to dinitrofluorobenzene hapten was measured by assessing ear swelling and serum interferon gamma (IFN-γ) production. Adoptive cell transfer and cell sorting were used to investigate the mechanism of the reaction, and the phenotype of poly(I:C)-activated liver NK cells was determined by flow cytometry analysis.

RESULTS

The results showed that poly(I:C) administration increased ear swelling, serum IFN-γ levels and the response to hapten in both immunocompetent and T- and B-cell-deficient mice. Only liver poly(I:C)-activated DX5(+) NK cells were able to transfer reactivity to hapten into a naive recipient. Induction of liver NK cells after poly(I:C) administration was TLR3/TRIF- and IFN-γ-dependent, interleukin 12-independent, and not modulated by MyD88.

CONCLUSION

This study provides new insights into how poly(I:C) stimulates NK-mediated reactivity to hapten and suggests that liver NK cells may modulate the immune response to non-pathogenic factors during viral infection.

GEMA 5.3. Spanish Guideline on the Management of Asthma

The Spanish Guideline on the Management of Asthma, better known by its acronym in Spanish GEMA, has been available for more than 20 years. Twenty-one scientific societies or related groups both from Spain and internationally have participated in the preparation and development of the updated edition of GEMA, which in fact has been currently positioned as the reference guide on asthma in the Spanish language worldwide. Its objective is to prevent and improve the clinical situation of people with asthma by increasing the knowledge of healthcare professionals involved in their care. Its purpose is to convert scientific evidence into simple and easy-to-follow practical recommendations. Therefore, it is not a monograph that brings together all the scientific knowledge about the disease, but rather a brief document with the essentials, designed to be applied quickly in routine clinical practice. The guidelines are necessarily multidisciplinary, developed to be useful and an indispensable tool for physicians of different specialties, as well as nurses and pharmacists. Probably the most outstanding aspects of the guide are the recommendations to: establish the diagnosis of asthma using a sequential algorithm based on objective diagnostic tests; the follow-up of patients, preferably based on the strategy of achieving and maintaining control of the disease; treatment according to the level of severity of asthma, using six steps from least to greatest need of pharmaceutical drugs, and the treatment algorithm for the indication of biologics in patients with severe uncontrolled asthma based on phenotypes. And now, in addition to that, there is a novelty for easy use and follow-up through a computer application based on the chatbot-type conversational artificial intelligence (ia-GEMA).

Epidemiology and Immunopathogenesis of Virus Associated Asthma Exacerbations

Asthma is a common airway disease, affecting millions of people worldwide. Although most asthma patients experience mild symptoms, it is characterized by variable airflow limitation, which can occasionally become life threatening in the case of a severe exacerbation. The commonest triggers of asthma exacerbations in both children and adults are viral infections. In this review article, we will try to investigate the most common viruses triggering asthma exacerbations and their role in asthma immunopathogenesis, since viral infections in young adults are thought to trigger the development of asthma either right away after the infection or at a later stage of their life. The commonest viral pathogens associated with asthma include the respiratory syncytial virus, rhinoviruses, influenza and parainfluenza virus, metapneumovirus and coronaviruses. All these viruses exploit different molecular pathways to infiltrate the host. Asthmatics are more prone to severe viral infections due to their unique inflammatory response, which is mostly characterized by T2 cytokines. Unlike the normal T1 high response to viral infection, asthmatics with T2 high inflammation are less potent in containing a viral infection. Inhaled and/or systematic corticosteroids and bronchodilators remain the cornerstone of asthma exacerbation treatment, and although many targeted therapies which block molecules that viruses use to infect the host have been used in a laboratory level, none has been yet approved for clinical use. Nevertheless, further understanding of the unique pathway that each virus follows to infect an individual may be crucial in the development of targeted therapies for the commonest viral pathogens to effectively prevent asthma exacerbations. Finally, biologic therapies resulted in a complete change of scenery in the treatment of severe asthma, especially with a T2 high phenotype. All available data suggest that monoclonal antibodies are safe and able to drastically reduce the rate of viral asthma exacerbations.

Association between urban garbage exposure and allergic diseases among sanitation practitioners: A cross-sectional study

Background

The prevalence of allergic diseases has increased significantly in China over the last few decades, and there have been very few reports of allergic diseases in certain occupational specialties, with almost no reports among sanitation workers.

Objective

Our objective was to investigate the prevalence of allergic diseases and the prevalence of common allergen sensitization in the population engaged in sanitation, and to try to answer the connection between urban garbage waste exposure and the development of allergic diseases.

Methods

We conducted a cross-sectional survey of people working in sanitation-related jobs in Liwan District, Guangzhou, China. A total of 893 people completed the questionnaire for this study, and 500 of them were further screened and tested for allergens specific IgE and IgG4. Combining the questionnaire and test results, we investigated the incidence of allergy disorders and patterns of sensitization to allergens in this community, and evaluated the presence of occupational-related risk factors in this particular population.

Results

Of the 893 sanitation workers, 166 (18.59%) self-reported allergic diseases, predominantly suffering from allergic rhinitis (AR) (n = 98, 10.97%), followed by drug allergy (n = 31, 3.47%), atopic dermatitis (n = 27, 3.02%), food allergy (n = 21, 2.35%), and asthma (n = 9, 1.00%), in that order. In addition to dust mites (32.20%), which had the highest sensitization rate, the subject population had relatively high sensitization rates to ragweed (7.00%) and moulds mixture (8.20%) when compared with the rates of sensitization to moulds and ragweed in the general population; the top 3 sIgG4 positivity rates were egg (50.00%), milk (10.20%), and soybean (9.40%). The prevalence of self-reported AR was higher in office managers (the control group) than in cleaning staff (the exposed group), but there was no difference in sIgE positivity for serum allergens between the 2 groups. The chance of having AR may increase with management positions (crude OR 2.20, 95% CI 1.38-3.50), P = 0.001).

Conclusion

This is the first study to investigate the prevalence of allergy illnesses in the sanitation workforce in mainland China. We identified a community of real sanitation workers with high ragweed and mycobacterial sensitization rates. Urban cleaning may be protective factor against AR at the symptom level, but the serological results did not show this to be the case.

Prevalence, Management, and Risk Factors of Asthma Among School-Age Children in Yogyakarta, Indonesia

Purpose

Childhood asthma in developing countries has been increasing, but underdiagnosed and undertreated. We reported prevalence, management, and risk factors of asthma among school-age children in Yogyakarta, Indonesia.

Patients and Methods

We recruited children aged 6-7 years and 13-14 years attending schools in all districts in Yogyakarta, Indonesia. The schools were randomly selected via cluster random sampling. We used the Indonesian version of the Global Asthma Network (GAN) questionnaire, and the methodology employed by this study was in accordance with the GAN's protocol.

Results

A total of 2106 children aged 6-7 years and 3142 adolescents aged 13-14 years were eligible for analysis. The prevalence of current wheeze in children and adolescents was similar, which was 4.6%. Inhalation therapy was reported in <30% of those with asthma. Risk factors for current wheeze in children were wheezing in infancy period, ever had pneumonia, the house was passed by trucks every day, and fast-food consumption in the previous 12 months; whereas exclusive breastfeeding for more than 6 months decreased the risk of current wheeze. In adolescence, obesity, consumption of fast food once or twice a week, and paracetamol in the previous 12 months increased the risk of current wheeze.

Conclusion

The prevalence of current wheeze in children and adolescents in Indonesia was quite low. The use of inhalation therapy was limited. Respiratory problems during infancy, environmental, and nutritional factors play a role in the development of asthma.

Prevalence and determinants of wasting of under-5 children in Bangladesh: Quantile regression approach

BACKGROUND

Wasting is perhaps one of the signs of malnutrition that has been linked to the deaths of children suffering from malnutrition. As a result, understanding its correlations and drivers is critical. Using quantile regression analysis, this research aims to contribute to the discussion on under-5 malnutrition by analyzing the predictors of wasting in Bangladesh.

METHODS AND MATERIALS

The dataset was extracted from the 2017-18 Bangladesh demographic and health survey (BDHS) data. The weight-for-height (WHZ) z-score based anthropometric indicator was used in the study as the target variable. The weighted sample constitutes 8,334 children of under-5 years. However, after cleaning the missing values, the analysis is based on 8,321 children. Sequential quantile regression was used for finding the contributing factors.

RESULTS

The findings of this study depict that the prevalence of wasting in children is about 8 percent and only approximately one percent of children are severely wasted in Bangladesh. Age, mother's BMI, and parental educational qualification, are all major factors of the WHZ score of a child. The coefficient of the female child increased from 0.1 to 0.2 quantiles before dropping to 0.75 quantile. For a child aged up to three years, the coefficients have a declining tendency up to the 0.5 quantile, then an increasing trend. Children who come from the richest households had 16.3%, 3.6%, and 15.7% higher WHZ scores respectively than children come from the poorest households suggesting that the risk of severe wasting in children under the age of five was lower in children from the wealthiest families than in children from the poorest families. The long-term malnutrition indicator (wasting) will be influenced by the presence of various childhood infections and vaccinations. Furthermore, a family's economic position is a key determinant in influencing a child's WHZ score.

CONCLUSIONS

It is concluded that socioeconomic characteristics are correlated with the wasting status of a child. Maternal characteristics also played an important role to reduce the burden of malnutrition. Thus, maternal nutritional awareness might reduce the risk of malnutrition in children. Moreover, the findings disclose that to enrich the nutritional status of children along with achieving Sustainable Development Goal (SDG)-3 by 2030, a collaborative approach should necessarily be taken by the government of Bangladesh, and non-governmental organizations (NGOs) at the community level in Bangladesh.

Early-life respiratory tract infections and the risk of school-age lower lung function and asthma: a meta-analysis of 150 000 European children

BACKGROUND

Early-life respiratory tract infections might affect chronic obstructive respiratory diseases, but conclusive studies from general populations are lacking. Our objective was to examine if children with early-life respiratory tract infections had increased risks of lower lung function and asthma at school age.

METHODS

We used individual participant data of 150 090 children primarily from the EU Child Cohort Network to examine the associations of upper and lower respiratory tract infections from age 6 months to 5 years with forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, forced expiratory flow at 75% of FVC (FEF75%) and asthma at a median (range) age of 7 (4-15) years.

RESULTS

Children with early-life lower, not upper, respiratory tract infections had a lower school-age FEV1, FEV1/FVC and FEF75% (z-score range: -0.09 (95% CI -0.14- -0.04) to -0.30 (95% CI -0.36- -0.24)). Children with early-life lower respiratory tract infections had a higher increased risk of school-age asthma than those with upper respiratory tract infections (OR range: 2.10 (95% CI 1.98-2.22) to 6.30 (95% CI 5.64-7.04) and 1.25 (95% CI 1.18-1.32) to 1.55 (95% CI 1.47-1.65), respectively). Adjustment for preceding respiratory tract infections slightly decreased the strength of the effects. Observed associations were similar for those with and without early-life wheezing as a proxy for early-life asthma.

CONCLUSIONS

Our findings suggest that early-life respiratory tract infections affect development of chronic obstructive respiratory diseases in later life, with the strongest effects for lower respiratory tract infections.

Early-Life Exposure of Pigs to Topsoil Alters miRNA and mRNA Expression in Peripheral Blood Mononuclear Cells

Exposure to less-hygienic conditions during early childhood has been associated with stimulation and development of the immune system. A recent study indicated that exposure of piglets to soil-borne microbes during lactation was related with modulation of gut microbiota and immune function. To identify the potential molecular mechanisms and pathways impacted by early-life topsoil exposure, we analyzed the messenger RNA (mRNA) and micro-RNA (miRNA) expression in peripheral blood mononuclear cells (PBMCs) from these piglets. Total RNA was extracted from the PBMCs of piglets exposed to topsoil only from d 4–d 21 of life (mRNA n = 6; miRNA n = 5) or unexposed control pigs (mRNA n = 6; miRNA n = 8) at 11, 20, and 56 days of age. Small RNA and mRNA were sequenced with 50-bp single-end reads using Illumina chemistry. Sequence data were quality checked with FASTQC software and aligned to the Sscrofa 11.1 genome with the STAR aligner for mRNA and mirDeep2 for miRNA. Differential expression (DE) analysis was performed using PROC Glimmix of SAS to evaluate changes in expression due to topsoil exposure over time with genes declared DE at a false discovery rate (FDR) of q &lt; 0.10. A total of 138 mRNA and 21 miRNAs were identified as DE for the treatment by age interaction. Ontology enrichment analysis of DE mRNA revealed Gene ontology (GO) terms directly involved in the connection between T-cell and antigen-presenting cells that are associated with T-cell activation. Key regulatory genes identified include PTPRJ, ITGB3, TRBV30, CD3D, mir-143, mir-29, and mir-148a. While these results require validation, this study provides data supporting the hypothesis that less-hygienic environments during early life may contribute to the development of the immune system.

Microbial Dysbiosis Tunes the Immune Response Towards Allergic Disease Outcomes

The hygiene hypothesis has been popularized as an explanation for the rapid increase in allergic disease observed over the past 50 years. Subsequent epidemiological studies have described the protective effects that in utero and early life exposures to an environment high in microbial diversity have in conferring protective benefits against the development of allergic diseases. The rapid advancement in next generation sequencing technology has allowed for analysis of the diverse nature of microbial communities present in the barrier organs and a determination of their role in the induction of allergic disease. Here, we discuss the recent literature describing how colonization of barrier organs during early life by the microbiota influences the development of the adaptive immune system. In parallel, mechanistic studies have delivered insight into the pathogenesis of disease, by demonstrating the comparative effects of protective T regulatory (Treg) cells, with inflammatory T helper 2 (Th2) cells in the development of immune tolerance or induction of an allergic response. More recently, a significant advancement in our understanding into how interactions between the adaptive immune system and microbially derived factors play a central role in the development of allergic disease has emerged. Providing a deeper understanding of the symbiotic relationship between our microbiome and immune system, which explains key observations made by the hygiene hypothesis. By studying how perturbations that drive dysbiosis of the microbiome can cause allergic disease, we stand to benefit by delineating the protective versus pathogenic aspects of human interactions with our microbial companions, allowing us to better harness the use of microbial agents in the design of novel prophylactic and therapeutic strategies.

Age-specific associations of early daycare, older siblings, severe airway infection, and preterm birth with subsequent atopic diseases

BACKGROUND

The effects of infection and developmental adaptations in infancy on the prevalence of subsequent atopy-related diseases at different ages during childhood are not fully determined. This study aims to examine the similarities and differences in the age-specific association of asthma, allergic rhinitis/conjunctivitis, and atopic dermatitis with early-life infection-related factors (i.e., daycare, older siblings, and severe airway infection) and developmental adaptations (i.e., preterm birth and rapid weight gain) in children.

METHODS

In this longitudinal cohort study (n = 47,015), children were followed from 0.5 to 11 years. The potential risks and protective factors, including daycare attendance at 0.5 years, existence of older siblings, history of hospitalization due to cold/bronchitis/bronchiolitis/pneumonia during 0.5-1.5 years, preterm birth, and rapid weight gain in the first 2.5 years, were assessed using multivariable logistic regression with adjustments for potential confounders.

RESULTS

A protective association was observed between early-life daycare attendance and asthma at 5.5-9 years, which disappeared after 10 years. A protective association was also noted throughout childhood between early daycare attendance and older siblings with allergic rhinitis/conjunctivitis. However, the association between early daycare and atopic dermatitis was found to be risky during childhood. In contrast, the early-life history of hospitalization owing to cold/bronchitis/bronchiolitis/pneumonia was identified to be a risk factor for developing both asthma and allergic rhinitis/conjunctivitis. Preterm birth was a significant risk factor for childhood asthma.

CONCLUSION

Different age-specific patterns were demonstrated in the relationship between early daycare, severe airway infection, preterm birth, and atopy-related diseases in childhood.

Antibiotic exposure and adverse long-term health outcomes in children: a systematic review and meta-analysis

BACKGROUND

Antibiotics are among the most commonly used drugs in children. In addition to inducing antibiotic resistance, antibiotic exposure has been associated with long-term adverse health outcomes.

METHODS

A systematic search using PRISMA Guidelines to identify original studies reporting associations between antibiotic exposure and long-term adverse health outcomes in children. Overall pooled estimates of the odds ratios (ORs) were obtained using fixed or random-effects models.

RESULTS

We identified 160 observational studies investigating 21 outcomes in 22,103,129 children. Antibiotic exposure was associated with an increased risk of atopic dermatitis (OR 1.40, 95% confidence interval (CI) 1.30-1.52, p<0.01), allergic symptoms (OR 1.93, 95%CI 1.66-2.26, p<0.01), food allergies (OR 1.35, 95%CI 1.20-1.52, p<0.01), allergic rhinoconjunctivitis (OR 1.66, 95%CI 1.51-1.83, p<0.01), wheezing (OR 1.81, 95%CI 1.65-1.97, p<0.01), asthma (OR 1.96, 95%CI 1.76-2.17, p<0.01), increased weight gain or overweight (OR 1.18, 95%CI 1.11-1.26, p<0.01), obesity (OR 1.21, 95%CI 1.05-1.40, p<0.01), juvenile idiopathic arthritis (OR 1.74, 95%CI 1.21-2.52, p<0.01), psoriasis (OR 1.75, 95%CI 1.44-2.11, p<0.01), autism spectrum disorders (OR 1.19, 95%CI 1.04-1.36, p=0.01) and neurodevelopment disorders (OR 1.29, 95%CI 1.09-1.53, p<0.01). Dose-response effects and stronger effects with broad-spectrum antibiotic were often reported. Antibiotic exposure was not associated with an altered risk of allergic sensitisation, infantile colic, abdominal pain, inflammatory bowel disease, celiac disease, type 1 diabetes, fluorosis, and attention deficit hyperactivity disorder.

CONCLUSION

Although a causal association cannot be determined from these studies, the results support the meticulous application of sound antibiotic stewardship to avoid potential adverse long-term health outcomes.

Association between early childhood lower respiratory tract infections and subsequent asthma

OBJECTIVE

We examined the relationship between recurrent lower respiratory tract infections (LRTI) in young children and subsequent childhood asthma outcomes.

METHODS

Retrospective cohort study using 2009-2017 Colorado All Payer Claims Database to assess 0- to 2-year-old children with visits due to LRTI and acute gastroenteritis (AGE). The primary exposure was number of LRTI visits prior to 2 years of age. Children with AGE served as the no LRTI comparator group. The primary outcome was incident asthma, defined by ICD-9 (490.XX) or ICD-10 (J45.9XX) codes, in the same children between 3 and 9 years of age. Multivariable accelerated failure time (AFT) models were used to estimate the effect of LRTI visits on median time to asthma diagnosis. Sensitivity analyses were performed using more conservative asthma diagnostic criteria and with hospitalized children only.

RESULTS

Of 38,441 eligible subjects, 32,729 had ≥1 LRTI and 5,712 had AGE (no LRTI) between 0 and 2 years of age. Children with ≥3 LRTI visits had an 80% decrease in median time to asthma diagnosis relative to those with AGE visits only (time ratio [TR] 0.2; 95% CI 0.16, 0.24). Children with ≥3 LRTI hospitalizations had a 98% reduction in median time to asthma diagnosis relative to those with AGE hospitalizations only (TR 0.02; 95% CI 0.01, 0.07). History of atopy, wheezing, and family history of asthma documented prior to 2 years of age were also associated with earlier asthma diagnosis.

CONCLUSIONS

Recurrent LRTIs, especially LRTI hospitalizations, before 2 years of age are associated with earlier diagnosis of pediatric asthma.

Does the epithelial barrier hypothesis explain the increase in allergy, autoimmunity and other chronic conditions?

There has been a steep increase in allergic and autoimmune diseases, reaching epidemic proportions and now affecting more than one billion people worldwide. These diseases are more common in industrialized countries, and their prevalence continues to rise in developing countries in parallel to urbanization and industrialization. Intact skin and mucosal barriers are crucial for the maintenance of tissue homeostasis as they protect host tissues from infections, environmental toxins, pollutants and allergens. A defective epithelial barrier has been demonstrated in allergic and autoimmune conditions such as asthma, atopic dermatitis, allergic rhinitis, chronic rhinosinusitis, eosinophilic esophagitis, coeliac disease and inflammatory bowel disease. In addition, leakiness of the gut epithelium is also implicated in systemic autoimmune and metabolic conditions such as diabetes, obesity, multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis and autoimmune hepatitis. Finally, distant inflammatory responses due to a 'leaky gut' and microbiome changes are suspected in Alzheimer disease, Parkinson disease, chronic depression and autism spectrum disorders. This article introduces an extended 'epithelial barrier hypothesis', which proposes that the increase in epithelial barrier-damaging agents linked to industrialization, urbanization and modern life underlies the rise in allergic, autoimmune and other chronic conditions. Furthermore, it discusses how the immune responses to dysbiotic microbiota that cross the damaged barrier may be involved in the development of these diseases.

The role of the pediatric cutaneous and gut microbiomes in childhood disease: A review

OBJECTIVE

Infancy and early childhood are crucial periods in the development of the human microbiome and shape the trajectory of microbial colonization, immune system development, and systemic disease. We review the development of the skin and gut microbiomes, their connection to the immune system, and their relevance to common pediatric pathologies.

FINDINGS

Beginning after birth, and likely even in utero, colonization of the skin and the gut occur in parallel, influenced by external factors. This colonization, in turn, dictates maturation of the immune system and contributes to conditions from atopic dermatitis to sepsis. Emerging literature is identifying links between the gut and skin microbiomes.

CONCLUSION

The gut and skin microbiomes are associated with pediatric disease states. Immune and microbial plasticity make this unique period an ideal target for intervention. Investigating the purposeful manipulation of the pediatric microbiome may lead to novel treatment and prevention strategies.

Effects of early-life exposure to dust mite allergen and endotoxin on the development of asthma and wheezing: The Japan Environment and Children's Study

BACKGROUND

The effects of early-life exposure to house dust mite allergen and endotoxin on the development of asthma are unclear in the literature. We investigated the association of early-life exposure (0-36 months old) to house dust mite allergen and endotoxin with asthma incidence.

METHODS

In this novel, large-scale, nationwide birth cohort study, 5017 participants were randomly selected from those who met the eligibility criteria. House dust was vacuum-sampled from the children's mattresses within homes and assayed for the presence of dust mite allergen (Der 1) and endotoxin. The participants were classified into four quartiles (Q1-Q4) according to exposure levels. We defined the incidence of asthma and wheezing using questionnaires at 12, 24, and 36 months old. Odds ratios (ORs) of the incidence of asthma and wheezing by age in Der 1 and endotoxin exposure level were estimated using logistic regression.

RESULTS

The cumulative incidence rates of asthma and wheezing during 0-36 months were 10.4% and 38.1%, respectively. Significant ORs were observed in asthma onset during 12-24 months old, asthma onset during 24-36 months old, and wheezing onset during 0-12 months old in the Q4 Der 1 group. In the Q4 endotoxin group, significant positive associations between endotoxin exposure and asthma (OR 2.00, 95% confidence interval [CI]: 1.03-3.85) and wheezing (OR 1.78, 95% CI: 1.01-3.12) onset during 24-36 months old were found.

CONCLUSIONS

Our results indicated that high levels of early-life exposure to Der 1 and endotoxin in mattresses may be involved in the development of asthma.

Association between vesicoureteral reflux, urinary tract infection and antibiotics exposure in infancy and risk of childhood asthma

Background

The use of antibiotics for treating infection in childhood and their association with increased risk of asthma remain controversial. Infants diagnosed with vesicoureteral reflux (VUR) belong to a unique population who are administered antibiotics for a long time and are susceptible to recurrent UTI. It is interesting to study the risk of asthma in these infants with or without VUR.

Methods

Taiwanese children born between 2000 and 2007 were enrolled in population-based birth cohort study. Participants diagnosed with VUR and UTI within first year were classified into four groups (VUR, UTI, VUR and UTI, and control). We calculated follow-up person-years for each participant from the index date until the asthma diagnosis, their withdrawal from the insurance system (because of death or loss to follow-up), or till the end of 2008. The risk of asthma was compared between the 4 cohorts by using Cox proportional hazards model analysis, adjusted hazard ratio (aHR), and 95% confidence interval (95% CI).

Results

Children diagnosed with VUR (n  =  350), UTI (n  =  15542), VUR and UTI (n  =  1696), and randomly selected controls (n  =  17588) were enrolled. The overall rate of incidence of asthma was found to be 1.64-fold, 1.45-fold, and 1.17-fold higher in the UTI, VUR/UTI, and VUR cohorts than in the controls (5.60, 5.07, and 4.10 vs. 3.17 per 100 person-years), respectively. After adjusting the potential factors, the overall risk of asthma remained the highest in UTI (aHR: 1.74, 95% CI : 1.65 to 1.80) followed by VUR/UTI (aHR: 1.56, 95% CI : 1.40 to 1.75) and VUR cohorts (aHR: 1.25, 95% CI: 0.96 to 1.62). The incidence of asthma was higher in boys than in girls.

Conclusion

The nationwide retrospective cohort study demonstrated that short-term therapeutic dose of antibiotics for UTI in infants with or without VUR has a positive correlation with the prevalence of childhood asthma. Significant risk of childhood asthma was not observed when VUR cohort was exposed to long-term low-dose of prophylactic antibiotics.

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).

Protection against allergies: Microbes, immunity, and the farming effect

The prevalence of asthma and other allergic diseases has rapidly increased in "Westernized" countries over recent decades. This rapid increase suggests the involvement of environmental factors, behavioral changes or lifestyle, rather than genetic drift. It has become increasingly clear that the microbiome plays a key role in educating the host immune system and, thus, regulation of disease susceptibility. This review will focus on recent advances uncovering immunological and microbial mechanisms that protect against allergies, in particular, within the context of a farming environment. A whole body of epidemiological data disclosed the nature of the protective exposures in a farm. Current evidence points toward an important role of the host microbiome in setting an immunological equilibrium that determines progression toward, or protection against allergic diseases. Conclusive mechanistic insights on how microbial exposures prevent from developing allergic diseases in humans are still lacking but findings from experimental models reveal plausible immunological mechanisms. Gathering further knowledge on these mechanisms and confirming their relevance in humans is of great importance to develop preventive strategies for children at risk of developing allergies.

The Role of Atopy in COPD and Asthma

Common to several allergic diseases is the generation of immunoglobulin E (IgE) by plasma cells, when exposed to an innocuous antigen. Asthma and chronic obstructive pulmonary disease (COPD) are two prevalent chronic airway inflammatory diseases. Asthma is mediated in some patients through eosinophilic inflammatory mechanisms that include allergic sensitization and Th2-mediated immune airway response. COPD, on the other hand is mainly considered a Th1-mediated inflammatory process with neutrophilic predominance or a non-Th2 inflammation, occasionally associated with the presence of airway bacteria or viruses. IgE production appears to play an important role in the development of both COPD and asthma, as it has been associated to respiratory symptoms, lung function, bacterial and viral infections, airway remodeling and bronchial hyperreactivity in both diseases. The aim of this review is to summarize all current data concerning the role of specific and total IgE in COPD and asthma and to highlight similarities and differences in view of possible therapeutic interventions.

Cellular and molecular mechanisms of allergic asthma

Asthma is a chronic disease of the airways, which affects more than 350 million people worldwide. It is the most common chronic disease in children, affecting at least 30 million children and young adults in Europe. Asthma is a complex, partially heritable disease with a marked heterogeneity. Its development is influenced both by genetic and environmental factors. The most common, as well as the most well characterized subtype of asthma is allergic eosinophilic asthma, which is characterized by a type 2 airway inflammation. The prevalence of asthma has substantially increased in industrialized countries during the last 60 years. The mechanisms underpinning this phenomenon are incompletely understood, however increased exposure to various environmental pollutants probably plays a role. Disease inception is thought to be enabled by a disadvantageous shift in the balance between protective and harmful lifestyle and environmental factors, including exposure to protective commensal microbes versus infection with pathogens, collectively leading to airway epithelial cell damage and disrupted barrier integrity. Epithelial cell-derived cytokines are one of the main drivers of the type 2 immune response against innocuous allergens, ultimately leading to infiltration of lung tissue with type 2 T helper (T_H2) cells, type 2 innate lymphoid cells (ILC2s), M2 macrophages and eosinophils. This review outlines the mechanisms responsible for the orchestration of type 2 inflammation and summarizes the novel findings, including but not limited to dysregulated epithelial barrier integrity, alarmin release and innate lymphoid cell stimulation.

The intersect of genetics, environment, and microbiota in asthma-perspectives and challenges

In asthma, a significant portion of the interaction between genetics and environment occurs through microbiota. The proposed mechanisms behind this interaction are complex and at times contradictory. This review covers recent developments in our understanding of this interaction: the "microbial hypothesis" and the "farm effect"; the role of endotoxin and genetic variation in pattern recognition systems; the interaction with allergen exposure; the additional involvement of host gut and airway microbiota; the role of viral respiratory infections in interaction with the 17q21 and CDHR3 genetic loci; and the importance of in utero and early-life timing of exposures. We propose a unified framework for understanding how all these phenomena interact to drive asthma pathogenesis. Finally, we point out some future challenges for continued research in this field, in particular the need for multiomic integration, as well as the potential utility of asthma endotyping.

Effects of indoor environment and lifestyle on respiratory health of children in Chongqing, China

Background

The prevalence of certain respiratory diseases of children in China appears to be on the rise in recent decades. This study aims to explore residential environmental factors that may affect respiratory diseases and lung function of children and to assess the effects of lifestyle (diet and exercise) on lung function.

Methods

The study was conducted in Chongqing, southwest of China in June, 2017. Information on respiratory diseases was obtained from 2,126 primary school children through a family questionnaire by purposive sampling. In addition, a random sample of 771 children participating in the family-questionnaire was selected for physical measurements and lung function test as well as lifestyle questionnaire survey. Chi-square test and multivariate logistic regressions were used to analyze the relationship between indoor environment and children's respiratory diseases. The effects of indoor environment and lifestyle on lung function indices were analyzed by t-test, variance analysis, and univariate and multivariate linear regression methods.

Results

Among residential environmental factors, indoor ventilation and air circulation were significant associated with children's respiratory health outcomes. The use of air conditioning for more than 8 h/day in summer was a risk factor for asthma with an adjusted odds ratio (AOR) of 1.99, bronchitis (AOR =1.62), and allergic rhinitis (AOR =1.51). Ventilation for less than 12 h per day during summer increased the risk for allergic rhinitis (AOR =1.40). Children living in homes with an opened kitchen had the risk of developing allergic rhinitis 1.51 times higher than children living in homes with a closed kitchen. Indoor dampness and mold were significantly associated with increased risks for childhood asthma (AOR =2.16), bronchitis (AOR =1.55) and allergic rhinitis (AOR =1.55). The frequent use of hygienic incense and mosquito coils also increased the risk for asthma (AOR =2.58) and bronchitis (AOR =1.42) in children. The multiple linear regression results showed that frequent use of air fresheners reduced children's peak expiratory flow (PEF) and small airway function (FEF_25-75) after potential influencing factors were adjusted for. Analyses of lifestyle variables showed that increased lung function (FVC, FEV₁, FEV₃) was associated with increasing consumption of vegetable and fruit as well as increasing time of physical exercise.

Conclusions

This study identified the following residential risk factors for children's respiratory diseases in Chongqing: poor indoor ventilation, home dampness and mold presence, and frequent use of hygienic incense and mosquito coils. Frequent use of air fresheners is associated with reduced lung function in children. High frequency consumption of vegetables, fruits and dairy products as well as daily exercise for more than 1 hour have positive effects on children's lung development.

Immunomodulatory effect of different extracts from Angiostrongylus cantonensis on airway inflammation in an allergic asthma model

This study aimed to evaluate the effects of early-life exposure to different extracts of Angiostrongylus cantonensis (A. cantonensis) on airway inflammation in an allergic asthma model. The total soluble extract (TE) and the soluble extracts of the digestive (AcD), reproductive (AcR), and cuticle (AcC) systems of A. cantonensis were used for immunisation before ovalbumin (OVA)-sensitisation/challenge in an OVA-induced allergic asthma model. The initial hypothesis of the study was that some soluble extract of the systems (AcD, AcR, or AcC) could be more potent to the modulation of inflammation than the TE. Our data, however, shows that immunisation with the TE is more promising because it decreased the high influx of inflammatory cells on airways and promoted an increase of interferon-γ (IFN-ɣ) and interleukin-10 (IL-10) levels. Besides this, the immunisation with the TE also led to a reduction of goblet cells and mucus overproduction in the lung tissue of asthmatic mice. We believe that the extracts have a distinct capacity to modulate the immune system, due to the TE possessing a greater variability of molecules, which together leads to control of airway inflammation. In conclusion, this is the first study to reveal that the TE of A. cantonensis adult worms has a greater potential for developing a novel therapeutic for allergic asthma.

Asthma increases the risk of herpes zoster: a nested case-control study using a national sample cohort

Background

This study aimed to complement previous studies on the risk of herpes zoster in the asthmatic adult population.

Methods

The Korean Health Insurance Review and Assessment Service—National Sample Cohort (HIRA-NSC) from 2002 through 2013 was used. A total of 64,152 participants with herpes zoster were matched for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia with 239,780 participants who were included as a control group. In both the herpes zoster and control groups, previous history of asthma were investigated. The crude and adjusted odds ratios (ORs) and 95% confidence intervals (CI) of asthma for herpes zoster were analyzed using unconditional logistic regression analysis. Subgroup analyses were conducted according to age and sex.

Results

Approximately 16.2% (9728/59,945) and 12.8% (30,752/239,780) of participants in the herpes zoster and control groups, respectively, had a previous history of asthma (P < 0.001). The herpes zoster group demonstrated a 1.32-times higher odds of asthma than the control group (95% CI 1.28–1.35, P < 0.001). The increased odds of asthma in the herpes zoster group persisted in all the age and sex subgroups.

Conclusions

The odds for asthma were higher in the herpes zoster group.

Role of Environmental Adjuvants in Asthma Development

PURPOSE OF REVIEW

This review summarizes recent progress in our understanding how environmental adjuvants promote the development of asthma.

RECENT FINDINGS

Asthma is a heterogeneous set of lung pathologies with overlapping features. Human studies and animal models suggest that exposure to different environmental adjuvants activate distinct immune pathways, which in turn give rise to distinct forms, or endotypes, of allergic asthma. Depending on their concentrations, inhaled TLR ligands can activate either type 2 inflammation, or Th17 differentiation, along with regulatory responses that function to attenuate inflammation. By contrast, a different category of environmental adjuvants, proteases, activate distinct immune pathways and prime predominantly type 2 immune responses. Asthma is not a single disease, but rather a group of pathologies with overlapping features. Different endotypes of asthma likely arise from perturbations of distinct immunologic pathways during allergic sensitization.

The impact of bacteria-derived ultrafine dust particles on pulmonary diseases

The relationship between ambient particulate matter exposure and health has been well established. Ultrafine particles (UFP) with a diameter of 100 nm or less are known to increase pulmonary disease risk. Biological factors in dust containing UFP can cause severe inflammatory reactions. Pulmonary diseases develop primarily as a result of chronic inflammation caused by immune dysfunction. Thus, this review focuses on the adverse pulmonary effects of biological UFP, principally lipopolysaccharide (LPS), and bacterial extracellular vesicles (EVs), in indoor dust and the pathophysiological mechanisms involved in the development of chronic pulmonary diseases. The impact of LPS-induced pulmonary inflammation is based primarily on the amount of inhaled LPS. When relatively low levels of LPS are inhaled, a cascade of immune responses leads to Th2 cell induction, and IL-5 and IL-13 released by Th2 cells contributes to asthma development. Conversely, exposure to high levels of LPS induces a Th17 cell response, leading to increased production of IL-17, which is associated with asthma, COPD, and lung cancer incidence. Responses to bacterial EV exposure can similarly be broadly divided based on whether one of two mechanisms, either intracellular or extracellular, is activated, which depends on the type of the parent cell. Extracellular bacteria-derived EVs can cause neutrophilic inflammation via Th17 cell induction, which is associated with asthma, emphysema, COPD, and lung cancer. On the other hand, intracellular bacteria-derived EVs lead to mononuclear inflammation via Th1 cell induction, which increases the risk of emphysema. In conclusion, future measures should focus on the overall reduction of LPS sources in addition to the improvement of the balance of inhaled bacterial EVs in the indoor environment to minimize pulmonary disease risk.

OM-85 BV for primary prevention of recurrent airway infections: a pilot randomized, double-blind, placebo-controlled study

Objective

To compare the frequency of respiratory tract infections in children treated with OM-85 BV and placebo during the 3-month therapy period, and observation for a further 3 months after treatment.

Methods

A randomized, double-blind, placebo-controlled trial was conducted with 54 children (6 months to 5 years old) with no past history of recurrent respiratory infections attending daycare center. Family members were instructed to administer one capsule per day for 10 consecutive days, for 3 months of OM-85 BV or placebo. Telephone interviews were conducted every 30 days.

Results

There was no significant difference in the number of respiratory infections between the groups. The mean number of respiratory tract infection in the OM-85 BV Group in the first 3 months was 0.92±0.87, and in the Placebo Group was 0.74±1.02, and at 6 months it was 1.62±1.47 and 1.03±1.34, respectively.

Conclusion

OM-85 BV was not effective in the primary prevention of respiratory tract infections. Although most authors recommend the use of this immunostimulant in children with a history of recurrent respiratory infections, more studies are needed to define its usefulness in the primary prevention of respiratory infections in healthy children exposed to few risk factors.

Respiratory viral infection in early life and development of asthma in childhood: A protocol for systematic review and meta-analysis

BACKGROUND

Respiratory viruses are the leading cause of early life wheezing that may contribute to the development of childhood asthma leading to increasing morbidity and socioeconomic burden. The aim of this review is to identify whether respiratory viral infections during first year of life were associated with development of childhood asthma.

METHODS

We will search major scientific databases (MEDLINE, CINAHL, Web of Science, Cochrane Library, and ClinicalTrials.gov) using truncated and phrase-searched keywords and relevant subject headings. Observational studies including case-control studies, cohort studies, and randomized control trails published in English will be included in this review. Case reports, qualitative studies, and narrative overviews will be excluded. Exposure will be defined as laboratory-confirmed viral respiratory tract infection in the first year of life and outcome will be defined as development of asthma between ages 5 and 18 years. Effect sizes in bivariate and multivariate analyses will be presented as odds or prevalence ratios. We will explore for heterogeneity of the standard errors across the studies, and if appropriate, we will perform a meta-analysis using a random-effects model to present a summary estimate of the odds or prevalence ratios.

RESULTS

This review will assess whether respiratory viral infections during first year of life increases the risk of childhood asthma development.

CONCLUSIONS

This systematic review will evaluate published literature, assessing the link between early life viral infection and childhood asthma. Pooled data may provide evidence that infantile respiratory viral infection results in higher incidence of recurrent wheezing and asthma, thereby stimulating further research into the cost-effectiveness of pharmaceutical interventions such as vaccines and nonpharmaceutical interventions such as hand-washing and respiratory hygiene promotion to young children. Implementing the results of such research may then reduce the burden of acute viral respiratory infections and subsequent recurrent wheezing and asthma.

SYSTEMATIC REVIEW REGISTRATION

This systematic review has been registered on PROSPERO (CRD42018105519).

Prevalence of and factors associated with adult-onset asthma in different ethnic groups: The HELIUS study

Little is known about adult-onset asthma in different ethnic groups. The aim of this study was to examine ethnic differences in the prevalence of adult-onset asthma and factors associated with this phenotype. Cross-sectional data of 23,356 participants of the HELIUS study were used, including Dutch, South-Asian Surinamese, African Surinamese, Moroccan, Turkish and Ghanaian origin participants. Adult-onset asthma was defined as: self-reported asthma symptoms or start of asthma-medication at age ≥18 years combined with a smoking history <10 pack years. The prevalence of adult-onset asthma and its association with potential risk factors were assessed by logistic regression analyses. The adjusted prevalence of adult-onset asthma was higher in the Turkish, Moroccan and South-Asian Surinamese groups (4.9-6.0%) compared to the Dutch, Ghanaian and African Surinamese origin groups (2.4-2.6%). In addition to ethnicity, age, female sex, BMI, and doctors' diagnosis of nasal allergy/hay fever and chronic sinusitis/polyps were independently associated with adult-onset asthma. There are significant differences in the adjusted prevalence of adult-onset asthma among six ethnic groups.

Is Adenoidectomy and/or Tonsillectomy a Risk Factor for Allergic Diseases and Asthma in Adulthood?

Objective

To determine the relationship between adenoidectomy and/or tonsillectomy in childhood and allergic diseases in adulthood.

Materials and Methods

A survey investigating the history of adenoidectomy and/or tonsillectomy was administered to patients that were followed-up by our department between January and June 2014 with the diagnosis of asthma, allergic rhinitis, urticaria-angioedema, drug allergy, food allergy, and venom allergy; patients willing to participate were included in the study. The relationship and risk ratios were analyzed.

Results

Totally, 510 (female/male: 379/131) patients were included in the study: 248 with asthma, 205 with rhinitis, 82 with drug allergy, 73 with urticaria, 24 with food allergy, and 14 with venom allergy. Of these, 65 (12.7%) had undergone adenoidectomy and/or tonsillectomy. Of these 65 patients, 41 had asthma, 33 had allergic rhinitis, and 28 had other allergic diseases. No relation between the history of atopy and adenoidectomy and/or tonsillectomy (p=0.129) was detected; however, there was a positive correlation between asthma and patients aged <15 years having a history of tonsillectomy and/or adenoidectomy (p=0.020). The risk of asthma was determined to be increased by 1.96 fold among the patients, provided the patient had undergone adenoidectomy and/or tonsillectomy (confidence interval [CI]:1.14-3.36). No connection was observed between atopic and non-atopic asthmatic patients in relation to adenoidectomy and/or tonsillectomy (p=0.46). No relationship was observed between allergic rhinitis and adenoidectomy and/or tonsillectomy.

Conclusion

Adenoidectomy and/or tonsillectomy in childhood increase the risk of asthma in adulthood, whereas it does not increase the risk of atopy. This result signifies the criticality of adenoidectomy or tonsillectomy in the pathogenesis of asthma.

Primary Prevention of Airway Allergy

Purpose of review

The aim of this paper is to review and summarize the current knowledge of prevention of airway allergy.

Recent findings

Allergic rhinitis and asthma are allergic airway diseases. Due to their increasing incidence and socioeconomic burden, allergic airway diseases have recently gained attention worldwide. The primary prevention of allergic airway diseases focuses on offspring’s gestational and childhood environment, such as maternal smoking and diet during pregnancy and breastfeeding as well as exposure to environmental microbes and irritants.

Summary

Asthma and allergic rhinitis are a major public health problem worldwide. They have increasing prevalence and thus attempts to their prevention are mandatory. Rapid action needs to be taken to restrain smoking among children and adolescents in order to prevent burden of allergic airway diseases. Exposure to pollution and environmental issues concerning hygiene and lifestyle would also need to be actively addressed. More evidence is still needed in order to draw linings concerning maternal diet and other factors during the offspring’s whole life span.

Developmental programming of aging trajectory

There is accumulating evidence that aging phenotype and longevity may be developmentally programmed. Main mechanisms linking developmental conditions to later-life health outcomes include persistent changes in epigenetic regulation, (re)programming of major endocrine axes such as growth hormone/insulin-like growth factor axis and hypothalamic-pituitary-adrenal axis and also early-life immune maturation. Recently, evidence has also been generated on the role of telomere biology in developmental programming of aging trajectory. In addition, persisting changes of intestinal microbiota appears to be crucially involved in these processes. In this review, experimental and epidemiological evidence on the role of early-life conditions in programming of aging phenotypes are presented and mechanisms potentially underlying these associations are discussed.

Association of childhood croup and increased incidence of airway hyperreactivity in adulthood

BACKGROUND

Some evidence suggests that childhood croup could be associated with increased incidence of adulthood bronchial reactivity, but its significance is uncertain. The aim of the present study was to evaluate the long-term outcome of early life croup.

PATIENTS AND METHODS

This case-control study was conducted in 2010-2012 in Isfahan, Iran. The case group consisted of 164 adolescents with a history of severe croup in early life and an equal number of healthy controls without any history of croup or other chronic or recurrent respiratory diseases. The two groups were compared according to pulmonary function tests and bronchial reactivity (exercise challenge test). Statistical analyses were performed using the SPSS software package, version 20 (SPSS Inc., Chicago, IL, USA). P < 0.05 was considered significant.

RESULTS

Baseline spirometric values (forced expiratory volume in 1^st s (FEV1), forced volume capacity (FVC), FEV1/FVC, and forced expiratory flow at 25%-75% (FEF25-75) were similar in case and control groups. A reduction in FEV1 and FEF25-75 after exercise challenge test was seen in 9% and 12.8% of patients, respectively, whereas this was reduced in only 4.2% and 6.1% of the controls (P = 0.034 and P = 0.021, respectively).

CONCLUSION

Our findings suggest that childhood croup might be a predisposing factor for bronchial hyperreactivity in adulthood. Longitudinal studies are necessary to confirm the clinical significance of these findings.

Longitudinal Associations Between Respiratory Infections and Asthma in Young Children

We examined temporal dependencies between repeated assessments of respiratory tract infections (RTIs) and asthma in children in the Leicester Respiratory Cohort, Leicestershire, United Kingdom. Information associated with asthma (i.e., doctor diagnosis, health care visits, wheeze frequency) and RTIs (i.e., cold duration and frequency, cough with colds, ear infections) in the previous 12 months was assessed repeatedly at ages 1, 4, and 6 years for children born between April 1996 and April 1997. We determined associations between contemporaneous and lagged measures of asthma and RTIs, using structural equation modelling. In 1,995 children, asthma was positively associated with contemporaneous infections. Asthma at age 6 years was positively associated with asthma at age 4 years (regression coefficient = 0.87; 95% confidence interval (CI): 0.76, 0.97), but not with asthma at age 1 year (regression coefficient = -0.01; 95% CI: -0.14, 0.11). We found no evidence for direct protective effect of infections at age 1 year on asthma either at age 4 (regression coefficient = -0.20; 95% CI: -0.51, 0.10) or 6 (regression coefficient = 0.24; 95% CI: -0.04, 0.52) years. Adjusting for potential confounders did not qualitatively change those relationships. Based on our findings, we suggest that asthma at age 6 years is directly influenced by asthma history and only indirectly, if at all, by earlier infection episodes. We found little support for a protective effect of preschool infections on asthma at early school age.

Antibiotics as Instigators of Microbial Dysbiosis: Implications for Asthma and Allergy

The human body and its resident microbiota form a complex ecosystem, shaped by both inherited and environmental factors. The use of antibiotics represents an extreme example of environmental pressure and can broadly disrupt the microbial landscape. The benefits that antibiotics have brought to modern medicine are unquestionable; however, their overuse comes with consequences, including the potential for secondary infections by opportunistic pathogens and the spread of antibiotic resistance. Here, we discuss the implications of microbial dysbiosis driven by antibiotics, with a focus on potential links with allergy and asthma. We review epidemiological data on humans, as well as mechanistic studies performed in animal models, and highlight gaps in current knowledge, which if addressed, could drive the design of novel therapeutic strategies and improved clinical care.

The effect of early child care attendance on childhood asthma and wheezing: A meta-analysis

OBJECTIVE

Research evidence offers mixed results regarding the relationship between early child care attendance and childhood asthma and wheezing. A meta-analysis was conducted to synthesize the current research evidence of the association between early child care attendance and the risk of childhood asthma and wheezing.

METHOD

Peer reviewed studies published from 1964-January 2017 were identified in MEDLINE, CINAL, and EMBASE using MeSH headings relevant to child care and asthma. Two investigators independently reviewed the selected articles from this search. All relevant articles that met our inclusion criteria were selected for further analysis. Data were extracted from studies that had sufficient data to analyze the odds of asthma or wheezing among children who attended child care.

RESULTS

The meta-analysis of 32 studies found that (1) early child care attendance is protective against asthma in children 3-5 years of age but not for children with asthma 6 years of age or older. (2) Early child care attendance increases the risk of wheezing among children 2 years of age or younger, but not the risk of wheezing for children over 2 years of age.

CONCLUSIONS

This meta-analysis shows that early child care attendance is not significantly associated with the risk of asthma or wheeze in children 6 years of age or older.

Association between childhood infection, serum inflammatory markers and intelligence: findings from a population-based prospective birth cohort study

A link between infection, inflammation, neurodevelopment and adult illnesses has been proposed. The objective of this study was to examine the association between infection burden during childhood - a critical period of development for the immune and nervous systems - and subsequent systemic inflammatory markers and general intelligence. In the Avon Longitudinal Study of Parents and Children, a prospective birth cohort in England, we examined the association of exposure to infections during childhood, assessed at seven follow-ups between age 1·5 and 7·5 years, with subsequent: (1) serum interleukin 6 and C-reactive protein (CRP) levels at age 9; (2) intelligence quotient (IQ) at age 8. We also examined the relationship between inflammatory markers and IQ. Very high infection burden (90+ percentile) was associated with higher CRP levels, but this relationship was explained by body mass index (adjusted odds ratio (OR) 1·19; 95% confidence interval (CI) 0·95-1·50), maternal occupation (adjusted OR 1·23; 95% CI 0·98-1·55) and atopic disorders (adjusted OR 1·24; 95% CI 0·98-1·55). Higher CRP levels were associated with lower IQ; adjusted β = -0·79 (95% CI -1·31 to -0·27); P = 0·003. There was no strong evidence for an association between infection and IQ. The findings indicate that childhood infections do not have an independent, lasting effect on circulating inflammatory marker levels subsequently in childhood; however, elevated inflammatory markers may be harmful for intellectual development/function.

Malnutrition among vaccinated children aged 0-5 years in Batouri, Republic of Cameroon

Objectives

Malnutrition continues to contribute to a high infant mortality rate. This study aimed to determine the prevalence of malnutrition and its potential association with the time at which complementary feeding was introduced among children aged 0-5 years in Batouri, Republic of Cameroon.

Methods

Mothers (n=212) were interviewed using a structured questionnaire. Child height or length, and weight measurements were determined and the appropriate Z-scores calculated. Multiple regression analysis was performed with the values of all nutritional status indicators as dependent variables and the time of commencing complementary feeding, and the child's age and sex, as independent variables.

Results

The prevalence of stunting (height/length for age<-2 standard deviation [SD]), underweight (weight for age<-2SD), and wasting (weight for height/length<-2SD) was 45.8%, 30.2%, and 11.3%, respectively. Even taking into consideration the biological variables, there was a significant association in the effects of time of starting complementary foods on the nutritional status indicators. Furthermore, adding socio-economic variables did not produce a rise in adjusted R2 values for all age group models concerned.

Conclusions

Approximately 30% of the children in the study region were underweight, and approximately half of the children exhibited stunting, indicating chronic malnutrition. Commencing complementary feeding at an appropriate time had a positive effect on nutritional status from approximately 2 years of age.

Influenza-derived peptides cross-react with allergens and provide asthma protection

BACKGROUND

The hygiene hypothesis is the leading concept to explain the current asthma epidemic, which is built on the observation that a lack of bacterial contact early in life induces allergic T_H2 immune responses.

OBJECTIVE

Because little is known about the contribution of respiratory tract viruses in this context, we evaluated the effect of prior influenza infection on the development of allergic asthma.

METHODS

Mice were infected with influenza and, once recovered, subjected to an ovalbumin- or house dust mite-induced experimental asthma protocol. Influenza-polarized effector memory T (Tem) cells were transferred adoptively to allergen-sensitized animals before allergen challenge. A comprehensive in silico analysis assessed homologies between virus- and allergen-derived proteins. Influenza-polarized Tem cells were stimulated ex vivo with candidate peptides. Mice were immunized with a pool of virus-derived T-cell epitopes.

RESULTS

In 2 murine models we found a long-lasting preventive effect against experimental asthma features. Protection could be attributed about equally to CD4⁺ and CD8⁺ Tem cells from influenza-infected mice. An in silico bioinformatic analysis identified 4 influenza- and 3 allergen-derived MHC class I and MHC class II candidate T-cell epitopes with potential antigen-specific cross-reactivity between influenza and allergens. Lymphocytes from influenza-infected mice produced IFN-γ and IL-2 but not IL-5 on stimulation with the aforementioned peptides. Immunization with a mixture of the influenza peptides conferred asthma protection, and peptide-immunized mice transferred protection through CD4⁺ and CD8⁺ Tem cells.

CONCLUSION

For the first time, our results illustrate heterologous immunity of virus-infected animals toward allergens. This finding extends the original hygiene hypothesis.

A population-based prospective cohort study examining the influence of early-life respiratory tract infections on school-age lung function and asthma

BACKGROUND

Early-life respiratory tract infections could affect airway obstruction and increase asthma risk in later life. However, results from previous studies are inconsistent.

OBJECTIVE

We examined the associations of early-life respiratory tract infections with lung function and asthma in school-aged children.

METHODS

This study among 5197 children born between April 2002 and January 2006 was embedded in a population-based prospective cohort study. Information on physician-attended upper and lower respiratory tract infections until age 6 years (categorised into ≤ 3 and >3-6 years) was obtained by annual questionnaires. Spirometry measures and physician-diagnosed asthma were assessed at age 10 years.

RESULTS

Upper respiratory tract infections were not associated with adverse respiratory outcomes. Compared with children without lower respiratory tract infections ≤3 years, children with lower respiratory tract infections ≤3 years had a lower FEV₁, FVC, FEV₁:FVC and forced expiratory flow at 75% of FVC (FEF₇₅) (Z-score (95% CI): ranging from -0.22 (-0.31 to -0.12) to -0.12 (-0.21 to -0.03)) and an increased risk of asthma (OR (95% CI): 1.79 (1.19 to 2.59)). Children with lower respiratory tract infections >3-6 years had an increased risk of asthma (3.53 (2.37 to 5.17)) only. Results were not mediated by antibiotic or paracetamol use and not modified by inhalant allergic sensitisation. Cross-lagged modelling showed that results were not bidirectional and independent of preschool wheezing patterns.

CONCLUSION

Early-life lower respiratory tract infections ≤3 years are most consistently associated with lower lung function and increased risk of asthma in school-aged children.

A population-based prospective cohort study examining the influence of early-life respiratory tract infections on school-age lung function and asthma

BACKGROUND

Early-life respiratory tract infections could affect airway obstruction and increase asthma risk in later life. However, results from previous studies are inconsistent.

OBJECTIVE

We examined the associations of early-life respiratory tract infections with lung function and asthma in school-aged children.

METHODS

This study among 5197 children born between April 2002 and January 2006 was embedded in a population-based prospective cohort study. Information on physician-attended upper and lower respiratory tract infections until age 6 years (categorised into ≤ 3 and >3-6 years) was obtained by annual questionnaires. Spirometry measures and physician-diagnosed asthma were assessed at age 10 years.

RESULTS

Upper respiratory tract infections were not associated with adverse respiratory outcomes. Compared with children without lower respiratory tract infections ≤3 years, children with lower respiratory tract infections ≤3 years had a lower FEV₁, FVC, FEV₁:FVC and forced expiratory flow at 75% of FVC (FEF₇₅) (Z-score (95% CI): ranging from -0.22 (-0.31 to -0.12) to -0.12 (-0.21 to -0.03)) and an increased risk of asthma (OR (95% CI): 1.79 (1.19 to 2.59)). Children with lower respiratory tract infections >3-6 years had an increased risk of asthma (3.53 (2.37 to 5.17)) only. Results were not mediated by antibiotic or paracetamol use and not modified by inhalant allergic sensitisation. Cross-lagged modelling showed that results were not bidirectional and independent of preschool wheezing patterns.

CONCLUSION

Early-life lower respiratory tract infections ≤3 years are most consistently associated with lower lung function and increased risk of asthma in school-aged children.

The Interactive Roles of Lipopolysaccharides and dsRNA/Viruses on Respiratory Epithelial Cells and Dendritic Cells in Allergic Respiratory Disorders: The Hygiene Hypothesis

The original hygiene hypothesis declares "more infections in early childhood protect against later atopy". According to the hygiene hypothesis, the increased incidence of allergic disorders in developed countries is explained by the decrease of infections. Epithelial cells and dendritic cells play key roles in bridging the innate and adaptive immune systems. Among the various pattern-recognition receptor systems of epithelial cells and dendritic cells, including toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) and others, TLRs are the key systems of immune response regulation. In humans, TLRs consist of TLR1 to TLR10. They regulate cellular responses through engagement with TLR ligands, e.g., lipopolysaccharides (LPS) acts through TLR4 and dsRNA acts through TLR3, but there are certain common components between these two TLR pathways. dsRNA activates epithelial cells and dendritic cells in different directions, resulting in allergy-related Th2-skewing tendency in epithelial cells, and Th1-skewing tendency in dendritic cells. The Th2-skewing effect by stimulation of dsRNA on epithelial cells could be suppressed by the presence of LPS above some threshold. When LPS level decreases, the Th2-skewing effect increases. It may be via these interrelated networks and related factors that LPS modifies the allergic responses and provides a plausible mechanism of the hygiene hypothesis. Several hygiene hypothesis-related phenomena, seemingly conflicting, are also discussed in this review, along with their proposed mechanisms.

The immunology of the allergy epidemic and the hygiene hypothesis

The immunology of the hygiene hypothesis of allergy is complex and involves the loss of cellular and humoral immunoregulatory pathways as a result of the adoption of a Western lifestyle and the disappearance of chronic infectious diseases. The influence of diet and reduced microbiome diversity now forms the foundation of scientific thinking on how the allergy epidemic occurred, although clear mechanistic insights into the process in humans are still lacking. Here we propose that barrier epithelial cells are heavily influenced by environmental factors and by microbiome-derived danger signals and metabolites, and thus act as important rheostats for immunoregulation, particularly during early postnatal development. Preventive strategies based on this new knowledge could exploit the diversity of the microbial world and the way humans react to it, and possibly restore old symbiotic relationships that have been lost in recent times, without causing disease or requiring a return to an unhygienic life style.

Prevalence and risk factors for wheezing and allergic diseases in preschool children: A perspective from the Mediterranean coast of Turkey

OBJECTIVES

The aim of the present study was to determine the prevalence and risk factors of allergic diseases in preschool children from one of the biggest cities in the Mediterranean Region of Turkey.

METHODS

The study population included 396 preschool children attending to urban daycare centres in Mersin. In the first stage, a comprehensive standardised questionnaire modified from the International Study of Asthma and Allergies in Childhood (ISAAC) was employed. In the second stage, serum food and inhalant specific IgE, and skin tests were performed in 45 children with frequent wheezing and 28 children with no wheezing.

RESULTS

The prevalence of ever wheezing, current wheezing, physician-diagnosed asthma, allergic rhinitis and eczema were 53% (210), 33.3% (132), 27.3% (108), 13.4% (53) and 8.3% (33), respectively. A family history of atopy (OR=2.5, 95% CI: 1.3-4.7, p=0.004), dampness at home (OR=2.4, 95% CI: 1.2-4.8, p=0.008), a history of intestinal parasites (OR=4.3, 95% CI: 1.7-10.9, p=0.002), previous history of pneumonia (OR=6.9, 95% CI: 1.9-25.9, p=0.004), initiation of complementary foods before the age of three months (OR=6.1, 95%CI: 1.4-26.9, p=0.02) and presence of food allergy (OR=3.1, 95% CI: 1.1-9.2, p=0.03) were found to be significant risk factors for physician-diagnosed asthma. The risk factors for frequent wheezing were maternal smoking during pregnancy (OR=5.2, 95% CI: 0.9-28.7, p=0.05) and high serum IgE levels (OR=2.9, 95% CI: 0.9-9.0, p=0.05) at borderline significance.

CONCLUSION

Our study was the first epidemiological study in preschool children in the Mediterranean region of Turkey and demonstrated a high prevalence of asthma and allergic diseases, probably related to humid climatic properties in addition to other environmental and genetic factors.

Regulatory T cells in allergic diseases

The pathogenesis of allergic diseases entails an ineffective tolerogenic immune response to allergens. Regulatory T (Treg) cells play a key role in sustaining immune tolerance to allergens, yet mechanisms by which Treg cells fail to maintain tolerance in patients with allergic diseases are not well understood. We review current concepts and established mechanisms regarding how Treg cells regulate different components of allergen-triggered immune responses to promote and maintain tolerance. We will also discuss more recent advances that emphasize the "dual" functionality of Treg cells in patients with allergic diseases: how Treg cells are essential in promoting tolerance to allergens but also how a proallergic inflammatory environment can skew Treg cells toward a pathogenic phenotype that aggravates and perpetuates disease. These advances highlight opportunities for novel therapeutic strategies that aim to re-establish tolerance in patients with chronic allergic diseases by promoting Treg cell stability and function.

Allergen Avoidance in Allergic Asthma

Allergic asthma is the most frequent disease among the chronic respiratory disorders in pediatric age with an important social impact. In the last years, many efforts have been made to identify effective preventive approaches to get a better control of symptoms and to obtain the best future outcomes for the patients. In patients with allergic asthma triggered by the exposure to indoor allergens, the avoidance is the first intervention to prevent the appearance or the worsening of bronchial symptoms. This review article summarized the most recent evidence from literature about the efficacy of specific control interventions for the most important allergens. Even if a wide spectrum of interventions has been suggested and may help to reduce exposure to trigger allergy for sensitized patients suffering from respiratory allergy, evidence supporting the efficacy of these approaches is still weak and subject of controversy. However, the exposure control to specific airborne allergens is still widely recommended and may be effective as part of a holistic approach to reduce the severity of allergic respiratory symptoms in sensitized individuals.

Increased seroprevalence of Enterovirus 71 IgE antibodies in asthmatic compared with non-asthmatic children

BACKGROUND

Asthma is a common pediatric chronic inflammatory airway disease. Respiratory viral infections are frequent infectious triggers for exacerbations of asthma.

OBJECTIVE

We sought to determine whether Enterovirus 71 (EV71), a ubiquitous virus that causes systemic inflammatory responses in children but is not a known respiratory pathogen, can also serve as an infectious trigger for asthma.

METHODS

Specific EV71 IgE and IgM antibodies (Abs), total serum IgE, and IL-2 and IL-4 cytokine levels in serum of asthmatic and non-asthmatic children (N = 42, ages 5-19; N = 35, ages 1-20, respectively) were measured (ELISA).

RESULTS

Asthmatic children had higher EV71 IgE Ab levels than non-asthmatic (P < 0.001). Non-asthmatic children had significantly higher EV71 IgM Ab levels than asthmatic (P < 0.001). Despite low serum IgE levels of non-asthmatic, compared with asthmatic (P < 0.001), the non-asthmatic children produced significantly more IL-2 and IL-4 than asthmatic (P < 0.001; P < 0.001). The ages of the asthmatics, but not the non-asthmatics had a significant effect on the levels of EV 71 IgE Abs (P = 0.02; P = 0.356). A test of difference between these two slopes was significant. However, the ages of the non-asthmatic, but not the asthmatic children had a significant effect on the levels of EV 71 IgM Abs; a test of difference between these two slopes was significant.

CONCLUSIONS

Increased specific EV71 IgE Ab responses may indicate that EV71 infection may also be an infectious trigger in asthma. However, the role of specific EV71 IgM Abs, Th2 cytokines, and age in non-asthmatic children should be further studied.