Familial aggregation of allergen-specific sensitization and asthma

Preterm Birth, Developmental Smoke/Nicotine Exposure, and Life-Long Pulmonary Sequelae

This review delineates the main pulmonary issues related to preterm birth, perinatal tobacco/nicotine exposure, and its effects on offspring, focusing on respiratory health and its possible transmission to subsequent generations. We review the extent of the problem of preterm birth, prematurity-related pulmonary effects, and the associated increased risk of asthma later in life. We then review the impact of developmental tobacco/nicotine exposure on offspring asthma and the significance of transgenerational pulmonary effects following perinatal tobacco/nicotine exposure, possibly via its effects on germline epigenetics.

Genetic variants of the C11orf30-LRRC32 region are associated with childhood asthma in the Chinese population

INTRODUCTION AND OBJECTIVES

To investigate whether genetic polymorphisms of C11orf30-LRRC32 region are associated with the development of childhood asthma in the Chinese population.

METHODS

A total of 732 asthma children and 824 age-matched healthy controls were included in the study. Blood samples were collected from the subjects for total IgE analysis, DNA extraction and RNA extraction. Three previously reported asthma-related SNPs were genotyped, including rs7936070 (G/T), rs7927894 (A/G), and rs6592657 (A/G). Blood samples from 50 patients and 50 controls were randomly selected to detect the mRNA expression levels of C11orf30 and LRRC32 in serum.

RESULTS

There were significantly different genotype frequencies between the two groups in terms of rs7936070 and rs7927894. Compared with controls, patients were found to have remarkably higher risk allele frequencies of rs7936070 and rs7927894. Genotype GG of rs7936070 was indicative of remarkably elevated total IgE level as compared with genotype TT and genotype GT. Similarly, genotype AA of rs7927894 was also associated with significantly elevated total IgE level. The serum expression of C11orf30 was significantly lower in the patients than in the controls. The C11orf30 expression was significantly correlated with the total IgE level (r = -0.463, p = 0.01).

CONCLUSIONS

Variants of C11orf30 were associated with the risk of childhood asthma in the Chinese population. Besides, abnormally decreased expression of C11orf30 was detected in the serum of patients, which was correlated with the total IgE level. The C11orf30 might play a role in asthma via biological pathways involving the regulation of total serum IgE level.

Association of GWAS-supported noncoding area loci rs404860, rs3117098, and rs7775228 with asthma in Chinese Zhuang population

Background

Asthma is a complicated and polygenic inheritance disease, and its prevalence increases worldwide. Recent genome‐wide association studies (GWASs) identified a significant association of single nucleotide polymorphism with asthma in the Japanese population. This study aimed to examine the association of GWAS‐supported noncoding area loci, namely rs404860, rs3117098, and rs7775228, with asthma in Chinese Zhuang population.

Methods

A case‐control study involving 223 individuals, comprising 123 patients with asthma and 100 healthy controls, was conducted. Genotypes were determined by polymerase chain reaction (PCR)/ligase detection reaction assay. The association between gene polymorphisms and asthma risk was calculated by logistic regression analysis using different genetic models through comparisons of alleles (A vs a), homozygote genotypes (AA vs aa), heterozygote genotypes (Aa vs aa), dominant models (AA+Aa vs aa), and recessive models (AA vs. Aa+aa).

Results

The distribution of the genotype frequency of rs3117098 was statistically different between the case and control groups. For rs3117098, significant associations were observed through comparisons of alleles (OR: 1.832, 95% CI: 1.048‐3.204, P = .034) and dominant models (OR: 2.065, 95% CI: 1.001‐4.260, P = .050). The statistical analysis showed no significant difference for loci rs404860 and rs7775228 between patients with asthma and controls.

Conclusion

rs3117098 may be the risk factor for asthma in Chinese Zhuang population.

Epigenetic impacts of maternal tobacco and e-vapour exposure on the offspring lung

In utero exposure to tobacco products, whether maternal or environmental, have harmful effects on first neonatal and later adult respiratory outcomes. These effects have been shown to persist across subsequent generations, regardless of the offsprings' smoking habits. Established epigenetic modifications induced by in utero exposure are postulated as the mechanism underlying the inherited poor respiratory outcomes. As e-cigarette use is on the rise, their potential to induce similar functional respiratory deficits underpinned by an alteration in the foetal epigenome needs to be explored. This review will focus on the functional and epigenetic impact of in utero exposure to maternal cigarette smoke, maternal environmental tobacco smoke, environmental tobacco smoke and e-cigarette vapour on foetal respiratory outcomes.

Is the atopic march related to confounding by genetics and early-life environment? A systematic review of sibship and twin data

A popular hypothesis known as the atopic march proposes a set of sequential allergy and respiratory disorders in early childhood contributes enormously to the burden of disease in developed countries. Although the concept of the atopic march has been refined and strengthened by many cross-sectional and longitudinal studies linking eczema as the initial manifestation with progression to hay fever and then asthma, there is yet no definitive proof that the atopic march is the primary causal factor in childhood allergic disease. This debate is mainly related to the controversy around potential confounding of these associations by genetic and environmental factors. Family studies are ideally suited to unravelling the role of these factors. While multiple reviews have synthesized evidence from studies investigating this question, no review to date has explored specific evidence generated by twin and sibling studies to understand the aetiology of atopic march diseases. Our aim was to conduct a systematic review of twin and sibling studies that examine the allergic phenotypes that form the atopic march, to determine whether such analyses of data from these studies attempt to control for the effect confounding by shared factors, and to report estimates of the magnitude of associations between multiple phenotypes. Our review suggests that (1) genetics play a bigger role predisposing eczema to hay fever and eczema to asthma than environmental factors, and (2) the link between eczema and asthma and hay fever is independent of shared early-life environmental factors.

Prevalence and factors associated with asthma in students from Montes Claros, Minas Gerais, Brazil

We investigated the prevalence of asthma and factors related to asthma development in schoolchildren aged 6 to 14, living in central and peripheral areas of the city of Montes Claros, Minas Gerais and who were registered with the Family Health Strategy program. Initially, a standard written questionnaire, based on ISAAC (International Study of Asthma and Allergies in Childhood), was administered to collect personal data, information regarding income, asthma prevalence, allergic rhinitis and eczema (N = 1,131). Secondly, a case-control study was performed by grouping the patients as either asthmatic (A; N = 172) or non-asthmatic (NA; N = 379). Potential factors associated with the occurrence of asthma were evaluated using the complementary questionnaire from ISAAC phase II. Skin tests for immediate hypersensitivity (STIH) and parasitological tests were also performed. The odds ratio, estimated by multivariate analysis, indicated that asthma cases were related to kindergarten attendance, household smoking, family history of asthma, rhinitis and positive STIH. It was concluded that, in the studied population, the prevalence of asthma was related to genetic predisposition, in addition to individual history, social demographics, exposure to pollutants such as tobacco smoke and a positive response to allergy testing.

Revisiting asthma therapeutics: focus on WNT signal transduction

Asthma is a complex disease of the airways that develops as a consequence of both genetic and environmental factors. This interaction has highlighted genes important in early life, particularly those that control lung development, such as the Wingless/Integrase-1 (WNT) signalling pathway. Although aberrant WNT signalling is involved with an array of human conditions, it has received little attention within the context of asthma. Yet it is highly relevant, driving events involved with inflammation, airway remodelling, and airway hyper-responsiveness (AHR). In this review, we revisit asthma therapeutics by examining whether WNT signalling is a valid therapeutic target for asthma.

Polymorphisms of TGFB1, TLE4 and MUC22 are associated with childhood asthma in Chinese population

OBJECTIVE

To investigate whether the genetic variants of TGFB1, TLE4, MUC22 and IKZF3 are associated with the development of asthma in Chinese children.

METHODS

572 adolescent asthma patients and 590 age-matched healthy controls were included in this study. A total of four SNPs were genotyped, including rs2241715 of TGFB1, rs2378383 of TLE4, rs2523924 of MUC22, and rs907092 of IKZF3. Allele frequencies of the patients and the control group were compared by the Chi-square test. The Student t test was used to analyse the relationship between genotypes and clinical feature of the patients.

RESULTS

Patients were found to have significantly different frequencies of allele A of rs2241715, allele G of rs2378383 and allele A of rs2523924 as compared with the controls (40.4% vs. 45.9%, p=0.01 for rs2241715; 17.2% vs. 13.4%, p=0.01 for rs2378383; 15.3% vs. 11.9%, p=0.02 for rs2523924). For patients with severe asthma, those with genotype AA/AG of rs2241715 had remarkably higher FEV1% as compared with those with genotype GG (59.1±4.3% vs. 55.4±3.7%, p<0.001). Moreover, those with genotype GG/GA of rs2378383 had remarkably lower FEV1% as compared with those with genotype AA (54.6±2.9% vs. 58.6±4.1%, p<0.001).

CONCLUSIONS

Genes TGFB1, TLE4 and MUC22 are associated with the risk of childhood asthma in Chinese population. Our results associating TGFB1 and TLE4 with clinical features of asthma suggest potential application of these parameters in the management of asthma children.

High incidence and persistence of airborne allergen sensitization up to age 19 years

BACKGROUND

Longitudinal population-based studies about the natural history of allergic sensitization are rare. The aim was to study incidence and persistence of airborne allergen sensitization up to young adulthood and risk factors for early and late onset of sensitization.

METHODS

All children aged 7-8 years in two municipalities in Northern Sweden were invited to a parental questionnaire and skin prick tests (SPTs) to ten airborne allergens, and 2148 (88%) participated. The protocol was repeated at age 11-12 and 19 years, and 1516 participated in all three examinations.

RESULTS

Prevalence of any positive SPT increased from 20.6% at age 7-8 years to 30.6% at 11-12 years, and 42.1% at 19 years. Animals were the primary sensitizers at age 7-8 years, 16.3%, followed by pollen, 12.4%. Mite and mold sensitization was low. Mean annual incidence of any positive SPT varied between 2.8 and 3.4/100 per year, decreased by age for animal, and was stable for pollen. Sensitization before age 7-8 years was independently associated with family history of allergy, OR 2.1 (95% CI 1.6-2.8), urban living, OR 1.9 (95% CI 1.2-2.9), and male sex, OR 1.3 (95% CI 1.0-1.7), and negatively associated with birth order, OR 0.8 (95% CI 0.7-1.0), and furry animals at home, OR 0.7 (95% CI 0.7-0.9). Incidence after age 11-12 years was associated only with family history of allergy. Multisensitization at age 19 years was significantly associated with early age at sensitization. Remission of sensitization was uncommon.

CONCLUSION

The increasing prevalence of allergic sensitization by age was explained by high incidence and persistence. After age 11-12 years, the factors urban living, number of siblings, and male sex lost their importance.

Allergic airway diseases in childhood: an update

Complex multifactorial diseases such as allergic rhinitis and asthma are not only becoming an increasing burden to healthcare systems, but especially affect the life quality of children and families suffering from their allergic symptoms. Also physicians are challenged by the multifaceted diseases as their work involves not only the often difficult decisions on case-adapted diagnostics, treatment, and monitoring, but also possible preventive measures. This review gives an outline of the latest scientific developments related to the etiology, diagnosis, and management of allergic airway diseases in childhood, as well as prenatal and early life risk factors and strategies for prevention.

The roles of ADAM33, ADAM28, IL-13 and IL-4 in the development of lung injuries in children with lethal non-pandemic acute infectious pneumonia

BACKGROUND

ADAM28, ADAM33, IL-13, IL-4 and other cytokines (IL-6 and IL-10) seem to play important roles in the persistence and maintenance of acute inflammatory processes that ultimately lead to lung remodeling and pulmonary fibrosis, which may be responsible for the high morbidity and mortality rates associated with non-pandemic acute viral pneumonias in childhood.

OBJECTIVES

The aim of this study was to evaluate the roles of ADAM33, ADAM28, IL4, IL6, IL10 and IL13 in the development of inflammation and alveolar fibrosis due to lethal acute respiratory infections of the lower airway in a pediatric population, especially in those with viral etiology.

STUDY DESIGN

For this study, 193 cases were selected, and samples from the cases were processed for viral antigen detection by immunohistochemistry and then separated into two groups: virus-positive (n=68) and virus-negative (n=125). Immunohistochemistry was performed to assess the presence of metalloproteinases (ADAM33 and ADAM28) and inflammatory cytokines (IL-4, IL-13, IL-6, IL-10) in the alveolar septa.

RESULTS

The virus-positive group showed stronger immunolabeling for ADAM33, ADAM28, IL-4 and IL-13 (p<0.0001 for all variables). The staining intensities for ADAM33 and ADAM28 were directly proportional to the intensities for IL-4 and IL-13 (p<0.0001).

CONCLUSIONS

The results of this study suggest that these proteins play important roles in pulmonary inflammatory reactions elicited against etiological viral agents. In addition, these mediators may affect the process of lung remodeling and the development of pulmonary fibrosis.

Identification of an interleukin 13-induced epigenetic signature in allergic airway inflammation

Epigenetic changes have been implicated in the pathogenesis of asthma. We sought to determine if IL13, a key cytokine in airway inflammation and remodeling, induced epigenetic DNA methylation and miRNAs expression changes in the airways in conjunction with its transcriptional gene regulation. Inducible expression of an IL13 transgene in the airways resulted in significant changes in DNA methylation in 177 genes, most of which were associated with the IL13 transcriptional signature in the airways. A large number of genes whose expression was induced by IL13 were found to have decreased methylation, including those involved in tissue remodeling (Olr1), leukocyte influx (Cxcl3, Cxcl5, CSFr2b), and the Th2 response (C3ar1, Chi3l4). Reciprocally, some genes whose expression was suppressed were found to have increased methylation (e.g. Itga8). In addition, miRNAs were identified with targets for lung development and Wnt signaling, amongst others. These results indicate that IL13 confers an epigenetic methylation and miRNA signature that accompanies its transcriptional program in the airways, which may play a critical role in airway inflammation and remodeling.