Genetics of asthma and allergy: what have we learned?

Long-term bidirectional association between asthma and attention deficit hyperactivity disorder: A big data cohort study

BACKGROUND

Previous studies have argued that attention deficit hyperactivity disorder (ADHD) is associated with asthma. However, reliable evidence to verify this association has not yet been reported.

OBJECTIVES

To investigate the bidirectional association between asthma and ADHD through a 12-year big data cohort study.

METHODS

The independent variable group was extracted from 3.5 million individuals randomly sampled by the National Health Insurance Service (NHIS). In Study 1, the incidence of ADHD according to asthma was evaluated, while in Study 2, the incidence of asthma according to ADHD was analyzed. Propensity score (PS) matching with several variables was used to obtain a control group.

MEASUREMENTS AND MAIN RESULTS

In Study 1, the asthma group included 131,937 individuals and the non-asthma group included 131,937 individuals. The adjusted hazard ratio (aHR) for ADHD in the asthma group was 1.17 [95% confidence interval (CI): 1.11-1.23]. In subgroup analysis, the aHRs for ADHD of individuals in the subgroups male sex, 0-5 years old, 6-10 years old, atopic dermatitis, allergic rhinitis, Charlson comorbidity index (CCI) 1, and CCI > 2 were significant (aHR: 2.83, 1.70, 1.79, 1.09, 1.15, 1.06, and 1.49, respectively). In Study 2, ADHD was found to significantly affect asthma in all age groups (aHRs of the subgroups 0∼60 and 0∼17 years old were 1.10 and 1.09, respectively). In the 0∼17 years old subgroup, the association of ADHD with asthma was greater with younger age (aHRs of the subgroups 0∼5 and 6∼10 years old were 2.53 and 1.54, respectively).

CONCLUSION

From long-term follow-up, the incidence of ADHD was 1.17 times higher in the asthma group than in the control group. The incidence of asthma was 1.10 times higher in the ADHD group than in the control group. Asthma and ADHD have a bidirectional relationship, and childhood asthma and ADHD should be rigorously managed.

Risk, Mechanisms and Implications of Asthma-Associated Infectious and Inflammatory Multimorbidities (AIMs) among Individuals With Asthma: a Systematic Review and a Case Study

Our prior work and the work of others have demonstrated that asthma increases the risk of a broad range of both respiratory (e.g., pneumonia and pertussis) and non-respiratory (e.g., zoster and appendicitis) infectious diseases as well as inflammatory diseases (e.g., celiac disease and myocardial infarction [MI]), suggesting the systemic disease nature of asthma and its impact beyond the airways. We call these conditions asthma-associated infectious and inflammatory multimorbidities (AIMs). At present, little is known about why some people with asthma are at high-risk of AIMs, and others are not, to the extent to which controlling asthma reduces the risk of AIMs and which specific therapies mitigate the risk of AIMs. These questions represent a significant knowledge gap in asthma research and unmet needs in asthma care, because there are no guidelines addressing the identification and management of AIMs. This is a systematic review on the association of asthma with the risk of AIMs and a case study to highlight that 1) AIMs are relatively under-recognized conditions, but pose major health threats to people with asthma; 2) AIMs provide insights into immunological and clinical features of asthma as a systemic inflammatory disease beyond a solely chronic airway disease; and 3) it is time to recognize AIMs as a distinctive asthma phenotype in order to advance asthma research and improve asthma care. An improved understanding of AIMs and their underlying mechanisms will bring valuable and new perspectives improving the practice, research, and public health related to asthma.

Impaired exercise capacity in electrostatic polyester powder paint workers

PURPOSE

Limited number of studies investigated the effects of Electrostatic powder paints (EPP) on human health. We investigated the effects of EPP exposure on lung function, exercise capacity, and quality of life, and the factors determining exercise capacity in EPP workers.

METHODS

Fifty-four male EPP workers and 54 age-matched healthy male individuals (control group) were included. Lung function and respiratory muscle strength were measured. The lower limit of normal (LLN) cut-points for FEV₁ and FEV₁/FVC were calculated. An EPT was used to evaluate bronchial hyperactivity. The handgrip and quadriceps muscle strength were evaluated using a hand-held dynamometer. An ISWT was used to determine exercise capacity. The physical activity level was questioned using the IPAQ. The SGRQ and NHP were used to assessing respiratory specific and general quality of life, respectively.

RESULTS

Duration of work, FEV₁, MIP, handgrip strength, and ISWT distance were significantly lower, and the change in FEV₁ after EPT and %HRmax were significantly higher in the EPP group compared to the control group (p < 0.05). There were no subjects with a < LLN for FEV₁ and FEV₁/FVC in both groups. In the EPP group, ISWT distance was significantly related to age, height, duration of work, FEV₁, change in FEV₁ after EPT, MIP, MEP, handgrip strength, IPAQ, SGRQ, and NHP total scores (p < 0.05). The change in FEV₁ after EPT, MIP, and duration of work explained % 62 of the variance in the ISWT distance (p < 0.001).

CONCLUSIONS

Changes in lung function based on LLN for the FEV₁ and FEV₁/FVC were not clinically relevant in EPP workers. Exercise capacity is impaired in EPP workers. Degree of exercise-induced bronchospasm, inspiratory muscle strength, and duration of work are the determinants of exercise capacity in EPP workers.

Gene-Environment Interaction between the IL1RN Variants and Childhood Environmental Tobacco Smoke Exposure in Asthma Risk

(1) Background: Variants of the interleukin-1 receptor antagonist (IL1RN) gene, encoding an anti-inflammatory cytokine, are associated with asthma. Asthma is a chronic inflammatory disease of the airway influenced by interactions between genetic variants and environmental factors. We discovered a gene-environment interaction (GEI) of IL1RN polymorphisms with childhood environmental tobacco smoke (ETS) exposure on asthma susceptibility in an urban adult population. (2) Methods: DNA samples from the NYU/Bellevue Asthma Registry were genotyped for tag SNPs in IL1RN in asthma cases and unrelated healthy controls. Logistic regressions were used to study the GEI between IL1RN variants and childhood ETS exposures on asthma and early onset asthma, respectively, adjusting for population admixture and other covariates. (3) Results: Whereas the rare genotypes of IL1RN SNPs (e.g., GG in SNP rs2234678) were associated with decreased risk for asthma among those without ETS exposure (odds ratio OR = 0.215, p = 0.021), they are associated with increased risk for early onset asthma among those with childhood ETS (OR = 4.467, p = 0.021). (4) Conclusions: We identified a GEI between polymorphisms of IL1RN and childhood ETS exposure in asthma. Analysis of GEI indicated that childhood ETS exposure disrupted the protective effect of some haplotypes/genotypes of IL1RN for asthma and turned them into high-risk polymorphisms for early onset asthma.

Expert artificial intelligence-based natural language processing characterises childhood asthma

INTRODUCTION

The lack of effective, consistent, reproducible and efficient asthma ascertainment methods results in inconsistent asthma cohorts and study results for clinical trials or other studies. We aimed to assess whether application of expert artificial intelligence (AI)-based natural language processing (NLP) algorithms for two existing asthma criteria to electronic health records of a paediatric population systematically identifies childhood asthma and its subgroups with distinctive characteristics.

METHODS

Using the 1997-2007 Olmsted County Birth Cohort, we applied validated NLP algorithms for Predetermined Asthma Criteria (NLP-PAC) as well as Asthma Predictive Index (NLP-API). We categorised subjects into four groups (both criteria positive (NLP-PAC⁺/NLP-API⁺); PAC positive only (NLP-PAC⁺ only); API positive only (NLP-API⁺ only); and both criteria negative (NLP-PAC^-/NLP-API^-)) and characterised them. Results were replicated in unsupervised cluster analysis for asthmatics and a random sample of 300 children using laboratory and pulmonary function tests (PFTs).

RESULTS

Of the 8196 subjects (51% male, 80% white), we identified 1614 (20%), NLP-PAC⁺/NLP-API⁺; 954 (12%), NLP-PAC⁺ only; 105 (1%), NLP-API⁺ only; and 5523 (67%), NLP-PAC^-/NLP-API^-. Asthmatic children classified as NLP-PAC⁺/NLP-API⁺ showed earlier onset asthma, more Th2-high profile, poorer lung function, higher asthma exacerbation and higher risk of asthma-associated comorbidities compared with other groups. These results were consistent with those based on unsupervised cluster analysis and lab and PFT data of a random sample of study subjects.

CONCLUSION

Expert AI-based NLP algorithms for two asthma criteria systematically identify childhood asthma with distinctive characteristics. This approach may improve precision, reproducibility, consistency and efficiency of large-scale clinical studies for asthma and enable population management.

Association of β2-adrenergic receptor gene polymorphisms (rs1042713, rs1042714, rs1042711) with asthma risk: a systematic review and updated meta-analysis

Background

The published data on the association between β2-adrenergic receptor gene polymorphisms and asthma susceptibility are inconclusive. To derive a more precise estimation of this association, a meta-analysis was performed.

Methods

A literature search was conducted in PubMed, Web of Science, EMBASE, Wanfang, and the China National Knowledge Infrastructure (CNKI) databases to identify eligible studies. The pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to calculate the strength of the association. A sensitivity analysis was performed to evaluate the influence of individual studies on the overall effect estimates, and funnel plots and Egger’s tests were used for indications of publication bias.

Results

Seventy three studies with three single nucleotide polymorphisms (SNP) (rs1042713, c.G46A, p.Gly16Arg; rs1042714, c.G79C, p.Gln27Glu; rs1042711, c.T-47C, p.Cys19Arg) were finally identified. For the rs1042713 polymorphism, no significant association with asthma risk was found in the overall population. However, a significant protective association was found in the Indian population in the dominant model comparison (OR = 0.72, 95% CI = 0.59–0.87, I² = 25%, studies = 5, cases = 1190, controls = 1241). A significant risk association was found in the Arab population in the dominant model comparison (OR = 1.75, 95% CI = 1.14–2.70, I² = 0%, studies = 2, cases = 307, controls = 361) and the homozygote model comparison (OR = 1.88, 95% CI = 1.17–3.02, I² = 0%, studies = 2, cases = 307, controls = 361), and in the Hispanic-Latino population in the dominant model comparison (OR = 1.68, 95% CI = 1.10–2.55, I² = 77%, studies = 5, cases = 1026, controls = 1412). For the rs1042714 polymorphism, we found a significant association in the recessive model comparison (OR = 0.83, 95% CI = 0.70–0.98, I² = 44%, studies = 52, cases = 8242, controls = 16,832), the homozygote genotype comparison (OR = 0.84, 95% CI = 0.72–0.98, I² = 25%, studies = 52, cases = 8242, controls = 16,832) and the allelic genetic model (OR = 0.91, 95% CI = 0.83–0.99, I² = 59%, studies = 52, cases = 8242, controls = 16,832) in the overall population. When stratified by age, a significant association was also found in children in the recessive model comparison (OR = 0.59, 95% CI = 0.39–0.88, I² = 58%, studies = 18, cases = 2498, controls = 2510) and the homozygote genotype comparison (OR = 0.63, 95% CI = 0.43–0.92, I² = 46%, studies = 18, cases = 2498, controls = 2510), but not in adult. For the rs1042711 polymorphism, no significant associations were found in the any genetic model.

Conclusion

The meta-analysis suggests that the ADRB2 rs1042714 polymorphism has a protective association with asthma in the overall population and the pediatric subgroup.

Genetic variants in 17q12-21 locus and childhood asthma in Brazil: Interaction with Varicella zoster virus seropositivity

BACKGROUND

Asthma is a complex disease with worldwide public health relevance, is related to environmental causes and a genetic predisposition. The chromosomal 17q12-21 locus has been consistently demonstrated to be associated with asthma risk. The effects of variants in the 17q12-21 locus on childhood asthma were first identified in a genome wide- association study. Since that time, those findings have been replicated in different populations but not in South American populations.

OBJECTIVE

This study aimed to investigate the role of variants in the 17q12-21 locus on asthma in a sample of Brazilian children.

METHODS

This was a cross-sectional study conducted on a cohort of 1247 children. These analyses used 50 Single Nucleotide Variants (SNVs) in the 17q12-21 locus were genotyped as part of a genome wide association study (GWAS).

RESULTS

Four SNVs (rs4065275, rs12603332, rs73985228 and rs77777702) were associated with childhood asthma. The rs73985228 exhibited the strongest association across the different genetic models (OR, 95%CI 2.8, 1.44-3.21, p < 0.01). In an analysis that was stratified by atopy, two SNVs (rs73985228 and rs2715555) were found to be associated with atopic and non-atopic asthma. For the first time, we observed a significant interaction with seropositivity for the Varicella zoster virus (for rs4065275, p = 0.02, and for rs12603332, p = 0.04); i.e., the association was found in those who were seropositive but not in those who were seronegative for this virus.

CONCLUSIONS

We confirmed the associations of variants in the 17q12-21 locus with atopic and non-atopic asthma and identified an interaction with seropositivity for the Varicella zoster virus.

Genome-wide burden and association analyses implicate copy number variations in asthma risk among children and young adults from Latin America

The genetic architecture of asthma was relatively well explored. However, some work remains in the field to improve our understanding on asthma genetics, especially in non-Caucasian populations and with regards to commonly neglected genetic variants, such as Copy Number Variations (CNVs). In the present study, we investigated the contribution of CNVs on asthma risk among Latin Americans. CNVs were inferred from SNP genotyping data. Genome wide burden and association analyses were conducted to evaluate the impact of CNVs on asthma outcome. We found no significant difference in the numbers of CNVs between asthmatics and non-asthmatics. Nevertheless, we found that CNVs are larger in patients then in healthy controls and that CNVs from cases intersect significantly more genes and regulatory elements. We also found that a deletion at 6p22.1 is associated with asthma symptoms in children from Salvador (Brazil) and in young adults from Pelotas (Brazil). To support our results, we conducted an in silico functional analysis and found that this deletion spans several regulatory elements, including two promoter elements active in lung cells. In conclusion, we found robust evidence that CNVs could contribute for asthma susceptibility. These results uncover a new perspective on the influence of genetic factors modulating asthma risk.

Automated chart review utilizing natural language processing algorithm for asthma predictive index

BACKGROUND

Thus far, no algorithms have been developed to automatically extract patients who meet Asthma Predictive Index (API) criteria from the Electronic health records (EHR) yet. Our objective is to develop and validate a natural language processing (NLP) algorithm to identify patients that meet API criteria.

METHODS

This is a cross-sectional study nested in a birth cohort study in Olmsted County, MN. Asthma status ascertained by manual chart review based on API criteria served as gold standard. NLP-API was developed on a training cohort (n = 87) and validated on a test cohort (n = 427). Criterion validity was measured by sensitivity, specificity, positive predictive value and negative predictive value of the NLP algorithm against manual chart review for asthma status. Construct validity was determined by associations of asthma status defined by NLP-API with known risk factors for asthma.

RESULTS

Among the eligible 427 subjects of the test cohort, 48% were males and 74% were White. Median age was 5.3 years (interquartile range 3.6-6.8). 35 (8%) had a history of asthma by NLP-API vs. 36 (8%) by abstractor with 31 by both approaches. NLP-API predicted asthma status with sensitivity 86%, specificity 98%, positive predictive value 88%, negative predictive value 98%. Asthma status by both NLP and manual chart review were significantly associated with the known asthma risk factors, such as history of allergic rhinitis, eczema, family history of asthma, and maternal history of smoking during pregnancy (p value < 0.05). Maternal smoking [odds ratio: 4.4, 95% confidence interval 1.8-10.7] was associated with asthma status determined by NLP-API and abstractor, and the effect sizes were similar between the reviews with 4.4 vs 4.2 respectively.

CONCLUSION

NLP-API was able to ascertain asthma status in children mining from EHR and has a potential to enhance asthma care and research through population management and large-scale studies when identifying children who meet API criteria.

Transcriptional regulation on the gene expression signature in combined allergic rhinitis and asthma syndrome

AIM

This study was intended to evaluate transcriptional regulation of gene expression signatures in combined allergic rhinitis and asthma syndrome (CARAS).

MATERIALS & METHODS

The blood samples of three patients with CARAS, three patients with allergic rhinitis and three normal controls were obtained. The cuffdiff, miRDeep2 and DEGseq were used to quantify the expression of genes and miRNAs, respectively. And p-value < 0.01 and false discovery rate < 0.001 were considered as significant differences of genes and miRNAs, respectively. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes were used to analyze the biological function. And the cut-off value for significance was p < 0.05.

RESULTS

SLC14A1, SNCA, TNS1, KAT2B and PARP1 were regulated by hsa-miR-93-5p, hsa-miR-92a-3p and hsa-miR-21-5p. Additionally, phagosome (p = 0.00627769839083361) was the only significantly enriched signal pathway involving HLA-DOA, TUBB2A and MRC2.

CONCLUSION

Disordered expression of genes under the regulation of miRNAs may play an important role in CARAS.

Natural Language Processing for Asthma Ascertainment in Different Practice Settings

BACKGROUND

We developed and validated NLP-PAC, a natural language processing (NLP) algorithm based on predetermined asthma criteria (PAC) for asthma ascertainment using electronic health records at Mayo Clinic.

OBJECTIVE

To adapt NLP-PAC in a different health care setting, Sanford Children Hospital, by assessing its external validity.

METHODS

The study was designed as a retrospective cohort study that used a random sample of 2011-2012 Sanford Birth cohort (n = 595). Manual chart review was performed on the cohort for asthma ascertainment on the basis of the PAC. We then used half of the cohort as a training cohort (n = 298) and the other half as a blind test cohort to evaluate the adapted NLP-PAC algorithm. Association of known asthma-related risk factors with the Sanford-NLP algorithm-driven asthma ascertainment was tested.

RESULTS

Among the eligible test cohort (n = 297), 160 (53%) were males, 268 (90%) white, and the median age was 2.3 years (range, 1.5-3.1 years). NLP-PAC, after adaptation, and the human abstractor identified 74 (25%) and 72 (24%) subjects, respectively, with 66 subjects identified by both approaches. Sensitivity, specificity, positive predictive value, and negative predictive value for the NLP algorithm in predicting asthma status were 92%, 96%, 89%, and 97%, respectively. The known risk factors for asthma identified by NLP (eg, smoking history) were similar to the ones identified by manual chart review.

CONCLUSIONS

Successful implementation of NLP-PAC for asthma ascertainment in 2 different practice settings demonstrates the feasibility of automated asthma ascertainment leveraging electronic health record data with a potential to enable large-scale, multisite asthma studies to improve asthma care and research.

Application of a Natural Language Processing Algorithm to Asthma Ascertainment. An Automated Chart Review

RATIONALE

Difficulty of asthma ascertainment and its associated methodologic heterogeneity have created significant barriers to asthma care and research.

OBJECTIVES

We evaluated the validity of an existing natural language processing (NLP) algorithm for asthma criteria to enable an automated chart review using electronic medical records (EMRs).

METHODS

The study was designed as a retrospective birth cohort study using a random sample of 500 subjects from the 1997-2007 Mayo Birth Cohort who were born at Mayo Clinic and enrolled in primary pediatric care at Mayo Clinic Rochester. Performance of NLP-based asthma ascertainment using predetermined asthma criteria was assessed by determining both criterion validity (chart review of EMRs by abstractor as a gold standard) and construct validity (association with known risk factors for asthma, such as allergic rhinitis).

MEASUREMENTS AND MAIN RESULTS

After excluding three subjects whose respiratory symptoms could be attributed to other conditions (e.g., tracheomalacia), among the remaining eligible 497 subjects, 51% were male, 77% white persons, and the median age at last follow-up date was 11.5 years. The asthma prevalence was 31% in the study cohort. Sensitivity, specificity, positive predictive value, and negative predictive value for NLP algorithm in predicting asthma status were 97%, 95%, 90%, and 98%, respectively. The risk factors for asthma (e.g., allergic rhinitis) that were identified either by NLP or the abstractor were the same.

CONCLUSIONS

Asthma ascertainment through NLP should be considered in the era of EMRs because it can enable large-scale clinical studies in a more time-efficient manner and improve the recognition and care of childhood asthma in practice.

Association between thromboxane A2 receptor polymorphisms and asthma risk: A meta-analysis

OBJECTIVE

To determine whether there is an association between thromboxane A2 receptor (TBXA2R) gene polymorphisms (+924C/T and +795C/T) and asthma risk by conducting a meta-analysis.

DATA SOURCES

Pubmed, Embase, Chinese National Knowledge Infrastructure (CNKI) and Wanfang database were searched (updated May 1, 2015).

STUDY SELECTIONS

Articles evaluating the association between TBXA2R gene polymorphisms and asthma risk were selected.

RESULTS

A total of 7 studies on +924C/T polymorphism and 6 studies on +795C/T polymorphism were included in this meta-analysis. There was a significant association between TBXA2R +924C/T polymorphism and asthma risk in the recessive model (OR = 1.33, 95% CI = 1.01-1.75, P = 0.045). No significant association between +795C/T polymorphism and asthma risk in the overall population was demonstrated. In subgroup analyzes, significant association was observed in atopic asthma risk in the recessive model (OR = 1.43, 95% CI = 1.01-2.01, P = 0.043), but no significant association was found between TBXA2R +924C/T polymorphism and asthma risk in Asians (OR = 1.14, 95% CI = 0.80-1.63, P = 0.457). TBXA2R +795C/T polymorphism was associated with aspirin-intolerant asthma (AIA) risk when stratified by asthma subphenotype in the allelic model (OR = 1.30, 95% CI = 1.05-1.60, P = 0.014) and dominant model (OR = 1.50, 95% CI = 1.11-2.03, P = 0.008).

CONCLUSION

Our results suggested that TBXA2R +924C/T polymorphism is associated with asthma risk, and +795C/T polymorphism may be a risk factor for AIA. Larger-scale and well-designed studies are required to validate the association identified in the current meta-analysis.

Integrated Transcriptomics Establish Macrophage Polarization Signatures and have Potential Applications for Clinical Health and Disease

Growing evidence defines macrophages (Mφ) as plastic cells with wide-ranging states of activation and expression of different markers that are time and location dependent. Distinct from the simple M1/M2 dichotomy initially proposed, extensive diversity of macrophage phenotypes have been extensively demonstrated as characteristic features of monocyte-macrophage differentiation, highlighting the difficulty of defining complex profiles by a limited number of genes. Since the description of macrophage activation is currently contentious and confusing, the generation of a simple and reliable framework to categorize major Mφ phenotypes in the context of complex clinical conditions would be extremely relevant to unravel different roles played by these cells in pathophysiological scenarios. In the current study, we integrated transcriptome data using bioinformatics tools to generate two macrophage molecular signatures. We validated our signatures in in vitro experiments and in clinical samples. More importantly, we were able to attribute prognostic and predictive values to components of our signatures. Our study provides a framework to guide the interrogation of macrophage phenotypes in the context of health and disease. The approach described here could be used to propose new biomarkers for diagnosis in diverse clinical settings including dengue infections, asthma and sepsis resolution.

Association between IL-17F rs763780 polymorphism and susceptibility of asthma: a meta-analysis

Published data on the association between interleukin-17F (IL-17F) rs763780 polymorphism and asthma susceptibility are inconclusive. To derive a more precise estimation of this association, a meta-analysis was performed. A literature search was conducted in PubMed, Web of Science, Elsevier, Wanfang, and China National Knowledge Infrastructure (CNKI) databases to identify eligible studies. The pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to calculate the strength of association. Sensitivity analysis was performed to evaluate the influence of individual studies on the overall effect estimates and funnel plots were inspected for indication of publication bias. Seven studies with a total of 4200 subjects were finally identified. Overall, we found no significant association between IL-17F rs763780 polymorphism and asthma susceptibility (G vs. A: OR = 1.08, 95% CI = 0.81-1.44, P = 0.62; GA vs. AA: OR = 1.11, 95% CI = 0.84-1.47, P = 0.47; GG + GA vs. AA: OR = 1.07, 95% CI = 0.79-1.44, P = 0.65). After categorizing studies into different subgroups on the basis of ethnicity and age, there remained no significant association (all P > 0.05). Sensitivity analysis demonstrated the stability of our results and publication bias was not evident. The present meta-analysis, combining all currently available data, suggests that IL-17F rs763780 polymorphism is not associated with the susceptibility of asthma.

Gene polymorphisms of stress hormone and cytokine receptors associate with immunomodulatory profile and psychological measurement

OBJECTIVE

We sought to identify whether stable single nucleotide polymorphisms (SNPs) of various endocrine and immune molecules could be used as biomarkers associated with specific immune alterations and chronic stress measures in normal humans.

METHODS

A total of 207 volunteer participants answered stress questionnaire and gave peripheral blood cells for identification of SNPs in genes coding for glucocorticoid receptor (GR), beta 2 adrenergic receptor (B2AR), interferon-gamma receptors (IFNGR1, IFNGR2), and interleukin-4 receptor (IL4R). Immunoregulatory profiles were measured by flow cytometry and genotyping assays were performed by allelic discrimination real-time PCR.

RESULTS

Several significant differences were revealed in associations between stress marker and immune indicators based on SNP categories. For instance, Th1 levels of the minor alleles of GR TthIIII (AA) and IFNGR2 Q64R (Arg/Arg) groups were positively associated with chronic stress (PSS) (p = 0.024 and 0.005, respectively) compared with wild type (WT) and negatively associated with PSS in the heterozygous genotypes of GR BclI and IL4R Ile50Val (p = 0.040 and p = 0.052, respectively). Treg levels of the minor alleles of BclI (GG) and IFNGR1 T-56C (CC) groups were positively associated with PSS (p = 0.045 and p = 0.010, respectively) and negatively associated in the minor allele (Val/Val) of IL4R Ile50Va and the heterozygous genotype of IL4R Q576R (p = 0.041 and p = 0.017, respectively) compared to WT.

CONCLUSION

The data support the notion that gene polymorphisms from various components of the psychoneuroendocrine-immune network may be useful as biomarkers to categorize individual stress-associated immune responses.

Pooled-analysis of the association between TIM-1 5383_5397 insertion/deletion polymorphism and asthma susceptibility

The T cell immunoglobulin (Ig) domain and mucin domain 1 (TIM-1) gene play an important role in pathogenesis of asthma. We investigate the association between the TIM-1 5383_5397 insertion/deletion polymorphism (rs45623443) and the risk of asthma in an asthma case-control study, and added these data to a literature-based meta-analysis. The TIM-1 5383_5397 insertion/deletion polymorphism genotype was analyzed in 156 asthma patients and 162 healthy subjects from Han Chinese population. We combined our data with that from previously published studies and performed a meta-analysis to evaluate the effect of the gene. Through regression model, we found no significant association for TIM-1 5383_5397 insertion/deletion polymorphism in our cohort. Meta-analysis, comprising a total of 1,577 asthma cases and 1,781 controls, revealed that no significant association between and asthma susceptibility was observed (OR = 0.99, 95 % CI = 0.83-1.20 for Ins vs. Del; OR = 1.01, 95 % CI = 0.74-1.37 for Ins/Ins vs. Ins/Del + Del/Del; OR = 0.96, 95 % CI = 0.78-1.18 for Ins/Ins + Ins/Del vs. Del/Del). The present meta-analysis suggested that TIM-1 5383_5397 insertion/deletion polymorphism may not substantially contribute to asthma susceptibility. However, gene-gene and gene-environment interaction effects and other considerations involving this polymorphism may exit.

Microbial exposure and onset of allergic diseases - potential prevention strategies?

Chronic inflammatory diseases are a major health problem with global dimension. Particularly, the incidence of allergic diseases has been increased tremendously within the last decades. This world-wide trend clearly indicates the demand for new approaches in the investigation of early allergy development. Recent studies underlined the basic postulate of the hygiene hypothesis that early exposure to microbial stimuli plays a crucial role in the prevention of chronic inflammatory conditions in adulthood. There is ample evidence that, both, exogenous microbes and endogenous microbial communities, the human microbiota, shape the developing immune system and might be involved in prevention of pathologic pro-inflammatory trails. According to the Barker hypothesis, epidemiological studies pointed to transmaternal transmission from the mother to the offspring already in prenatal life. Experimental data from murine models support these findings. This state of the art review provides an overview on the current literature and presents new experimental concepts that point out to future application in the prevention of allergic diseases.

ADAM33 polymorphisms are associated with asthma and a distinctive palm dermatoglyphic pattern

A close correlation between asthma and palm dermatoglyphic patterns has been observed in previous studies, but the underlying genetic mechanisms have not been investigated. A disintegrin and metalloprotein-33 (ADAM33) polymorphisms are important in the development of asthma and other atopic diseases. To investigate the underlying mechanisms of the association between asthma and distinctive palm dermatoglyphic patterns, thirteen ADAM33 single-nucleotide polymorphisms (SNPs) were analyzed for the association between asthma and palm dermatoglyphic patterns in a population of 400 asthmatic patients and 200 healthy controls. Based on the results, five SNPs, rs44707 (codominant model, P=0.031; log-additive model, P=0.0084), rs2787094 (overdominant model, P=0.049), rs678881 (codominant model, P=0.028; overdominant model, P=0.0083), rs677044 (codominant model, P=0.013; log-additive model, P=0.0033) and rs512625 (dominant model, P=0.033), were associated with asthma in this population. Two SNPs, rs44707 (dominant model, P=0.042) and rs2787094 (codominant model, P=0.014; recessive model, P=0.0038), were observed in the asthma patients with the distinctive palm pattern. As rs44707 and rs2787094 are associated with asthma and a distinctive palm pattern, the data suggest that ADAM33 polymorphisms are correlated with asthma and may be the underlying genetic basis of the association between asthma and palm dermatoglyphic patterns.

Copy number variation prevalence in known asthma genes and their impact on asthma susceptibility

BACKGROUND

Genetic studies have identified numerous genes reproducibly associated with asthma, yet these studies have focussed almost entirely on single nucleotide polymorphisms (SNPs), and virtually ignored another highly prevalent form of genetic variation: Copy Number Variants (CNVs).

OBJECTIVE

To survey the prevalence of CNVs in genes previously associated with asthma, and to assess whether CNVs represent the functional asthma-susceptibility variants at these loci.

METHODS

We genotyped 383 asthmatic trios participating in the Childhood Asthma Management Program (CAMP) using a competitive genomic hybridization (CGH) array designed to interrogate 20 092 CNVs. To ensure comprehensive assessment of all potential asthma candidate genes, we purposely used liberal asthma gene inclusion criteria, resulting in consideration of 270 candidate genes previously implicated in asthma. We performed statistical testing using FBAT-CNV.

RESULTS

Copy number variation in asthma candidate genes was prevalent, with 21% of tested genes residing near or within one of 69 CNVs. In six instances, the complete candidate gene sequence resides within the CNV boundaries. On average, asthmatic probands carried six asthma-candidate CNVs (range 1-29). However, the vast majority of identified CNVs were of rare frequency (< 5%) and were not statistically associated with asthma. Modest evidence for association with asthma was observed for 2 CNVs near NOS1 and SERPINA3. Linkage disequilibrium analysis suggests that CNV effects are unlikely to explain previously detected SNP associations with asthma.

CONCLUSIONS AND CLINICAL RELEVANCE

Although a substantial proportion of asthma-susceptibility genes harbour polymorphic CNVs, the majority of these variants do not confer increased asthma risk. The lack of linkage disequilibrium (LD) between CNVs and asthma-associated SNPs suggests that these CNVs are unlikely to represent the functional variant responsible for most known asthma associations.

Genetic complexity of the human surfactant-associated proteins SP-A1 and SP-A2

Pulmonary surfactant protein A (SP-A) plays a key role in innate lung host defense, in surfactant-related functions, and in parturition. In the course of evolution, the genetic complexity of SP-A has increased, particularly in the regulatory regions (i.e. promoter, untranslated regions). Although most species have a single SP-A gene, two genes encode SP-A in humans and primates (SFTPA1 and SFTPA2). This may account for the multiple functions attributed to human SP-A, as well as the regulatory complexity of its expression by a relatively diverse set of protein and non-protein cellular factors. The interplay between enhancer cis-acting DNA sequences and trans-acting proteins that recognize these DNA elements is essential for gene regulation, primarily at the transcription initiation level. Furthermore, regulation at the mRNA level is essential to ensure proper physiological levels of SP-A under different conditions. To date, numerous studies have shown significant complexity of the regulation of SP-A expression at different levels, including transcription, splicing, mRNA decay, and translation. A number of trans-acting factors have also been described to play a role in the control of SP-A expression. The aim of this report is to describe the genetic complexity of the SFTPA1 and SFTPA2 genes, as well as to review regulatory mechanisms that control SP-A expression in humans and other animal species.

Genome-wide association studies of asthma in population-based cohorts confirm known and suggested loci and identify an additional association near HLA

RATIONALE

Asthma has substantial morbidity and mortality and a strong genetic component, but identification of genetic risk factors is limited by availability of suitable studies.

OBJECTIVES

To test if population-based cohorts with self-reported physician-diagnosed asthma and genome-wide association (GWA) data could be used to validate known associations with asthma and identify novel associations.

METHODS

The APCAT (Analysis in Population-based Cohorts of Asthma Traits) consortium consists of 1,716 individuals with asthma and 16,888 healthy controls from six European-descent population-based cohorts. We examined associations in APCAT of thirteen variants previously reported as genome-wide significant (P<5 x 10(-8)) and three variants reported as suggestive (P<5× 10(-7)). We also searched for novel associations in APCAT (Stage 1) and followed-up the most promising variants in 4,035 asthmatics and 11,251 healthy controls (Stage 2). Finally, we conducted the first genome-wide screen for interactions with smoking or hay fever.

MAIN RESULTS

We observed association in the same direction for all thirteen previously reported variants and nominally replicated ten of them. One variant that was previously suggestive, rs11071559 in RORA, now reaches genome-wide significance when combined with our data (P = 2.4 × 10(-9)). We also identified two genome-wide significant associations: rs13408661 near IL1RL1/IL18R1 (P(Stage1+Stage2) = 1.1x10(-9)), which is correlated with a variant recently shown to be associated with asthma (rs3771180), and rs9268516 in the HLA region (P(Stage1+Stage2) = 1.1x10(-8)), which appears to be independent of previously reported associations in this locus. Finally, we found no strong evidence for gene-environment interactions with smoking or hay fever status.

CONCLUSIONS

Population-based cohorts with simple asthma phenotypes represent a valuable and largely untapped resource for genetic studies of asthma.

Severe asthma in childhood: recent advances in phenotyping and pathogenesis

PURPOSE OF REVIEW

Children with severe asthma have a high degree of respiratory morbidity despite treatment with high doses of inhaled corticosteroids and are therefore very difficult to treat. This review will discuss phenotypic and pathogenic aspects of severe asthma in childhood, as well as remaining knowledge gaps.

RECENT FINDINGS

As a group, children with severe asthma have a number of distinct phenotypic features compared with children with mild-to-moderate asthma. Clinically, children with severe asthma are differentiated by greater allergic sensitization, increased exhaled nitric oxide, and significant airflow limitation and air trapping that worsens as a function of age. These findings are accompanied by structural airway changes and increased and dysregulated airway inflammation and oxidant stress which may explain the differential nature of corticosteroid responsiveness in this population. Because children with severe asthma themselves are a heterogeneous group, current efforts are focused on improved definition and sub-phenotyping of the disorder. Whereas the clinical relevance of phenotyping approaches in severe asthma is not yet clear, they may provide important insight into the mechanisms underlying the disorder.

SUMMARY

Improved classification of severe asthma through unified definitions, careful phenotypic analyses, and mechanism-focused endotyping approaches may ultimately advance knowledge and personalized treatment.

Genetics of asthma susceptibility and severity

This article summarizes major findings in genome-wide studies of asthma susceptibility and severity. Two large meta-analyses identified four chromosomal regions which were consistently associated with development of asthma. Genes that are associated with asthma subphenotypes such as lung function, biomarker levels, and asthma therapeutic responses can provide insight into mechanisms of asthma severity and disease progression. Future genetic studies will incorporate sequencing in comprehensively phenotyped asthmatics to lead to the development of personalized therapy.

Exposure assessment of residential mould, fungi and microbial components in relation to children's health: achievements and challenges

Each day we are exposed to a complex mixture of microbial agents and components in indoor environments. A major part of this mixture derives from fungal and bacterial origin. The impact between those microbial agents in the home environment in relation to respiratory health in children is still a major issue in research. There is little known about the causal agents that provoke or arrest the development of allergic respiratory disorders in children. Identification is complicated by the biodiversity and variability of microbial components in indoor air as well as the lack of validated and standardized exposure assessment methods. In this review, we aim to consider all important aspects in terms of research which may encounter an epidemiological study. Apart from the need for standardized exposure assessment methods which consider cost, handling and effort, especially for the participants, we suggest that a combination of different analysis methods such as chemical and molecular methods may have the potential to best describe the microbial milieu in indoor environments at present. Further, the impact of mould and moisture remediation activities on health is still heavily under investigated, especially in larger prospective cohorts of children and should be a topic of future research. Moreover, the exposure to mould and microbial agents might be embedded in a broader spectrum of children's health such as behavior and cognitive development.

Genetic variant associations of human SP-A and SP-D with acute and chronic lung injury

Pulmonary surfactant, a lipoprotein complex, maintains alveolar integrity and plays an important role in lung host defense, and control of inflammation. Altered inflammatory processes and surfactant dysfunction are well described events that occur in patients with acute or chronic lung disease that can develop secondary to a variety of insults. Genetic variants of surfactant proteins, including single nucleotide polymorphisms, haplotypes, and other genetic variations have been associated with acute and chronic lung disease throughout life in several populations and study groups. The hydrophilic surfactant proteins SP-A and SP-D, also known as collectins, in addition to their surfactant-related functions, are important innate immunity molecules as these, among others, exhibit the ability to bind and enhance clearance of a wide range of pathogens and allergens. This review focuses on published association studies of human surfactant proteins A and D genetic polymorphisms with respiratory, and non-respiratory diseases in adults, children, and newborns. The potential role of genetic variations in pulmonary disease or pathogenesis is discussed following an evaluation, and comparison of the available literature.

Adult attention deficit hyperactivity disorder is associated with asthma

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is increasingly recognized as a common disorder not only in children, but also in the adult population. Similarly, asthma also has a substantial prevalence among adults. Previous studies concerning a potential relationship between ADHD and asthma have not presented consistent results.

METHODS

A cross-sectional study of 594 adult patients diagnosed with ADHD, compared with 719 persons from the general population. Information was collected between 1997 and 2005 using auto-questionnaires rating past and present symptoms of ADHD, co-morbid conditions, including asthma, and work status.

RESULTS

The prevalence of asthma was significantly higher in the ADHD patient group compared to the controls, 24.4% vs. 11.3% respectively (OR = 2.54, 95% CI 1.89-3.44), and controls with asthma scored higher on ratings of both past and present symptoms of ADHD. Female ADHD patients had a significantly higher prevalence of asthma compared to male ADHD patients (30.9% vs. 18.2%, OR = 2.01, CI 1.36-2.95), but in controls a slight female preponderance was not statistically significant. In both ADHD patients and controls, having asthma was associated with an increased prevalence of symptoms of mood- and anxiety disorders.

CONCLUSIONS

The present findings point to a co-morbidity of ADHD and asthma, and these patients may represent a clinical and biological subgroup of adult patients with ADHD.

Genetic studies of the etiology of asthma

Asthma is a heterogeneous disease for which a strong genetic basis is firmly established. Although the generally accepted definition includes three domains of symptoms (variable airway obstruction, airway hyper-responsiveness, and airway inflammation), there is general agreement that, rather than being a single disease entity, asthma consists of related, overlapping syndromes. A considerable proportion of asthma is IgE-mediated, but the observation that not all individuals with asthma are atopic adds to the heterogeneity. Although a genetic basis for asthma is undeniable, elucidation of polymorphisms that are "causal" is greatly hampered by variability in the clinical phenotype, which is likely due to the multiple molecular mechanisms underlying the complex pathological processes involved in disease development and progression. One objective of this review is to consider progress that has been made to date in gene discovery in the field of asthma, with a focus on the evolution of molecular genetic methods that have led to the discoveries thus far, and with a particular focus on the major advances owed to the published genome-wide association studies (GWAS) on asthma to date. A second objective is to consider a Darwinian approach toward understanding the genetic underpinnings of asthma, including evidence supporting a modified Hygiene Hypothesis, which suggests that there are co-associations between asthma risk polymorphisms and polymorphisms associated with another IgE-mediated disease, schistosomiasis. The overall conclusion is that the huge research efforts and expense committed to asthma genetics have changed the perception about disease etiology in general and the functional relevance of the asthma genes identified thus far in particular.

Epigenetics of asthma

Asthma is caused by both heritable and environmental factors. It has become clear that genetic studies do not adequately explain the heritability and susceptibility to asthma. The study of epigenetics, heritable non-coding changes to DNA may help to explain the heritable component of asthma. Additionally, epigenetic modifications can be influenced by the environment, including pollution and cigarette smoking, which are known asthma risk factors. These environmental trigger-induced epigenetic changes may be involved in skewing the immune system towards a Th2 phenotype following in utero exposure and thereby enhancing the risk of asthma. Alternatively, they may directly or indirectly modulate the immune and inflammatory processes in asthmatics via effects on treatment responsiveness. The study of epigenetics may therefore play an important role in our understanding and possible treatment of asthma and other allergic diseases. This article is part of a Special Issue entitled: Biochemistry of Asthma.

Advances in pediatric asthma in 2010: addressing the major issues

Last year's "Advances in pediatric asthma" concluded with the following statement: "If we can close these [remaining] gaps through better communication, improvements in the health care system and new insights into treatment, we will move closer to better methods to intervene early in the course of the disease and induce clinical remission as quickly as possible in most children." This year's summary will focus on recent advances in pediatric asthma that take steps moving forward as reported in Journal of Allergy and Clinical Immunology publications in 2010. Some of these recent reports show us how to improve asthma management through steps to better understand the natural history of asthma, individualize asthma care, reduce asthma exacerbations, and manage inner-city asthma and some potential new ways to use available medications to improve asthma control. It is clear that we have made many significant gains in managing asthma in children, but we have a ways to go to prevent asthma exacerbations, alter the natural history of the disease, and reduce health disparities in asthma care. Perhaps new directions in personalized medicine and improved health care access and communication will help maintain steady progress in alleviating the burden of this disease in children, especially young children.