Interactive effect of STAT6 and IL13 gene polymorphisms on eczema status: results from a longitudinal and a cross-sectional study

BACKGROUND: Eczema is a prevalent skin disease that is mainly characterized by systemic deviation of immune response and defective epidermal barrier. Th2 cytokines, such as IL-13, and transcription factor STAT6 are key elements in the inflammatory response that characterize allergic disorders, including eczema. Previous genetic association studies showed inconsistent results for the association of single nucleotide polymorphisms (SNPs) with eczema. Our aim was to investigate whether SNPs in IL13 and STAT6 genes, which share a biological pathway, have an interactive effect on eczema risk.METHODS: Data from two independent population-based studies were analyzed, namely the Isle of Wight birth cohort study (IOW; n = 1,456) and for the purpose of replication the Swansea PAPA (Poblogaeth Asthma Prifysgol Abertawe; n = 1,445) cross-sectional study. Log-binomial regressions were applied to (i) account for the interaction between IL13 (rs20541) and STAT6 (rs1059513) polymorphisms and (ii) estimate the combined effect, in terms of risk ratios (RRs), of both risk factors on the risk of eczema.RESULTS: Under a dominant genetic model, the interaction term [IL13 (rs20541) x STAT6 (rs1059513)] was statistically significant in both studies (IOW: adjusted Pinteraction = 0.046; PAPA: Pinteraction = 0.037). The assessment of the combined effect associated with having risk genotypes in both SNPs yielded a 1.52-fold increased risk of eczema in the IOW study (95% confidence interval (CI): 1.05 -- 2.20; P = 0.028) and a 2.01-fold higher risk of eczema (95% CI: 1.29 -- 3.12; P = 0.002) in the PAPA study population.CONCLUSIONS: Our study adds to the current knowledge of genetic susceptibility by demonstrating for the first time an interactive effect between SNPs in IL13 (rs20541) and STAT6 (rs1059513) on the occurrence of eczema in two independent samples. Findings of this report further support the emerging evidence that points toward the existence of genetic effects that occur via complex networks involving gene-gene interactions (epistasis)

Longitudinal assessment of Allergic Outcomes and Atopic Dermatitis Phenotypes in The Children\u27s Respiratory and Environmental Workgroup (CREW) Birth Cohort Consortium

Rationale: Atopic dermatitis (AD) is a heterogenous inflammatory skin disease often associated with other allergic diseases. We characterized AD phenotypes and associated allergic outcomes longitudinally across a multi-site consortium. Methods: AD expression in 11 U.S. birth cohorts from the CREW (Children’s Respiratory and Environmental Workgroup) consortium was assessed in each year of life from age 0-7 years (N=7,900). Longitudinal Latent Class Analysis was performed to identify AD phenotypes. Five classes of AD were identified: Persistent AD (15.4%), Early AD with Potential Reoccurrence (2.7%), Late-Onset AD (7.0%), Transient Early AD (3.0%), and Minimal/No AD (72.0%). Serum allergen sensitization patterns and allergic clinical disease were associated with AD phenotype using multinomial logistic regression with a 3-step procedure to account for uncertainty in class membership. Results: Children with Persistent AD, Early AD with Potential Reoccurrence, and Transient Early AD were more likely to have food allergy compared to those with Minimal/No AD (OR[95% CI]=2.73[2.15, 3.45], 2.69[1.63, 4.45], 2.54[1.55, 4.16], respectively). These groups had similarly higher odds of food sensitization. Persistent AD (OR[95% CI]=1.81[1.48, 2.21]) and Early AD with Potential Reoccurrence (OR[95% CI]=3.66[1.90, 7.05]) had significantly higher odds of ever asthma relative to Minimal/No AD. At both 2-4 years and 5-7 years, persistent AD (OR[95% CI]=1.35[1.04, 1.74], 1.25[1.01, 1.53]) and Late-Onset AD (OR[95% CI]=1.68[1.13, 2.50], 2.22[1.33, 3.70]) relative to Minimal/No AD had higher odds of allergic rhinitis. Conclusions: Longitudinal AD phenotypes had varying associations with allergic sensitization, food allergy, asthma and allergic rhinitis, demonstrating the heterogeneity of allergic comorbidity risk associated with AD

Longitudinal Characterization of Atopic Dermatitis Phenotypes in The Children\u27s Respiratory and Environmental Workgroup (CREW) Birth Cohort Consortium

Rationale: Previously identified longitudinal patterns of atopic dermatitis (AD) may lack generalizability and precision due to small sample size and limited time points. We identify and describe longitudinal AD phenotypes in a large consortium study. Methods: Data from 11 birth cohorts across the United States from the CREW (Children’s Respiratory and Environmental Workgroup) consortium were harmonized to determine physician diagnosis of AD in each year of life from 0-7 years of age (N=7,900). AD phenotypes were identified using Longitudinal Latent Class Analysis, and relationships with demographic variables were determined using multinomial logistic regression with a 3-step procedure to account for uncertainty in class membership. Results: We identified 5 classes of AD expression, selected based on model fit, interpretability, and clinical utility: Persistent AD (15.4%), Early AD with Potential Reoccurrence (2.7%), Late-Onset AD (7.0%), Transient Early AD (3.0%), and Minimal/No AD (72.0%). Males had significantly higher odds of Persistent AD (OR [95% CI]=1.47 [1.22, 1.75]) and Early AD with Potential Reoccurrence (OR [95% CI]=1.89 [1.19, 2.94]). Relative to White children, Black children had higher odds of Persistent AD (OR [95% CI]=2.50 [2.05, 3.05]), Early AD with Potential Reoccurrence (OR [95% CI]=3.07 [1.94, 4.85]), and Transient Early AD (OR [95% CI]=4.12 [2.62, 6.48]). Conclusions: Five AD phenotypes exist in a diverse national sample of children. Black children and males are at increased risk of early and persistent AD. These findings illustrate potential risk factors to target AD prevention

The Pediatric Asthma Risk Score: A New Gold Standard for Asthma Prediction

Rationale: Early prediction of asthma is critical to identify potential primary prevention strategies. The Pediatric Asthma Risk Score (PARS) is a continuous score to predict early-life asthma but was developed and validated in relatively homogenous populations. We compared PARS directly to the Asthma Predictive Index (API) and validated in 10 cohorts with varying race, ethnicity, sex, cohort type, missing data and birth decades, and perform a meta-analysis across all 10 cohorts. Methods: We utilized data from 5674 children participating in the Children’s Respiratory and Environmental Workgroup. We applied both PARS and the API in each cohort, as well as harmonized across all cohorts, and directly compared the ability of each tool to predict asthma development at ages 5-10. Results: The PARS area under the curve (AUC) was significantly higher than the AUC of the API in 9 cohorts (p-value range 0.01 - \u3c0.001). The PARS AUC did not differ by cohort type (high risk or general population), decade of enrollment, race, sex, ethnicity, missing PARS factors or polysensitization definition (skin prick test vs. specific IgE). The weights of the 6 PARS factors in the meta-analysis were very similar to the original weights, validating the original PARS scoring. Conclusions: This multi-cohort study makes the PARS the most validated model of asthma prediction in children to date, not only with respect to the number of cohorts used but also with regards to capturing the diversity of asthma in the United States. Future studies may consider PARS the new gold standard in pediatric asthma risk prediction

A Pediatric Asthma Risk Score to better predict asthma development in young children

BACKGROUND: Asthma phenotypes are currently not amenable to primary prevention or early intervention because their natural history cannot be reliably predicted. Clinicians remain reliant on poorly predictive asthma outcome tools because of a lack of better alternatives.OBJECTIVE: We sought to develop a quantitative personalized tool to predict asthma development in young children.METHODS: Data from the Cincinnati Childhood Allergy and Air Pollution Study (n = 762) birth cohort were used to identify factors that predicted asthma development. The Pediatric Asthma Risk Score (PARS) was constructed by integrating demographic and clinical data. The sensitivity and specificity of PARS were compared with those of the Asthma Predictive Index (API) and replicated in the Isle of Wight birth cohort.RESULTS: PARS reliably predicted asthma development in the Cincinnati Childhood Allergy and Air Pollution Study (sensitivity = 0.68, specificity = 0.77). Although both the PARS and API predicted asthma in high-risk children, the PARS had improved ability to predict asthma in children with mild-to-moderate asthma risk. In addition to parental asthma, eczema, and wheezing apart from colds, variables that predicted asthma in the PARS included early wheezing (odds ratio [OR], 2.88; 95% CI, 1.52-5.37), sensitization to 2 or more food allergens and/or aeroallergens (OR, 2.44; 95% CI, 1.49-4.05), and African American race (OR, 2.04; 95% CI, 1.19-3.47). The PARS was replicated in the Isle of Wight birth cohort (sensitivity = 0.67, specificity = 0.79), demonstrating that it is a robust, valid, and generalizable asthma predictive tool.CONCLUSIONS: The PARS performed better than the API in children with mild-to-moderate asthma. This is significant because these children are the most common and most difficult to predict and might be the most amenable to prevention strategies.</p

Interplay of filaggrin loss-of-function variants, allergic sensitization, and eczema in a longitudinal study covering infancy to 18 years of age

BackgroundImmune specific genes as well as genes regulating the formation of skin barrier are major determinants for eczema manifestation. There is a debate as to whether allergic sensitization and filaggrin gene (FLG) variants lead to eczema or FLG variants and eczema increase the risk of allergic sensitization. To investigate the time-order between eczema and allergic sensitization with respect to FLG variants, data from a large prospective study covering infancy to late adolescence were analyzed.Methodology/Principal FindingsRepeated measurements of eczema and allergic sensitization (documented by skin prick tests) at ages 1, 2, 4, 10, and 18 years were ascertained in the Isle of Wight birth cohort (n = 1,456). Three transition periods were analyzed: age 1-or-2 to 4, 4 to 10, and 10 to 18 years. FLG variants were genotyped in 1,150 participants. Over the three transition periods, in temporal sequence analyses of initially eczema-free participants, the combined effect of FLG variants and allergic sensitization showed a 2.92-fold (95% CI: 1.47–5.77) increased risk ratio (RR) of eczema in subsequent examinations. This overall risk was more pronounced at a younger age (transition period 1-or-2 to 4, RR = 6.47, 95% CI: 1.96–21.33). In contrast, FLG variants in combination with eczema showed a weaker, but significant, risk ratio for subsequent allergic sensitization only up to 10 years of age.Conclusions/SignificanceTaking the time order into account, this prospective study demonstrates for the first time, that a combination of FLG variants and allergic sensitization increased the risk of eczema in subsequent years. Also FLG variants interacted with eczema and increased the risk of subsequent allergic sensitization, which, was limited to the younger age. Hence, early restoration of defective skin barrier could prevent allergic sensitization and subsequently reduce the risk of eczema development.<br/

Identification of ATPAF1 as a novel candidate gene for asthma in children

Background:Asthma is a common disease of children with a complex genetic origin. Understanding the genetic basis of asthma susceptibility will allow disease prediction and risk stratification. Objective:We sought to identify asthma susceptibility genes in children. Methods:A nested case-control genetic association study of children of Caucasian European ancestry from a birth cohort was conducted. Single nucleotide polymorphisms (SNPs, n = 116,024) were genotyped in pools of DNA samples from cohort children with physician-diagnosed asthma (n = 112) and normal controls (n = 165). A genomic region containing the ATPAF1 gene was found to be significantly associated with asthma. Additional SNPs within this region were genotyped in individual samples from the same children and in 8 independent study populations of Caucasian, African American, Hispanic, or other ancestries. SNPs were also genotyped or imputed in 2 consortia control populations. ATPAF1 expression was measured in bronchial biopsies from asthmatic patients and controls. RESULTS: Asthma was found to be associated with a cluster of SNPs and SNP haplotypes containing the ATPAF1 gene, with 2 SNPs achieving significance at a genome-wide level (P = 2.26 × 10(-5) to 2.2 × 10(-8)). Asthma severity was also found to be associated with SNPs and SNP haplotypes in the primary population. SNP and/or gene-level associations were confirmed in the 4 non-Hispanic populations. Haplotype associations were also confirmed in the non-Hispanic populations (P = .045-.0009). ATPAF1 total RNA expression was significantly (P &lt; .01) higher in bronchial biopsies from asthmatic patients than from controls. Conclusion:Genetic variation in the ATPAF1 gene predisposes children of different ancestries to asthma