Atopic dermatitis (AD) is caused by genetic and environmental factors that interact to determine disease susceptibility and severity. Several lines of evidence suggest that the IL-4 gene and the IL-4-receptor alpha (IL-4Ralpha) gene are involved in the development of atopic diseases.
The objective of this study was to evaluate the possible involvement of the chromosomal regions 5q31 and 16p12, which include the genes coding for the IL-4 and the IL-4Ralpha in AD.
We conducted linkage analysis and association studies using the microsatellite markers D16S298 and D16S403 and a single nucleotide polymorphism in the promoter region of the IL-4 gene (- 590C/T) in 406 Swedish families with at least two siblings affected with AD, in total 1514 individuals.
Eczema, asthma, and rhinitis affect a large proportion of children, but their prevalence varies with age. IgE antibodies are also common in the pediatric population. However, the links between IgE, disease, and trajectories are unclear.
To better understand the links between sensitization and disease, we studied IgE sensitization ever in relation to eczema, asthma, and rhinitis, in children followed up to 16 years of age.
From the Swedish population-based birth cohort BAMSE, 2607 children were included. Parental reports from six time points between 1 and 16 years were used to identify children with eczema, asthma, and rhinitis. Blood was collected at 4, 8, and 16 years, and sensitization ever was defined as allergen-specific IgE =0.35 kUA /l to common food and/or inhalant allergens at any time point. Odds ratios for eczema, asthma, rhinitis, and multimorbidity in relation to sensitization ever were calculated using generalized estimating equations.
Fifty-one percent were sensitized at least once up to 16 years. Almost a quarter of ever-sensitized children did not have any disease. After adjustment for potential confounders, sensitization ever was significantly associated with the following: (i) eczema throughout childhood, (ii) multimorbidity of eczema, asthma, and rhinitis from 1 to 16 years (OR for multimorbidity: 5.11, 95% CI: 3.99-6.55), (iii) asthma and rhinitis from 4 to 16 years of age.
Specific IgE is strongly associated with eczema and allergic multimorbidity throughout childhood and with asthma and rhinitis from age 4 years. However, 23% of the children with IgE sensitization do not develop any disease in childhood.
Atopic dermatitis is a hereditary, pruritic, inflammatory and chronic skin disease that typically presents in early childhood and may continue or recur later. The etiology of atopic dermatitis is unknown, but several lines of evidence indicate that it is a multifactorial disorder caused by the combined influence of genetic and environmental factors, even though the relative contributions of genes and environment are not known. To identify important loci that contribute to the development of atopic dermatitis, we conducted a genome-wide linkage analysis with 367 microsatellite markers, using a non-parametric affected relative-pair method in 109 pedigrees. Three qualitative phenotypes and one semi-quantitative phenotype were studied. For the phenotype atopic dermatitis, linkage to chromosome region 3p24-22 was found. For another phenotype, atopic dermatitis combined with raised allergen-specific IgE levels, a suggestive linkage was found to chromosome region 18q21. For the semi-quantitative phenotype severity score of atopic dermatitis, suggestive linkage was found to chromosome regions 3q14, 13q14, 15q14-15 and 17q21. Identifying chromosome regions linked to susceptibility genes for atopic dermatitis provides a platform from which the search for atopic dermatitis genes can proceed.