Genome-wide association analysis of eosinophilic esophagitis provides insight into the tissue specificity of this allergic disease

Eosinophilic esophagitis (EoE) is a chronic inflammatory disorder associated with allergic hypersensitivity to food. We interrogated >1.5 million genetic variants in EoE cases of European ancestry and subsequently in a multi-site cohort with local and out-of-study control subjects. In addition to replicating association of the 5q22 locus (meta-analysis P=1.9×10(-16)), we identified an association at 2p23 spanning CAPN14 (P=2.5×10(-10)). CAPN14 was specifically expressed in the esophagus, was dynamically upregulated as a function of disease activity and genetic haplotype and after exposure of epithelial cells to interleukin (IL)-13, and was located in an epigenetic hotspot modified by IL-13. Genes neighboring the top 208 EoE-associated sequence variants were enriched for esophageal expression, and multiple loci for allergic sensitization were associated with EoE susceptibility (4.8×10(-2)<P<5.1×10(-11)). We propose a model to explain the tissue-specific nature of EoE that involves the interplay of allergic sensitization with an EoE-specific, IL-13-inducible esophageal response involving CAPN14.

Severe respiratory syncytial virus infection in early life is associated with increased type 2 cytokine production in Gambian children

BACKGROUND

Severe respiratory syncytial virus (RSV) infection in early childhood has been associated with subsequent wheezing and atopy. The aim of this study was to test if severe RSV infection in early life was associated with an increase in type 2 cytokine production and atopy in Gambian children 5 years later.

METHODS

A cohort of children with severe RSV infection during the first year of life ('cases', n = 66) and without ('controls', n = 122) was followed-up at 5 years of age. Immediate hypersensitivity to common allergens, airway reactivity, serum IgE concentration and the production of IFN-gamma, IL-5 and IL-13 by lymphocytes activated in vitro with RSV F-G or control antigens was determined.

RESULTS

After adjustment for confounders, cases produced significantly higher concentrations of IL-13 in response to RSV F-G and of IL-5 and IL-13 in response to tuberculin. Cases were more likely to have presented with a wheezy lower respiratory tract infection in the first 3 years of life (adjusted odds ratio = 9.9; 95% CI 1.6-61.0), but not thereafter. Cases and controls had similar skin response to allergens, airway reactivity and serum IgE concentrations.

CONCLUSION

Severe RSV infection in early life is associated with a higher production of type 2 cytokines in Gambian children at 5 years of age. However this does not appear to result in increased risk of atopy or clinical allergy at that age.