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Shared DNA methylation signatures in childhood allergy: The MeDALL study.

The Journal of allergy and clinical immunology

Authors: Cheng-Jian Xu, Olena Gruzieva, Cancan Qi, Ana Esplugues, Ulrike Gehring, Anna Bergström, Dan Mason, Leda Chatzi, Daniela Porta, Karin C Lodrup Carlsen, Nour Baïz, Anne-Marie Madore, Harri Alenius, Bianca van Rijkom, Soesma A Jankipersadsing, Pieter van der Vlies, Inger Kull, Marianne van Hage, Mariona Bustamante, Aitana Lertxundi, Matias Torrent, Gillian Santorelli, Maria Pia Fantini, Vegard Hovland, Giancarlo Pesce, Nanna Fyhrquist, Tiina Laatikainen, Martijn C Nawijn, Yang Li, Cisca Wijmenga, Mihai G Netea, Jean Bousquet, Josep M Anto, Catherine Laprise, Tari Haahtela, Isabella Annesi-Maesano, Kai-Håkon Carlsen, Davide Gori, Manolis Kogevinas, John Wright, Cilla Söderhäll, Judith M Vonk, Jordi Sunyer, Erik Melén, Gerard H Koppelman

BACKGROUND: Differential DNA methylation associated with allergy might provide novel insights into the shared or unique etiology of asthma, rhinitis, and eczema.

OBJECTIVE: We sought to identify DNA methylation profiles associated with childhood allergy.

METHODS: Within the European Mechanisms of the Development of Allergy (MeDALL) consortium, we performed an epigenome-wide association study of whole blood DNA methylation by using a cross-sectional design. Allergy was defined as having symptoms from at least 1 allergic disease (asthma, rhinitis, or eczema) and positive serum-specific IgE to common aeroallergens. The discovery study included 219 case patients and 417 controls at age 4 years and 228 case patients and 593 controls at age 8 years from 3 birth cohorts, with replication analyses in 325 case patients and 1111 controls. We performed additional analyses on 21 replicated sites in 785 case patients and 2124 controls by allergic symptoms only from 8 cohorts, 3 of which were not previously included in analyses.

RESULTS: We identified 80 differentially methylated CpG sites that showed a 1% to 3% methylation difference in the discovery phase, of which 21 (including 5 novel CpG sites) passed genome-wide significance after meta-analysis. All 21 CpG sites were also significantly differentially methylated with allergic symptoms and shared between asthma, rhinitis, and eczema. The 21 CpG sites mapped to relevant genes, including ACOT7, LMAN3, and CLDN23. All 21 CpG sties were differently methylated in asthma in isolated eosinophils, and 10 were replicated in respiratory epithelium.

CONCLUSION: Reduced whole blood DNA methylation at 21 CpG sites was significantly associated with childhood allergy. The findings provide novel insights into the shared molecular mechanisms underlying asthma, rhinitis, and eczema.

Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.

PMID: 33338541

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