An Epigenome-Wide Association Study of Total Serum Immunoglobulin E Concentration

Abstract

Immunoglobulin E (IgE) is a central mediator of allergic (atopic) inflammation. Therapies directed against IgE benefit hay fever ¹ and allergic asthma ^{1, 2} . Genetic association studies have not yet identified novel therapeutic targets or pathways underlying IgE regulation ^{3- 6} . We therefore surveyed epigenetic association between serum IgE concentrations and methylation at loci concentrated in CpG islands (CGI) genome-wide in 95 nuclear pedigrees, using DNA from peripheral blood leukocytes (PBL). We validated positive results in additional families and in subjects from the general population. We show here replicated associations with a meta-analysis false discovery rate <10 ⁻⁴ between IgE and low methylation at 36 loci. Genes annotated to these loci encode known eosinophil products, and also implicate phospholipid inflammatory mediators, specific transcription factors, and mitochondrial proteins. We confirmed that methylation at these loci differed significantly in isolated eosinophils from subjects with and without high IgE levels. The top three loci accounted for 13% of IgE variation in the primary subject panel, explaining 10 fold higher variance than that derived from large SNP GWAS ^{3, 4} . The study identifies novel therapeutic targets and biomarkers for patient stratification for allergic diseases.