Upon allergen challenge, METS-exposed murine offspring express significantly higher levels of Th2 cytokines in BAL fluid and lung, lung eosinophilia and airway hyperreactivity when compared to offspring exposed to ambient air antenatally [114, 115] which corresponds with strong hypomethylation at the IL4 and IL13 promoters [114]. This evidence concerns the gene IL13 and Increased total eosinophil count.