IGHE and allergic disease: Besides the MHC class I, II, and III region on ECA20 containing genes that have critical functions in immunity (extensively discussed by [17]), no obvious candidate genes that are involved in the Th2 driven IgE production and induction of allergic disease were detected in close proximity to the identified regions significantly associated with allergen-specific IgE levels or previous GWA analyses based on case-control status.