IGHE and hypersensitivity reaction disease: Tree pollen counts have been reported to be higher in the homes of children with allergic sensitization to tree pollen (Matsui et al. 2010; Warner et al. 1990), but the interpretation of such findings remains unclear; in fact, one recent study suggests that quantitative IgE levels can be used as a biomarker for exposure to indoor allergens among sensitized individuals (Matsui et al. 2010).