IgE, like FEV is associated with “lower lung function” and higher levels of “allergen-specific IgE are associated with risk of asthma [19].” However, IgE may be difficult to measure, as it has a short half-life compared to other “immunoglobulin isotopes” [19,20] and low sensitivity/specificity “for detecting sputum eosinophilia” [19,21]. This evidence concerns the gene IGHE and Increased total eosinophil count.