Although children with allergic rhinitis sensitized to HDM are known to have increased levels of allergen-specific serum IgE, the presence of different antibody isotypes in saliva, such as IgE, IgA, and IgG subclasses as well as the relationship between serum and salivary antibodies or among antibody isotypes are not yet well established. The gene discussed is IGHE; the disease is allergic rhinitis.