Genetic factors may be involved, as suggested by familial inheritance of disease, association between atopy and specific human leukocyte antigen (HLA) loci, and polymorphisms of several genes, including those for the high-affinity IgE receptor beta-chain, IL-4 receptor alpha-chain, interleukin (IL) - 4, IL-13, CD14, dipeptidyl-peptidase 10 (DPP10), and a disintegrin and metalloprotease domain 33 (ADAM33).