First, we studied the occurrence of IgE sensitization to HDM and bacterial antigens from S. aureus and E. coli, in a group of patients with AD from Sweden where sensitization to HDM is expected to be less common, as a result of the cold climate.26 This allowed us to evaluate whether sensitization to bacterial antigens is more frequent among HDM‐sensitized patients. This evidence concerns the gene IGHE and Alzheimer disease.