FLG and Alzheimer disease: Adults with AD who are colonized with S. aureus have more severe disease, and greater T helper type 2 (Th2) immune deviation, allergen sensitization and barrier dysfunction than noncolonized patients with AD.86 Some studies have found that filaggrin mutations are associated with S. aureus colonization in AD, but others have not.86, 87, 88 The increased susceptibility to S. aureus colonization and infection in AD is multifactorial and driven by both skin barrier abnormalities and innate and adaptive immune responses (Fig. 7).