Associations between anti-HSV IgM and plasma Aβ levels were also not modulated by ApoE4 polymorphism in the present study, consistent with at least one previous observation that ApoE4 does not modify the association between HSV seropositivity and risk of AD [5], although other studies have suggested that it might [35], [36], [37]. This evidence concerns the gene APOE and Alzheimer disease.