In contrast, HSV1 DNA has been found in human brain by seven independent groups, including the author’s, the latter using three different methods: solution and in situ PCR, and immunological (Of the sole contradictory studies, two detected HSV1 DNA in only a very small percentage of subjects, and the third showed only a trend for HSV1-APOE-ε4 association conferring a risk of AD; these and the HSV1-positive findings were reviewed by Wozniak and Itzhaki, 2010). Here, APOE is linked to Alzheimer disease.