As competent presenters of antigen, microglia activated in a classical way express molecules for antigen presentation such as MHC II and its co-stimulatory factors CD40 and CD86, characterized as classical markers of microglia activation in MS and Alzheimer’s disease patients (Gobin et al., 2001; Lehmann et al., 2001; Höftberger et al., 2004). Here, CD86 is linked to early-onset autosomal dominant Alzheimer disease.