Immunoglobulin is important in AD pathology, as illustrated by the significantly lower serum IgG autoantibody level relative to healthy controls (Acharya et al., 2013) although, on the other hand, an inverse correlation was proposed between cerebral Aβ burden and IgM in a mouse model of AD (Wang et al., 2017). This evidence concerns the gene CD40LG and Alzheimer disease.