Critically, the long form of CR1, CR1-B, the reported risk allele for Alzheimer’s disease, was associated with a DE gene signature indicating upregulation of pathways labelled ‘cellular infiltration by leukocytes’ and ‘infiltration by neutrophils’; we thus speculate that the association of CR1long with AD might be explained at least in part, by altered immune cell infiltration into the brain. This evidence concerns the gene CR1 and Alzheimer disease.