The presence of infiltrating monocytes has been probed by: (i) the upregulation of genes rarely expressed by microglial cells and abundant in monocytes (such as CD163, MSR1, CCR2, F13A1), (ii) the increase in the proportion of positive Cd163 cells in the parenchyma from AD samples, and (iii) the clear association of Cd163 positive cells with Abeta plaques from AD samples but not with those from non-demented age-matched individuals (Braak II, CERAD B). This evidence concerns the gene MSR1 and Alzheimer disease.