However, CD8 T cells are known to infiltrate the epidermis in Pso but not in AD24,25 and consistent with this notion, 10.8% of all CD8-positive cells were found in the epidermis in Pso, whereas in AD biopsies only 1% of all CD8-positive cells were located in the epidermis (Fig. 5E, F). This evidence concerns the gene CD8A and Alzheimer disease.