Genes upregulated only in uninvolved skin of patients with AD included Son of sevenless homolog 2 (Drosophlia) (SOS2), PIP (binding to CD4, exerting an immunosuppressive effect),26 mediator complex subunit 16 (MED16), mucin 1, cell surface associated (MUC1), insulin-like growth factor binding protein 5 (IGFBP5), and fatty acid desaturase 1 (FADS1) (Table 3). Here, CD4 is linked to Alzheimer disease.