Elevated cerebrospinal fluid (CSF) levels of soluble TNF receptors is observed in patients with MCI and in AD patients [95], and chronic administration of thalidomide, a well-known TNF-α inhibitor, reduced Aβ load, plaque formation, and BACE1 levels and activity in APP23 transgenic mice [96]. This evidence concerns the gene BACE1 and Alzheimer disease.