The percentage of Tregs and the level of TGF-β in patients with MCI were significantly increased compared with patients with AD-related dementia, which were composed of patients with mild and moderate-to-severe AD-related dementia (for Tregs, the value of p was 0.002; for TGF-β, the value of p was 0.003). Here, TGFB1 is linked to Alzheimer disease.