IL17A and Alzheimer disease: Research has shown that the Th17/Th1/Treg ratio is imbalanced in elderly patients with Alzheimer’s disease, with elevated levels of IL-17 and reduced levels of IL-10 detected in their serum and cerebrospinal fluid (CSF) compared to those without the condition; furthermore, an elevated proportion of Tems and decreases in Tregs and TNs have been reported in the sera of these patients [62,85,86,87].