CD8A and Cognitive impairment: Based on the increase of pro-inflammatory cytokines and Th subsets found in AD brains, this study assesses the proportions of CD8+CD3−IL-17A+IFNγ− Th17 cells, CD8+CD3−IL-17A−IFNγ+ Th1 cells, and CD4+CD127lowCD25+ Tregs in cryopreserved PBMCs of subjects with Alzheimer’s dementia (AD dementia), MCI due to AD (MCIAD), MCI unlikely due to AD (MCIother), and subjects without cognitive impairment (controls).