IL17A and Alzheimer disease: Remarkably increased Th17-related cytokines, such as IL-17 and IL-21, were observed in the hippocampus, cerebrospinal fluid and serum of AD patients, while decreased IL-10 and IL-35, the immunosuppressive cytokines produced by Treg cells were detected [13], suggesting that the balance between the two subpopulations exerts functions to prevent excessive immune activation and maintain immune homeostasis.