Similarly, HDAC6 (a regulator of immune responses) is a key point in regulating the activation and function of CD8+ T-cell inflammation responses in an AD mouse model (Tsuji et al., 2015) Phenylbutyrate (a kind of HDAC inhibitor) shows therapeutic effects on both acute and chronic skin inflammation via inhibiting local mast cells and activating Tregs in a DNFB-induced AD mouse model (Chung and Pui, 2011). This evidence concerns the gene HDAC9 and Alzheimer disease.