PER2 and HIV infectious disease: Finally, we tested the efficacy of YK-3-237, a more specific Sirt-1 targeting drug, to reduce Per2 expression on CD34 cells [fold of decrease: YK-3-237 0.01 μM: 0.99 (0.97–1.02) vs. 1 μM:1.04 (1.02–1.07, p < 0.03)], confirming the involvement of the Sirt1 in the regulation of Per2 in HPC during chronic HIV infection.