KRT9 and HIV infectious disease: We applied this assay successfully to measure absolute abundances of the histone H3 K9[Poy]K14[Poy] and K9[Poy]K14[Ac] peptides in hMDM samples obtained from six donors that were HIV-infected only (control-infected-control, CIC), Meth exposed after HIV infection (control-infected-Meth, CIM), and exposed to Meth pre- and post- HIV infection (Meth-infected-Meth, MIM), and to calculate the stoichiometry of the H3 K14Ac in the respective conditions for those donors (Fig. 2).