To determine what happens to SAMHD1 expression during chronic HIV-1 infection, we employed this established flow cytometric method to analyze SAMHD1 expression in CD4+ T cells and CD14+ monocytes from HIV-1 positive patients who were naïve to cART (cART- naïve) and HIV-1-infected patients who received prolonged cART with undetectable plasma HIV-1 levels (referred as cART). The gene discussed is CD4; the disease is HIV-1 infection.