CD4 and HIV infectious disease: The selected participants had excellent control of their HIV infection as 97% of the participants had undetectable HIV RNA levels (less than 20 copies/mL) and the remaining 3% had detectable HIV RNA but the viral load was very low (~30 copies/mL) with the mean CD4+ lymphocyte count being 743 per cubic millimeters (SD = 333) (Table 1).