Vaccine recipients with undetectable residual viremia at week 8 had higher frequencies of HIV-specific CD4 ( + ) and CD8 ( + ) interferon - producing cells ( undetectable versus detectable residual viremia : 277 versus 161 CD4 ( + ) cells/10 ( 6 ) lymphocytes , P = 0.03 and 1326 versus 669 CD8 ( + ) cells/10 lymphocytes , P = 0.04 ) .