Detection of replication-competent human immunodeficiency virus type 1 (HIV-1) in cultures from patients with levels of HIV-1 RNA in plasma suppressed to less than 500 or 50 copies per milliliter

We determined the frequency with which human immunodeficiency virus (HIV) peripheral blood mononuclear cell cultures convert from positive to negative in subjects enrolled in a substudy of AIDS Clinical Trials Group (ACTG) 320, which compared the efficacy of treatment with a combination of indinavir, zidovudine, and lamivudine (indinavir arm) to that of a combination of zidovudine and lamivudine (dual-nucleoside arm). All subjects included for study had positive baseline HIV cultures. Cultures were performed in real time with 10⁷ fresh patient peripheral blood mononuclear cells, using the ACTG consensus method. We found lower rates of positive HIV cultures in the indinavir treatment arm than in the dual-nucleoside treatment arm (64 versus 96% at week 24, P <0.001). Within the indinavir arm of the study, we found that positive cultures were less likely to occur in samples with a plasma HIV type 1 (HIV-1) RNA level of