Characterization of viral dynamics in human immunodeficiency virus type 1-infected patients treated with combination antiretroviral therapy: Relationships to host factors, cellular restoration, and virologic end points

Biphasic plasma viral decays were modeled in 48 patients treated with ritonavir, zidovudine, and lamivudine. Estimated first- and second-phase decay rates were d₁ as 0.47/day and d₂ as 0.04/day. Interpatient differences in both decay rates were significant. The d₁ was directly correlated with baseline CD4⁺, CD4⁺CD28⁺, and CD8⁺CD28⁺ T lymphocyte counts (P< .05) and inversely correlated with baseline virus load (P = .044) and the magnitude of CD4⁺ and CD8⁺ T lymphocyte recovery (P<.01). The d₂ was directly correlated with baseline percentage of CD8⁺ T lymphocytes (P = .023), the CD8⁺CD38⁺ cell number (P = .024), and the level of IgG that binds to human immunodeficiency virus (HIV) type 1 gp120 (P = .02). Vital decay rates were not predictive of treatment failure or durability of viral suppression. These exploratory findings are consistent with a model in which immunologic factors contribute to elimination of HIV-infected cells and suggest a dynamic interplay between regulation of HIV expression and lymphocyte activation and recovery.