Sustained CD4(+) T cell response after virologic failure of protease inhibitor-based regimens in patients with human immunodeficiency virus infection

The relationship between plasma human immunodeficiency virus (HIV) RNA leve ls and peripheral CD4(+) T cell counts was examined in 380 HIV-infected adu lts receiving long-term protease inhibitor therapy. Patients experiencing v irologic failure (persistent HIV RNA >500 copies RNA/mL) generally had CD4( +) T cell counts that remained greater than pretherapy baseline levels, at least through 96 weeks of follow-up. The CD4(+) T cell response was directl y and independently related to degree of viral suppression below the pretre atment baseline. For any given HIV RNA level measured 12 weeks after virolo gic failure, subsequent CD4(+) T cell decline was slower in patients receiv ing a protease inhibitor-based regimen than in a historical control group o f untreated patients. These observations suggest that transient or partial declines in plasma HIV RNA levels can have sustained effects on CD4(+) T ce ll levels.