Intensification of a Suppressive HAART Regimen Increases CD4 Counts and Decreases CD8+ T-cell Activation

A significant proportion of HIV-1-infected individuals on suppressive HAART regimens do not reconstitute CD4 counts well. If viral reservoirs persist and impact on CD4 reconstitution in a percentage of cases then addition of another antiretroviral agent could further suppress these reservoirs resulting in enhanced CD4 recovery. To evaluate this possibility, we studied the effect of adding abacavir to a chronically suppressive NNRTI containing HAART regimen for 8 patients on their CD4 count and expression of activation markers. Over the first 24 weeks of intensification, CD4 counts increased significantly (p=0.028). This increase continued after a year in follow-up with a significant rate of change in CD4 T-cells of 0.959+/-1.27 per week. In addition, during intensification changes in the percentage of CD38+CD8+ T-cells over time were significantly negatively correlated with changes in CD4 cell number over time above increases predicted without intensification (r(2)=0.716, p=0.008). These data support the possibility that in certain cases where suboptimal CD4 reconstitution occurs that intensification of the regimen can impact immunologic parameters.