CCTG 590 is a open-label study to evaluate the impact of therapy intensification with Maraviroc (MVC) (a CCR5 inhibitor) to a stable suppressive HIV antiretroviral regimen on the rate of CD4+ T-cell recovery and gene expression profiles. Patients on a stable first-line HIV regimen with continued viral suppression and sub-optimal CD4+ T-cell counts will be eligible for this study. Those who are found to be eligible will have MVC (dose-adjusted to background HIV regimen) added to their current HIV regimen for 24 weeks. After the 24 week intensification, the MVC will be discontinued, the original antiretroviral regimen will be continued and the subjects will be followed for an additional 12 weeks.