Many patients on Highly Active Antiretroviral Therapy (HAART) are able to achieve a sustained response with viral loads becoming undetectable and staying undetectable, but do not have an increase in their CD4 counts to levels greater than 500. Adding maraviroc to the treatment regimen of these patients may result in an increase in their CD4 counts. As the patient would be continuing their prior regimen, they will likely continue with full control of viral replication.