Maraviroc Abacavir STudy - Effect on Endothelial Recovery

HIV infected patients treated with abacavir might have a higher risk for the occurrence of cardiovascular events. At time of writing of this protocol the underlying mechanism is not yet elucidated, however some studies find impaired endothelial function and elevated markers of chronic inflammation in these patients,suggesting a higher lever of chronic inflammation. Recently maraviroc (Celsentri®), a CCR5-receptor antagonist, became available for treatment of patients infected with HIV-1. Improvement of endothelial function may be a potential beneficial side effect of treatment with maraviroc, due to the potential reduction of immune activation and chronic inflammation as a result of blocking the CCR5-coreceptor. Moreover, treatment intensification of HAART with maraviroc in patients with suppressed plasma HIV\_RNA may decrease plasma HIVRNA below the cut-off of 50 copies/ml as well. The investigators hypothesize that maraviroc intensification therapy in patients on an abacavir-containing regimen will improve endothelial function. The objectives of this study are: First, to assess the effect of addition of maraviroc to an abacavir-containing regimen on endothelial function; second, to assess the effect of this intervention on markers of immune activation and chronic inflammation, and on plasma HIV-RNA below 50 copies/ml.