This 92 patient randomized, blinded placebo controlled trial plans to investigate the impact of the addition of maraviroc to on-going successful PI/r based ART, with regards to multiple immunology markers including markers of activation, CD4 and CD8 T-cell subsets, immune function (Elispot and lymphoproliferative responses to HIV-1 and recall antigens and/or peptides (Gag, TTox, CMV), and antibody response to oral (cholera) and deep subcutaneous/IM (meningococcus) neoantigens and recall antigens (Tetanus toxoid)) and to assess function of CD4 TFH cells by measuring cytokine and co-stimulatory protein expression in this subset. Delayed type hypersensitivity will be tested at baseline and week 24, and read 48 hours post administration of the Mantoux test.