Specific Aim 1: To determine the relative long-term benefits of immediate vs. early vs. delayed ART initiation. The investigators will study outcomes after 1.5 and 3.5 years in MSM diagnosed with acute or recent HIV infection. The investigators will examine outcomes in 3 groups based on time of ART initiation: a) immediate: during FI-II (N~30), b) early: during FIII-V (N~50) or c) delayed: at 24 weeks after diagnosis (N~80). The investigators anticipate that CD4+ T cell counts and peripheral inflammatory markers in the FIII-V group and the delayed group will approach those in the immediate treatment group (FI-II) over time; in contrast, they expect that those started ART at "early" or "delayed" time points will have persistent changes in the GI microbiome and in the HIV reservoir.