Gut epithelial barrier dysfunction, innate immune activation, inflammation, and coagulation-but not T-cell activation, senescence, and exhaustion-independently predict mortality in individuals with treated HIV infection with a history of AIDS and are viable targets for interventions.

Immune activation that appears related to exposure to microbial elements distinguishes immune failure from immune success in treated HIV infection.

The advent of combination antiretroviral therapy (cART) has significantly improved the prognosis of HIV-infected individuals. However, individuals treated long term with cART still manifest increased mortality compared to HIV-uninfected individuals. This increased mortality is closely associated with inflammation, which persists in cART-treated HIV-infected individuals despite levels of plasma viremia being below detection limits. Chronic, pathological immune activation is a key factor in progression to AIDS in untreated HIV-infected individuals. One contributor to immune activation is microbial translocation, which occurs when microbial products traverse the tight epithelial barrier of the gastrointestinal tract. Here we review the mechanisms underlying microbial translocation and its role in contributing to immune activation and disease progression in HIV infection.