HIV compartmentalization: a review on a clinically important phenomenon.

Viral diversity plays an important role in the pathogenesis of HIV disease. However, within an individual, HIV can vary substantially from one tissue or cell type to another, thereby creating viral compartments. HIV compartmentalization has been well documented in the brain, cerebrospinal fluid, and genital tract, although there are also data for viral compartmentalization within the gut, lung, liver, kidney, and breast milk. The precise mechanisms that lead to the development of HIV compartmentalization have not been adequately examined but likely include differential immune selection pressures, cell type-specific differences in replication or gene expression, local concentrations of antiviral drugs and/or drug resistance, and co-infections that alter the cellular microenvironment. Identifying and characterizing distinct viral sub-populations enhances our overall understanding of HIV pathogenesis and could ultimately result in the development of novel strategies to impair the ability of these viruses to adapt to and/or infect a given cell/tissue type.