New tools for quantifying HIV-1 reservoirs: plasma RNA single copy assays and beyond.

Quantification of plasma HIV-1 RNA below the limit of FDA-approved assays by a single copy quantitative PCR assays (SCA) has provided significant insights into HIV-1 persistence despite potent antiretroviral therapy as well as a means to assess the impact of therapeutic strategies, such as treatment intensification, on residual viremia. In this review, we discuss insights gained from plasma HIV-1 RNA SCA and highlight the need for additional assays to characterize better the cellular and tissue reservoirs of HIV-1. Accurate, reproducible, and sensitive assays to quantify HIV-1 reservoirs, before and after therapeutic interventions, are essential tools in the quest for a cure of HIV-1 infection.