Does ART Adequately Reach Tissue Reservoirs of HIV?
By Jeffrey Laurence, M.D.
A major impediment to an HIV cure is the persistence of cells latently infected with virus. It is possible that the reservoir may expand in tissues if antiretroviral therapy (ART) is not present at sufficient levels to prevent ongoing rounds of viral replication. Existing studies are inconclusive as to whether differences in such drug levels contribute to ongoing HIV growth.
Tissue samples, including biopsies of small intestines, lymph nodes, and rectum were obtained from 19 HIV-infected individuals on potent ART. Drug concentrations were measured in these tissues as well as in the blood plasma. Highly sensitive assays were used to determine the level of HIV replication in samples. Higher drug concentrations were observed in the rectum and intestines compared with lymph nodes, whereas levels of HIV growth were higher in those people with lower concentrations of ART in the rectum.
This study adds to existing research indicating that viral growth continues in tissues where ART concentrations are insufficient to contain it. This may contribute to the persistence of HIV reservoirs and viral rebound during analytic treatment interruption.
Scientists at the amfAR Institute for HIV Cure Research were involved in this study.
Dr. Laurence is amfAR’s senior scientific consultant.