The HIV virus still replicates in lymphoid tissue even when it is undetectable in blood among patients taking antiretroviral therapies, according to researchers from Northwestern University. Findings from the study are published in Nature

Steven Wolinsky, MD, chief of infectious diseases at Northwestern’s Feinberg School of Medicine and colleagues examined viral sequences in serial samples of cells from lymph nodes and blood from 3 HIV-infected patients with undetectable virus in their blood. 

Their viral reservoir was constantly replenished by low-level virus replication in lymphoid tissue with infected cells, which were then migrating into the blood. Because the infected cells can still produce new viruses, infect new cells, and constantly replenish the reservoir, eradicating all the latently infected cells and viruses has not been possible. The team used a mathematical model to to track the amount of virus and infected cells that grew and turned into drug “sanctuaries.”

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The findings noted a new viewpoint on how HIV persists in the body even with strong antiretroviral therapy and why drug resistance is not evident when virus growth occurs in an area where drug concentrations are very low. Further, the findings indicate the importance in delivering high concentrations of antiretroviral therapy to all locations where HIV can grow. 


1. Lorenzo-Redondo R, Fryer HR, Bedford T, et al. Persistent HIV-1 replication maintains the tissue reservoir during therapy. Nature, 2016; DOI:10.1038/nature16933

This article originally appeared on MPR