Establishment and stability of the latent HIV-1 DNA reservoir

TL;DR

This study shows that the HIV-1 DNA reservoir in patients on suppressive ART is mainly stable, originates from viruses active before treatment, and does not involve ongoing replication during therapy.

Contribution

It provides detailed longitudinal analysis demonstrating the stability and origin of HIV-1 DNA reservoirs, challenging the idea of persistent replication during ART.

Findings

Most DNA sequences are similar to pre-ART RNA viruses.

No evidence of evolution in DNA reservoirs during ART.

Suppressive ART halts viral turnover, not ongoing replication.

Abstract

HIV-1 infection currently cannot be cured because the virus persists as integrated proviral DNA in long-lived cells despite years of suppressive antiretroviral therapy (ART). To characterize establishment, turnover, and evolution of viral DNA reservoirs we deep-sequenced the p17gag region of the HIV-1 genome from samples obtained after 3-18 years of suppressive ART from 10 patients. For each of these patients, whole genome deep-sequencing data of HIV-1 RNA populations before onset of ART were available from 6-12 longitudinal plasma samples spanning 5-8 years of untreated infection. This enabled a detailed analysis of the dynamics and origin of proviral DNA during ART. A median of 14% (range 0-42%) of the p17gag DNA sequences were overtly defective due to G-to-A hypermutation. The remaining sequences were remarkably similar to previously observed RNA sequences and showed no evidence of evolution over many years of suppressive ART. Most sequences from the DNA reservoirs were very similar to viruses actively replicating in plasma (RNA sequences) shortly before start of ART. The results do not support persistent HIV-1 replication as a mechanism to maintain the HIV-1 reservoir during suppressive therapy. Rather, the data indicate that viral DNA variants are turning over as long as patients are untreated and that suppressive ART halts this turnover.