Concurrent measures of total and integrated HIV DNA monitor reservoirs and ongoing replication in eradication trials.

OBJECTIVES

Interest in targeting HIV reservoirs is fueling trials that may decrease reservoir size and/or induce viral replication. Therefore, we aimed to develop strategies to sensitively measure changes in these parameters in patients on and off antiretroviral therapy (ART). Achieving these goals may help evaluate the effects of future clinical trials.

DESIGN

To determine the relationship between measurements of total and integrated HIV DNA and their role as markers of reservoir size and ongoing replication, these parameters were measured during the first year of ART, during long-term effective ART, and during a clinical trial aimed at targeting reservoirs.

METHODS

Total and integrated HIV DNA were measured in patient samples using quantitative PCR techniques. CD4(+)T cell counts and plasma viremia were also monitored.

RESULTS

Unintegrated HIV DNA became undetectable during the first year of ART. Total and integrated HIV DNA levels were generally equal in well controlled patients on ART, and low-level plasma viremia correlated best with integration measures. Finally, patients who controlled plasma viremia (<400 copies/ml) during interferon-α monotherapy exhibited a decrease in the level of integrated but not total HIV DNA and a rise in the ratio of total to integrated HIV DNA over time.

CONCLUSION

Our findings suggest that appearance of unintegrated HIV DNA reflects residual HIV expression and de-novo reverse transcription, providing insight into the mechanism by which interferon-α reduces the HIV reservoir. We conclude that concurrent measurements of total and integrated HIV DNA provide information regarding reservoir size and ongoing replication in trials targeting HIV.