Comparison of HIV-1 DNA load measurements in blood and in relation to successful proviral sequencing

Objective: HIV DNA sequencing is now routinely used for HIV-infected individuals on antiretroviral therapy (ART) with or without partial genotypic history. Successful amplification of HIV pol gene has yet to be correlated with HIV DNA levels. Here, we assessed the relationship between HIV DNA load and sequencing results. Methods: We analyzed three different qPCR measurements of total (LTR and LTR-gag) and integrated (Alu-LTR) HIV DNA in blood samples collected from viremic as well as virally suppressed HIV-infected individuals on ART. HIV DNA levels were compared to HIV DNA Sanger sequencing and clinical and therapeutic parameters. Results: Among the 135 individuals analyzed for HIV DNA measurements and sequencing, all three HIV DNA measurements were associated with HIV DNA Sanger sequencing results. A threshold of around 2 and 1.5 log copies/million leukocytes of total HIV DNA was identified for LTR and LTR-gag qPCRs, respectively. Integrated HIV DNA positivity was also associated with successful sequencing. We further compared HIV DNA measurement techniques in an extended cohort of 312 individuals and showed that all measurements correlated between the different techniques, regardless of the HIV-1 subtypes analyzed. However, higher detection rates were observed with LTR (96%) compared to LTR-gag (86%) and Alu-LTR (59%) qPCRs. Duration of virological control on ART and CD4 nadir were the main determinants of HIV reservoir size. Conclusions: HIV DNA measurement is associated with Sanger sequencing success, regardless of the technique used. In a clinical setting, Application of HIV DNA quantification before sequencing should be further evaluated.