Precise Quantitation of the Latent HIV-1 Reservoir: Implications for Eradication Strategies

The quantitative viral outgrowth assay (QVOA) provides a precise minimal estimate of the reservoir of resting CD4(+) T-cell infection (resting cell infection RCI). However, the variability of RCI over time during antiretroviral therapy (ART), relevant to assess potential effects of latency-reversing agents or other interventions, has not been fully described. We performed QVOA on resting CD4(+) T cells obtained via leukapheresis from 37 human immunodeficiency virus (HIV)-infected patients receiving stable suppressive ART for a period of 6 years. Patients who started ART during acute (n = 17) or chronic (n = 20) HIV infection were studied once HIV RNA levels were 6-fold were rare. We suggest that a 6-fold decline is a relevant threshold to reliably identify effects of antilatency interventions on RCI.