BACKGROUND. HIV-1 viremia that is not suppressed by combination antiretroviral therapy (ART) is generally attributed to incomplete medication adherence and/or drug resistance. We evaluated individuals referred by clinicians for nonsuppressible viremia (plasma HIV-1 RNA above 40 copies/mL) despite reported adherence to ART and the absence of drug resistance to the current ART regimen. METHODS. Samples were collected from at least 2 time points from 8 donors who had nonsuppressible viremia for more than 6 months. Single templates of HIV-1 RNA obtained from plasma and viral outgrowth of cultured cells and from proviral DNA were amplified by PCR and sequenced for evidence of clones of cells that produced infectious viruses. Clones were confirmed by host-proviral integration site analysis. RESULTS. HIV-1 genomic RNA with identical sequences were identified in plasma samples from all 8 donors. The identical viral RNA sequences did not change over time and did not evolve resistance to the ART regimen. In 4 of the donors, viral RNA sequences obtained from plasma matched those sequences from viral outgrowth cultures, indicating that the viruses were replication competent. Integration sites for infectious proviruses from those 4 donors were mapped to the introns of the MATR3, ZNF268, ZNF721/ABCA11P, and ABCA11P genes. The sizes of the clones were estimated to be from 50 million to 350 million cells. CONCLUSION. These findings show that clones of HIV-1-infected cells producing virus can cause failure of ART to suppress viremia. The mechanisms involved in clonal expansion and persistence need to be defined to effectively target viremia and the HIV-1 reservoir.

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HIV persists during antiretroviral therapy (ART) as integrated proviruses in cells descended from a small fraction of the CD4+ T cells infected prior to the initiation of ART. To better understand what controls HIV persistence and the distribution of integration sites (IS), we compared about 15,000 and 54,000 IS from individuals pre-ART and on ART, respectively, with approximately 395,000 IS from PBMC infected in vitro. The distribution of IS in vivo is quite similar to the distribution in PBMC, but modified by selection against proviruses in expressed genes, by selection for proviruses integrated into one of 7 specific genes, and by clonal expansion. Clones in which a provirus integrated in an oncogene contributed to cell survival comprised only a small fraction of the clones persisting in on ART. Mechanisms that do not involve the provirus, or its location in the host genome, are more important in determining which clones expand and persist.

Background SARS-CoV-2 viral RNA (vRNA) is detected in the bloodstream of some patients with COVID-19 (“RNAemia”) but it is not clear whether this RNAemia reflects viremia (i.e., virus particles) and how RNAemia/viremia is related to host immune responses and outcomes. Methods SARS-CoV-2 vRNA was quantified by ultra-sensitive RT-PCR in plasma samples (0.5-1.0 ml) from observational cohorts of 51 COVID-19 patients including 9 outpatients, 19 hospitalized (non-ICU), and 23 ICU patients, and vRNA levels compared with cross-sectional indices of COVID-19 severity and prospective clinical outcomes. We used multiple imaging methods to visualize virions in pelleted plasma. Results SARS-CoV-2 vRNA was detected in plasma of 100%, 52.6% and 11.1% of ICU, non-ICU, and outpatients respectively. Virions were detected in plasma pellets by electron tomography and immunostaining. Plasma vRNA levels were significantly higher in ICU > non-ICU > outpatients (p<0.0001); and for inpatient, plasma vRNA levels were strongly associated with higher WHO score at admission (p=0.01), maximum WHO score (p=0.002) and discharge disposition (p=0.004). A plasma vRNA level >6,000 copies/ml was strongly associated with mortality (HR: 10.7). Levels of vRNA were significantly associated with several inflammatory biomarkers (p<0.01) but not with plasma neutralizing antibody titers (p=0.8). Conclusions Visualization of virus particles in plasma indicates that SARS-CoV-2 RNAemia is due, at least in part, to viremia. The levels of SARS-CoV-2 RNAemia quantified by ultrasensitive RT-PCR correlate strongly with disease severity, patient outcome and specific inflammatory biomarkers but not neutralizing antibody titers.