Rapid Biphasic Decay of Intact and Defective HIV DNA Reservoir During Acute Treated HIV Disease

Antiretroviral therapy (ART) is not a cure. Upon ART cessation, virus rapidly rebounds from latently-infected cells ("the HIV reservoir"). The reservoir is largely stabilized at the time of ART initiation and then decays slowly. Here, leveraging >500 longitudinal samples from 67 people with HIV (PWH) treated during acute infection, we developed a novel mathematical model to predict reservoir decay using the intact proviral DNA assay (IPDA) from peripheral CD4+ T cells. Nonlinear generalized additive models adjusted for initial CD4+ T count, pre-ART viral load, and timing of ART initiation demonstrated rapid biphasic decay of intact DNA (week 0-5: t1/2 ~0.71 months; week 5-24: t1/2 ~3.9 months) that extended out to 1 year of ART, with similar trends for defective DNA. Predicted reservoir decay were faster for participants individuals with earlier timing of ART initiation, higher initial CD4+ T cell count, and lower pre-ART viral load. These estimates are ~5-fold faster than prior reservoir decay estimates among chronic-treated PWH. Thus, these data add to our limited understanding of host viral control at the earliest stages of HIV reservoir stabilization, potentially informing future HIV cure efforts aimed at diverse, global population of PWH initiating ART at varying stages of disease.

A cohort-based study of host gene expression: tumor suppressor and innate immune/inflammatory pathways associated with the HIV reservoir size

The major barrier to an HIV cure is the HIV reservoir: latently-infected cells that persist despite effective antiretroviral therapy (ART). There have been few cohort-based studies evaluating host genomic or transcriptomic predictors of the HIV reservoir. We performed host RNA sequencing and HIV reservoir quantification (total DNA [tDNA], unspliced RNA [usRNA], intact DNA) from peripheral CD4+ T cells from 191 ART-suppressed people with HIV (PWH). After adjusting for nadir CD4+ count, timing of ART initiation, and genetic ancestry, we identified two host genes for which higher expression was significantly associated with smaller total DNA viral reservoir size, P3H3 and NBL1, both known tumor suppressor genes. We then identified 17 host genes for which lower expression was associated with higher residual transcription (HIV usRNA). These included novel associations with membrane channel (KCNJ2, GJB2), inflammasome (IL1A, CSF3, TNFAIP5, TNFAIP6, TNFAIP9, CXCL3, CXCL10), and innate immunity (TLR7) genes (FDR-adjusted q<0.05). Gene set enrichment analyses further identified significant associations of HIV usRNA with TLR4/microbial translocation (q = 0.006), IL-1/NRLP3 inflammasome (q = 0.008), and IL-10 (q = 0.037) signaling. Protein validation assays using ELISA and multiplex cytokine assays supported these observed inverse host gene correlations, with P3H3, IL-10, and TNF-α protein associations achieving statistical significance (p<0.05). Plasma IL-10 was also significantly inversely associated with HIV DNA (p = 0.016). HIV intact DNA was not associated with differential host gene expression, although this may have been due to a large number of undetectable values in our study. To our knowledge, this is the largest host transcriptomic study of the HIV reservoir. Our findings suggest that host gene expression may vary in response to the transcriptionally active reservoir and that changes in cellular proliferation genes may influence the size of the HIV reservoir. These findings add important data to the limited host genetic HIV reservoir studies to date.

Differences in expression of tumor suppressor, innate immune, inflammasome, and potassium/gap junction channel host genes significantly predict viral reservoir size during treated HIV infection

The major barrier to an HIV cure is the persistence of infected cells that evade host immune surveillance despite effective antiretroviral therapy (ART). Most prior host genetic HIV studies have focused on identifying DNA polymorphisms (e.g., CCR5Δ32 , MHC class I alleles) associated with viral load among untreated "elite controllers" (~1% of HIV+ individuals who are able to control virus without ART). However, there have been few studies evaluating host genetic predictors of viral control for the majority of people living with HIV (PLWH) on ART. We performed host RNA sequencing and HIV reservoir quantification (total DNA, unspliced RNA, intact DNA) from peripheral CD4+ T cells from 191 HIV+ ART-suppressed non-controllers. Multivariate models included covariates for timing of ART initiation, nadir CD4+ count, age, sex, and ancestry. Lower HIV total DNA (an estimate of the total reservoir) was associated with upregulation of tumor suppressor genes NBL1 (q=0.012) and P3H3 (q=0.012). Higher HIV unspliced RNA (an estimate of residual HIV transcription) was associated with downregulation of several host genes involving inflammasome ( IL1A, CSF3, TNFAIP5, TNFAIP6, TNFAIP9 , CXCL3, CXCL10 ) and innate immune ( TLR7 ) signaling, as well as novel associations with potassium ( KCNJ2 ) and gap junction ( GJB2 ) channels, all q<0.05. Gene set enrichment analyses identified significant associations with TLR4/microbial translocation (q=0.006), IL-1β/NRLP3 inflammasome (q=0.008), and IL-10 (q=0.037) signaling. HIV intact DNA (an estimate of the "replication-competent" reservoir) demonstrated trends with thrombin degradation ( PLGLB1 ) and glucose metabolism ( AGL ) genes, but data were (HIV intact DNA detected in only 42% of participants). Our findings demonstrate that among treated PLWH, that inflammation, innate immune responses, bacterial translocation, and tumor suppression/cell proliferation host signaling play a key role in the maintenance of the HIV reservoir during ART. Further data are needed to validate these findings, including functional genomic studies, and expanded epidemiologic studies in female, non-European cohorts.

Author Summary

Although lifelong HIV antiretroviral therapy (ART) suppresses virus, the major barrier to an HIV cure is the persistence of infected cells that evade host immune surveillance despite effective ART, "the HIV reservoir." HIV eradication strategies have focused on eliminating residual virus to allow for HIV remission, but HIV cure trials to date have thus far failed to show a clinically meaningful reduction in the HIV reservoir. There is an urgent need for a better understanding of the host-viral dynamics during ART suppression to identify potential novel therapeutic targets for HIV cure. This is the first epidemiologic host gene expression study to demonstrate a significant link between HIV reservoir size and several well-known immunologic pathways (e.g., IL-1β, TLR7, TNF-α signaling pathways), as well as novel associations with potassium and gap junction channels (Kir2.1, connexin 26). Further data are needed to validate these findings, including functional genomic studies and expanded epidemiologic studies in female, non-European cohorts.

Memory CD4+ T cells that co-express PD1 and CTLA4 have reduced response to activating stimuli facilitating HIV latency

Programmed cell death 1 (PD1) and cytotoxic T lymphocyte-associated protein 4 (CTLA4) suppress CD4⁺ T cell activation and may promote latent HIV infection. By performing leukapheresis (n = 21) and lymph node biopsies (n = 8) in people with HIV on antiretroviral therapy (ART) and sorting memory CD4⁺ T cells into subsets based on PD1/CTLA4 expression, we investigate the role of PD1 and CTLA 4 in HIV persistence. We show that double-positive (PD1⁺CTLA4⁺) cells in blood contain more HIV DNA compared with double-negative (PD1⁻CTLA4⁻) cells but still have a lower proportion of cells producing multiply spliced HIV RNA after stimulation as well as reduced upregulation of T cell activation and proliferation markers. Transcriptomics analyses identify differential expression of key genes regulating T cell activation and proliferation with MAF, KLRB1, and TIGIT being upregulated in double-positive compared with double-negative cells, whereas FOS is downregulated. We conclude that, in addition to being enriched for HIV DNA, double-positive cells are characterized by negative signaling and a reduced capacity to respond to stimulation, favoring HIV latency.

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CD4⁺ T cells co-expressing PD1 and CTLA4 (double positive [DP]) are enriched for HIV DNA

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DP cells contain virus that is more resistant to stimulation

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DP cells display differential expression of genes regulating T cell activation

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These features favor persistence of HIV latency in cells co-expressing PD1 and CTLA4

Association of elevated plasma inflammatory biomarker levels with age-related macular degeneration but not cataract in persons with AIDS

OBJECTIVE

To evaluate the relationship between plasma biomarkers of systemic inflammation and incident age-related macular degeneration (AMD) in persons with the AIDS.

DESIGN

Case-control study.

METHODS

Participants with incident intermediate-stage AMD (N = 26) in the Longitudinal Study of the Ocular Complications of AIDS (LSOCA) and controls (N = 60) without AMD. Cryopreserved baseline plasma specimens were assayed for biomarkers of inflammation, including high-sensitivity C-reactive protein (CRP), interleukin (IL)-6, interferon-γ inducible protein (IP)-10, soluble CD14 (sCD14), soluble CD163 (sCD163), and intestinal fatty acid-binding protein (I-FABP).

RESULTS

After adjustment for age, sex, and race/ethnicity, baseline mean ± standard deviation (SD) log10(mg/ml) plasma levels of CRP (0.52 ± 0.60 vs. 0.20 ± 0.43; P = 0.01) and mean ± SD log10(pg/ml) plasma levels of sCD14 (6.31 ± 0.11 vs. 6.23 ± 0.14; P = 0.008) were significantly higher among cases (incident AMD) than among controls (no AMD). There was a suggestion that mean ± SD baseline log10(pg/ml) plasma IL-6 levels (0.24 ± 0.33 vs. 0.11 ± 0.29; P = 0.10) might be higher among cases than controls. In a separate analysis of 548 participants in LSOCA, elevated baseline levels of plasma inflammatory biomarkers were associated with a greater risk of mortality but not with an increased risk of incident cataract.

CONCLUSION

These data suggest that systemic inflammatory biomarkers are associated with incident AMD but not incident cataract in persons with AIDS, and that systemic inflammation may play a role in the pathogenesis of AMD.

Cell-associated HIV RNA has a Circadian Cycle in Males Living with HIV on Antiretroviral Therapy

BACKGROUND

Circadian transcription factors that regulate cell-autonomous circadian clocks can also increase HIV transcription in vitro. We aimed to determine if circadian variation in HIV transcription exists in people living with HIV (PLHIV) on antiretroviral therapy (ART).

METHODS

We performed a prospective observational study of male PLHIV on ART, sampling blood every four hours for 24 hours. Using qPCR, we quantified expression of circadian associated genes, HIV DNA and cell-associated unspliced (CA-US) RNA in peripheral blood CD4+ T-cells. Plasma sex hormones were quantified alongside plasma and salivary cortisol. The primary outcome was to identify temporal variations in CA-US HIV RNA using a linear mixed effect regression framework and maximum likelihood estimation.

RESULTS

Salivary and plasma cortisol, and circadian genes including Clock, Bmal1, and Per3 varied with a circadian rhythm. CA-US HIV RNA and the ratio of CA-US HIV RNA-to-DNA in CD4+ T-cells also demonstrated circadian variations, with no variation in HIV DNA. Circulating oestradiol was highly predictive of CA-US HIV RNA variation in vivo.

CONCLUSION

CA-US HIV RNA in PLHIV on ART varies temporally with a circadian rhythm. These findings have implications for the design of clinical trials and biomarkers to assess HIV cure interventions.

The TLR7 agonist vesatolimod induced a modest delay in viral rebound in HIV controllers after cessation of antiretroviral therapy

Toll-like receptor 7 (TLR7) agonists, in combination with other therapies, can induce sustained control of simian-human immunodeficiency virus (SHIV) or simian immunodeficiency virus (SIV) in nonhuman primates. Here, we report the results of a randomized, double-blind, placebo-controlled phase 1b clinical trial of an oral TLR7 agonist, vesatolimod, in HIV-1-infected controllers on antiretroviral therapy (ART). We randomized participants 2:1 to receive vesatolimod (n = 17) or placebo (n = 8) once every other week for a total of 10 doses while continuing on ART. ART was then interrupted, and the time to viral rebound was analyzed using the Kaplan-Meier method. Vesatolimod was associated with induction of immune cell activation, decreases in intact proviral DNA during ART, and a modest increase in time to rebound after ART was interrupted. The delayed viral rebound was predicted by the lower intact proviral DNA at the end of vesatolimod treatment (13 days after the final dose). Inferred pathway analysis suggested increased dendritic cell and natural killer cell cross-talk and an increase in cytotoxicity potential after vesatolimod dosing. Larger clinical studies will be necessary to assess the efficacy of vesatolimod-based combination therapies aimed at long-term control of HIV infection.

Everolimus, an mTORC1/2 inhibitor, in ART-suppressed individuals who received solid organ transplantation: A prospective study

Pharmacologic inhibition of the mammalian target of rapamycin (mTOR) in the setting of renal transplantation has previously been associated with lower human immunodeficiency virus 1 (HIV-1) DNA burden, and in vitro studies suggest that mTOR inhibition may lead to HIV transcriptional silencing. Because prospective clinical trials are lacking, we conducted an open-label, single-arm study to determine the impact of the broad mTOR inhibitor, everolimus, on residual HIV burden, transcriptional gene expression profiles, and immune responses in HIV-infected adult solid organ transplant (SOT) recipients on antiretroviral therapy. Whereas everolimus therapy did not have an overall effect on cell-associated HIV-1 DNA and RNA levels in the entire cohort, participants who maintained everolimus time-averaged trough levels >5 ng/mL during the first 2 months of therapy had significantly lower RNA levels up to 6 months after the cessation of study drug. Time-averaged everolimus trough levels significantly correlated with greater inhibition of mTOR gene pathway transcriptional activity. Everolimus treatment also led to decreased PD-1 expression on certain T cell subsets. These data support the rationale for further study of the effects of mTOR inhibition on HIV transcriptional silencing in non-SOT populations, either alone or in combination with other strategies. Trial Registration: ClinicalTrials.gov NCT02429869.

Association of Viral Persistence and Atherosclerosis in Adults With Treated HIV Infection

IMPORTANCE

Persons living with HIV (PLWH) have increased risk for cardiovascular disease, and inflammation is thought to contribute to this excess risk. Production of HIV during otherwise effective antiretroviral therapy (ART) has been associated with inflammation.

OBJECTIVE

To determine whether higher levels of viral persistence are associated with atherosclerosis as assessed by changes in carotid artery intima-media thickness (IMT) over time.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study, intima-media thickness, a validated marker of atherosclerosis, was assessed over time in a cohort of treated PLWH with viral suppression. Cell-associated HIV DNA and RNA and change in IMT, adjusted for demographics, cardiovascular risk factors, and HIV-related factors, were examined, as well as which factors were associated with viral persistence. One hundred fifty-two PLWH with undetectable viral loads for at least 6 months before study enrollment were recruited from HIV clinics affiliated with 2 hospitals in San Francisco, California, from January 1, 2003, to December 31, 2012. Data were analyzed from February 7, 2018, to May 12, 2020.

EXPOSURES

Cell-associated HIV RNA and DNA were measured using enriched CD4+ T cells from cryopreserved peripheral blood mononuclear cells.

MAIN OUTCOMES AND MEASURES

Carotid IMT was measured at baseline and the last visit, with a mean (SD) follow-up of 4.2 (2.7) years, using high-resolution B mode ultrasonography. The main study outcomes were baseline IMT, annual IMT progression, and incident plaque, defined as a focal region of carotid IMT of greater than 1.5 mm.

RESULTS

The analysis included 152 PLWH (140 [92.1%] male; median age, 48.5 [interquartile range {IQR}, 43.3-53.7] years). Older age, smoking, medications for hypertension, higher low-density lipoprotein levels, and higher interleukin 6 levels were associated with higher baseline mean IMT, whereas cell-associated HIV DNA (estimate, -0.07% [95% CI, -6.1% to 6.4%]; P = .98), and HIV RNA levels (estimate, -0.8% [95% CI, -5.9% to 4.4%]; P = .75) were not. Levels of HIV RNA (0.017 [95% CI, 0.000-0.034] mm/y; P = .047) and HIV DNA (0.022 [95% CI, 0.001-0.044] mm/y; P = .042) were significantly associated with annual carotid artery IMT progression in unadjusted models only. Both HIV RNA (incidence risk ratio [IRR], 3.05 [95% CI, 1.49-6.27] per IQR; P = .002) and HIV DNA (IRR, 3.15 [95% CI, 1.51-6.57] per IQR; P = .002) were significantly associated with incident plaque, which remained significant after adjusting for demographics, cardiovascular risk factors, and HIV-related factors (IRR for HIV RNA, 4.05 [95% CI, 1.44-11.36] per IQR [P = .008]; IRR for HIV DNA, 3.35 [95% CI, 1.22-9.19] per IQR [P = .02]). Higher C-reactive protein levels were associated with higher cell-associated HIV RNA (estimate, 20.7% [95% CI, 0.9%-44.4%] per doubling; P = .04), whereas higher soluble CD14 levels were associated with HIV DNA (estimate, 18.6% [95% CI, 3.5%-35.8%] per 10% increase; P = .01). Higher soluble CD163 levels were associated with a higher HIV RNA:DNA ratio (difference, 63.8% [95% CI, 3.5%-159.4%]; P = .04).

CONCLUSIONS AND RELEVANCE

These findings suggest that measurements of viral persistence in treated HIV disease are independently associated with incident carotid plaque development. The size and transcriptional activity of the HIV reservoir may be important contributors to HIV-associated atherosclerosis.

Phenotypic analysis of the unstimulated in vivo HIV CD4 T cell reservoir

The latent reservoir is a major barrier to HIV cure. As latently infected cells cannot be phenotyped directly, the features of the in vivo reservoir have remained elusive. Here, we describe a method that leverages high-dimensional phenotyping using CyTOF to trace latently infected cells reactivated ex vivo to their original pre-activation states. Our results suggest that, contrary to common assumptions, the reservoir is not randomly distributed among cell subsets, and is remarkably conserved between individuals. However, reservoir composition differs between tissues and blood, as do cells successfully reactivated by different latency reversing agents. By selecting 8-10 of our 39 original CyTOF markers, we were able to isolate highly purified populations of unstimulated in vivo latent cells. These purified populations were highly enriched for replication-competent and intact provirus, transcribed HIV, and displayed clonal expansion. The ability to isolate unstimulated latent cells from infected individuals enables previously impossible studies on HIV persistence.

Distinct viral reservoirs in individuals with spontaneous control of HIV-1

Sustained, drug-free control of HIV-1 replication is naturally achieved in less than 0.5% of infected individuals (here termed 'elite controllers'), despite the presence of a replication-competent viral reservoir1. Inducing such an ability to spontaneously maintain undetectable plasma viraemia is a major objective of HIV-1 cure research, but the characteristics of proviral reservoirs in elite controllers remain to be determined. Here, using next-generation sequencing of near-full-length single HIV-1 genomes and corresponding chromosomal integration sites, we show that the proviral reservoirs of elite controllers frequently consist of oligoclonal to near-monoclonal clusters of intact proviral sequences. In contrast to individuals treated with long-term antiretroviral therapy, intact proviral sequences from elite controllers were integrated at highly distinct sites in the human genome and were preferentially located in centromeric satellite DNA or in Krüppel-associated box domain-containing zinc finger genes on chromosome 19, both of which are associated with heterochromatin features. Moreover, the integration sites of intact proviral sequences from elite controllers showed an increased distance to transcriptional start sites and accessible chromatin of the host genome and were enriched in repressive chromatin marks. These data suggest that a distinct configuration of the proviral reservoir represents a structural correlate of natural viral control, and that the quality, rather than the quantity, of viral reservoirs can be an important distinguishing feature for a functional cure of HIV-1 infection. Moreover, in one elite controller, we were unable to detect intact proviral sequences despite analysing more than 1.5 billion peripheral blood mononuclear cells, which raises the possibility that a sterilizing cure of HIV-1 infection, which has previously been observed only following allogeneic haematopoietic stem cell transplantation2,3, may be feasible in rare instances.

Gut and blood differ in constitutive blocks to HIV transcription, suggesting tissue-specific differences in the mechanisms that govern HIV latency

Latently-infected CD4+ T cells are widely considered to be the major barrier to a cure for HIV. Much of our understanding of HIV latency comes from latency models and blood cells, but most HIV-infected cells reside in lymphoid tissues such as the gut. We hypothesized that tissue-specific environments may impact the mechanisms that govern HIV expression. To assess the degree to which different mechanisms inhibit HIV transcription in the gut and blood, we quantified HIV transcripts suggestive of transcriptional interference (U3-U5; "Read-through"), initiation (TAR), 5' elongation (R-U5-pre-Gag; "Long LTR"), distal transcription (Nef), completion (U3-polyA; "PolyA"), and multiple splicing (Tat-Rev) in matched peripheral blood mononuclear cells (PBMCs) and rectal biopsies, and matched FACS-sorted CD4+ T cells from blood and rectum, from two cohorts of ART-suppressed individuals. Like the PBMCs, rectal biopsies showed low levels of read-through transcripts (median = 23 copies/106 cells) and a gradient of total (679)>elongated(75)>Nef(16)>polyadenylated (11)>multiply-spliced HIV RNAs(<1) [p<0.05 for all], demonstrating blocks to HIV transcriptional elongation, completion, and splicing. Rectal CD4+ T cells showed a similar gradient of total>polyadenylated>multiply-spliced transcripts, but the ratio of total to elongated transcripts was 6-fold lower than in blood CD4+ T cells (P = 0.016), suggesting less of a block to HIV transcriptional elongation in rectal CD4+ T cells. Levels of total transcripts per provirus were significantly lower in rectal biopsies compared to PBMCs (median 3.5 vs. 15.4; P = 0.008) and in sorted CD4+ T cells from rectum compared to blood (median 2.7 vs. 31.8; P = 0.016). The lower levels of HIV transcriptional initiation and of most HIV transcripts per provirus in the rectum suggest that this site may be enriched for latently-infected cells, cells in which latency is maintained by different mechanisms, or cells in a "deeper" state of latency. These are important considerations for designing therapies that aim to disrupt HIV latency in all tissue compartments.

CD56negCD16+ NK cells are mature NK cells generated from CD56+CD16+ NK cells during HIV-1 infection (P4438)

A subset of CD3negCD56negCD16+ Natural Killer (NK) cells is highly expanded during chronic HIV-1 infection, and the role of this subset in HIV-1 pathogenesis remains unclear. The lack of NK cell lineage-specific markers has complicated the study of minor NK cell subpopulations. Using CD7 as an additional NK cell marker, we found that CD3negCD56negCD16+ cells are a mixed population of CD7+ NK cells and CD7neg myeloid cells. CD7+CD56negCD16+ NK cells are significantly expanded in HIV-1 infection. CD7+CD56negCD16+ NK cells are mature and express KIRs, NKG2A, NKG2C, and natural cytotoxicity receptors similar to CD7+CD56+CD16+ cells. CD7+CD56neg NK cells in healthy donors produced minimal IFNg following K562 target cell or IL-12 plus IL-18 stimulation; however, they did degranulate in response to K562 cells similar to CD7+CD56+ NK cells. HIV-1 infection resulted in reduced IFNg secretion following K562 or cytokine stimulation by both NK cell subsets compared to healthy donors. Decreased granzyme B and perforin expression and increased expression of CD107a in the absence of stimulation, particularly in HIV-1-infected subjects, suggests that CD7+CD56negCD16+ NK cells may have recently engaged target cells. CD7+CD56negCD16+ NK cells have increased expression of the aging-related cyclin-dependent kinase inhibitors p16/INK4a and p21/Waf1. Taken together, CD7+CD56negCD16+ NK cells appear to be mature NK cells generated from chronic target engagement.

A new subset of CD57+NKG2Chi NK cells is observed after HCMV infection infection (108.4)

During human cytomegalovirus (HCMV) infection, there is a preferential expansion of Natural Killer (NK) cells expressing the activating CD94-NKG2C receptor complex, implicating this receptor in the recognition of HCMV-infected cells. We recently showed that CD57+ NK cells within the CD56dimCD16+ NK cell compartment are highly mature. We hypothesized that human NK cells previously expanded in response to viruses or other pathogens will be marked by expression of CD57. Indeed, we observed in HCMV+ donors that NK cells expressing the activating NKG2C receptor are preferentially CD57+. These CD57+NKG2Chi NK cells have down-regulated the inhibitory NKG2A receptor and some inhibitory KIRs. These CD57+NKG2Chi NK cells respond better to activation through the NKG2C receptor. Furthermore, CD57+NKG2Chi NK cells expressed high amounts of LIR-1, another receptor that recognizes HCMV. Finally, in solid organ transplant recipients with symptomatic HCMV infection the percentage of CD57+NKG2Chi NK cells among the total NK cell population increased as the HCMV plasma viral load decreased. In these patients the NKG2C+ NK cells expanded and proliferated before becoming NKG2Chi and acquiring CD57 expression. Together, these results suggest that during HCMV infection, NKG2C+ NK cells expand to fight the infection, and after several divisions acquire CD57. In humans CD57 might provide a marker of "memory" or "terminally differentiated" NK cells that have been expanded in response to infection.