Dynamics of HIV viremia and antibody seroconversion in plasma donors: implications for diagnosis and staging of primary HIV infection

Autovaccination revisited: potential to boost antiviral immunity and facilitate HIV-1 cure/remission in children

PURPOSE OF REVIEW

To review the concept of autovaccination as a strategy to boost anti-HIV-1 immunity and improve immune control, especially as a means to facilitate cure/remission in paediatric HIV-1 infection, where effective interventions in clinical testing remain limited compared to adults.

RECENT FINDINGS

Early autovaccination studies, conducted 15-25 years ago, suggested potential immunological benefits from exposure to autologous virus in both children and adults, specifically when antiretroviral therapy (ART) was initiated during acute infection. More recent work in nonhuman primates (NHPs) has shown that early ART initiation can significantly reduce the viral setpoint following treatment interruption, primarily through CD8 + T-cell responses, and prevent early immune escape - a phenomenon commonly observed in ART-naive acute infections. Additionally, NHP studies indicate that multiple, short analytical treatment interruptions (ATIs) can delay viral rebound and further lower the viral setpoint via enhanced CD8 + T-cell responses.

SUMMARY

Recent studies in NHP support the potential for autovaccination via short ATIs to enhance antiviral immunity and improve immune control of HIV-1. With well tolerated, well monitored ATI protocols, autovaccination could be a valuable approach to facilitating cure/remission in children living with HIV (LWH), in whom very early-ART initiation and early-life immunity are associated with low viral reservoirs and high cure/remission potential.

Acute retroviral syndrome

PURPOSE OF REVIEW

To review the most important recent literature on the definition, epidemiology, clinical presentation, pathogenesis and treatment of the acute retroviral syndrome (ARS), a constellation of nonspecific symptoms and transient illness occuring in at least 50% of persons shortly after HIV acquisition. ARS is driven by initial rapid HIV viral replication and dissemination after acquisition, followed by immune activation and massive systemic inflammation. A more detailed understanding of ARS is important for the implementation of early detection efforts, treatment and public health strategies to control HIV.

RECENT FINDINGS

Recent research has provided deeper insights into ARS. Key findings include associations of ARS with heightened immune activation and elevated levels of IFNγ and multiple other cytokines, particularly IP-10, as well as with higher viral load and more severe CD4 + depletion during acute infection. These negative impacts can be mitigated by early antiretroviral therapy initiation and long-term outcomes are generally similar in treated individals with or without ARS.

SUMMARY

Current findings underscore the importance of early detection and intervention in ARS to mitigate long-term health impacts and inform the development of targeted therapeutic strategies.

Bird's Eye View on Mycobacterium tuberculosis-HIV Coinfection: Understanding the Molecular Synergism, Challenges, and New Approaches to Therapeutics

Tuberculosis (TB), caused by Mycobacterium tuberculosis (M.tb), is the most common secondary infection in the Human Immunodeficiency Virus (HIV) infected population, accounting for more than one-fourth of deaths in people living with HIV (PLWH). Reciprocally, HIV infection increases the susceptibility to primary TB or reactivation of latent TB by several folds. The synergistic interactions between M.tb and HIV not only potentiate their deleterious impact but also complicate the clinical management of both the diseases. M.tb-HIV coinfected patients have a high risk of failure of accurate diagnosis, treatment inefficiency for both TB and HIV, concurrent nontuberculous mycobacterial infections, other comorbidities such as diabetes mellitus, severe cytotoxicity due to drug overburden, and immune reconstitution inflammatory syndrome (IRIS). The need of the hour is to understand M.tb-HIV coinfection biology and their collective impact on the host immunocompetence and to think of out-of-the-box treatment perspectives, including host-directed therapy under the rising view of homeostatic medicines. This review aims to highlight the molecular players, both from the pathogens and host, that facilitate the synergistic interactions and host-associated proteins/enzymes regulating immunometabolism, underlining potential targets for designing and screening chemical inhibitors to reduce the burden of both pathogens concomitantly during M.tb-HIV coinfection. To appreciate the necessity of revisiting therapeutic approaches and research priorities, we provide a glimpse of anti-TB and antiretroviral drug-drug interactions, project the gaps in our understanding of coinfection biology, and also enlist some key research initiatives that will help us deal with the synergistic epidemic of M.tb-HIV coinfection.

Increasing Sustained Viral Suppression Among Youth Living with HIV: A Randomized Controlled Trial of Stepped Care Intervention

This study aimed to decrease viral load (VL) to increase viral suppression (VS) among youth living with HIV (YLH) ages 12-24. This study was a stepped care randomized controlled trial. Sixty-eight YLH with established infection, without VS, and with at least two follow-ups (N = 68) were randomized to a control condition (n = 25) or a stepped care intervention (n = 43), and repeatedly assessed for up to 24 months. Both conditions received referrals for health services and a daily automated text-messaging and monitoring intervention (AMMI). YLH in stepped care who were unsuppressed at 4-month assessments stepped up to peer support and later to coaching. Random effects regressions examined VL trajectories over time as well as trajectories of secondary outcomes. There was significant evidence suggesting a different longitudinal trajectory of VLs for the two conditions. The control condition had improved VLs at about 12 months and then started to return to higher VLs. The stepped-care condition improved over the same time period and remained relatively stable. We estimated that the average VL was lower in the stepped care condition at 24 months, but we cannot claim a statistically significant difference between conditions. Both intervention groups appeared to have positive intervention impacts suggesting some benefits of the AMMI intervention. The improvement in VL at 24 months for stepped care compared to the control condition are suggestive of a viable intervention strategy that warrants further study.

Activation of CXCR3+ Tfh cells and B cells in lymph nodes during acute HIV-1 infection correlates with HIV-specific antibody development

Lymph node T follicular helper (Tfh) cells and germinal center (GC) B cells are critical to generate potent antibodies but are rarely possible to study in humans. To understand how Tfh/GC B-cell interactions during acute HIV-1 infection (AHI) impact the generation of HIV-specific antibodies, we performed a unique cross-sectional analysis of inguinal lymph node biopsies taken prior to antiretroviral therapy (ART) initiation in AHI. Although total Tfh and GC B cell frequencies did not change during AHI, increased frequencies of proliferating Th1-like CXCR3+ Tfh, CXCR3+ non-GC B cells, and total CXCR3+ GC B cells correlated with gp120-specific IgG antibody levels in AHI. Frequencies of proliferating CXCR3+ Tfh in AHI also correlated with gp120-specific IgG antibody levels after 48 weeks of ART, antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, and increased antibody binding to infected cells after ART. Importantly, while beneficial for antibody development, CXCR3+ Tfh cells were also infected by HIV-1 at higher frequencies than their CXCR3- counterparts and may contribute to the initial dissemination of HIV-1 in follicles. Together, these data suggest that activation of CXCR3+ Tfh cells is associated with induction of the germinal center response and subsequent antibody development, making these cells an important target for future therapeutic interventions.

IMPORTANCE

Early initiation of antiretroviral therapy (ART) is important to limit the seeding of the long-lasting HIV-1 reservoir; however, it also precludes the development of HIV-specific antibodies that can help control the virus if ART is stopped. Antibody development occurs within germinal centers in the lymph node and requires activation of both antigen-specific B cells and T follicular helper cells (Tfh), a specialized CD4+ cell that provides B cell help. To understand how early ART initiation may prohibit antibody development, we analyzed the frequencies and activation status of Tfh and B cells in lymph node biopsies collected in the different stages of acute HIV-1 infection. Our data suggest that decreased antibody development after early ART initiation may be due to limited germinal center development at the time of treatment and that new interventions that target activation of CXCR3+ Tfh may be beneficial to increase long-term HIV-specific antibody levels.

Safety, immunogenicity and effect on viral rebound of HTI vaccines combined with a TLR7 agonist in early-treated HIV-1 infection: a randomized, placebo-controlled phase 2a trial

Building on results from the AELIX-002 trial with HIVACAT T-cell immunogen (HTI)-based vaccines, the AELIX-003 (NCT04364035) trial tested the safety of the combination of ChAdOx1.HTI (C) and MVA.HTI (M), with the TLR7 agonist vesatolimod (VES), in a double-blind, placebo-controlled, randomized clinical trial in 50 virally suppressed early-treated men with HIV-1 infection. Secondary objectives included immunogenicity and effects on viral rebound kinetics during a 24-week antiretroviral treatment interruption (ATI). The most common treatment-related adverse events were mild-to-moderate injection-site pain, influenza-like illness, headache, and fatigue. Strong, broad, and HTI-focused T-cell responses were induced by vaccination. All participants experienced viral rebound in ATI; 33.3% and 23.5% (P = 0.4494) of CCMM + VES and placebo recipients, respectively, remained off antiretroviral therapy for 24 weeks. Post hoc analysis confirmed a correlation between levels of HTI-specific T cells and prolonged time off antiretroviral therapy. The combination of HTI vaccines and VES was safe and elicited robust T-cell responses.

Acute HIV-1 Infection: Paradigm and Singularity

Acute HIV-1 infection (AHI) is a transient period where the virus causes evident damage to the immune system, including an extensive apoptosis of CD4+ T cells associated with a high level of activation and a major cytokine storm to fight the invading virus. HIV infection establishes persistence by integrating the viral genome into host cell DNA in both replicating and non-replicating forms, effectively hiding from immune surveillance within infected lymphocytes as cellular reservoirs. The measurement of total HIV-1 DNA in peripheral blood mononuclear cells (PBMCs) is a reliable reflection of this reservoir. Initiating treatments during AHI with nucleoside reverse transcriptase inhibitors (NRTIs) and/or integrase strand transfer inhibitors (INSTIs) is essential to alter the dynamics of the global reservoir expansion, and to reduce the establishment of long-lived cellular and tissue reservoirs, while preserving and enhancing specific and non-specific immune responses. Furthermore, some of the patients treated at the AHI stage may become post-treatment controllers and should be informative regarding the mechanism of viral control, so patients treated during AHI are undoubtedly the best candidates to test innovative remission strategies toward a functional cure that could play a pivotal role in long-term HIV control. AHI is characterized by high levels of viral replication, with a significant increase in the risk of HIV transmission. Detecting AHI and initiating early treatment following diagnosis provides a window of opportunity to control the epidemic, particularly in high-risk populations.

HIV incident infections during pre-exposure prophylaxis (PrEP) use in Wroclaw, Poland, 2017-2023: a real-life experience

OBJECTIVES

The efficacy of pre-exposure prophylaxis (PrEP) relies on adherence to effective regimens. As data on real-life PrEP roll-out and efficacy from Central and Eastern Europe are scarce, we explored the HIV incident infections among PrEP users in an observational cohort in Poland.

METHODS

A cohort of 887 men having sex with men (MSM) on generic emtricitabine/tenofovir disoproxil (FTC/TDF) were followed for a cumulative 2587 person years (PY). HIV infection was confirmed using molecular and immunoassays, with subtype and genotyping performed at diagnosis. For phylogenetic analysis, we used 2087 HIV-1 A6 partial pol sequences from Poland as background.

RESULTS

Nine (1%) PrEP users acquired HIV during the follow-up period. The estimated HIV incidence was 0.347 per 100 PY, with a relative risk reduction of 90.9%. All users who acquired HIV were cisgender white MSM of European origin (median age: 35.5 years). The majority (eight out of nine) used PrEP on demand (ie, 2-1-1 schedule), with one using PrEP only before receptive and not insertive sexual contacts and seven skipping the double dose. Infections occurred due to inadequate PrEP dosing. In five (55.6%) and four (44.4%) users, subtypes B and A6 were acquired, respectively, with no drug resistance. Each of the four A6 sub-subtypes belonged to distinct clusters. Three of them had distinct regional origins within Poland and one in Ukraine. Users were started on tenofovir alafenamide/emtricitabine/bictegravir at a median of 10.5 days from diagnosis and reached undetectable viral load (<50 copies/mL) at a median of 63 days.

CONCLUSIONS

Overall, FTC/TDF PrEP was very effective, with failures occurring due to suboptimal adherence to on-demand dosing. Effective communication of HIV-related risks and clear instructions on how to use on-demand PrEP without missing doses should be provided to PrEP users. Despite the lack of transmitted drug resistance, we noted a higher number of infections with the A6 subtype and independent lineage introductions.

Longitudinal CNS and systemic T-lymphocyte and monocyte activation before and after antiretroviral therapy beginning in primary HIV infection

Background

Trafficking of immune cells to the central nervous system is hypothesized to facilitate HIV entry and immune-induced neuronal injury and is mediated by surface proteins such as chemokine receptors and α4 integrin. We longitudinally assessed immune cell activation and surface marker expression in cerebrospinal fluid (CSF) and blood and their relationship with CSF HIV RNA beginning during primary HIV infection (PHI) before and after antiretroviral therapy (ART).

Methods

Longitudinal paired blood and CSF were obtained in ART-naïve PHI (<12 month since infection) participants; some independently initiated ART during follow up. Multiparameter flow cytometry of fresh samples determined activation (% CD38+HLADR+) and chemokine receptor expression (% CCR5+ and CXCR3+) on CD4+ and CD8+ T cells, and subtype and α4 integrin expression (% and mean fluorescence intensity (mfi) of CD49d+) on monocytes. HIV RNA was quantified by PCR. Analyses employed Spearman correlation, within-subject correlation, and linear mixed models.

Results

51 participants enrolled at a median 3.2 months post HIV transmission with 168 total visits (113 pre-ART, 55 post-ART) and a median of 6.5 months of longitudinal follow up (range 0-40). In pre-ART PHI, frequencies of activated CD4+ and CD8+ T cells were much higher in CSF than in blood, with levels similar to ART-naïve people with chronic HIV infection. Both CSF CD4+ and CD8+ T cell activation increased longitudinally prior to initiation of ART. In multivariate analysis, CSF CD4+ but not CD8+ T cell activation independently predicted CSF HIV RNA. Neither CSF monocyte subtypes or α4 expression correlated with CSF HIV RNA. Blood monocyte α4 MFI correlated with CD4+ and CD8+ T cell activation (p<0.05). Following ART initiation, blood but not CSF T cell activation declined with days on treatment (slope=-0.06, p=0.001). During ART, blood and CSF monocyte α4 MFI correlated with T cell activation (p<0.05).

Conclusions

In untreated early infection after PHI, immune activation increases over time, and CSF CD4+ T cell activation but not monocyte activation correlates with CSF HIV RNA. Intrathecal T cell activation does not decline during early follow up on ART. Immunomodulating therapies may be needed to prevent neuronal injury and HIV neuroinvasion during early HIV.

Impact of increased diagnosis of early HIV infection and immediate antiretroviral treatment initiation on HIV transmission among men who have sex with men in the Netherlands

The number of new HIV infections among men who have sex with men (MSM) in the Netherlands has been decreasing, but additional efforts are required to bring it further down. This study aims to assess the impact of increased diagnosis of early HIV infection combined with immediate antiretroviral treatment (ART) initiation on reducing HIV transmission among MSM. We developed an agent-based model calibrated to HIV surveillance and sexual behavior data for MSM in the Netherlands in 2017-2022. Starting in 2023, we simulated a 10-year intervention that accelerates HIV diagnosis during the first 3 or 6 months after HIV acquisition across five levels of increased diagnosis rates (2, 4, 8, 16, and 32-fold), followed by immediate ART initiation. The upper limit of the intervention's impact over 10 years is projected to result in the cumulative 298 (95-th QI: 162-451) HIV infections averted. A 32-fold increase in the diagnosis rate within 3 months after HIV acquisition (corresponding to 100% of all new HIV infections diagnosed within 3 months of acquisition) results in 269 (95-th QI: 147-400) infections averted, approaching closely maximum impact. By extending the scope of the intervention to individuals who acquired HIV infection within the previous 6 months, a smaller 8-fold increase in the diagnosis rate (corresponding to 97% of new HIV infections diagnosed within 6 months of acquisition) approaches closely the maximum impact of the intervention by averting 256 (95-th QI: 122-411) HIV infections. Our sensitivity analyses showed that, in an epidemiological context similar to the modern-day the Netherlands, immediate initiation of ART accompanying accelerated diagnosis of individuals with early HIV infection does not significantly affect HIV transmission dynamics. Accelerating early HIV diagnosis through increased awareness, screening, and testing can further reduce transmission among MSM. Meeting this goal necessitates a stakeholder needs assessment.

The primary mechanism for highly potent inhibition of HIV-1 maturation by lenacapavir

Lenacapavir (LEN) is a highly potent, long-acting antiretroviral medication for treating people infected with muti-drug-resistant HIV-1 phenotypes. The inhibitor targets multifaceted functions of the viral capsid protein (CA) during HIV-1 replication. Previous studies have mainly focused on elucidating LEN's mode of action during viral ingress. Additionally, the inhibitor has been shown to interfere with mature capsid assembly during viral egress. However, the mechanism for how LEN affects HIV-1 maturation is unknown. Here, we show that pharmacologically relevant LEN concentrations do not impair proteolytic processing of Gag in virions. Instead, we have elucidated the primary mechanism for highly potent inhibition of HIV-1 maturation by sub-stoichiometric LEN:CA ratios. The inhibitor exerts opposing effects on formation of CA pentamers versus hexamers, the key capsomere intermediates in mature capsid assembly. LEN impairs formation of pentamers, whereas it induces assembly of hexameric lattices by imposing an opened CA conformation and stabilizing a dimeric form of CA. Consequently, LEN treatment results in morphologically atypical virus particles containing malformed, hyper-stable CA assemblies, which fail to infect target cells. Moreover, we have uncovered an inverse correlation between inhibitor potency and CA levels in cell culture assays, which accounts for LEN's ability to potently (with picomolar EC50 values) inhibit HIV-1 maturation at clinically relevant drug concentrations.

The Proviral Reservoirs of Human Immunodeficiency Virus (HIV) Infection

Human Immunodeficiency Virus (HIV) proviral reservoirs are cells that harbor integrated HIV proviral DNA within their nuclear genomes. These cells form a heterogeneous group, represented by peripheral blood mononuclear cells (PBMCs), tissue-resident lymphoid and monocytic cells, and glial cells of the central nervous system. The importance of studying the properties of proviral reservoirs is connected with the inaccessibility of integrated HIV proviral DNA for modern anti-retroviral therapies (ARTs) that block virus reproduction. If treatment is not effective enough or is interrupted, the proviral reservoir can reactivate. Early initiation of ART improves the prognosis of the course of HIV infection, which is explained by the reduction in the proviral reservoir pool observed in the early stages of the disease. Different HIV subtypes present differences in the number of latent reservoirs, as determined by structural and functional differences. Unique signatures of patients with HIV, such as elite controllers, have control over viral replication and can be said to have achieved a functional cure for HIV infection. Uncovering the causes of this phenomenon will bring humanity closer to curing HIV infection, potential approaches to which include stem cell transplantation, clustered regularly interspaced short palindromic repeats (CRISPR)/cas9, "Shock and kill", "Block and lock", and the application of broad-spectrum neutralizing antibodies (bNAbs).

Viral and Immune Risk Factors of HIV Rebound after Interruption of Antiretroviral Therapy

BACKGROUND

Identifying risk factors for HIV rebound after treatment interruption is crucial for designing effective remission strategies.

METHODS

Peripheral blood mononuclear cells from participants in the Zurich HIV Primary Infection Cohort (ZPHI, N=73) and ACTG study A5345 (N=44) were analyzed before ART interruption. We measured cell-associated HIV RNA, total HIV DNA, and proviral diversity (env gene). Immune phenotyping was conducted by flow cytometry. Cox proportional hazards (PH) models and penalized Cox PH models with an adaptive LASSO penalty identified risk factors for time to rebound (HIV RNA >1,000 copies/mL).

RESULTS

Late ART initiation was associated with higher rebound risk (shorter time to rebound), as compared to early ART. Higher pre-ART HIV RNA, total HIV DNA, and increased cellular HIV transcription at the time of ART interruption were associated with higher rebound risk. Higher proviral diversity was associated with higher rebound risk but only among male participants and those enrolled in the ZPHI cohort. Less CD4+ T cells at ART interruption, higher proportions of effector and terminally differentiated T cells, and more activated and exhausted T cells were associated with higher rebound risk, primarily in early treated participants. No significant immunological risk factors were found in participants treated during chronic HIV. In the combined cohort, total HIV DNA and terminally differentiated CD8+ T Cells appeared to be the most relevant risk factors for time to rebound.

CONCLUSION

These findings underscore the importance of early ART initiation and suggest that tailored interventions based on virologic, immunologic, and demographic factors may help achieve sustained viral suppression.

The primary mechanism for highly potent inhibition of HIV-1 maturation by lenacapavir

Lenacapavir (LEN) is a highly potent, long-acting antiretroviral medication for treating people infected with muti-drug-resistant HIV-1 phenotypes. The inhibitor targets multifaceted functions of the viral capsid protein (CA) during HIV-1 replication. Previous studies have mainly focused on elucidating LEN's mode of action during viral ingress. Additionally, the inhibitor has been shown to interfere with mature capsid assembly during viral egress. However, the mechanism for how LEN affects HIV-1 maturation is unknown. Here, we show that pharmacologically relevant LEN concentrations do not impair proteolytic processing of Gag in virions. Instead, we have elucidated the primary mechanism for highly potent inhibition of HIV-1 maturation by sub-stoichiometric LEN:CA ratios. The inhibitor exerts opposing effects on formation of CA pentamers versus hexamers, the key capsomere intermediates in mature capsid assembly. LEN impairs formation of pentamers, whereas it induces assembly of hexameric lattices by imposing an opened CA conformation and stabilizing a dimeric form of CA. Consequently, LEN treatment results in morphologically atypical virus particles containing malformed, hyper-stable CA assemblies, which fail to infect target cells. Moreover, we have uncovered an inverse correlation between inhibitor potency and CA levels in cell culture assays, which accounts for LEN's ability to potently (with pM EC 50 values) inhibit HIV-1 maturation at clinically relevant drug concentrations.

Author Summary

Lenacapavir (LEN) is the first-in-class HIV-1 capsid targeting antiretroviral that exhibits multimodal modality to inhibit both early and late steps of viral replication. Our studies here have elucidated previously undescribed structural and mechanistic bases for a highly potent antiviral activity of LEN during viral egress. These findings will inform clinical applications of LEN as a potent HIV-1 maturation inhibitor and aid the development of second-generation inhibitors targeting assembly of the mature viral capsid.

Dynamics of the blood plasma proteome during hyperacute HIV-1 infection

The complex dynamics of protein expression in plasma during hyperacute HIV-1 infection and its relation to acute retroviral syndrome, viral control, and disease progression are largely unknown. Here, we quantify 1293 blood plasma proteins from 157 longitudinally linked plasma samples collected before, during, and after hyperacute HIV-1 infection of 54 participants from four sub-Saharan African countries. Six distinct longitudinal expression profiles are identified, of which four demonstrate a consistent decrease in protein levels following HIV-1 infection. Proteins involved in inflammatory responses, immune regulation, and cell motility are significantly altered during the transition from pre-infection to one month post-infection. Specifically, decreased ZYX and SCGB1A1 levels, and increased LILRA3 levels are associated with increased risk of acute retroviral syndrome; increased NAPA and RAN levels, and decreased ITIH4 levels with viral control; and increased HPN, PRKCB, and ITGB3 levels with increased risk of disease progression. Overall, this study provides insight into early host responses in hyperacute HIV-1 infection, and present potential biomarkers and mechanisms linked to HIV-1 disease progression and viral load.

A handheld HIV detection platform using paper-based sample preparation and real-time isothermal amplification

Early and accurate diagnosis of human immunodeficiency virus (HIV) infection is essential for timely initiation of antiretroviral therapy (ART) and prevention of new infections. However, conventional nucleic-acid-based tests for HIV detection require sophisticated laboratory equipment and trained personnel, which are often unavailable at the point-of-care (POC) or unaffordable in resource-limited settings. We report our development of a low-cost, integrated platform for POC testing of HIV. The platform integrates viral nucleic acid extraction on a paper substrate and reverse transcription loop-mediated isothermal amplification (RT-LAMP) in a portable, battery-powered heating device with real-time detection. The platform does not require laboratory infrastructure such as power outlets. The assay showed a detection limit of 30 copies/mL of HIV RNA in 140 μL human serum or 4 copies/reaction using 50 μL human serum, with no cross-reactivity with hepatitis C virus (HCV). We validated the platform using both plasma samples spiked with HIV and clinical samples from HIV-positive individuals, and compared it with standard laboratory assays based on polymerase chain reaction (PCR). These results demonstrate the feasibility of our platform for HIV testing at the POC.

Rapid biphasic decay of intact and defective HIV DNA reservoir during acute treated HIV disease

Despite antiretroviral therapy (ART), HIV persists in latently-infected cells (the HIV reservoir) which decay slowly over time. Here, leveraging >500 longitudinal samples from 67 people living with HIV (PLWH) treated during acute infection, we developed a mathematical model to predict reservoir decay from peripheral CD4 + T cells. Nonlinear generalized additive models demonstrated rapid biphasic decay of intact DNA (week 0-5: t1/2 ~ 2.83 weeks; week 5-24: t1/2 ~ 15.4 weeks) that extended out to 1 year. These estimates were ~5-fold faster than prior decay estimates among chronic treated PLWH. Defective DNA had a similar biphasic pattern, but data were more variable. Predicted intact and defective decay rates were faster for PLWH with earlier timing of ART initiation, higher initial CD4 + T cell count, and lower pre-ART viral load. In this study, we advanced our limited understanding of HIV reservoir decay at the time of ART initiation, informing future curative strategies targeting this critical time.

Suppressed HIV antibody responses following exposure to antiretrovirals-evidence from PrEP randomized trials and early antiretroviral treatment initiation studies

BACKGROUND

Exposure to antiretrovirals at or early after HIV acquisition can suppress viral replication and blunt antibody (Ab) responses; a reduced HIV detectability could impact diagnosis and blood donation screening.

METHODS

We used three antigen (Ag)/Ab assays and one nucleic acid test (NAT) to analyze samples collected in pre-exposure prophylaxis (PrEP) trials (iPrEx; Partners PrEP) before infection detection by Ab-only rapid diagnostic tests (RDTs), and in early antiretroviral treatment (ART) initiation studies (RV254; SIPP).

RESULTS

Reactivity using NAT and Ag/Ab assays in samples collected up to 8 weeks prior to the first reactive RDT from 251 PrEP trials participants varied between 49-61% for active PrEP users and between 27-37% for placebo users. Among RV254 participants, reactivity in Ag/Ab assays was <100% at all timepoints, and lower among those initiating ART earlier. Seroreversions occurred for 29% (16/55), and blood donation screening with NAT and Ag/Ab assays could have missed up to 36% (20/55) of RV254 participants. For SIPP participants, who started ART at later timepoints, Ag/Ab assays identified infections with no evidence of reactivity waning.

CONCLUSION

PrEP and early ART initiation can delay or reduce HIV detectability. Considerations for the implementation of NAT and Ag/Ab tests in PrEP/PEP programs relying on Ab-only RDTs should be balanced according to feasibility and public health impact. While blood transfusion services using Ab-only RDTs for HIV screening should adopt higher sensitivity tests, surveillance and further research are needed to determine the need for novel HIV testing algorithms for those already using NAT and Ag/Ab screening assays.

Fourth-Generation HIV Rapid Tests: Enhanced Sensitivity and Reduced Diagnostic Window for HIV-1 Primary Infection Screening

As most HIV rapid tests (HRT) detect only HIV-1/2 antibodies, their performance during primary HIV infection is poor. Determine HIV Early detect (Abbott) (Determine) is the only HRT with an HIV-1 p24-antigen detection, but the impact of this addition in shortening the diagnostic window remains unclear. A total of 183 HIV-1 primary infection samples were tested using the HRTs Determine and ONE STEP anti-HIV (1&2) Test (InTec Products) (One-Step). The pre-seroconversion subgroup was defined as p24-antigen positivity without Western blot nor Liaison XL (fouth generation enzyme immunoassay with distinct signal for p24-antigen and HIV-1 antibody) HIV-1 antibodies. Global sensitivity (95% CI) was 95% (91-97) for Determine versus 80% (74%-85%) for One-Step (difference p = 1.38e-06). Pre-seroconversion subgroup sensitivity was lower, at 71.9 (54.6%-84.4%) for Determine and 9.7% (3.3%-24.9%) for One-Step. Among the 45 samples with an HIV-1 infection date, no HRT was reactive up to 2 weeks. Between 2 and 3 weeks, Determine sensitivity was 78% (45%-95%) versus 56% (27%-81%) for One-Step. From 3 weeks to 1 month Determine sensitivity was 90% (62%-98%) and One-Step 45% (21%-72%). The last negative sample occurred at 3 weeks for Determine versus 70-90 days for One-Step. HRT with p24-antigen detection significantly shortens the diagnostic window from approximatively 3 months to 1 month. HRTs should be used with caution in the first month after HIV infection.

Implementing pathogen reduction technology while discontinuing blood donor deferral criteria for sexual risk behaviors: A simulation study

BACKGROUND

Combining pathogen reduction technology (PRT) with blood screening may alleviate concerns over the risk of transfusion-transmitted infections (TTI) and support changes in blood donor selection to potentially increase blood availability. This study aimed to estimate the residual risk of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) transfusion-transmission in Canada after implementing PRT, while eliminating deferrals for sexual risk behaviors.

STUDY DESIGN AND METHODS

A probabilistic approach that combined Bayesian networks with Monte Carlo simulations was used to estimate the risk of transfusing HIV-, HBV-, or HCV-contaminated blood components. Different scenarios were considered to compare the current residual risk after PRT implementation, with and without donor deferral criteria for sexual risk behaviors. Donor profiles and blood component outcomes were simulated based on a literature review including the prevalence and incidence of HIV, HBV, and HCV in the Canadian blood donor population; the use of current blood screening assays; and HIV, HBV, and HCV blood donor viral loads.

RESULTS

In the universal PRT scenario (i.e., with PRT/without deferral criteria), the estimated risks of HIV, HBV, and HCV transmission were significantly lower than those in the currently observed scenario (i.e., without PRT/with deferral criteria).

CONCLUSIONS

This risk model suggests that PRT for platelets and plasma (and eventually for RBCs when available) significantly reduces the residual risks of HIV, HBV and HCV transfusion-transmission and could enable the removal of blood donor deferral criteria for sexual risk behaviors.

Reconciling founder variant multiplicity of HIV-1 infection with the rate of CD4+ decline

HIV-1 transmission precipitates a stringent genetic bottleneck, with 75% of new infections initiated by a single genetic variant. Where multiple variants initiate infection, recipient set point viral load (SpVL) and the rate of CD4+ T cell decline may be elevated, but these findings remain inconsistent. Here, we summarised the evidence for this phenomenon, then tested whether previous studies possessed sufficient statistical power to reliably identify a true effect of multiple variant infection leading to higher SpVL. Next, we combined models of HIV-1 transmission, heritability and disease progression to understand whether available data suggest a faster CD4+ T cell decline would be expected to associated with multiple variant infection, without an explicit dependency between the two. First, we found that most studies had insufficient power to identify a true significant difference, prompting an explanation for previous inconsistencies. Next, our model framework revealed we would not expect to observe a positive association between multiple variant infections and faster CD4+ T cell decline, in the absence of an explicit dependency. Consequently, while empirical evidence may be consistent with a positive association between multiple variant infection and faster CD4+ T cell decline, further investigation is required to establish a causal basis.

Identification of antibody targets associated with lower HIV viral load and viremic control

BACKGROUND

High HIV viral loads (VL) are associated with increased morbidity, mortality, and on-going transmission. HIV controllers maintain low VLs in the absence of antiretroviral therapy (ART). We previously used a massively multiplexed antibody profiling assay (VirScan) to compare antibody profiles in HIV controllers and persons living with HIV (PWH) who were virally suppressed on ART. In this report, we used VirScan to evaluate whether antibody reactivity to specific HIV targets and broad reactivity across the HIV genome was associated with VL and controller status 1-2 years after infection.

METHODS

Samples were obtained from participants who acquired HIV infection in a community-randomized trial in Africa that evaluated an integrated strategy for HIV prevention (HPTN 071 PopART). Controller status was determined using VL and antiretroviral (ARV) drug data obtained at the seroconversion visit and 1 year later. Viremic controllers had VLs <2,000 copies/mL at both visits; non-controllers had VLs >2,000 copies/mL at both visits. Both groups had no ARV drugs detected at either visit. VirScan testing was performed at the second HIV-positive visit (1-2 years after HIV infection).

RESULTS

The study cohort included 13 viremic controllers and 64 non-controllers. We identified ten clusters of homologous peptides that had high levels of antibody reactivity (three in gag, three in env, two in integrase, one in protease, and one in vpu). Reactivity to 43 peptides (eight unique epitopes) in six of these clusters was associated with lower VL; reactivity to six of the eight epitopes was associated with HIV controller status. Higher aggregate antibody reactivity across the eight epitopes (more epitopes targeted, higher mean reactivity across all epitopes) and across the HIV genome was also associated with lower VL and controller status.

CONCLUSIONS

We identified HIV antibody targets associated with lower VL and HIV controller status 1-2 years after infection. Robust aggregate responses to these targets and broad antibody reactivity across the HIV genome were also associated with lower VL and controller status. These findings provide novel insights into the relationship between humoral immunity and viral containment that could help inform the design of antibody-based approaches for reducing HIV VL.

Evaluation of a point-of-care rapid HIV antibody test with insights into acute HIV symptomatology in a population with low prevalence

Many emergency departments (ED) use rapid human immunodeficiency virus (HIV) antibody tests as screening tools, despite limited sensitivity for detecting acute HIV infections. In a 4-year retrospective analysis of 1,192 patients, we evaluated the performance of a third-generation rapid HIV antibody assay tested at point-of-care (POC, Chembio Sure Check HIV 1/2) against in-lab fourth-generation screening (Abbott Architect Ag/Ab Combo). Compared to complete algorithmic testing, the POC test demonstrated a 92.5% sensitivity (95% CI = 84.6-96.5), 98.1% specificity (95% CI = 97.1-98.8), 99.5% negative predictive value (NPV; 95% CI = 98.8-99.8), and a 77.9% positive predictive value (PPV; 95% CI = 68.6-85.1). Notably, the POC test failed to detect 100% (3/3) of acute HIV infections (defined as Fiebig stage 2) and 3.8% (2/52) established HIV infections, where viral loads were 5.9, 6.7, and >7 log10 copies/mL. Symptoms such as fever, nausea/vomiting, malaise, headache, and photophobia were significantly associated with acute HIV infections diagnosed in the ED. The rapid HIV antibody test demonstrated high sensitivity, specificity, and NPV in our study population, reaffirming its effectiveness as a valuable screening tool. However, the low PPV and 100% failure to detect acute HIV infections underscore the importance of prioritizing in-lab fourth-generation HIV antigen/antibody combination immunoassays in cases of suspected acute HIV infection to ensure a timely and accurate diagnosis.

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

Despite antiretroviral therapy (ART), HIV persists in latently-infected cells ("the reservoir") which decay slowly over time. 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 from peripheral CD4+ T cells. Nonlinear generalized additive models demonstrated rapid biphasic decay of intact DNA (week 0-5: t1/2~2.83 weeks; week 5-24: t1/2~15.4 weeks) that extended out to 1 year. These estimates were ~5-fold faster than prior decay estimates among chronic treated PWH. Defective DNA had a similar biphasic pattern, but data were more variable. Predicted intact and defective decay rates were faster for PWH with earlier timing of ART initiation, higher initial CD4+ T cell count, and lower pre-ART viral load. These data add to our limited understanding of HIV reservoir decay at the time of ART initiation, informing future curative strategies targeting this critical time.

Central Nervous System Effects of Early HIV Infection and Consequences of Antiretroviral Therapy Initiation during Acute HIV

HIV infection is a multi-organ disease that involves the central nervous system (CNS). While devastating CNS complications such as HIV-associated dementia and CNS opportunistic infection typically manifest years after HIV acquisition, HIV RNA is readily detected in the cerebrospinal fluid in untreated neuroasymptomatic people with HIV, highlighting that HIV neuroinvasion predates overt clinical manifestations. Over the past two decades, increased awareness of HIV infection within the at-risk population, coupled with the accessibility of nucleic acid testing and modern HIV immunoassays, has made the detection of acute and early HIV infection readily achievable. This review aims to summarize research findings on CNS involvement during acute and early HIV infection, as well as the outcomes following the immediate initiation of antiretroviral therapy during this early stage of infection. The knowledge gap in long-term neuroprotection through early ART within the first year of infection will be discussed.

Impact of antiretroviral therapy during acute or early HIV infection on virologic and immunologic outcomes: results from a multinational clinical trial

OBJECTIVE

To assess how antiretroviral therapy (ART) initiation during acute or early HIV infection (AEHI) affects the viral reservoir and host immune responses.

DESIGN

Single-arm trial of ART initiation during AEHI at 30 sites in the Americas, Africa, and Asia.

METHODS

HIV DNA was measured at week 48 of ART in 5 million CD4 + T cells by sensitive qPCR assays targeting HIV gag and pol . Peripheral blood mononuclear cells were stimulated with potential HIV T cell epitope peptide pools consisting of env , gag , nef, and pol peptides and stained for expression of CD3, CD4, CD8, and intracellular cytokines/chemokines.

RESULTS

From 2017 to 2019, 188 participants initiated ART during Fiebig stages I ( n  = 6), II ( n  = 43), III ( n  = 56), IV ( n  = 23), and V ( n  = 60). Median age was 27 years (interquartile range 23-38), 27 (14%) participants were female, and 180 (97%) cisgender. Among 154 virally suppressed participants at week 48, 100% had detectable HIV gag or pol DNA. Participants treated during Fiebig I had the lowest HIV DNA levels ( P  < 0.001). Week 48 HIV DNA mostly did not correlate with concurrent CD4 + or CD8 + T cell HIV-specific immune responses (rho range -0.11 to +0.19, all P  > 0.025). At week 48, the magnitude, but not polyfunctionality, of HIV-specific T cell responses was moderately reduced among participants who initiated ART earliest.

CONCLUSION

Earlier ART initiation during AEHI reduced but did not eliminate the persistence of HIV-infected cells in blood. These findings explain the rapid viral rebound observed after ART cessation in early-treated individuals with undetectable HIV DNA by less sensitive methods.

Development and evaluation of a high-sensitivity RT-PCR lateral flow assay for early detection of HIV-1 infection

Early diagnosis of HIV-1 is crucial to minimize transmission, morbidity, and mortality, particularly for neonates with developing immune systems. This study aimed to develop and evaluate a simplified, high-sensitivity assay for early HIV-1 detection before seroconversion. The assay utilizes reverse-transcription-polymerase chain reaction (RT-PCR) to amplify the HIV-1 RNA protease gene. Digoxigenin (dig)-labeled forward, and biotin-labeled universal reverse primers are used, generating digoxigenin-amplicon-biotin (DAB) products. These products are detected using a lateral flow assay (LFA) containing a conjugated pad with colloidal gold-labeled 6-histidine tag-fused maltose-binding protein-monomeric streptavidin (6HISMBP-mSA-CGC). Anti-dig monoclonal antibody (mAb) and biotinylated-BSA are immobilized in the test and control line zones, respectively. Five plasma samples with known viral load (VL) were used to simulate the efficacy of early HIV-1 detection. RNA extracted from these samples was amplified by RT-PCR using the labeled primers, and DAB products were examined on agarose gel electrophoresis and LFA. RT-PCR from diluted clinical samples yielded visible DNA bands in agarose gel electrophoresis, consistent with positive LFA results. Conversely, negative samples only displayed the control line on LFA. This assay exhibited a limit of detection (LOD) of 82.29 RNA copies/mL, comparable to other nucleic acid amplification tests (NAATs). This novel technique provides a highly sensitive assay for early HIV-1 diagnosis, even with low VL, making it suitable for resource-limited settings.

Rapid tests should be used with caution for HIV-1 primary infection screening

Rapid tests allow outpatient, low cost, reliable, screening for chronic HIV infection. However, data regarding their sensitivity on primary infection remain scarce. The objective of this study was to assess sensitivity of nine HIV rapid tests for primary HIV-1 infection screening. Seventy-five serum samples from patients during HIV-1 primary infection were included. Primary infection was diagnosed by a positive 4th generation ELISA and HIV-1 RNA positivity confirmed by Western blot patterns associated with HIV-1 primary infection. Early seroconversion was defined as the absence of antibodies on HIV-1 Western blot associated with HIV-1 RNA and p24-antigen positivity. An identical sensitivity (95% CI) of 76.7% (65.2-84.2%) was observed for HIV 1/2 STAT-PAK® Assay (STAT-PAK), INSTI™ HIV-1/HIV-2 antibody Test (INSTI), SURE CHECK® HIV 1/2 (SURE CHECK) and MULTISURE HIV rapid test (MULTISURE) with visual reading. Sensitivity was 74.7% (63.8-83.1%) for MULTISURE (automatic reading), 77.0% (66.3-85.1%) for FIRST RESPONSE® Test VIH 1-2.O CARTE (FIRST RESPONSE), 83.8% (73.8-90.5%) for VIKIA HIV1/2® (VIKIA), 88.0% (78.7-93.6%) for Genie™ Fast HIV 1/2 (Genie Fast), 88.6% (79.0-94.1%) for Hexagon HIV (Hexagon), and 92.8% (83.6-96.3%) for Exacto® TEST HIV Pro (Exacto). However, rapid tests performed poorly for the early seroconversion subgroup (n = 14), with sensitivities ranging from 7% (1.3-31.5%) for STAT-PAK, INSTI, SURE CHECK, MULTISURE (automatic reading), to 29% (12-55%) for FIRST RESPONSE, 31% (13-58%) for VIKIA, 43% (21-67%) for Hexagon and 57.1% (32.6-78.6%) for Exacto and Genie Fast. Overall, despite significant discrepancies in sensitivity, HIV rapid tests should be used with caution in the context of a suspected primary infection.

Real-world performance of HIV low viral load values in diagnosing acute HIV infection in a tertiary care hospital in Beijing, China

BACKGROUND

Early diagnosis of HIV infection decreases the time from HIV diagnosis to viral suppression and reduces further HIV transmission. The Chinese Guidelines for the Diagnosis and Treatment of HIV/AIDS (2021 edition) state that an HIV RNA level > 5,000 copies/mL is the threshold for diagnosing HIV infection. The impact of low viral load values on HIV diagnosis needs to be investigated.

METHODS

There were 3455 human immunodeficiency virus (HIV1 + 2) antibody results (immunoblotting method) and 65,129 HIV viral load values at Beijing Youan Hospital from 2019 to 2022. A total of 2434 patients had both antibody confirmatory results and viral load results. The confirmatory antibody results and HIV viral load results of 2434 patients were analyzed to investigate the impact of low viral load values on HIV diagnosis.

RESULTS

Of the 2434 patients who had both confirmatory antibody results and viral load results, the viral load values of 140 patients (5.8%) had viral loads ranging from 40 copies/mL to 5,000 copies/mL before positive confirmatory antibody result, and of these 140 patients, the sample receipt time for the viral load tests of 96 (66.7%) individuals was 1 to 6 days earlier than the corresponding sample receipt time for the confirmatory antibody test. In addition, 34 patients (1.4%) had low viral loads ranging from 40 copies/mL to 1,000 copies/mL before positive confirmatory antibody result.

CONCLUSION

This study revealed that there is a risk of missed diagnosis if a threshold of 5000 copies/mL is used for the diagnosis of HIV infection. These data provide valuable information for the early diagnosis of HIV infection, and our findings have potential benefits for decreasing HIV transmission.

Breakthrough Acute HIV Infections among Pre-Exposure Prophylaxis Users with High Adherence: A Narrative Review

Pre-exposure prophylaxis (PrEP) is a pivotal intervention among HIV prevention strategies. We aimed to narratively revise the topic of HIV acute infection in the setting of PrEP exposure with a focus on diagnostic options, clinical features, and future PrEP perspectives, with a particular focus on users with high adherence to PrEP. We searched the main databases (PubMed, Embase, and Scopus) with the keywords "PrEP" or "Pre-Exposure Prophylaxis" and "HIV" or "PLWH" and "breakthrough" or "acute infection" or "primary infection". We included all randomized clinical trials and non-experimental studies (both case reports and observational studies) ever published. In the present narrative review, we revise the diagnostic challenges related to HIV diagnosis in the setting of PrEP and the clinical characteristics and symptoms of breakthrough infections. We discuss the management of acute HIV infection during PrEP and the new challenges that arise from the use of long-acting drugs for PrEP. Our review underlines that although extremely rare, HIV seroconversions are still possible during PrEP, even in a context of high adherence. Efforts to promptly identify these events must be included in the PrEP follow-up in order to minimize the chance of overlooked HIV breakthrough infections and thus exposure to suboptimal concentrations of antiretrovirals.

Identification of a circulating long non-coding RNA signature panel in plasma as a novel biomarker for the detection of acute/early-stage HIV-1 infection

BACKGROUND

Individuals with acute / early HIV-1 infection are often unaware that they are infected with HIV-1 and may be involved in high-risk behavior leading to transmission of HIV-1. Identifying individuals with acute / early HIV-1 infection is critical to prevent further HIV-1 transmission, as diagnosis can lead to several effective HIV-1 prevention strategies. Identification of disease-stage specific non-viral host biomarkers would be useful as surrogate markers to accurately identify new HIV-1 infections. The goal of this study was to identify a panel of host derived plasma long non-coding RNAs (lncRNAs) that could serve as prognostic and predictive biomarkers to detect early/acute HIV-1 infection.

METHODS

A total of 84 lncRNAs were analyzed in sixteen plasma samples from HIV-1 infected individuals and four healthy controls using the lncRNA PCR-array. Twenty-one lncRNAs were selected and validated in 80 plasma samples from HIV-1 infected individuals [HIV-1 infected patients in the eclipse stage (n = 20), acute stage (n = 20), post-seroconversion p31 negative stage (n = 20), and post-seroconversion p31 positive stage (n = 20) of infection] and 20 healthy controls. The validation study results were used to develop a plasma lncRNA panel that was evaluated in the panel test phase to detect early/acute HIV-1 infection in 52 independent samples.

RESULTS

We identified a lncRNA panel (Pmodel-I) containing eight lncRNAs (DISC2, H19, IPW, KRASP1, NEAT1, PRINS, WT1-AS and ZFAS1) that could distinguish HIV-1 infection from healthy controls with high AUC 0·990 (95% CI 0.972-1.000), sensitivity (98.75%), and specificity (95%). We also found that Pmodel-II and Pmodel-III demonstrates 100% sensitivity and specificity (AUC 1·00; 95%CI:1·00-1·00) and could distinguish eclipse stage and acute stage of HIV-1 infection from healthy controls respectively. Antiretroviral treatment (ART) cumulatively restored the levels of lncRNAs to healthy controls levels.

CONCLUSION

lncRNA expression changes significantly in response to HIV-1 infection. Our findings also highlight the potential of using circulating lncRNAs to detect both the eclipse and acute stages of HIV-1 infection, which may help to shorten the window period and facilitate early detection and treatment initiation. Initiating ART treatment at this stage would significantly reduce HIV-1 transmission. The differentially expressed lncRNAs identified in this study could serve as potential prognostic and diagnostic biomarkers of HIV-1 infection, as well as new therapeutic targets.

Optimization of genetic distance threshold for inferring the CRF01_AE molecular network based on next-generation sequencing

Introduction

HIV molecular network based on genetic distance (GD) has been extensively utilized. However, the GD threshold for the non-B subtype differs from that of subtype B. This study aimed to optimize the GD threshold for inferring the CRF01_AE molecular network.

Methods

Next-generation sequencing data of partial CRF01_AE pol sequences were obtained for 59 samples from 12 transmission pairs enrolled from a high-risk cohort during 2009 and 2014. The paired GD was calculated using the Tamura-Nei 93 model to infer a GD threshold range for HIV molecular networks.

Results

2,019 CRF01_AE pol sequences and information on recent HIV infection (RHI) from newly diagnosed individuals in Shenyang from 2016 to 2019 were collected to construct molecular networks to assess the ability of the inferred GD thresholds to predict recent transmission events. When HIV transmission occurs within a span of 1-4 years, the mean paired GD between the sequences of the donor and recipient within the same transmission pair were as follow: 0.008, 0.011, 0.013, and 0.023 substitutions/site. Using these four GD thresholds, it was found that 98.9%, 96.0%, 88.2%, and 40.4% of all randomly paired GD values from 12 transmission pairs were correctly identified as originating from the same transmission pairs. In the real world, as the GD threshold increased from 0.001 to 0.02 substitutions/site, the proportion of RHI within the molecular network gradually increased from 16.6% to 92.3%. Meanwhile, the proportion of links with RHI gradually decreased from 87.0% to 48.2%. The two curves intersected at a GD of 0.008 substitutions/site.

Discussion

A suitable range of GD thresholds, 0.008-0.013 substitutions/site, was identified to infer the CRF01_AE molecular transmission network and identify HIV transmission events that occurred within the past three years. This finding provides valuable data for selecting an appropriate GD thresholds in constructing molecular networks for non-B subtypes.

Sensitivity and specificity of the new Bio-Rad HIV screening test, Access HIV combo V2

Diagnosing of human immunodeficiency virus (HIV) types 1 and 2 requires a screening with a highly sensitive and specific enzyme immunoassay and a low detection limit for the HIV-1 p24 antigen to minimize the diagnostic window. The objective of the study was to determine the sensitivity, specificity, and p24 limit of detection of the Access HIV combo V2 assay. Retrospective part of sensitivity: 452 HIV-1 positive samples from 403 chronic (9 different HIV-1 group M subtypes, 22 different HIV-1 group M CRFs, and 3 HIV-1 group O), 49 primary HIV-1 infections, 103 HIV-2 positive samples assessed at Pitié-Salpêtrière Hospital, 600 untyped HIV-1, 10 subtype-D, and 159 untyped HIV-2 samples assessed in Bio-Rad Laboratories. Prospective part of clinical specificity: all consecutive samples in two blood donor facilities and Pitié-Salpêtrière (6,570 patients) tested with Access HIV combo V2 and respectively Prism HIV O Plus (Abbott) or Architect HIV Ag/Ab Combo (Abbott) for Ag/Ab screening, and Procleix Ultrio (Gen Probe) for HIV RNA screening. Limit of detection for p24 antigen was assessed on recombinant virus-like particles (10 HIV-1 group M subtypes/CRFs, HIV-1 group O). Sensitivity [95% confidence interval (CI)] of Access HIV combo V2 was 100% (99.63-100) for HIV-1 chronic infection, 100% (98.55-100) for HIV-2 chronic infection, and 100% (93.00-100) for HIV-1 primary infection. Specificity (95% CI) was 99.98 (99.91-100). Limit of detection for p24 antigen was around 0.43 IU/mL [interquartile range (0.38-0.56)], and consistent across the 11 analyzed subtypes/CRFs. Hence, with both high sensitivity and specificity, Access HIV combo V2 is a suitable screening assay for HIV-1/2 infection.

IMPORTANCE

Bio-Rad is one of the leading human immunodeficiency virus (HIV) screening test manufacturers. This laboratory released in 2021 their new version of the Access combo HIV test. However, to date, there have been no studies regarding its performance, especially its limit of detection of the diverse p24 antigen. We present the sensitivity (chronic and primary HIV-1 infection and HIV-2 chronic infection), specificity (blood donors and hospitalized patients), and raw data for the p24/seroconversion panels the manufacturer gave to the European agencies.

Prevalence and incidence of anal high-grade squamous intraepithelial lesions in a cohort of cisgender men and transgender women who have sex with men diagnosed and treated during acute HIV acquisition in Bangkok, Thailand

INTRODUCTION

Men who have sex with men (MSM), especially those living with HIV, are at an increased risk of anal cancer. The prevalence and incidence of its precursor, anal high-grade squamous intraepithelial lesions (HSILs), among MSM who started antiretroviral therapy during acute HIV acquisition are yet to be explored.

METHODS

Participants in an acute HIV acquisition cohort in Bangkok, Thailand, who agreed to take part in this study, were enrolled. All participants were diagnosed and started antiretroviral therapy during acute HIV acquisition. Human papillomavirus (HPV) genotyping and high-resolution anoscopy, followed by anal biopsy as indicated, were done at baseline and 6-monthly visits.

RESULTS

A total of 89 MSM and four transgender women were included in the analyses. Median age at enrolment was 26 years. Baseline prevalence of histologic anal HSIL was 11.8%. With a total of 147.0 person-years of follow-up, the incidence of initial histologic anal HSIL was 19.7 per 100 person-years. Factors associated with incident anal HSIL were anal HPV 16 (adjusted hazards ratio [aHR] 4.33, 95% CI 1.03-18.18), anal HPV 18/45 (aHR 6.82, 95% CI 1.57-29.51), other anal high-risk HPV (aHR 4.23, 95% CI 1.27-14.14), syphilis infection (aHR 4.67, 95% CI 1.10-19.90) and CD4 count <350 cells/mm3 (aHR 3.09, 95% CI 1.28-7.48).

CONCLUSIONS

With antiretroviral therapy initiation during acute HIV acquisition, we found the prevalence of anal HSIL among cisgender men and transgender women who have sex with men to be similar to those without HIV. Subsequent anal HSIL incidence, although lower than that of those with chronic HIV acquisition, was still higher than that of those without HIV. Screening for and management of anal HSIL should be a crucial part of long-term HIV care for all MSM.

Viral Load Dynamics in Plasma and Semen When Antiretroviral Therapy Is Initiated During Early HIV-1 Infection

We assessed human immunodeficiency virus (HIV) load in plasma and semen during primary HIV infection using serial samples of semen and plasma during the first 24 weeks after diagnosis in untreated participants and those who started antiretroviral therapy (ART) immediately at diagnosis. In the absence of treatment, semen viral load was >1000 copies/mL in almost all specimens (83%) collected 2-10 weeks after the estimated date of HIV acquisition and remained >1000 copies/mL in 35% of untreated participants at the last observed time point. Thus, in the absence of ART, semen viral load remained at a level consistent with transmissibility throughout primary infection.

Primary HIV infection features colonic damage and neutrophil inflammation yet containment of microbial translocation

INTRODUCTION

Impairment of the gastrointestinal barrier leads to microbial translocation and peripheral immune activation, which are linked to disease progression. Data in the setting of primary HIV/SIV infection suggest that gut barrier damage is one of the first events of the pathogenic cascade, preceding mucosal immune dysfunction and microbial translocation. We assessed gut structure and immunity as well as microbial translocation in acutely and chronically-infected, combination antiretroviral therapy (cART)-naive individuals.

METHODS

Fifteen people with primary HIV infection (P-HIV) and 13 with chronic HIV infection (C-HIV) c-ART-naive participants were cross-sectionally studied. Gut biopsies were analysed in terms of gut reservoirs (total, integrated and unintegrated HIV DNA); tight junction proteins (E-cadherin, Zonula Occludens-1), CD4 + expression, neutrophil myeloperoxidase (histochemical staining); collagen deposition (Masson staining). Flow cytometry was used to assess γδ T-cell frequency (CD3 + panγδ+Vδ1+/Vδ2+). In plasma, we measured microbial translocation (LPS, sCD14, EndoCAb) and gut barrier function (I-FABP) markers (ELISA).

RESULTS

P-HIV displayed significantly higher tissue HIV DNA, yet neutrophil infiltration and collagen deposition in the gut were similar in the two groups. In contrast, microbial translocation markers were significantly lower in P-HIV compared with C-HIV. A trend to higher mucosal E-cadherin, and gut γδ T-cells was also observed in P-HIV.

CONCLUSION

Early HIV infection features higher HIV DNA in the gut, yet comparable mucosal alterations to those observed in chronic infection. In contrast, microbial translocation is contained in primary HIV infection, likely because of a partial preservation of E-cadherin and mucosal immune subsets, namely γδ T-cells.

Erratum to: Progress Note 2024: Curing HIV; Not in My Lifetime or Just Around the Corner?

[This corrects the article DOI: 10.20411/pai.v8i2.665.].

Demographics of Youth With Newly Diagnosed Acute/Recent HIV Infection in Adolescent Trials Network 147: Early Treatment of Acute HIV Infection

PURPOSE

Gay, bisexual, and other cisgender men who have sex with men, and racial minority youth are at elevated risk of acquiring HIV infection. The Adolescent Trials Network 147 recruited youth with acute/recent HIV-infection for early antiretroviral treatment. The cohort make-up is described here.

METHODS

Treatment-naïve, recently identified HIV + youth, aged 12-24 years, from Los Angeles and New Orleans were recruited from community centers, clinics, social media, and a high-risk seronegative cohort (n = 1,727, the Adolescent Trials Network 149) using point-of-care assays. Acute HIV infection was determined by Fiebig staging. HIV RNA viral load (VL) and CD4 cell counts, along with demographic and behavioral data were assessed at enrollment.

RESULTS

Between July 2017 and July 2021, 103 newly diagnosed youth were enrolled, initiating antiretroviral treatment within a week. Mean age was 20.8 years (standard deviation: 2.4); 90.3% identified as cis male, 83.5% were single or in casual relationships, 71.8% were gay, bisexual, and other cisgender men who have sex with men; 60.2% were Black. One-fourth (24.3%) reported homelessness ever; 10.7% within last 4 months. At enrollment, median plasma VL was 37,313 HIV RNA copies/ml (interquartile range: 5,849-126,162) and median CD4 count 445.5 cells/mm3 (interquartile range: 357-613). 40% of youth reported acute retroviral symptoms before or at enrollment. Acutely infected, seroconverting youth had the highest VL. Sexually transmitted coinfections were present at enrollment in 56% of the cohort, with syphilis being most frequent (39%).

DISCUSSION

Early identification and treatment of HIV can increase positive HIV outcomes. A high sexually transmitted infection burden was present in recently HIV-infected youth. Acute retroviral symptoms were not reported by most participants, demonstrating that broad universal HIV screening is needed for identification of recent infection in youth.

Cerebrospinal fluid pleocytosis is associated with HIV-1 neuroinvasion during acute infection

OBJECTIVE

HIV-1 invades the brain within days post-transmission. This study quantitated cerebrospinal fluid (CSF) white blood cell count (WBC) and investigated whether it associated with plasma and CSF HIV-1 RNA during untreated acute HIV infection (AHI).

DESIGN

Seventy participants underwent lumbar puncture during Fiebig stages I-V AHI.

METHOD

WBC and HIV-1 RNA with a lower limit of quantification (LLQ) of 80 copies/ml were measured in CSF.

RESULTS

Sixty-nine (99%) participants were men, with a median age of 26. Their blood CD4 + and CD8 + T-cell counts were 335 [interquartile range (IQR) 247-553) and 540 (IQR 357-802) cells/μl, respectively. Forty-five (64%) were in Fiebig stages III-V whereas 25 (36%) were in Feibig stages I-II. Fifty-two (74%) experienced acute retroviral syndrome. Median plasma and CSF HIV-1 RNA were 6.10 (IQR 5.15-6.78) and 3.15 (IQR 1.90-4.11) log 10 copies/ml, respectively. Sixteen (23%) CSF samples had HIV-1 RNA below LLQ. Median CSF WBC was 2.5 (IQR 1-8) cells/μl. CSF pleocytosis (WBC >5) was observed in 33% and was only present in CSF samples with detectable HIV-1 RNA. The frequencies of CSF pleocytosis during Fiebig stages III-V and among CSF samples of higher viral load (>1000 copies/ml) were 42 and 45%, respectively. Pleocytosis independently associated with CSF HIV-1 RNA in multivariate analysis [adjusted coefficient: 0.79, 95% confidence interval (CI) 0.41-1.14), P  < 0.001] and a lower plasma to CSF HIV-1 RNA ratio ( P  < 0.001).

CONCLUSION

CSF pleocytosis was present in one-third of participants with AHI. It associated with higher CSF HIV-1 RNA and a lower plasma to CSF HIV-1 RNA ratio, suggesting a potential association with HIV-1 neuroinvasion.

Progress Note 2024: Curing HIV; Not in My Lifetime or Just Around the Corner?

Once a death sentence, HIV is now considered a manageable chronic disease due to the development of antiretroviral therapy (ART) regimens with minimal toxicity and a high barrier for genetic resistance. While highly effective in arresting AIDS progression and rendering the virus untransmissible in people living with HIV (PLWH) with undetectable viremia (U=U) [1, 2]), ART alone is incapable of eradicating the "reservoir" of resting, latently infected CD4+ T cells from which virus recrudesces upon treatment cessation. As of 2022 estimates, there are 39 million PLWH, of whom 86% are aware of their status and 76% are receiving ART [3]. As of 2017, ART-treated PLWH exhibit near normalized life expectancies without adjustment for socioeconomic differences [4]. Furthermore, there is a global deceleration in the rate of new infections [3] driven by expanded access to pre-exposure prophylaxis (PrEP), HIV testing in vulnerable populations, and by ART treatment [5]. Therefore, despite outstanding issues pertaining to cost and access in developing countries, there is strong enthusiasm that aggressive testing, treatment, and effective viral suppression may be able to halt the ongoing HIV epidemic (ie, UNAIDS' 95-95-95 targets) [6-8]; especially as evidenced by recent encouraging observations in Sydney [9]. Despite these promising efforts to limit further viral transmission, for PLWH, a "cure" remains elusive; whether it be to completely eradicate the viral reservoir (ie, cure) or to induce long-term viral remission in the absence of ART (ie, control; Figure 1). In a previous salon hosted by Pathogens and Immunity in 2016 [10], some researchers were optimistic that a cure was a feasible, scalable goal, albeit with no clear consensus on the best route. So, how are these cure strategies panning out? In this commentary, 8 years later, we will provide a brief overview on recent advances and failures towards identifying determinants of viral persistence and developing a scalable cure for HIV. Based on these observations, and as in the earlier salon, we have asked several prominent HIV cure researchers for their perspectives.

Molecular epidemiology to aid virtual elimination of HIV transmission in Australia

The Global UNAIDS 95/95/95 targets aim to increase the percentage of persons who know their HIV status, receive antiretroviral therapy, and have achieved viral suppression. Achieving these targets requires efforts to improve the public health response to increase access to care for those living with HIV, identify those yet undiagnosed with HIV early, and increase access to prevention for those most at risk of HIV acquisition. HIV infections in Australia are among the lowest globally having recorded significant declines in new diagnoses in the last decade. However, the HIV epidemic has changed with an increasing proportion of newly diagnosed infections among those born outside Australia observed in the last five years. Thus, the current prevention efforts are not enough to achieve the UNAIDS targets and virtual elimination across all population groups. We believe both are possible by including molecular epidemiology in the public health response. Molecular epidemiology methods have been crucial in the field of HIV prevention, particularly in demonstrating the efficacy of treatment as prevention. Cluster detection using molecular epidemiology can provide opportunities for the real-time detection of new outbreaks before they grow, and cluster detection programs are now part of the public health response in the USA and Canada. Here, we review what molecular epidemiology has taught us about HIV evolution and spread. We summarize how we can use this knowledge to improve public health measures by presenting case studies from the USA and Canada. We discuss the successes and challenges of current public health programs in Australia, and how we could use cluster detection as an add-on to identify gaps in current prevention measures easier and respond quicker to growing clusters. Lastly, we raise important ethical and legal challenges that need to be addressed when HIV genotypic data is used in combination with personal data.

Laboratory-based evaluation of the 4th-generation AlereTM HIV Combo rapid point-of-care test

BACKGROUND

Mozambique is a high-prevalence country for HIV and early detection of new HIV infections is crucial for control of the epidemic. We aimed to evaluate the accuracy of the 4th-generation rapid diagnostic test (RDT) AlereTM HIV Combo in detecting acute and seroconverted HIV-infection, among sexually-active women attending three clinical health centers in Maputo, Mozambique.

METHODS

Women aged 14-55 years (n = 920) seeking care at the Mavalane Health Area, Maputo (February 2018-January 2019) were included, and blood specimens sampled. Sociodemographic and sexual behavior data were collected. Point-of-care HIV testing was performed using Alere DetermineTM HIV-1/2 and Uni-GoldTM HIV-1/2. All samples were also tested using Enzygnost® HIV Integral 4 and Innotest® HIV Antigen mAb in laboratory. The 4th-generation RDT AlereTM HIV Combo was evaluated on serum samples in the laboratory. Finally, Innotest® HIV Antigen mAb, Enzygnost® HIV Integral 4 (Ag/Ab), and HIV RNA quantification acted as gold standard assays in the evaluation of AlereTM HIV Combo test for HIV antigen detection (in clinical samples and in three HIV-1 seroconversion panels).

RESULTS

The antibody component of the 4th generation AlereTM HIV Combo RDT demonstrated a sensitivity and specificity of 100% examining clinical samples. However, the test did not detect HIV p24 antigen in any clinical samples, while Innotest® HIV Antigen mAb, verified by Enzygnost® HIV Integral 4 (Ag/Ab) and/or HIV RNA quantification, detected HIV antigen in six clinical samples. Furthermore, the AlereTM HIV Combo RDT had a low sensitivity in the detection of HIV p24 antigen in seroconversion panels. The HIV prevalence among the examined women was 17.8%.

CONCLUSIONS

The 4th-generation RDT AlereTM HIV Combo showed similar sensitivity to the 3rd-generation RDTs to detect seroconverted HIV-infections. However, the sensitivity for detection of HIV p24 antigen and diagnosing acute HIV infections, before seroconversion, was low. There is an urgent need to develop and evaluate simple and affordable POC tests with high sensitivity and specificity for diagnosing individuals with acute HIV infection in resource-limited settings with high HIV prevalence.

A Case of Acute HIV-1 and Monkeypox Coinfection After Condomless Insertive Anal Sex in the Previous 69 Days - Beijing Municipality, China, August-October, 2023

What is already known about this topic?

The prevalence of monkeypox (mpox) infections is primarily observed among young men who engage in sexual activities with other men, and there is a possibility of sexual transmission. Co-occurring sexually transmitted infections have also been documented.

What is added by this report?

In this report, we present a case of a patient in China who was simultaneously diagnosed with mpox, and acute human immunodeficiency virus (HIV) infection. The patient exhibited symptoms of fever and widespread papules on the trunk, face, and genital area.

What are the implications for public health practice?

It is crucial for health agencies to prioritize HIV testing when mpox is suspected or diagnosed in individuals with recent engagement in high-risk sexual behavior.

Predictors of HIV rebound differ by timing of antiretroviral therapy initiation

BACKGROUNDIdentifying factors that predict the timing of HIV rebound after treatment interruption will be crucial for designing and evaluating interventions for HIV remission.METHODSWe performed a broad evaluation of viral and immune factors that predict viral rebound (AIDS Clinical Trials Group A5345). Participants initiated antiretroviral therapy (ART) during chronic (N = 33) or early (N = 12) HIV infection with ≥ 2 years of suppressive ART and restarted ART if they had 2 viral loads ≥ 1,000 copies/mL after treatment interruption.RESULTSCompared with chronic-treated participants, early-treated individuals had smaller and fewer transcriptionally active HIV reservoirs. A higher percentage of HIV Gag-specific CD8+ T cell cytotoxic response was associated with lower intact proviral DNA. Predictors of HIV rebound timing differed between early- versus chronic-treated participants, as the strongest reservoir predictor of time to HIV rebound was level of residual viremia in early-treated participants and intact DNA level in chronic-treated individuals. We also identified distinct sets of pre-treatment interruption viral, immune, and inflammatory markers that differentiated participants who had rapid versus slow rebound.CONCLUSIONThe results provide an in-depth overview of the complex interplay of viral, immunologic, and inflammatory predictors of viral rebound and demonstrate that the timing of ART initiation modifies the features of rapid and slow viral rebound.TRIAL REGISTRATIONClinicalTrials.gov NCT03001128FUNDINGNIH National Institute of Allergy and Infectious Diseases, Merck.

Longitudinal patterns of inflammatory mediators after acute HIV infection correlate to intact and total reservoir

Background

Despite the beneficial effects of antiretroviral therapy (ART) initiation during acute HIV infection (AHI), residual immune activation remains a hallmark of treated HIV infection.

Methods

Plasma concentrations of 40 mediators were measured longitudinally in 39 early treated participants of a Belgian AHI cohort (HIV+) and in 21 HIV-negative controls (HIV-). We investigated the association of the inflammatory profile with clinical presentation, plasma viral load, immunological parameters, and in-depth characterization of the HIV reservoir.

Results

While levels of most soluble mediators normalized with suppressive ART, we demonstrated the persistence of a pro-inflammatory signature in early treated HIV+ participants in comparison to HIV- controls. Examination of these mediators demonstrated a correlation with their levels during AHI, which seemed to be viremia-driven, and suggested involvement of an activated myeloid compartment, IFN-γ-signaling, and inflammasome-related pathways. Interestingly, some of these pro-inflammatory mediators correlated with a larger reservoir size and slower reservoir decay. In contrast, we also identified soluble mediators which were associated with favorable effects on immunovirological outcomes and reservoir, both during and after AHI.

Conclusion

These data highlight how the persistent pro-inflammatory profile observed in early ART treated individuals is shaped during AHI and is intertwined with viral dynamics.

Inferring Viral Transmission Time from Phylogenies for Known Transmission Pairs

When the time of an HIV transmission event is unknown, methods to identify it from virus genetic data can reveal the circumstances that enable transmission. We developed a single-parameter Markov model to infer transmission time from an HIV phylogeny constructed of multiple virus sequences from people in a transmission pair. Our method finds the statistical support for transmission occurring in different possible time slices. We compared our time-slice model results to previously described methods: a tree-based logical transmission interval, a simple parsimony-like rules-based method, and a more complex coalescent model. Across simulations with multiple transmitted lineages, different transmission times relative to the source's infection, and different sampling times relative to transmission, we found that overall our time-slice model provided accurate and narrower estimates of the time of transmission. We also identified situations when transmission time or direction was difficult to estimate by any method, particularly when transmission occurred long after the source was infected and when sampling occurred long after transmission. Applying our model to real HIV transmission pairs showed some agreement with facts known from the case investigations. We also found, however, that uncertainty on the inferred transmission time was driven more by uncertainty from time calibration of the phylogeny than from the model inference itself. Encouragingly, comparable performance of the Markov time-slice model and the coalescent model-which make use of different information within a tree-suggests that a new method remains to be described that will make full use of the topology and node times for improved transmission time inference.

A potential transition from a concentrated to a generalized HIV epidemic: the case of Madagascar

BACKGROUND

HIV expansion is controlled by a range of interrelated factors, including the natural history of HIV infection and socio-economical and structural factors. However, how they dynamically interact in particular contexts to drive a transition from concentrated HIV epidemics in vulnerable groups to generalized epidemics is poorly understood. We aim to explore these mechanisms, using Madagascar as a case-study.

METHODS

We developed a compartmental dynamic model using available data from Madagascar, a country with a contrasting concentrated epidemic, to explore the interaction between these factors with special consideration of commercial and transactional sex as HIV-infection drivers.

RESULTS

The model predicts sigmoidal-like prevalence curves with turning points within years 2020-2022, and prevalence reaching stabilization by 2033 within 9 to 24% in the studied (10 out of 11) cities, similar to high-prevalence regions in Southern Africa. The late/slow introduction of HIV and  circumcision, a widespread traditional practice in Madagascar, could have slowed down HIV propagation, but, given the key interplay between risky behaviors associated to young women and acute infections prevalence, mediated by transactional sex, the protective effect of circumcision is currently insufficient to contain the expansion of the disease in Madagascar.

CONCLUSIONS

These results suggest that Madagascar may be experiencing a silent transition from a concentrated to a generalized HIV epidemic. This case-study model could help to understand how this HIV epidemic transition occurs.

Does the rapid initiation of antiretroviral therapy at HIV diagnosis impact virological response in a real-life setting? A single-centre experience in Northern Italy

Rapid initiation of antiretroviral therapy (ART) has been proven efficacious and safe, but more investigations are needed to define feasibility of rapid ART approach in real-life settings.We conducted a retrospective, observational study on newly HIVdiagnosed patients referred to our Infectious Diseases Department from September 1st, 2015, to July 31st, 2019. According to the timing of ART initiation, we distinguished 3 groups of patients (rapid, intermediate and late group) and represented the trend of virological response during a 400-days-period. The hazard ratios of each predictor on viral suppression were estimated through the Cox proportional hazard model.The median time from HIV diagnosis to the first medical referral was 15 days and the median time from the first care access to therapy start was 24 days. Among patients, 37.6% started ART within 7 days, 20.6% between 8 and 30 days, and 41.8% after 30 days. Longer time to ART start and higher baseline viral load were associated with a lower probability of viral suppression. After one year, all groups showed a high viral suppression rate (99%). In a high-income setting the rapid ART approach seems useful to accelerate viral suppression which is great over time regardless of ART initiation timing.