Genetic diversity from proviral DNA as a proxy for time since HIV-1 infection.

HIV-1 RNA genetic diversity predicts time since infection which is important for clinical care and research. It's unclear, however, whether proviral DNA genetic diversity sampled under suppressive antiretroviral therapy can be used for this purpose. We tested whether proviral genetic diversity from NGS sequences predicts time since infection and recency in 221 people with HIV-1 with known infection time. Proviral diversity was significantly associated with time since infection (p<5*10-07, R2 up to 25%) and predictive of treatment initiation during recent infection (AUC-ROC up to 0.85). This shows the utility of proviral genetic diversity as a proxy for time since infection.

Circulating HBV RNA and hepatitis B core-related antigen trajectories in persons with HIV/HBV coinfection and HBsAg loss on tenofovir therapy.

BACKGROUND: We evaluated long-term trajectories of circulating hepatitis B virus (HBV)-RNA and hepatitis B core-related antigen (HBcrAg) in persons with and without hepatitis B surface antigen (HBsAg) loss during tenofovir therapy in the Swiss HIV Cohort Study. METHODS: We included 29 persons with HIV (PWH) with HBsAg loss and 29 matched PWH without loss. We compared HBV-RNA and HBcrAg decline and assessed the cumulative proportions with undetectable HBV-RNA and HBcrAg levels during tenofovir therapy using Kaplan-Meier estimates. RESULTS: HBsAg loss occurred after a median of 4 years (IQR 1 - 8). All participants with HBsAg loss achieved suppressed HBV-DNA and undetectable HBV-RNA preceding undetectable qHBsAg levels, whereas 79% achieved negative HBcrAg. In comparison, 79% of the participants without HBsAg loss achieved undetectable HBV-RNA and 48% negative HBcrAg. After two years on tenofovir, an HBV RNA decline ≥1 log10 copies/ml had 100% sensitivity and 36.4% specificity for HBsAg loss, whereas an HBcrAg decline ≥1 log10 U/ml had 91.0% sensitivity and 64.5% specificity. CONCLUSIONS: HBV-RNA suppression preceded undetectable qHBsAg levels, and had high sensitivity but low specificity for HBsAg loss during tenofovir therapy in PWH. HBcrAg remained detectable in approximately 20% of persons with, and 50% of persons without HBsAg loss.

Deciphering Factors Linked With Reduced Severe Acute Respiratory Syndrome Coronavirus 2 Susceptibility in the Swiss HIV Cohort Study.

BACKGROUND: Factors influencing susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remain to be resolved. Using data from the Swiss HIV Cohort Study on 6270 people with human immunodeficiency virus (HIV) and serologic assessment for SARS-CoV-2 and circulating human coronavirus (HCoV) antibodies, we investigated the association of HIV-related and general parameters with SARS-CoV-2 infection. METHODS: We analyzed SARS-CoV-2 polymerase chain reaction test results, COVID-19-related hospitalizations, and deaths reported to the Swiss HIV Cohort Study between 1 January 2020 and 31 December 2021. Antibodies to SARS-CoV-2 and HCoVs were determined in prepandemic (2019) and pandemic (2020) biobanked plasma samples and compared with findings in HIV-negative individuals. We applied logistic regression, conditional logistic regression, and bayesian multivariate regression to identify determinants of SARS-CoV-2 infection and antibody responses to SARS-CoV-2 in people with HIV. RESULTS: No HIV-1-related factors were associated with SARS-CoV-2 acquisition. High prepandemic HCoV antibodies were associated with a lower risk of subsequent SARS-CoV-2 infection and with higher SARS-CoV-2 antibody responses on infection. We observed a robust protective effect of smoking on SARS-CoV-2 infection risk (adjusted odds ratio, 0.46 [95% confidence interval, .38-.56]; P < .001), which occurred even in previous smokers and was highest for heavy smokers. CONCLUSIONS: Our findings of 2 independent protective factors, smoking and HCoV antibodies, both affecting the respiratory environment, underscore the importance of the local immune milieu in regulating susceptibility to SARS-CoV-2.

Antiretroviral Drug Exposure and Response in Obese and Morbidly Obese People With Human Immunodeficiency Virus (HIV): A Study Combining Modelling and Swiss HIV Cohort Data.

BACKGROUND: Obesity is increasingly prevalent among people with HIV (PWH) and can possibly result in suboptimal antiretroviral drug (ARV) exposure and response. However, this has not been thoroughly evaluated given that obese PWH are underrepresented in clinical trials. We performed virtual trials using physiologically based pharmacokinetic (PBPK) modelling combined with observed clinical data to provide ARV dosing guidance in obese individuals. METHODS: Each trial included a cohort of virtual adults with a body mass index (BMI) between 18.5 and 60 kg/m2. Therapeutic drug-monitoring data from the Swiss HIV Cohort Study (SHCS) were used to verify the predictive performance of the model. Subsequently, the model was applied to predict the pharmacokinetics of ARVs for different obesity classes. The association between ARV plasma concentrations and virological response was investigated in obese and nonobese individuals. RESULTS: The PBPK model predicted an average reduction in ARV exposure of ∼20% and trough concentrations of ∼6% in obese (BMI ≥30 kg/m2) compared with nonobese (BMI: 18.5-25 kg/m2) individuals, consistent with observed clinical data. Etravirine and rilpivirine were the most impacted, especially in individuals with BMI >40 kg/m2 whose trough concentrations were below the clinical target threshold. Obese PWH in the SHCS did not have a higher rate of unsuppressed viral load than nonobese PWH. CONCLUSIONS: The concentrations of ARVs are modestly reduced in obese individuals, with no negative impact on the virological response. Our data provide reassurance that standard doses of ARVs are suitable in obese PWH, including those who gained substantial weight with some of the first-line ARVs.

Cardiovascular Disease Risk Factor Control in People With and Without HIV.

BACKGROUND: Management of hypertension, dyslipidemia, diabetes and other modifiable factors may mitigate the cardiovascular disease (CVD) risk in people with human immunodeficiency virus (HIV, PWH) compared with people without HIV (PWoH). METHODS: This was a retrospective cohort study of 8285 PWH and 170 517 PWoH from an integrated health system. Risk factor control was measured using a novel disease management index (DMI) accounting for amount/duration above treatment goals (0% to 100% [perfect control]), including 2 DMIs for hypertension (diastolic and systolic blood pressure), 3 for dyslipidemia (low-density lipoprotein, total cholesterol, triglycerides), and 1 for diabetes (HbA1c). CVD risk by HIV status was evaluated overall and in subgroups defined by DMIs, smoking, alcohol use, and overweight/obesity in adjusted Cox proportional hazards models. RESULTS: PWH and PWoH had similar DMIs (80%-100%) except for triglycerides (worse for PWH) and HbA1c (better for PWH). In adjusted models, PWH had an elevated risk of CVD compared with PWoH (hazard ratio [HR], 1.18; 95% confidence interval [CI], 1.07-1.31). This association was attenuated in subgroups with controlled dyslipidemia and diabetes but remained elevated for PWH with controlled hypertension or higher total cholesterol. The strongest HIV status association with CVD was seen in the subgroup with frequent unhealthy alcohol use (HR, 2.13; 95% CI, 1.04-4.34). CONCLUSIONS: Control of dyslipidemia and diabetes, but not hypertension, attenuated the HIV status association with CVD. The strong association of HIV and CVD with frequent unhealthy alcohol use suggests enhanced screening and treatment of alcohol problems in PWH is warranted.

Weight, anthropometric and metabolic changes after discontinuing antiretroviral therapy containing tenofovir alafenamide (TAF) in people with HIV.

BACKGROUND: Antiretroviral therapy (ART)-related weight gain is of particular concern in people with HIV (PWH). While weight gain was observed among PWH receiving tenofovir alafenamide (TAF), little is known about the potential reversibility after TAF discontinuation. We evaluated weight and metabolic changes 12 months after TAF discontinuation in the Swiss HIV Cohort Study. METHODS: We included participants who received at least six months of TAF-containing ART between January 2016 and March 2023. Using multivariable mixed-effect models, changes in weight and lipid levels were compared between individuals who continued TAF and those who switched to one of the following TAF-free regimens: TDF-based ART, dolutegravir/lamivudine (DTG/3TC), or long-acting cabotegravir/rilpivirine (CAB/RPV). RESULTS: Of 6555 participants (median age 54 years, 24.3% female, 13% Black), 5485 (83.7%) continued and 1070 (16.3%) stopped TAF. Overall, discontinuing TAF was associated with an adjusted mean weight change of -0.54 kg (95% CI -0.98 to -0.11) after 12 months. In stratified analyses, switching from TAF to TDF led to an adjusted mean weight decrease of -1.84 kg (CI -2.72 to -0.97), and to a decrease in mean total cholesterol (-0.44 mmol/L) and triglycerides (-0.38 mmol/L) after 12 months. Switching from TAF-based ART to DTG/3TC (-0.17 kg, CI -0.82 to 0.48) or long-acting CAB/RPV (-0.64 kg, CI -2.16 to 0.89) did not lead to reductions in weight. CONCLUSIONS: Replacing TAF with TDF in PWH led to a decrease in body weight and an improved lipid profile within one year. Weight changes were not observed among individuals who switched to DTG/3TC or long-acting CAB/RPV.

Active PD-L1 incorporation within HIV virions functionally impairs T follicular helper cells.

The limited development of broadly neutralizing antibodies (BnAbs) during HIV infection is classically attributed to an inadequate B-cell help brought by functionally impaired T follicular helper (Tfh) cells. However, the determinants of Tfh-cell functional impairment and the signals contributing to this condition remain elusive. In the present study, we showed that PD-L1 is incorporated within HIV virions through an active mechanism involving p17 HIV matrix protein. We subsequently showed that in vitro produced PD-L1high but not PD-L1low HIV virions, significantly reduced Tfh-cell proliferation and IL-21 production, ultimately leading to a decreased of IgG1 secretion from GC B cells. Interestingly, Tfh-cell functions were fully restored in presence of anti-PD-L1/2 blocking mAbs treatment, demonstrating that the incorporated PD-L1 proteins were functionally active. Taken together, the present study unveils an immunovirological mechanism by which HIV specifically exploits the regulatory potential of PD-L1 to suppress the immune system during the course of HIV infection.

Long-term quantitative hepatitis B surface antigen (HBsAg) trajectories in persons with and without HBsAg loss on tenofovir-containing antiretroviral therapy.

OBJECTIVES: Improving the understanding of the patterns of quantitative hepatitis B surface antigen (qHBsAg) trajectories associated with HBsAg loss is important in light of novel anti-hepatitis B virus agents being developed. We evaluated long-term qHBsAg trajectories in persons with HIV and HBV during tenofovir-containing antiretroviral therapy in the Swiss HIV Cohort Study. METHODS: We included 29 participants with and 29 without HBsAg loss, defined as qHBsAg <0.05 IU/mL. We assessed qHBsAg decline during therapy in both groups and used agglomerative hierarchical clustering to identify different qHBsAg trajectory profiles in persons with HBsAg loss. RESULTS: The median follow-up time was 11.9 years (IQR 8.4-14.1), and the median time to HBsAg loss was 48 months (IQR 12-96). Among participants with HBsAg loss, 79% had a qHBsAg decline ≥1 log10 IU/mL 2 years after starting tenofovir. The trajectories in qHBsAg levels during tenofovir therapy were heterogeneous, characterized by five distinct profiles. Among participants without HBsAg loss, only 7% had a qHBsAg decline ≥1 log10 IU/ml after 2 years. CONCLUSIONS: Most persons with HIV who experienced HBsAg loss had an early decline in qHBsAg levels, with diverse trajectories during long-term tenofovir therapy. In persons without HBsAg loss, qHBsAg levels remained remarkably stable over time.

Impact of hormonal therapy on HIV-1 immune markers in cis women and gender minorities.

BACKGROUND: Although sex hormones are recognized to induce immune variations, the effect of hormonal therapy use on immunity is only poorly understood. Here, we quantified how hormonal therapy use affects HIV-1 immune markers in cis women (CW) and trans women and non-binary people (TNBP) with HIV. METHODS: We considered CD4, CD8 and lymphocyte measurements from cis men (CM), CW and TNBP in the Swiss HIV Cohort Study. We modelled HIV-1 markers using linear mixed-effects models with an interaction between 'gender' (CW, TNBP) and 'hormonal therapy use' (yes/no). Models were adjusted on age, ethnicity, education level, time since start of antiretroviral therapy and use of intravenous drugs. We assessed the inflammatory effect of hormonal therapy use in 31 TNBP using serum proteomics measurements of 92 inflammation markers. RESULTS: We included 54 083 measurements from 3092 CW and 83 TNBP, and 147 230 measurements from 8611 CM. Hormonal therapy use increased CD4 count and CD4:CD8 ratio in TNBP more than in CW (pinteraction = 0.02 and 0.007, respectively). TNBP with hormonal therapy use had significantly higher CD4 counts [median = 772 cells/µL, interquartile range (IQR): 520-1006] than without (617 cells/µL, 426-892). This was similar to the effect of CW versus CM on CD4 T cells. Hormonal therapy use did not affect serum protein concentrations in TNBP. CONCLUSION: This study highlights the potential role of hormonal therapy use in modulating the immune system among other biological and social factors, especially in TNBP with HIV.

Long-term trends in hepatitis C prevalence, treatment uptake and liver-related events in the Swiss HIV Cohort Study.

BACKGROUND AND AIMS: Treatment for chronic hepatitis C virus (HCV) infections changed dramatically in the last decade. We assessed changes in the prevalence of replicating HCV infection, treatment uptake and liver-related morbidity and mortality in persons with HIV (PWH) and hepatitis C in the Swiss HIV cohort study. METHODS: We included all cohort participants between 2002 and 2021. We assessed yearly prevalence of replicating HCV infection, overall and liver-related mortality, as well as the yearly incidence of liver-related events in persons with at least one documented positive HCV-RNA. RESULTS: Of 14 652 participants under follow-up, 2294 had at least one positive HCV-RNA measurement. Of those, 1316 (57%) ever received an HCV treatment. Treatment uptake increased from 8.1% in 2002 to a maximum of 32.6% in 2016. Overall, prevalence of replicating HCV infection declined from 16.5% in 2004 to 1.3% in 2021. HCV prevalence declined from 63.2% to 7.1% in persons who inject drugs, and from 4.1% to 0.6% in men who have sex with men. Among the 2294 persons with replicating HCV infection, overall mortality declined from a maximum of 3.3 per 100 patient-years (PY) to 1.1 per 100 PY, and incidence of liver-related events decreased from 1.4/100 PY to 0.2/100 PY. CONCLUSIONS: The introduction of DAA therapy was associated with a more than 10-fold reduction in prevalence of replicating HCV infection in PWH, approaching the estimates in the general population. Overall mortality and liver-related events declined substantially in persons living with HIV and hepatitis C.

Population pharmacokinetic analysis of doravirine in real-world people with HIV.

AIMS: The pharmacokinetics of doravirine has been studied in clinical trials but not in real-world settings. Our study aims to characterize and identify factors influencing doravirine (a CYP3A4 substrate) pharmacokinetics in real-world people with HIV (PWH). METHODS: A total of 174 doravirine concentrations measured in 146 PWH followed up in the therapeutic drug monitoring (TDM) program at the University Hospital of Lausanne (Switzerland) between 2019 and 2023 were included in the analysis. Demographic data, clinical information and comedications were recorded during the routine SHCS visits (every 3-6 months). Population pharmacokinetic analysis and Monte Carlo simulations to investigate the clinical significance of the covariates retained in the final model were performed using NONMEM. RESULTS: A one-compartment model with first-order absorption and linear elimination best described doravirine pharmacokinetics. Potent CYP3A4 inhibitors and, to a lesser extent age, were the only tested covariates to significantly impact doravirine clearance (CL). Potent CYP3A4 inhibitors reduced CL by 50%, and a 30% decrease in CL was observed in an 80-year-old compared with a 55-year-old PWH. The effect of potent CYP3A4 inhibitors was prominent, explaining 59% of between-subject variability in CL. Model-based simulations predicted 2.8-fold and 1.6-fold increases in median steady-state trough and maximum doravirine concentrations, respectively, when a potent CYP3A4 inhibitor was co-administered. CONCLUSIONS: Our findings show that potent CYP3A4 inhibitors and age influence doravirine pharmacokinetics. However, given the good tolerability of doravirine, dosing adjustment of doravirine is probably not mandatory in those situations. TDM remains useful essentially in specific clinical situations, such as hepatic impairment, suspected nonadherence or pregnancy.

Tracing HIV-1 strains that imprint broadly neutralizing antibody responses.

Understanding the determinants of broadly neutralizing antibody (bNAb) evolution is crucial for the development of bNAb-based HIV vaccines1. Despite emerging information on cofactors that promote bNAb evolution in natural HIV-1 infections, in which the induction of bNAbs is genuinely rare2, information on the impact of the infecting virus strain on determining the breadth and specificity of the antibody responses to HIV-1 is lacking. Here we analyse the influence of viral antigens in shaping antibody responses in humans. We call the ability of a virus strain to induce similar antibody responses across different hosts its antibody-imprinting capacity, which from an evolutionary biology perspective corresponds to the viral heritability of the antibody responses. Analysis of 53 measured parameters of HIV-1-binding and neutralizing antibody responses in a cohort of 303 HIV-1 transmission pairs (individuals who harboured highly related HIV-1 strains and were putative direct transmission partners or members of an HIV-1 transmission chain) revealed that the effect of the infecting virus on the outcome of the bNAb response is moderate in magnitude but highly significant. We introduce the concept of bNAb-imprinting viruses and provide evidence for the existence of such viruses in a systematic screening of our cohort. The bNAb-imprinting capacity can be substantial, as indicated by a transmission pair with highly similar HIV-1 antibody responses and strong bNAb activity. Identification of viruses that have bNAb-imprinting capacities and their characterization may thus provide the potential to develop lead immunogens.

Quantifying and Predicting Ongoing Human Immunodeficiency Virus Type 1 Transmission Dynamics in Switzerland Using a Distance-Based Clustering Approach.

BACKGROUND: Despite effective prevention approaches, ongoing human immunodeficiency virus 1 (HIV-1) transmission remains a public health concern indicating a need for identifying its drivers. METHODS: We combined a network-based clustering method using evolutionary distances between viral sequences with statistical learning approaches to investigate the dynamics of HIV transmission in the Swiss HIV Cohort Study and to predict the drivers of ongoing transmission. RESULTS: We found that only a minority of clusters and patients acquired links to new infections between 2007 and 2020. While the growth of clusters and the probability of individual patients acquiring new links in the transmission network was associated with epidemiological, behavioral, and virological predictors, the strength of these associations decreased substantially when adjusting for network characteristics. Thus, these network characteristics can capture major heterogeneities beyond classical epidemiological parameters. When modeling the probability of a newly diagnosed patient being linked with future infections, we found that the best predictive performance (median area under the curve receiver operating characteristic AUCROC = 0.77) was achieved by models including characteristics of the network as predictors and that models excluding them performed substantially worse (median AUCROC = 0.54). CONCLUSIONS: These results highlight the utility of molecular epidemiology-based network approaches for analyzing and predicting ongoing HIV transmission dynamics. This approach may serve for real-time prospective assessment of HIV transmission.

[HIV pre-exposure prophylaxis: physicians are not prepared]. / Prophylaxie pré-exposition au VIH : les médecins ne sont pas préparés.

HIV pre-exposure prophylaxis (PrEP) is an effective tool in HIV prevention but is rarely prescribed by primary care physicians. A survey conducted among 147 physicians to assess their knowledge and interest in prescribing PrEP shows that 97% stated they have already heard of PrEP, but their knowledge of its indications, dosage, price, and side-effects is often incomplete or incorrect. For 69% of them, the main obstacle to prescribing PrEP is the lack of training on the subject. However, 70% of physicians express interest in receiving training to confidently prescribe PrEP to their patients. To address this demand, the clinical recommendations of the SwissPrEPared program are summarized.

La prophylaxie pré-exposition au VIH (PrEP) est un outil efficace dans la prévention du VIH mais rarement prescrite par les médecins de premier recours. Un sondage mené auprès de 147 médecins pour évaluer leurs connaissances et intérêt à prescrire la PrEP indique que 97 % déclarent avoir déjà entendu parler de la PrEP, mais aussi que leurs connaissances quant aux indications, posologie, prix et effets secondaires restent souvent lacunaires ou erronées. Pour 69 % des sondés, le principal obstacle à la prescription de la PrEP est le manque de formation sur le sujet. Cependant, 70 % des médecins se disent intéressés à être formés afin de prescrire la PrEP en toute confiance à leurs patients. Pour répondre à cette demande, les recommandations cliniques du programme SwissPrEPared sont résumées.

Leukocyte Count and Coronary Artery Disease Events in People With Human Immunodeficiency Virus: A Longitudinal Study.

BACKGROUND: People with human immunodeficiency virus (HIV; PWH) have increased cardiovascular risk. Higher leukocyte count has been associated with coronary artery disease (CAD) events in the general population. It is unknown whether the leukocyte-CAD association also applies to PWH. METHODS: In a case-control study nested within the Swiss HIV Cohort Study, we obtained uni- and multivariable odds ratios (OR) for CAD events, based on traditional and HIV-related CAD risk factors, leukocyte count, and confounders previously associated with leukocyte count. RESULTS: We included 536 cases with a first CAD event (2000-2021; median age, 56 years; 87% male; 84% with suppressed HIV RNA) and 1464 event-free controls. Cases had higher latest leukocyte count before CAD event than controls (median [interquartile range], 6495 [5300-7995] vs 5900 [4910-7200]; P < .01), but leukocytosis (>11 000/µL) was uncommon (4.3% vs 2.1%; P = .01). In the highest versus lowest leukocyte quintile at latest time point before CAD event, participants had univariable CAD-OR = 2.27 (95% confidence interval, 1.63-3.15) and multivariable adjusted CAD-OR = 1.59 (1.09-2.30). For comparison, univariable CAD-OR for dyslipidemia, diabetes, and recent abacavir exposure were 1.58 (1.29-1.93), 2.19 (1.59-3.03), and 1.73 (1.37-2.17), respectively. Smoking and, to a lesser degree, alcohol and ethnicity attenuated the leukocyte-CAD association. Leukocytes measured up to 8 years before the event were significantly associated with CAD events. CONCLUSIONS: PWH in Switzerland with higher leukocyte counts have an independently increased risk of CAD events, to a degree similar to traditional and HIV-related risk factors.

Understanding the Decline of Incident, Active Tuberculosis in People With Human Immunodeficiency Virus in Switzerland.

BACKGROUND: People with human immunodeficiency virus type 1 (HIV-1) (PWH) are frequently coinfected with Mycobacterium tuberculosis (MTB) and at risk for progressing from asymptomatic latent TB infection (LTBI) to active tuberculosis (TB). LTBI testing and preventive treatment (TB specific prevention) are recommended, but its efficacy in low transmission settings is unclear. METHODS: We included PWH enrolled from 1988 to 2022 in the Swiss HIV Cohort study (SHCS). The outcome, incident TB, was defined as TB ≥6 months after SHCS inclusion. We assessed its risk factors using a time-updated hazard regression, modeled the potential impact of modifiable factors on TB incidence, performed mediation analysis to assess underlying causes of time trends, and evaluated preventive measures. RESULTS: In 21 528 PWH, LTBI prevalence declined from 15.1% in 2001% to 4.6% in 2021. Incident TB declined from 90.8 cases/1000 person-years in 1989 to 0.1 in 2021. A positive LTBI test showed a higher risk for incident TB (hazard ratio [HR] 9.8, 5.8-16.5) but only 10.5% of PWH with incident TB were tested positive. Preventive treatment reduced the risk in LTBI test positive PWH for active TB (relative risk reduction, 28.1%, absolute risk reduction 0.9%). On population level, the increase of CD4 T-cells and reduction of HIV viral load were the main driver of TB decrease. CONCLUSIONS: TB specific prevention is effective in selected patient groups. On a population level, control of HIV-1 remains the most important factor for incident TB reduction. Accurate identification of PWH at highest risk for TB is an unmet clinical need.

A Phylogeny-aware GWAS Framework to Correct for Heritable Pathogen Effects on Infectious Disease Traits.

Infectious diseases are particularly challenging for genome-wide association studies (GWAS) because genetic effects from two organisms (pathogen and host) can influence a trait. Traditional GWAS assume individual samples are independent observations. However, pathogen effects on a trait can be heritable from donor to recipient in transmission chains. Thus, residuals in GWAS association tests for host genetic effects may not be independent due to shared pathogen ancestry. We propose a new method to estimate and remove heritable pathogen effects on a trait based on the pathogen phylogeny prior to host GWAS, thus restoring independence of samples. In simulations, we show this additional step can increase GWAS power to detect truly associated host variants when pathogen effects are highly heritable, with strong phylogenetic correlations. We applied our framework to data from two different host-pathogen systems, HIV in humans and X. arboricola in A. thaliana. In both systems, the heritability and thus phylogenetic correlations turn out to be low enough such that qualitative results of GWAS do not change when accounting for the pathogen shared ancestry through a correction step. This means that previous GWAS results applied to these two systems should not be biased due to shared pathogen ancestry. In summary, our framework provides additional information on the evolutionary dynamics of traits in pathogen populations and may improve GWAS if pathogen effects are highly phylogenetically correlated amongst individuals in a cohort.

Population pharmacokinetic modelling to characterize the effect of chronic kidney disease on tenofovir exposure after tenofovir alafenamide administration.

BACKGROUND: Tenofovir alafenamide is gradually replacing tenofovir disoproxil fumarate, both prodrugs of tenofovir, in HIV prevention and treatment. There is thus an interest in describing tenofovir pharmacokinetics (PK) and its variability in people living with HIV (PLWH) under tenofovir alafenamide in a real-life setting. OBJECTIVES: To characterize the usual range of tenofovir exposure in PLWH receiving tenofovir alafenamide, while assessing the impact of chronic kidney disease (CKD). METHODS: We conducted a population PK analysis (NONMEM®) on 877 tenofovir and 100 tenofovir alafenamide concentrations measured in 569 PLWH. Model-based simulations allowed prediction of tenofovir trough concentrations (Cmin) in patients having various levels of renal function. RESULTS: Tenofovir PK was best described using a one-compartment model with linear absorption and elimination. Creatinine clearance (CLCR, estimated according to Cockcroft and Gault), age, ethnicity and potent P-glycoprotein inhibitors were statistically significantly associated with tenofovir clearance. However, only CLCR appeared clinically relevant. Model-based simulations revealed 294% and 515% increases of median tenofovir Cmin in patients with CLCR of 15-29 mL/min (CKD stage 3), and less than 15 mL/min (stage 4), respectively, compared with normal renal function (CLCR = 90-149 mL/min). Conversely, patients with augmented renal function (CLCR > 149 mL/min) had a 36% decrease of median tenofovir Cmin. CONCLUSIONS: Kidney function markedly affects circulating tenofovir exposure after tenofovir alafenamide administration in PLWH. However, considering its rapid uptake into target cells, we suggest only a cautious increase of tenofovir alafenamide dosage intervals to 2 or 3 days only in case of moderate or severe CKD, respectively.

Prevalence of HIV-1 drug resistance mutations in proviral DNA in the Swiss HIV Cohort Study, a retrospective study from 1995 to 2018.

BACKGROUND: Genotypic resistance testing (GRT) is routinely performed upon diagnosis of HIV-1 infection or during virological failure using plasma viral RNA. An alternative source for GRT could be cellular HIV-1 DNA. OBJECTIVES: A substantial number of participants in the Swiss HIV Cohort Study (SHCS) never received GRT. We applied a method that enables access to the near full-length proviral HIV-1 genome without requiring detectable viraemia. METHODS: Nine hundred and sixty-two PBMC specimens were received. Our two-step nested PCR protocol was applied to generate two overlapping long-range amplicons of the HIV-1 genome, sequenced by next-generation sequencing (NGS) and analysed by MinVar, a pipeline to detect drug resistance mutations (DRMs). RESULTS: Six hundred and eighty-one (70.8%) of the samples were successfully amplified, sequenced and analysed by MinVar. Only partial information of the pol gene was contained in 82/681 (12%), probably due to naturally occurring deletions in the proviral sequence. All common HIV-1 subtypes were successfully sequenced. We detected at least one major DRM at high frequency (≥15%) in 331/599 (55.3%) individuals. Excluding APOBEC-signature (G-to-A mutation) DRMs, 145/599 (24.2%) individuals carried at least one major DRM. RT-inhibitor DRMs were most prevalent. The experienced time on ART was significantly longer in DRM carriers (P = 0.001) independent of inclusion or exclusion of APOBEC-signature DRMs. CONCLUSIONS: We successfully applied a reliable and efficient method to analyse near full-length HIV-1 proviral DNA and investigated DRMs in individuals with undetectable or low viraemia. Additionally, our data underscore the need for new computational tools to exclude APOBEC-related hypermutated NGS sequence reads for reporting DRMs.

Frequency matters: comparison of drug resistance mutation detection by Sanger and next-generation sequencing in HIV-1.

BACKGROUND: Next-generation sequencing (NGS) is gradually replacing Sanger sequencing (SS) as the primary method for HIV genotypic resistance testing. However, there are limited systematic data on comparability of these methods in a clinical setting for the presence of low-abundance drug resistance mutations (DRMs) and their dependency on the variant-calling thresholds. METHODS: To compare the HIV-DRMs detected by SS and NGS, we included participants enrolled in the Swiss HIV Cohort Study (SHCS) with SS and NGS sequences available with sample collection dates ≤7 days apart. We tested for the presence of HIV-DRMs and compared the agreement between SS and NGS at different variant-calling thresholds. RESULTS: We included 594 pairs of SS and NGS from 527 SHCS participants. Males accounted for 80.5% of the participants, 76.3% were ART naive at sample collection and 78.1% of the sequences were subtype B. Overall, we observed a good agreement (Cohen's kappa >0.80) for HIV-DRMs for variant-calling thresholds ≥5%. We observed an increase in low-abundance HIV-DRMs detected at lower thresholds [28/417 (6.7%) at 10%-25% to 293/812 (36.1%) at 1%-2% threshold]. However, such low-abundance HIV-DRMs were overrepresented in ART-naive participants and were in most cases not detected in previously sampled sequences suggesting high sequencing error for thresholds <3%. CONCLUSIONS: We found high concordance between SS and NGS but also a substantial number of low-abundance HIV-DRMs detected only by NGS at lower variant-calling thresholds. Our findings suggest that a substantial fraction of the low-abundance HIV-DRMs detected at thresholds <3% may represent sequencing errors and hence should not be overinterpreted in clinical practice.