Evaluation of an alternative HIV diagnostic algorithm using specimens from seroconversion panels and persons with established HIV infections

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.

Incidence and Risks of HIV Infection, Medication Options, and Adverse Effects in Accidental Needle Stick Injuries: A Narrative Review

Accidental needle sticks can lead to infections, including HIV. As scientists have learned more about HIV and its replicative physiology, identification of target sites and novel medications have been developed. HIV is spread throughout the population through contact with blood, semen, and rectal or vaginal secretions of infected individuals. Therefore, it is important in general for healthcare workers to be aware of its transmission modes and ways to minimize exposure. In this regard, even with hospitals providing education, training, and safety protocols, there is a continued infection spread with HIV, especially by accidental needle sticks. There is also a wide variety of testing that can be used for HIV utilizing different methodologies, allowing for improved measurement of infection status. Any person with HIV should be tested to clarify infection status and be educated to minimize future virus spread. The current CDC recommendations for HIV infection treatment are antiretroviral therapies, such as an HIV postexposure prophylaxis regimen, which consists of a cocktail of antiretrovirals and postexposure prophylaxis immediately for occupational exposures, such as accidental needlestick exposure from an HIV infected patient. To decrease accidental HIV stick injuries, there are safety precautions in place, that if followed, would help reduce this incidence. HIV accidental needle stick injuries still happen in the hospital workplace, but with proper education and treatment, if exposed, there is hope to minimize the effects.

Utility of the Signal-to-Cutoff Ratio and Antigen Index from Fourth- and Fifth-Generation HIV-1/HIV-2 Antigen/Antibody Assays for the Diagnosis of Acute HIV Infection: Applicability for Real-Time Use for Immediate Initiation of Antiretroviral Therapy

Identification of individuals with acute HIV infection (AHI) and rapid initiation of antiretroviral therapy (ART) are priorities for HIV elimination efforts. Fourth- and fifth-generation HIV-1/HIV-2 antigen (Ag)/antibody (Ab) combination assays can quickly identify patients with AHI, but false-positive results can occur. Confirmatory nucleic acid amplification testing (NAAT) may not be rapidly available. We reviewed the data for 127 patients with positive fourth-generation ARCHITECT and fifth-generation Bio-Plex immunoassay results who had negative or indeterminate confirmatory Ab testing results, which yielded 38 patients with confirmed AHI and 89 patients with false-positive results. The receiver operating characteristic (ROC) curves showed excellent discriminatory power, with an area under the curve (AUC) for the signal-to-cutoff (S/CO) ratio of 0.970 (95% confidence interval [CI], 0.935 to 1.00) and an AUC for the Ag index (AI) of 0.968 (95% CI, 0.904 to 1.00). A threshold of 3.78 for the S/CO ratio would maximize the sensitivity (96.3%) and specificity (93.4%). The threshold for AI was 2.83 (sensitivity of 100% and specificity of 96.4%). The S/CO ratio was significantly correlated with the viral load (Spearman correlation coefficient, 0.486 [P = 0.014]), but the AI was not. The viral loads were all high, with a median of >2.8 million copies/mL. Two false-positive results with AI and S/CO ratio values markedly higher than the medians were observed, indicating that biological false-positive results can occur. Review of the S/CO ratio or AI may be used to improve the accuracy of AHI diagnosis prior to confirmatory NAAT results being available.

Vaccine-Induced Seroreactivity Impacts the Accuracy of HIV Testing Algorithms in Sub-Saharan Africa: An Exploratory Study

The detection of vaccine-induced HIV antibody responses by rapid diagnostic tests (RDTs) may confound the interpretation of HIV testing results. We assessed the impact of vaccine-induced seroreactivity (VISR) on the diagnosis of HIV in sub-Saharan Africa. Samples collected from healthy participants of HIVIS and TaMoVac HIV vaccine trials after the final vaccination were analyzed for VISR using HIV testing algorithms used in Mozambique and Tanzania that employ two sequential RDTs. The samples were also tested for VISR using Enzygnost HIV Integral 4 ELISA and HIV western blot assays. Antibody titers to subtype C gp140 were determined using an in-house enzyme-linked immunosorbent assay (ELISA). The frequency of VISR was 93.4% (128/137) by Enzygnost HIV Integral 4 ELISA, and 66.4% (91/137) by western blot assay (WHO interpretation). The proportion of vaccine recipients that would have been misdiagnosed as HIV-positive in Mozambique was half of that in Tanzania: 26.3% (36/137) and 54.0% (74/137), respectively, p < 0.0001. In conclusion, the HIV RDTs and algorithms assessed here will potentially misclassify a large proportion of the HIV vaccine recipients if no other test is used. Increased efforts are needed to develop differential serological or molecular tools for use at the point of care.

Streamlining Laboratory Tests for HIV Detection

HIV is a retrovirus that primarily infects CD4 presenting cells of the human immune system, such as macrophages and dendritic cells. People die of AIDS because the disease remains undetected for long periods of time. HIV diagnostic testing has come a long way since it was introduced in the early 1980s. Early diagnosis is key to successful treatment of HIV. Assay selection is based on initial screening results and clinical information provided by the physician, both of which are essential for the laboratory’s ability to make accurate diagnoses. Detecting HIV with high specificity and sensitivity in the early stages of infection requires simple, accurate and economical methods. In this chapter we have described the indications & criteria’s for HIV testing, HIV diagnosis by utilizing variety of immunological and molecular methods, like ELISA, rapid diagnostics, Western blotting, indirect immunoassays, and nucleic acid-based tests. Diagnostic laboratories must use testing algorithms to ensure the accuracy of results and the optimal use of lab resources. Participation in laboratory quality assurance programs are also essential to ensure that diagnostic laboratories provide accurate, timely and clinically relevant test results. HIV testing is the first step in maintaining a healthy life and preventing HIV transmission.

Reducing False-Positive Results With Fourth-Generation HIV Testing at a Veterans Affairs Medical Center

Background

In 2006, the Centers for Disease Control and Prevention issued guidelines advocating routine HIV screening for all patients. However, false-positive results are a potential patient care threat for low-risk populations even with accurate screening assays. A reduction in HIV false-positive screening results can potentially be seen by switching from the third-generation to a more sensitive and specific fourth-generation screening assay.

Methods

We studied the impact on the false-positive screening rate of a change to a fourth-generation assay at a regional US Department of Veteran Affairs Medical Center. HIV screening tests performed by the laboratory from March 1, 2016 to February 28, 2017, prior to implementation of the new assay were compared with fourth-generation HIV screening tests performed from March 1, 2017 to February 28, 2018.

Results

Of 7,516 third-generation HIV screening tests reviewed, 52 were reactive on the screening assay; 24 were true positives, 28 were false positives. The following year 7,802 fourth-generation HIV screening tests were performed and 23 were reactive on the screening assay; 16 were true positives and 7 were false positives. The positive predictive value for the third-generation test was 46% and 70% for the fourth-generation test.

Conclusions

There were fewer false-positive results with testing with the more specific fourth- vs third-generation assay (0.09% vs 0.37%, respectively), which was statistically significant (P = .002). This reduction in false-positive screening would reduce the laboratory workload and would save an estimated $3,875 yearly and reduce the adverse effects of false-positive screening results for patients.

HIV antiretroviral therapy and prevention use in US blood donors: a new blood safety concern

Antiretroviral therapy (ART) to treat and pre-exposure prophylaxis (PrEP) to prevent HIV infection are effective tools to help end the HIV epidemic. However, their use could affect HIV transfusion-transmission risk. Three different ART/PrEP prevalence analyses in blood donors were conducted. First, blood samples from HIV-positive and a comparison group of infection-nonreactive donors were tested under blind using liquid chromatography-tandem mass spectrometry for ART. Second, blood donor samples from infection-nonreactive, 18- to 45-year-old, male, first-time blood donors in 6 US locations were tested for emtricitabine and tenofovir. Third, in men who have sex with men (MSM) participating in the 2017 Centers for Disease Control and Prevention National HIV Behavioral Surveillance (NHBS) from 5 US cities, self-reported PrEP use proximate to donation was assessed. In blind testing, no ART was detected in 300 infection-nonreactive donor samples, but in 299 HIV confirmed-infected donor samples, 46 (15.4%; 95% confidence interval [CI], 11.5% to 20.0%) had evidence of ART. Of the 1494 samples tested from first-time male donors, 9 (0.6%; 95% CI, 0.03% to 1.1%) had tenofovir and emtricitabine. In the NHBS MSM survey, 27 of 591 respondents (4.8%; 95% CI, 3.2% to 6.9%) reported donating blood in 2016 or 2017 and PrEP use within the same time frame as blood donation. Persons who are HIV positive and taking ART and persons taking PrEP to prevent HIV infection are donating blood. Both situations could lead to increased risk of HIV transfusion transmission if blood screening assays are unable to detect HIV in donations from infected donors.

Performance evaluation of the MedMira reveal G4 LAB S/P and POC HIV antibody rapid screening tests using plasma and whole blood specimens

BACKGROUND

The Reveal G4 antibody rapid test is FDA-approved for HIV-1 detection using the versions LAB S/P and POC in CLIA-moderate complexity settings with serum/plasma and whole blood, respectively. The same Reveal tests are CE-marked for HIV-1 and HIV-2 detection in laboratory and point-of-care (POC) settings.

OBJECTIVE

We compared the performance of G4 LAB S/P with plasma and POC with whole blood (blood) for detecting early and established HIV-1/HIV-2 infections.

STUDY DESIGN

Matched well-characterized plasma and simulated blood were used to evaluate: sensitivity in 104 HIV-1 and 55 HIV-2 established infections, specificity in 49 HIV-negative, and reactivity in early HIV-1 infection in a performance panel (n=38) and 18 plasma panels from seroconverters (SCs, n=183). Median number of days after first RNA-positive was calculated for 13 SCs. Impact of viral suppression (VS) was evaluated in 3 SCs receiving early antiretroviral therapy (ART).

RESULTS

Sensitivity was 100 % for HIV-1 and 98.18 % for HIV-2, while specificity was 100 %. All 38 plasma and blood become reactive by Fiebig stage V. Of 18 SCs, 10 had similar reactivity in plasma/blood, 7 showed delayed reactivity in blood, and 1 was nonreactive in plasma/blood. The median days for a G4-reactive after first RNApositive was 13 for plasma and 14 for blood. Long-term VS had no impact on G4 reactivity.

CONCLUSIONS

Overall reactivity in early HIV-1 infections is delayed by one day in blood compared to plasma. If FDA-approved for POC settings, the G4 POC is a fast sensitive screening tool for HIV-1/HIV-2-specific IgG even during VS.

Estimated dates of detectable infection (EDDIs) as an improvement upon Fiebig staging for HIV infection dating

Accurate methods for determining the duration of HIV infection at the individual level are valuable in many settings, including many critical research studies and in clinical practice (especially for acute infection). Since first published in 2003, the ‘Fiebig staging system’ has been used as the primary way of classifying early HIV infection into five sequential stages based on HIV test result patterns in newly diagnosed individuals. However, Fiebig stages can only be assigned to individuals who produce both a negative and a positive test result on the same day, on specific pairs of tests of varying ‘sensitivity’. Further, in the past 16 years HIV-testing technology has evolved substantially, and three of the five key assays used to define Fiebig stages are no longer widely used. To address these limitations, we developed an improved and more general framework for estimating the duration of HIV infection by interpreting any combination of diagnostic test results, whether obtained on single or multiple days, into an estimated date of detectable infection, or EDDI. A key advantage of the EDDI method over Fiebig staging is that it allows for the generation of a point estimate, as well as an associated credibility interval for the date of first detectable infection, for any person who has at least one positive and one negative HIV test of any kind. The tests do not have to be run on the same day; they do not have to be run during the acute phase of infection and the method does not rely on any special pairing of tests to define ‘stages’ of infection. The size of the interval surrounding the EDDI (and therefore the precision of the estimate itself) depends largely on the length of time between negative and positive tests. The EDDI approach is also flexible, seamlessly incorporating any assay for which there is a reasonable diagnostic delay estimate. An open-source, free online tool includes a user-updatable curated database of published diagnostic delays. HIV diagnostics have evolved tremendously since that original publication more than 15 years ago, and it is time to similarly evolve the methods used to estimate timing of infection. The EDDI method is a flexible and rigorous way to estimate the timing of HIV infection in a continuously evolving diagnostic landscape.

Evaluation of the performance of the Cepheid Xpert HIV-1 Viral Load Assay for quantitative and diagnostic uses

BACKGROUND

Cepheid's Xpert HIV-1 Viral Load (Xpert VL), a simplified, automated, single-use quantitative assay used with the GeneXpert System, is not FDA approved.

OBJECTIVES

Using stored plasma, we conducted a study to assess the ability of Xpert VL to quantify viral load relative to the Roche COBAS AmpliPrep/COBAS TaqMan HIV-1 (Cobas VL) and to examine the use of the Xpert VL as a qualitative diagnostic test.

STUDY DESIGN

Following HIV-1 viral stock dilutions, we conducted a probit analysis to identify the concentration where 95 % of specimens had quantified VLs. We also examined Xpert and Cobas log VL correlation in linearity panels; compared the proportion of 220 seroconverter specimens with virus detected using McNemar's test; and tested specimens from persons with untreated, established HIV-1 infection (n=149) and uninfected persons (n=497). Furthermore, we examined Xpert VL as a qualitative test in seroconverter specimens with early (n=20) and later (n=68) acute infections.

RESULTS

At 1.80 log10 copies/mL, 95 % of specimens had quantifiable virus using Xpert VL. Xpert and Cobas VLs were highly correlated (R2=0.994). The proportion of seroconverter specimens with virus detected using Cobas and with Xpert VL was not statistically different (p=0.0578). Xpert VL detected 97.9 % of established infections, and specificity was 99.80 % (95 % CI 98.87%-99.99%). Xpert VL detected 90 % and 98.5 % of early and later acute infections, respectively.

CONCLUSIONS

If approved, Xpert VL could allow U.S. laboratories that cannot bring on large, complex testing platforms to conduct HIV monitoring. An approval for diagnostic use may provide timely identification of HIV infections.

Interpreting HIV diagnostic histories into infection time estimates: analytical framework and online tool

Background

It is frequently of epidemiological and/or clinical interest to estimate the date of HIV infection or time-since-infection of individuals. Yet, for over 15 years, the only widely-referenced infection dating algorithm that utilises diagnostic testing data to estimate time-since-infection has been the ‘Fiebig staging’ system. This defines a number of stages of early HIV infection through various standard combinations of contemporaneous discordant diagnostic results using tests of different sensitivity. To develop a new, more nuanced infection dating algorithm, we generalised the Fiebig approach to accommodate positive and negative diagnostic results generated on the same or different dates, and arbitrary current or future tests – as long as the test sensitivity is known. For this purpose, test sensitivity is the probability of a positive result as a function of time since infection.

Methods

The present work outlines the analytical framework for infection date estimation using subject-level diagnostic testing histories, and data on test sensitivity. We introduce a publicly-available online HIV infection dating tool that implements this estimation method, bringing together 1) curatorship of HIV test performance data, and 2) infection date estimation functionality, to calculate plausible intervals within which infection likely became detectable for each individual. The midpoints of these intervals are interpreted as infection time ‘point estimates’ and referred to as Estimated Dates of Detectable Infection (EDDIs). The tool is designed for easy bulk processing of information (as may be appropriate for research studies) but can also be used for individual patients (such as in clinical practice).

Results

In many settings, including most research studies, detailed diagnostic testing data are routinely recorded, and can provide reasonably precise estimates of the timing of HIV infection. We present a simple logic to the interpretation of diagnostic testing histories into infection time estimates, either as a point estimate (EDDI) or an interval (earliest plausible to latest plausible dates of detectable infection), along with a publicly-accessible online tool that supports wide application of this logic.

Conclusions

This tool, available at https://tools.incidence-estimation.org/idt/, is readily updatable as test technology evolves, given the simple architecture of the system and its nature as an open source project.

HIV Testing With and Without a Clinical Consultation Among Men Who Have Sex With Men: A Randomized Controlled Trial

BACKGROUND

Increasing the frequency of HIV testing among men who have sex with men (MSM) maximizes the preventive effect of antiretroviral therapy, by reducing time to diagnosis and treatment.

SETTING

Melbourne Sexual Health Centre, Australia.

METHODS

This randomized controlled trial evaluated whether access to testing, without seeing a clinician would increase testing frequency. MSM attending for HIV testing between July 2014 and April 2015 were randomized in 1:1 ratio to the intervention arm (access to HIV and syphilis testing at 300 pathology centers, without requiring consultations) or the control arm (consultation at every test), without blinding. The primary outcome was the incidence of HIV testing over 12 months.

RESULTS

Of 443 men referred, 422 were randomized, 3 HIV positives at baseline were excluded, and 419 were analyzed. Of 208 control, 202 (97.1%) and 200 (94.8%) of 211 intervention group members were followed to 12 months. The intervention group had 453 tests in 205.6 person-years, incidence rate was 2.2 (95% confidence interval [CI]: 2.0 to 2.4) tests per year. The control group had 432 tests during 204.0 person-years, incidence rate was 2.1 (95% CI: 1.9 to 2.3) tests per year, and incidence rate ratio was 1.04 (95% CI: 0.89 to 1.2; P = 0.63). The annual rate of consultations was as follows: intervention, 1.61 (95% CI: 1.44 to 1.79); controls, 2.12 (95% CI: 1.92 to 2.33); rate ratio, 0.76 (95% CI: 0.65 to 0.88; P = 0.0001). There was no difference in quality of life scores (P = 0.61).

CONCLUSIONS

MSM permitted HIV and syphilis testing outside of clinical consultations did not test more frequently than controls but had 24% fewer consultations, reducing service demand.

TRIAL REGISTRATION

ACTRN12614000760673.

Combining Viral Genetics and Statistical Modeling to Improve HIV-1 Time-of-infection Estimation towards Enhanced Vaccine Efficacy Assessment

Knowledge of the time of HIV-1 infection and the multiplicity of viruses that establish HIV-1 infection is crucial for the in-depth analysis of clinical prevention efficacy trial outcomes. Better estimation methods would improve the ability to characterize immunological and genetic sequence correlates of efficacy within preventive efficacy trials of HIV-1 vaccines and monoclonal antibodies. We developed new methods for infection timing and multiplicity estimation using maximum likelihood estimators that shift and scale (calibrate) estimates by fitting true infection times and founder virus multiplicities to a linear regression model with independent variables defined by data on HIV-1 sequences, viral load, diagnostics, and sequence alignment statistics. Using Poisson models of measured mutation counts and phylogenetic trees, we analyzed longitudinal HIV-1 sequence data together with diagnostic and viral load data from the RV217 and CAPRISA 002 acute HIV-1 infection cohort studies. We used leave-one-out cross validation to evaluate the prediction error of these calibrated estimators versus that of existing estimators and found that both infection time and founder multiplicity can be estimated with improved accuracy and precision by calibration. Calibration considerably improved all estimators of time since HIV-1 infection, in terms of reducing bias to near zero and reducing root mean squared error (RMSE) to 5-10 days for sequences collected 1-2 months after infection. The calibration of multiplicity assessments yielded strong improvements with accurate predictions (ROC-AUC above 0.85) in all cases. These results have not yet been validated on external data, and the best-fitting models are likely to be less robust than simpler models to variation in sequencing conditions. For all evaluated models, these results demonstrate the value of calibration for improved estimation of founder multiplicity and of time since HIV-1 infection.

HIV Diagnostics: Current Recommendations and Opportunities for Improvement

Profound changes in technology have revolutionized laboratory testing for human immunodeficiency virus (HIV) since the first laboratory enzyme immunoassays that detected only immunoglobulin G (IgG) antibodies. Instrumented fourth-generation random-access chemiluminescent assays are now recommended for initial screening because they become reactive in as little as 2 weeks after infection. Using HIV-1 RNA viral load assays after a reactive initial test could confirm infection and provide useful clinical information. Early initiation of antiretroviral therapy and use of preexposure prophylaxis can alter the evolution of biomarkers and assay reactivity, leading to ambiguous test results.

A generalizable method for estimating duration of HIV infections using clinical testing history and HIV test results

OBJECTIVE

To determine the precision of new and established methods for estimating duration of HIV infection.

DESIGN

A retrospective analysis of HIV testing results from serial samples in commercially available panels, taking advantage of extensive testing previously conducted on 53 seroconverters.

METHODS

We initially investigated four methods for estimating infection timing: method 1, 'Fiebig stages' based on test results from a single specimen; method 2, an updated '4th gen' method similar to Fiebig stages but using antigen/antibody tests in place of the p24 antigen test; method 3, modeling of 'viral ramp-up' dynamics using quantitative HIV-1 viral load data from antibody-negative specimens; and method 4, using detailed clinical testing history to define a plausible interval and best estimate of infection time. We then investigated a 'two-step method' using data from both methods 3 and 4, allowing for test results to have come from specimens collected on different days.

RESULTS

Fiebig and '4th gen' staging method estimates of time since detectable viremia had similar and modest correlation with observed data. Correlation of estimates from both new methods (3 and 4), and from a combination of these two ('two-step method') was markedly improved and variability significantly reduced when compared with Fiebig estimates on the same specimens.

CONCLUSION

The new 'two-step' method more accurately estimates timing of infection and is intended to be generalizable to more situations in clinical medicine, research, and surveillance than previous methods. An online tool is now available that enables researchers/clinicians to input data related to method 4, and generate estimated dates of detectable infection.

Development and validation of plasma miRNA biomarker signature panel for the detection of early HIV-1 infection

Background

Accurate laboratory diagnosis of HIV is essential to reduce the risk of HIV-positive individuals transmitting HIV-1 infection. The goal of this study was to identify and assess a panel of host derived plasma miRNAs that could to serve as a prognostic and predictive biomarker to detect early/acute HIV-1 infection.

Methods

A total of 372 microRNAs were analyzed in nine plasma samples from HIV-1 infected individuals in the early phase of infection and three healthy controls using the miRNA PCR-array. Seventeen microRNAs were selected and validated in 80 plasma samples from HIV-1 infected individuals in the early phase of infection (20 each of eclipse stage, RNA+ stage, Ag + stage, and Ag + Ab+ stage of HIV-1 patients) and 25 healthy controls. Using the validation study results a plasma miRNA panel was developed and evaluated to detect early/acute HIV-1 infection in 49 blinded samples.

Finding

We identified an miRNA panel (P_eHIV-1) containing four differentially expressed miRNAs (miR-16-5p, miR-20b-5p, miR-195-5p, and miR-223-3p) that could distinguish early HIV-1 infection from healthy controls with high AUC (1·000[1·00–1·00]), sensitivity (100%), and specificity (100%).We also found that miR-223-3p demonstrates 100% sensitivity and specificity (AUC 1·00[1·00–1·00]) and could distinguish eclipse stage of HIV-1 infection from healthy controls. To detect eclipse stage of HIV-1 infection we also developed a four-miRNA based (miR-16-5p, miR-206, let-7 g-3p, and miR-181c-3p) panel (P_E) with AUC 0·999 (0·995–1·000), 100% sensitivity and 95·8% specificity.

Interpretation

The miRNA panel, P_eHIV-1 is a potential biomarker for detecting early/acute stage of HIV-1infection and could help initiate early antiretroviral treatment, thus preventing the spread of HIV-1 infection.

Performance evaluation of the Bio-Rad Geenius HIV 1/2 supplemental assay

BACKGROUND

In the US, the HIV diagnostic algorithm for laboratory settings recommends the use of an HIV-1/HIV-2 differentiation supplemental assay after an initial reactive antigen/antibody (Ag/Ab) assay result. Since the discontinuation of the Multispot HIV-1/HIV-2 Rapid Test (MS), the Geenius HIV-1/2 Supplemental assay (Geenius) is the only FDA-approved supplemental differentiation test.

OBJECTIVE

We compared the performance of Geenius to MS and Western Blot (WB).

STUDY DESIGN

The relative seroconversion plasma reactivity of Geenius and MS was assessed using a 50% cumulative frequency analysis from 17 HIV-1 seroconverters. In addition, previously characterized plasma specimens, 186 HIV-1 positive, 100 HIV-2 positive, and 93 Ag/Ab-positive/HIV-1 RNA-negative, were tested with Geenius v1.1 software. McNemar's test was used for paired comparison analysis. A subset of 48 specimens were retested with the upgraded Geenius v1.3 software.

RESULTS

In HIV-1 seroconverters, the relative seroconversion reactivity was 2.5 and 2 days before the first positive HIV-1 WB for Geenius and MS, respectively. In HIV-1 positive samples, Geenius performed similarly to HIV-1 WB (p=0.1687) and MS (p=0.8312). In HIV-2 positive samples, Geenius underperformed compared to HIV-2 WB (p=0.0005) and MS (p=0.0012). When using the upgraded software among the HIV-1 positive and Ag/Ab-reactive/HIV-1 RNA-negative samples, gp140 reactivity decreased without affecting characterization of HIV-2 samples.

CONCLUSIONS

With HIV-1 samples, Geenius, WB and MS performance was similar as supplemental tests. The updated Geenius software reduced false gp140 reactivity, but had no impact on identifying true HIV-2 infections. Further evaluation will assess the impact of the Geenius software update on final diagnostic interpretations.

Evaluation of the vitros hiv combo 4th generation test for the identification of HIV infections

BACKGROUND

Simultaneous detection of HIV 1 and 2 antibodies and HIV-1 p-24 antigen in the 4th generation tests is particularly effective for the identification of early acute HIV infections while maintaining accurate detection of long-established infections.

OBJECTIVES

The aim of this study was to evaluate the new 4th generation VITROS HIV Combo test from Ortho-Clinical Diagnostics by comparing its results with those obtained using a 3rd generation HIV 1/2 antibody test (VITROS Anti HIV 1 + 2 from Ortho-Clinical Diagnostics) and a 4th generation test (LIAISON XL HIV Ab/Ag, DiaSorin) currently used in the Microbiology Unit of Legnano Hospital.

STUDY DESIGN

One thousand and three samples of the normal daily routine (Group 1) were analyzed simultaneously with the three systems. The concordant and discordant sample results were further tested using Western blot and HIV-RNA assay (Roche). One hundred samples (Group 2) of known HIV positive subjects (63 of subtype B, 37 subtype non-B, and 51 with positive viraemia) and 50 samples (Group 3) with indeterminate Western blot were also examined using the three systems. From Group 3, 24 samples were collected from patients diagnosed with acute infection.

RESULTS

The overall agreement between the three systems was 99.4% (99.5% in group 1, 100% in group 2 and 96.6% in group 3) with a coefficient Fleiss Kappa of 0.9814. Notably, the VITROS HIV Combo test was positive in all known HIV positive samples of group 2 without any statistically significant difference in the values of the sample/cut off ratios between the B and non-B subtypes and between the positive and negative viraemia samples in established infections. The VITROS HIV Combo test was also positive in all samples of patients with acute infection in group 3.

CONCLUSIONS

The VITROS HIV Combo test has shown comparable performance to the other two assays in use of 3rd and 4th generation tests and is able to correctly identify both acute and established HIV infections independently of viraemia and HIV subtype.

No Time to Delay! Fiebig Stages and Referral in Acute HIV infection: Seattle Primary Infection Program Experience

There has been increasing recognition of the importance of diagnosing individuals during the earliest stages of human immunodeficiency virus (HIV) infection. Sera from individuals referred to a primary HIV infection research program were screened using the IgG-sensitive Vironostika HIV-1 Microelisa System, IgG/IgM-sensitive GS HIV-1/HIV-2 Plus O antibody enzyme immunoassay (EIA), or Abbott ARCHITECT HIV antigen (Ag)/antibody (Ab) Combo assay and confirmed by the Bio-Rad Multispot and Western blot. A subset of participants was co-enrolled in a study designed to compare the ability of point-of-care tests to detect early infection. We calculated time within primary infection laboratory stages using actual observed transitions and with an expectation-maximization algorithm. Three hundred and sixty participants contributed data to this analysis. Of 123 persons referred with EIA-negative/RNA-positive test results (Fiebig stage I-II) or for concern for symptoms, 24 (20%) were still in stages I-II, and 99 (80%) were in stages III or later at their screening visit. Participants were estimated to spend a median of 13.5 days in stages I and II, 2.3 days in stage III, and 7.8 days in stage IV. OraQuick performed on oral fluids detected 53% of 17 participants in stage V. The durations of stages we observed are consistent with previous publications. Most persons referred for research no longer had acute infection at their first visit. Programs wishing to identify persons in the very earliest stages of infection need to expedite referrals or develop targeted screening programs.

Comparison of Detection Limits of Fourth- and Fifth-Generation Combination HIV Antigen-Antibody, p24 Antigen, and Viral Load Assays on Diverse HIV Isolates

Detection of acute HIV infection is critical for HIV public health and diagnostics. Clinical fourth-generation antigen (Ag)/antibody (Ab) combination (combo) and p24 Ag immunoassays have enhanced detection of acute infection compared to Ab-alone assays but require ongoing evaluation with currently circulating diverse subtypes. Genetically and geographically diverse HIV clinical isolates were used to assess clinical HIV diagnostic, blood screening, and next-generation assays. Three-hundred-member panels of 20 serially diluted well-characterized antibody-negative HIV isolates for which the researchers were blind to the results (blind panels) were distributed to manufacturers and end-user labs to assess the relative analytic sensitivity of currently approved and preapproved clinical HIV fourth-generation Ag/Ab combo or p24 Ag-alone immunoassays for the detection of diverse subtypes. The limits of detection (LODs) of virus were estimated for different subtypes relative to confirmed viral loads. Analysis of immunoassay sensitivity was benchmarked against confirmed viral load measurements on the blind panel. On the basis of the proportion of positive results on 300 observations, all Ag/Ab combo and standard sensitivity p24 Ag assays performed similarly and within half-log LODs, illustrating the similar breadth of reactivity and diagnostic utility. Ultrasensitive p24 Ag assays achieved dramatically increased sensitivities, while the rapid combo assays performed poorly. The similar performance of the different commercially available fourth-generation assays on diverse subtypes supports their use in broad geographic settings with locally circulating HIV clades and recombinant strains. Next-generation preclinical ultrasensitive p24 Ag assays achieved dramatically improved sensitivity, while rapid fourth-generation assays performed poorly for p24 Ag detection.

Performance of the Alere Determine™ HIV-1/2 Ag/Ab Combo Rapid Test with algorithm-defined acute HIV-1 infection specimens

BACKGROUND

The capacity of HIV Antigen/Antibody (Ag/Ab) immunoassays (IA) to detect HIV-1 p24 antigen has resulted in improved detection of HIV-1 infections in comparison to Ab-only screening assays. Since its introduction in the US, studies have shown that the Determine HIV-1/2 Ag/Ab Combo assay (Determine Ag/Ab) detects HIV infection earlier than laboratory-based IgM/IgG-sensitive IAs, but its sensitivity for HIV-1 p24 Ag detection is reduced compared to laboratory-based Ag/Ab assays. However, further evaluation is needed to assess its capacity to detect acute HIV-1 infection.

OBJECTIVE

To assess the performance of Determine Ag/Ab in serum from acute HIV-1 infections.

STUDY DESIGN

Select serum specimens that screened reactive on a laboratory-based Ag/Ab IA or IgM/IgG Ab-only IA, with a negative or indeterminate supplemental antibody test and detectable HIV-1 RNA were retrospectively tested with Determine Ag/Ab. Results were compared with those of the primary screening immunoassay to evaluate concordance within this set of algorithm-defined acute infections.

RESULTS

Of 159 algorithm-defined acute HIV-1 specimens, Determine Ag/Ab was reactive for 105 resulting in 66.0% concordance. Of 125 that were initially detected by a laboratory-based Ag/Ab IA, 81 (64.8%) were reactive by Determine Ag/Ab. A total of 34 acute specimens were initially detected by a laboratory-based IgM/IgG Ab-only IA and 24 (70.6%) of those were reactive by Determine Ag/Ab.

CONCLUSIONS

Due to their enhanced sensitivity, laboratory-based Ag/Ab IAs continue to be preferred over the Determine Ag/Ab as the screening method used by laboratories conducting HIV diagnostic testing on serum and plasma specimens.

The effect of oral preexposure prophylaxis on the progression of HIV-1 seroconversion

OBJECTIVE

To investigate whether oral preexposure prophylaxis (PrEP) alters timing and patterns of seroconversion when PrEP use continues after HIV-1 infection.

DESIGN

Retrospective testing of the timing of Fiebig stage HIV-1 seroconversion in the Partners PrEP Study, a randomized placebo-controlled clinical trial of PrEP conducted in Kenya and Uganda.

METHODS

Specimens from 138 seroconverters were collected every 3 months and when HIV-1 infection was suspected based on monthly rapid HIV-1 tests. Progression of seroconversion was compared between randomized groups (PrEP versus placebo) and per-protocol groups (placebo versus PrEP participants with detectable tenofovir during the seroconversion period) using laboratory assessment of Fiebig stage. Delay in site-detection of seroconversion and association with PrEP drug-regimen resistant virus were assessed using logistic regression. Analysis of time to each Fiebig stage used maximum likelihood estimation with a parametric model to accommodate the varying lengths of HIV-infection intervals.

RESULTS

There was a significant increase in delayed site detection of infection associated with PrEP (odds ratio = 3.49, P = 0.044). Delay in detection was not associated with increased risk of resistance in the PrEP arm (odds ratio = 0.93, P = 0.95). Estimated time to each Fiebig stage was elongated in seroconverters with evidence of ongoing PrEP use, significantly for only Stage 5 (28 versus 17 days, P = 0.05). Adjusted for Fiebig stage, viral RNA was ∼2/3 log lower in those assigned to PrEP compared with placebo; no differences were found in Architect signal to cut-off at any stage.

CONCLUSION

Ongoing PrEP use in seroconverters may delay detection of infection and elongate seroconversion, although the delay does not increase risk of resistance.

Human Immunodeficiency Virus

In this chapter we will discuss the diagnosis and monitoring of individuals with HIV infection. The application and interpretation of these tests does not change dramatically when used in the immunocompromised host. The principal approach to the diagnosis of HIV infection involves serologic testing, although nucleic acid amplification tests play an important role in the diagnosis of acute HIV infection. The algorithm for diagnosis of HIV continues to evolve with newer assays that are able to detect infection within an earlier timeframe after HIV transmission. Viral load testing for HIV-1 is the cornerstone for monitoring patients on antiretroviral therapy. Genotypic and phenotypic resistance tests are employed when antiretroviral resistance is suspected and results help guide therapy. The tropism assay must be performed to determine the efficacy of CCR5 chemokine receptor antagonists. Next-generation sequencing methods are an innovative approach to assessing archived antiretroviral resistance in patients with virologic suppression. The success of antiretroviral therapy with improved long-term outcomes has made transplantation in HIV-infected patients a reality.

Early and Delayed Antiretroviral Therapy Results in Comparable Reductions in CD8+ T Cell Exhaustion Marker Expression

In untreated HIV infection, CD8+ T cell exhaustion (i.e., decreased proliferative and effector capacity) is associated with high levels of expression of coinhibitory receptors, including PD-1, T cell immunoreceptor with Ig and ITIM domains (TIGIT), CD160, and 2B4. This is evident for both HIV-specific and non-HIV-specific CD8+ T cells. Antiretroviral therapy (ART) initiated during chronic infection decreases but may not completely normalize the expression of such "exhaustion markers." Compared to initiation of ART later in the course of disease, initiation soon after infection reduces some parameters of chronic inflammation and adaptive immune dysfunction. However, it is not known if Early ART (e.g., initiated within the first 6 months after HIV infection) versus Delayed ART (e.g., initiated during chronic infection) preferentially reduces expression of exhaustion markers. We evaluated exhaustion marker expression on subsets of circulating effector and memory CD8+ T cells at longitudinal pre- and post-ART (2 and 5 years on ART) time points from n = 19 (Early ART) and n = 23 (Delayed ART) individuals. Before ART, TIGIT and CD160 were expressed on a statistically significantly higher proportion of effector and transitional memory cells from individuals in the Delayed ART group: the timing of ART initiation, however, did not consistently affect the expression of the exhaustion markers once viral suppression was achieved. Understanding which factors do and do not regulate aspects of CD8+ T cell exhaustion, including the expression of exhaustion markers, is critical to inform the rational design of CD8+ T cell-based therapies to treat HIV, for which CD8+ T cell exhaustion remains an important barrier to efficacy.

Performance of the Bio-Rad Geenius HIV1/2 Supplemental Assay in Detecting "Recent" HIV Infection and Calculating Population Incidence

Objective:

HIV seroconversion biomarkers are being used in cross-sectional studies for HIV incidence estimation. Bio-Rad Geenius HIV-1/2 Supplemental Assay is an immunochromatographic single-use assay that measures antibodies (Ab) against multiple HIV-1/2 antigens. The objective of this study was to determine whether the Geenius assay could additionally be used for recency estimation.

Design:

This assay was developed for HIV-1/2 confirmation; however, quantitative data acquired give information on increasing concentration and diversity of antibody responses over time during seroconversion. A quantitative threshold of recent HIV infection was proposed to determine “recent” or “nonrecent” HIV infection; performance using this cutoff was evaluated.

Methods:

We tested 2500 highly characterized specimens from research subjects in the United States, Brazil, and Africa with well-defined durations of HIV infection. Regression and frequency estimation were used to estimate assay properties relevant to HIV incidence measurement: mean duration of recent infection (MDRI), false-recent rate, and assay reproducibility and robustness.

Results:

Using the manufacturer's proposed cutoff index of 1.5 to identify “recent” infection, the assay has an estimated false-recent rate of 4.1% (95% CI: 2.2 to 7.0) and MDRI of 179 days (155 to 201) in specimens from treatment-naive subjects, presenting performance challenges similar to other incidence assays. Lower index cutoffs associated with lower MDRI gave a lower rate of false-recent results.

Conclusions:

These data suggest that with additional interpretive analysis of the band intensities using an algorithm and cutoff, the Geenius HIV-1/2 Supplemental Assay can be used to identify recent HIV infection in addition to confirming the presence of HIV-1 and HIV-2 antibodies.

Evaluation of dried blood spot protocols with the Bio-Rad GS HIV Combo Ag/Ab EIA and Geenius™ HIV 1/2 Supplemental Assay

OBJECTIVE

FDA-approved antigen/antibody combo and HIV-1/2 differentiation supplemental tests do not have claims for dried blood spot (DBS) use. We compared two DBS-modified protocols, the Bio-Rad GS HIV Combo Ag/Ab (BRC) EIA and Geenius™ HIV-1/2 (Geenius) Supplemental Assay, to plasma protocols and evaluated them in the CDC/APHL HIV diagnostic algorithm.

METHODS

BRC-DBS p24 analytical sensitivity was calculated from serial dilutions of p24. DBS specimens included 11 HIV-1 seroconverters, 151 HIV-1-positive individuals, including 20 on antiretroviral therapy, 31 HIV-2-positive and one HIV-1/HIV-2-positive individuals. BRC-reactive specimens were tested with Geenius using the same DBS eluate. Matched plasma specimens were tested with BRC, an IgG/IgM immunoassay and Geenius. DBS and plasma results were compared using the McNemar's test. A DBS-algorithm applied to 348 DBS from high-risk individuals who participated in surveillance was compared to HIV status based on local testing algorithms.

RESULTS

BRC-DBS detects p24 at a concentration 18 times higher than in plasma. In seroconverters, BRC-DBS detected more infections than the IgG/IgM immunoassay in plasma (p=0.0133), but fewer infections than BRC-plasma (p=0.0133). In addition, the BRC/Geenius-plasma algorithm identified more HIV-1 infections than the BRC/Geenius-DBS algorithm (p=0.0455). The DBS protocols correctly identified HIV status for established HIV-1 infections, including those on therapy, HIV-2 infections, and surveillance specimens.

CONCLUSIONS

The DBS protocols exhibited promising performance and allowed rapid supplemental testing. Although the DBS algorithm missed some early infections, it showed similar results when applied to specimens from a high-risk population. Implementation of a DBS algorithm would benefit testing programs without capacity for venipuncture.

Performance evaluation of the FDA-approved Determine™ HIV-1/2 Ag/Ab Combo assay using plasma and whole blood specimens

BACKGROUND

The Determine™ HIV-1/2 Ag/Ab Combo (DC) rapid test can identify HIV-1 infection earlier than rapid antibody-only tests in plasma specimens.

OBJECTIVES

We compared the performance of DC with a laboratory-based antigen/antibody (Ag/Ab) combo assay in plasma and evaluated antigen reactivity in whole blood specimens.

STUDY DESIGN

We tested by DC 508 plasma specimens collected in a prospective study and 107 sequential plasma and simulated whole blood specimens from 20 seroconversion panels. Previous results using the ARCHITECT (ARC) Ag/Ab combo assay were compared to DC results. In seroconversion panels, the days from the first HIV1 RNA-positive test to first DC-reactive in plasma and whole blood was compared. McNemar's and Wilcoxon signed rank tests were used for statistical analysis.

RESULTS

Of 415 HIV-positive samples, ARC detected 396 (95.4%) and DC 337 (81.2%) (p<0.0001). DC was reactive in 50.0% of ARC-reactive/MS-negative, 78.6% of ARC-reactive/MS-indeterminate, and 99.6% of ARC-reactive/MS-HIV-1-positive or -undifferentiated specimens. DC antigen reactivity was higher among ARC-reactive/MS-negative than MS-indeterminate samples. In 20 HIV-1 seroconversion panels, there was a significant difference between DC reactivity in plasma (91.1%) and whole blood (56.4%) (p<0.0001). DC with whole blood showed a significant delay in reactivity compared to plasma (p=0.008).

CONCLUSIONS

In plasma, DC was significantly less sensitive than an instrumented laboratory-based Ag/Ab combo assay. DC in plasma was significantly more sensitive compared to whole blood in early HIV-1 infections. With the U.S. laboratory-based diagnostic algorithm, DC as the first step would likely miss a high proportion of HIV-1 infections in early stages of seroconversion.

Performance evaluation of the point-of-care INSTI™ HIV-1/2 antibody test in early and established HIV infections

BACKGROUND

The flow-through INSTI™ HIV-1/HIV-2 Rapid Antibody (INSTI) test is a 60s FDA-approved test for HIV-1 and HIV-2 antibody testing using whole blood and plasma.

OBJECTIVE

We evaluated the performance of INSTI using plasma and simulated whole blood specimens.

STUDY DESIGN

INSTI's performance in plasma specimens from commercial seroconversion panels was assessed by estimating the relative sensitivity using a 50% cumulative frequency analysis and by comparing its performance with other FDA-approved rapid tests (RTs). INSTI was further evaluated using 320 HIV-1 plasma specimens collected during a cross-sectional study and with 107 HIV-1 and 24 HIV-2 simulated whole blood specimens. Sensitivity and specificity were calculated using 615 known HIV-1 group M/O and 80 HIV-2 (Western blot (WB)-positive), and 497 HIV-negative plasma specimens, respectively.

RESULTS

In HIV-1 seroconversion panels, INSTI became reactive 9days before a positive WB. When compared to FDA-approved antibody-based lateral flow RTs, INSTI detected significantly more early infections. Among HIV-1-infected cross-sectional plasma samples, INSTI detected 23 (27%) of 85 Architect-positive/Multispot-negative or indeterminate specimens. For plasma specimens, the sensitivity was 99.84% for HIV-1 and 100% for HIV-2, and the specificity was 99.80%. Using simulated whole blood from seroconverters, INSTI performed similarly to plasma.

CONCLUSIONS

INSTI performed significantly better than antibody-based lateral flow RTs during early stages of seroconversion. Sensitivity and specificity were within the manufacturer's reported ranges. Considering the observed test performance and the almost immediate results, INSTI is an accurate option to detect HIV-1/HIV-2 antibodies in point-of-care settings where lab testing is not feasible.

Estimating HIV Incidence Using a Cross-Sectional Survey: Comparison of Three Approaches in a Hyperendemic Setting, Ndhiwa Subcounty, Kenya, 2012

OBJECTIVES

Estimating HIV incidence is critical for identifying groups at risk for HIV infection, planning and targeting interventions, and evaluating these interventions over time. The use of reliable estimation methods for HIV incidence is thus of high importance. The aim of this study was to compare methods for estimating HIV incidence in a population-based cross-sectional survey.

DESIGN/METHODS

The incidence estimation methods evaluated included assay-derived methods, a testing history-derived method, and a probability-based method applied to data from the Ndhiwa HIV Impact in Population Survey (NHIPS). Incidence rates by sex and age and cumulative incidence as a function of age were presented.

RESULTS

HIV incidence ranged from 1.38 [95% confidence interval (CI) 0.67-2.09] to 3.30 [95% CI 2.78-3.82] per 100 person-years overall; 0.59 [95% CI 0.00-1.34] to 2.89 [95% CI 0.86-6.45] in men; and 1.62 [95% CI 0.16-6.04] to 4.03 [95% CI 3.30-4.77] per 100 person-years in women. Women had higher incidence rates than men for all methods. Incidence rates were highest among women aged 15-24 and 25-34 years and highest among men aged 25-34 years.

CONCLUSION

Comparison of different methods showed variations in incidence estimates, but they were in agreement to identify most-at-risk groups. The use and comparison of several distinct approaches for estimating incidence are important to provide the best-supported estimate of HIV incidence in the population.

Human immunodeficiency virus: Diagnostic approach

First descriptions of acquired immunodeficiency syndrome appeared in 1981. Four years later the causative agent was cultured which lead to development and production of tests that helped healthcare providers to identify persons living with HIV. Currently, diagnosis of HIV is performed with fourth generation immunoassays (those that detect p24 antigen together with IgM and IgG antibodies to HIV-1 and -2) which if positive need to be followed by an assay that can differentiate between HIV-1 and HIV-2 viruses. The Western blot is no longer used to confirm HIV infections per CDC guidelines. In case there is a positive fourth generation assay but negative differentiation assay, nucleic acid testing for HIV-1 should be performed. This algorithm allows for detection of acute infections. Alternatively, the World Health Organization has algorithms that use rapid testing for diagnosis of HIV infections. This review will describe the evolution of tests and diagnostic algorithms from the 1980s to the current state. Special situations regarding diagnosis will also be discussed.

Comparative performance of the Geenius™ HIV-1/HIV-2 supplemental test in Florida's public health testing population

BACKGROUND

The Centers for Disease Control and Prevention (CDC) published updated guidelines in 2014 for the laboratory diagnosis of HIV in the United States, which recommend use of a supplemental immunoassay (IA) that differentiates HIV-1 from HIV-2 after a repeatedly reactive HIV-1/2 antigen/antibody "Combo" screening test. In October 2014, Bio-Rad Laboratories introduced the FDA-cleared Geenius HIV-1/HIV-2 Supplemental assay and in July 2016, it replaced the Multispot HIV-1/HIV-2 differentiation rapid test as the second test in the HIV diagnostic algorithm.

OBJECTIVE

To compare performance of the new FDA-cleared Bio-Rad Geenius HIV-1/HIV-2 Supplemental assay and the Bio-Rad Multispot HIV-1/HIV-2 differentiation assay for use as the primary supplemental test in the 2014 CDC/APHL HIV Diagnostic Algorithm.

STUDY DESIGN

Two sets of specimens were used to assess the performance of Geenius; 340 select retrospective specimens, obtained through routine clinical submissions from individuals seeking HIV serostatus determinations and 10 known HIV-2 antibody reactive specimens provided by Bio-Rad Laboratories. Panels were created and characterized solely by in-house laboratory results. The panels consisted of: algorithm-defined "established HIV-1 infections" (n=250), "acute HIV-1 infections" (n=20), "early HIV-1 infections" (n=10) and "false positive Combo specimens" (n=60).

RESULTS

CONCLUSIONS: The Geenius assay provides significant advantages over Multispot as an appropriate replacement for the primary supplemental test in the HIV Diagnostic Algorithm. In this retrospective study, Geenius was highly concordant with Multispot, reclassified some acute and early algorithm-defined HIV-1 positive specimens and demonstrated a potential decrease in the number HIV-1 RNA nucleic acid amplification tests needed to complete the diagnostic algorithm.

Current diagnostic methods for HIV

Detection of HIV infection is essential for diagnosis and monitoring of the infection. There are different types of diagnostic tools available that are based on detection of HIV-specific antibodies, viral antigen or nucleic acid. Sensitivities and specificities of assays utilized for HIV detection have improved. Newer HIV testing technologies such as third-generation enzyme immunoassay which detect HIV-specific IgG and IgM antibodies, fourth-generation enzyme immunoassay which detect both anti-HIV antibodies and HIV p24 antigen and nucleic acid based tests for HIV RNA have significantly decreased the window period. This review provides an overview of current technologies for the detection and monitoring of HIV infection and recent advances in the field of HIV diagnosis.

Multi-centre field evaluation of the performance of the Trinity Biotech Uni-Gold HIV 1/2 rapid test as a first-line screening assay for gay and bisexual men compared with 4th generation laboratory immunoassays

BACKGROUND

The Trinity Biotech Uni-Gold HIV test (Uni-Gold) is often used as a supplementary rapid test in testing algorithms.

OBJECTIVE

To evaluate the operational performance of the Uni-Gold as a first-line screening test among gay and bisexual men (GBM) in a setting where 4th generation HIV laboratory assays are routinely used.

STUDY DESIGN

We compared the performance of Uni-Gold with conventional HIV serology conducted in parallel among GBM attending 22 testing sites. Sensitivity was calculated separately for acute and established infection, defined using 4th generation screening Ag/Ab immunoassay (EIA) and Western blot results. Previous HIV testing history and results of supplementary 3rd generation HIV Ab EIA, and p24 antigen EIA were used to further characterise cases of acute infection.

RESULTS

Of 10,793 specimens tested with Uni-Gold and conventional serology, 94 (0.90%, 95%CI:0.70-1.07) were confirmed as HIV-positive by conventional serology, and 37 (39.4%) were classified as acute infection. Uni-Gold sensitivity was 81.9% overall (77/94, 95%CI:72.6-89.1); 56.8% for acute infection (21/37, 95%CI:39.5-72.9) and 98.2% for established infection (56/57, 95%CI:90.6-100.0). Of 17 false non-reactive Uni-Gold results, 16 were acute infections, and of these seven were p24 antigen reactive but antibody negative. Uni-Gold specificity was 99.9% (10,692/10,699, 95%CI:99.9-100.0), PPV was 91.7% (95%CI:83.6-96.6) and NPV was 99.8% (95%CI:99.7-99.9), respectively.

CONCLUSIONS

In this population, Uni-Gold had good specificity and sensitivity was high for established infections when compared to 4th generation laboratory assays, however sensitivity was lower in acute infections. Where rapid tests are used in populations with a high proportion of acute infections, additional testing strategies are needed to detect acute infections.

Time Until Emergence of HIV Test Reactivity Following Infection With HIV-1: Implications for Interpreting Test Results and Retesting After Exposure

BACKGROUND

 Understanding the period of time between an exposure resulting in infection with human immunodeficiency virus (HIV) and when a test can reliably detect the presence of that infection, that is, the test window period, may benefit testing programs and clinicians in counseling patients about when the clinician and the patient can be confident a suspected exposure did not result in HIV infection.

METHODS

 We evaluated the intervals between reactivity of the Aptima HIV-1 RNA test (Aptima) and 20 US Food and Drug Administration-approved HIV immunoassays using 222 longitudinally collected plasma specimens from HIV-1 seroconverters from the United States. Using interval-censored survival and binomial regression approaches a multi-model framework was implemented to estimate the relative emergence of test reactivity, referred to here as an inter-test reactivity interval (ITRI). We then combined ITRI results with simulated data for the eclipse period, the time between exposure and detection of HIV virus by Aptima, to estimate the window period for each test.

RESULTS

 The estimated ITRIs were shorter with each new class of HIV tests, ranging from 5.9 to 24.8 days. The 99^th percentiles of the window period probability distribution ranged from 44 days for laboratory screening tests that detect both antigen and antibody to 65 days for the Western blot test.

CONCLUSIONS

 Our directly comparable estimates of the emergence of reactivity for 20 immunoassays are valuable to testing providers for interpreting negative HIV test results obtained shortly after exposure, and for counseling individuals on when to retest after an exposure.

Viral load criteria and threshold optimization to improve HIV incidence assay characteristics

OBJECTIVE

Assays for classifying HIV infections as 'recent' or 'nonrecent' for incidence surveillance fail to simultaneously achieve large mean durations of 'recent' infection (MDRIs) and low 'false-recent' rates (FRRs), particularly in virally suppressed persons. The potential for optimizing recent infection testing algorithms (RITAs), by introducing viral load criteria and tuning thresholds used to dichotomize quantitative measures, is explored.

DESIGN

The Consortium for the Evaluation and Performance of HIV Incidence Assays characterized over 2000 possible RITAs constructed from seven assays (Limiting Antigen, BED, Less-sensitive Vitros, Vitros Avidity, BioRad Avidity, Architect Avidity, and Geenius) applied to 2500 diverse specimens.

METHODS

MDRIs were estimated using regression, and FRRs as observed 'recent' proportions, in various specimen sets. Context-specific FRRs were estimated for hypothetical scenarios. FRRs were made directly comparable by constructing RITAs with the same MDRI through the tuning of thresholds. RITA utility was summarized by the precision of incidence estimation.

RESULTS

All assays produce high FRRs among treated patients and elite controllers (10-80%). Viral load testing reduces FRRs, but diminishes MDRIs. Context-specific FRRs vary substantially by scenario - BioRad Avidity and Limiting Antigen provided the lowest FRRs and highest incidence precision in scenarios considered.

CONCLUSION

The introduction of a low viral load threshold provides crucial improvements in RITAs. However, it does not eliminate nonzero FRRs, and MDRIs must be consistently estimated. The tuning of thresholds is essential for comparing and optimizing the use of assays. The translation of directly measured FRRs into context-specific FRRs critically affects their magnitudes and our understanding of the utility of assays.

Sensitivity of HIV rapid tests compared with fourth-generation enzyme immunoassays or HIV RNA tests

OBJECTIVE

Determine the sensitivity of HIV rapid tests compared with fourth-generation enzyme immunoassays (EIA) or nucleic acid amplification tests (NAAT) in clinical settings.

DESIGN

Systematic review and meta-analysis.

METHODS

Medline, PubMed, Embase, Cochrane Controlled Trials Register, Cochrane reviews and Cumulative Index to Nursing and Allied Health Literature were searched until 14 July 2015 for studies of adults comparing point-of-care HIV rapid tests to fourth-generation HIV EIA antibody/p24 antigen or HIV NAAT.

RESULTS

From 953 titles, 18 studies were included, involving 110 122 HIV rapid test results. Compared with EIA, the estimated sensitivity (random effects) of HIV rapid tests was 94.5% [95% confidence interval (CI): 87.4-97.7]. Compared with NAAT, the sensitivity of HIV rapid tests was 93.7% (95% CI: 88.7-96.5). The sensitivity of HIV rapid tests in high-income countries was 85.7% (95% CI: 81.9-88.9) and in low-income countries was 97.7% (95% CI: 95.2-98.9) compared with either EIA or NAAT (P < 0.01 for difference between settings). Proportions of antibody negative acute infections were 13.6 (95% CI: 10.1-18.0) and 4.7% (95% CI: 2.8-7.7) in studies from high-income and low-income countries, respectively (P < 0.01).

CONCLUSION

In clinical settings, HIV rapid tests were less sensitive in high-income countries compared with low-income countries, missing about one in seven infections, possibly because of the larger proportion of acute infections in targeted populations. This suggests that in high-income countries, HIV rapid tests should be used in combination with fourth-generation EIA or NAAT tests, except in special circumstances. Prospective Registration of Systematic Reviews registration number CRD42015020154.Supplementary video link: http://links.lww.com/QAD/A924.

Cost-Effectiveness of Frequent HIV Testing of High-Risk Populations in the United States

PURPOSE

Data showing a high incidence of HIV infection among men who have sex with men (MSM) who had annual testing suggest that more frequent HIV testing may be warranted. Testing technology is also a consideration given the availability of sensitive testing modalities and the increased use of less-sensitive rapid, point-of-care antibody tests. We assessed the cost-effectiveness of HIV testing of MSM and injection drug users (IDUs) at 3- and 6-month intervals using fourth-generation and rapid tests.

METHODS

We used a published mathematical model of HIV transmission to evaluate testing intervals for each population using cohorts of 10,000 MSM and IDU. We incorporated HIV transmissions averted due to serostatus awareness and viral suppression. We included costs for HIV testing and treatment initiation, and also treatment costs saved from averted transmissions.

RESULTS

For MSM, HIV testing was cost saving or cost effective over a 1-year period for both 6-month compared with annual testing and quarterly compared with 6-month testing using either test. Testing IDU every 6 months compared with annually was moderately cost effective over a 1-year period with a fourth-generation test, while testing with rapid, point-of-care tests or quarterly was not cost effective. MSM results remained robust in sensitivity analysis, whereas IDU results were sensitive to changes in HIV incidence and continuum-of-care parameters. Threshold analyses on costs suggested that additional implementation costs could be incurred for more frequent testing for MSM while remaining cost effective.

CONCLUSIONS

HIV testing of MSM as frequently as quarterly is cost effective compared with annual testing, but testing IDU more frequently than annually is generally not cost effective.

Initiation of Antiretroviral Therapy During Acute HIV-1 Infection Leads to a High Rate of Nonreactive HIV Serology

BACKGROUND

Third- and fourth-generation immunoassays (IAs) are widely used in the diagnosis of human immunodeficiency virus (HIV) infection. Antiretroviral therapy (ART) during acute HIV infection (AHI) may impact HIV-specific antibodies, with failure to develop antibody or seroreversion. We report on the ability of diagnostic tests to detect HIV-specific antibodies in Thai participants initiating ART during AHI.

METHODS

Participants with detectable plasma HIV RNA but nonreactive HIV-specific immunoglobulin G, enrolled in an AHI study, were offered immediate initiation of ART. Participants were tested at initiation and at 12 and 24 weeks following treatment using standard second-, third-, and fourth-generation IAs and Western blot (WB).

RESULTS

Participants (N = 234) initiating ART at a median of 19 days (range, 1-62 days) from HIV exposure demonstrated different frequencies of reactivity prior to and following 24 weeks of ART depending on the IA. Third-generation IA nonreactivity prior to ART was 48%, which decreased to 4% following ART (P < .001). Fourth-generation IA nonreactivity was 18% prior to ART and 17% following ART (P = .720). Negative WB results were observed in 89% and 12% of participants prior to and following 24 weeks of ART, respectively (P < .001). Seroreversion to nonreactivity during ART was observed to at least one of the tests in 20% of participants, with fourth-generation IA demonstrating the highest frequency (11%) of seroreversion.

CONCLUSIONS

HIV-specific antibodies may fail to develop and, when detected, may decline when ART is initiated during AHI. Although fourth-generation IA was the most sensitive at detecting AHI prior to ART, third-generation IA was the most sensitive during treatment.

CLINICAL TRIALS REGISTRATION

NCT00796146 and NCT00796263.

Acute infections, cost and time to reporting of HIV test results in three U.S. State Public Health Laboratories

OBJECTIVE

In three U.S. State Public Health Laboratories (PHLs) using a fourth-generation immunoassay (IA), an HIV-1/HIV-2 differentiation antibody IA and a nucleic acid test (NAT), we characterized the yield and time to reporting of acute infections, and cost per positive specimen.

METHODS

Routine HIV testing data were collected from July 1, 2012-June 30, 2013 for Massachusetts and Maryland PHLs, and from November 27, 2012-June 30, 2013 for Michigan PHL. Massachusetts and Michigan used fourth-generation and differentiation IAs with NAT conducted by a referral laboratory. In Maryland, fourth-generation IA repeatedly reactive specimens were followed by a Western blot (WB), and those with negative or indeterminate results were tested with a differentiation IA and HIV-1 NAT, and if positive by NAT, confirmed by a different HIV-1 NAT. Specimens from WB-positive persons at risk for HIV-2 were tested with a differentiation IA and, if positive, with an HIV-2 WB and/or differential HIV-1/HIV-2 proviral DNA polymerase chain reaction.

RESULTS

Among 7914 specimens from Massachusetts PHL, 6069 from Michigan PHL, and 36,266 from Maryland PHL, 0.10%, 0.02% and 0.05% acute infections were identified, respectively. Massachusetts and Maryland PHLs each had 1 HIV-2 positive specimen. The median time from specimen receipt to laboratory reporting of results for acute infections at Massachusetts, Michigan and Maryland PHLs was 8, 11, and 7 days respectively. The laboratory cost per HIV positive specimen was $336 (Massachusetts), $263 (Michigan) and $210 (Maryland).

CONCLUSIONS

Acute and established infections were found by PHLs using fourth-generation IA in conjunction with antibody tests and NAT. Time to reporting of acute HIV test results to clients was suboptimal, and needs to be streamlined to expedite treatment and interrupt transmission.

HIV testing updates and challenges: when regulatory caution and public health imperatives collide

Numerous improvements in HIV testing technology led recently to the first revision of recommendations for diagnostic laboratory testing in the USA in 25 years. Developments in HIV testing continue to produce tests that identify HIV infection earlier with faster turnaround times for test results. These play an important role in identifying HIV infection during the highly infectious acute phase, which has implication for both patient management and public health interventions to control the spread of HIV. Access to these developments, however, is often delayed by the regulatory apparatus for approval and oversight of HIV testing in the USA. This article summarizes recent developments in HIV diagnostic testing technology, outlines their implications for clinical management and public health, describes current systems of regulatory oversight for HIV testing in the USA, and proposes alternatives that could expedite access to improved tests as they become available.

HIV testing patterns for United States Air Force personnel, 2008-2012

OBJECTIVE

This study evaluated 3rd generation human immunodeficiency virus (HIV) test patterns and HIV infection rates in the United States Air Force (USAF).

STUDY DESIGN

Retrospective database study.

METHODS

HIV enzyme-linked immunoassay (ELISA) and Western blot tests were analysed for all USAF personnel from 2008 to 2012. For new HIV cases, unadjusted and adjusted annual rates were calculated per 100,000 persons.

RESULTS

In total, 1,608,665 tests were performed in 626,298 individuals, with a reactive ELISA observed in 809 (0.001%) persons. Western blot (n = 1949) results included 378 (19.4%) positive, 1283 (65.8%) negative, and 288 (15.0%) indeterminate (WBi). Unadjusted annual HIV rates were between 16.7 and 20.6 per 100,000 persons during the study period. The overall age-adjusted rate was 14.8 cases per 100,000 persons tested. Blacks/African Americans had the highest risk of HIV (risk ratio 7.9 [95% confidence interval 5.78, 9.95] compared to Whites).

CONCLUSIONS

WBi results, which can cause delays in determining HIV status, were relatively common with the 3rd generation assay. However, this will be mitigated by a planned transition to a 4th generation assay. Although the overall rate of HIV in the USAF is lower than US civilian adults, HIV prevention efforts targeting young Blacks/African Americans may help to reduce HIV incidence in the USAF.

Performance of Determine Combo and other point-of-care HIV tests among Seattle MSM

BACKGROUND AND OBJECTIVE

The rapid test study was a real-time comparison of point-of-care (POC) HIV tests to determine their abilities to detect early HIV infection.

STUDY DESIGN

Men and transgender persons reporting sex with men in the prior year were recruited at the Public Health-Seattle & King County STD Clinic, Gay City Health Project, and University of Washington Primary Infection Clinic. Study tests included the OraQuick ADVANCE Rapid HIV-1/2 Antibody Test performed on oral fluids and tests performed on fingerstick whole blood specimens including OraQuick, Uni-Gold Recombigen HIV test, Determine HIV-1/2 Ag/Ab Combo, and INSTI HIV-1 Rapid Antibody Test. Specimens from subjects with negative results were sent for EIA and nucleic acid amplification testing. McNemar's exact tests compared the numbers of HIV-infected subjects detected.

RESULTS

Between February 2010 and August 2014, there were 3438 study visits. Twenty-four subjects had discordant POC results with at least one reactive and one non-reactive test, including one subject with a reactive Determine p24 antigen. OraQuick performed on oral fluids identified fewer persons compared to all fingerstick tests. OraQuick performed on fingerstick whole blood detected fewer persons compared to the Determine Combo antibody component (p=.008) and Combo overall (p=.004), and there was a trend when compared to INSTI (p=.06). The Determine Combo specificity was 98.99%.

CONCLUSIONS

As reported by others, Determine Combo underperforms compared to laboratory-based testing, but it did detect one acute infection. If these results are validated, the specificity of Determine Combo may limit its usefulness in populations with lower HIV incidence.

Rationale and design of FORTH: a randomised controlled trial assessing the effectiveness of HIV self-testing in increasing HIV testing frequency among gay and bisexual men

BACKGROUND

Gay and bisexual men (GBM) are a major risk group for HIV acquisition, yet the majority of higher-risk GBM test for HIV less often than recommended (3-6 monthly). HIV self-testing has the potential to increase testing frequency and improve awareness of personal HIV status. HIV self-tests have been approved in some countries, however there are concerns whether self-testing would increase HIV testing frequency enough to compensate for the reduced sensitivity of self-tests in early infection. We describe here a randomised controlled trial to assess the effectiveness of self-testing in increasing HIV testing frequency among higher-risk GBM, and its acceptability.

METHODS/DESIGN

Participants are higher-risk HIV negative GBM (>5 partners or condomless anal intercourse in previous 3 months; n = 350), including 50 GBM who tested for HIV over two years ago or never tested before ('infrequent-testers'). Participants are recruited from sexual health clinics and community-based organisations, and randomised 1:1 to either self-testing or standard-care (routine clinic-based testing) arms. The trial employs a wait-list control design: participants in the standard-care arm switch to self-testing arm in the second year, and gain access to self-test kits. Participants in the self-testing arm receive four oral-fluid self-test kits at enrolment, with additional kits provided on request. Demographics, sexual behaviour and HIV testing preferences are collected at baseline, and the frequency and pattern of HIV and sexually transmissible infection (STI) testing is collected via online 3-monthly questionnaires. The acceptability of self-testing is assessed at 12 months via an online questionnaire and in-depth interviews. A 24-h telephone support is provided, with expedited follow-up of those with reactive self-test results. The primary outcome is HIV testing frequency (mean number of HIV tests per person) over 12 months, and the secondary outcomes are: mean number of STI tests (chlamydia, gonorrhoea, syphilis) per person; reasons for HIV testing; and acceptability of HIV self-testing.

DISCUSSION

This is the first trial to evaluate the use of self-testing among GBM in Australia, and the first internationally among infrequent testers. The study will provide evidence on whether self-testing increases HIV testing frequency, and its acceptability among GBM. The findings will improve our understanding of self-testing patterns, and whether GBM supplement or replace their existing testing routine.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trial Registration number: ACTRN12613001236785 , registered on November 12, 2013.

Luminex xMAP combined with Western blot improves HIV diagnostic sensitivity

Currently, Western blot is used to confirm the initial serodiagnosis of HIV infection by antibody detection. However, a major deficiency of the Western blot relates to a lack of sufficient sensitivity in detecting HIV antibodies. This report describes a simple, sensitive and inexpensive bead-based assay for detection of early HIV infection. A panel of 138 positive specimens including 105 blood donors and 33 MSM with known Western blot results were evaluated using Luminex xMAP at Tianjin Centers for Disease Control and Prevention (CDC). We demonstrate a superior sensitivity of Luminex xMAP compared with Western blot. Of the 87 confirmed HIV positive blood donors, Western blot only confirmed 65 cases with 74.7% (65/87) sensitivity while Luminex xMAP identified 72 cases with 82.8% (72/87) sensitivity (p<0.05). Western blot and Luminex xMAP verified 13 and 19 of 33 MSM specimens, respectively. The sensitivity was 39.4% (13/33) for Western blot and 57.6% (19/33) for Luminex xMAP (p<0.1). Luminex xMAP combined with Western blot improves the diagnostic sensitivity of HIV infection at an early stage, and reduces the chances of missed diagnosis.

Performance evaluation of the CHEMBIO DPP® (dual path platform) HIV-1/2 assay in early and established infections

BACKGROUND

The availability of more accurate point-of-care technology could increase the number of persons aware of their HIV status. The DPP(®) HIV-1/2 assay is the first dual path platform rapid test (RT) approved in the U.S. that also received the Clinical Laboratory Improvement Amendments (CLIA) waiver for use with oral fluid and fingerstick and venous whole blood.

OBJECTIVE

To evaluate the performance of the DPP(®) HIV-1/2 assay with plasma specimens.

STUDY DESIGN

Sensitivity and specificity of the assay were calculated from 696 HIV-1 groups M (B and non-B subtypes) and O and HIV-2 (groups A and B) specimens and 505 HIV-negative specimens, respectively. Analysis of the assay performance in HIV-1 early infections was assessed by estimating the relative sensitivity of the RT before the Western blot (WB) becomes positive using a 50% cumulative frequency analysis and by comparing the reactivity with other Food and Drug Administration (FDA)-approved RTs.

RESULTS

The sensitivity for established infection was 100% for HIV-1 and 100% for HIV-2. The specificity was 100%. The DPP(®) HIV-1/2 assay performs similarly to most antibody-based RT approved by FDA in early HIV-1 infections.

CONCLUSIONS

The DPP(®) technology showed no significant improvement for detecting early infections over other lateral-flow RTs used in the U.S. Without more data on the DPP(®) HIV-1/2 assay, especially from whole blood and oral fluid specimens collected during the early phase of infection, its performance as point-of-care technology remains to be assessed.