Human Immunodeficiency Virus P24 Antigen Research Articles

HIV-1 Tat is present in the serum of people living with HIV-1 despite viral suppression

ObjectivesDespite successful human immunodeficiency virus (HIV) control with combination antiretroviral therapy (cART), individuals with HIV still face health risks, including cancers, cardiovascular and neurocognitive diseases. An HIV protein, Tat, is potentially involved in these HIV-related diseases. Previous studies demonstrated circulating Tat in the blood of untreated people with HIV. Here, we measured Tat levels in the serum of cART-treated people with HIV to examine the effect of cART on Tat production. MethodsSerum samples from 63 HIV-positive and 20 HIV-seronegative individuals were analyzed using an ELISA assay that detected Tat concentrations above 2.5 ng/mL. ResultsAmong HIV-positive individuals, the Tat level ranged from 0 to 14 ng/mL. 25.4% (16 out of 63) exceeded the 2.5 ng/mL cut-off, with a median HIV Tat level of 4.518 [3.329-8.120] ng/mL. No correlation was revealed between Tat levels and CD4+ T cell counts, serum HIV RNA, p24 antigen, or anti-Tat levels. ConclusionsDespite cART, circulating HIV Tat persists and may contribute to HIV-related diseases. This emphasizes the need for further research on the mechanisms of Tat action in non-infected cells where it can penetrate upon circulation in the blood.

Human Immunodeficiency Virus in Adults Undergoing Surgery for Brain Tumors.

IntroductionEarly diagnosis and treatment of human immunodeficiency virus (HIV) can improve outcomes. HIV prevalence in brain tumor patients and the impact of an HIV diagnosis on patient outcomes are poorly understood.Materials and methodsThis was a prospective study of 100 consecutive brain tumor patients admitted to a Greater London Tertiary Neurosurgical center for surgery between January 2021 and October 2021. All brain tumors were included. All patients have appropriately consented. Blood was tested to detect HIV antibodies and p24 antigen. Outcomes were noted at 30-day postoperative follow-up.ResultsIn 100 patients, there was one case of a known HIV-positive, seronegative patient, and no new diagnosis was made, giving a prevalence of 1%. The mean age of patients included was 61.7 ± 13.3, with 57% female. The patient with HIV suffered a postoperative pseudomonas infection, requiring intensive care, additional surgery, and antibiotics. This resulted in an inpatient stay of 55 days - an increase of 274% compared to patients without HIV.ConclusionLiterature regarding the prevalence of HIV in glioma patients is inconclusive, of low quality, and primarily out-of-date. Our literature search found no similar study of rates of HIV in brain tumor patients in the United Kingdom. The incidence of both HIV and brain tumors, particularly glioblastomas, is low.

Visible 405 nm Violet-Blue Light Successfully Inactivates HIV-1 in Human Plasma.

Despite significant advances in ensuring the safety of the blood supply, there is continued risk of transfusion transmitted infections (TTIs) from newly emerging or re-emerging infections. Globally, several pathogen reduction technologies (PRTs) for blood safety have been in development as an alternative to traditional treatment methods. Despite broad spectrum antimicrobial efficacy, some of the approved ultraviolet (UV) light-based PRTs, understandably due to UV light-associated toxicities, fall short in preserving the full functional spectrum of the treated blood components. As a safer alternative to the UV-based microbicidal technologies, investigations into the use of violet-blue light in the region of 405 nm have been on the rise as these wavelengths do not impair the treated product at doses that demonstrate microbicidal activity. Recently, we have demonstrated that a 405 nm violet-blue light dose of 270 J/cm2 was sufficient for reducing bacteria and the parasite in plasma and platelets suspended in plasma while preserving the quality of the treated blood product stored for transfusion. Drawn from the previous experience, here we evaluated the virucidal potential of 405 nm violet-blue light dose of 270 J/cm2 on an important blood-borne enveloped virus, the human immunodeficiency virus 1 (HIV-1), in human plasma. Both test plasma (HIV-1 spiked and treated with various doses of 405 nm light) and control plasma (HIV-1 spiked, but not treated with the light) samples were cultured with HIV-1 permissive H9 cell line for up to 21 days to estimate the viral titers. Quantitative HIV-1 p24 antigen (HIV-1 p24) levels reflective of HIV-1 titers were measured for each light dose to assess virus infectivity. Our results demonstrate that a 405 nm light dose of 270 J/cm2 is also capable of 4–5 log HIV-1 reduction in plasma under the conditions tested. Overall, this study provides the first proof-of-concept that 405 nm violet-blue light successfully inactivates HIV-1 present in human plasma, thereby demonstrating its potential towards being an effective PRT for this blood component safety.

Human immunodeficiency virus p24 antigen and antibody, herpes simplex virus-2 IgM and tumor necrosis factor alpha plasma levels in adult female children living in single-parent households: a case-control observational study

Abstract Objective: Human immunodeficiency virus (HIV) p24 antigen and antibody and herpes simplex virus 2 IgM are seromarkers indicating infection with HIV and herpes simplex virus-2 (HSV-2), respectively, whereas tumor necrosis factor α is an inflammatory biomarker that can be triggered by infections. Female children of single parents are faced with many socio-economic challenges that make them vulnerable to sexual influences and prone to sexually transmitted infections. The goal of this work was to determine HIV p24 antigen/antibody, HSV-2 IgM and tumor necrosis factor-α plasma levels in adult female children living in single-parent households. Methods: In this case-control observational study, 100 adult female children living with a single parent (50 living with a single mother and 50 living with a single father; age: 18–22 years) and 100 age-matched women living with both parents were recruited to serve as the test and control groups, respectively. All subjects were negative for acid-fast bacilli, plasmodium, hepatitis C virus, and hepatitis B virus. Human tumor necrosis factor α, HSV-2 IgM, antibody to hepatitis C virus, hepatitis B surface antigen and human immunodeficiency virus p24 antigen and antibody (HIV p24 Ag/Ab) levels were determined by ELISA, while the detection of acid-fast bacilli in sputum and Plasmodium in blood was carried out by optical microscopy. This work was carried out in the Owo/Ose Federal Constituency in Ondo State that shares boundaries with Edo State. The study protocol was approved by the Research and Ethical Committee of the Department of Medical Laboratory Science, Achievers University, Owo, Nigeria (AUO/MLS/2020/127) on August 27, 2020. Results: HIV p24 Ag/Ab was detected in 0 adult female children living with a single mother, 1 (2%) adult female child living with a single father and 1 (1%) adult female child living with both parents. HSV-2 IgM was detected in 9 (18%) adult female children living with a single mother, 13 (26%) adult female children living with a single father, and 5 (10%) adult female children living with both parents. Conclusion: This work shows that adult female children of single parents are vulnerable to sexual influences, and thereby more prone to HSV-2 and possibly HIV, especially adult female children of single fathers.

A triple-layer microchannel array chip with micro through-holes for smartphone based point-of-care testing of biomarker

Colorimetric detection on a microchip frequently suffers the sensitivity problem due to the limited optical path length. Herein, a point-of-care testing (POCT) device based on the colorimetric detection on a microchip with an array of micro through holes for enlarged optical length and an optical imaging system was demonstrated. Each micro through hole has a depth of 2 mm and a volume roughly 0.6 μl, connecting to a microchannel for the efficient reaction. Up to 32 micro through holes were arranged compactly along a round region with a diameter of 13 mm to make them effectively captured by a smartphone camera in a short distance (6.5 cm). For reliable smartphone imaging, a handheld, battery powered optical imaging cassette was made by three-dimensional (3D) printing. A data processing program was also written to realize the detection area selection, RGB (red, green, blue) value reading and detection signal calculation. With the integrated device, a biomarker, human immunodeficiency virus (HIV) p24 antigen in human serum was detected down to 20 pg/ml, much better than that with microchannels. The proposed microchip and the imaging system can be a promising POCT or on-site detection tool based on colorimetric detection.

Donation testing and transfusion transmissible infections

Donation testing and transfusion transmissible infections

Quality assuring HIV point of care testing using whole blood samples

The Royal College of Pathologists Australasia Quality Assurance Programs (RCPAQAP), have offered dedicated external quality assurance (EQA) for HIV point of care testing (PoCT) since 2011. Prior to this, EQA for these tests was available within the comprehensive human immunodeficiency virus (HIV) module. EQA testing for HIV has typically involved the supply of serum or plasma, while in the clinic or community based settings HIV PoCT is generally performed using whole blood obtained by capillary finger-stick collection. RCPAQAP has offered EQA for HIV PoCT using stabilised whole blood since 2014. A total of eight surveys have been undertaken over a period of 2 years from 2014 to 2015. Of the 962 responses received, the overall consensus rate was found to be 98% (941/962). A total of 21 errors were detected. The majority of errors were attributable to false reactive HIV p24 antigen results (9/21, 43%), followed by false reactive HIV antibody results (8/21, 38%). There were 4/21 (19%) false negative HIV antibody results and no false negative HIV p24 antigen results reported. Overall performance was observed to vary minimally between surveys, from a low of 94% up to 99% concordant. Encouraging levels of testing proficiency for HIV PoCT are indicated by these data, but they also confirm the need for HIV PoCT sites to participate in external quality assurance programs to ensure the ongoing provision of high quality patient care.

A Microfluidic Paper‐Based Origami Nanobiosensor for Label‐Free, Ultrasensitive Immunoassays

Microfluidic paper-based analytical devices (μPADs) represent a promising platform technology for point-of-care diagnosis. Highly sensitive, rapid, and easy-to-perform immunoassays implemented on μPADs are desirable to fulfill the promise of the μPAD technology. This article reports the first microfluidic paper-based origami nanobiosensor (origami μPAD), which integrates zinc oxide nanowires (ZnO NWs) and electrochemical impedance spectroscopy (EIS) biosensing mechanism, for label-free, ultrasensitive immunoassays. The EIS mechanism features simple and label-free assay operations which take less than 25 min to be finished, while the ZnO NWs allow covalent bonding for immobilizing probe proteins and improve the biosensing performance with such features as high surface-area-to-volume ratios and high sensitivity to surface binding. The calibration of the device reveals an ultralow limit of detection (LOD) of 60 fg mL(-1) (>100 times lower than those of existing μPADs) for rabbit immunoglobulin G in phosphate-buffered saline. The detection of human immunodeficiency virus p24 antigen in human serum with a low LOD of 300 fg mL(-1) (>33 times lower than that of a commercial p24 antigen test kit) is also demonstrated. This novel μPAD design offers ultrahigh sensitivity, short assay time, and ease of operation, and thus possesses significant potential for low-cost, rapid molecular diagnosis of early-stage diseases.

A study on patterns of co-infections among blood donors at the blood bank of a tertiary care referral teaching hospital in South India

Background: Blood serves as a vehicle for transmission of blood-borne pathogens including human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), malaria parasite (MP) and syphilis. Safe blood and blood products should be transfused to all patients in need for blood transfusion. Material and Methods: All blood donors attending to the blood bank during the period January 2009 to December 2014 were screened for hepatitis B surface antigen (HBsAg), anti HCV antibody, anti HIV-1, 2 antibodies and HIV p24 antigen by using the appropriate enzyme-linked immunosorbent assay (ELISA) method and further confirmed using an ELISA kit from a different manufacturer. Malarial antigen testing was done by rapid diagnostic device, which is based on immunochromatographic technique. The rapid plasma reagin (RPR) test was used for estimation of syphilis infection and further confirmed by Treponema pallidum haemagglutination assay (TPHA). Results: Of the 41,785 donors who were screened during the study period, 20 (0.05%) were reactive for different combination of infections. The various combination of infections seen were as follows; HBV+HCV and HBV+HIV (6/20) each, HIV+HCV (3/20), HIV + syphilis (2/20) and HBV+HIV+HCV, HBV+MP, HBV+syphilis (1/20 each); and HIV+Syphilis constituted for 10% (2/20). Conclusion: A properly conducted donor screening, notification and counseling of permanently deferred donors will help in reducing these co-infection rates.

Costs per Diagnosis of Acute HIV Infection in Community-based Screening Strategies: A Comparative Analysis of Four Screening Algorithms.

In nonhealthcare settings, widespread screening for acute human immunodeficiency virus (HIV) infection (AHI) is limited by cost and decision algorithms to better prioritize use of resources. Comparative cost analyses for available strategies are lacking. To determine cost-effectiveness of community-based testing strategies, we evaluated annual costs of 3 algorithms that detect AHI based on HIV nucleic acid amplification testing (EarlyTest algorithm) or on HIV p24 antigen (Ag) detection via Architect (Architect algorithm) or Determine (Determine algorithm) as well as 1 algorithm that relies on HIV antibody testing alone (Antibody algorithm). The cost model used data on men who have sex with men (MSM) undergoing community-based AHI screening in San Diego, California. Incremental cost-effectiveness ratios (ICERs) per diagnosis of AHI were calculated for programs with HIV prevalence rates between 0.1% and 2.9%. Among MSM in San Diego, EarlyTest was cost-savings (ie, ICERs per AHI diagnosis less than $13.000) when compared with the 3 other algorithms. Cost analyses relative to regional HIV prevalence showed that EarlyTest was cost-effective (ie, ICERs less than $69.547) for similar populations of MSM with an HIV prevalence rate >0.4%; Architect was the second best alternative for HIV prevalence rates >0.6%. Identification of AHI by the dual EarlyTest screening algorithm is likely to be cost-effective not only among at-risk MSM in San Diego but also among similar populations of MSM with HIV prevalence rates >0.4%.

Screening and confirmatory testing strategies for the major transfusion‐transmissible viral infections

BackgroundTesting donated blood for human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and human T‐cell lymphotropic virus (HTLV) is important as all are transfusion‐transmissible viral infections (TTVIs). A particular challenge in donor screening for TTVIs is that donor selection seeks to minimize the prevalence of TTVIs which in the context of testing substantially increases the likelihood that reactive test results represent ‘false’ rather than ‘true’ reactivity. To address this donor testing algorithms seek to combine strategies to optimize both sensitivity (optimal detection of the ‘target’ pathogen) and specificity (minimising ‘false’ reactivity)AimsFirst, review the fundamental principles underpinning TTVI screening and confirmatory algorithms and discuss key challenges. Second, using working examples illustrate how sound design can lead to optimal, cost‐effective solutions.Materials and MethodsScreening algorithms vary dependent on a number of factors including the epidemiology of the TTVI in the donor population and the available resources (e.g. funding, automation level, technical skill). TTVI screening tests include rapid tests (RT), immunoassays (IA) and nucleic acid tests (NAT). RTs and IAs target ‘serological’ markers of infection (anti‐HIV, HIV p24 antigen, anti‐HCV, HBsAg, anti‐HBc or anti‐HTLV) whereas NAT targets viral RNA (HCV and HIV) or DNA (HBV). NAT has the advantage of earlier detection because viral RNA/DNA appears in the bloodstream before serological markers. However NAT is comparatively expensive requiring higher levels of automation and more skilled staff. Confirmatory testing seeks to ‘confirm’ the presence of the pathogen of interest optimizing donor counselling and referral. The appropriate confirmatory strategy will be dependent primarily on the screening strategy and available resourcing.ResultsWhile optimal screening strategies for HIV, HCV and HBV generally include NAT for its superior ability to identify donors with early infection, there are alternative strategies which can provide almost equivalent safety. For example, the use of HIV and HCV ‘combo’ IAs which combine antibody with antigen (HIV p24Ag or HCV Ag) detection significantly improve sensitivity for early infection. In resource poor settings RT for HIV, HCV and to a lesser extent HBV can still provide a high level of safety particularly where carefully selected. Repeating samples reactive on a primary screening test on a second screening test (termed a ‘sequential immunoassay’ or SI algorithm) and assigning a final status based on concordant reactivity has been shown to improve effectiveness although is dependent on judicious test selection. For HIV, HCV and HTLV antibody based screening strategies immunoblots are often used to confirm the presence of antibody. However, immunoblots are relatively costly and can have poor specificity making it important to optimise the specificity of the screening algorithm. Immunoblotting subsequent to a sequential immunoassay approach has been shown to improve the efficiency and effectiveness of the strategy. Since NAT for HIV, HCV and HBV have demonstrated very high specificity, they now form an independent method of confirming infection for serology reactive samples. In some countries, samples concordantly reactive on serology and NAT screening tests are considered ‘confirmed’ without the need for immunoblotting.ConclusionsEven in resource constrained settings optimally designed screening and confirmatory strategies can significantly reduce the risk of transfusion‐transmissible viral infection.

Dengue Virus Serotype 1 Non-Structural Protein NS5 Expression Interferes with HIV Replication in a CD4+ T-Cell Line

The NS5 protein expression of certain flaviviruses, such as Dengue virus type 2, West Nile virus, Hepatitis C virus, and GB virus type C, is associated with a reduced in vitro human immunodeficiency virus (HIV) viral load. To evaluate the suppression effect of the dengue virus serotype 1 (DENV1) NS5 protein on HIV replication, a CD4+ T-cell line was transfected with a plasmid that contained the coding sequence of the DENV1 NS5 gene, and later, it was infected with HIV. DENV1 NS5 protein expression suppressed HIV replication by 28.88% (P < 0.005) on the fifth day compared with the control cells. These results confirm the suppression effect on HIV replication when the DENV1 NS5 protein is expressed in CD4+ T cells. Additional studies are needed to understand exactly how the DENV1 NS5 protein participates in the inhibition of HIV in vitro. HIV interaction with other infectious agents, especially in tropical regions, is associated with accelerated HIV/acquired immunodeficiency syndrome (AIDS) disease progression. However, Watt and others1 reported that HIV and dengue interaction was associated with a reduced HIV viral load. In regard to this finding, there are only four reports on HIV and DENV interaction in humans. The first study refers to an HIV patient infected with DENV1, in which a reduction in the viral load was observed during the coinfection.1 The second study describes an HIV patient with dengue hemorrhagic fever in Brazil,2 and the third report is a case series that includes five HIV patients infected with dengue in Singapore.3 Finally, a DENV3 and HIV coinfection in Cuba was described.4 Previous in vitro studies have reported that NS5 protein expression in certain flaviviruses, including DENV2, West Nile virus, Hepatitis C virus, Yellow Fever virus, and GB virus type C(GBV-C), is associated with HIV replication suppression in CD4+ T cells, which is attributed to an increase in the stromal cell-derived factor-1 (SDF-1) cytokine level expression.5 SDF-1 is the principle ligand for the CXCR4 coreceptor, and it blocks HIV fusion and entry into the CD4+ T lymphocytes.6 Despite the fact that these studies have suggested that the NS5 protein expression of DENV2 and other flaviviruses is associated with elevated levels of SDF-1 expression, the participation of the NS5 polyprotein during HIV suppression is not clear. The present study evaluated the effect of DENV1 NS5 protein expression on HIV replication in a CD4+ T-cell line. An in vitro study was carried out, in which Jurkat CD4+ T-cell cultures were infected with HIV. A DENV1 NS5 gene coding sequence was introduced into the experimental group, whereas the control group was only infected with HIV. HIV p24 antigen levels were measured as a viral replication estimator at the end of the experiment.

An Ultrasensitive Electrochemical Immunosensor for HIV p24 Based on Fe₃O₄@SiO₂ Nanomagnetic Probes and Nanogold Colloid-Labeled Enzyme-Antibody Copolymer as Signal Tag.

An ultrasensitive portable electrochemical immunosensor for human immunodeficiency virus p24 (HIV p24) antigen detection has been developed, whereby the detection sensitivity was 1000 times higher than that of the ELISA method. Firstly, a novel HRP enzyme–antibody copolymer (EV-p24 Ab2) was synthesized through an EnVision regent (EV, a dextrin amine skeleton anchoring more than 100 molecules of HRP and 15 molecules of anti IgG), then incubated in the secondary antibody of p24. Secondly, the copolymer was immobilized on the gold nanocolloids (AuNPs) to fabricate a novel signal tag (AuNPs/EV-p24 Ab2). Subsequently, a sandwich-type immunoreaction would take place between the capture probe (silicon dioxide-coated magnetic Fe3O4 nanoparticles (MNPs) labeled with the primary p24 antibody (MNPs-p24 Ab1)), p24 (different concentrations) and the signal tag [AuNPs/EV-p24 Ab2)] to form the immunocomplex. Finally, the immunocomplex was absorbed on the surface of screen printed carbon electrode (SPCE) by a magnet and immersed in the o-hydroxyl phenol (HQ) and H2O2. The large amounts of HRP on the signal tag can catalyze the oxidation of HQ by H2O2, which can induce an amplified reductive current. Moreover, the capture probe could improve the accumulation ability of p24 and facilitate its separation from the substrate through the magnet. Under optimal conditions, the proposed immunoassay exhibited good sensitivity to p24 within a certain concentration range from 0.001 to 10.00 ng/mL, with a detection limit of 0.5 pg/mL (S/N = 3). The proposed method can be used for real-time and early detection of HIV-infected people.

Performances of four fourth‐generation human immunodeficiency virus‐1 screening assays

Fourth-generation human immunodeficiency virus-1 (HIV-1) screening assays have improved sensitivity, but vary in performance characteristics. The purpose of this study was to evaluate four different fourth-generation HIV-1 assays. These assays included the AxSYM HIV Ag/Ab Combo (Abbott diagnostics, Delkenheim, Germany), ARCHITECT HIV Ag/Ab Combo (Abbott), Elecsys 2010 HIV Combi (Roche Diagnostics GmbH, Mannheim, Germany), and Elecsys HIV Combi PT (Roche). A total of 1,306 samples that included 1,225 clinical samples and 81 samples consisting of seroconversion panels, an HIV-1 p24 antigen sensitivity panel, and dilution series of HIV-1 lysates and HIV-1 antibodies were tested. All of the assays had sensitivities of 100% on clinical samples. The specificities of the AxSYM, ARCHITECT, Elecsys 2010 HIV Combi, and Elecsys HIV Combi PT were 99.6, 99.6, 99.0, and 99.5%, respectively. Of the 81 samples with different levels of HIV antigen or antibody and/or subtypes, Elecsys HIV Combi PT and ARCHITECT HIV Ag/Ab Combo showed better analytical sensitivities than the other two assays. In summary, the performance characteristics of AxSYM, ARCHITECT, and Elecsys HIV Combi PT were comparable and satisfactory for clinical samples. ARCHITECT HIV Ag/Ab Combo and Elecsys HIV Combi PT have the higher analytical sensitivities, and would be preferable for reducing the window period.

Point-of-Care Diagnostics for Acute HIV Infection: An Important Public Health Priority

To the Editor—We appreciate the correspondence in this issue of the Journal by Jones et al and Laperche et al evaluating the performance of the Alere Determine HIV-1/2 Ag/Ab Combo test (Combo point-of-care test [POCT]) for the detection of antibodies for established human immunodeficiency virus (HIV) infection and p24 antigen for acute HIV infection (AHI) [1, 2]. We believe that the earliest stages of HIV infection, including AHI, are critical for both individual health and HIV prevention. During AHI, establishment of latency currently renders HIV infection incurable. Persons with AHI also have high viral loads, making them highly contagious for a brief period. AHI therefore represents an important time for intervention [3]. Identification of subjects with AHI is critical, yet challenging. Since persons are antibody-negative during AHI, HIV rapid tests, which detect HIV antibodies, cannot detect AHI. AHI can be detected only with diagnostics capable of identifying HIV RNA, DNA or p24 antigen. To date, most of these diagnostics have been laboratory-based. In a recent issue of the Journal, we evaluated the Combo POCT, a test designed to concomitantly detect HIV antibodies and p24 antigen in separate reading frames at the point of care [4]. Our study was conducted among persons attending a sexually transmitted infection clinic and an HIV testing and counseling center in Lilongwe, Malawi. We found that the antibody portion of the test had excellent sensitivity and specificity for detecting established HIV infection. However, the antigen portion of the test had zero sensitivity and inadequate specificity for detecting AHI. The antigen portion of the test was unable to identify any of the 8 persons with true AHI, and it falsely classified 6 HIV-uninfected persons as having AHI. Such incorrect results could cause considerable mental anguish, confusion, and cost. Jones et al report similar findings among high-risk persons in the United Kingdom [1]. The antibody portion of the Combo POCT had excellent sensitivity and specificity, but the antigen portion of the test had poor sensitivity and specificity. It did not identify the 2 persons with AHI, and it incorrectly classified 2 HIV-uninfected and 1 antibody-positive person as having AHI. They also noted several invalid tests and implementation challenges owing to a narrow reading interval. Laperche et al assess the sensitivity of the Combo POCT at different p24 concentrations and among different clades in archived plasma and stored supernatants [2]. Even in these laboratory settings, the Combo POCT was unable to detect p24 consistently, especially with non-B subtypes. Although laboratory testing can be an important early step for gauging when a test may or may not perform adequately, it simply cannot replace field testing, which is required to determine ultimate utility. This is especially important for a test like the Combo POCT, which is designed to be used at the point of care on finger-stick whole blood. Laperche et al note the difficulty of field testing for AHI. However, we and others have demonstrated the feasibility of this approach. We have reported elsewhere that AHI can be detected routinely in the sexually transmitted infection setting where we conducted our analysis [5], allowing us to conduct ongoing studies related to this stage of HIV disease [6–7]. Although the performance of the antigen portion of the Combo POCT has been disappointing, the goal of identifying persons during AHI is important [8]. Investigators and industry should work together toward designing sensitive and specific diagnostics that can detect AHI at the point of care. These diagnostics must then be field tested before clinical use, regardless of the degree of difficulty involved.

Cost-effectiveness of a Fourth-Generation Combination Immunoassay for Human Immunodeficiency Virus (HIV) Antibody and p24 Antigen for the Detection of HIV Infections in the United States

Purpose: The US Food and Drug Administration recently approved the first 4th-generation HIV test. This study evaluated the cost-effectiveness of the 4th-generation assay versus a 3rd-generation test in screening for HIV infections in the United States. Methods: An exploratory microsimulation model was developed that follows hypothetical individuals and simulates the course of HIV/AIDS, treatment with highly active antiretroviral therapy, and transmissions. Results: With a 1% HIV prevalence, screening 1.5 million individuals with the 4th- versus 3rd-generation assay resulted in detection of 266 additional HIV cases at an incremental cost per additional HIV case detected of $63,763, an additional 489 life years and 395 quality-adjusted life years (QALYs), and 26 HIV transmissions prevented. Although lifetime costs were increased by $33.6 million, the incremental cost/QALY gained was $85,206. The 4th-generation test was more cost-effective in high incidence settings. The number needed to screen to detect one additional HIV case was 5,635. Conclusions: Screening using the 4th-generation assay may be cost-effective for HIV detection in appropriate settings, resulting in increased case identification, fewer transmissions, extended life, and increased quality of life. With early and accurate detection, this 4th-generation test may provide a suitable alternative to current 3rd-generation tests.

Cost-effectiveness of a Fourth-Generation Combination Immunoassay for Human Immunodeficiency Virus (HIV) Antibody and p24 Antigen for the Detection of HIV Infections in the United States

The US Food and Drug Administration recently approved the first 4th-generation HIV test. This study evaluated the cost-effectiveness of the 4th-generation assay versus a 3rd-generation test in screening for HIV infections in the United States. An exploratory microsimulation model was developed that follows hypothetical individuals and simulates the course of HIV/AIDS, treatment with highly active antiretroviral therapy, and transmissions. With a 1% HIV prevalence, screening 1.5 million individuals with the 4th- versus 3rd-generation assay resulted in detection of 266 additional HIV cases at an incremental cost per additional HIV case detected of $63,763, an additional 489 life years and 395 quality-adjusted life years (QALYs), and 26 HIV transmissions prevented. Although lifetime costs were increased by $33.6 million, the incremental cost/QALY gained was $85,206. The 4th-generation test was more cost-effective in high incidence settings. The number needed to screen to detect one additional HIV case was 5,635. Screening using the 4th-generation assay may be cost-effective for HIV detection in appropriate settings, resulting in increased case identification, fewer transmissions, extended life, and increased quality of life. With early and accurate detection, this 4th-generation test may provide a suitable alternative to current 3rd-generation tests.

Establishment of novel cell lines latently infected with human immunodeficiency virus 1

Many human immunodeficiency virus 1 (HIV-1) researchers focus on the developing new anti-reservoir therapy to eradicate HIV-1 provirus from the HIV-1-infected patients. HIV-1 provirus is the major obstacle for effective HIV-1 treatment because it integrates into the host genome and can produce a virus progeny after stopping highly active antiretroviral therapy (HAART). We established two novel cell lines latently infected with HIV-1 by limiting dilution cloning of A3.01 cells infected with HIV-1. Analysis of the flanking sequence of HIV-1 proviral DNA integrated into chromosomal cellular DNA revealed that proviral DNA was inserted into different sites of different chromosomes in the two examined cell lines. In these lines, virus reactivation could be induced by a phorbol 12-myristate 13-acetate (PMA) treatment that resulted in a marked increase of the production HIV-1 p24 antigen and appearance of the infectious virus. The novel cell lines latently infected with HIV-1 represent further tool for the study of molecular mechanisms of viral latency and development of anti-reservoir therapy of HIV-1 infection.

A Non-enzyme Amperometric Immunosensor for Rapid Determination of Human Immunodeficiency Virus p24 Based on Magnetism Controlled Carbon Nanotubes Modified Printed Electrode

Abstract A magnetism-controlled, disposable amperometric immunosensor was fabricated for the determination of human immunodeficiency virus p24 antigen. First, Fe3O4 (core)/Au (shell) nanoparticle [gold magnetic particle (GMP)]-coated multiwalled carbon nanotubes (MWCNT-GMP) were prepared. Then, monoclonal antibody (anti-p24) was immobilized on MWCNT-GMP to prepare MWCNT-GMP/anti-p24 composite magnetic particles. At last, MWCNT-GMP/anti-p24 was adsorbed on the surface of N,N'-bis-(2-hydroxy-methylene)-o-phenylenediamine copper (CuRb)-modified, screen-printed carbon electrodes through external magnetic field. Cyclic voltammetry and differential pulse voltammetry (DPV) were used to study the electrochemical properties of the modified electrode. The amount of p24 in the serum sample of patients with AIDS was determined by one-step immunoassay. When different concentrations of p24 were added into 25 μL of phosphate-buffered solution (pH 7.0) containing 1.0 μM H2O2, the percentage of DPV cathodic peak current decrease (CR, %) exhibited a linear relationship with the concentration of p24 in the range of 0.6-160 μg L−1. The detection limit was 0.32 μg L−1 (3σ). The immunosensor was used to determine p24 in serum samples of patients with AIDS, and the results were consistent with those of the traditional ELISA method. The proposed amperometric immunosensor was sensitive, rapid, magnetic field-controlled, and disposable; therefore, it could be used to determine even traces of p24 in the blood serums of patients with AIDS.

Assessment of the Ability of a Fourth-Generation Immunoassay for Human Immunodeficiency Virus (HIV) Antibody and p24 Antigen To Detect both Acute and Recent HIV Infections in a High-Risk Setting

An immunoassay (IA) that simultaneously detects both antibody to human immunodeficiency virus (HIV) and HIV p24 antigen (Architect HIV Ag/Ab Combo) was evaluated for its ability to detect HIV infection by using a panel of specimens collected from individuals recently infected with HIV type 1 (HIV-1). This IA was found to be capable of detecting the majority (89%) of infections, including 80% of those considered acute infections based on the presence of HIV RNA and the lack of detectable antibody to HIV. Substantial improvements in detection of recent infections by the Architect HIV Ag/Ab Combo relative to previous generations of IAs as well as the capacity to detect acute infections have important implications for HIV prevention strategies.