Incomplete HIV type 1 antibody evolution and seroreversion in acutely infected individuals treated with early antiretroviral therapy

Detection of unreported usage of the antiretroviral drug lamivudine in two blood donors

BACKGROUND

Unreported HIV antiretroviral (ARV) drug usage by blood donors compromises the ability to detect evidence of HIV infection in blood screening tests and represents a risk for blood transfusion safety. Our objective was to determine the frequency of undeclared ARV drug use by blood donors with altered HIV markers.

STUDY DESIGN AND METHODS

This was a retrospective cross-sectional analysis of donations that were tested for HIV antibody (ab), antigen (ag), and RNA by chemiluminescent immunoassay and nucleic acid screening tests. Positive samples were retested and were subjected to ARV drug testing by high-performance liquid chromatography-tandem mass spectrometry.

RESULTS

Of 345,252 blood donations, 361 (0.1%) were positive on initial testing. Samples from 296 (81.9%) of these donations were available for further analysis. The presence of HIV ab/ag and/or RNA was confirmed in 83 (28.0%) of these samples. All 296 bloods were subjected to ARV testing. The ARV drug lamivudine, at 11.3 and 6.7 ng/mL, was detected in 2 of 83 (2.4%) donations that were HIV positive. Other drugs were not detected.

CONCLUSION

Unreported ARV usage was identified in two candidates for blood donation. More intensive efforts to educate donors about disclosure and to investigate the extent of this phenomenon in Brazil are needed.

Can newborn infants with positive HIV soon after birth be diagnosed with intrauterine infection?

BACKGROUND

Mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV) can occur intrauterine, intrapartum, and postpartum. Currently, infants with confirmed positive results in virological tests before 48 h of age are defined as having intrauterine infection.

AIM

We herein review the literature that identifies emerging challenges in diagnosing intrauterine HIV infection to rethink the current diagnostic criteria.

FINDINGS

A number of reports have shown that some infants who were diagnosed with intrauterine HIV infection after birth became negative for HIV in the subsequent follow-ups, including negative HIV antibodies at the age of 12-18 months. Such "clearance" of HIV was attributed to various reasons: neonatal antiretroviral treatment (ART), false positivity, strong host immune response, or unknown factors in maternal breast milk.

DISCUSSIONS

Positive HIV tests in newborn infants shortly after birth do not necessarily indicate HIV infection, because maternal HIV can enter fetal circulation intrapartum due to the repetitive, strong uterine contractions. The infants are therefore exposed to, but may not yet be infected with HIV at that time. The current diagnostic criteria cannot differentiate HIV exposure from HIV infection, leading to so-called "challenges in diagnosing intrauterine HIV infection". Those infants diagnosed with intrauterine infection who cleared HIV later were less likely to have been truly infected with HIV, but more likely to have been exposed to HIV. Moreover, we suggest that the determination of HIV antibody titers in infants' serial serum samples can provide valuable information to distinguish intrapartum exposure from intrauterine infection.

A Longitudinal Cohort Study of Risk Factors Associated with Small Ruminant Lentivirus Seropositivity in Intensively Reared Dairy Ewes in Greece

A two-year longitudinal cohort study was conducted on a total of 407 purebred Chios and Lacaune ewes from four intensive dairy sheep farms to assess potential risk factors for small ruminant lentiviruses (SRLVs) seropositivity. Ewes were serologically tested semiannually at pre-mating and pre-lambing, and their age, breed, and body condition score (BCS) were recorded. Εwes were categorized as constantly seronegative, constantly seropositive, seroconverted, seroreverted, or animals with an intermittent presence of antibodies. Mixed binary logistic regression models were used to estimate the adjusted relative risks of the studied risk factors for (i) the individual ewes' seropositivity, (ii) the manifestation of specific serological patterns, and (iii) the occurrence of seroconversion and seroreversion incidents. Increased age was associated with seropositivity and constantly seropositive status (p < 0.001 in both cases). On the other hand, age was negatively associated with constantly seronegative pattern, seroconversion incident, and the intermittent presence of antibodies (p < 0.05 in all cases). Moreover, breed was recognized as a risk factor: Lacaune ewes demonstrated increased seropositivity, whereas Chios ewes were more likely to demonstrate an intermittent presence of antibodies (p < 0.01 in both cases). Seropositive status (p < 0.001), seropositivity in animals with an intermittent presence of antibodies (p = 0.001), and seroconversion incidents (p < 0.001) were significantly increased at pre-lambing compared to pre-mating. The risk factors recognized in our study contribute to a better understanding of SRLVs epidemiology and the evidence-based designation of SRLVs' control programs in intensive dairy sheep farms in Greece.

Seroepidemiology of Maedi-Visna in Intensively Reared Dairy Sheep: A Two-Year Prospective Study

The objective of this study is to prospectively evaluate the seroepidemiology of maedi-visna (MV) infections in intensively reared dairy sheep. A total of 407 purebred Chios and Lacaune ewes from four farms were surveyed for two consecutive years and were serologically tested semiannually with an indirect ELISA at pre-mating and pre-lambing. The farms' structure and management practices were similar and animal traits (age, breed, and production stage) were recorded. Based on the serological status, morbidity frequency measures were estimated, and ewes were categorized as constantly seronegative, constantly seropositive, seroconverted, seroreverted, or as animals with an intermittent presence of antibodies. During the study, period seroprevalence, incidence rate, and cumulative incidence were 84.8%, 33.6 new cases per 100 sheep-semesters, and 64.2%. Point-seroprevalence ranged from 48.5% to 96.0% among the studied farms and sampling occasions, and they increased by age. Increased morbidity frequency measures indicate the significance of horizontal transmission in intensive dairy sheep farms. A remarkable percentage of infected animals seroreverted (8.1%) or presented an intermittent presence of antibodies (10.3%) during the study, confirming the risk of misdiagnosis in cross-sectional studies and in the currently implemented testing and elimination programs. The serological patterns observed in our study need to be considered when studying MV epidemiology and for the designing of efficient MV elimination programs.

Taking a step back from testing: Preanalytical considerations in molecular infectious disease diagnostics

Recent studies evaluating the preanalytical factors that impact the outcome of nucleic-acid based methods for the confirmation of SARS-CoV-2 have illuminated the importance of identifying variables that promoted accurate testing, while using scarce resources efficiently. The majority of laboratory errors occur in the preanalytical phase. While there are many resources identifying and describing mechanisms for main laboratory testing on automated platforms, there are fewer comprehensive resources for understanding important preanalytical and environmental factors that affect accurate molecular diagnostic testing of infectious diseases. This review identifies evidence-based factors that have been documented to impact the outcome of nucleic acid-based molecular techniques for the diagnosis of infectious diseases.

Seroconversion, seroreversion, and serowaffling among participants initiating antiretroviral therapy in Project DETECT

BACKGROUND

Incomplete HIV seroconversion and seroreversion are increasingly documented by testing and pre-exposure prophylaxis programs more than previously recognized. This analysis reports on incomplete seroconversion and seroreversion by specimen and test type among Project DETECT participants.

METHODS

Project DETECT included a longitudinal study of point-of-care tests. Participants were categorized as having "incomplete seroconversion" if all timepoints had ≥1 nonreactive test at study censoring. Among participants with incomplete seroconversion, we defined "seroreversion" as sustained regression to nonreactive for any test following a reactive result. We define "serowaffling" as any reactive result followed by a nonreactive and then reactive result. We used Fisher's exact tests to explore relationships between Fiebig stage at ART initiation and incomplete seroconversion, seroreversion, and serowaffling.

RESULTS

Twenty of 1940 Project DETECT participants met criteria for this subset. Ten participants had complete seroconversion after a median of 23 (IQR 16-47) days following initial positive tests. Ten participants had incomplete seroconversion, eight of whom had seroreversion. Incomplete seroconversion with persistent nonreactive tests was seen only with oral fluid (OF). Of eight participants with seroreversion, all experienced seroreversion of OF tests if the test was ever reactive (n = 6); seroreversion occurred in fingerstick and venipuncture tests in two participants. Serowaffling occurred in nine (45%) participants. No associations were seen between Fiebig stage at ART start and complete seroconversion, seroregression, or serowaffling in our sample.

CONCLUSIONS

OF tests may be particularly susceptible to providing false-negative results. Seroreversion and incomplete seroconversion among individuals on antiretroviral treatment may represent a growing problem for HIV testing and treatment programs.

Transfusion-Acquired HIV: History, Evolution of Screening Tests, and Current Challenges of Unreported Antiretroviral Drug Use in Brazil

Prevention of HIV acquisition by blood transfusion from its emergence to the present day is reviewed, and current challenges are delineated. The experience of Fundação Pró-Sangue/Hemocentro de São Paulo, Brazil, is highlighted in the quest for improvements in blood safety and the evolution of increasingly sensitive and specific screening tests. Concerns and establishing stringent criteria in the screening of potential blood donors are emphasized, and the current criteria for identifying and deferring candidates at high risk of acquiring sexually transmitted diseases are summarized. Future challenges relate to the identification of donors with unreported use of antiretroviral drugs for prophylaxis against possible HIV exposure or for treatment of an HIV infection whose viral expression is undetectable by current analyses. There is a need to better understand the motivation of HIV-exposed donors and to educate them about the risk of transfusion-mediated HIV transmission despite having low or undetectable viral loads. In situations in which traditional HIV RNA or antibody detection assays remain negative, more sensitive analyses are needed to identify potential donors at risk for HIV transmission.

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.

Am I Positive? Improving HIV Testing in the Era of Pre-Exposure Prophylaxis (PrEP) and Immediate Anti-Retroviral Therapy (iART) using Machine Learning

Background

Human immunodeficiency virus (HIV) testing is the first step in the HIV prevention cascade. The Centers for Disease Control and Prevention HIV laboratory diagnostic testing algorithm was developed before preexposure prophylaxis (PrEP) and immediate antiretroviral therapy (iART) became standards of care. PrEP and iART have been shown to delay antibody development and affect the performance of screening HIV assays. Quantitative results from fourth-generation HIV testing may be helpful to disambiguate HIV testing.

Methods

We retrospectively reviewed 38 850 results obtained at an urban, academic medical center. We assessed signal-to-cutoff (s/co) distribution among positive and negative tests, in patients engaged and not engaged in an HIV prevention program, and evaluated changes in patients with multiple results. Classification and regression tree (CART) analysis was used to determine a threshold cutoff, and logistic regression was used to identify predictors of true positive tests.

Results

Ninety-seven percent of patients with a negative HIV test had a result that was ≤0.2 s/co. For patients tested more than once, we found differences in s/co values did not exceed 0.2 s/co for 99.2% of results. CART identified an s/co value, 38.78, that in logistic regression on a unique validation cohort remained associated with the likelihood of a true-positive HIV result (odds ratio, 2.49).

Conclusions

Machine-learning methods may be used to improve HIV screening by automating and improving interpretations, incorporating them into robust algorithms, and improving disease prediction. Further investigation is warranted to confirm if s/co values combined with a patient's risk profile will allow for better clinical decision making for individuals on PrEP or eligible for iART.

Influence of Combination Antiretroviral Therapy on HIV-1 Serological Responses and Their Implications: A Systematic Review and Meta-Analysis

We aimed to analyze HIV-1 seroreversion caused by combination antiretroviral therapy (cART) and to explore antibody levels of anti-HIV-1 as an alternative biomarker of HIV-1 reservoir. We searched PubMed, Embase, the Cochrane Library, and Web of Science up to August 2021 for publications about the performance of HIV-1 serological assays or the association between antibody responses against HIV-1 and HIV-1 reservoirs. Potential sources of heterogeneity were explored by meta-regression analysis, including the year of publication, country, pretreatment viral load, sample size, the timing of treatment, time on cART, and principle or type of serological assay. Twenty-eight eligible studies with a total population of 1,883 were included in the meta-analysis. The pooled frequency of HIV-1 seronegativity is 38.0% (95% CI: 28.0%–49.0%) among children with vertical HIV-1 infection and cART initiation at the age of less than 6 months, while the percentage of HIV-1 seronegativity declined to 1.0% (95% CI: 0%–3.0%) when cART was initiated at the age of >6 months. For adult patients, 16.0% (95% CI: 9.0%–24.0%) of them were serologically negative when cART was initiated at acute/early infection of HIV-1, but the seronegative reaction was rarely detected when cART was started at chronic HIV-1 infection. Substantial heterogeneity was observed among the studies to estimate the frequency of HIV-1 seronegativity in the early-cART population (I² ≥ 70%, p < 0.05 and all), while mild heterogeneity existed for the deferred-cART subjects. Moreover, anti-HIV-1 antibody response positively correlates with HIV-1 reservoir size with a pooled rho of 0.43 (95% CI: 0.28–0.55), suggesting that anti-HIV antibody level may be a feasible biomarker of HIV-1 reservoir size.

Helios expressing regulatory T cells are correlated with decreased IL-2 producing CD8 T cells and antibody diversity in Mozambican individuals living chronically with HIV-1

Background

Human immunodeficiency virus type 1 (HIV-1) causes impairment of T and B cell responses, which begins during the acute phase of infection and is not completely restored by antiretroviral treatment. Regulatory T cell (Tregs) can improve overall disease outcome by controlling chronic inflammation but may also suppress beneficial HIV-1 specific immune responses. We aimed to analyze the profile of Tregs and their correlation with the status of T cells activation, the expression of IL-2 and IFNγ and the profile of HIV-1 specific antibodies response in Mozambican people living chronically with HIV-1 (PLWH-C).

Results

In PLWH-C, the proportion of total Tregs was positively correlated with the proportion of IL-2⁺CD4 T cells (r = 0.647; p = 0.032) and IL-2⁺IFNγ⁺CD8 T cells (r = 0.551; p = 0.014), while the proportions of Helios⁺Tregs correlated inversely with levels of IL-2⁺CD8 T cells (r = − 0.541; p = 0.017). Overall, PLWH-C, with (82%) or without virologic suppression (64%), were seronegative for at least HIV-1 p31, gp160 or p24, and the breadth of antibody responses was positively correlated with proportions of CD38⁺HLA-DR⁺CD8 T cells (r = 0.620; p = 0.012), viral load (r = 0.452; p = 0.040) and inversely with absolute CD4 T cells count (r = − 0.481; p = 0.027). Analysis of all individuals living HIV-1 showed that the breadth of HIV-1 antibody responses was inversely correlated with the proportion of Helios⁺Tregs (r = − 0.45; p = 0.02).

Conclusion

Among Mozambican people living with HIV-1, seronegativity to some HIV-1 proteins is common, particularly in virologically suppressed individuals. Furthermore, lower diversity of HIV-specific antibodies is correlated to lower immune activation, lower viral replication and higher CD4 counts, in PLWH-C. Elevation in the proportion of Helios⁺Tregs is related to a reduction of CD8 T expressing intracellular IL-2, in PLWH-C, but may contribute to impairment of B cell function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-022-00487-3.

Influence of unreported HIV prophylaxis on the kinetics of post-blood donation HIV seroconversion

BACKGROUND

In 2020, of 110,000 blood donors screened for HIV exposure two individuals were identified who were viral RNA-positive but seronegative. One of the donors, borderline negative in a pooled screening test for HIV RNA, utilized antiretroviral drugs as post-exposure, pre-donation prophylaxis. The kinetics of subsequent HIV seropositivity in both donors are described.

STUDY DESIGN AND METHODS

Both donors were recalled and interviewed, and blood was obtained at intervals for HIV antibodies and RNA testing.

RESULTS

One donor used antiretroviral prophylaxis for 30 days due to a relationship with an HIV-positive partner. In follow-up samples, seroconversion was noted at 70 days, and viral RNA was detected at 105 days, after blood donation. In contrast, the other donor seroconverted in <25 days and the appearance and titer of HIV RNA was in accordance with the typical pre-seroconversion window.

CONCLUSION

The use of anti-viral prophylaxis by blood donors in the acute phase of HIV infection delays seroconversion. A 6-month deferral in blood donation after HIV prophylaxis, as currently recommended in Brazil, would have been sufficient in this case to mitigate the risk of transfusion-transmitted HIV. Ultimately, improvement in donor compliance with selection procedures for blood donation is needed to optimize blood safety.

Chronic and Early Antiretroviral Therapy Impact Human Immunodeficiency Virus (HIV) Serological Assay Sensitivity, Leading to More False-Negative Test Results in HIV Diagnosis

This retrospective study evaluated the reactivity of 3 human immunodeficiency virus (HIV) confirmatory assays (INNO-LIA, Geenius, and MP) and 7 HIV rapid tests on samples from 2 different study populations in Belgium. For the early-treated cohort (83 HIV-1 adult patients treated within 3 months after infection), HIV-1 diagnosis was not obtained in at least 1 confirmatory assay in 12.0% (10/83) and in an HIV rapid test in 31.3% (26/83). Confirmation assay sensitivities ranged from 87.5% to 95.2%, whereas rapid test assay sensitivities ranged from 75.9% to 100%. The time to treatment initiation or the length of time on treatment did not have a statistical influence on the probability to obtain a false-negative test result. The fastest reversion was demonstrated after 4 months of treatment. Among the long-term treated cohort (390 HIV-1 patients with ≥ 9 years of undetectable viral load), false-negative test results were found in at least 1 HIV confirmatory assay for 2.1% (8/390) of the patients and in a HIV rapid test for 4.9% (19/390). Confirmation assay sensitivities ranged from 98.1% to 99.5%, whereas rapid test sensitivities ranged from 96.2% to 100%. Longer treatment increased nonreactivity of the HIV rapid tests (P = .033). Undetectable viral load decreases the sensitivities of HIV diagnostic tests, and further monitoring of the performance of serological assays is advised.

Altered Antibody Responses in Persons Infected with HIV-1 While Using Preexposure Prophylaxis

Preexposure prophylaxis (PrEP) is an effective HIV prevention tool, although effectiveness is dependent upon adherence. It is important to characterize the impact of PrEP on HIV antibody responses in people who experience breakthrough infections to understand the potential impact on timely diagnosis and treatment. Longitudinal HIV-1-specific antibody responses were evaluated in 42 people who inject drugs (PWID) from the Bangkok Tenofovir Study (BTS) (placebo = 28; PrEP = 14) who acquired HIV while receiving PrEP. HIV-1 antibody levels and avidity to three envelope proteins (gp41, gp160, and gp120) were measured in the plasma using a customized Bio-Plex (Bio-Rad Laboratories, Hercules, CA) assay. A time-to-event analysis was performed for each biomarker to compare the distribution of times at which study subjects exceeded the recent/long-term assay threshold, comparing PrEP and placebo treatment groups. We fit mixed-effects models to identify longitudinal differences in antibody levels and avidity between groups. Overall, longitudinal antibody levels and avidity were notably lower in the PrEP breakthrough group compared to the placebo group. Time-to-event analyses demonstrated a difference in time to antibody reactivity between treatment groups for all Bio-Plex biomarkers. Longitudinal gp120 antibody levels within the PrEP breakthrough group were decreased compared to the placebo group. When accounting for PrEP adherence, both gp120 and gp160 antibody levels were lower in the PrEP breakthrough group compared to the placebo group. We demonstrate hindered envelope antibody maturation in PWID who became infected while receiving PrEP in the BTS, which has significant implications for HIV diagnosis. Delayed maturation of the antibody response to HIV may increase the time to detection for antibody-based tests. Clinical Trial Registration Number, NCT00119106.

Prolonged Posttreatment Virologic Control and Complete Seroreversion After Advanced Human Immunodeficiency Virus-1 Infection

Background

Possible human immunodeficiency virus (HIV)-1 clearance has rarely been reported. In this study, we describe a unique case of an HIV-positive, combination antiretroviral therapy (cART)-experienced woman with prior acquired immunodeficiency syndrome (AIDS) who has not experienced viral rebound for over 12 years since discontinuing cART.

Methods

Leukapheresis, colonoscopy, and lymph node excision were performed for detailed examination of virologic (including HIV reservoir) and immunologic features. Comparisons were made with chronically infected patients and healthy controls.

Results

No HIV-specific antibodies were detected in serum. Plasma HIV ribonucleic acid (RNA) levels were <0.2 copies/mL, and, except for low-frequency HIV deoxyribonucleic acid (DNA)⁺ cells in lymph node tissue (1 copy/3 × 10⁶ cells), HIV antigen could not be detected by quantitative virus outgrowth (<0.0025 infectious units/10⁶ CD4⁺ T cells) or by most measurements of HIV RNA or DNA in blood, lymph node, or gut-associated mononuclear cells. Human immunodeficiency virus-specific T-cell responses were detectable but low. Brain imaging revealed a prior biopsy site and persistent white matter disease since 1996. Human immunodeficiency virus DNA⁺ cells in the 1996 brain biopsy specimen confirmed her identity and initial HIV diagnosis.

Conclusions

This represents the first report of complete seroreversion, prolonged posttreatment virus suppression, a profoundly small HIV reservoir, and persistent HIV-specific T cells in an adult with prior AIDS.

HIV seronegativity in children, adolescents and young adults living with perinatally acquired HIV: A cross-sectional study in Thailand

INTRODUCTION

Early initiation of combination antiretroviral therapy (ART) with long-term viral suppression may lead to seronegativity in grown-up children with perinatally acquired HIV (PHIV). This study aimed to determine the frequency and associated factors of seronegativity in Thai children, adolescents and young adults with PHIV.

METHODS

A cross-sectional HIV serological study was performed in children, adolescents and young adults two years or older who were receiving ART with undetectable HIV-RNA for at least one year from August 2018 to August 2019. Medical records were extracted for multivariate analysis of independent factors for seronegativity.

RESULTS AND DISCUSSION

Of 110 patients, 50 male, median (range) age was 18.4 (4.8 to 26.6) years, 8 (7.3%) were seronegative, and 1 (0.9 %) was inconclusive. The seronegative group had a younger median (range) age at ART initiation: 3.0 (1.0 to 12.0) versus 40.0 (2.0 to 207.0) months, p = 0.045; and shorter median (range) duration from ART initiation to viral suppression: 16.8 (7.2 to 42.0) versus 55.2 (6.0 to 214.8) months, p = 0.036. Multivariate analysis identified younger age at ART initiation (aOR 0.69, 95% CI 0.49 to 0.98, p = 0.038) and shorter time to viral suppression after ART initiation (aOR 0.94, 95% CI 0.89 to 0.99, p = 0.019) as independent factors associated with HIV seronegativity. Of the infants who initiated ART < 3 and between three and six months of age, 50% and 26.7% became seronegative respectively.

CONCLUSIONS

HIV seronegativity was observed in children and adolescents with PHIV who initiated ART early in infancy and had rapid and sustained virological response. Awareness of this phenomenon will help avoid inappropriate treatment interruption on the basis of negative antibody testing.

Reduction of anti-HIV antibody responses in subjects receiving antiretroviral therapy during chronic HIV-1 infection

OBJECTIVE

Antiretroviral therapy (ART) can lead to a decline or absence of anti-HIV antibodies in HIV-infected children or acutely HIV-infected (AHI) subjects. However, the characteristics of anti-HIV antibody response in the subjects who are treated during chronic HIV-1 infection (CHI) have not yet been fully investigated.

METHODS

Different anti-HIV antibodies were longitudinally quantified and analyzed in 81 CHI adults under ART. The factors associated with antibody decline were evaluated by binary logistic regression analysis.

RESULTS

ART led to 36.0% (27/75) and 52.1% (38/73) of the patients whose anti-HIV levels reduced by more than 75% of the baseline levels at 12 and 24 months post-ART, respectively. The reduction of anti-HIV antibodies correlated with the decline of HIV-1 viral load with correlation coefficients in the range 0.556-0.848 or R2 value of 0.576-0.873 (P < 0.001). However, no negative detection of anti-HIV antibody was observed at 24 months post-ART. The time from HIV-1 diagnosis to ART initiation and the baseline anti-HIV levels were the key factors associated with quick decline of anti-HIV antibodies during ART.

CONCLUSIONS

ART-induced kinetics of anti-HIV antibody response was different among the subjects with AHI and CHI. Misdiagnosis of HIV-1 infection may not be a serious issue in HIV-1 chronically infected subjects under ART, and could ideally be avoided by using multiple HIV-1 antigens for screening purposes.

Efficacy of early antiretroviral therapy 36 hours after HIV infection in one blood donor

BACKGROUND

Discrepancies can occur with the use of clinical human immunodeficiency virus (HIV) diagnostic reagents for the HIV window period (WP; time from RNA to antibody detection by diagnostic or blood screening assays). Antiretroviral therapy (ART) during acute HIV infection can impact HIV-specific antibodies, antigens, and DNA/RNA detection. In this study, an HIV WP blood donor who initiated ART was monitored, evaluating the immunological and nucleic acid testing (NAT) results for early ART and discussing the potential effects on blood safety.

STUDY DESIGN AND METHODS

This was a follow-up study of a HIV WP donor detected 36 hours after high-risk sexual behavior, who was subsequently treated with ART. Immunological and NAT methods were comparatively analyzed.

RESULTS

The 4th generation HIV serologic assays were positive at Day 11, and the 3rd generation domestic anti-HIV assay was positive at Day 33. Individual donation (ID) NAT and minipool (MP) NAT of six samples were reactive, but 12-sample MP-NAT was nonreactive. ART resulted in a slow decline of HIV RNA, but HIV DNA was still detected on Day 757.

CONCLUSION

After ART, ID-NAT was more sensitive than MP-NAT or serologic detection; however, HIV DNA detection was more sensitive, with DNA but not RNA persistently detectable.

Performance of a Modified In-House HIV-1 Avidity Assay among a Cohort of Newly Diagnosed HIV-1 Infected Individuals and the Effect of ART on the Maturation of HIV-1 Specific Antibodies

BACKGROUND

Viral kinetics impact humoral immune response to HIV; antibody avidity testing helps distinguish recent (<6 months) and long-term HIV infection. This study aims to determine the frequency of recent HIV-1 infection among clients attending ICTC (Integrated Counselling and Testing Centre) using a commercial EIA, to correlate it with a modified in-house avidity assay and to study the impact of ART on anti-HIV-1 antibody maturation.

METHODS

Commercial LAg Avidity EIA was used to detect antibody avidity among 117 treatment naïve HIV-1 infected individuals. A second-generation HIV ELISA was modified for in-house antibody avidity testing and cutoff was set based on Receiver Operating Characteristic (ROC) analysis. Archived paired samples from 25 HIV-1 infected individuals before ART and after successful ART; samples from 7 individuals responding to ART and during virological failure were also tested by LAg Avidity EIA.

RESULTS

Six individuals (5.1%) were identified as recently infected by a combination of LAg avidity assay and HIV-1 viral load testing. The modified in-house avidity assay demonstrated sensitivity and specificity of 100% and 98.2%, respectively, at AI=0.69 by ROC analysis. Median ODn values of individuals when responding to ART were significantly lower than pre-ART [4.136 (IQR 3.437- 4.827) vs 4.455 (IQR 3.748-5.120), p=0.006] whereas ODn values were higher during virological failure [4.260 (IQR 3.665 - 4.515) vs 2.868 (IQR 2.247 - 3.921), p=0.16].

CONCLUSION

This modified in-house antibody avidity assay is an inexpensive method to detect recent HIV-1 infection. ART demonstrated significant effect on HIV-1 antibody avidity owing to changes in viral kinetics.

Decreased Seroreactivity in Individuals Initiating Antiretroviral Therapy during Acute HIV Infection

Antiretroviral therapy (ART) during acute HIV infection (AHI) interrupts viral dynamics and may delay the emergence of serological markers targeted by current HIV screening and confirmatory assays, thus creating challenges for correctly classifying HIV infection status. The performance of three HIV antigen/antibody combination (HIV Ag/Ab Combo) assays (the Bio-Rad GS, Abbott Architect, and Bio-Rad BioPlex 2200 assays) was evaluated with samples collected from RV254/South East Asia Research Collaboration in HIV 010 (RV254/SEARCH010) study (Bangkok, Thailand) participants at weeks 12 and 24 following the initiation of ART at Fiebig stage I (FI) (n = 23), FII (n = 39), or FIII/IV (n = 22). Supplemental, confirmatory testing was performed by the Geenius HIV 1/2 and HIV-1 Western blot assays (Bio-Rad). Samples from 30 untreated, HIV-1-infected individuals demonstrated robust HIV Ag/Ab Combo assay reactivity with well-developed HIV-1 Western blotting profiles by 24 weeks after infection. In contrast, 52.2% of samples from individuals initiating ART at FI, 7.7% of samples from individuals initiating ART at FII, and 4.5% of samples from individuals initiating ART at FIII/IV were nonreactive by the HIV Ag/Ab Combo assays, with 36.4 to 39.1% of samples having low signal-to-cutoff (S/CO) results by the Architect and BioPlex assays (S/CO < 10). Seroreversion from a reactive to a nonreactive status was observed in 10 individuals initiating ART at FII and 3 individuals initiating ART at FIII/IV. The Geenius and HIV-1 Western blot assay results were negative or indeterminate for 73.9% and 69.6% of individuals, respectively, treated at FI; 50.0% and 26.3% of individuals, respectively, treated at FII; and 54.5% and 40.9% of individuals, respectively, treated at FIII/IV. Virologic suppression of HIV-1 by ART during AHI impedes seroconversion to biomarkers of infection, limiting the utility of HIV Ag/Ab Combo and supplemental, confirmatory assays for infection status determination.

Anti-Human Immunodeficiency Virus Antibodies in the Cerebrospinal Fluid: Evidence of Early Treatment Impact on Central Nervous System Reservoir?

Background

Despite effective antiretroviral therapy (ART), human immunodeficiency virus (HIV) likely persists in the central nervous system (CNS) in treated individuals. We examined anti-HIV antibodies in cerebrospinal fluid (CSF) and blood as markers of persistence.

Methods

Human immunodeficiency virus antibodies were measured in paired CSF and serum before and after long-term treatment of chronic (n = 10) and early infection (n = 12), along with untreated early infection (n = 10).

Results

Treatment of chronic infection resulted in small reductions of anti-HIV antibodies in CSF and serum despite >10 years of suppressive ART. In untreated early infection, anti-HIV antibodies emerged in blood by day 30, whereas CSF antibodies reached similar levels 2 weeks later. Compared with long-term treatment of chronic infection, early ART initiation reduced CSF antibodies by 43-fold (P > .0001) and blood antibodies by 7-fold (P = .0003). Two individuals receiving pre-exposure prophylaxis and then ART early after infection failed to develop antibodies in CSF or blood, whereas CSF antibodies were markedly reduced in the Berlin patient.

Conclusions

To the extent that differential CSF and blood antibodies indicate HIV persistence, these data suggest a relative delay in establishment of the CNS compared with the systemic HIV reservoir that provides an opportunity for early treatment to have a greater impact on the magnitude of long-term CNS infection.

Misdiagnosis of HIV infection during a South African community-based survey: implications for rapid HIV testing

Introduction: We describe the overall accuracy and performance of a serial rapid HIV testing algorithm used in community-based HIV testing in the context of a population-based household survey conducted in two sub-districts of uMgungundlovu district, KwaZulu-Natal, South Africa, against reference fourth-generation HIV-1/2 antibody and p24 antigen combination immunoassays. We discuss implications of the findings on rapid HIV testing programmes.

Methods: Cross-sectional design: Following enrolment into the survey, questionnaires were administered to eligible and consenting participants in order to obtain demographic and HIV-related data. Peripheral blood samples were collected for HIV-related testing. Participants were offered community-based HIV testing in the home by trained field workers using a serial algorithm with two rapid diagnostic tests (RDTs) in series. In the laboratory, reference HIV testing was conducted using two fourth-generation immunoassays with all positives in the confirmatory test considered true positives. Accuracy, sensitivity, specificity, positive predictive value, negative predictive value and false-positive and false-negative rates were determined.

Results: Of 10,236 individuals enrolled in the survey, 3740 were tested in the home (median age 24 years (interquartile range 19–31 years), 42.1% males and HIV positivity on RDT algorithm 8.0%). From those tested, 3729 (99.7%) had a definitive RDT result as well as a laboratory immunoassay result. The overall accuracy of the RDT when compared to the fourth-generation immunoassays was 98.8% (95% confidence interval (CI) 98.5–99.2). The sensitivity, specificity, positive predictive value and negative predictive value were 91.1% (95% CI 87.5–93.7), 99.9% (95% CI 99.8–100), 99.3% (95% CI 97.4–99.8) and 99.1% (95% CI 98.8–99.4) respectively. The false-positive and false-negative rates were 0.06% (95% CI 0.01–0.24) and 8.9% (95% CI 6.3–12.53). Compared to true positives, false negatives were more likely to be recently infected on limited antigen avidity assay and to report antiretroviral therapy (ART) use.

Conclusions: The overall accuracy of the RDT algorithm was high. However, there were few false positives, and the sensitivity was lower than expected with high false negatives, despite implementation of quality assurance measures. False negatives were associated with recent (early) infection and ART exposure. The RDT algorithm was able to correctly identify the majority of HIV infections in community-based HIV testing. Messaging on the potential for false positives and false negatives should be included in these programmes.

The accuracy of HIV rapid testing in integrated bio-behavioral surveys of men who have sex with men across 5 Provinces in South Africa

We describe the accuracy of serial rapid HIV testing among men who have sex with men (MSM) in South Africa and discuss the implications for HIV testing and prevention.This was a cross-sectional survey conducted at five stand-alone facilities from five provinces.Demographic, behavioral, and clinical data were collected. Dried blood spots were obtained for HIV-related testing. Participants were offered rapid HIV testing using 2 rapid diagnostic tests (RDTs) in series. In the laboratory, reference HIV testing was conducted using a third-generation enzyme immunoassay (EIA) and a fourth-generation EIA as confirmatory. Accuracy, sensitivity, specificity, positive predictive value, negative predictive value, false-positive, and false-negative rates were determined.Between August 2015 and July 2016, 2503 participants were enrolled. Of these, 2343 were tested by RDT on site with a further 2137 (91.2%) having definitive results on both RDT and EIA. Sensitivity, specificity, positive predictive value, negative predictive value, false-positive rates, and false-negative rates were 92.6% [95% confidence interval (95% CI) 89.6-94.8], 99.4% (95% CI 98.9-99.7), 97.4% (95% CI 95.2-98.6), 98.3% (95% CI 97.6-98.8), 0.6% (95% CI 0.3-1.1), and 7.4% (95% CI 5.2-10.4), respectively. False negatives were similar to true positives with respect to virological profiles.Overall accuracy of the RDT algorithm was high, but sensitivity was lower than expected. Post-HIV test counseling should include discussions of possible false-negative results and the need for retesting among HIV negatives.

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.

Young age at start of antiretroviral therapy and negative HIV antibody results in HIV-infected children when suppressed

BACKGROUND

Negative results on standard HIV antibody tests have been described among HIV-infected children suppressed on antiretroviral therapy (ART) started early in life. Here, we describe the frequency and predictors of this phenomenon in a well characterized cohort of treated children.

METHODS

We selected samples from 103 HIV-infected children who started ART 14 months of age or less and from 122 children who started 6 months of age or less followed as part of two sequential clinical trials in Johannesburg, South Africa. Children had attained viral suppression on ART and had received ART for between 3 and 6.4 years (mean 4.3 years) when tested for HIV antibody using a standard ELISA (Genescreen HIV1/2 version 2; Bio-rad).

RESULTS

Only children 6 months of age or less when ART was started had negative antibody results when tested after suppression on ART several years later. Negative or low-positive antibody results were observed in 40.0, 37.0 and 27.8% of children starting ART less than 2 months of age, or starting during month 2 or 3, respectively. This dropped to 5.9, 3.5 and 5.3% if ART was started during month 4, 5 and 6, respectively. Higher CD4 percentage prior to ART initiation and no recorded intermittent viremia also predicted negative antibody results.

CONCLUSION

Testing negative on standard HIV antibody tests occurs fairly commonly among HIV-infected children who started ART 3 months of age or less and are virally suppressed. It would be prudent in clinical practice to avoid HIV antibody tests among virally suppressed, early-treated children to prevent unnecessary confusion.

Antibody Maturation in Women Who Acquire HIV Infection While Using Antiretroviral Preexposure Prophylaxis

The CAPRISA 004 preexposure prophylaxis (PrEP) randomized trial demonstrated that women who used a vaginal gel containing the antiretroviral drug tenofovir (TFV) had a 39% lower risk of acquiring human immunodeficiency virus (HIV). It is not known whether topical TFV alters the antibody response to breakthrough HIV infection. In this study, antibody maturation was evaluated using 3 serologic assays: the BED capture enzyme immunoassay (CEIA), the Bio-Plex (Luminex) assay, and the Bio-Rad avidity assay. Tests were performed using serum samples collected 3, 6, 9, 12, 24, 36, 48, and >48 months after seroconversion from 95 women in the CAPRISA 004 trial (35 in the TFV gel arm and 60 in the placebo arm). For the BED CEIA and Luminex assay, linear mixed effects models were used to examine test results by study arm. Cox proportional hazard analysis was used to examine time to avidity cutoff. Anti-HIV antibody titers did not differ between study arms. Women assigned to TFV gel demonstrated slower antibody avidity maturation, as determined by the Bio-Rad (P = .04) and gp120 Bio-Plex (P = .028) assays. Women who were assigned to receive topical TFV but became infected had slower antibody avidity maturation, with potential implications for diagnosis and antibody-based incidence assays as access to antiretroviral therapy-based PrEP is increased.

Long-term antiretroviral treatment initiated at primary HIV-1 infection affects the size, composition, and decay kinetics of the reservoir of HIV-1-infected CD4 T cells

Initiation of antiretroviral therapy during the earliest stages of HIV-1 infection may limit the seeding of a long-lasting viral reservoir, but long-term effects of early antiretroviral treatment initiation remain unknown. Here, we analyzed immunological and virological characteristics of nine patients who started antiretroviral therapy at primary HIV-1 infection and remained on suppressive treatment for >10 years; patients with similar treatment duration but initiation of suppressive therapy during chronic HIV-1 infection served as controls. We observed that independently of the timing of treatment initiation, HIV-1 DNA in CD4 T cells decayed primarily during the initial 3 to 4 years of treatment. However, in patients who started antiretroviral therapy in early infection, this decay occurred faster and was more pronounced, leading to substantially lower levels of cell-associated HIV-1 DNA after long-term treatment. Despite this smaller size, the viral CD4 T cell reservoir in persons with early treatment initiation consisted more dominantly of the long-lasting central-memory and T memory stem cells. HIV-1-specific T cell responses remained continuously detectable during antiretroviral therapy, independently of the timing of treatment initiation. Together, these data suggest that early HIV-1 treatment initiation, even when continued for >10 years, is unlikely to lead to viral eradication, but the presence of low viral reservoirs and durable HIV-1 T cell responses may make such patients good candidates for future interventional studies aiming at HIV-1 eradication and cure.

IMPORTANCE

Antiretroviral therapy can effectively suppress HIV-1 replication to undetectable levels; however, HIV-1 can persist despite treatment, and viral replication rapidly rebounds when treatment is discontinued. This is mainly due to the presence of latently infected CD4 T cells, which are not susceptible to antiretroviral drugs. Starting treatment in the earliest stages of HIV-1 infection can limit the number of these latently infected cells, raising the possibility that these viral reservoirs are naturally eliminated if suppressive antiretroviral treatment is continued for extremely long periods of time. Here, we analyzed nine patients who started on antiretroviral therapy within the earliest weeks of the disease and continued treatment for more than 10 years. Our data show that early treatment accelerated the decay of infected CD4 T cells and led to very low residual levels of detectable HIV-1 after long-term therapy, levels that were otherwise detectable in patients who are able to maintain a spontaneous, drug-free control of HIV-1 replication. Thus, long-term antiretroviral treatment started during early infection cannot eliminate HIV-1, but the reduced reservoirs of HIV-1 infected cells in such patients may increase their chances to respond to clinical interventions aiming at inducing a drug-free remission of HIV-1 infection.

HIV antibody characterization as a method to quantify reservoir size during curative interventions

Quantitative humoral profiling of recent samples from a human immunodeficiency virus (HIV)-infected adult who was cured following a delta32/delta32 CCR5 stem cell transplant in 2007 revealed no antibodies against p24, matrix, nucleocapsid, integrase, protease, and gp120, but low levels of antibodies against reverse transcriptase, tat, and gp41. Antibody levels to these HIV proteins persisted at high and stable levels in most noncontrollers, elite controllers, and antiretroviral-treated subjects, but a rare subset of controllers had low levels of antibodies against matrix, reverse transcriptase, integrase, and/or protease. Comprehensive HIV antibody profiles may prove useful for monitoring curative interventions.

Translational HIV-1 research: from routine diagnostics to new virology insights in Amsterdam, the Netherlands during 1983-2013

An HIV-1 diagnostic laboratory was established in the Academic Medical Center (AMC) of the University of Amsterdam after the discovery of human immunodeficiency virus (HIV) as the cause of the acquired immunodeficiency syndrome (AIDS). The first AIDS patients were diagnosed here in 1981 and since 1983 we have tested the samples of 50992 patients using a variety of assays that greatly improved over the years. We will describe some of the basic results from this diagnostic laboratory and then focus on the spin-off in terms of the development of novel virus assays to detect super-infections and ultra-sensitive assays to measure the intracellular HIV-1 RNA load. We also review several original research findings in the field of HIV-1 virology that stem from initial observations made in the diagnostic unit. This includes the study of genetic defects in the HIV-1 genome and time trends of the replication fitness over 30 years of viral evolution, but also the description of novel HIV-1 variants in difficult-to-diagnose clinical specimen.

Acute human immunodeficiency virus (HIV) infection presenting with fever, elevated amylase/lipase, and hematologic abnormalities

BACKGROUND

Many cases of acute human immunodeficiency virus (HIV) infection (AHI) present to the Emergency Department (ED). Early diagnosis allows a patient to modify their behavior and seek early treatment. The Emergency Physician should know that the antibody response may be absent.

OBJECTIVE

We report a case of AHI and review its presentation to increase the awareness of this important diagnosis.

CASE REPORT

A 20-year-old black man who had a history of sex with men initially presented to the ED with a chief complaint of blood per rectum when he passed stool, and chills for the prior few days. His work-up was normal, including a rapid HIV screen, and he was discharged. He returned 2 weeks later with constipation, fatigue, myalgias, decreased urination, chills, and a productive cough. His physical examination was unremarkable, HIV antibody test was negative, but his laboratory tests showed an elevation of creatine phosphokinase, amylase, and lipase. His blood count showed a normal hematocrit and white blood cell count, but there were juvenile and vacuolated white cells and giant platelets reported. HIV viral load was reported as > 1,000,000 copies/mL.

CONCLUSIONS/SUMMARY

This case illustrates that AHI can present as a non-specific illness. Patients at risk should be screened for HIV. However, AHI can occur before there is a significant antibody response. In such cases, a viral load test may help make the diagnosis, allowing for early treatment and patient counseling.

Effect of natural and ARV-induced viral suppression and viral breakthrough on anti-HIV antibody proportion and avidity in patients with HIV-1 subtype B infection

BACKGROUND

Viral suppression and viral breakthrough impact the humoral immune response to HIV infection. We evaluated the impact of viral suppression and viral breakthrough on results obtained with two cross-sectional HIV incidence assays.

METHODS

All samples were collected from adults in the US who were HIV infected for >2 years. Samples were tested with the BED capture enzyme immunoassay (BED-CEIA) which measures the proportion of IgG that is HIV-specific, and with an antibody avidity assay based on the Genetic Systems 1/2+ O ELISA. We tested 281 samples: (1) 30 samples from 18 patients with natural control of HIV-1 infection known as elite controllers or suppressors (2) 72 samples from 18 adults on antiretroviral therapy (ART), with 1 sample before and 2-6 samples after ART initiation, and (3) 179 samples from 20 virally-suppressed adults who had evidence of viral breakthrough receiving ART (>400 copies/ml HIV RNA) and with subsequent viral suppression.

RESULTS

For elite suppressors, 10/18 had BED-CEIA values <0.8 normalized optical density units (OD-n) and these values did not change significantly over time. For patients receiving ART, 14/18 had BED-CEIA values that decreased over time, with a median decrease of 0.42 OD-n (range 0.10 to 0.63)/time point receiving ART. Three patterns of BED-CEIA values were observed during viral breakthrough: (1) values that increased then returned to pre-breakthrough values when viral suppression was re-established, (2) values that increased after viral breakthrough, and (3) values that did not change with viral breakthrough.

CONCLUSIONS

Viral suppression and viral breakthrough were associated with changes in BED-CEIA values, reflecting changes in the proportion of HIV-specific IgG. These changes can result in misclassification of patients with long-term HIV infection as recently infected using the BED-CEIA, thereby influencing a falsely high value for cross-sectional incidence estimates.

False-negative post-18-month confirmatory HIV tests in HIV DNA PCR-positive children: a retrospective analysis

OBJECTIVE

The WHO guidelines for children less than 18 months old diagnosed with HIV based on presumptive clinical diagnosis or one virologic test recommend confirmatory HIV antibody testing after 18 months of age. This study describes post-18-month HIV test results following this WHO-recommended confirmatory testing strategy.

DESIGN

Case series and retrospective review of routine program data.

METHODS

Children enrolled at the Baylor Children's Clinical Center of Excellence, a pediatric and family HIV clinic in Maseru, Lesotho from December 2005 through January 2009 with a positive HIV DNA PCR at less than 18 months of age and HIV rapid test results after 18 months of age were included. Post-18-month confirmatory HIV test results are described. Factors associated with non-positive confirmatory rapid tests were determined using binary logistic regression.

RESULTS

Of the 109 children meeting inclusion criteria, 22 (20.2%) had negative and 27 (24.8%) discordant confirmatory rapid tests. Forty-six of these 49 were on antiretroviral therapy (ART). Among these 49, 11 of 24 post-18-month HIV DNA PCRs were negative, whereas nine of 10 post-18-month HIV ELISAs were positive; 29 were definitively and 17 probably HIV-infected, two were uninfected, and one had undetermined status. Only age less than 9 months at ART initiation (odds ratio 4.25, P = 0.002) was associated with non-positive rapid tests.

CONCLUSION

False-negative post-18-month confirmatory rapid tests and HIV DNA PCRs in children on ART are common, associated with early ART initiation, and may lead to inappropriate ART discontinuation and discharge from care of truly HIV-infected children.

Decreased specificity of an assay for recent infection in HIV-1-infected patients on highly active antiretroviral treatment: implications for incidence estimates

The aim of this study was to estimate the rate of misclassification in treated HIV patients who initiated treatment at the chronic stage of HIV infection using an enzyme immunoassay (EIA) that discriminates between recent infection (RI; within 6 months) and established infection. The performance of EIA-RI was evaluated in 96 HIV-1 chronically infected patients on highly active antiretroviral therapy (HAART) with an undetectable viral load (VL) for at least 3 years. Demographic data, HIV-1 viral load, CD4(+) T-cell count, viral subtype, and treatment duration were collected. The subset of misclassified patients was further analyzed using samples collected annually. The impact on incidence estimates was evaluated by simulation. The specificity in treated patients was significantly lower (70.8 to 77.1%) than that observed in untreated patients (93.3 to 99.3%, P < 0.001). Patients falsely classified as recently infected had been treated for a longer period and had longer-term viral suppression than those correctly classified. The loss of specificity of the test due to treatment may have a dramatic impact on the accuracy of the incidence estimates, with a major impact when HIV prevalence is high. The cross-sectional studies intended to derive HIV incidence must collect information on treatment or, alternatively, should include detection of antiretroviral drugs in blood specimens to rule out treated patients from the calculations.

Suboptimal immune reconstitution in vertically HIV infected children: a view on how HIV replication and timing of HAART initiation can impact on T and B-cell compartment

Today, HIV-infected children who have access to treatment face a chronic rather than a progressive and fatal disease. As a result, new challenges are emerging in the field. Recent lines of evidence outline several factors that can differently affect the ability of the immune system to fully reconstitute and to mount specific immune responses in children receiving HAART. In this paper, we review the underlying mechanisms of immune reconstitution after HAART initiation among vertically HIV-infected children analyzing the possible causes of suboptimal responses.

High specificity of line-immunoassay based algorithms for recent HIV-1 infection independent of viral subtype and stage of disease

Background

Serologic testing algorithms for recent HIV seroconversion (STARHS) provide important information for HIV surveillance. We have shown that a patient's antibody reaction in a confirmatory line immunoassay (INNO-LIA^TM HIV I/II Score, Innogenetics) provides information on the duration of infection. Here, we sought to further investigate the diagnostic specificity of various Inno-Lia algorithms and to identify factors affecting it.

Methods

Plasma samples of 714 selected patients of the Swiss HIV Cohort Study infected for longer than 12 months and representing all viral clades and stages of chronic HIV-1 infection were tested blindly by Inno-Lia and classified as either incident (up to 12 m) or older infection by 24 different algorithms. Of the total, 524 patients received HAART, 308 had HIV-1 RNA below 50 copies/mL, and 620 were infected by a HIV-1 non-B clade. Using logistic regression analysis we evaluated factors that might affect the specificity of these algorithms.

Results

HIV-1 RNA <50 copies/mL was associated with significantly lower reactivity to all five HIV-1 antigens of the Inno-Lia and impaired specificity of most algorithms. Among 412 patients either untreated or with HIV-1 RNA ≥50 copies/mL despite HAART, the median specificity of the algorithms was 96.5% (range 92.0-100%). The only factor that significantly promoted false-incident results in this group was age, with false-incident results increasing by a few percent per additional year. HIV-1 clade, HIV-1 RNA, CD4 percentage, sex, disease stage, and testing modalities exhibited no significance. Results were similar among 190 untreated patients.

Conclusions

The specificity of most Inno-Lia algorithms was high and not affected by HIV-1 variability, advanced disease and other factors promoting false-recent results in other STARHS. Specificity should be good in any group of untreated HIV-1 patients.

Prevalence and characteristics of patients with undiagnosed HIV infection in an urban emergency department

The Centers for Disease Control and Prevention (CDC) recommends offering HIV testing to persons admitted to emergency departments (EDs). Whether by opt-in or opt-out, many EDs (including our own) have found a seroprevalence of 0.8-1.5% when rapid testing is offered. The true seropositivity rate is unknown. We performed a retrospective chart analysis upon all patients presenting to our ED over a 2-week period in the fall of 2007 who had serum drawn as a part of their emergency care. Demographics and clinical characteristics were linked via de-identified serum, which was sent for HIV testing. Nine hundred fifty nine patients had sera available for rapid HIV testing. One hundred twenty one (13%) samples were reactive via the OraQuick(®) test (OraSure Technologies, Bethlehem, PA), a point of care rapid antibody test. Due to concerns about the appropriateness of sera as substrate for the OraQuick(®) technology, reactive samples were retested via standard enzyme immunoassay (EIA)/Western blot. One hundred twelve analyzable samples were retested-38 were positive and 27 of these were from patients who reported a history of HIV infection. The rate of undiagnosed HIV infection was 1.2% (11/914 potentially analyzable samples). Of all patients with HIV in our ED, 29% of them were presumably unaware of their diagnosis. In conclusion, HIV seroprevalence in our urban ED is high, and a large fraction of the patients appears to be unaware of the infection.

Seronegative HIV-1 infection: a review of the literature

HIV-1-specific antibodies can be detected in HIV-1-positive patients within weeks of primary infection. Rare cases have been reported of patients who are persistently seronegative despite evidence of HIV-1 infection. We present a retrospective review of the clinical, virologic and immunologic characteristics of 25 persistently seronegative patients whose cases have been published to date and postulate a biologic mechanism for this phenomenon.

Immune activation and antibody responses in non-progressing elite controller individuals infected with HIV-1

An extremely rare subset of patients infected with HIV-1 designated as "non-progressing elite controllers" appears to be able to maintain stable CD4(+) T-cell counts and a median plasma viremia below the detection limit of current ultrasensitive assays (<50-80 copies/ml of plasma) for >10 years in the absence of antiretroviral therapy. Lymphocyte subsets (CD4(+), CD8(+)), immune activation markers (HLA-DR(+), CD38(+), Beta-2-microglobulin), and HIV-specific antibody responses were longitudinally examined in four non-progressing elite controllers over more than 5 years. Two control groups of seronegative healthy individuals and untreated patients infected with HIV-1 presenting detectable viremia were also included. None of the non-progressing elite controllers displayed the high T-cell activation levels generally seen in the seropositive individuals, keeping them within the normal range. Three non-progressing elite controllers showed no significant immune system abnormalities when compared to seronegative individuals, displaying a low proportion of HIV-1-specific binding antibodies and low avidity index, similar to those observed for individuals infected recently with HIV-1. One non-progressing elite controller exhibited CD8(+) T-cell counts and beta2-M levels above normal ranges and developed a low but "mature" (high-avidity) HIV-1-specific antibody response. Thus, the non-progressing elite controllers are able to maintain normal T-cell activation levels, which may contribute to prevent, or greatly reduce, the damage of the immune system typically induced by the HIV-1 over time. They are, however, immunologically heterogeneous and very low levels of antigen exposure seem to occur in these patients, sufficient for sustaining a low, but detectable, HIV-1-specific immunity.