Cardiometabolic health in people with HIV: expert consensus review

OBJECTIVES

To develop consensus data statements and clinical recommendations to provide guidance for improving cardiometabolic health outcomes in people with HIV based on the knowledge and experience of an international panel of experts.

METHODS

A targeted literature review including 281 conference presentations, peer-reviewed articles, and background references on cardiometabolic health in adults with HIV published between January 2016 and April 2022 was conducted and used to develop draft consensus data statements. Using a modified Delphi method, an international panel of 16 experts convened in workshops and completed surveys to refine consensus data statements and generate clinical recommendations.

RESULTS

Overall, 10 data statements, five data gaps and 14 clinical recommendations achieved consensus. In the data statements, the panel describes increased risk of cardiometabolic health concerns in people with HIV compared with the general population, known risk factors, and the potential impact of antiretroviral therapy. The panel also identified data gaps to inform future research in people with HIV. Finally, in the clinical recommendations, the panel emphasizes the need for a holistic approach to comprehensive care that includes regular assessment of cardiometabolic health, access to cardiometabolic health services, counselling on potential changes in weight after initiating or switching antiretroviral therapy and encouraging a healthy lifestyle to lower cardiometabolic health risk.

CONCLUSIONS

On the basis of available data and expert consensus, an international panel developed clinical recommendations to address the increased risk of cardiometabolic disorders in people with HIV to ensure appropriate cardiometabolic health management for this population.

3D Bioprinted Neural-Like Tissue as a Platform to Study Neurotropism of Mouse-Adapted SARS-CoV-2

The effects of neuroinvasion by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) become clinically relevant due to the numerous neurological symptoms observed in Corona Virus Disease 2019 (COVID-19) patients during infection and post-COVID syndrome or long COVID. This study reports the biofabrication of a 3D bioprinted neural-like tissue as a proof-of-concept platform for a more representative study of SARS-CoV-2 brain infection. Bioink is optimized regarding its biophysical properties and is mixed with murine neural cells to construct a 3D model of COVID-19 infection. Aiming to increase the specificity to murine cells, SARS-CoV-2 is mouse-adapted (MA-SARS-CoV-2) in vitro, in a protocol first reported here. MA-SARS-CoV-2 reveals mutations located at the Orf1a and Orf3a domains and is evolutionarily closer to the original Wuhan SARS-CoV-2 strain than SARS-CoV-2 used for adaptation. Remarkably, MA-SARS-CoV-2 shows high specificity to murine cells, which present distinct responses when cultured in 2D and 3D systems, regarding cell morphology, neuroinflammation, and virus titration. MA-SARS-CoV-2 represents a valuable tool in studies using animal models, and the 3D neural-like tissue serves as a powerful in vitro platform for modeling brain infection, contributing to the development of antivirals and new treatments for COVID-19.

Efficacy and Safety of a Recombinant Plant-Based Adjuvanted Covid-19 Vaccine

BACKGROUND

Coronavirus-like particles (CoVLP) that are produced in plants and display the prefusion spike glycoprotein of the original strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are combined with an adjuvant (Adjuvant System 03 [AS03]) to form the candidate vaccine.

METHODS

In this phase 3, multinational, randomized, placebo-controlled trial conducted at 85 centers, we assigned adults (≥18 years of age) in a 1:1 ratio to receive two intramuscular injections of the CoVLP+AS03 vaccine or placebo 21 days apart. The primary objective of the trial was to determine the efficacy of the CoVLP+AS03 vaccine in preventing symptomatic coronavirus disease 2019 (Covid-19) beginning at least 7 days after the second injection, with the analysis performed after the detection of at least 160 cases.

RESULTS

A total of 24,141 volunteers participated in the trial; the median age of the participants was 29 years. Covid-19 was confirmed by polymerase-chain-reaction assay in 165 participants in the intention-to-treat population; all viral samples that could be sequenced contained variants of the original strain. Vaccine efficacy was 69.5% (95% confidence interval [CI], 56.7 to 78.8) against any symptomatic Covid-19 caused by five variants that were identified by sequencing. In a post hoc analysis, vaccine efficacy was 78.8% (95% CI, 55.8 to 90.8) against moderate-to-severe disease and 74.0% (95% CI, 62.1 to 82.5) among the participants who were seronegative at baseline. No severe cases of Covid-19 occurred in the vaccine group, in which the median viral load for breakthrough cases was lower than that in the placebo group by a factor of more than 100. Solicited adverse events were mostly mild or moderate and transient and were more frequent in the vaccine group than in the placebo group; local adverse events occurred in 92.3% and 45.5% of participants, respectively, and systemic adverse events in 87.3% and 65.0%. The incidence of unsolicited adverse events was similar in the two groups up to 21 days after each dose (22.7% and 20.4%) and from day 43 through day 201 (4.2% and 4.0%).

CONCLUSIONS

The CoVLP+AS03 vaccine was effective in preventing Covid-19 caused by a spectrum of variants, with efficacy ranging from 69.5% against symptomatic infection to 78.8% against moderate-to-severe disease. (Funded by Medicago; ClinicalTrials.gov number, NCT04636697.).

Detection of coinfection with Chikungunya virus and Dengue virus serotype 2 in serum samples of patients in State of Tocantins, Brazil

BACKGROUND

The co-circulation of Chikungunya (CHIKV), Dengue (DENV) and Zika (ZIKV) viruses increased the risk of outbreaks and coinfections among them. Here, we report cases of coinfection in clinical samples from state of Tocantins, Brazil.

METHODS

In 2017, the Central Public Health Laboratory (LACEN) received samples of patients who consulted health units with symptoms compatible with arboviral infections. A total of 102 samples were sent to the Retrovirology Laboratory at the Federal University of São Paulo, where they were tested by RT-qPCR to confirm DENV, ZIKV and CHIKV infections and to detect coinfected patients.

RESULTS

We identified with CHIKV monoinfection (52), DENV serotypes 1 (28) and serotypes 2 (22). We did not detect ZIKV. Five patients were characterized with coinfection involving CHIKV and DENV serotype 2.

CONCLUSIONS

The presence of co-circulating arboviruses increases the chance of coinfection and demonstrates the importance of differential diagnosis and vector control.

Nitric oxide stimulates a PKC-Src-Akt signaling axis which increases human immunodeficiency virus type 1 replication in human T lymphocytes

Human immunodeficiency virus (HIV) infections are typically accompanied by high levels of secreted inflammatory cytokines and generation of high levels of reactive oxygen species (ROS). To elucidate how HIV-1 alters the cellular redox environment during viral replication, we used human HIV-1 infected CD4⁺T lymphocytes and uninfected cells as controls. ROS and nitric oxide (NO) generation, antioxidant enzyme activity, protein phosphorylation, and viral and proviral loads were measured at different times (2-36 h post-infection) in the presence and absence of the NO donor S-nitroso-N-acetylpenicillamine (SNAP). HIV-1 infection increased ROS generation and decreased intracellular NO content. Upon infection, we observed increases in copper/zinc superoxide dismutase (SOD1) and glutathione peroxidase (GPx) activities, and a marked decrease in glutathione (GSH) concentration. Exposure of HIV-1 infected CD4⁺T lymphocytes to SNAP resulted in an increasingly oxidizing intracellular environment, associated with tyrosine nitration and SOD1 inhibition. In addition, SNAP treatment promoted phosphorylation and activation of the host's signaling proteins, PKC, Src kinase and Akt. Inhibition of PKC leads to inhibition of Src kinase strongly suggesting that PKC is the upstream element in this signaling cascade. Changes in the intracellular redox environment after SNAP treatment had an effect on HIV-1 replication as reflected by increases in proviral and viral loads. In the absence or presence of SNAP, we observed a decrease in viral load in infected CD4⁺T lymphocytes pre-incubated with the PKC inhibitor GF109203X. In conclusion, oxidative/nitrosative stress conditions derived from exposure of HIV-1-infected CD4⁺T lymphocytes to an exogenous NO source trigger a signaling cascade involving PKC, Src kinase and Akt. Activation of this signaling cascade appears to be critical to the establishment of HIV-1 infection.

Individual factors associated with time to non-adherence to ART pick-up within HIV care and treatment services in three health facilities of Zambézia Province, Mozambique

Introduction

Mozambique has made significant gains in addressing its HIV epidemic, yet adherence to visit schedules remains a challenge. HIV programmatic gains to date could be impaired if adherence and retention to ART remains low. We investigate individual factors associated with non-adherence to ART pick-up in Mozambique.

Methods

This was a retrospective cohort of patients initiating ART between January 2013 and June 2014. Non-adherence to ART pick-up was defined as a delay in pick-up ≥ 15 days. Descriptive statistics were used to calculate socio-demographic and clinical characteristics. Adherence to ART pick-up was assessed using Kaplan Meier estimates. Cox proportional hazards model was used to determine factors associated with non-adherence.

Results

1,413 participants were included (77% female). Median age was 30.4 years. 19% of patients remained adherent to ART pick-up during the evaluation period, while 81% of patients were non-adherent to ART pick-up. Probability of being non-adherent to ART pick-up by 166 days following initiation was 50%. In univariate analysis, being widowed was associated with higher adherence to ART pick-up than other marital status groups (p = 0.01). After adjusting, being ≥35 years (aHR: 0.843, 95% CI: 0.738–0.964, p = 0.012); receiving efavirenz (aHR: 0.932, 95% CI: 0.875–0.992, p = 0.026); and being urban (aHR: 0.754, 95% CI: 0.661–0.861, p<0.0001) were associated with improved adherence. Non-participation in a Community ART Support Group (CASG) was associated with a 43% increased hazard of non-adherence to ART pick-up (aHR 1.431, 1.192–1.717, p<0.0001)

Conclusions

Interventions should focus on the first 6 months following ARV initiation for improvements. Younger persons and widows are two target groups for better understanding facilitators and barriers to visit schedule adherence. Future strategies should explore the benefits of joining CASGs earlier in one´s treatment course. Finally, greater efforts should be made to accelerate the scale-up of viral load capacity and HIV resistance monitoring.

Brazilian network for HIV Drug Resistance Surveillance (HIV-BresNet): a survey of treatment-naive individuals

INTRODUCTION

In Brazil, more than 487,450 individuals are currently undergoing antiretroviral treatment. In order to monitor the transmission of drug-resistant strains and HIV subtype distribution in the country, this work aimed to estimate its prevalence and to characterize the nationwide pretreatment drug resistance in individuals recently diagnosed with HIV between 2013 and 2015.

METHODS

The HIV threshold survey methodology (HIV-THS, WHO) targeting antiretroviral-naive individuals with recent HIV diagnosis was utilized, and subjects were selected from 51 highly populated cities in all five Brazilian macroregions. The HIV pol genotypic test was performed by genomic sequencing.

RESULTS

We analysed samples from 1568 antiretroviral-naive individuals recently diagnosed with HIV, and the overall transmitted drug resistance (TDR) prevalence was 9.5% (150 sequences). The regional prevalence of resistance according to Brazilian geographical regions was 9.4% in the northeast, 11.2% in the southeast, 6.8% in the central region, 10.2% in the north and 8.8% in the south. The inhibitor-specific TDR prevalence was 3.6% for nucleoside reverse transcriptase inhibitors (NRTIs), 5.8% for non-nucleoside reverse transcriptase inhibitors (NNRTIs) and 1.6% for protease inhibitors (PIs); 1.0% of individuals presented resistance to more than one class of inhibitors. Overall, subtype B was more prevalent in every region except for the southern, where subtype C prevails.

CONCLUSIONS

To the best of our knowledge, this is the first TDR study conducted in Brazil with nationwide representative sampling. The TDR prevalence revealed a moderate rate in the five Brazilian geographical regions, although some cities presented higher TDR prevalence rates, reaching 14% in São Paulo, for example. These results further illustrate the importance of surveillance studies for designing future strategies in primary antiretroviral therapy, aiming to mitigate TDR, as well as for predicting future trends in other regions of the globe where mass antiretroviral (ARV) treatment was implemented.

High rates of human immunodeficiency virus type 1 mutational profiles by single-genome amplification after 48-hour propagation in peripheral blood mononuclear cells at different levels of cell activation

Human immunodeficiency virus type 1 (HIV-1) genetic diversity is one of the most important features of HIV-1 infections and the result of error accumulation during reverse transcription and of high viral turnover. HIV-1 reverse transcription is influenced by factors such as the level of nucleotides and/or the cellular activation state. HIV-1 diversity was investigated after 48 h of viral propagation in peripheral blood mononuclear cells (PBMCs) obtained from healthy donors in three different cell culture conditions: (1) resting PBMCs, (2) simultaneous infection and PBMC activation, and (3) PBMC activation 72 h before infection. Cellular DNA was extracted and proviruses of each culture condition were amplified. Single-genome PCR clones were obtained and the protease and reverse transcriptase of the pol gene were sequenced. An elevated number of nucleotide substitutions in all three culture conditions were observed. In condition 1, the mutational rate observed ranged from 1.0 × 10(-3) to 2.1 × 10(-2), the genetic diversity was 0.6%, and hypermutation was observed in 7.1% of sequenced clones. In condition 2, the mutational rate ranged from 1.0 × 10(-3) to 1.0 × 10(-2), the genetic diversity was 0.8%, and hypermutation affected 6.7% of clones. In condition 3, the mutational rate ranged from 2.8 × 10(-3) to 1.1 × 10(-2), the genetic diversity was 1%, and 5.9% of clones were hypermutated. Substitutions occurred more frequently in some specific nucleotide stretches, and a common pattern for substitutions in all the different conditions was identified. There was a significant accumulation of mutations during the initial periods of in vitro HIV-1 propagation irrespective of culture conditions. The rapid accumulation of virus diversity might represent a viral strategy when colonizing new hosts. Complementary studies are necessary to allow for a better understanding of the initial periods of infection, which represent a crucial event related to disease progression.

Short communication: HIV type 1 subtype BF leads to faster CD4+ T cell loss compared to subtype B

Although it has been suggested that biological differences among HIV-1 subtypes exist, their possible influence on disease progression has not been fully revealed. In particular, the increasing emergence of recombinants stresses the need to characterize disease presentation in persons infected by these diverse HIV-1 forms. We explored this issue among 83 Brazilian subjects infected with either HIV-1 subtype B or recombinant subtype BF, all followed since incident infection in a cohort study. Viral subtypes were assigned by full length sequencing of HIV-1 genomes. We observed that the baseline measures for CD4(+) T cells and viral load did not differ between the groups. However, longitudinal analysis revealed that subtype BF was clearly associated with a faster CD4(+) T cell decline compared to infection with subtype B, in spite of a similar plasma HIV-1 load. While subtype B-infected subjects presented a loss of 3.6 CD4(+) T cells/μl per month, subtype BF-infected individuals showed a monthly decay of 6.3 CD4(+) T cells/μl (p<0.01). The time to reach 350 CD4(+) T cells/μl and the time to start antiretroviral treatment were also shorter in subtype BF-infected persons. The elucidation of an accelerated CD4(+) T cell loss associated with subtype BF suggests that this HIV-1 genetic form could be more pathogenic than subtype B.

Short communication: Evaluation of GB virus C/hepatitis G viral load among HIV type 1-coinfected patients in São Paulo, Brazil

Recent studies suggest that GB virus C/hepatitis G virus (GBV-C/HGV) infection in HIV-positive individuals is associated with a slower progression to AIDS, leading to a lower HIV viral load and higher counts of CD4(+) T cells, although many studies have failed to demonstrate these beneficial effects. We developed a Real-Time PCR (TaqMan RT qPCR) to quantify the viral load of GBV-C/HGV in 102 HIV-1-infected patients, who were also evaluated for the presence of anti-E2. The prevalence of GBV-C/HGV infection was 21% among infected patients and the mean plasma viral load was 3.62 ± 0.64 log(10) copies/ml. Despite the high prevalence, there was no statistical difference when we compared the mean viral load (p≤0.46) and the average count of CD4(+) (p≤0.29) and CD8(+) (p≤0.64) among patients infected by GBV-C/HGV and HIV and patients infected only by HIV. This fact can be explained by the number of patients included in the study. Nevertheless, compared to other studies, we observed a discrete number of patients with undetectable HIV load and lower median viral load in the group presenting GBV-C/HGV RNA. Our study suggests that there may be an impact on HIV viral load in GBV-C/HGV-coinfected patients. However, further studies are needed to elucidate the molecular and cellular mechanisms involved in this viral interaction, previously reported in other studies, with the aim of contributing to the development of new targets for drugs against HIV.

Vicriviroc plus optimized background therapy for treatment-experienced subjects with CCR5 HIV-1 infection: final results of two randomized phase III trials

BACKGROUND

Vicriviroc, a novel HIV CCR5 antagonist, demonstrated significant efficacy and favorable tolerability in phase II trials in treatment-experienced subjects, supporting further evaluation in phase III studies.

METHODS

Two identical double-blind, placebo (PBO)-controlled trials in CCR5-tropic HIV-infected subjects with documented resistance to two antiretroviral classes were conducted. Subjects were randomized to vicriviroc 30 mg QD (N = 571) or PBO (N = 286) with open-label optimized background therapy (OBT) containing ≥2 fully active antiretroviral drugs. The primary endpoint was percentage of subjects with <50 copies/mL HIV RNA at 48 weeks. It was analyzed in a logistic regression with treatment (vicriviroc + OBT/PBO + OBT), use of enfuvirtide in baseline OBT (yes/no), and baseline HIV RNA (≤100,000/>100,000 copies/mL) as covariates. In addition, a pre-planned analysis to examine other efficacy and safety endpoints was conducted.

RESULTS

Baseline characteristics of the pooled mITT population (vicriviroc, n = 486; PBO, n = 235) included mean HIV RNA of 4.6 log(10) copies/mL and mean CD4 count of 257 cells/μL. Approximately 60% of subjects received ≥3 active drugs in the OBT. The percentage of subjects with <50 copies/mL HIV RNA was not significantly different between vicriviroc and PBO at week 48 (64% vs 62%, p = 0.6). However, in subjects receiving ≤2 active drugs in their OBT, the proportion achieving <50 copies/mL HIV RNA was higher in those receiving vicriviroc compared with PBO (70% vs 55%, p = 0.02).

CONCLUSIONS

The studies failed to show significant efficacy gains when vicriviroc was added to OBT. However, given the efficacy results of earlier vicriviroc trials and other CCR5 antagonist, studies are needed to define the role of this class of drugs in the treatment of HIV. Clinical trial identifier: http://www.clinicaltrial.gov/: VICTOR-E3 (NCT00523211) and VICTOR-E4 (NCT00474370).

The Brazilian network for HIV-1 genotyping external quality control assurance programme

The Brazilian network for genotyping is composed of 21 laboratories that perform and analyze genotyping tests for all HIV-infected patients within the public system, performing approximately 25,000 tests per year. We assessed the interlaboratory and intralaboratory reproducibility of genotyping systems by creating and implementing a local external quality control evaluation. Plasma samples from HIV-1-infected individuals (with low and intermediate viral loads) or RNA viral constructs with specific mutations were used. This evaluation included analyses of sensitivity and specificity of the tests based on qualitative and quantitative criteria, which scored laboratory performance on a 100-point system. Five evaluations were performed from 2003 to 2008, with 64% of laboratories scoring over 80 points in 2003, 81% doing so in 2005, 56% in 2006, 91% in 2007, and 90% in 2008 (Kruskal-Wallis, p = 0.003). Increased performance was aided by retraining laboratories that had specific deficiencies. The results emphasize the importance of investing in laboratory training and interpretation of DNA sequencing results, especially in developing countries where public (or scarce) resources are used to manage the AIDS epidemic.

Differential persistence of transmitted HIV-1 drug resistance mutation classes

BACKGROUND

Transmitted human immunodeficiency virus type 1 (HIV-1) drug resistance (TDR) mutations can become replaced over time by emerging wild-type viral variants with improved fitness. The impact of class-specific mutations on this rate of mutation replacement is uncertain.

METHODS

We studied participants with acute and/or early HIV infection and TDR in 2 cohorts (San Francisco, California, and São Paulo, Brazil). We followed baseline mutations longitudinally and compared replacement rates between mutation classes with use of a parametric proportional hazards model.

RESULTS

Among 75 individuals with 195 TDR mutations, M184V/I became undetectable markedly faster than did nonnucleoside reverse-transcriptase inhibitor (NNRTI) mutations (hazard ratio, 77.5; 95% confidence interval [CI], 14.7-408.2; P<.0001), while protease inhibitor and NNRTI replacement rates were similar. Higher plasma HIV-1 RNA level predicted faster mutation replacement, but this was not statistically significant (hazard ratio, 1.71 log(10) copies/mL; 95% CI, .90-3.25 log(10) copies/mL; P=.11). We found substantial person-to-person variability in mutation replacement rates not accounted for by viral load or mutation class (P<.0001).

CONCLUSIONS

The rapid replacement of M184V/I mutations is consistent with known fitness costs. The long-term persistence of NNRTI and protease inhibitor mutations suggests a risk for person-to-person propagation. Host and/or viral factors not accounted for by viral load or mutation class are likely influencing mutation replacement and warrant further study.

Prevalence, incidence density, and genotype distribution of GB virus C infection in a cohort of recently HIV-1-infected subjects in Sao Paulo, Brazil

BACKGROUND

The results of previous studies elsewhere have indicated that GB virus C (GBV-C) infection is frequent in patients infected with the human immunodeficiency virus type 1 (HIV-1) due to similar transmission routes of both viruses. The aim of this study was to determine the prevalence, incidence density and genotypic characteristics of GBV-C in this population.

METHODOLOGY/PRINCIPAL FINDINGS

The study population included 233 patients from a cohort primarily comprised of homosexual men recently infected with HIV-1 in São Paulo, Brazil. The presence of GBV-C RNA was determined in plasma samples by reverse transcriptase-nested polymerase chain reaction and quantified by real-time PCR. GBV-C genotypes were determined by direct sequencing. HIV viral load, CD4+ T lymphocyte and CD8+ T lymphocyte count were also tested in all patients. The overall prevalence of GBV-C infection was 0.23 (95% CI: 0.18 to 0.29) in the study group. There was no significant difference between patients with and without GBV-C infection and Glycoprotein E2 antibody presence regarding age, sex, HIV-1 viral load, CD4+ and CD8+T cell counts and treatment with antiretroviral drugs. An inverse correlation was observed between GBV-C and HIV-1 loads at enrollment and after one year. Also, a positive but not significant correlation was observed between GBV-C load and CD4+ T lymphocyte. Phylogenetic analysis of the GBV-C isolates revealed the presence of genotype 1 and genotype 2, these sub classified into subtype 2a and 2b.

CONCLUSION/SIGNIFICANCE

GBV-C infection is common in recently HIV -1 infected patients in Sao Paulo, Brazil and the predominant genotype is 2b. This study provides the first report of the GBV-C prevalence at the time of diagnosis of HIV-1 and the incidence density of GBV-C infection in one year.

Short communication: intermediate prevalence of HIV type 1 primary antiretroviral resistance in Ceará State, Northeast Brazil

Brazil is a large developing country where almost all FDA-licensed antiretrovirals are made available to more than 200,000 individuals under antiretroviral treatment. General primary HIV-1 resistance in Brazil is assumed to be low, but data are scarce, especially in the Northeast region. To evaluate the prevalence of primary HIV-1 antiretroviral resistance in the state of Ceará, Brazil, a cross-sectional prospective study of antiretroviral-naive HIV-1-infected individuals was performed between May 2008 and May 2009. Genomic sequences of reverse transcriptase and protease regions of the pol gene of HIV-1 using PCR products were obtained. Mutations related to resistance to NRTI, NNRTI, and PI were evaluated according to the WHO mutation list for primary resistance surveillance, which excludes common polymorphisms. Seventy-four individuals were evaluated (50% male) with a median age 30 years; 55.4% were men who have sex with men. Median CD4(+) T lymphocyte counts were 418 and 960 cells/mm(3) and the median viral loads were 4.41 and 4.46 log(10) RNA copies/ml for individuals older and younger that 18 years, respectively. Twenty-seven percent of patients were symptomatic. Five patients (6.8%) were recently infected, as detected by the BED test. The mutations 41L, 67N, 215D, 219Q, 101E, and 103N in the RT and 32I, 46I, 54V, 82T, and 90M, in the PR were identified in 9.5% of samples, more frequently in HIV subtype B (85.1%). A significant level of primary HIV resistance was detected in urban Northeast Brazil, a region geographically distant from the more highly populated and wealthier areas of Southeast Brazil, and this emphasizes the need for monitoring resistance in the studied area.

Evaluation of primary resistance to HIV entry inhibitors among brazilian patients failing reverse transcriptase/protease inhibitors treatment reveal high prevalence of maraviroc resistance-related mutations

Entry inhibitor is a new class of drugs that target the viral envelope protein. This region is variable; hence resistance to these drugs may be present before treatment. The aim of this study was to analyze the frequency of patients failing treatment with transcriptase reverse and protease inhibitors that would respond to the entry inhibitors Enfuvirtide, Maraviroc, and BMS-806. The study included 100 HIV-1 positive patients from one outpatient clinic in the city of Sao Paulo, for whom a genotype test was requested due to treatment failure. Proviral DNA was amplified and sequenced for regions of gp120 and gp41. A total of 80 could be sequenced and from those, 73 (91.3%), 5 (6.3%) and 2 (2.5%) were classified as subtype B, F, and recombinants (B/ F and B/C), respectively. CXCR4 co-receptor use was predicted in 30% of the strains. Primary resistance to Enfuvirtide was found in 1.3%, following the AIDS Society consensus list, and 10% would be considered resistant if a broader criterion was used. Resistance to BMS-806 was higher; 6 (7.5%), and was associated to non-B strains. Strikingly, 27.5% of samples harbored one or more mutation among A316T, I323V, and S405A, which have been related to decreased susceptibility of Maraviroc; 15% of them among viruses predictive to be R5. A more common mutation was A316T, which was associated to the Brazilian B strain harboring the GWGR motif at the tip of V3 loop and their derivative sequences. These results may be impact guidelines for genotype testing and treatment in Brazil.

Prevalence, distribution and correlates of endocervical human papillomavirus types in Brazilian women

We determined the prevalence, distribution and correlates of human papillomavirus (HPV) types in 386 mixed-income, sexually active women in São Paulo, Brazil. Endocervical samples were tested for HPV DNA with L1 primers MY09 and MY11; negative and indeterminate samples were retested using GP 5+/6+ consensus primers. HPV was detected in 35% of all women; high-risk/probable high-risk types in 20%; low-risk types in 7%; and an indeterminate type in 10%. Twenty-five HPV types were found overall: 17 (probable) high-risk types and eight low-risk types. Approximately one-third (29%) of women with HPV infection were positive for type 16 or 18 and 36% were positive for types 6, 11, 16 or 18. The presence of (probable) high-risk HPV was associated with younger age, more lifetime sex partners and abnormal vaginal flora. Additional studies mapping the distribution of HPV types worldwide are necessary to prepare for vaccination programmes and direct future vaccine development.

Intrahost and interhost variability of the HIV type 1 nef gene in Brazilian children

Many aspects of HIV-1 pathogenesis are affected by Nef protein activity, and efforts have been made to study variation in the nef gene and how that variation relates to disease outcome. We studied the genetic diversity of the nef gene in distinct clones obtained from the same patient (intrahost) and in sequences obtained from different hosts (interhost). The set of sequences analyzed was obtained from HIV-1-infected Brazilian children and contained 112 clones from 25 children (intrahost samples), as well as 55 sequences from epidemiologically unlinked children (interhost samples). We found extensive site polymorphisms and amino acid length variations, mainly in the amino terminal region of the nef gene, between the myristoylation motif (MGxxxS) and the MHC-1 downregulation motif (Rxx). Analysis of the sequences deposited in the Los Alamos HIV sequences database ( www.hiv.lanl.gov ) indicated that the most frequent motif at the MHC-1 downregulation site in the subtype B strain is R(86%)A(64%)E(82%) (n = 1040) and R(78%)T(74%)E(56%) in the subtype C strain (n = 549). Conversely, the Brazilian subtype B isolates presented the motif R(81%)T(62%)E(67%) at this site (n = 64). A detailed analysis of selective pressures identified a concentration of codons under strong positive selection in the amino terminal region of the nef gene. We also determined that different sites are under positive selection in the subtype B and subtype C viruses. The amino acid composition in the MHC-1 downregulation motif of the nef gene in our sequences may indicate a distinct adaptive pattern of HIV-1 subtype B to the Brazilian host population.

Brazilian Network for HIV Drug Resistance Surveillance: a survey of individuals recently diagnosed with HIV

Use of antiretrovirals is widespread in Brazil, where more than 200,000 individuals are under treatment. Although general prevalence of primary antiretroviral resistance in Brazil is low, systematic sampling in large metropolitan areas has not being performed.The HIV Threshold Survey methodology (HIV-THS, WHO) was utilized, targeting Brazil's four major regions and selecting the six most populated state capitals: Sao Paulo, Rio de Janeiro, Salvador, Porto Alegre, Brasilia and Belem. We were able to sequence samples from 210 individuals with recent HIV diagnosis, 17 of them (8.1%) carrying HIV isolates with primary antiretroviral resistance mutations. Five, nine and four isolates showed mutations related to resistance to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs), respectively. Using HIV-THS, we could find an intermediate level of transmitted resistance (5% to 15%) in Belem/Brasilia, Sao Paulo and Rio de Janeiro. Lower level of transmitted resistance (<5%) were observed in the other areas. Despite the extensive antiretroviral exposure and high rates of virologic antiretroviral failure in Brazil, the general prevalence of primary resistance is still low. However, an intermediate level of primary resistance was found in the four major Brazilian cities, confirming the critical need to start larger sampling surveys to better define the risk factors associated with transmission of resistant HIV.

Selective pressures of human immunodeficiency virus type 1 (HIV-1) during pediatric infection

Pediatric HIV-1 infection presents remarkable features that are distinct from those observed in adult infection. In vertically HIV-1-infected children, the viral load declines more slowly, and the cytotoxic T-lymphocyte response emerges late, only after the sixth month of life. This response generally tends to be narrow and less intense than that seen in adults. While the nuances of immune response at the cellular level during pediatric HIV-1 infection have been addressed, there is a lack of studies focusing on the consequences of this delayed and narrowed immune response at the population level. To better explore these features, we evaluated the selection regimen in gag, pol and env gene fragments of HIV-1 during pediatric infection. We estimated the number of nonsynonymous substitutions (d(N)) and synonymous substitutions (d(S)) codon-by-codon, using the maximum likelihood method and a modified counting method. Notably, both methods indicated a similar intensity of selection (measure by mean d(N)/d(S) ratio) between children and adults. Additionally, sites under positive selection were equally distributed along HIV genes and the location of these sites was analogous between children and adults. Therefore, the selective regimen in HIV during pediatric infection is equally broad and intense likewise the observed in adults. Unexpectedly, our phylogenetic-based analysis enabled us to identify two regions in the env gene of HIV with distinct adaptive functions. The first region, located in the vicinity of V3 loop, contains sites that might increase viral fitness within-host during antibody attack and virus-cell interaction. The second region, restricted to amino acids 334-368 of Gp160, contains sites that might increase viral fitness during interhost transmission at the population level.

Strong HIV-1-specific T cell responses in HIV-1-exposed uninfected infants and neonates revealed after regulatory T cell removal

BACKGROUND

In utero transmission of HIV-1 occurs on average in only 3%-15% of HIV-1-exposed neonates born to mothers not on antiretroviral drug therapy. Thus, despite potential exposure, the majority of infants remain uninfected. Weak HIV-1-specific T-cell responses have been detected in children exposed to HIV-1, and potentially contribute to protection against infection. We, and others, have recently shown that the removal of CD4(+) CD25(+) T-regulatory (Treg) cells can reveal strong HIV-1 specific T-cell responses in some HIV-1 infected adults. Here, we hypothesized that Treg cells could suppress HIV-1-specific immune responses in young children.

METHODOLOGY/PRINCIPAL FINDINGS

We studied two cohorts of children. The first group included HIV-1-exposed-uninfected (EU) as well as unexposed (UNEX) neonates. The second group comprised HIV-1-infected and HIV-1-EU children. We quantified the frequency of Treg cells, T-cell activation, and cell-mediated immune responses. We detected high levels of CD4(+) CD25(+) CD127(-) Treg cells and low levels of CD4(+) and CD8(+) T cell activation in the cord blood of the EU neonates. We observed HIV-1-specific T cell immune responses in all of the children exposed to the virus. These T-cell responses were not seen in the cord blood of control HIV-1 unexposed neonates. Moreover, the depletion of CD4(+) CD25(+) Treg cells from the cord blood of EU newborns strikingly augmented both CD4(+) and CD8(+) HIV-1-specific immune responses.

CONCLUSIONS/SIGNIFICANCE

This study provides new evidence that EU infants can mount strong HIV-1-specific T cell responses, and that in utero CD4(+) CD25(+) T-regulatory cells may be contributing to the lack of vertical transmission by reducing T cell activation.

Effect of GB virus C on response to antiretroviral therapy in HIV-infected Brazilians

OBJECTIVES

GB virus C (GBV-C) infection is associated with delayed mortality in HIV-infected people in most, but not all, studies. Previous investigations of the effect of GBV-C viraemia on response to antiretroviral therapy (ART) were inconclusive. To determine the effect of GBV-C on ART, we retrospectively analysed plasma samples taken from patients in a prospective randomized clinical trial of ART in HIV-positive Brazilians.

METHODS

GBV-C viraemia was characterized by testing stored serum samples from 175 participants by reverse transcriptase-polymerase chain reaction (RT-PCR). Subjects were randomized to receive indinavir (n=59), zidovudine and lamivudine (n=58), or zidovudine, lamivudine and indinavir (n=58). The effect of GBV-C viraemia on the average change in HIV viral load and CD4 count following initiation of therapy was evaluated in a multiple regression analysis.

RESULTS

The prevalence of GBV-C viraemia was similar to that observed in previous studies (24%). HIV viral load decreased following ART to a significantly greater extent in patients with GBV-C viraemia (by 0.48 log(10) HIV-1 RNA copies/mL, P=0.009, adjusting for age, ART group, and baseline CD4 count). Although there was no significant difference in change in CD4 count between individuals with and without GBV-C viraemia overall, CD4 counts were higher following 48 weeks of therapy in GBV-C viraemic individuals receiving the least potent ART regimen (zidovudine and lamivudine) compared with those without GBV-C infection.

CONCLUSIONS

GBV-C viraemia is associated with an enhanced reduction of HIV viral load in response to ART. In this study of treatment-naive individuals during 48 weeks of follow up, patients with GBV-C viraemia had reductions in HIV viral load that were approximately 0.5 log copies/mL greater than those found in patients without GBV-C viraemia. This is similar to reductions observed with nucleoside reverse transcriptase inhibitors.

HIV-1 viremia during the first 28 weeks of pregnancy is not associated with mother-to-child transmission

It is currently recommended that antiretroviral prophylaxis to prevent mother-to-child transmission (MTCT) of HIV be initiated at 14 weeks of gestation. However, the relevance of early-gestation HIV viral load level for intrauterine MTCT is unknown. The objective of this study was to determine the relationship between prenatal maternal viral load and intrauterine MTCT. Records of HIV-infected pregnant women in two centers in Brazil, from 1999 to 2004 were analyzed. Three pregnancy periods were considered: earlier than 14 weeks, 14 to 27 6/7 weeks, and 28 weeks of gestation or more. Peripartum HIV exposure was also computed. Maximum viral load in each period was the measure of HIV exposure. Four hundred fifty-seven HIV-infected pregnant women were evaluated, but 53 were excluded. The MTCT rate was 0.49% (2/404-95% confidence interval (CI95) = 0.14-1.79%). Newborns were not breast-fed. Median viral load for the earlier-than-14-week period was 9,900 copies/mL (P25-75 1,000-50,775 copies/mL), 8,350 copies/mL (P25-75 707-42,000 copies/mL) for the 14 to 27 6/7-week period, and 435 copies/mL (P25-75 90-7,775 copies/mL) after the 28-week period. The peripartum median viral load was 400 copies/mL (P25-75 80-500 copies/mL). MTCT in mothers with VL > 1,000 copies/mL during the first 14 weeks (0.67%, 2/298) was not different from those with VL =1,000 copies/mL (0.0%, 0/96, P=1). Analogously, in the 14 to 27 6/7-week period, MTCT was similar in groups with VL higher (0.68%, 2/292) or lower (0%, 0/106) than 1,000 copies/mL (P=1). Regarding VL >1,000 copies/mL at 28-weeks-or-later and at peripartum periods, MTCT rates were 1.15% (2/173, P = 0.18) and 2.8% (2/71, P = 0.03), respectively. Intrauterine transmission does not seem to be influenced by HIV viremia during the first 28 weeks of pregnancy.

Analysis of the protease sequences of HIV-1 infected individuals after Indinavir monotherapy

BACKGROUND

Protease inhibitors (PI) are an important HIV-1 treatment tool. The HIV-1 genetic diversity as a result of antiretroviral exposure is a potential barrier to successful antiretroviral therapy.

OBJECTIVES

To describe the impact of the selective pressure of the PI Indinavir in the protease region of the pol gene of HIV-1.

STUDY DESIGN

We have examined the extent of protease sequence heterogeneity in previously antiretroviral drug naive HIV-1 infected individuals receiving Indinavir as monotherapy for at least 48 weeks.

RESULTS

Analysis based on the consensus of this group of sequences showed regions with higher and lower polymorphism. The degree of genetic variation was greater in regions less critical for the structure and function of the enzyme. To investigate the selective pressure imposed by drug therapy, we have analyzed the rate of synonymous (ds) and nonsynonymous (dn) substitutions. The three critical regions for enzyme activity showed ds/dn ratio >1. whereas other regions had ds/dn ratio <1. The detected amino acid mutations had a trend to be conservative, thus maintaining the physical chemical amino acid characteristics. Phylogenetic analysis established the presence of subtype B (n=38), subtype F (n=9), and B/F recombinants within the protease region of pol gene (n=3). More prevalent detected mutations, thought to contribute to antiretroviral resistance, were L63P (42%), L10I (35%), M36I (30%), V82A/T/F (26%).

CONCLUSIONS

A great deal of predicted cross-resistance between PIs was observed. Out of the 50 individuals, 34% were considered to have major mutations to Indinavir, and 66% had minor or no mutations to Indinavir. Viral loads were significantly higher among patients with major mutations, compared with patients minor/no mutations, although no differences in the CD4 counts were found. The viral load at baseline and nadir (week 4) was able to predict the group of individuals with greater chances of selecting drug resistance related mutations.

Brazilian Network for HIV Drug Resistance Surveillance (HIV-BResNet): a survey of chronically infected individuals

OBJECTIVE

To study the prevalence of HIV drug resistance mutations and subtype distribution in a Brazilian drug-naive population. Asymptomatic, drug-naive HIV-1-infected individuals were targeted in 13 voluntary counseling and testing centers spread around the country.

METHODS

Plasma viral RNA was extracted from 535 HIV-1-positive subjects. Protease (PR) and reverse transcriptase (RT) genomic regions were sequenced for subtype determination and analysis of drug resistance mutations.

RESULTS

Eight samples (2.24 %) showed primary mutations related to protease inhibitor (PI) resistance, eight (2.36%) to nucleoside reverse transcriptase inhibitors (NRTI) and seven (2.06%) to non-nucleoside reverse transcriptase inhibitors (NNRTI). Accessory mutations were found in the PR gene at the following positions: L63P/V/T/A/I [153/345 (44.3%)], M36I/L [149/345 (43.2%)], L10I/F/V [82/345 (23.8%)], V77I [60/345 (17.4%)], A71V/T [11/345 (3.2%)], K20M/R [10/345 (2.9%)], and V82I [4/345 (1.2%)]. Mutations known to be associated with reduced sensitivity to NRTI or NNRTI (V118I, E44D, K219R, T69A, and V75L) were found in a low prevalence (0.6-2.4%). A high proportion of the isolates from subtype C was found in the southern states. Subtype F-related viruses were the main non-B variant in the rest of the country.

CONCLUSIONS

Brazil has a low prevalence of drug-resistant strains circulating among recently diagnosed individuals. However, there was an increase in these rates compared with similar studies performed with samples collected in Brazil from 1996 to 1998. Continued surveys are required to detect trends in these rates, but routine genotypic testing in the drug-naive population prior to antiretroviral initiation is not required in Brazil.

Risk factors for incident HIV infection among anonymous HIV testing site clients in Santos, Brazil: 1996-1999

OBJECTIVES

To determine temporal trends in HIV infection and risk factors among persons seeking anonymous HIV testing in Santos, Brazil.

METHODS

Data and sera from persons testing for HIV from 1996 to 1999 were used. Exposures were abstracted from HIV testing risk assessments. Stored HIV-positive sera were tested to identify recently acquired HIV infection using a serologic testing algorithm for detecting recent HIV seroconversion (STARHS). Independent associations between exposures and recently acquired HIV infection were determined using multivariate analyses.

RESULTS

Overall, estimated HIV incidence was 2.0% (95% CI: 1.1-3.5) for the 4-year period: 1.2% (95% CI: 0.5-2.6) in women and 2.7% (95% CI: 1.3-5.0) in men. Incidence increased among women but remained stable among men. Exposures independently associated with incident infection included a history of sex work (OR= 5.4, 95% CI: 1.5-18.7), concurrent syphilis infection (OR =4.1, 95% CI: 1.4-11.9), anal sex (OR = 3.0, 95% CI: 1.3-7.1), and having an HIV-positive sexual partner (OR= 1.4, 95% CI: 1.1-1.9).

CONCLUSIONS

This study further demonstrates the public health utility of using the STARHS for the assessment of emerging trends in the HIV epidemic. Results from this study will help to target appropriate prevention strategies directed toward at-risk populations in Santos.

A specific subtype C of human immunodeficiency virus type 1 circulates in Brazil

OBJECTIVE

To characterize the subtype C strains of HIV type 1 that circulate in Brazil, especially those originated from the southern part of the country.

DESIGN AND METHODS

One hundred and twelve HIV-1-positive subjects had their plasma viral RNA extracted. Protease (PR) and reverse transcriptase (RT) genomic regions were polymerase chain reaction-amplified and sequenced for subtype determination. Subtype C strains were selected and compared to other strains of this subtype from the database, and specific amino acid signature patterns were searched.

RESULTS

Brazilian subtype C viruses form a very strong monophyletic group when compared to subtype C viruses from other countries and presented specific signature amino acids. Recombinants between subtype C and B viruses have been documented in areas of co-circulation. The incidence of primary PR and RT inhibitor resistance mutations in drug-naïve subjects was observed. An increasing number of secondary resistance mutations was also seen, some of which are characteristic of subtype C-related sequences.

CONCLUSIONS

Introduction of subtype C of HIV-1 in Brazil was likely a single event of one or a mixture of similarly related strains. Recombination between subtype C and B viruses is an ongoing process in the country. Primary and secondary drug resistance mutations were observed, although some of the secondary mutations could be associated with subtype C molecular signatures. Subtype-specific polymorphisms of PR and RT sequences found in this subtype C Brazilian variant might influence this emergence and have an impact on HIV treatment and on vaccine development in the country.

Estimating the length of the first antiretroviral therapy regiment durability in São Paulo, Brazil

Brazil was the first country to provide unrestricted, cost-free access to antiretroviral (ARV) medicine for AIDS treatment. However, there is little data about the benefits of such a policy for these patients. We evaluated the duration of benefit obtained with the introduction of ARVs, defined as the durability of the first ARV regiment. We reviewed the medical charts of patients attended from 1996-2000, at the outpatient clinics of the Federal University of São Paulo, Brazil. A total of 120 drug-naive HIV-1 infected patients were eligible to participate in the study. About half of the individuals (53%) presented with disease symptoms; 59% of them had CD(4) count below 200 cells/mm(3). Mean estimated duration of the benefit of therapy was 14.1 months. The most used regimen in this cohort was Zidovudine/3TC/Indinavir (26%), followed by Zidovudine/DDI (17%), and Zidovudine/3TC/Nelfinavir (13%). The most frequent cause of interruption of therapy was gastrointestinal intolerance. Use of treatment regimens with three drugs was more effective than with two drugs, but only for patients with CD(4)<200 cells/mm(3) or CV>100,000 copies RNA/mL. However, the use of triple therapy was associated with a significantly higher probability of reaching maximum viral suppression, during a longer period (p<0.05). The patients enrolled in the study benefitted from therapy for a limited time, after the introduction of double or triple antiretroviral therapy. The incidence of adverse events was significantly associated with loss of the benefits provided by the initial therapeutic regimen.

Prevalence of mutations related to HIV-1 antiretroviral resistance in Brazilian patients failing HAART

BACKGROUND

Current guidelines for antiretroviral (ARV) therapy recommend at least triple-drug combination, the so-called highly active antiretroviral therapy (HAART). Not all patients respond to HAART and the development of drug resistance remains one of the most serious obstacles to sustained suppression of HIV.

OBJECTIVE

In an attempt to correlate the HIV therapeutic failure with reverse transcriptase (RT) and protease resistance mutations, we describe the ARV resistance profile in patients failing HAART in Brazil. We studied 267 Brazilian HIV-1 infected patients failing HAART looking for mutations in RT and protease genes. The mutation profile of the viruses infecting these individuals were deduced and correlated to laboratorial parameters.

STUDY DESIGN

Two different HIV-1 genomic regions were targeted for PCR amplification, the protease (pro) and pol RT (palm finger region) genes. The mutations related to drug resistance in RT gene was analyzed using a line probe assay (LIPA(R)) and pro amino acids positions 82 and 90 were screened through RFLP using HincII restriction digestion.

RESULTS

There was strong correlation between the mutation in the pro and RT genes and therapeutic failure. The main mutation found in RT gene was the M184V (48%) followed by T69D/N (47%), T215Y/F (46%), M41L (39%), and L74V (7%). In the pro gene the main mutation found was L90M (26%) followed by dual substitution in L90M and V82A (6%). All mutations profiles matched very well with the patients drug regimen.

CONCLUSIONS

This study has shown that 84.7% of HIV infected subjects failing HAART for more than 3 months presented viral genomic mutations associated with drug resistance.

Induction of interleukin-10 by HIV antigens in peripheral mononuclear cells of health care workers after occupational exposure to HIV-1-positive blood

Evaluation of HIV-induced IL-2 production by peripheral blood mononuclear cells (PBMC) and HIV-specific T helper and cytotoxic T lymphocyte (CTL) responses in health care workers (HCW) occupationally exposed to HIV reveals a high rate of response to HIV among non-seroconverters. IL-10 is also known to interfere with HIV infection in vitro. To evaluate the induction of IL-10 by HIV antigens in HCW occupationally exposed to HIV, 18 HCW with percutaneous injury were enrolled in this study, 9 of them exposed to HIV-contaminated blood, and 9 exposed to HIV-negative blood. PBMC were incubated on plates coated with HIV-1 antigens, and IL-10 was measured in supernatants by ELISA. Five of nine HCW exposed to HIV-contaminated blood presented HIV-induced IL-10. Two of nine HCW exposed to HIV-negative source patients also had detectable levels of HIV-induced IL-10, one of them in the sample obtained on the day of accidental exposure. There was a relationship between the type of device involved in injury and IL-10 production. Individuals exposed to hollow needles or scalpels presented HIV-induced IL-10, whereas those exposed to solid needles and to digital puncture did not, suggesting a relationship between infectious load and IL-10. Although occupational exposure to HIV leads to a low rate of seroconversion, these individuals can develop an antigen-specific immune response characterized in our study by induction of IL-10 in PBMC in vitro.

Use of the sensitive/less-sensitive (detuned) EIA strategy for targeting genetic analysis of HIV-1 to recently infected blood donors

OBJECTIVE

To corroborate the validity of the recently developed sensitive/less sensitive (S/LS) dual enzyme immunoassay (EIA) strategy for the detection of recently infected individuals and to genetically analyze recently transmitted strains of HIV-1 in a US blood donor population.

DESIGN

The S/LS EIA strategy was used to identify 33 recently infected subjects among 281 enrolled HIV-1 seropositive blood donors (from a total of 410 HIV-1 infected subjects identified from 5 230 463 blood donations screened by participating US blood centers in 1995-1996).

METHODS

We analysed three host response and viral characteristics were associated with recent HIV-1 infection: rapidly increasing EIA optical density (OD) values, genetically homogeneous env gene quasispecies, and putative non-syncytium inducing env V3 loop sequences. The drug resistance genotypes of the recently transmitted strains were determined by DNA sequencing.

RESULTS

Increasing EIA OD values, clonal HIV-1 quasispecies and V3 loop sequences with inferred NSI phenotypes were generally detected in LS EIA non-reactive samples. Thirty-two subtype B and one CRF02_AG recombinant HIV-1 were detected. Genetic evidence for drug resistance to zidovudine (K70R) and non-nucleoside analog reverse transcriptase inhibitors (V108I) was detected in one strain each, and three other strains showed the presence of accessory protease inhibitor resistance mutations.

CONCLUSIONS

Immunologic and virologic results further substantiate the validity of the S/LS EIA strategy for the detection of recent infections and illustrate its use for targeting molecular and epidemiological investigations to incident cases identified from large cross-sectional screening programs, rather than the more costly and logistically difficult longitudinal studies.

Retrovirus infections in a sample of injecting drug users in Rio de Janeiro City, Brazil: prevalence of HIV-1 subtypes, and co-infection with HTLV-I/II

BACKGROUND

Retrovirus infections among injecting drug users (IDUs), a core at-risk population for both HIV-1 and HTLV-I/II infections in Brazil, were assessed within an ongoing cooperative research.

OBJECTIVE

The study assessed the seroprevalences of HIV-1 and HTLV-I/II infections, as well as the prevalence of HIV-1 subtypes in a sample of IDUs from Rio de Janeiro, Brazil. An attempt to evaluate HIV incidence was carried out using a dual 'sensitive/less sensitive' testing strategy.

STUDY DESIGN

Cross-sectional evaluation of 175 IDUs. Serostatus for HIV-1 and HTLV-I/II were established by enzyme-linked immunosorbent assays, and confirmed by western blot. The dual testing strategy aimed to estimate HIV-1 incidence rates. Differentiation between HTLV-I and -II was performed by western blot. DNA samples were polymerase chain reaction amplified by a nested protocol, and HIV-1 subtyping was determined by heteroduplex mobility assay.

RESULTS

Forty-six and 29 samples were found to be, respectively, positive for HIV-1 and HTLV-I/II, 15 of them co-infected by both viruses. Among HTLV-I/II-infected patients, 75.9% were infected by HTLV-I. Thirty-one HIV samples were identified as B subtype, with seven of them showing the typical "Brazilian B" pattern in the gp120 V3 loop, and ten were identified as F subtype. The use of less sensitive assays for HIV infection wrongly identified a deeply immunocompromised patient as an incident case.

CONCLUSION

Moderately high seroprevalences were found for both HIV-1 and HTLV-I/II infections, HIV-1/HTLV-I co-infections being of special concern. A non-statistically significant higher prevalence of F subtype was observed, when compared with the distribution of F/B subtypes among Brazilian patients from other exposure categories. No recent HIV-1 infections were detected, but a limitation of the "sensitive/less-sensitive" testing strategy was made evident.

HIV-1 subtypes among intravenous drug users from two neighboring cities in São Paulo State, Brazil

In order to assess the molecular epidemiology of HIV-1 in two neighboring cities located near the epicenter of the HIV-1 epidemics in Brazil (Santos and São Paulo), we investigated 83 HIV-1 strains obtained from samples collected in 1995 from intravenous drug users. The V3 through V5 region of the envelope of gp 120 was analyzed by heteroduplex mobility analysis. Of the 95 samples, 12 (12.6%) were PCR negative (6 samples from each group); low DNA concentration was the reason for non-amplification in half of these cases. Of the 42 typed cases from São Paulo, 34 (81%, 95% confidence limits 74.9 to 87.0%) were B and 8 (19%, 95% confidence limits 12.9 to 25.0%) were F, whereas of the 41 typed cases from Santos, 39 (95%, 95% confidence limits 91.6 to 98.4%) were B and 2 (5%, 95% confidence limits 1.6 to 8.4%) were C. We therefore confirm the relationship between clade F and intravenous drug use in São Paulo, and the presence of clade C in Santos. The fact that different genetic subtypes of HIV-1 are co-circulating indicates a need for continuous surveillance for these subtypes as well as for recombinant viruses in Brazil.

Surveillance of HIV-1 genetic subtypesand diversity in the US blood supply

BACKGROUND

Recent reports of variant (non-subtype B) HIV infections in US populations have raised concerns about the sensitivity of subtype B virus-based donor screening and diagnostic assays. This study was designed to determine the prevalence and genetic diversity of HIV subtypes in US blood donors over the last two decades.

STUDY DESIGN AND METHODS

Three groups were studied: hemophiliacs infected by clotting factor concentrates in the early 1980s (n = 49), blood donors retrospectively identified as being seropositive in 1985 (n = 97), and blood donors identified as seropositive between 1993 and 1996 (n = 405). Subtype assignment was based primarily on heteroduplex mobility analysis (HMA) of HIV-1 env, with DNA sequence confirmation of selected specimens. HIV peptide-based EIA serotyping was used to rule out HIV-2 and group O infections and to serotype HMA-refractory specimens.

RESULTS

Of 551 specimens, 535 (97%) were assigned subtypes; 532 (99%) of these were subtype B. Three postscreening donations (1%) were assigned non-B subtypes (2 A, 1 C). Two of these three donors were born in Africa; the third was born in the United States and reported no risk factors other than heterosexual activity. HMA distribution plots showed an increase in env diversity among HIV-1 group B strains over time.

CONCLUSION

The results support the need for continued surveillance of HIV subtype diversity and ongoing validation of the sensitivity of HIV diagnostic assays to non-B subtype infections.

Generation of intersubtype human immunodeficiency virus type 1 recombinants in env gene in vitro: influences in the biological behavior and in the establishment of productive infections

The occurrence of human immunodeficiency virus type 1 (HIV-1) recombinant genomes belonging to different subtypes is a common event in regions where more than two subtypes cocirculate. Although there are accumulating data toward an increase in the number of intersubtype recombinants, little has been addressed about the biological behavior of such mosaic genomes. This work reports the biological characterization of engineered in vitro HIV-1 intersubtype recombinants in the gp120 region. The recombinants possess the entire gp120 of B or F Brazilian isolates in the Z6 (subtype D) backbone. Here we show that this type of recombinant structure results in profound impairment to the establishment of productive infections in CD4-positive cells. The characterization of biological properties of those recombinant viruses demonstrated viral production occurring only during a transient peak early on infection and that they are not able to down-regulate the expression of CD4 receptor on the cell surface. We also report the phenotype reversion of one recombinant virus studied here, after 62 days in culture. Two amino acid substitutions in highly constant gp120 regions (C1 and C4) were identified in the revertant virus. The mutation occurring in the C4 region is localized near two amino acid residues critical for gp120/CD4 interaction. Based on these data, we suggest that failure in CD4 down-modulation by recombinant viruses can be due to a structural dysfunction of gp160 protein unable to block CD4 at the endoplasmic reticule. The possibilities that the establishment of latent infections can be directly related to the continuous expression of CD4 on the infected cell surface and that the occurrence of mutations in amino acid nearby residues critical for gp120/CD4 interaction can restore the fully productive infectious process are discussed.

HIV type 1 tat gene heteroduplex mobility assay as a tool to establish epidemiologic relationships among HIV type 1-infected individuals

Molecular biology techniques are increasingly used to study the molecular epidemiology of infectious diseases. Most of these methods are expensive and labor-intensive. The human immunodeficiency virus (HIV) has substantial genomic variation, such that HIVs from different individuals are genetically diverse, although mutation rates differ for distinct regions of the genome. Most studies of HIV linkage and molecular evolution have focused on env or gag regions. We show that heteroduplex mobility analysis of the first exon of the HIV tat gene provides a simple, rapid, inexpensive, and reliable discriminatory tool for the molecular differentiation of shared versus distinct HIV-1 quasispecies when epidemiologic relations need to be defined. tat, as a relatively conserved region, appears to be a better region than the more variable env region to establish HIV-1 epidemiological linkages.