Search tips
Search criteria

Results 1-25 (70)

Clipboard (0)

Select a Filter Below

Year of Publication
more »
Document Types
1.  Estimation of HIV Incidence Using Multiple Biomarkers 
American Journal of Epidemiology  2013;177(3):264-272.
The incidence of human immunodeficiency virus (HIV) is the rate at which new HIV infections occur in populations. The development of accurate, practical, and cost-effective approaches to estimation of HIV incidence is a priority among researchers in HIV surveillance because of limitations with existing methods. In this paper, we develop methods for estimating HIV incidence rates using multiple biomarkers in biological samples collected from a cross-sectional survey. An advantage of the method is that it does not require longitudinal follow-up of individuals. We use assays for BED, avidity, viral load, and CD4 cell count data from clade B samples collected in several US epidemiologic cohorts between 1987 and 2010. Considering issues of accuracy, cost, and implementation, we identify optimal multiassay algorithms for estimating incidence. We find that the multiple-biomarker approach to cross-sectional HIV incidence estimation corrects the significant deficiencies of currently available approaches and is a potentially powerful and practical tool for HIV surveillance.
PMCID: PMC3626051  PMID: 23302151
acquired immunodeficiency syndrome; algorithms; cross-sectional studies; HIV; incidence; models, statistical
2.  Use of a Multifaceted Approach to Analyze HIV Incidence in a Cohort Study of Women in the United States: HIV Prevention Trials Network 064 Study 
The Journal of Infectious Diseases  2012;207(2):223-231.
Background. Reliable methods for estimating the incidence of human immunodeficiency virus (HIV) infection are needed to monitor the epidemic, identify at-risk populations, and evaluate HIV prevention strategies. We used a multifaceted approach to estimate HIV incidence in the HIV Prevention Trials Network (HPTN) 064 study.
Methods. The HPTN 064 study enrolled 2067 HIV-seronegative women and 32 HIV-seropositive women with no prior HIV infection diagnosis. Women were followed for up to 12 months. HIV incidence estimates were based on (1) detection of acute HIV infection, (2) documentation of HIV seroconversion, and (3) detection of recent HIV infection, using a multiassay algorithm (MAA).
Results. Two women had acute HIV infection at enrollment, 4 seroconverted, and 2 were identified as recently infected at enrollment using the MAA. The annual HIV incidence estimate based on acute infection at enrollment (2.52% [95% confidence interval {CI}, .17%–9.33%], using a 14-day window period) was higher than the estimate based on seroconversion (0.24% [95% CI, .07%–.62%]; P = .027). Incidence estimates obtained using the MAA at enrollment and at the end of study were 0.25% (95% CI, .03%–.93%) and 0.13% (95% CI, .006%–.76%), respectively.
Conclusions. We detected a high frequency of acute infection at enrollment. Cross-sectional HIV incidence estimates obtained using the MAA were similar to the longitudinal estimate based on HIV seroconversion.
Clinical Trials Registration. NCT00995176.
PMCID: PMC3532822  PMID: 23129758
HIV-1; women; United States; incidence
3.  Correction: Association of pol Diversity with Antiretroviral Treatment Outcomes among HIV-Infected African Children 
PLoS ONE  2013;8(12):10.1371/annotation/dd945f7c-c50b-461d-ab38-15e8b0966458.
PMCID: PMC3873195
4.  Correction: Association of pol Diversity with Antiretroviral Treatment Outcomes among HIV-Infected African Children 
PLoS ONE  2013;8(12):10.1371/annotation/6937ccda-2f54-430d-94d0-b71d1ecc5273.
PMCID: PMC3861509
5.  HIV-1 Transmission during Early Antiretroviral Therapy: Evaluation of Two HIV-1 Transmission Events in the HPTN 052 Prevention Study 
PLoS ONE  2013;8(9):e71557.
In the HPTN 052 study, transmission between HIV-discordant couples was reduced by 96% when the HIV-infected partner received suppressive antiretroviral therapy (ART). We examined two transmission events where the newly infected partner was diagnosed after the HIV-infected partner (index) initiated therapy. We evaluated the sequence complexity of the viral populations and antibody reactivity in the newly infected partner to estimate the dates of transmission to the newly infected partners. In both cases, transmission most likely occurred significantly before HIV-1 diagnosis of the newly infected partner, and either just before the initiation of therapy or before viral replication was adequately suppressed by therapy of the index. This study further strengthens the conclusion about the efficacy of blocking transmission by treating the infected partner of discordant couples. However, this study does not rule out the potential for HIV-1 transmission to occur shortly after initiation of ART, and this should be recognized when antiretroviral therapy is used for HIV-1 prevention.
PMCID: PMC3782474  PMID: 24086252
6.  Stavudine (d4T) concentrations in women receiving post-partum antiretroviral treatment and their breastfeeding infants 
First-line antiretroviral treatment regimens in resource-limited settings used in breastfeeding mothers often include stavudine (d4T). Limited data describing d4T concentrations in breast milk are available. We analyzed d4T concentrations in 52 mother-infant pairs using ultra-performance liquid chromatography-tandem mass spectrometry (lower limit of quantification: 5 ng/ml in plasma, 20 ng/ml in breast milk). Median (interquartile range) d4T concentrations were 86 (36–191) ng/ml in maternal plasma, 151 (48–259) ng/ml in whole milk, 190 (58–296) ng/ml in skim milk, and <5 (<5-<5) ng/ml in infant plasma. While d4T is concentrated in breast milk relative to maternal plasma, the infant d4T dose received from breast milk is very small and not clinically significant.
PMCID: PMC3404155  PMID: 22614899
stavudine concentrations; breast milk; mother-to-child transmission; HIV
7.  Analysis of nevirapine resistance mutations in cloned HIV-1 variants from HIV-infected Ugandan infants using a single step amplification-sequencing method (AmpliSeq) 
AIDS research and human retroviruses  2008;24(9):1209-1213.
We analyzed genetic linkage of nevirapine (NVP) resistance mutations and the genetic complexity of HIV-1 variants in Ugandan infants who were HIV-infected despite single dose (SD) prophylaxis. Plasma samples were obtained from six HIV-infected infants who had two or more NVP resistance mutations detected by population sequencing (ViroSeq). ViroSeq PCR products were cloned and transformed, and a single step amplification-sequencing reaction (AmpliSeq) was used to analyze NVP resistance mutations in cloned HIV-1 variants directly from bacterial colonies. Fifty clones were analyzed for each infant sample. This analysis revealed numerous NVP resistance mutations not detected by population sequencing, genetically-linked NVP resistance mutations, and a high degree of genetic complexity at codons that influence NVP susceptibility.
PMCID: PMC2562759  PMID: 18788912
8.  Efficiency of CCR5 Coreceptor Utilization by the HIV Quasispecies Increases over Time, But Is Not Associated with Disease Progression 
CCR5 is the primary coreceptor for HIV entry. Early after infection, the HIV viral population diversifies rapidly into a quasispecies. It is not known whether the initial efficiency of the viral quasispecies to utilize CCR5 is associated with HIV disease progression or if it changes in an infected individual over time. The CCR5 and CXCR4 utilization efficiencies (R5-UE and X4-UE) of the HIV quasispecies were examined using a pseudovirus, single-round infection assay for samples obtained from known seroconverters from Rakai district, Uganda (n=88). Initial and longitudinal R5-UE values were examined to assess the association of R5-UE with HIV disease progression using multivariate Cox proportional hazard models. Longitudinal samples were analyzed for 35 seroconverters who had samples available from multiple time points. There was no association between initial or longitudinal changes in R5-UE and the hazard of HIV disease progression (p=0.225 and p=0.942, respectively). In addition, R5-UE increased significantly over time after HIV seroconversion (p<0.001), regardless of HIV subtype or the emergence of CXCR4-tropic virus. These data demonstrate that the R5-UE of the viral quasispecies early in HIV infection is not associated with disease progression, and that R5-UE levels increase in HIV-infected individuals over time.
PMCID: PMC3292754  PMID: 21663455
9.  Comparison of a High-Resolution Melting Assay to Next-Generation Sequencing for Analysis of HIV Diversity 
Journal of Clinical Microbiology  2012;50(9):3054-3059.
Next-generation sequencing (NGS) has recently been used for analysis of HIV diversity, but this method is labor-intensive, costly, and requires complex protocols for data analysis. We compared diversity measures obtained using NGS data to those obtained using a diversity assay based on high-resolution melting (HRM) of DNA duplexes. The HRM diversity assay provides a single numeric score that reflects the level of diversity in the region analyzed. HIV gag and env from individuals in Rakai, Uganda, were analyzed in a previous study using NGS (n = 220 samples from 110 individuals). Three sequence-based diversity measures were calculated from the NGS sequence data (percent diversity, percent complexity, and Shannon entropy). The amplicon pools used for NGS were analyzed with the HRM diversity assay. HRM scores were significantly associated with sequence-based measures of HIV diversity for both gag and env (P < 0.001 for all measures). The level of diversity measured by the HRM diversity assay and NGS increased over time in both regions analyzed (P < 0.001 for all measures except for percent complexity in gag), and similar amounts of diversification were observed with both methods (P < 0.001 for all measures except for percent complexity in gag). Diversity measures obtained using the HRM diversity assay were significantly associated with those from NGS, and similar increases in diversity over time were detected by both methods. The HRM diversity assay is faster and less expensive than NGS, facilitating rapid analysis of large studies of HIV diversity and evolution.
PMCID: PMC3421787  PMID: 22785188
10.  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 
PLoS ONE  2013;8(2):e55525.
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.
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.
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.
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.
PMCID: PMC3577851  PMID: 23437058
11.  Identification of Ugandan HIV Type 1 Variants with Unique Patterns of Recombination in pol Involving Subtypes A and D 
Most HIV-1 infections in Uganda are caused by subtypes A and D. The prevalence of recombination and the sites of specific breakpoints between these subtypes have not been reported. HIV-1 pol sequences encoding protease (amino acids 1-99) and reverse transcriptase (amino acids 1-324) from 102 pregnant Ugandan women were analyzed by the Recombinant Identification Program, SimPlot, and examination of phylogenetically informative sites to identify sites of recombination between sequence segments belonging to different subtypes. Thirteen percent (13 of 102) of the pol sequences contained strong evidence of recombination between subtypes A and D. At least nine different patterns of recombination were observed. Five women infected with a recombinant virus transmitted the recombinant virus perinatally. In this population-based study, intersubtype recombinants were common. The large number of different types of pol recombinants identified suggests that recombination occurs readily in the pol region. Perinatal transmission of the recombinant viruses demonstrates their evolutionary stability.
PMCID: PMC2573392  PMID: 12015904
12.  Analysis of Genetic Linkage of HIV From Couples Enrolled in the HIV Prevention Trials Network 052 Trial 
The Journal of Infectious Diseases  2011;204(12):1918-1926.
Background. The HIV Prevention Trials Network (HPTN) 052 trial demonstrated that early initiation of antiretroviral therapy (ART) reduces human immunodeficiency virus (HIV) transmission from HIV-infected adults (index participants) to their HIV-uninfected sexual partners. We analyzed HIV from 38 index-partner pairs and 80 unrelated index participants (controls) to assess the linkage of seroconversion events.
Methods. Linkage was assessed using phylogenetic analysis of HIV pol sequences and Bayesian analysis of genetic distances between pol sequences from index-partner pairs and controls. Selected samples were also analyzed using next-generation sequencing (env region).
Results. In 29 of the 38 (76.3%) cases analyzed, the index was the likely source of the partner’s HIV infection (linked). In 7 cases (18.4%), the partner was most likely infected from a source other than the index participant (unlinked). In 2 cases (5.3%), linkage status could not be definitively established.
Conclusions. Nearly one-fifth of the seroconversion events in HPTN 052 were unlinked. The association of early ART and reduced HIV transmission was stronger when the analysis included only linked events. This underscores the importance of assessing the genetic linkage of HIV seroconversion events in HIV prevention studies involving serodiscordant couples.
PMCID: PMC3209811  PMID: 21990420
13.  Association of recent HIV infection and in utero HIV-1 transmission: Findings from the PEPI-Malawi trial 
AIDS (London, England)  2011;25(11):1357-1364.
We previously developed a multi-assay algorithm (MAA) to identify recent HIV infection that includes the BED-Capture Enzyme Immunoassay, an avidity assay based on the Genetic Systems HIV-1/HIV-2+O Enzyme Immunoassay, CD4 cell count, and HIV viral load. We used this MAA to evaluate the association between recent maternal HIV infection and in utero transmission of HIV.
Plasma samples were collected at delivery from 2,561 HIV-infected women in the PEPI-Malawi trial. The MAA described above was used to identify women with recent HIV infection. Logistic regression models assessed association between recent HIV infection and in utero HIV transmission (defined as a positive infant HIV DNA test at birth).
Seventy-three women were identified as recently infected using the MAA. Those women were younger and had lower parity than women who were identified as not recently infected using the MAA (P<0.0001 for age and parity). The frequency of in utero HIV transmission was 17.8% among women identified as recently infected, compared to 6.7% among women identified as not recently infected (13/73 vs. 166/2488, P=0.001). In a multivariate model, three factors were independently associated with in utero HIV transmission: recent infection (adjusted odds ratio [AOR]: 2.49, 95% CI: 1.30–4.78, P=0.006), log10 HIV viral load at delivery (AOR: 2.01, 95% CI: 1.60–2.51, P<0.0001), and younger age (per 10 year increase, AOR: 0.66, 95% CI: 0.43–0.93, P=0.02).
Results obtained using a MAA suggest that recent maternal HIV acquisition is strongly associated with in utero HIV transmission, independent of HIV viral load at delivery.
PMCID: PMC3263827  PMID: 21572305
HIV; incidence; multiassay algorithm; mother-to-child transmission; Malawi
14.  Use of Dried-Blood-Spot Samples and In-House Assays To Identify Antiretroviral Drug Resistance in HIV-Infected Children in Resource-Constrained Settings ▿  
Journal of Clinical Microbiology  2011;49(12):4077-4082.
Monitoring HIV drug resistance is an important component of the World Health Organization's global HIV program. HIV drug resistance testing is optimal with commercially available clinically validated test kits using plasma; however, that type of testing may not be feasible or affordable in resource-constrained settings. HIV genotyping from dried blood spots (DBS) with noncommercial (in-house) assays may facilitate the capture of HIV drug resistance outcomes in resource-constrained settings but has had varying rates of success. With in-house assays for HIV reverse transcriptase, we evaluated the yield of genotyping DBS samples collected from HIV-infected children who were enrolled in two clinical trials conducted in sub-Saharan Africa (median HIV viral load, 5.88 log10 HIV RNA copies/ml; range, 4.04 to 6.99). Overall, HIV genotypes were obtained for 94 (89.5%) of 105 samples tested (95% and 84% from clinical trials #1 and #2, respectively); however, successful analysis of 15 (16.1%) of the 94 samples required repeat testing using a different set of primers on previously synthesized cDNA. The yield of genotyping was lower on the DBS that were stored suboptimally from clinical trial #2 (56% versus 88% for optimally stored). Concordance with plasma genotypes derived using a clinically validated, commercial kit-based assay (ViroSeq HIV-1 genotyping system) was also assessed in a subset of children with paired testing. For 34 samples with paired DBS and plasma genotypes, there was 100% concordance for major drug resistance mutations. DBS genotyping using in-house assays provides an alternative for antiretroviral drug resistance testing in children in resource-constrained regions but may require region-specific optimization before widespread use.
PMCID: PMC3232965  PMID: 21956987
15.  Initiation of Antiretroviral Treatment in Women After Delivery Can Induce Multiclass Drug Resistance in Breastfeeding HIV-Infected Infants 
HIV-infected breastfeeding infants acquired multi-class drug resistance (MCR) after their mothers started highly active antiretroviral therapy (HAART). MCR was more frequent in infants whose mothers started HAART by 6 months post-partum or were exclusively breastfeeding when they reported HAART use.
Background. The World Health Organization currently recommends initiation of highly active antiretroviral therapy (HAART) for human immunodeficiency virus (HIV)–infected lactating women with CD4+ cell counts <350 cells/μL or stage 3 or 4 disease. We analyzed antiretroviral drug resistance in HIV-infected infants in the Post Exposure Prophylaxis of Infants trial whose mothers initiated HAART postpartum (with a regimen of nevirapine [NVP], stavudine, and lamivudine). Infants in the trial received single-dose NVP and a week of zidovudine (ZDV) at birth; some infants also received extended daily NVP prophylaxis, with or without extended ZDV prophylaxis.
Methods. We analyzed drug resistance in plasma samples collected from all HIV-infected infants whose mothers started HAART in the first postpartum year. Resistance testing was performed using the first plasma sample collected within 6 months after maternal HAART initiation. Categorical variables were compared by exact or trend tests; continuous variables were compared using rank-sum tests.
Results. Multiclass resistance (MCR) was detected in HIV from 11 (29.7%) of 37 infants. Infants were more likely to develop MCR infection if their mothers initiated HAART earlier in the postpartum period (by 14 weeks vs after 14 weeks and up to 6 months vs after 6 months, P = .0009), or if the mother was exclusively breastfeeding at the time of HAART initiation (exclusive breastfeeding vs mixed feeding vs no breastfeeding, P = .003).
Conclusions. postpartum maternal HAART initiation was associated with acquisition of MCR in HIV-infected breastfeeding infants. The risk was higher among infants whose mothers initiated HAART closer to the time of delivery or were still exclusively breastfeeding when they first reported HAART use.
PMCID: PMC3070029  PMID: 21460326
16.  Experience in international clinical research: the HIV Prevention Trials Network 
Clinical investigation  2011;1(12):1609-1618.
The HIV Prevention Trials Network (HPTN) is supported by the NIH to conduct randomized clinical trials to assess the efficacy of HIV prevention strategies and technologies to reduce HIV transmission between adults. A special focus of attention is on the use of antiretroviral drugs to prevent HIV transmission, both by reducing infectiousness among HIV-infected persons taking combination antiretroviral therapy (cART) and also by reducing susceptibility among HIV-uninfected persons taking antiretrovirals for pre-exposure prophylaxis. Studies may be developmental in nature to assess novel ideas for interventions or for assessing trial feasibility. However, pivotal efficacy trials to test HIV-specific prevention strategies and technologies are the main HPTN priority. Examples include a major protocol investigating the impact of expanded testing and linkage to care on HIV surveillance indicators in the USA (HPTN 065). Another protocol is addressing similar issues while also investigating how combinations of prevention approaches are best deployed to make a community-level impact in southern Africa (HPTN 071). HPTN 068 is evaluating a novel conditional cash transfer structural intervention to increase school completion rates in young girls and thereby reduce their HIV risk. Studies outside the US address the epidemic in most at-risk populations and include an assessment of opiate agonist therapy to reduce risk of HIV seroconversion among injection drug users (HTPN 058), methods to increase HIV testing rates (HTPN 043), as well as methods for reducing high-risk behaviors, and increasing adherence to cART in HIV-infected individuals (HPTN 062 and HPTN 063, respectively). The recent HPTN 052 study demonstrated that a 96% reduction in HIV transmission could be achieved between serodiscordant sexual partners by providing the infected partners with cART at a CD4+ cell count (350–550/µl) above the level that would usually qualify them for therapy in low- and middle-income countries. The immediate relevance to public health policy showcased in these trials is a paradigm for the HPTN: design and conduct of clinical trials using available licensed tools that can be rapidly translated for implementation (‘Prevention NOW!’).
PMCID: PMC3281583  PMID: 22348195
developing country; HIV/AIDS; prevention; randomized clinical trial; research collaboration; research infrastructure
18.  The Effect of Sample Handling on Cross Sectional HIV Incidence Testing Results 
PLoS ONE  2011;6(10):e25899.
To determine if mishandling prior to testing would make a sample from a chronically infected subject appear recently infected when tested by cross-sectional HIV incidence assays.
Serum samples from 31 subjects with chronic HIV infection were tested. Samples were subjected to different handling conditions, including incubation at 4°C, 25°C and 37°C, for 1, 3, 7 or 15 days prior to testing. Samples were also subjected to 1,3, 7 and 15 freeze-thaw cycles prior to testing. Samples were tested using the BED capture enzyme immuno assay (BED-CEIA), Vironostika-less sensitive (V-LS), and an avidity assay using the Genetic Systems HIV-1/HIV-2 plus O EIA (avidity assay).
Compared to the sample that was not subjected to any mishandling conditions, for the BED-CEIA, V-LS and avidity assay, there was no significant change in test results for samples incubated at 4°C or 25°C prior to testing. No impact on test results occurred after 15 freeze-thaw cycles. A decrease in assay results was observed when samples were held for 3 days or longer at 37°C prior to testing.
Samples can be subjected up to 15 freeze-thaw cycles without affecting the results the BED-CEIA, Vironostika-LS, or avidity assays. Storing samples at 4°C or 25°C for up to fifteen days prior to testing had no impact on test results. However, storing samples at 37°C for three or more days did affect results obtained with these assays.
PMCID: PMC3202521  PMID: 22046249
19.  Effect of Acyclovir on HIV-1 Set Point among HSV-2 Seropositive Persons during Early HIV-1 Infection 
The Journal of infectious diseases  2010;202(5):734-738.
We evaluated whether acyclovir suppression during human immunodeficiency virus type 1 (HIV-1) acquisition reduces HIV-1 set point, increases CD4 cell counts, and selects reverse-transcriptase mutations among 76 HIV-1 seroconverters identified in a placebo-controlled trial of twice-daily acyclovir (400 mg) for the prevention of HIV acquisition in herpes simplex virus type 2 (HSV-2)–seropositive persons (HIV Prevention Trials Network study 039). We found no significant difference in plasma HIV-1 RNA levels (P<.30)or CD4 cell counts (P<.85) between the acyclovir and placebo recipients. V75I and other mutations in HIV-1 reverse transcriptase reported from in vitro acyclovir studies were not observed. In conclusion, acyclovir suppression during HIV-1 seroconversion and the subsequent 6 months does not affect HIV-1 set point.
PMCID: PMC2964878  PMID: 20649426
Acyclovir; HIV-1 seroconversion; HIV-1 viral set point; HSV-2
20.  Analysis of Drug Resistance in Children Receiving Antiretroviral Therapy for Treatment of HIV-1 Infection in Uganda 
We analyzed drug resistance in HIV-infected Ugandan children who received antiretroviral therapy in a prospective, observational study (2004–2006); some children had prior single-dose nevirapine (sdNVP) exposure. Children received stavudine (d4T), lamivudine (3TC), and nevirapine (NVP); treatment was continued if they were clinically and immunologically stable. Samples with >1,000 copies/ml HIV RNA were analyzed by using the ViroSeq HIV Genotyping System (ViroSeq). Subtype A and D pretreatment samples also were analyzed with the LigAmp assay (for K103N, Y181C, and G190A). ViroSeq results were obtained for 74 pretreatment samples (35 from sdNVP-exposed children (median age, 19 months) and 39 from sdNVP-unexposed children (median age, 84 months). This included 39 subtype A, 22 subtype D, 1 subtype C, and 12 inter-subtype recombinant samples. One sample had nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance, one had nucleoside reverse transcriptase inhibitor (NRTI) resistance, and three had protease inhibitor (PI) resistance. Y181C was detected by using LigAmp in five pretreatment samples [four (14.8%) of 37 samples from sdNVP-exposed children, one (4.2%) of 24 samples from children without prior sdNVP exposure; p = 0.35]. Among children who were not virally suppressed at 48 weeks of treatment, all 12 tested had NNRTI resistance, as well as resistance to 3TC and emtricitibine (FTC); three had resistance to other NRTIs. Seven of those children had a ViroSeq result at 96 weeks of treatment; four of the seven acquired resistance to additional NRTIs by 96 weeks. In Uganda, clinically and immunologically stable children receiving nonsuppressive antiretroviral treatment regimens are at risk for development of drug resistance.
PMCID: PMC2875950  PMID: 20455758
Dosing frequency is an important determinant of regimen effectiveness.
To compare efficacy of once-daily (QD) versus twice-daily (BID) antiretroviral therapy, we randomized HIV-1 positive, treatment-naïve, patients to lopinavir/ritonavir (LPV/r) 400/100 mg BID (n=160) or LPV/r 800/200 mg QD (n=161), plus either emtricitabine 200 mg QD and extended-release stavudine (d4T-XR) 100 mg QD, or tenofovir 300 mg QD. Randomization was stratified by screening HIV-1 RNA
Subjects were 78% male, 33% Hispanic, and 34% black. 82% of subjects completed the study, and 71% remained on initially assigned dose schedule. Probability of SVR did not differ significantly for the BID vs. QD comparison, with an absolute proportional difference (95% confidence interval [CI]) of 0.03 (−0.07, 0.12). The comparison depended on the screening RNA stratum (p=0.038); in the higher RNA stratum, the probability (95% CI) of SVR was significantly better in the BID arm: 0.89 (0.79, 0.94) compared to 0.76 (0.64, 0.84) in the QD arm; difference of 0.13 (0.01, 0.25). LPV trough plasma concentrations were higher with BID dosing. Adherence to prescribed doses of LPV/r was 90.6% in the QD arm versus 79.9% in the BID arm (p<0.001).
Although subjects assigned to QD regimens had better adherence, overall treatment outcomes were similar to the BID regimens. Subjects with HIV-1 RNA ≥100,000 copies/mL had better SVR on BID regimens at 48 weeks, suggesting a possible advantage in this setting for more frequent dosing.
PMCID: PMC2833234  PMID: 20192725
HIV; clinical trials; adherence; lopinavir; pharmacokinetics
AIDS (London, England)  2010;24(4):557-561.
Single-dose nevirapine (sdNVP) can reduce the risk of HIV vertical transmission. We assessed risk factors for NVP resistance in plasma and breast milk from sdNVP-exposed Ugandan women.
Samples were analyzed using the Roche AMPLICOR HIV-1 Monitor Test Kit, v1.5, and the ViroSeq HIV-1 Genotyping System. NVP concentrations were determined by liquid chromatography with tandem mass spectroscopy.
HIV genotypes (plasma and breast milk) were obtained for 30 women 4 weeks after sdNVP (HIV subtypes: 15A, 1C, 12D, 2 recombinant). NVP resistance was detected in 12 (40%) of 30 breast milk samples. There was a non-significant trend between detection of NVP resistance in breast milk and plasma (p=0.06). There was no association of HIV resistance in breast milk with median maternal pre-NVP viral load or CD4 cell count, median breast milk viral load at 4 weeks, breast milk sodium >10 mmol/L, HIV subtype, or concentration of NVP in breast milk or plasma.
NVP resistance was frequently detected in breast milk 4 weeks after sdNVP exposure. In this study, we were unable to identify specific factors associated with breast milk NVP resistance.
PMCID: PMC3065236  PMID: 20057308
nevirapine; HIV-1; breast milk; Uganda; vertical transmission; nevirapine resistance
We evaluated use of the ARCHITECT® HIV Ag/Ab Combo assay (HIV Combo; Abbott Diagnostics; available for sale outside of the U.S. only) for detection of acute HIV infection.
Samples were obtained from a behavioral intervention study (EXPLORE). HIV-uninfected men who have sex with men were enrolled and tested for HIV infection every 6 months. Samples from seroconverters collected at their last seronegative visit (n=217) were tested individually using two HIV RNA assays. Samples with detectable HIV RNA were classified as acute and were tested with HIV Combo. Samples from the enrollment visit (n=83) and the time of HIV seroconversion (n=219) were tested with HIV Combo as controls.
Twenty-one (9.7%) samples from the last seronegative visit had detectable HIV RNA and were classified as acute. HIV Combo was positive for 13 (61.9%) of the acute samples. Samples not detected by HIV Combo had viral loads of 724 to 15,130 copies/ml. Expected results were obtained for positive and negative controls tested with HIV Combo.
HIV Combo detected nearly two-thirds of acute HIV infections identified in this high-risk population by non-pooled, HIV RNA assays. HIV Combo may be useful for high-throughput screening to identify individuals with acute HIV infection.
PMCID: PMC2744045  PMID: 19506484
acute infection; HIV-1; HIV Ag/Ab Combo assay
We screened 150 individuals from two recent seroconverter cohorts and found that six (4%) had CXCR4-using viruses. Clonal analysis of these six individuals, along with a seventh individual identified during clinical care as a recent seroconverter, revealed the presence of both X4- and dual-tropic variants in these recently infected adults. The ability of individual CXCR4-using variants to infect cells expressing CD4/CXCR4 or CD4/CCR5 varied dramatically. These data demonstrate that virus populations in some newly infected individuals can consist of either heterogeneous populations containing both CXCR4-using and CCR5-tropic viruses, or homogeneous populations containing only CXCR4-using viruses. The presence of CXCR4-using viruses at early stages of infection suggests that testing for viral tropism before using CCR5 antagonists may be important even in persons with known recent infection. The presence of CXCR4-using viruses in a subset of newly infected individuals could impact the efficacies of vaccine and microbicide strategies that target CCR5-tropic viruses.
PMCID: PMC2827835  PMID: 19678765
The Pediatric infectious disease journal  2013;32(4):10.1097/INF.0b013e31827f44ee.
The HPTN 046 trial evaluated the efficacy of extended infant nevirapine (NVP) administration for prevention of HIV transmission through breastfeeding. Infants received daily NVP to 6 weeks of age. HIV-uninfected infants (the intent-to-treat group) received daily NVP or placebo up to 6 months of age. We analyzed emergence of NVP resistance in infants who acquired HIV-infection despite prophylaxis.
HIV genotyping was performed using the ViroSeq HIV Genotyping System. Medians and proportions were used to summarize data. Two-sided Fisher’s exact tests were used to evaluate associations between categorical variables.
NVP resistance was detected in 12 (92.3%) of 13 infants who were HIV-infected by 6 weeks and in seven (28%) of 25 infants who were HIV-uninfected at 6 weeks and HIV-infected at 6 months of age (6/8=75% in the NVP arm, 1/17=5.9% in the placebo arm, P=0.001). Among those 25 infants, 4 had mothers who initiated an antiretroviral (ARV) treatment regimen by 6 months postpartum. In all 4 cases, the treatment regimen included a non-nucleoside reverse transcriptase inhibitor (NVP or efavirenz). NVP resistance was detected in all four of those infants by 6 months of age (4/4=100%). In contrast, only three (14.2%) of the remaining 21 HIV-infected infants whose mothers did not initiate ARV treatment developed NVP resistance (P=0.003).
Extended NVP prophylaxis significantly increased the risk of NVP resistance in infants who acquired HIV infection after 6 weeks of age. Treatment of maternal HIV infection was also associated with emergence of NVP resistance in HIV-infected, breastfed infants.
PMCID: PMC3826537  PMID: 23249916
Nevirapine resistance; prevention of mother-to-child transmission; extended nevirapine; HIV

Results 1-25 (70)