Global HIV treatment programs need sensitive and affordable tests to monitor HIV drug resistance. We compared mutant detection by the oligonucleotide ligation assay (OLA), an economical and simple test, to massively parallel sequencing. Nonnucleoside reverse transcriptase inhibitor (K103N, V106M, Y181C, and G190A) and lamivudine (M184V) resistance mutations were quantified in blood-derived plasma RNA and cell DNA specimens by OLA and 454 pyrosequencing. A median of 1,000 HIV DNA or RNA templates (range, 163 to 1,874 templates) from blood specimens collected in Mozambique (n = 60) and Kenya (n = 51) were analyzed at 4 codons in each sample (n = 441 codons assessed). Mutations were detected at 75 (17%) codons by OLA sensitive to 2.0%, at 71 codons (16%; P = 0.78) by pyrosequencing using a cutoff value of ≥2.0%, and at 125 codons (28%; P < 0.0001) by pyrosequencing sensitive to 0.1%. Discrepancies between the assays included 15 codons with mutant concentrations of ∼2%, one at 8.8% by pyrosequencing and not detected by OLA, and one at 69% by OLA and not detected by pyrosequencing. The latter two cases were associated with genetic polymorphisms in the regions critical for ligation of the OLA probes and pyrosequencing primers, respectively. Overall, mutant concentrations quantified by the two methods correlated well across the codons tested (R2 > 0.8). Repeat pyrosequencing of 13 specimens showed reproducible detection of 5/24 mutations at <2% and 6/6 at ≥2%. In conclusion, the OLA and pyrosequencing performed similarly in the quantification of nonnucleoside reverse transcriptase inhibitor and lamivudine mutations present at >2% of the viral population in clinical specimens. While pyrosequencing was more sensitive, detection of mutants below 2% was not reproducible.
Our objective was to determine whether monitoring HIV-1 DNA concentration or new resistance mutations in peripheral blood mononuclear cells (PBMCs) during effective antiretroviral therapy (ART) predicts virologic failure. A retrospective analysis used blood specimens and clinical data from three nevirapine containing arms of a four-arm, open-label, randomized trial comparing ART regimens in HIV-1-infected children who had failed mono- or dual-nucleoside therapy. Sensitive assays compared cell-associated HIV-1 DNA concentrations and nevirapine (NVP) and lamivudine (3TC) resistance mutations in children with plasma HIV-1 RNA <400 copies(c)/ml who did or did not experience subsequent virologic failure. Forty-six children were analyzed through the last available follow-up specimen, collected at 48 (n=16) or 96 (n=30) weeks of ART. Thirty-five (76%) had sustained viral suppression and 11 (24%) had plasma viral rebound to ≥400 c/ml (virologic failure detected at a median of 36 weeks). HIV-1 DNA levels at baseline, 24, 48, and 96 weeks of ART were similar in children who did vs. did not experience virologic failure (p=0.82). HIV-1 DNA levels did not increase prior to viral rebound. NVP resistance mutations were detected in 91% of subjects in the failure group vs. 3% in the suppressed group (p <0.0001). Among nine evaluable children, NVP mutations were first detected prior to virologic failure in two (22%), at viral rebound in five (56%), and after failure in two (22%) children. HIV-1 DNA concentrations did not predict virologic failure in this cohort. New drug resistance mutations were detected in the PBMCs of a minority of virologically suppressed children who subsequently failed ART.
Single-dose nevirapine (sdNVP) given to prevent mother-to-child-transmission of HIV-1 selects NVP-resistance. Short-course zidovudine (ZDV) was hypothesized to lower rates of NVP-resistance. HIV-1 infected pregnant women administered sdNVP with or without short-course ZDV were assessed for HIV-1 mutations (K103N, Y181C, G190A, and V106M) prior to delivery and postpartum. Postpartum NVP-resistance was lower among 31 taking ZDV+sdNVP compared to 33 taking only sdNVP (35.5% vs 72.7%; χ2
P = .003). NVP mutants decayed to <2% in 24/35 (68.6%) at a median 6 months postpartum, with no differences based on ZDV use (logrank P = .99). Short-course ZDV was associated with reduced NVP-resistance mutations among women taking sdNVP.
In women, single-dose nevirapine for prophylaxis against mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1) selects for nevirapine-resistant HIV-1, which subsequently decays rapidly. We hypothesized that the selection, acquisition, and decay of nevirapine-resistant HIV-1 differs in infants, varying by the timing of HIV-1 infection.
We conducted a prospective, observational study of 740 Mozambican infants receiving single-dose nevirapine prophylaxis and determined the timing of infection and concentrations of nevirapine-resistant HIV-1 over time.
Infants with established in utero infection had a high rate (87.0%) of selection of nevirapine-resistant HIV-1 mutants, which rapidly decayed to undetectable levels. The few without nevirapine resistance received zidovudine with single-dose nevirapine and/or their mothers took alternative antiretroviral drugs. Infants with acute in utero infection had a lower rate of nevirapine-resistant HIV-1 (33.3%; P =.006, compared with established in utero infection), but mutants persisted over time. Infants with peripartum infection also had a lower rate of nevirapine-resistant HIV-1 (38.1%; P =.001, compared with established in utero infection) but often acquired 100% mutant virus that persisted over time (P =.017, compared with established in utero infection).
The detection and persistence of nevirapine-resistant HIV-1 in infants after single-dose nevirapine therapy vary by the timing of infection and the antiretroviral regimen. In infants with persistent high-level nevirapine-resistant HIV-1, nevirapine-based antiretroviral therapy is unlikely to ever be efficacious because of concentrations in long-lived viral reservoirs. However, the absence or decay of nevirapine-resistant HIV-1 in many infants suggests that nevirapine antiretroviral therapy may be effective if testing can identify these individuals.
Low-level HIV-1 replication may occur during antiretroviral therapy (ART) that suppresses plasma HIV-1 RNA to <50c/mL (suppressive ART). Antiretroviral drugs appear less effective in macrophages and monocytes compared to lymphocytes, both in vitro, and as implied in vivo by greater viral evolution observed during suppressive ART. Our objective was to examine sputum, which is rich in macrophages for evidence of increased HIV-1 replication compared to that in the blood during suppressive ART.
Cross sectional study during suppressive ART. Comparison of HIV-1 DNA sequences derived from induced sputa and peripheral blood mononuclear cells (PBMC).
Multiple sequences encoding HIV-1 reverse transcriptase, protease, and envelope were generated using single-genome-sequencing. Reverse transcriptase and protease sequences were analyzed for genotypic drug resistance. The evolutionary distances of env sequences from the inferred most recent common ancestor of infection were calculated and CXCR4 co-receptor usage was predicted.
970 bidirectional sequences from 11 individuals were analyzed. HIV-1 env and pol derived from sputa had greater frequency of drug resistance mutations (P = 0.05), evolutionary divergence (P = 0.004) and tendency for CXCR4 usage (P = 0.1) compared to viruses derived from PBMC.
The greater frequency of HIV-1 drug resistance mutations and divergence of HIV-1 env in sputa- compared to PBMC-derived viruses suggests greater HIV-1 replication in the respiratory tract compared to the blood. Characterization of viral evolution over time and by cell-type could identify cells that provide a sanctuary for low-level viral replication in the respiratory tract during suppressive ART.
drug resistance; highly active antiretroviral therapy; HIV-1; lung; macrophages; replication; sputum; virus
Antiretroviral treatment (ART) of HIV infection suppresses viral replication. Yet if ART is stopped, virus reemerges because of the persistence of infected cells. We evaluated the contribution of infected-cell proliferation and sites of proviral integration to HIV persistence. A total of 534 HIV integration sites (IS) and 63 adjacent HIV env sequences were derived from three study participants over 11.3 to 12.7 years of ART. Each participant had identical viral sequences integrated at the same position in multiple cells, demonstrating infected-cell proliferation. Integrations were overrepresented in genes associated with cancer and favored in 12 genes across multiple participants. Over time on ART, a greater proportion of persisting proviruses were in proliferating cells. HIV integration into specific genes may promote proliferation of HIV-infected cells, slowing viral decay during ART.
CCR5 antagonists are approved for treatment-experienced individuals, who are at risk of harboring both drug-resistant and CXCR4-utlizing (X4) HIV-1. If CXCR4 usage and drug resistance are linked, CCR5 antagonists may select for CXCR4-utlizing viruses resistant to antiretrovirals. Analysis of 117 individual viruses found that 69% of CXCR4-utlizing viruses versus 48% of R5 viruses had drug resistance mutations (P = 0.025). Linkage of X4 and drug resistance may limit the effectiveness of CCR5 antagonists.
We evaluated the feasibility of the oligonucleotide ligation assay (OLA), a specific, sensitive, and economical ligase-based point mutation assay designed to detect HIV-1 drug–resistance mutations at 12 codons of HIV-1 subtype B pol, for potential use in resource-poor settings.
Specimens from HIV-1–infected individuals collected by 7 international laboratories, including subtypes A, B, C, D, F, G, J, and recombinants AE and AG, were tested by the OLA developed for HIV-1 subtype B. Common polymorphisms that interfered with reactivity of the OLA were identified and modified probes designed and evaluated.
92.5% (2410) of 2604 codons in specimens from 217 individuals were successfully genotyped by the subtype B OLA. A high rate (range 8.3%–31.2%) of indeterminate results (negative OLA reaction for both mutant and wild type) was observed for 5 codons. Modified probes at reverse transcriptase codons 151 and 184 and protease codon 90 increased the rate of valid OLA to 96.1%.
The OLA designed for HIV-1 subtype B genotyped most pol codons in non-B subtypes from Asia and Africa but was improved by addition of several modified probes. International laboratories experienced in molecular techniques were able to perform the OLA.
HIV drug resistance; HIV-1 non-B subtypes; resistance testing; oligonucleotide ligation assay; minor genotypes; point mutation assay; dried blood spots
Oligonucleotide ligation assay (OLA) is a highly specific and relatively simple method to detect point mutations encoding HIV-1 drug-resistance, which can detect mutants comprising ≥2–5% of the viral population. Nevirapine (NVP), tenofovir (TDF) and lamivudine (3TC) are antiretroviral drugs (ARV) used worldwide for treatment of HIV infection and prevention of mother-to-child-transmission. Adapting the OLA to detect multiple mutations associated with HIV resistance to these ARV simultaneously would provide an efficient tool to monitor drug resistance in resource-limited settings. Known proportions of mutant and wild-type plasmids were used to optimize a multiplex OLA for detection of K103N, Y181C, K65R, and M184V in HIV subtypes B and C, and V106M and G190A in subtype C. Simultaneous detection of two mutations was impaired if probes annealed to overlapping regions of the viral template, but was sensitive to ≥2–5% when testing codons using non-overlapping probes. PCR products from HIV-subtype B and C-infected individuals were tested by multiplex-OLA and compared to results of single-codon OLA. Multiplex-OLA detected mutations at codon pairs 103/181, 106/190 and 65/184 reliably when compared to singleplex-OLA in clinical specimens. The multiplex-OLA is sensitive and specific and reduces the cost of screening for NVP, TDF and/or 3TC resistance.
HIV; antiretroviral drug resistance; oligonucleotide ligation assay; minority genotypes
Poor neurodevelopmental outcomes and recurrences of cutaneous lesions remain unacceptably frequent among survivors of neonatal herpes simplex virus (HSV) disease.
We enrolled neonates with HSV disease in two parallel, identical, double-blind, placebo-controlled studies. Neonates with central nervous system (CNS) involvement were enrolled in one study, and neonates with skin, eye, and mouth involvement only were enrolled in the other. After completing a regimen of 14 to 21 days of parenteral acyclovir, the infants were randomly assigned to immediate acyclovir suppression (300 mg per square meter of body-surface area per dose orally, three times daily for 6 months) or placebo. Cutaneous recurrences were treated with open-label episodic therapy.
A total of 74 neonates were enrolled — 45 with CNS involvement and 29 with skin, eye, and mouth disease. The Mental Development Index of the Bayley Scales of Infant Development (in which scores range from 50 to 150, with a mean of 100 and with higher scores indicating better neurodevelopmental outcomes) was assessed in 28 of the 45 infants with CNS involvement (62%) at 12 months of age. After adjustment for covariates, infants with CNS involvement who had been randomly assigned to acyclovir suppression had significantly higher mean Bayley mental-development scores at 12 months than did infants randomly assigned to placebo (88.24 vs. 68.12, P = 0.046). Overall, there was a trend toward more neutropenia in the acyclovir group than in the placebo group (P = 0.09).
Infants surviving neonatal HSV disease with CNS involvement had improved neurodevelopmental outcomes when they received suppressive therapy with oral acyclovir for 6 months. (Funded by the National Institute of Allergy and Infectious Diseases; CASG 103 and CASG 104 ClinicalTrials.gov numbers, NCT00031460 and NCT00031447, respectively.)
Insight concerning the switch in HIV-1 coreceptor use will lead to a better understanding of HIV-1 pathogenesis and host-virus dynamics. Predicting CXCR4 utilization by analyzing HIV-1 envelope consensus sequences is highly specific, but minority variants in the viral population are often missed resulting in low sensitivity. Commercial phenotypic assays are costly, and the development of sensitive in-house phenotypic assays to detect CXCR4-using HIV may not be feasible for some laboratories. A sensitive, inexpensive genotyping assay was developed to detect viral sequences associated with CXCR4-utilizing virus (X4). Codon-specific primer pairs were used to detect X4-associated codons at five positions in the HIV-1 envelope V3 loop (11, 13, 24, 25, and 32). Sixty plasma samples from HIV-1-infected individuals were analyzed by consensus sequencing and codon-specific PCR (CS-PCR). Forty-six of these were also phenotyped by Trofile or Enhanced Sensitivity Trofile (ESTA). CS-PCR detected X4 variants 17% more often than 11/24/25 consensus sequencing alone (n=60), 30% more often than Trofile (n=27), and in a limited data set, 16% more often than ESTA (n=19). CS-PCR combined with consensus sequencing had approximately 80% concordance with ESTA.
Background. Whether unique human immunodeficiency type 1 (HIV) genotypes occur in the genital tract is important for vaccine development and management of drug resistant viruses. Multiple cross-sectional studies suggest HIV is compartmentalized within the female genital tract. We hypothesize that bursts of HIV replication and/or proliferation of infected cells captured in cross-sectional analyses drive compartmentalization but over time genital-specific viral lineages do not form; rather viruses mix between genital tract and blood.
Methods. Eight women with ongoing HIV replication were studied during a period of 1.5 to 4.5 years. Multiple viral sequences were derived by single-genome amplification of the HIV C2-V5 region of env from genital secretions and blood plasma. Maximum likelihood phylogenies were evaluated for compartmentalization using 4 statistical tests.
Results. In cross-sectional analyses compartmentalization of genital from blood viruses was detected in three of eight women by all tests; this was associated with tissue specific clades containing multiple monotypic sequences. In longitudinal analysis, the tissues-specific clades did not persist to form viral lineages. Rather, across women, HIV lineages were comprised of both genital tract and blood sequences.
Conclusions. The observation of genital-specific HIV clades only in cross-sectional analysis and an absence of genital-specific lineages in longitudinal analyses suggest a dynamic interchange of HIV variants between the female genital tract and blood.
HIV; female genital tract; compartmentalization; viral lineages; monotypic HIV; genetic distances; uterine cervix; phylogenetics
Non-invasive diagnostic assays to evaluate mitochondrial toxicity could have significant clinical utility for HIV-infected individuals on antiretroviral therapy (ART).
This study compared the ratio of mitochondrial to nuclear DNA determined by quantitative PCR to the ratio of mitochondrial to nuclear-encoded proteins by flow cytometry, in peripheral blood mononuclear cells from 73 HIV-infected individuals with and without risk factors for mitochondrial toxicity.
PCR detected similar mitochondrial/nuclear DNA in HIV-infected individuals without a history of ART, and those receiving ART with lipodystrophy, lipoatrophy or a history of suspected lactic acidosis. However, the ratio was significantly greater in ART-untreated compared to those receiving either stavudine or didanosine. In contrast, flow cytometry did not detect any differences in mitochondrial/nuclear protein (1). There was no correlation between the assays (rho = −0.05, p = 0.65).
Assessment of the mitochondrial/nuclear DNA ratio by quantitative PCR performed better than the mitochondrial/nuclear-encoded protein ratio by flow cytometry to detect adverse effects of nucleoside analogues on mitochondria.
HIV; Antiretroviral Therapy; Mitochondrial Toxicity; Flow Cytometry; Quantitative PCR; Diagnostics
Cervical shedding of HIV-1 DNA may influence HIV-1 sexual transmission. HIV-1 DNA was detected in 250/316 (80%) and 207/259 (79%) cervical cytobrush specimens from 56 United States (US) and 80 Kenyan women, respectively. Plasma HIV-1 RNA concentration was associated with increased HIV-1 DNA shedding among US and Kenyan women. Kenyan women had higher cervicovaginal concentrations of pro-inflammatory interleukins (IL)-1β, IL-6, IL-8 and anti-inflammatory secretory leukocyte protease inhibitor (SLPI) compared to US women (all p < 0.01). HIV-1 DNA shedding was associated with increased concentrations of IL-1β and IL-6 and lower SLPI among US women, but not Kenyan women.
Bacterial vaginosis has been associated with genital HIV-1 shedding; however, the effect of specific vaginal bacterial species has not been assessed. We tested cervicovaginal lavage from HIV-1-seropositive women for common Lactobacillus species: L. crispatus, L. jensenii, and seven BV-associated species: BVAB1, BVAB2, BVAB3, Leptotrichia, Sneathia, Megasphaera, and Atopobium spp. using quantitative PCR. We used linear and Poisson regression to evaluate associations between vaginal bacteria and genital HIV-1 RNA and DNA. Specimens from 54 U.S. (310 visits) and 50 Kenyan women (137 visits) were evaluated. Controlling for plasma viral load, U.S. and Kenyan women had similar rates of HIV-1 RNA (19% of visits vs. 24%; IRR=0.95; 95% CI 0.61, 1.49) and DNA shedding (79% vs. 76%; IRR=0.90; 0.78, 1.05). At visits during antiretroviral therapy (ART), the likelihood of detection of HIV-1 RNA shedding was greater with BVAB3 (IRR=3.16; 95% CI 1.36, 7.32), Leptotrichia, or Sneathia (IRR=2.13; 1.02, 4.72), and less with L. jensenii (IRR=0.39; 0.18, 0.84). At visits without ART, only L. crispatus was associated with a lower likelihood of HIV-1 RNA detection (IRR=0.6; 0.40, 0.91). Vaginal Lactobacillus species were associated with lower risk of genital HIV-1 shedding, while the presence of certain BV-associated species may increase that risk.
454 pyrosequencing, a massively parallel sequencing (MPS) technology, is often used to study HIV genetic variation. However, the substantial mismatch error rate of the PCR required to prepare HIV-containing samples for pyrosequencing has limited the detection of rare variants within viral populations to those present above ~1%. To improve detection of rare variants, we varied PCR enzymes and conditions to identify those that combined high sensitivity with a low error rate. Substitution errors were found to vary up to 3-fold between the different enzymes tested. The sensitivity of each enzyme, which impacts the number of templates amplified for pyrosequencing, was shown to vary, although not consistently across genes and different samples. We also describe an amplicon-based method to improve the consistency of read coverage over stretches of the HIV-1 genome. Twenty-two primers were designed to amplify 11 overlapping amplicons in the HIV-1 clade B gag-pol and env gp120 coding regions to encompass 4.7 kb of the viral genome per sample at sensitivities as low as 0.01-0.2%.
Among 30 human immunodeficiency virus type 1 (HIV-1)–infected women who received single-dose nevirapine (NVP), 17 (57%) had NVP-resistant HIV-1 detected in breast milk. NVP resistance in breast milk persisted for at least 8 months postpartum and was apparently transmitted to at least 1 infant. NVP resistance was detected less often in women who also received zidovudine.
Understanding how HIV-1 persists during effective antiretroviral therapy (ART) should inform strategies to cure HIV-1 infection. We hypothesize that proliferation of HIV-1-infected cells contributes to persistence of HIV-1 infection during suppressive ART. This predicts that identical or monotypic HIV-1 DNA sequences will increase over time during ART. We analyzed 1,656 env and pol sequences generated following single-genome amplification from the blood and sputum of six individuals during long-term suppressive ART. The median proportion of monotypic sequences increased from 25.0% prior to ART to 43.2% after a median of 9.8 years of suppressive ART. The proportion of monotypic sequences was estimated to increase 3.3% per year (95% confidence interval, 2.3 to 4.4%; P < 0.001). Drug resistance mutations were not more common in the monotypic sequences, arguing against viral replication during times with lower antiretroviral concentrations. Bioinformatic analysis found equivalent genetic distances of monotypic and nonmonotypic sequences from the predicted founder virus sequence, suggesting that the relative increase in monotypic variants over time is not due to selective survival of cells with viruses from the time of acute infection or from just prior to ART initiation. Furthermore, while the total HIV-1 DNA load decreased during ART, the calculated concentration of monotypic sequences was stable in children, despite growth over nearly a decade of observation, consistent with proliferation of infected CD4+ T cells and slower decay of monotypic sequences. Our findings suggest that proliferation of cells with proviruses is a likely mechanism of HIV-1 DNA persistence, which should be considered when designing strategies to eradicate HIV-1 infection.
Compare the risk of HIV-drug-resistance in women stopping suppressive nelfinavir-(NFV) or nevirapine (NVP)-based-ART after pregnancy.
Specimens collected after stopping ART were tested for drug-resistance by an oligonucleotide ligation assay (OLA) and consensus sequencing. When postpartum drug-resistance was detected, specimens obtained at study entry and during ART were evaluated.
16/38 women with ART-induced suppression of viral replication suspended ART postpartum. Resistance mutations were detected in 75% who stopped NFV- and 50% who stopped NVP-ART. M184V, associated with 3TC-resistance, was more frequent among those randomized to NFV- compared to NVP-ART (6/8 vs. 1/8; P=0.04), and NNRTI-resistance was detected in 4/8 stopping NVP-ART.
HIV-drug-resistance was frequently observed among women who stopped suppressive NVP- or NFV-ART postpartum. This suggests that NFV-ART may have suboptimal potency; that staggering discontinuation of NVP-ART may be warranted; and/or ART-adherence may be lax in women who choose to stop ART postpartum.
HIV-1; Antiretroviral drug resistance; Antiretroviral discontinuation; Pregnancy; Oligonucleotide ligation assay (OLA); Minority genotypes; Nelfinavir; Nevirapine; Lamivudine; Zidovudine
To determine the association between antenatal CD4+ cell count and development of viral drug resistance following use of peripartum nevirapine (NVP) for perinatal HIV prevention.
Secondary analysis of data from previously conducted randomized control trial.
HIV positive pregnant women.
We analyzed data from a clinical trial of single-dose tenofovir/emtricitabine (TDF/FTC) to reduce viral drug resistance associated with peripartum NVP. The trial population was categorized according to antenatal CD4+ cell count (200–350 cells/uL, 351–500 cells/uL, and >500 cells/uL).
Main outcome measures
Relative risk for acquiring drug resistance—determined by consensus sequencing and oligonucleotide ligation assay (OLA)—was estimated using multivariable logistic regression.
Of 397 study participants, 119 (30%) had a CD4+ count of 200–350 cells/uL, 135 (34%) had a CD4+ count of 351–500 cells/uL, and 143 (36%) had a CD4+ count >500 cells/uL. Among women receiving no intervention, risk for drug resistance appeared to increase as CD4+ cell count decreased. Participants with CD4+ cell counts of 200–350 cells/uL randomized to the study arm had the lowest risk, suggesting higher efficacy of the intervention within this stratum. These results were consistent at two and six weeks, regardless of how drug resistance was measured.
Women with CD4+ cell counts of 200–350 cells/uL may be at increased risk for viral drug resistance following use of peripartum NVP. Given the high prevalence of NVP resistance and the clear benefits of treatment, antiretroviral therapy should be initiated among pregnant women with CD4+ cell counts ≤ 350 cells/uL.
HIV; antiretroviral therapy; non-nucleoside reverse transcriptase inhibitor; resistance; prevention of mother-to-child transmission; CD4+ cell count
Recent in vitro studies suggest that acyclovir may directly inhibit HIV-1 replication and can select for a specific HIV-1 reverse transcriptase mutation (V75I) with concomitant loss of an anti-HIV-1 effect. We tested for HIV-1 genotypic resistance at reverse transcriptase codon 75 in plasma from 168 HIV-1 infected persons from Botswana, Kenya, Peru, and the US taking daily acyclovir or valacyclovir for between 8 weeks and 24 months. No V75I cases were detected (95% confidence interval: 0-2.2%). These prospective in vivo studies suggest that standard-dose acyclovir or valacyclovir does not select for HIV-1 resistance.
HSV-2; HIV-1 resistance; V75I
Recent in vitro studies suggest that acyclovir may directly inhibit HIV-1 replication and can select for a specific HIV-1 reverse transcriptase mutation (V75I) with concomitant loss of an anti-HIV-1 effect. We tested for HIV-1 genotypic resistance at reverse transcriptase codon 75 in plasma from 168 HIV-1–infected persons from Botswana, Kenya, Peru, and the United States taking daily acyclovir or valacyclovir for between 8 weeks and 24 months. No V75I cases were detected (95% confidence interval, 0%–2.2%). These prospective in vivo studies suggest that standard-dose acyclovir or valacyclovir does not select for HIV-1 resistance.
To evaluate minority variant drug resistance mutations detected by the oligonucleotide ligation assay (OLA) but not consensus sequencing among subjects with primary HIV-1 infection.
Observational, longitudinal cohort study. Consensus sequencing and OLA were performed on the first available specimens from 99 subjects enrolled after 1996. Survival analyses, adjusted for HIV-1 RNA levels at the start of antiretroviral (ARV) therapy, evaluated the time to virologic suppression (HIV-1 RNA<50 copies/mL) among subjects with minority variants conferring intermediate or high-level resistance.
Consensus sequencing and OLA detected resistance mutations in 5% and 27% of subjects, respectively, in specimens obtained a median of 30 days after infection. Median time to virologic suppression was 110 (IQR 62–147) days for 63 treated subjects without detectable mutations, 84 (IQR 56–109) days for ten subjects with minority variant mutations treated with ≥3 active ARVs, and 104 (IQR 60–162) days for nine subjects with minority variant mutations treated with <3 active ARVs (p = .9). Compared to subjects without mutations, time to virologic suppression was similar for subjects with minority variant mutations treated with ≥3 active ARVs (aHR 1.2, 95% CI 0.6–2.4, p = .6) and subjects with minority variant mutations treated with <3 active ARVs (aHR 1.0, 95% CI 0.4–2.4, p = .9). Two subjects with drug resistance and two subjects without detectable resistance experienced virologic failure.
Consensus sequencing significantly underestimated the prevalence of drug resistance mutations in ARV-naïve subjects with primary HIV-1 infection. Minority variants were not associated with impaired ARV response, possibly due to the small sample size. It is also possible that, with highly-potent ARVs, minority variant mutations may be relevant only at certain critical codons.
Pregnancy may lead to increases in HIV-1 RNA levels postpartum. The AIDS Clinical Trials Group (ACTG) A5150 study was designed to characterize the incidence of viral load rebound during the immediate 24 weeks postpartum and explore factors associated with viral load rebound.
We enrolled pregnant women in the United States who were ≥13 years of age, between 22 to 30 weeks gestation, and who planned to be on stable highly active antiretroviral therapy (HAART) for ≥8 weeks predelivery and to continue this therapy after delivery for the duration of the study. Choice of antiretrovirals (ARVs) was determined by the primary HIV provider. Viral load rebound was defined as an increase of ≥0.7 log10 (5-fold) from the average of the weeks 34 and 36 gestation viral loads to week 24 postpartum or an absolute increase to >500 copies/mL for those with viral load <50 copies/mL.
Eighty-four women enrolled for postpartum follow-up. Sixty-three had follow-up and viral load obtained through week 24 postpartum. Overall, 18/63 (28.6%; 95% confidence interval [CI], 17.9–41.4) met criteria for viral load rebound. Nineteen of the 63 women made changes or discontinued their ARV regimen prior to week 24 postpartum. For those who remained on stable ARVs, rebound occurred in 8/44 (18.2%; 95% CI, 8.2–32.7) compared with 10/19 (52.6%; 95% CI, 28.9–75.5) who did not remain on a stable ARV regimen.
In the early postpartum period, HIV-1–infected women commonly have increases in viral load. Unplanned changes in ARV regimens and discontinuations of treatment are frequent.
HIV-1 viral load; lopinavir; nelfinavir; pharmacokinetics; pregnancy; ritonavir