Background. Immunogenetic correlates of resistance to HIV-1 in HIV-1–exposed seronegative (HESN) individuals with consistently high exposure may inform HIV-1 prevention strategies. We developed a novel approach for quantifying HIV-1 exposure to identify individuals remaining HIV-1 uninfected despite persistent high exposure.
Methods. We used longitudinal predictors of HIV-1 transmission in HIV-1 serodiscordant couples to score HIV-1 exposure and define HESN clusters with persistently high, low, and decreasing risk trajectories. The model was validated in an independent cohort of serodiscordant couples. We describe a statistical tool that can be applied to other HESN cohorts to identify individuals with high exposure to HIV-1.
Results. HIV-1 exposure was best quantified by frequency of unprotected sex with, plasma HIV-1 RNA levels among, and presence of genital ulcer disease among HIV-1–infected partners and by age, pregnancy status, herpes simplex virus 2 serostatus, and male circumcision status among HESN participants. Overall, 14% of HESN individuals persistently had high HIV-1 exposure and exhibited a declining incidence of HIV-1 infection over time.
Conclusions. A minority of HESN individuals from HIV-1–discordant couples had persistent high HIV-1 exposure over time. Decreasing incidence of infection in this group suggests these individuals were selected for resistance to HIV-1 and may be most appropriate for identifying biological correlates of natural host resistance to HIV-1 infection.
Assays to determine cross-sectional HIV incidence misclassify some individuals with nonrecent HIV infection as recently infected, overestimating HIV incidence. We analyzed factors associated with false-recent misclassification in five African countries. Samples from 2197 adults from Botswana, Kenya, South Africa, Tanzania, and Uganda who were HIV infected >12 months were tested using the (1) BED capture enzyme immunoassay (BED), (2) avidity assay, (3) BED and avidity assays with higher assay cutoffs (BED+avidity screen), and (4) multiassay algorithm (MAA) that includes the BED+avidity screen, CD4 cell count, and HIV viral load. Logistic regression identified factors associated with misclassification. False-recent misclassification rates and 95% confidence intervals were BED alone: 7.6% (6.6, 8.8); avidity assay alone: 3.5% (2.7, 4.3); BED+avidity screen: 2.2% (1.7, 2.9); and MAA: 1.2% (0.8, 1.8). The misclassification rate for the MAA was significantly lower than the rates for the other three methods (each p<0.05). Misclassification rates were lower when the analysis was limited to subtype C-endemic countries, with the lowest rate obtained for the MAA [0.8% (0.2, 1.9)]. Factors associated with misclassification were for BED alone: country of origin, antiretroviral treatment (ART), viral load, and CD4 cell count; for avidity assay alone: country of origin; for BED+avidity screen: country of origin and ART. No factors were associated with misclassification using the MAA. In a multivariate model, these associations remained significant with one exception: the association of ART with misclassification was completely attenuated. A MAA that included CD4 cell count and viral load had lower false-recent misclassification than the BED or avidity assays (alone or in combination). Studies are underway to compare the sensitivity of these methods for detection of recent HIV infection.
Prophylactic cotrimoxazole is recommended for infants born to HIV-infected mothers. However, cotrimoxazole may increase the risk of severe anemia or neutropenia.
We compared the proportion of HIV-exposed uninfected (HIV-EU) infants experiencing incident severe anemia (and separately, severe neutropenia) between a prospective cohort receiving prophylactic cotrimoxazole from 1 to 6 months vs. infants from two prior trials who did not receive cotrimoxazole. Infants were from rural and urban communities in southern Botswana.
A total of 1705 HIV-EU infants were included. Among these 645 (37.8%) were fed with iron-supplemented formula from birth. Severe anemia developed in 87 (5.1%) infants, and severe neutropenia in 164 (9.6%) infants. In an analysis stratified by infant feeding method, there were no significant differences in the risk of severe anemia by prophylactic cotrimoxazole exposure–risk difference, −0.69% (95% confidence interval [CI] −2.1 to 0.76%). Findings were similar in multivariable analysis, adjusted odds ratio (aOR) 0.35 (95% CI 0.07 to 1.65). There were also no significant differences observed for severe neutropenia by cotrimoxazole exposure, risk difference 2.0% (95% CI −1.3 to 5.2%) and aOR 0.80 (95% CI 0.33 to 1.93).
Severe anemia and severe neutropenia were infrequent among HIV-exposed uninfected infants receiving cotrimoxazole from 1–6 months of age. Concerns regarding hematologic toxicity should not limit the use of prophylactic cotrimoxazole in HIV-exposed uninfected infants.
ClinicalTrials.gov Registration Numbers
NCT01086878 (http://clinicaltrials.gov/show/NCT01086878), NCT00197587 (http://clinicaltrials.gov/show/NCT00197587), and NCT00270296 (http://clinicaltrials.gov/show/NCT00270296).
Nucleoside analogue reverse transcriptase inhibitors are an integral component of combination antiretroviral treatment regimens. However, their ability to inhibit polymerase-γ has been associated with several mitochondrial toxicities, including potentially life-threatening lactic acidosis. A total of 650 antiretroviral-naive adults (69% female) initiated combination antiretroviral therapy (cART) and were intensively screened for toxicities including lactic acidosis as part of a 3-year clinical trial in Botswana. Patients were categorized as no lactic acidosis symptoms, minor symptoms but lactate <4.4 mmol/liter, and symptoms with lactate ≥4.4 mmol/liter [moderate to severe symptomatic hyperlactatemia (SH) or lactic acidosis (LA)]. Of 650 participants 111 (17.1%) developed symptoms and/or laboratory results suggestive of lactic acidosis and had a serum lactate drawn; 97 (87.4%) of these were female. There were 20 events, 13 having SH and 7 with LA; all 20 (100%) were female (p<0.001). Cox proportional hazard analysis limited to the 451 females revealed that having a higher baseline BMI was predictive for the development of SH/LA [aHR=1.17 per one-unit increase (1.08–1.25), p<0.0001]. Ordered logistic regression performed among all 650 patients revealed that having a lower baseline hemoglobin [aOR=1.28 per one-unit decrease (1.1–1.49), p=0.002] and being randomized to d4T/3TC-based cART [aOR=1.76 relative to ZDV/3TC (1.03–3.01), p=0.04] were predictive of the symptoms and/or the development of SH/LA. cART-treated women in sub-Saharan Africa, especially those having higher body mass indices, should receive additional monitoring for SH/LA. Women presently receiving d4T/3TC-based cART in such settings also warrant more intensive monitoring.
Clinical laboratories in Botswana have relied entirely on the reference intervals for normal immunohaematological values provided by manufacturers' kits and textbooks.
The aim of this study was to determine the means, medians, 2.5th and 97.5th percentile reference intervals, for normal immunohaematological values in healthy adults in Botswana.
A total of 261 healthy participants comprising 126 men (48%) and 135 (52%) women were enrolled in the southern part of Botswana, and immunological and haematological laboratory parameters were measured.
The mean age was 28.8 (95% Confidence Interval [CI] 27.7–29.8) years, with a median of 27 years and a range 18–66 years. The mean haemoglobin level was significantly lower for women (12.4 g/dL; 95% CI 12.1% – 12.7%) than men (15.1 g/dL; 95% CI 14.9% – 15.3%). The women's haemoglobin reference values (9.0 g/dL – 15.0 g/dL) levels were lower than observed in predominantly White populations (12.0 g/dL – 16.0 g/dL), but comparable with regional consensus reference intervals (9.5 g/dL – 15.8 g/dL) recently defined for East and Southern Africa.
The established values provide an important tool for patient management and could influence decisions on inclusion of participants and adverse events in clinical trials conducted locally.
Risk factors associated with preeclampsia in HIV-infected women remain largely unknown. Systemic angiogenic imbalance contributes to preeclampsia in HIV-uninfected women, but changes in angiogenic markers after HAART initiation have not been studied.
The Mma Bana study randomized 560 HIV-infected, HAART-naive pregnant women with CD4 counts ≥ 200 cells/mm3 between 26–34 weeks gestation to lopinavir/ritonavir/zidovudine/lamivudine or abacavir/zidovudine/lamivudine. Another 170 participants with CD4 counts < 200 cells/mm3 initiated nevirapine/zidovudine/lamivudine between 18–34 weeks gestation. Characteristics of 11 women who developed preeclampsia were compared with the remaining722 Mma Bana participants who delivered, using logistic regression. Plasma samples drawn at HAART initiation and one month later from 60 women without preeclampsia and at HAART initiation for all11 preeclamptic women were assayed for placental growth factor (PlGF) and soluble FMS toll-like tyrosine kinase-1 (sFlt-1),
Pre-HAART viral load > 100,000 copies/ml was associated with preeclampsia (OR 5.8; 95% CI 1.8, 19.4; p = 0.004). Median pre-HAART PlGF level was lower and sFLT-1 was higher in women who developed preeclampsia versus those who did not (130 vs 992 pg/ml, p=0.001; 17.5 vs 9.4 pg/ml, p=0.03, respectively). In multivariate analysis, PlGF and viral load remained significantly associated with preeclampsia. No significant changes in angiogenic factors were noted after 1 month of HAART treatment among non-preeclamptic women.
Pre-HAART viral load > 100,000 copies/ml and PlGF predicted preeclampsia among women starting HAART in pregnancy. Among non-preeclamptic women, HAART treatment did not significantly alter levels of PlGF or sFlt-1 one month into treatment.
HIV-1; viral load; pregnancy; preeclampsia; HAART
Few studies have compared the programmatic effectiveness of the recommended strategies of antenatal highly-active antiretroviral therapy (HAART) and zidovudine for prevention of mother-to-child transmission (MTCT). We prospectively followed infants (93% formula-fed) whose mothers who took either HAART (258 infants) or zidovudine (170 infants) during pregnancy in the Botswana national program. Overall, 10 infants (2.5%) acquired HIV— 9 infants in the zidovudine group (5.5%, 95%CI 2.6-10.2%) and 1 infant in the HAART group (0.4%, 95%CI 0.0-2.2%). Maternal HAART was associated with decreased MTCT (P=0.001) and improved HIV-free survival (P=0.040) compared with zidovudine (with or without single-dose nevirapine) in a programmatic setting.
Nucleoside reverse-transcriptase inhibitors (NRTIs) are a major component of combination antiretroviral therapy (cART) worldwide but they have been associated with mitochondrial toxicities, with one of the most significant being lactic acidosis. In southern Africa, being female and overweight (BMI > 25) as well as receiving d4T and/or ddI-based cART are risk factors for the development of this potentially life-threatening complication. It is challenging in many resource-limited settings to obtain reliable serum lactate measurements while screening for the presence of lactic acidosis. Point-of-care devices, however, are now available that provide simple, accurate measurements of serum lactate levels at relatively low cost. The objective of this study was to assess the agreement of the portable (Accutrend™ handheld) lactate analyzer to the conventional laboratory system for obtaining serum lactate.
Eighty two “at-risk” cART-treated adults were evaluated, having their lactate levels tested in parallel using both modalities.
The mean (range) lactate level for the portable device was 2.28 (0.9-5.0) compared to 1.96 (0.7-5.4) using the conventional method. There was a strong correlation (p<0.05) between the portable device and the conventional means with a Pearson correlation coefficient of 0.92 [95% CI: 0.88-0.95]. The mean bias was 0.33 [95% CI: -0.39-1.04], with the portable device having slightly higher values.
The use of a portable lactate device provides an accurate and user-friendly means of screening at-risk patients for the presence of lactic acidosis in resource-limited settings with limited laboratory capacity.
HIV/AIDS; lactic acidosis; Botswana; Point-of-care devices; Complications of combination antiretroviral therapy (cART)
(See the editorial commentary by Kourtis, on pages 493–4.)
Background. Protease inhibitor (PI)-based highly active antiretroviral therapy (HAART) use in pregnancy has been associated with preterm deliveries in some observational studies.
Methods. HIV-infected, HAART-naive pregnant women with CD4+ counts ≥200 cells/mm3 were randomized between 26 and 34 weeks gestation to lopinavir/ritonavir/zidovudine/lamivudine (PI group) or abacavir/zidovudine/lamivudine (NRTI group) in a clinical trial to prevent mother-to-child HIV transmission. Risk factors for preterm delivery (<37 weeks) and differences by randomization arm were evaluated for live infants by logistic regression.
Results. Preterm delivery rates were higher among 267 women in the PI group than 263 women in the NRTI group (21.4% vs 11.8%, P = .003). PI-based HAART was the most significant risk factor for preterm delivery [odds ratio = 2.03, 95% confidence interval 1.26–3.27, P = .004]. Mean change in maternal body mass index (BMI) 1 month after HAART initiation was lower in the PI group (P < .001); however, this was not significantly associated with preterm delivery. Neither infant hospitalizations nor mortality through 6 months of life differed by maternal regimen.
Conclusions. PI-based HAART was associated with increased preterm delivery but not increased infant hospitalizations or mortality in a clinical trial setting. The association between PI use and lower increase in BMI in late pregnancy warrants further study.
Maternal highly-active antiretroviral therapy (HAART) reduces mother-to-child HIV transmission (MTCT), but may increase the risk for infant anemia.
The incidence of first severe anemia (Grade 3 or 4, Division of AIDS 2004 Toxicity Table) was assessed among HIV-uninfected infants in the Mashi and Mma Bana MTCT prevention trials in Botswana. Severe anemia rates were compared between 3 groups: infants exposed to maternal HAART in utero and during breastfeeding and 1 month of postnatal zidovudine (HAART-BF); infants exposed to maternal zidovudine (ZDV) in utero, 6 months of postnatal ZDV, and breastfeeding (ZDV-BF); and infants exposed to maternal ZDV in utero, 1 month of postnatal ZDV, and formula-feeding (ZDV-FF).
A total of 1719 infants were analyzed— 691 HAART-BF, 503 ZDV-BF, and 525 ZDV-FF. Severe anemia was detected in 118 infants (7.4%). By 6 months, 12.5% of HAART-BF infants experienced severe anemia, compared with 5.3% of ZDV-BF (P<0.001) and 2.5% of ZDV-FF infants (P<0.001). In adjusted analysis, HAART-BF infants were at greater risk of severe anemia than ZDV-BF or ZDV-FF infants (adjusted odds ratios 2.6 and 5.8, respectively; P < 0.001). Most anemias were asymptomatic and improved with iron/multivitamin supplementation and cessation of ZDV exposure. However, 11 infants (0.6% of all infants) required transfusion for symptomatic anemia. Microcytosis and hypochromia were common among infants with severe anemia.
Exposure to maternal HAART starting in utero was associated with severe infant anemia. Confirmation of this finding and possible strategies to mitigate hematologic toxicity warrant further study.
ClinicalTrials.gov identifiers: NCT00197587 and NCT00270296.
Mother-to-Child Transmission; Anemia; Antiretroviral Therapy; Fetal Drug Exposure; Human Immunodeficiency Virus; Infant
Background Previously, HIV epidemic models have used a double Weibull curve to represent high initial and late mortality of HIV-infected children, without distinguishing timing of infection (peri- or post-natally). With more data on timing of infection, which may be associated with disease progression, a separate representation of children infected early and late was proposed.
Methods Paediatric survival post-HIV infection without anti-retroviral treatment was calculated using pooled data from 12 studies with known timing of HIV infection. Children were grouped into perinatally or post-natally infected. Net mortality was calculated using cause-deleted life tables to give survival as if HIV was the only competing cause of death. To extend the curve beyond the available data, children surviving beyond 2.5 years post infection were assumed to have the same survival as young adults. Double Weibull curves were fitted to both extended survival curves to represent survival of children infected perinatally or through breastfeeding.
Results Those children infected perinatally had a much higher risk of dying than those infected through breastfeeding, even allowing for background mortality. The final-fitted double Weibull curves gave 75% survival at 5 months after infection for perinatally infected, and 1.1 years for post-natally infected children. An estimated 25% of the early infected children would still be alive at 10.6 years compared with 16.9 years for those infected through breastfeeding.
Conclusions The increase in available data has enabled separation of child mortality patterns by timing of infection allowing improvement and more flexibility in modelling of paediatric HIV infection and survival.
HIV; survival; paediatric
Recently, the RV144 randomized, double-blind, efficacy trial in Thailand reported that a prime-boost human immunodeficiency virus (HIV) vaccine regimen conferred ∼30% protection against HIV acquisition. However, different analyses seemed to give conflicting results, and a heated debate ensued as scientists and the broader public struggled with their interpretation. The lack of accounting for statistical principles helped flame the debate, and we leverage these principles to provide a more scientific interpretation. We first address interpretation of frequentist results, including interpretation of P values, synthesis of results from multiple analyses (ie, intention-to-treat versus per-protocol/fully immunized), and accounting for external efficacy trials. Second, we address how Bayesian statistics, which provide clearly interpretable statements about probabilities that the vaccine efficacy takes certain values, provide more information for weighing the evidence about efficacy than do frequentist statistics alone. Third, we evaluate RV144 for completeness of end point ascertainment and integrity of blinding, necessary tasks for establishing robustly interpretable results.
Assumptions about survival of HIV-infected children in Africa without antiretroviral therapy need to be updated to inform ongoing UNAIDS modelling of paediatric HIV epidemics among children. Improved estimates of infant survival by timing of HIV-infection (perinatally or postnatally) are thus needed.
A pooled analysis was conducted of individual data of all available intervention cohorts and randomized trials on prevention of HIV mother-to-child transmission in Africa. Studies were right-censored at the time of infant antiretroviral initiation. Overall mortality rate per 1000 child-years of follow-up was calculated by selected maternal and infant characteristics. The Kaplan-Meier method was used to estimate survival curves by child's HIV infection status and timing of HIV infection. Individual data from 12 studies were pooled, with 12,112 children of HIV-infected women. Mortality rates per 1,000 child-years follow-up were 39.3 and 381.6 for HIV-uninfected and infected children respectively. One year after acquisition of HIV infection, an estimated 26% postnatally and 52% perinatally infected children would have died; and 4% uninfected children by age 1 year. Mortality was independently associated with maternal death (adjusted hazard ratio 2.2, 95%CI 1.6–3.0), maternal CD4<350 cells/ml (1.4, 1.1–1.7), postnatal (3.1, 2.1–4.1) or peri-partum HIV-infection (12.4, 10.1–15.3).
These results update previous work and inform future UNAIDS modelling by providing survival estimates for HIV-infected untreated African children by timing of infection. We highlight the urgent need for the prevention of peri-partum and postnatal transmission and timely assessment of HIV infection in infants to initiate antiretroviral care and support for HIV-infected children.
Increased stillbirth rates occur among HIV-infected women, but no studies have evaluated the pathological basis for this increase, or whether highly active antiretroviral therapy (HAART) influences the etiology of stillbirths. It is also unknown whether HIV infection of the fetus is associated with stillbirth.
HIV-infected women and a comparator group of HIV-uninfected women who delivered stillbirths were enrolled at the largest referral hospital in Botswana between January and November 2010. Obstetrical records, including antiretroviral use in pregnancy, were extracted at enrollment. Verbal autopsies; maternal HIV, CD4 and HIV RNA testing; stillbirth HIV PCR testing; and placental pathology (blinded to HIV and treatment status) were performed.
Ninety-nine stillbirths were evaluated, including 62 from HIV-infected women (34% on HAART from conception, 8% on HAART started in pregnancy, 23% on zidovudine started in pregnancy, and 35% on no antiretrovirals) and 37 from a comparator group of HIV-uninfected women. Only 2 (3.7%) of 53 tested stillbirths from HIV-infected women were HIV PCR positive, and both were born to women not receiving HAART. Placental insufficiency associated with hypertension accounted for most stillbirths. Placental findings consistent with chronic hypertension were common among HIV-infected women who received HAART and among HIV-uninfected women (65% vs. 54%, p = 0.37), but less common among HIV-infected women not receiving HAART (28%, p = 0.003 vs. women on HAART).
In utero HIV infection was rarely associated with stillbirths, and did not occur among women receiving HAART. Hypertension and placental insufficiency were associated with most stillbirths in this tertiary care setting.
Antiretroviral therapy that reduces viral replication could limit the transmission of human immunodeficiency virus type 1 (HIV-1) in serodiscordant couples.
In nine countries, we enrolled 1763 couples in which one partner was HIV-1–positive and the other was HIV-1–negative; 54% of the subjects were from Africa, and 50% of infected partners were men. HIV-1–infected subjects with CD4 counts between 350 and 550 cells per cubic millimeter were randomly assigned in a 1:1 ratio to receive antiretroviral therapy either immediately (early therapy) or after a decline in the CD4 count or the onset of HIV-1–related symptoms (delayed therapy). The primary prevention end point was linked HIV-1 transmission in HIV-1–negative partners. The primary clinical end point was the earliest occurrence of pulmonary tuberculosis, severe bacterial infection, a World Health Organization stage 4 event, or death.
As of February 21, 2011, a total of 39 HIV-1 transmissions were observed (incidence rate, 1.2 per 100 person-years; 95% confidence interval [CI], 0.9 to 1.7); of these, 28 were virologically linked to the infected partner (incidence rate, 0.9 per 100 person-years, 95% CI, 0.6 to 1.3). Of the 28 linked transmissions, only 1 occurred in the early-therapy group (hazard ratio, 0.04; 95% CI, 0.01 to 0.27; P<0.001). Subjects receiving early therapy had fewer treatment end points (hazard ratio, 0.59; 95% CI, 0.40 to 0.88; P = 0.01).
The early initiation of antiretroviral therapy reduced rates of sexual transmission of HIV-1 and clinical events, indicating both personal and public health benefits from such therapy.
The impact of in utero exposure to highly active antiretroviral therapy (HAART) on longitudinal growth of HIV-uninfected infants is unknown.
The Mashi and Mma Bana PMTCT intervention trials enrolled HIV-infected pregnant women at four sites in Botswana. Breastfed (BF), HIV-uninfected infants born ≥37 weeks were included in this analysis. Weight-for-age (WAZ), length-for-age (LAZ), and weight-for-length (WLZ) z-scores were calculated using WHO Child Growth Standards. Mean z-scores were compared between in utero ARV exposure groups using student’s t-test, response profiles analysis and general linear mixed effects modeling.
Growth of 619 HAART-exposed and 440 ZDV-exposed, HIV-uninfected infants was evaluated. Mean birth weights (BW) were 3.01 kg for HAART and 3.15 kg for ZDV-exposed infants (p<.001), with lower mean birth WAZ, LAZ, and WLZ among HAART-exposed infants (all p<.001). HAART-exposed infants had greater improvement in WAZ and WLZ from birth through 2 months (p=0.03, p <.001 respectively). WAZ did not differ between groups from 3 through 6 months (p=0.26). LAZ remained lower in HAART-exposed infants but the incidence of wasting or stunting did not differ between exposure groups.
Lower weights in HAART-exposed uninfected infants at birth were rapidly corrected during the first 6 months of life.
Prevention of mother-to-child transmission; HIV; growth
Standard values for birth weight by gestational age are not available for sub-Saharan Africa, but are needed to evaluate incidence and risk factors for intrauterine growth retardation in settings where HIV, antiretrovirals, and other in utero exposures may impact birth outcomes.
Birth weight data were collected from six hospitals in Botswana. Infants born to HIV-negative women between 26-44 weeks gestation were analyzed to construct birth weight for gestational age charts. These data were compared with published norms for black infants in the United States.
During a 29 month period from 2007-2010, birth records were reviewed in real-time from 6 hospitals and clinics in Botswana. Of these, 11,753 live infants born to HIV-negative women were included in the analysis. The median gestational age at birth was 39 weeks (1st quartile 38, 3rd quartile 40 weeks), and the median birth weight was 3100 grams (1st quartile 2800, 3rd quartile 3400 grams). We constructed estimated percentile curves for birth weight by gestational age which demonstrate increasing slope during the third trimester and leveling off beyond 40 weeks. Compared with black infants in the United States, Botswana-born infants had lower median birth weight for gestational age from weeks 37 through 42 (p < .02).
We present birth weight for gestational age norms for Botswana, which are lower at term than norms for black infants in the United States. These findings suggest the importance of regional birth weight norms to identify and define risk factors for higher risk births. These data serve as a reference for Botswana, may apply to southern Africa, and may help to identify infants at risk for perinatal complications and inform comparisons among infants exposed to HIV and antiretrovirals in utero.
Host genetic factors may be important determinants of HIV-1 sexual acquisition. We performed a genome-wide association study (GWAS) for host genetic variants modifying HIV-1 acquisition and viral control in the context of a cohort of African HIV-1 serodiscordant heterosexual couples. To minimize misclassification of HIV-1 risk, we quantified HIV-1 exposure, using data including plasma HIV-1 concentrations, gender, and condom use.
We matched couples without HIV-1 seroconversion to those with seroconversion by quantified HIV-1 exposure risk. Logistic regression of single nucleotide polymorphisms (SNPs) for 798 samples from 496 HIV-1 infected and 302 HIV-1 exposed, uninfected individuals was performed to identify factors associated with HIV-1 acquisition. In addition, a linear regression analysis was performed using SNP data from a subset (n = 403) of HIV-1 infected individuals to identify factors predicting plasma HIV-1 concentrations.
After correcting for multiple comparisons, no SNPs were significantly associated with HIV-1 infection status or plasma HIV-1 concentrations.
This GWAS controlling for HIV-1 exposure did not identify common host genotypes influencing HIV-1 acquisition. Alternative strategies, such as large-scale sequencing to identify low frequency variation, should be considered for identifying novel host genetic predictors of HIV-1 acquisition.
HLA class I-mediated selection of immune escape mutations in functionally important Gag epitopes may partly explain slower disease progression in HIV-1-infected individuals with protective HLA alleles. To investigate the impact of Gag function on disease progression, the replication capacities of viruses encoding Gag-protease from 60 individuals in early HIV-1 subtype C infection were assayed in an HIV-1-inducible green fluorescent protein reporter cell line and were correlated with subsequent disease progression. Replication capacities did not correlate with viral load set points (P = 0.37) but were significantly lower in individuals with below-median viral load set points (P = 0.03), and there was a trend of correlation between lower replication capacities and lower rates of CD4 decline (P = 0.09). Overall, the proportion of host HLA-specific Gag polymorphisms in or adjacent to epitopes was negatively associated with replication capacities (P = 0.04), but host HLA-B-specific polymorphisms were associated with higher viral load set points (P = 0.01). Further, polymorphisms associated with host-specific protective HLA alleles were linked with higher viral load set points (P = 0.03). These data suggest that transmission or early HLA-driven selection of Gag polymorphisms results in reduced early cytotoxic T-lymphocyte (CTL) responses and higher viral load set points. In support of the former, 46% of individuals with nonprotective alleles harbored a Gag polymorphism exclusively associated with a protective HLA allele, indicating a high rate of their transmission in sub-Saharan Africa. Overall, HIV disease progression is likely to be affected by the ability to mount effective Gag CTL responses as well as the replication capacity of the transmitted virus.
Single-dose nevirapine (sdNVP) is widely used to prevent mother-to-child transmission (PMTCT) of HIV-1. This may result in NVP resistance in both mother and infant. The significance of low levels of NVP resistance mutations in infants treated with NVP-containing antiretroviral treatment (ART) is unknown.
To determine the presence of pre-treatment NVP resistance in HIV-infected infants with and without prior NVP exposure.
33 HIV-1-infected infants in a PMTCT trial received NVP-containing ART (26 infants with prior NVP exposure). Plasma and buffy coat samples obtained prior to ART initiation were evaluated for drug resistance by bulk sequencing and allele-specific PCR (ASPCR).
ViroSeq™ identified NVP resistance in 3 of 33 infants; all failed first-line therapy. Pre-ART plasma NVP resistance by ASPCR was detected in 9 of 16 children experiencing virologic failure compared to 4 of 17 children without virologic failure (risk ratio 2.4, CI 0.94-7.8, p=0.08). Proviral resistance was not associated with virologic failure (risk ratio 1.2, CI 0.8-2.0, p= 0.40). In the nevirapine-exposed infants, those who started ART before 7 months had higher risk of virologic failure (RR 2.3; CI 0.96-9.2; p=0.11).
Low level drug resistance detected in plasma after NVP exposure prior to ART initiation may be associated with virologic failure on ART, while resistance in the DNA reservoir was not predictive of treatment outcome.
HIV; minor variant; drug resistance; nevirapine; PMTCT
National initiatives offering NNRTI-based combination antiretroviral therapy (cART) have expanded in sub-Saharan Africa (SSA). The Tshepo study is the first clinical trial evaluating the long-term efficacy and tolerability of EFV- vs. NVP-based cART among adults in Botswana.
Three year randomized study (n = 650) using a 3×2×2 factorial design comparing efficacy and tolerability among: A: ZDV/3TC vs. ZDV/ddI vs. d4T/3TC; B: EFV vs. NVP, and C: Com-DOT vs. standard adherence strategies. This manuscript focuses on comparison B.
There was no significant difference by assigned NNRTI in time to virologic failure with resistance (log-rank p = 0.14), NVP vs. EFV risk ratio (RR) = 1.54 [0.86-2.70]. Rates of virologic failure with resistance were 9.6% NVP-treated [6.8-13.5] vs. 6.6% EFV-treated [4.2-10.0] at 3 years. Women receiving NVP-based cART trended towards higher virological failure rates when compared to EFV-treated women, Holm-corrected log-rank p = 0.072, NVP vs. EFV RR = 2.22 [0.94-5.00]. 139 patients had 176 treatment modifying toxicities, with shorter time to event in NVP-treated vs. EFV-treated, RR = 1.85 [1.20-2.86], log-rank p = 0.0002.
Tshepo-treated patients had excellent overall immunologic and virologic outcomes, and no significant differences were observed by randomized NNRTI comparison. NVP-treated women trended towards higher virologic failure with resistance compared to EFV-treated women. NVP-treated adults had higher treatment modifying toxicity rates when compared to those receiving EFV. NVP-based cART can continue to be offered to women in SSA if routine safety monitoring chemistries are done and the potential risk of EFV-related teratogenicity is considered.
HIV/AIDS; HAART; non-nucleoside reverse transcriptase inhibitors (NNRTI’s); nevirapine versus efavirenz; sub-Saharan Africa; randomized clinical trial
Numerous national antiretroviral (ARV) treatment initiatives offering protease-inhibitor (PI)-sparing combination antiretroviral therapy (cART) have recently commenced in southern Africa, the first of which began in Botswana in January 2002. Evaluation of the efficacy and tolerability of various PI-sparing cART regimens requires intensive study in the region, as does investigation of the development of drug resistance and the optimal means of sustaining adherence. The Tshepo Study is the first large-scale randomized clinical trial which addresses these important issues among HIV-1 subtype C infected, ARV-treatment naïve adults in southern Africa.
The Tshepo Study is a completed open-labeled randomized study that enrolled 650 ARV-naïve adults between December 2002 and December 2004. The study is a 3 × 2 × 2 factorial design comparing the efficacy and tolerability among factors: (i) three combinations of nucleoside reverse transcriptase inhibitors (NRTIs): zidovudine (ZDV) + lamivudine (3TC); ZDV + didanosine (ddI); and stavudine (d4T) + 3TC; (ii) two different Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs): nevirapine (NVP) and efavirenz (EFV); and (iii) two different adherence strategies: the current national “Standard of Care (SOC)” versus an “intensified adherence strategy”, incorporating “community-based Directly Observed Therapy (Com-DOT)”. Study patients were stratified into two balanced CD4+ T cell count groups: less than 201 cells/mm3 versus 201-350 cells/mm3 with viral load greater than 55,000 copies/mL. Following DSMB recommendations in April 2006, ZDV/ddI-containing arms were discontinued due to inferiority in primary endpoint, namely, virologic failure with resistance. We report both overall data and pooled data from patients receiving ZDV/ddI- versus ZDV/3TC- and d4T/3TC-containing cART through 1 April 2006.
Four hundred fifty-one (69.4%) females and 199 males with a median age of 33.3 years were enrolled into the study. The median follow-up as of 1 April 2006 was 104 weeks, and loss to follow-up rate at two years was 4.1%. The median baseline CD4+ T cell count was 199 cells/mm3 [IQR 136-252] and the median plasma HIV-1 RNA level was 193,500 copies/mL [IQR 69-250, 472-500]. The proportion of participants with virologic failure and genotypic resistance mutations was 11% in those receiving ZDV/ddI-based cART versus 2% in those receiving either ZDV/3TC- or d4T/3TC-based cART (p=0.002). The median CD4+ T cell count increase at one year was 137cells/mm3 [IQR 74-223] and 199 cells/mm3 [IQR 112-322] at two years with significantly lower gain in the ZDV/ddI arm. At one and two years, respectively, 92.0% and 88.8% of patients had an undetectable plasma HIV-1 RNA level (≤400 copies/mL). Kaplan-Meier survival estimates at one and two years were 96.6% and 95.4%. One hundred twenty (18.2%) patients had treatment modifying toxicities, of which the most common were lipodystrophy, anemia, neutropenia, and Stevens-Johnson syndrome. There was a trend towards difference in time to treatment modifying toxicity by pooled dual NRTI combination, and no difference in death rates.
The preliminary study results show overall excellent efficacy and tolerability of NNRTI-based cART among HIV-1 subtype C infected adults. ZDV/ddI-containing cART, however, is inferior to the dual NRTIs d4T/3TC or ZDV/3TC when used with an NNRTI for first-line cART.
HIV/AIDS; cART; Africa; Randomized clinical trial
Numerous national public initiatives offering first-line combination antiretroviral therapy (cART) for HIV infection have commenced in sub-Saharan Africa since 2002. Presently, 2.1 million of an estimated seven million Africans in need of cART are receiving treatment. Analyses from the region report favorable clinical/treatment outcomes and impressive declines in AIDS-related mortality among HIV-1-infected adults and children receiving cART. While immunologic recovery, virologic suppression and cART adherence rates are on par with resource-rich settings, loss to follow-up and high mortality rates, especially within the first 6 months of treatment, remain a significant problem. Over the next decade, cART coverage rates are expected to improve across the region, with attendant increases in healthcare utilization for HIV- and non-HIV-related complications and the need for expanded laboratory and clinical services. Planned and in-progress trials will evaluate the use of cART to prevent primary HIV-1 infection with so-called ‘test and treat’ expansions of coverage and treatment. Education and training programs as well as patient-retention strategies will need to be strengthened as national cART programs are expanded and more people require lifelong monitoring and care.
adherence; cART; combination antiretroviral therapy; efficacy; HIV/AIDS; mortality/survival; sub-Saharan Africa; tolerability/toxicity
Antiretroviral treatment (ART) initiatives have now been established in many sub-Saharan African countries showing early benefits. To date, few results are available concerning long-term clinical outcomes in these treatment programs.
Response to ART is described in the first HIV–1C infected adults enrolled in the Botswana ART program in 2002. Data analysis was conducted on available longitudinal data up to April 1st, 2007.
633 severely immunodeficient patients with a median CD4+ cell count of 67 cells/mm3 were initiated on NNRTI-based combination ART and followed for a median of 41.9 months. The median CD4+ increases were 169 cells/mm3, 302 cells/mm3, and 337 cells/mm3 at 1, 3, and 5 years, respectively. The percentages of patients with a viral load of less than 400 copies/mL at 1, 3, and 5 years were 91.3%, 90.1%, and 98.3%, respectively. 75% of patients did not miss a single, or missed only one, monthly ART pick-up per year with a mean pick-up rate of 92.5%. The Kaplan-Meier survival estimates (95% CI) at 1, 3, and 5 years were 82.7% (81.2%, 84.3%), 79.3% (77.6%, 81.0%), and 79.0% (77.3%, 80.7%), respectively. At six months, the risk of treatment modification for anemia was 6.94% (5.9%, 8.0%) for cutaneous hypersensitivity reactions, 1.3% (0.8%, 1.7%), and 1.1% (0.7%, 1.6%) for hepatotoxicity.
This initial group of adults on ART in Botswana had excellent sustained immunologic, virologic, and clinical outcomes for up to five years of follow-up with low mortality among those surviving into the second year of antiretroviral treatment.
HIV/AIDS; Africa; antiretroviral therapy; Botswana; public sector
The diversity of HIV-1 and its propensity to generate escape mutants present fundamental challenges to control efforts, including HIV vaccine design. Intra-host diversification of HIV is determined by immune responses elicited by an HIV-infected individual over the course of the infection. Complex and dynamic patterns of transmission of HIV lead to an even more complex population viral diversity over time, thus presenting enormous challenges to vaccine development. To address inter-patient viral evolution over time, a set of 653 unique HIV-1 subtype C gag sequences were retrieved from the LANL HIV Database, grouped by sampling year as <2000, 2000, 2001–2002, 2003, and 2004–2006, and analyzed for the site-specific frequency of translated amino acid residues. Phylogenetic analysis revealed that a total of 289 out of 653 (44.3%) analyzed sequences were found within 16 clusters defined by aLRT of more than 0.90. Median (IQR) inter-sample diversity of analyzed gag sequences was 8.7% (7.7%; 9.8%). Despite the heterogeneous origins of analyzed sequences, the gamut and frequency of amino acid residues in wild-type Gag were remarkably stable over the last decade of the HIV-1 subtype C epidemic. The vast majority of amino acid residues demonstrated minor frequency fluctuation over time, consistent with the conservative nature of the HIV-1 Gag protein. Only 4.0% (20 out of 500; HXB2 numbering) amino acid residues across Gag displayed both statistically significant (p<0.05 by both a trend test and heterogeneity test) changes in amino acid frequency over time as well as a range of at least 10% in the frequency of the major amino acid. A total of 59.2% of amino acid residues with changing frequency of 10%+ were found within previously identified CTL epitopes. The time of the most recent common ancestor of the HIV-1 subtype C was dated to around 1950 (95% HPD from 1928 to 1962). This study provides evidence for the overall stability of HIV-1 subtype C Gag among viruses circulating in the epidemic over the last decade. However selected sites across HIV-1C Gag with changing amino acid frequency are likely to be under selection pressure at the population level.
HIV-1 subtype C; consensus sequence; amino acid frequency; Gag; gag phylogeny; CTL epitopes; time of MRCA