Adherence to PI-based 2nd-line regimens in Cambodia is not simply a question of individual behaviour: the ANRS 12276 2PICAM study.

OBJECTIVES: To investigate whether adherence to antiretroviral treatment (ART) can be explained not only by individual factors but also by health care facilities' characteristics, among a sample of people living with HIV (PLWH) treated with PI-based regimens in Cambodia. METHODS: The ANRS 12276 2PICAM cross-sectional survey was conducted between February 2013 and April 2014 among PLWH followed up in 13 health care facilities. The 1316 patients in this analysis corresponded to 90% of the total number of adult patients treated with 2nd-line PI-based regimens in Cambodia in the study period. A variable indicating whether patients were non-adherent (=1) or completely adherent (=0) was constructed. Health care facilities and individual characteristics were included in a two-level logistic model to investigate their influence on patients' adherence to ART. RESULTS: A total of 17% of participants did not adhere to ART. Patients in health care facilities outside the capital Phnom Penh were six times more likely to be non-adherent than those treated in health care facilities in the capital (OR: 6.15, 95% CI [1.47, 25.79]). Providing psychosocial care (provided by psychologist counsellors and/or full-time coaches) was found to be a structural facilitator of adherence, as the probability of non-adherence fell by 38.5% per each additional psychological worker present in health care facilities (OR: 0.62, 95% CI [0.43, 0.89]). Financial constraints were the main individual factor preventing adherence. CONCLUSIONS: Our results suggest that inefficiencies in health care delivery are detrimental to PLWH health and to the exceptional progress currently being made by Cambodia in response to HIV. Policy makers should focus on increasing the number of psychosocial workers, especially in areas outside the capital.

Zoonotic Transmission of Two New Strains of Human T-lymphotropic Virus Type 4 in Hunters Bitten by a Gorilla in Central Africa.

Molecular screening of 300 at-risk people from Central Africa identified 2 human T-lymphotropic virus (HTLV)-4-infected individuals. A zoonotic origin of infection was suggested, as both individuals reported being severely bitten by a gorilla during hunting activities. One strain was highly divergent and was designated as the HTLV-4 subtype-b prototype.

Different selective pressures shape the evolution of Toll-like receptors in human and African great ape populations.

The study of the genetic and selective landscape of immunity genes across primates can provide insight into the existing differences in susceptibility to infection observed between human and non-human primates. Here, we explored how selection has driven the evolution of a key family of innate immunity receptors, the Toll-like receptors (TLRs), in African great ape species. We sequenced the 10 TLRs in various populations of chimpanzees and gorillas, and analysed these data jointly with a human data set. We found that purifying selection has been more pervasive in great apes than in humans. Furthermore, in chimpanzees and gorillas, purifying selection has targeted TLRs irrespectively of whether they are endosomal or cell surface, in contrast to humans where strong selective constraints are restricted to endosomal TLRs. These observations suggest important differences in the relative importance of TLR-mediated pathogen sensing, such as that of recognition of flagellated bacteria by TLR5, between humans and great apes. Lastly, we used a population genetics-phylogenetics method that jointly analyses polymorphism and divergence data to detect fine-scale variation in selection pressures at specific codons within TLR genes. We identified different codons at different TLRs as being under positive selection in each species, highlighting that functional variation at these genes has conferred a selective advantage in immunity to infection to specific primate species. Overall, this study showed that the degree of selection driving the evolution of TLRs has largely differed between human and non-human primates, increasing our knowledge on their respective biological contribution to host defence in the natural setting.

African great apes are naturally infected with roseoloviruses closely related to human herpesvirus 7.

UNLABELLED: Primates are naturally infected with herpesviruses. During the last 15 years, the search for homologues of human herpesviruses in nonhuman primates allowed the identification of numerous viruses belonging to the different herpesvirus subfamilies and genera. No simian homologue of human herpesvirus 7 (HHV7) has been reported to date. To investigate the putative existence of HHV7-like viruses in African great apes, we applied the consensus-degenerate hybrid oligonucleotide primers (CODEHOP) program-mediated PCR strategy to blood DNA samples from the four common chimpanzee subspecies (Pan troglodytes verus, P. t. ellioti, P. t. troglodytes, and P. t. schweinfurthii), pygmy chimpanzees (Pan paniscus), as well as lowland gorillas (Gorilla gorilla gorilla). This study led to the discovery of a novel roseolovirus close to HHV7 in each of these nonhuman primate species and subspecies. Generation of the partial glycoprotein B (1,111-bp) and full-length DNA polymerase (3,036/3,042-bp) gene sequences allowed the deciphering of their evolutionary relationships. Phylogenetic analyses revealed that HHV7 and its African great ape homologues formed well-supported monophyletic lineages whose topological resemblance to the host phylogeny is suggestive of virus-host codivergence. Notably, the evolutionary branching points that separate HHV7 from African great ape herpesvirus 7 are remarkably congruent with the dates of divergence of their hosts. Our study shows that African great apes are hosts of human herpesvirus homologues, including HHV7 homologues, and that the latter, like other DNA viruses that establish persistent infections, have cospeciated with their hosts. IMPORTANCE: Human herpesviruses are known to possess simian homologues. However, surprisingly, none has been identified to date for human herpesvirus 7 (HHV7). This study is the first to describe simian homologues of HHV7. The extensive search performed on almost all African great ape species and subspecies, i.e., common chimpanzees of the four subspecies, bonobos, and lowland gorillas, has allowed characterization of a specific virus in each. Genetic characterization of the partial glycoprotein B and full-length DNA polymerase gene sequences, followed by their phylogenetic analysis and estimation of divergence times, has shed light on the evolutionary relationships of these viruses. In this respect, we conclusively demonstrate the cospeciation between these new viruses and their hosts and report cases of cross-species transmission between two common chimpanzee subspecies in both directions.

Genomic tools for evolution and conservation in the chimpanzee: Pan troglodytes ellioti is a genetically distinct population.

In spite of its evolutionary significance and conservation importance, the population structure of the common chimpanzee, Pan troglodytes, is still poorly understood. An issue of particular controversy is whether the proposed fourth subspecies of chimpanzee, Pan troglodytes ellioti, from parts of Nigeria and Cameroon, is genetically distinct. Although modern high-throughput SNP genotyping has had a major impact on our understanding of human population structure and demographic history, its application to ecological, demographic, or conservation questions in non-human species has been extremely limited. Here we apply these tools to chimpanzee population structure, using ∼700 autosomal SNPs derived from chimpanzee genomic data and a further ∼100 SNPs from targeted re-sequencing. We demonstrate conclusively the existence of P. t. ellioti as a genetically distinct subgroup. We show that there is clear differentiation between the verus, troglodytes, and ellioti populations at the SNP and haplotype level, on a scale that is greater than that separating continental human populations. Further, we show that only a small set of SNPs (10-20) is needed to successfully assign individuals to these populations. Tellingly, use of only mitochondrial DNA variation to classify individuals is erroneous in 4 of 54 cases, reinforcing the dangers of basing demographic inference on a single locus and implying that the demographic history of the species is more complicated than that suggested analyses based solely on mtDNA. In this study we demonstrate the feasibility of developing economical and robust tests of individual chimpanzee origin as well as in-depth studies of population structure. These findings have important implications for conservation strategies and our understanding of the evolution of chimpanzees. They also act as a proof-of-principle for the use of cheap high-throughput genomic methods for ecological questions.

Earlier versus later start of antiretroviral therapy in HIV-infected adults with tuberculosis.

BACKGROUND: Tuberculosis remains an important cause of death among patients infected with the human immunodeficiency virus (HIV). Robust data are lacking with regard to the timing for the initiation of antiretroviral therapy (ART) in relation to the start of antituberculosis therapy. METHODS: We tested the hypothesis that the timing of ART initiation would significantly affect mortality among adults not previously exposed to antiretroviral drugs who had newly diagnosed tuberculosis and CD4+ T-cell counts of 200 per cubic millimeter or lower. After beginning the standard, 6-month treatment for tuberculosis, patients were randomly assigned to either earlier treatment (2 weeks after beginning tuberculosis treatment) or later treatment (8 weeks after) with stavudine, lamivudine, and efavirenz. The primary end point was survival. RESULTS: A total of 661 patients were enrolled and were followed for a median of 25 months. The median CD4+ T-cell count was 25 per cubic millimeter, and the median viral load was 5.64 log(10) copies per milliliter. The risk of death was significantly reduced in the group that received ART earlier, with 59 deaths among 332 patients (18%), as compared with 90 deaths among 329 patients (27%) in the later-ART group (hazard ratio, 0.62; 95% confidence interval [CI]; 0.44 to 0.86; P=0.006). The risk of tuberculosis-associated immune reconstitution inflammatory syndrome was significantly increased in the earlier-ART group (hazard ratio, 2.51; 95% CI, 1.78 to 3.59; P<0.001). Irrespective of the study group, the median gain in the CD4+ T-cell count was 114 per cubic millimeter, and the viral load was undetectable at week 50 in 96.5% of the patients. CONCLUSIONS: Initiating ART 2 weeks after the start of tuberculosis treatment significantly improved survival among HIV-infected adults with CD4+ T-cell counts of 200 per cubic millimeter or lower. (Funded by the French National Agency for Research on AIDS and Viral Hepatitis and the National Institutes of Health; CAMELIA ClinicalTrials.gov number, NCT01300481.).

Natural killer cell degranulation capacity predicts early onset of the immune reconstitution inflammatory syndrome (IRIS) in HIV-infected patients with tuberculosis.

Immune reconstitution inflammatory syndrome (IRIS) is a common and potentially serious complication occurring in HIV-infected patients being treated for tuberculosis (TB) using combined antiretroviral treatment. A role of adaptive immunity has been suggested in the onset of IRIS, whereas the role of natural killer (NK) cells has not yet been explored. The present study sought to examine the involvement of NK cells in the onset of IRIS in HIV-infected patients with TB and to identify predictive markers of IRIS. A total of 128 HIV-infected patients with TB from the Cambodian Early versus Late Introduction of Antiretroviral Drugs (CAMELIA) trial were enrolled in Cambodia. Thirty-seven of the 128 patients developed IRIS. At inclusion, patients had low CD4 cell counts (27 cells/mm(3)) and high plasma viral load (5.76 and 5.50 log/mL in IRIS and non-IRIS patients, respectively). At baseline, NK-cell degranulation capacity was significantly higher in IRIS patients than in non-IRIS patients (9.6% vs 6.38%, P < .005). At IRIS onset, degranulation capacity did not differ between patients, whereas activating receptor expression was lower in IRIS patients. Patients with degranulation levels > 10.84% had a higher risk of IRIS (P = .002 by log-rank test). Degranulation level at baseline was the most important IRIS predictor (hazard ratio = 4.41; 95% confidence interval, 1.60-12.16). We conclude that NK-degranulation levels identify higher IRIS risk in HIV-infected patients with TB.

African apes as reservoirs of Plasmodium falciparum and the origin and diversification of the Laverania subgenus.

We investigated two mitochondrial genes (cytb and cox1), one plastid gene (tufA), and one nuclear gene (ldh) in blood samples from 12 chimpanzees and two gorillas from Cameroon and one lemur from Madagascar. One gorilla sample is related to Plasmodium falciparum, thus confirming the recently reported presence in gorillas of this parasite. The second gorilla sample is more similar to the recently defined Plasmodium gaboni than to the P. falciparum-Plasmodium reichenowi clade, but distinct from both. Two chimpanzee samples are P. falciparum. A third sample is P. reichenowi and two others are P. gaboni. The other chimpanzee samples are different from those in the ape clade: two are Plasmodium ovale, and one is Plasmodium malariae. That is, we have found three human Plasmodium parasites in chimpanzees. Four chimpanzee samples were mixed: one species was P. reichenowi; the other species was P. gaboni in three samples and P. ovale in the fourth sample. The lemur sample, provisionally named Plasmodium malagasi, is a sister lineage to the large cluster of primate parasites that does not include P. falciparum or ape parasites, suggesting that the falciparum + ape parasite cluster (Laverania clade) may have evolved from a parasite present in hosts not ancestral to the primates. If malignant malaria were eradicated from human populations, chimpanzees, in addition to gorillas, might serve as a reservoir for P. falciparum.

[Tuberculosis and HIV co-infection: clinical trial under the coordination of the Institut Pasteur in Cambodia]. / Co-infection tuberculose et VIH: coordination d'un essai clinique randomisé par l'Institut Pasteur du Cambodge.

Tuberculosis is a major cause of death among adults infected by HIV. The CAMELIA (ANRS 1295/CIPRA KH001) randomized clinical trial aimed to determine the optimal timing of ARV initiation after tuberculosis treatment onset to reduce mortality. Here, we describe the trial implementation in five hospitals in Cambodia under the coordination of the Institut Pasteur in Cambodia, its conduct, the challenges and public health benefits in Cambodia and beyond.

Natural Killer Repertoire Restoration in TB/HIV Co-Infected Individuals Experienced an Immune Reconstitution Syndrome (CAMELIA Trial, ANRS 12153).

IRIS is a common complication in HIV-infected patients treated for tuberculosis (TB) and cART. Our aim was to evaluate NK cell reconstitution in HIV-infected patients with TB-IRIS compared to those without IRIS. 147 HIV-infected patients with TB from the CAMELIA trial were enrolled. HIV+TB+ patients were followed for 32 weeks. The NK cell repertoire was assessed in whole blood at different time points. As CAMELIA has two arms (early and late cART initiation), we analysed them separately. At enrolment, individuals had low CD4 cell counts (27 cells/mm3) and high plasma viral loads (5.76 and 5.50 log/mL for IRIS and non-IRIS individuals, respectively). Thirty-seven people developed IRIS (in the early and late arms). In the early and late arms, we observed similar proportions of total NK and NK cell subsets in TB-IRIS and non-IRIS individuals during follow-up, except for the CD56dimCD16pos (both arms) and CD56dimCD16neg (late arm only) subsets, which were higher in TB-IRIS and non-IRIS individuals, respectively, after cART. Regarding the repertoire and markers of NK cells, significant differences (lower expression of NKp30, NKG2A (CD159a), NKG2D (CD314) were observed in TB-IRIS compared to non-IRIS individuals after the start of cART. In the late arm, some changes (increased expression of CD69, NKG2C, CD158i) were observed in TB-IRIS compared to non-IRIS individuals, but only before cART initiation (during TB treatment). KIR expression by NK cells (CD158a and CD158i) was similar in both groups. CD69 expression by NK cells decreased in all groups. Expression of the NCR repertoire (NKp30, NKp44, NKp46) has similar kinetics in TB-IRIS subjects compared to non-IRIS subjects regardless of the arm analysed. NK cell reconstitution appeared to be better in TB-IRIS subjects. Although NK cell reconstitution is impaired in HIV infection after cART, as previously reported, it does not appear to be affected by the development of IRIS in HIV and TB-infected individuals.

High Seroprevalence of IgG Antibodies to Multiple Arboviruses in People Living with HIV (PLWHIV) in Madagascar.

To estimate the prevalence of IgG antibodies against six arboviruses in people living with HIV-1 (PLWHIV) in Madagascar, we tested samples collected between January 2018 and June 2021. We used a Luminex-based serological assay to detect IgG antibodies against antigens from Dengue virus serotypes 1-4 (DENV1-4), Zika virus (ZIKV), West Nile virus (WNV), Usutu virus (USUV), Chikungunya virus (CHIKV), and O'nyong nyong virus (ONNV). Of the 1036 samples tested, IgG antibody prevalence was highest for ONNV (28.4%), CHIKV (26.7%), WNV-NS1 (27.1%), DENV1 (12.4%), USUV (9.9%), and DENV3 (8.9%). ZIKV (4.9%), DENV2 (4.6%), WNV-D3 (5.1%), and DENV4 (1.4%) were lower. These rates varied by province of origin, with the highest rates observed in Toamasina, on the eastern coast (50.5% and 56.8%, for CHIKV and ONNV, respectively). The seroprevalence increased with age for DENV1 and 3 (p = 0.006 and 0.038, respectively) and WNV DIII (p = 0.041). The prevalence of IgG antibodies against any given arborvirus varied over the year and significantly correlated with rainfalls in the different areas (r = 0.61, p = 0.036). Finally, we found a significant correlation between the seroprevalence of antibodies against CHIKV and ONNV and the HIV-1 RNA plasma viral load. Thus, PLWHIV in Madagascar are highly exposed to various arboviruses. Further studies are needed to explain some of our findings.

Prediction of treatment failure using 2010 World Health Organization Guidelines is associated with high misclassification rates and drug resistance among HIV-infected Cambodian children.

BACKGROUND: Antiretroviral therapy (ART) in resource-limited settings (RLSs) is monitored clinically and immunologically, according to World Health Organization (WHO) or national guidelines. Revised WHO pediatric guidelines were published in 2010, but their ability to accurately identify virological failure is unclear. METHODS: We evaluated performance of WHO 2010 guidelines and compared them with WHO 2006 and Cambodia 2011 guidelines among children on ≥6 months of first-line ART at Angkor Hospital for Children between January 2005 and September 2010. We determined sensitivity, specificity, positive and negative predictive values, and accuracy using bootstrap resampling to account for multiple tests per child. Human immunodeficiency virus (HIV) resistance was compared between those correctly and incorrectly identified by each guideline. RESULTS: Among 457 children with 1079 viral loads (VLs), 20% had >400 copies/mL. For children with WHO stage 1/2 HIV, misclassification as failure (met CD4 failure criteria, but VL undetectable) was 64% for WHO 2006 guidelines, 33% for WHO 2010 guidelines, and 81% for Cambodia 2011 guidelines; misclassification as success (did not meet CD4 failure, but VL detectable) was 11%, 12%, and 12%, respectively. For children with WHO stage 3/4 HIV, misclassification as failure was 35% for WHO 2006 guidelines, 40% for WHO 2010 guidelines, and 43% for Cambodia 2011 guidelines; misclassification as success was 13%, 24%, and 21%, respectively. Compared with WHO 2006 guidelines, WHO 2010 guidelines significantly increased the risk of misclassification as success in stage 3/4 HIV (P < .05). The WHO 2010 guidelines failed to identify 98% of children with extensive reverse-transcriptase resistance. CONCLUSIONS: In our cohort, lack of virological monitoring would result in unacceptable treatment failure misclassification, leading to premature ART switch and resistance accumulation. Affordable virological monitoring suitable for use in RLSs is desperately needed.

Characterization of a new simian immunodeficiency virus strain in a naturally infected Pan troglodytes troglodytes chimpanzee with AIDS related symptoms.

BACKGROUND: Data on the evolution of natural SIV infection in chimpanzees (SIVcpz) and on the impact of SIV on local ape populations are only available for Eastern African chimpanzee subspecies (Pan troglodytes schweinfurthii), and no data exist for Central chimpanzees (Pan troglodytes troglodytes), the natural reservoir of the ancestors of HIV-1 in humans. Here, we report a case of naturally-acquired SIVcpz infection in a P.t.troglodytes chimpanzee with clinical and biological data and analysis of viral evolution over the course of infection. RESULTS: A male chimpanzee (Cam155), 1.5 years, was seized in southern Cameroon in November 2003 and screened SIV positive during quarantine. Clinical follow-up and biological analyses have been performed for 7 years and showed a significant decline of CD4 counts (1,380 cells/mm³ in 2004 vs 287 in 2009), a severe thrombocytopenia (130,000 cells/mm³ in 2004 vs 5,000 cells/mm³ in 2009), a weight loss of 21.8% from August 2009 to January 2010 (16 to 12.5 kg) and frequent periods of infections with diverse pathogens.DNA from PBMC, leftover from clinical follow-up samples collected in 2004 and 2009, was used to amplify overlapping fragments and sequence two full-length SIVcpzPtt-Cam155 genomes. SIVcpzPtt-Cam155 was phylogenetically related to other SIVcpzPtt from Cameroon (SIVcpzPtt-Cam13) and Gabon (SIVcpzPtt-Gab1). Ten molecular clones 5 years apart, spanning the V1V4 gp120 env region (1,100 bp), were obtained. Analyses of the env region showed positive selection (dN-dS >0), intra-host length variation and extensive amino acid diversity between clones, greater in 2009. Over 5 years, N-glycosylation site frequency significantly increased (p < 0.0001). CONCLUSIONS: Here, we describe for the first time the clinical history and viral evolution of a naturally SIV infected P.t.troglodytes chimpanzee. The findings show an increasing viral diversity over time and suggest clinical progression to an AIDS-like disease, showing that SIVcpz can be pathogenic in its host, as previously described in P.t.schweinfurthii. Although studying the impact of SIV infection in wild apes is difficult, efforts should be made to better characterize the pathogenicity of the ancestors of HIV-1 in their natural host and to find out whether SIV infection also plays a role in ape population decline.

Population pharmacokinetics of nevirapine in HIV-1-infected pregnant women and their neonates.

The aim of the present study was to describe the nevirapine (NVP) pharmacokinetics (PK) in pregnant women and their neonates and to evaluate the transplacental drug transfer and administration scheme for the prevention of mother-to-child transmission. Thirty-eight HIV-1-infected pregnant women were administered one tablet of NVP (200 mg) and two tablets of tenofovir-emtricitabine (Truvada) at the initiation of labor. Children were given NVP syrup (2 mg/kg of body weight) as a single dose (sdNVP) on the first day of life. By pair, NVP concentrations were measured in 11 maternal, 1 cord blood, and 2 neonatal plasma samples and analyzed by a population approach. A one-compartment model was used for mothers and neonates; the absorption rate constants for mothers and neonates were 0.95 h(-1) (intersubject variability, 111%) and 0.39 h(-1), respectively; the apparent elimination clearances were 1.42 liter·h(-1) (intersubject variability, 22%) and 0.035 liter·h(-1), respectively; and apparent volumes of distribution were 87.3 liters (intersubject variability, 25%) and 5.65 liters, respectively. An effect compartment was linked to maternal circulation by mother-to-cord and cord-to-mother rate constants of 1.10 h(-1) and 1.43 h(-1), respectively. Placental transfer, expressed as the fetal-to-maternal area under the curve ratio, was 75%. Neonates had a very long half-lives (110 h) compared to adults. In the 38 mothers, the simulated median individual predicted time during which the NVP concentration remained above the half-maximal inhibitory concentration (IC(50)) was 13.2 days (range, 12 to 19.2 days). Thus, the administration of tenofovir-emtricitabine for at least 3 weeks after delivery should be considered to prevent the emergence of resistant viruses. The neonate must receive sdNVP immediately after birth when the infant is born less than 30 min after maternal drug intake to keep NVP concentrations above the IC(50).

Very high concentrations of active intracellular phosphorylated emtricitabine in neonates (ANRS 12109 trial, step 2).

Our objective was to investigate neonatal emtricitabine (FTC) plasma and intracellular pharmacokinetics. The study was designed as a phase I/II prospective trial in two sequential steps evaluating the combination of tenofovir disoproxil fumarate (TDF) and FTC for the prevention of mother-to-child-transmission (PMTCT) of HIV. HIV-1-infected pregnant women received two tablets of TDF (300 mg) and FTC (200 mg) at onset of labor and then one tablet daily for 7 days postpartum. Based on the data obtained in the first part of the Tenofovir/Emtricitabine in Africa and Asia (TEmAA) Study, single doses of 2 mg/kg of FTC and 13 mg/kg of TDF were given to the neonates within 12 h after birth. A total of 540 FTC plasma concentrations and 44 active intracellular phosphorylated metabolite FTC-TP concentrations were taken from the 36 enrolled women and their neonates. Concentrations were measured by the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and analyzed by a population approach. The proposed dose obtained by simulations based on plasma drug concentrations was confirmed. However, median FTC-TP exposures were, respectively, 5.9 and 6.8 times higher in the fetus and the neonate than in the adult. High FTC-TP concentrations were observed in the four children who had serious adverse events (SAEs), but the link between FTC-TP concentrations and SAEs in children was not formally identified. The exposure to the active form of FTC was high in neonates despite plasma drug concentrations equivalent to those in adults. Our results are similar to those obtained with zidovudine or lamivudine.

Immunovirological outcomes and resistance patterns at 4 years of antiretroviral therapy use in HIV-infected patients in Cambodia.

OBJECTIVES: To report immunovirological outcomes and resistance patterns in adults treated with triple combination antiretroviral therapy (cART) for 4 years in an HIV programme of Phnom Penh, Cambodia. METHODS: It is a longitudinal study and cross-sectional evaluation of adults receiving cART for 4 years. CD4 cell counts and HIV-1 RNA were quantified, and resistance patterns were determined. Drug-related toxicity was assessed by clinicians and through laboratory testing. RESULTS: After 4 years of cART start, the cumulative probability of retention in care was 0.80 and survival among patients not lost to follow-up was 0.85. A total of 349 patients (98% of eligible) participated in the cross-sectional evaluation. Ninety per cent were receiving first-line therapy, 29% stavudine- and 58% zidovudine-containing regimens (compared with 94% and 3% at cART initiation). Ninety-three per cent of patients were clinically asymptomatic, and severe lipodystrophy and dyslipidemia were diagnosed in 7.2% and 4.0%, respectively. Good treatment adherence was reported by 83% of patients. Median CD4 T-cell count was 410 cells/µl [IQR 290-511], and 90% of patients had >200 cells/µl. Only 15 (4%) patients had detectable HIV viral load (eight had <200 CD4 cells/µl), five had thymidine analogue mutations, and nine were resistant to two drug classes. In an intention-to-treat analysis, 26.1% (95% CI 22.0-30.5) of patients had failed first-line therapy. CONCLUSIONS: In this Cambodian cohort of adults who started cART at an advanced stage of HIV disease, we observed good clinical and immunovirological outcomes and self-reported treatment adherence at 4 years of therapy.

Full-length genome sequence of a simian immunodeficiency virus (SIV) infecting a captive agile mangabey (Cercocebus agilis) is closely related to SIVrcm infecting wild red-capped mangabeys (Cercocebus torquatus) in Cameroon.

Simian immunodeficiency viruses (SIVs) are lentiviruses that infect an extensive number of wild African primate species. Here we describe for the first time SIV infection in a captive agile mangabey (Cercocebus agilis) from Cameroon. Phylogenetic analysis of the full-length genome sequence of SIVagi-00CM312 showed that this novel virus fell into the SIVrcm lineage and was most closely related to a newly characterized SIVrcm strain (SIVrcm-02CM8081) from a wild-caught red-capped mangabey (Cercocebus torquatus) from Cameroon. In contrast to red-capped mangabeys, no 24 bp deletion in CCR5 has been observed in the agile mangabey. Further studies on wild agile mangabeys are needed to determine whether agile and red-capped mangabeys are naturally infected with the same SIV lineage, or whether this agile mangabey became infected with an SIVrcm strain in captivity. However, our study shows that agile mangabeys are susceptible to SIV infection.

Population pharmacokinetics of emtricitabine in human immunodeficiency virus type 1-infected pregnant women and their neonates.

The objectives of this study were to evaluate emtricitabine (FTC) pharmacokinetics in pregnant women and their neonates and to determine the optimal prophylactic dose for neonates after birth to prevent mother-to-child transmission of human immunodeficiency virus (HIV). A total of 38 HIV-infected pregnant women were administered tenofovir disoproxyl fumarate (300 mg)-FTC (200 mg) tablets-two tablets at the initiation of labor and one daily for 7 days postpartum. By pair, 11 maternal, one cord blood, and two neonatal FTC concentrations were measured using a high-performance liquid chromatography-tandem mass spectrometry validated method and analyzed by a population approach. Model and mean estimates (interpatient variability) were a two-compartment model for mothers, with an absorption rate constant of 0.54 h(-1) (61%), apparent elimination and intercompartmental clearances of 23.2 (17%) and 6.04 liters x h(-1), and apparent central and peripheral volumes of 127 and 237 liters, respectively; an effect compartment linked to maternal circulation for cord blood and a neonatal compartment disconnected, after delivery, with a 10.6-h half-life (30%). After the 400-mg FTC administration, the median population area under the concentration-time curve and the minimal and maximal plasma FTC concentrations in pregnant women were 14.3 mg x liter(-1) x h and 1.68 and 0.076 mg/liter, respectively. At delivery, median (range) predicted maternal and cord blood FTC concentrations were, respectively, 1.16 (0.14 to 1.99) and 0.72 (0.05 to 1.19) mg x liter(-1). We concluded that the 400-mg FTC administration in pregnant women produces higher exposition than does the 200-mg administration in other adults, at steady state. FTC was shown to have good placental transfer (80%). Administering 1 mg FTC/kg as soon as possible after birth or 2 mg/kg 12 h after birth should produce neonatal concentrations comparable to the concentrations observed in adults.

Genetic subspecies diversity of the chimpanzee CD4 virus-receptor gene.

Chimpanzees are naturally and asymptomatically infected by simian immunodeficiency virus (SIV). Pathogenic properties of SIV/HIV vary and differences in susceptibility and pathogenicity of SIV/HIV depend in part on host-specific factors such as virus-receptor/co-receptor interactions. Since CD4 plays a primary role in virus binding and since SIVcpz have been found only in two African chimpanzee subspecies, we characterized the genetic diversity of CD4 receptors in all four recognized subspecies of chimpanzees. We found noticeable variation in the first variable region V1 of CD4 and in intron six among the subspecies of chimpanzees. We found the CD4 receptor to be conserved in individuals belonging to the P. t. verus subspecies and divergent from the other three subspecies, which harbored highly variable CD4 receptors. The CD4 receptor of chimpanzees differed from that of humans. We question whether the observed diversity can explain the species-specific differences in susceptibility to and pathogenicity of SIV/HIV.

Nef-mediated enhancement of virion infectivity and stimulation of viral replication are fundamental properties of primate lentiviruses.

Nef is a multifunctional accessory protein of primate lentiviruses. Recently, it has been shown that the ability of Nef to downmodulate CD4, CD28, and class I major histocompatibility complex is highly conserved between most or all primate lentiviruses, whereas Nef-mediated downregulation of T-cell receptor-CD3 was lost in the lineage that gave rise to human immunodeficiency virus type 1 (HIV-1). Whether or not other Nef activities are preserved between different groups of primate lentiviruses remained to be determined. Here, we show that nef genes from a large variety of HIVs and simian immunodeficiency viruses (SIVs) enhance virion infectivity and stimulate viral replication in human cells and/or in ex vivo infected human lymphoid tissue (HLT). Notably, nef alleles from unpassaged SIVcpz and SIVsmm enhanced viral infectivity, replication, and cytopathicity in cell culture and in ex vivo infected HLT as efficiently as those from HIV-1 and HIV-2, their human counterparts. Furthermore, nef genes from several highly divergent SIVs that have not been found in humans were also highly active in human cells and/or tissues. Thus, most primate lentiviral Nefs enhance virion infectivity and stimulate viral replication. Moreover, our data show that SIVcpz and SIVsmm Nefs do not require adaptive changes to perform these functions in human cells or tissues and support the idea that nef alleles from other primate lentiviruses would also be capable of promoting efficient virus spread in humans.