Virus levels in untreated African infants infected with human immunodeficiency virus type 1

Simian-Human Immunodeficiency Virus SHIV.C.CH505 Persistence in ART-Suppressed Infant Macaques Is Characterized by Elevated SHIV RNA in the Gut and a High Abundance of Intact SHIV DNA in Naive CD4+ T Cells

Mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1) continues to cause new pediatric cases of infection through breastfeeding, a setting where it is not always possible to initiate early antiretroviral therapy (ART). Without novel interventions that do not rely on daily ART, HIV-1-infected children face lifelong medications to control infection. A detailed analysis of virus persistence following breast milk transmission of HIV-1 and ART has not been performed. Here, we used infant rhesus macaques orally infected with simian/human immunodeficiency virus (SHIV) (SHIV.C.CH505) to identify cellular and anatomical sites of virus persistence under ART. Viral DNA was detected at similar levels in blood and tissue CD4+ T cells after a year on ART, with virus in blood and lymphoid organs confirmed to be replication competent. Viral RNA/DNA ratios were elevated in rectal CD4+ T cells compared to those of other sites (P ≤ 0.0001), suggesting that the gastrointestinal tract is an active site of virus transcription during ART-mediated suppression of viremia. SHIV.C.CH505 DNA was detected in multiple CD4+ T cell subsets, including cells with a naive phenotype (CD45RA+ CCR7+ CD95-). While the frequency of naive cells harboring intact provirus was lower than in memory cells, the high abundance of naive cells in the infant CD4+ T cell pool made them a substantial source of persistent viral DNA (approximately 50% of the total CD4+ T cell reservoir), with an estimated 1:2 ratio of intact provirus to total viral DNA. This viral reservoir profile broadens our understanding of virus persistence in a relevant infant macaque model and provides insight into targets for cure-directed approaches in the pediatric population.IMPORTANCE Uncovering the sanctuaries of the long-lived HIV-1 reservoir is crucial to develop cure strategies. Pediatric immunity is distinct from that of adults, which may alter where the reservoir is established in infancy. Thus, it is important to utilize pediatric models to inform cure-directed approaches for HIV-1-infected children. We used an infant rhesus macaque model of HIV-1 infection via breastfeeding to identify key sites of viral persistence under antiretroviral therapy (ART). The gastrointestinal tract was found to be a site for low-level viral transcription during ART. We also show that naive CD4+ T cells harbored intact provirus and were a major contributor to blood and lymphoid reservoir size. This is particularly striking, as memory CD4+ T cells are generally regarded as the main source of latent HIV/simian immunodeficiency virus (SIV) infection of adult humans and rhesus macaques. Our findings highlight unique features of reservoir composition in pediatric infection that should be considered for eradication efforts.

Impact of HIV infection and highly active antiretroviral therapy (HAART) on B cell subpopulations in children

B-cells play an important role in defending children against various infections. In view of scare data, we undertook this prospective cohort study to describe B cell compartment in HIV infected children (<5 years of age) and the effect of HAART on B cell subpopulations. HIV infected children (<5 years) from Pediatric HIV services of the Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, were recruited (April 2012-December 2015). The enrolled HIV-1 infected children (n = 59) were followed up regularly for 12 months; healthy controls (n = 51) included HIV uninfected children with no major illness. Flow cytometry was performed on fresh EDTA-treated blood samples to characterize B cell subpopulations. In HIV-infected children, marked depletion of naive (P = 0.003), non-switched memory (P = 0.02), mature (P = 0.0005), resting memory (P < 0.0001) B cells, and expansion of double negative memory (P < 0.0001), activated memory (P < 0.0001) and tissue like memory (P < 0.0001) B cells were observed as compared to healthy controls. In children started on HAART, at the end of 12 months of therapy, frequencies of non-switched memory (P = 0.04), switched memory (P = 0.01), and resting memory (P = 0.003) B cells were lower; activated memory (P = 0.04), and tissue-like memory (P = 0.0001) B cells were still higher than healthy controls. HIV infection resulted in reduced memory B cells in HIV infected children. Following HAART, there was normalization of some B cell subpopulations. The study emphasizes the need of re-vaccination in HIV infected children to maintain the memory B cell pool and adequate humoral immune response against infections.

Immunity to HIV in Early Life

The developing immune system is adapted to the exposure to a plethora of pathogenic and non-pathogenic antigens encountered in utero and after birth, requiring a fine balance between protective immunity and immune tolerance. In early stages of life, this tolerogenic state of the innate and adaptive immune system and the lack of immunological memory render the host more susceptible to infectious pathogens like HIV. HIV pathogenesis is different in children, compared to adults, with more rapid disease progression and a substantial lack of control of viremia compared to adults. Plasma viral load remains high during infancy and only declines gradually over several years in line with immune maturation, even in rare cases where children maintain normal CD4 T-lymphocyte counts for several years without antiretroviral therapy (ART). These pediatric slow progressors also typically show low levels of immune activation despite persistently high viremia, resembling the phenotype of natural hosts of SIV infection. The lack of immunological memory places the fetus and the newborn at higher risk of infections; however, it may also provide an opportunity for unique interventions. Frequencies of central memory CD4+ T-lymphocytes, one of the main cellular reservoirs of HIV, are very low in the newborn child, so immediate ART could prevent the establishment of persistent viral reservoirs and result in "functional cure." However, as recently demonstrated in the case report of the "Mississippi child" who experienced viral rebound after more than 2 years off ART, additional immunomodulatory strategies might be required for sustained viral suppression after ART cessation. In this review, we discuss the interactions between HIV and the developing immune system in children and the potential implications for therapeutic and prophylactic interventions.

Determinant and outcome of early diagnosis of HIV infection among HIV-exposed infants in southwest Ethiopia

BACKGROUND

Preventing mother-to-child transmission (PMTCT) of human immunodeficiency virus infection (HIV) has been a fundamental advancement in the acquired immunodeficiency syndrome (AIDS) response for the past decade. Several countries have made great strides in the efforts to prevent HIV through mother-to-child transmission. The objective of this study is to assess the determinant and outcome of early diagnosis of HIV infection among HIV-exposed infants in southwest Ethiopia.

METHODS

An institutional based retrospective cohort study was conducted in a hospital. Medical records of HIV-exposed infants and their mothers enrolled into the program were reviewed. Data entry and analysis was carried out using SPSS version 20 for Windows.

RESULTS

A total of 426 HIV exposed infant-mother pairs where both mother and infants received a minimum ARV intervention for PMTCT were included in the study. Two hundred fifty-four (59.6%) of mothers had attended antenatal care (ANC). Of all participants, 234(54.9%) mothers did not receive any PMTCT prophylaxis during ANC, while only 104(24.4) received antiretroviral (ART) as PMTCT prophylaxis and 163(38.3%) claimed that did not observe any infant PMTCT interventions while 135(31.7%) of the infants received single-dose NVP + AZT. About 385(90.4%) infants were not infected at their final infection status. Those mothers who did not attended ANC follow-up, infants on mixed and complementary feeding and infants weaned off and mothers who were in WHO clinical stage III and IV were more likely to have HIV sero positive infant.

CONCLUSION

This study showed that 385(90.4%) of the infants were not infected at their final infection status. Therefore, encouraging pregnant women to visit health facilities during their course of pregnancy, focusing on exclusive breast feeding counseling and promotion, and early initiation of antiretroviral treatment to HIV infected pregnant women are recommend.

Haematological changes in African children who received short-term prophylaxis with nevirapine and zidovudine at birth

We assessed the safety of short-term antiretroviral prophylaxis to prevent mother-to-child transmission (MTCT) of HIV by monitoring haematological changes in children up to the age of 18 months. Babies of HIV-infected women were randomised at birth to receive a single dose of nevirapine (NVP) alone or with zidovudine (ZDV) twice daily for a week. Based on the time of presentation to the labour ward, mothers of these babies might or might not have received intrapartum NVP. Complete blood counts were performed at birth and at 1.5, 3, 6, 9, 12, 15 and 18 months. Babies' HIV status was determined by HIV-1 RNA testing. A total of 1755 babies were included in the study. Age-specific mean haemoglobin levels and prevalence of anaemia (haemoglobin < 10 g/dL) were not significantly different in cases where only the babies received a single dose of NVP and cases where NVP was given to mother/infant pairs or additional ZDV to the baby. Among HIV-infected children compared with uninfected children, the age-specific frequency of anaemia was significantly greater, anaemia started earlier and recovery to normal levels was slower and prolonged. A reversible granulocytopenia was observed in all children between 1.5 and 3 months of age. HIV infection significantly increased the children's risk of death. Antiretroviral prophylaxis appeared to protect against anaemia and child death. Short regimens of antiretrovirals to prevent MTCT of HIV are not associated with long-term adverse haematological changes.

The role of co-infections in mother-to-child transmission of HIV

In HIV-infected women, co-infections that target the placenta, fetal membranes, genital tract, and breast tissue, as well as systemic maternal and infant infections, have been shown to increase the risk for mother-to-child transmission of HIV (MTCT). Active co-infection stimulates the release of cytokines and inflammatory agents that enhance HIV replication locally or systemically and increase tissue permeability, which weakens natural defenses to MTCT. Many maternal or infant co-infections can affect MTCT of HIV, and particular ones, such as genital tract infection with herpes simplex virus, or systemic infections such as hepatitis B, can have substantial epidemiologic impact on MTCT. Screening and treatment for co-infections that can make infants susceptible to MTCT in utero, peripartum, or postpartum can help reduce the incidence of HIV infection among infants and improve the health of mothers and infants worldwide.

The impact of differential antiviral immunity in children and adults

The course of immune maturation has evolved to favour survival at each stage of development in early life. Fetal and neonatal immune adaptations facilitate intrauterine survival and provide early postnatal protection against extracellular pathogens, but they leave infants susceptible to intracellular pathogens such as viruses that are acquired perinatally. This Review focuses on three such pathogens--HIV, hepatitis B virus and cytomegalovirus--and relates the differential impact of these infections in infants and adults to the antiviral immunity that is generated at different ages. A better understanding of age-specific antiviral immunity may inform the development of integrated prevention, treatment and vaccine strategies to minimize the global disease burden resulting from these infections.

Phenotypic characterization of HIV-specific CD8+ T cells during early and chronic infant HIV-1 infection

Although CD8(+) T cells play an important role in the containment of adult HIV-1 replication, their role in infant HIV-1 infection is not as well understood. Impaired HIV-specific CD8(+) T cell responses may underlie the persistently high viral loads observed in infants. We examined the frequency and phenotype of infant HIV-specific CD8(+) T cells in 7 HIV-infected antiretroviral therapy-naïve infants during the first 2 years of life, using class I HLA tetramers and IFN-γ-ELISPOT. The frequency (0.088-3.9% of CD3(+)CD8(+) cells) and phenotype (CD27(+)CD28(-), CD45RA(+/-), CD57(+/-), HLA-DR(+), CD95(+)) of infant HIV-specific CD8(+) T cells were similar to reports in adults undergoing early infection. Unlike adults, at 23-24 months post-infection a high frequency of HIV-specific CD8(+) T cells expressed HLA-DR (mean 80%, range 68-85%) and CD95 (mean 88%, range 79-96%), suggesting sustained activation and vulnerability to apoptosis. Despite comparable expansion of HIV-specific CD8(+) T cells of a similar phenotype to adults during early infection, infant T cells failed to contain HIV-1 replication, and remained persistently activated and vulnerable to apoptosis during chronic infection.

Pediatric HIV-1 in Kenya: pattern and correlates of viral load and association with mortality

BACKGROUND

There is limited information regarding the pattern and correlates of viral replication in vertically HIV-1-infected children and its role on their outcomes in resource-limited settings.

METHODS

HIV-1-infected infants were followed from birth to 24 months. Serial HIV-1 RNA levels were compared in infants infected in utero (<48 hours), peripartum (48 hours-1 month), and late postnatal (after 1 month). Cofactors for viral peak [highest viral load (VL) within 6 months of infection] and set point and mortality were determined.

RESULTS

Among 85 HIV-1-infected infants, 24 were infected in utero, 41 peripartum, 13 late postnatal; 7 had no 48-hour assay. HIV-1 VL set point was significantly lower in infants infected >1 month vs. < or = 1 month (5.59 vs. 6.24 log10 copies per milliliter, P = 0.01). Maternal VL correlated with peak infant VL (P < 0.001). Univariately, infant peak and set point VL and 6-month CD4% <15% predicted mortality; and 6-month CD4% <15% remained independently predictive in multivariate analyses (hazard ratio = 4.85, 95% confidence interval: 1.90 to 12.36).

CONCLUSIONS

Infants infected after the age of 1 month contained virus better than infants infected before 1 month of age. Maternal VL predicted infant VL, which, in turn was associated with early mortality.

RNA Detection and Subtype C Assessment of HIV-1 in Infants with Diarrhea in Ethiopia

In the absence of chemoprophylaxis, HIV-1 transmission occurs in 13-42% of infants born to HIV-1 positive mothers. All exposed infants acquire maternal HIV-1 antibodies that persist for up to 15 months, thereby hampering diagnosis. In resource limited settings, clinical symptoms are the indices of established infection against validated laboratorybased markers. Here we enrolled 1200 children hospitalized for diarrheal and other illnesses. 20-25% of those tested, aged 15 months or younger, were found to be HIV-1-seropositive. Where sufficient plasma was available, HIV-1 RNA detection was performed using a subtype-insensitive assay, with 71.1% of seropositive infants presenting with diarrhea showing positive. From sub-typing analysis, we identified that viruses of the C’ sub-cluster were predominated amongst infants. Although this study may overestimate the HIV-1 frequency through testing symptomatic infants, diarrhea can be seen as a useful marker indicating HIV-1 infection in infants less than 15 months old.

High frequency of rapid immunological progression in African infants infected in the era of perinatal HIV prophylaxis

OBJECTIVES

To determine the natural history of HIV infection following peripartum single-dose nevirapine (sd-NVP) prophylaxis in a resource-limited country, and to assess implications for antiretroviral therapy (ART) roll-out programmes.

METHODS

Infants of HIV-infected mothers in KwaZulu-Natal, South Africa, were tested on days 1 and 28 to detect intrauterine (IU) and intrapartum (IP) infection. Infant follow-up included monthly viral load and CD4 cell measurement. ART was initiated at infant CD4 cell% < or = 20%.

RESULTS

In 740 infants born to 719 HIV-infected women, mother-to-child transmission (MTCT) was 10.3% (69% IU, 31% IP). Median viral load was higher in mothers of infants infected IP than IU (279 000 versus 86 600 copies/ml; P = 0.039) and lower in mothers of uninfected infants (median 26 750 copies/ml; P < 0.001). Peak viraemia was higher in infants infected IP than IU (5 160 000 versus 984 000 copies/ml; P < 0.001). Median viral load at birth in IU-infected infants (155 000 copies/ml) fell 1.4 log to 6510 copies/ml by day 5 and was beneath the detection limit using dried blood spot analysis in 38% of infants. CD4 cell% declined rapidly, to < or = 20% in 70% and < or = 25% in 85% [current World Health Organization (WHO) criteria for initiating ART] of infants by 6 months.

CONCLUSIONS

MTCT was reduced by sd-NVP through an effect on IP transmission. Where MTCT occurred despite NVP, two-thirds of transmissions arose IU; IP-infected babies were born to mothers with very high viral load. Disease progression was particularly rapid, 85% infants meeting WHO criteria for ART within 6 months. These findings argue for more effective MTCT-prevention programmes in resource-limited countries.

Higher In Utero and Perinatal HIV Infection Risk in Girls Than Boys

OBJECTIVE

This study analyzed mother-to-child HIV transmission rates by sex and exposure time for babies born to HIV-infected, untreated African women.

METHODS

Data were analyzed from 2 independent studies done in Malawi during the 1990s. Infections were established by polymerase chain reaction on blood samples. Odds ratios (ORs) for transmission were examined by period at risk: in utero (infected in umbilical cord blood), perinatal (infected in 1st postnatal blood > or =4 weeks), and postnatal (later postnatal infection).

RESULTS

Among 1394 singleton births, girls were more likely to become infected than boys. For in utero transmission, the OR was 1.4 (95% CI: 0.9 to 2.2). For transmission during early life (umbilical cord blood not available) the OR was 2.7 (95% CI: 1.5 to 4.9). However, transmission risks in the perinatal and postnatal infection periods did not differ in boys and girls. Among 303 tested twin-birth pairs, girls were at higher risk than boys for in utero (OR: 2.6; 95% CI: 1.2 to 5.8) and perinatal (OR: 1.9; 95% CI: 1.0 to 3.7) infection. Recognized mother-to-child transmission risk factors did not explain the higher risk of infection in girls.

CONCLUSIONS

Girls were at higher risk of early (in utero and perinatal) HIV infection than boys. It is proposed that minor histocompatibility reactions between maternal lymphocytes and infant Y chromosome-derived antigens reduce the risk of HIV transmission in boys.

Stability of lyophilised specimens for the molecular detection of viral DNA/RNA

BACKGROUND

The range of nucleic acid-based technologies for the molecular detection of pathogens has grown rapidly in recent years. The influx of new testing methods into the clinical laboratory, demands for evaluation and standardisation of methods, interpretation of results and evaluation of laboratory performance have highlighted the need for internal and External Quality Assessment (EQA) systems more than ever before. External Quality Assessment panels demand reproducible, stable specimens of consistent form, suitable for transportation.

OBJECTIVES

To determine the stability of freeze-dried viral specimens in terms of molecular detection.

STUDY DESIGN

When EQA specimens are prepared, they undergo long-term storage and testing as part of the quality control (QC) process. The frequency and nature of testing is dependent on the resources and methodologies available at the time. A range of virus preparations used for EQA was monitored over a period of months to years in a retrospective study; the available quality monitoring data for the five viruses, including storage temperature and method of detection were analysed.

RESULTS

The nucleic acid (DNA or RNA) of the freeze-dried viruses included in the study was readily detectable over a long period of time. Quantitative analysis indicated that detectable concentrations of nucleic acid post-freeze drying were similarly maintained. Storage temperature was an important factor in the stability of HCV, but other viruses were unaffected by storage at different temperatures.

CONCLUSIONS

In summary, the molecular detection of nucleic acid (DNA or RNA) in freeze-dried specimens of HSV1, HSV2, HBV, HCV and HIV is possible even after prolonged storage, in some cases at a range of temperatures. Freeze drying allows large-scale production of viral specimens of high quality for EQA, which are stable in varying storage and shipment conditions. Furthermore, detection of each virus was possible with a range of commonly used molecular diagnostic methods.

Assessing uncertainty in reference intervals via tolerance intervals: application to a mixed model describing HIV infection

We define the reference interval as the range between the 2.5th and 97.5th percentiles of a random variable. We use reference intervals to compare characteristics of a marker of disease progression between affected populations. We use a tolerance interval to assess uncertainty in the reference interval. Unlike the tolerance interval, the estimated reference interval does not contains the true reference interval with specified confidence (or credibility). The tolerance interval is easy to understand, communicate and visualize. We derive estimates of the reference interval and its tolerance interval for markers defined by features of a linear mixed model. Examples considered are reference intervals for time trends in HIV viral load, and CD4 per cent, in HIV-infected haemophiliac children and homosexual men. We estimate the intervals with likelihood methods and also develop a Bayesian model in which the parameters are estimated via Markov-chain Monte Carlo. The Bayesian formulation naturally overcomes some important limitations of the likelihood model.

Pediatric viral human immunodeficiency virus type 1 RNA levels, timing of infection, and disease progression in African HIV-1-infected children

OBJECTIVE

To describe plasma human immunodeficiency virus type 1 (HIV-1) RNA levels in African HIV-1-infected children in relation to the timing of infection and disease progression.

METHODS

A retrospective cohort study was conducted of 80 children who were born to HIV-1-positive mothers and clinically followed from birth to 18 months of age in the ANRS 049 Ditrame project, Abidjan, Côte d'Ivoire (West Africa). The diagnosis and timing of pediatric HIV-1 infection were determined prospectively according to HIV-1 DNA polymerase chain reaction results. A total of 364 HIV-1 RNA viral load (VL) measurements were assessed retrospectively. Kaplan-Meier analyses and proportional hazards models were used to evaluate the prognostic value of pediatric VL and covariates for HIV disease progression or death.

RESULTS

Mean initial positive VL was significantly lower among children who were infected in utero (4.94 log10/mL, n = 12) than in children who were infected later (5.6-6.1 log10/mL, n = 68). In the first 6 months after diagnosis, HIV-1 RNA levels peaked (> or =6 log10/mL), regardless of timing of infection. Then, a slow decline (overall slope, -0.076 log10 copies/mL/mo) was observed until 18 months of age. A 1 log10 higher value of the pediatric peak VL (risk ratio [RR]: 1.85; 95% confidence interval [CI]: 1.0-3.44) and of the maternal VL at delivery (RR: 1.90; CI: 1.16-3.12) were independently associated with an increased risk of rapid progression to acquired immune deficiency syndrome (AIDS) or death at 18 months of life (23 AIDS diagnoses and 31 deaths). Disease progression or death was more rapid for girls than for boys (RR: 2.26; CI: 1.39-4.96).

CONCLUSIONS

In Africa, pediatric HIV-1 RNA levels are very close to those described in industrialized countries and seem to be predictive of AIDS stage or death, as in industrialized countries. With antiretroviral therapy becoming more widely available, the early identification and monitoring of pediatric HIV disease remains of paramount importance in Africa.

Multicenter evaluation of use of dried blood and plasma spot specimens in quantitative assays for human immunodeficiency virus RNA: measurement, precision, and RNA stability

Eleven laboratories evaluated the use of dried blood and plasma spots for quantitation of human immunodeficiency virus (HIV) RNA by two commercially available RNA assays, the Roche Amplicor HIV-1 Monitor and the bioMerieux NucliSens HIV-1 QT assays. The recovery of HIV RNA was linear over a dynamic range extending from 4,000 to 500,000 HIV type 1 RNA copies/ml. The Monitor assay appeared to have a broader dynamic range and seemed more sensitive at lower concentrations. However, the NucliSens assay gave more consistent results and could be performed without modification of the kit. HIV RNA was stable in dried whole blood or plasma stored at room temperature or at -70 degrees C for up to 1 year. Dried blood and dried plasma spots can be used as an easy and inexpensive means for the collection and storage of specimens under field conditions for the diagnosis of HIV infection and the monitoring of antiretroviral therapy.

Primary HIV-1 infection in African children infected through breastfeeding

OBJECTIVES

To describe acute retroviral syndrome and associated primary viraemia in African children infected with HIV-1 through breastfeeding.

DESIGN

Matched case-control study performed retrospectively within the ANRS 049 DITRAME project conducted in 1995-1998 in Abidjan, Côte d'Ivoire.

METHODS

Cases were children infected by HIV-1 postnatally through breastfeeding. All were HIV-1 negative by DNA PCR at least 45 days of age, but positive on a subsequent sample. This period was considered as surrounding the estimated date of postnatal contamination. Signs/symptoms occurring within this period were recorded in cases and compared with those occurring during the same time period in uninfected breastfed children (controls). For cases, plasma specimens were tested for HIV-1 plasma RNA using the branched DNA assay.

RESULTS

Of 22 infants infected postnatally (median age at first positive sample, 185 days; range, 87-373 days), 21 (95.5%) exhibited at least one clinical sign, compared with only 27 of the 44 (61.4%) uninfected children (P = 0.003). Three independent factors were associated with primary HIV-1 infection: mononucleosis-like syndrome [odds ratio (OR), 8.3; 95% confidence interval (CI), 1.4-47.8], dermatitis (OR, 6.0; CI, 1.1-31.9), and generalized lymphadenopathy (OR, 26.5; CI, 2.0-348.4). Among cases, initial median plasma HIV-1 RNA viral load was 5.92 log10 copies/ml; this declined to 4.96 log10 12 months after the first positive viral load.

CONCLUSIONS

These results may be useful for the recognition of early paediatric cases of postnatal transmission in Africa and could enable targeting of those who should benefit from HIV RNA or DNA testing for primary HIV-1 infection and their subsequent care.

Correlates of plasma HIV-1 RNA viral load among HIV-1-seropositive women in Dar es Salaam, Tanzania

This study was conducted to determine the predictors of plasma HIV-1 RNA viral load in HIV-1-positive pregnant women (N = 151) participating in a clinical trial in Tanzania. Viral load was measured at randomization, delivery, and approximately 7 months after delivery. The median viral load was 20,400 copies/mL at baseline, 20,216 copies/mL at delivery, and 19,100 copies/mL 7 months after delivery. The absolute CD4+ lymphocyte count had a strong negative correlation with HIV-1 RNA viral load at baseline (r = -.38), time of delivery (r = -.36), and 7 months after delivery (r = -.53). The association between CD4+ lymphocyte count and HIV-1 RNA viral load was modified by the per capita daily food expenditure in the household, although the difference in viral load became small as the food expenditure in the household increased and was marginally significant at the 75th percentile of the per capita food expenditure. The presence of malaria parasites at baseline was associated with an approximate 116% higher viral load at the three evaluation points (p =.007). Although the long-term effects of malaria on viral load are unknown, prevention of malaria among people living with HIV-1 should be given the highest priority.

Early diagnosis of paediatric HIV-1 infection among African breast-fed children using a quantitative plasma HIV RNA assay

OBJECTIVE

To evaluate the performance of a quantitative plasma HIV-1 RNA assay for HIV infection diagnosis among African breast-fed children.

METHODS

Serial plasma specimens collected in the first week, at day 45-90, 6 months and 9-12 months of age from HIV-exposed children born to HIV-1-infected women enrolled in the DITRAME ANRS 049a perinatal intervention trial (Abidjan, Côte d'Ivoire) were tested for HIV-1 plasma RNA using a branched DNA (bDNA) assay. Sensitivity and specificity of this RNA test were assessed in comparison with a qualitative DNA polymerase chain reaction (PCR) performed on the same blood samples and allowing a reliable detection of the predominant subtype A.

RESULTS

Among 91 samples from 53 infected children which tested positive by DNA PCR, the sensitivity of the bDNA test was 100% [95% confidence interval (CI), 96.0-100.0] at < or = 8 days (n = 19), 6-12 weeks (n = 43), 6 months (n = 26), and 9-12 months (n = 3). The median plasma HIV-1 RNA viral load ranged from 242 000 copies/ml at < or = 8 days to more than 500 000 copies/ml at day 45-90 and at 6 months. Of 106 specimens from 106 uninfected children who were DNA PCR- negative at month 3 or 6 of age, HIV-1 RNA was undetectable in 103, yielding an overall specificity for the bDNA test of 97.2% (95% CI, 92.0-99.4). The viral load in the three remaining samples with false-positive results was low (410, 937 and 3752 copies/ml, respectively).

CONCLUSIONS

The quantitative bDNA assay appears a suitable tool for early, reliable and easy diagnosis of paediatric HIV-1 infection among a population of African breast-fed children.

Viral levels in newborn African infants undergoing primary HIV-1 infection

We examined weekly changes in viral levels in seven untreated infants infected with HIV at birth. Viral levels spiked immediately but reverted quickly to plateau levels typical of infant HIV infection within 2 weeks of first detected viraemia. We speculated that the depletion of naive, susceptible cells is responsible for the rapid decrease in spike levels and that the rapid replacement of lymphocytes in infants causes the high plateau viral levels (10(5) copies/ml) to be sustained.

Prenatal transmission of subtype C HIV-1 in Zimbabwe: HIV-1 RNA and DNA in maternal and cord blood

Maternal and cord samples from HIV-seropositive women and their infants in Zimbabwe, where subtype C is the predominant strain of HIV, were analyzed to determine the frequency of detection of HIV RNA and DNA. HIV RNA was detected in 90% of maternal and in 38% of cord plasma at levels at least 25% of maternal plasma. Heteroduplex mobility assays and sequencing of virus envelope (C2-V5) demonstrated closely related, but unique, subtype C viruses in maternal and cord RNA, and a significantly greater frequency of cord viremia among women with homogenous, compared with heterogeneous viral envelope RNA. Quantification of RNA, measures of envelope viral diversity, and phylogenetic analysis of maternal and cord plasma RNA provide evidence for the frequent exposure and potential transmission of HIV from mother to infant before birth.

Association of HIV-1 load and CD4 lymphocyte count with mortality among untreated African children over one year of age

OBJECTIVE

To examine the association of viral load and CD4 lymphocyte count with mortality among HIV-infected children over one year of age.

DESIGN

A prospective study. HIV-infected children were enrolled during the first year of life and followed for more than 2 years at the Queen Elizabeth Central Hospital in Blantyre, Malawi (southeast Africa).

METHODS

Morbidity and mortality information was collected every 3 months, and physical examination and blood testing (for viral level and CD4 cell percentage) were performed every 6 months. Kaplan-Meier analyses and proportional hazards models were used to estimate survival and to examine the association of primary predictors with mortality.

RESULTS

Of 155 HIV-infected children originally enrolled, 115 (74%) had viral load testing and 82 (53%) had both viral load and CD4 cell percentage testing after their first year. Among children over one year of age, significant associations were found between mortality and the log10 viral load and CD4 cell percentage in both univariate and multivariate models. Independent of the CD4 cell value, a one unit log10 increase in HIV RNA level increased the hazard of child mortality by more than twofold. Children with low CD4 cell counts (< 15%) and high viral loads (> or = 250,000 copies/ml median value) had the worst survival; children with high CD4 cell counts (> or = 15%) and low viral loads (< 250,000 copies/ml) had the best survival.

CONCLUSION

As in developed countries, viral load and CD4 cell count are the main predictors of mortality among African children. Making these tests available adds to the challenges to be considered if antiviral therapies were to be adopted in these countries.