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

Incidence of World Health Organization stage 3 and 4 events, tuberculosis and mortality in untreated, HIV-infected children enrolling in care before 1 year of age: an IeDEA (International Epidemiologic Databases To Evaluate AIDS) East Africa regional analysis

BACKGROUND

Few studies have reported CD4%- and age-stratified rates of World Health Organization Stage 3 (WHO3) events, World Health Organization Stage 4 (WHO4) events, tuberculosis (TB) and mortality in HIV-infected infants before initiation of antiretroviral therapy.

METHODS

HIV-infected children enrolled before 1 year of age in the International Epidemiologic Databases to Evaluate AIDS East Africa region (October 1, 2002, to November, 2008) were included. We estimated incidence rates of earliest clinical event (WHO3, WHO4 and TB), before antiretroviral therapy initiation per local guidelines, stratified by current age (< or ≥6 months) and current CD4% (<15%, 15-24%, ≥25%). CD4%-stratified mortality rates were estimated separately for children who did not experience a clinical event ("background" mortality) and for children who experienced an event, including "acute" mortality (≤30 days post event) and "later" mortality (>30 days post event).

RESULTS

Among 847 children (median enrollment age: 4.8 months; median pre-antiretroviral therapy follow up: 10.8 months; 603 (71%) with ≥1 CD4% recorded), event rates were comparable for those aged <6 and ≥6 months. Current CD4% was associated with risk of WHO4 events for children <6 months of age and with all evaluated events for children ≥6 months old (P < 0.05). "Background" mortality was 3.7-8.4/100 person-years (PY). "Acute" mortality (≤30 days post event) was 33.8/100 PY (after TB) and 41.1/100 PY (after WHO3 or WHO4). "Later" mortality (>30 days post event) ranged by CD4% from 4.7 to 29.1/100 PY.

CONCLUSIONS

In treatment-naïve, HIV-infected infants, WHO3, WHO4 and TB events were common before and after 6 months of age and led to substantial increases in mortality. Early infant HIV diagnosis and treatment are critically important, regardless of CD4%.

Short-term risk of HIV disease progression and death in Ugandan children not eligible for antiretroviral therapy

BACKGROUND

Increasing numbers of HIV-infected children not yet eligible for antiretroviral therapy (ART) are entering health care in Africa. We sought to characterize the risk of short-term disease progression in this population.

METHODS

In a cohort of HIV-infected ART-naive and -ineligible Ugandan children older than 1 year, the rates of clinical/immunologic progression within 2 years were assessed using Kaplan-Meier survival analysis and multivariate Cox proportional-hazards modeling.

RESULTS

Among 192 children (mean age: 6.4 years, CD4%:25), 19% progressed within 2 years by World Health Organization stage 3/4 event (n = 22), death (n = 3), or World Health Organization-defined CD4 threshold for ART initiation (n = 12). Significant univariate predictors were CD4% [hazard ratio (HR) = 2.0 per 10% decrease, P = 0.005], HIV RNA level (HR = 2.4 per log10 increase, P = 0.002), male gender (HR = 2.0, P = 0.04), age < 3 years (HR = 3.7, P = 0.001), CD4 activation (%CD4+ CD38+ HLADR+) (HR = 1.6 per 10% increase, P = 0.05), and CD8 activation (%CD8+ CD38+ HLADR+) (HR = 1.3 per 10% increase, P = 0.05] (HR = 1.3, P = 0.5). In multivariate analysis, CD4% (HR = 2.0, P = 0.034), HIV RNA level (HR = 1.8, P = 0.013), and age < 3 years (HR = 3.0, P = 0.008) were independently predictive. Children with HIV RNA >10 copies per milliliter and CD4% <25 had progression rates of 29% (1 year) and 34% (2 years).

CONCLUSIONS

Even with frequent CD4 monitoring, HIV-infected Ugandan children experienced significant clinical events while ineligible for ART per WHO 2006 guidelines.

Population attributable fractions for late postnatal mother-to-child transmission of HIV-1 in Sub-Saharan Africa

OBJECTIVES

Assess population attributable fractions (PAFs) for late postnatal transmission (LPT) of HIV-1 in a cohort of HIV-1-exposed infants.

METHODS

We used data established from a risk factor analysis of LPT (negative HIV-1 results through the 4-6 week visit, but positive assays thereafter through the 12-month visit) from a perinatal clinical trial conducted in 3 sub-Saharan countries. PAFs were calculated as the proportions of excess LPTs attributed to identified risk factors.

RESULTS

For the cohort of 1317 infants, 206 (15.6%) had only low maternal CD4 counts (<200 cells/mm), 332 (25.2%) had only high maternal plasma viral loads (VLs) (>50,000 copies/mL), and 81 (6.2%) had both low CD4 counts and high VLs. Their PAFs were 26.0% [95% confidence interval (CI): 12.0% to 36.0%], 37.0% (95% CI: 22.0% to 51.0%), and 16.0% (95% CI: 6.0% to 25.0%), respectively.

CONCLUSIONS

Our PAF analysis illustrates the public health impact of the substantial proportion of LPTs accounted for by high-risk women with both low CD4 counts and high VLs. In light of these results, access to and use of antiretroviral therapy by high-risk HIV-1-infected pregnant women is essential. Additional strategies to reduce LPT for those not meeting criteria for antiretroviral therapy should be implemented.

University leadership for innovation in global health and HIV/AIDS diagnostics

Medical products used in the developed world often fail to adequately serve resource-limited settings where electricity, transportation and health care workers are not readily available. We suggest that the problem is not only a lack of coordinated financial resources to purchase existing medical products, but also a lack of products that are specifically designed for resource-limited settings. While donor organisations with a focus on global health are increasingly willing to bear the additional financial risk for the research and development of such high-impact medical products, corporations are still reluctant to take their best scientists and engineers away from more commercially attractive projects. Universities, on the other hand, given their teaching and research missions, are well positioned to engage in such high-risk development projects. A group of biomedical, engineering, business and social science researchers at Northwestern University (NU) propose a creative model to address significant social and health needs. The team's initial product focus is a rapid test for diagnosing infants with HIV. The NU model aligns the incentives and expertise of industry, donors and academia to innovate medical products, such as the infant HIV diagnostic test, for resource-limited settings.

Survival from 9 months of age among HIV-infected and uninfected Zambian children prior to the availability of antiretroviral therapy

BACKGROUND

Few prospective studies have measured survival rates among human immunodeficiency virus (HIV)-infected children in sub-Saharan Africa prior to the availability of antiretroviral therapy.

METHODS

In the context of an observational study of the immunogenicity of measles vaccine in Zambia, we prospectively followed up children from approximately 9 months of age and assessed survival rates, risk factors for mortality, and circumstances at the time of death according to HIV-infection or HIV-exposure status.

RESULTS

There were 56 deaths among 492 study children during follow-up to 3 years of age. Thirty-nine percent of the 105 children with HIV infection died during the study period, compared with 5.0% of the 260 HIV-seropositive but uninfected children and 1.6% of the 127 HIV-seronegative children. Estimated survival probabilities from 9 through 36 months of age were 52% among HIV-infected children, 95% among initially HIV-seropositive but uninfected children, and 98% among HIV-seronegative children. In multivariable analyses, history of a clinic visit within the 4 weeks prior to study entry (adjusted hazard ratio, 4.6; 95% confidence interval, 1.5-13.5), hemoglobin level <8 g/dL at study entry (adjusted hazard ratio, 4.4; 95% confidence interval, 1.5-12.6), and CD4(+) T lymphocyte percentage <15% at study entry (adjusted hazard ratio, 3.2; 95% confidence interval, 1.1-9.5) were associated with mortality among HIV-infected children.

CONCLUSIONS

Only approximately one-half of HIV-infected Zambian children who were alive at 9 months of age survived to 3 years of age, supporting the urgent need for the prevention of mother-to-child transmission of HIV and the early diagnosis and treatment of HIV infection in children in sub-Saharan Africa.

Total lymphocyte count and World Health Organization pediatric clinical stage as markers to assess need to initiate antiretroviral therapy among human immunodeficiency virus-infected children in Moshi, Northern Tanzania

BACKGROUND

The World Health Organization (WHO) has recommended the use of clinical staging alone and with total lymphocyte count to identify HIV infected children in need of antiretroviral therapy (ART) in resource-limited settings, when CD4 cell count is not available.

METHODS

We prospectively enrolled children obtaining care for HIV infection at the Kilimanjaro Christian Medical Centre Pediatric Infectious Diseases Clinic in Moshi, Tanzania between March 2004 and May 2006 for this cohort study.

RESULTS

One hundred ninety two (89.7%) of 214 children met WHO ART initiation criteria based on clinical staging or CD4 cell count. Several low-cost measures identified individuals who met WHO ART initiation criteria to the following degree: WHO stages 3 or 4 had 87.5% (95% CI, 82.8-92.1) sensitivity and, by definition, 100% (CI, 100-100) specificity; WHO recommended advance disease TLC cutoffs: sensitivity = 23.9% (95% CI, 17.3-30.5) specificity = 78.2% (95% CI, 67.3-89.1). Low TLC was a common finding, (50 of 214; 23%); however, it did not improve the sensitivity or specificity of clinical staging in identifying the severely immunosuppressed stage 2 children. Growth failure or use of total lymphocyte counts in isolation were not reliable indicators of severe immunosuppression or need to initiate ART.

CONCLUSION

The use of total lymphocyte count does not improve the ability to identify children in need of ART compared with clinical staging alone. Low absolute lymphocyte count did not correlate with severe immunosuppression based on CD4 cell count in this cohort.

Mortality and associated factors after initiation of pediatric antiretroviral treatment in the Democratic Republic of the Congo

OBJECTIVE

We aimed to describe factors associated with mortality among children receiving antiretroviral treatment (ART) at a pediatric hospital in Kinshasa, Democratic Republic of the Congo.

RESULTS

Two hundred ninety-nine children, <18 years old, were followed for a median of 77 weeks (interquartile range: 61-103) post-ART initiation. Survival probability was 89.6% [95% confidence interval (CI): 85.5-92.6%] at 12 months; 24 of 31 deaths (77.4%) occurred within 2 months of ART initiation. Predictors of mortality in bivariate analysis were >/=2 opportunistic infections before ART initiation, severe immunosuppression as defined by age-specific CD4 count or percentage criteria, hemoglobin <9 g/dL, oral candidiasis, and severe malnutrition. In multivariate analysis, weight for age z-score [hazard ratio (HR): 0.39; 95% CI: 0.27-0.61; P < 0.001] and oral candidiasis (HR: 5.86; 95% CI: 2.34-14.65; P = 0.0002) were independent predictors of mortality. Suspected septic shock was the most common cause of death (n = 12/31, 38.7%).

CONCLUSIONS

Children receiving ART in this resource-poor setting were at the highest risk of dying in the first 2 months of ART, particularly when they presented with malnutrition or oral candidiasis. Optimal timing of ART initiation during nutritional rehabilitation should be determined. Promotion of early care seeking, strengthened health care, and prevention services are important to further improve outcome of pediatric ART in resource-poor settings.

Total lymphocyte count: not a surrogate marker for risk of death in HIV-infected Ugandan children

OBJECTIVES

To determine the utility of total lymphocyte count (TLC) in predicting the 12-month mortality in HIV-infected Ugandan children and to correlate TLC and CD4 cell %.

DESIGN

This is a retrospective data analysis of clinical and laboratory data collected prospectively on 128 HIV-infected children in the HIV Network for Prevention Trials 012 trial.

METHODS

TLC and CD4 cell % measurements were obtained at birth, 14 weeks, and 12, 24, 36, 48, and 60 months of age and assessed with respect to risk of death within 12 months.

RESULTS

Median TLC per microliter (CD4 cell %) was 4150 (41%) at birth, 4900 (24%) at 12 months, 4300 (19%) at 24 months, 4150 (19%) at 36 months, 4100 (18%) at 48 months, and 3800 (20%) at 60 months. The highest risk of mortality within 12 months was 34% - 37% at birth and declined to 13%-15% at 24 months regardless of TLC measurement. The correlation between CD4 cell % and TLC was extremely low overall (r = 0.01).

CONCLUSIONS

The TLC did not predict a risk of progression to death within 12 months in HIV-infected Ugandan children. Therefore, TLC alone may not be a useful surrogate marker for determining those children at highest risk of death, who require antiretroviral therapy most urgently.

Determinants of Survival Without Antiretroviral Therapy After Infancy in HIV-1-Infected Zambian Children in the CHAP Trial

BACKGROUND

There are few data on predictors of HIV progression in untreated children in resource-limited settings.

METHODS

Children with HIV Antibiotic Prophylaxis (CHAP) was a randomized trial comparing cotrimoxazole prophylaxis with placebo in HIV-infected Zambian children. The prognostic value of baseline characteristics was investigated using Cox models.

RESULTS

Five hundred fourteen children aged 1 to 14 (median 5.5) years contributed 607 years follow-up (maximum 2.6 years). Half were boys, and in 67%, the mother was the primary carer; at baseline, median CD4 percentage was 11% and weight was less than third percentile in 67%. One hundred sixty-five children died (27.2 per 100 years at risk; 95% confidence interval 23.3-31.6). Low weight-for-age, CD4 percentage, hemoglobin, mother as primary carer, current malnutrition, and previous hospital admissions for respiratory tract infections or recurrent severe bacterial infections were independent predictors of poorer survival, whereas oral candidiasis predicted poorer survival only when baseline CD4 percentage was not considered. Mortality rates per 100 child years of 44.5 (37.2-53.2), 14.7 (10.9-19.8), and 2.3 (0.3-16.7) were associated with new World Health Organization stages 4, 3, and 1/2, respectively, applied retrospectively; very low weight-for-age was the only staging feature for 42% of stage 4 children.

CONCLUSIONS

Malnutrition and hospitalizations for respiratory/bacterial infections predict mortality independent of immunosuppression, suggesting that they capture HIV- and non-HIV-related mortality, whereas oral candidiasis is a proxy for immunosuppression.

Evolution of virulence: Interdependence, constraints, and selection using nested models

Natural selection acts on virus populations at two distinct but interrelated levels: within individual hosts and between them. Studies of the evolution of virulence typically focus on selection acting at the epidemiological or between-host level and demonstrate the importance of trade-offs between disease transmission and virulence rates. Within-host studies reach similar conclusions regarding trade-offs between transmission and virulence at the level of individual cells. Studies which examine selection at both scales assume that between- and within-host selection are necessarily in conflict. We explicitly examine these ideas and assumptions using a model of within-host viral dynamics nested within a model of between-host disease dynamics. Our approach allows us to evaluate the direction of selection at the within- and between-host levels and identify situations leading to conflict and accord between the two levels of selection.

Use of total lymphocyte count for informing when to start antiretroviral therapy in HIV-infected children: a meta-analysis of longitudinal data

BACKGROUND

Total lymphocyte count has been proposed as an alternative to the percentage of CD4+ T-cells to indicate when antiretroviral therapy should be started in children with HIV in resource-poor settings. We aimed to assess thresholds of total lymphocyte count at which antiretroviral therapy should be considered, and compared monitoring of total lymphocyte count with monitoring of CD4-cell percentage.

METHODS

Longitudinal data on 3917 children with HIV infection were pooled from observational and randomised studies in Europe and the USA. The 12-month risks of death and AIDS by most recent total lymphocyte count and age were estimated by parametric survival models, based on measurements before antiretroviral therapy or during zidovudine monotherapy. Risks were derived and compared at thresholds of total lymphocyte count and CD4-cell percentage for starting antiretroviral therapy recommended in WHO 2003 guidelines.

FINDINGS

Total lymphocyte count was a powerful predictor of the risk of disease progression despite a weak correlation with CD4-cell percentage (r=0.08-0.19 dependent on age). For children older than 2 years, the 12-month risk of death and AIDS increased sharply at values less than 1500-2000 cells per muL, with little trend at higher values. Younger children had higher risks and total lymphocyte count was less prognostic. Mortality risk was substantially higher at thresholds of total lymphocyte count recommended by WHO than at corresponding thresholds of CD4-cell percentage. When the markers were compared at the threshold values at which mortality risks were about equal, total lymphocyte count was as effective as CD4-cell percentage for identifying children before death, but resulted in an earlier start of antiretroviral therapy.

INTERPRETATION

In this population, total lymphocyte count was a strong predictor of short-term disease progression, being only marginally less predictive than CD4-cell percentage. Confirmatory studies in resource-poor settings are needed to identify the most cost-effective markers to guide initiation of antiretroviral therapy.

Sepsis predisposition in children with human immunodeficiency virus

OBJECTIVE

To review predisposition to sepsis in children infected with human immunodeficiency virus (HIV) in the era of highly active antiretroviral therapy (HAART).

DESIGN

Summary of the literature with review by experts in the field.

RESULTS

In industrialized regions, new diagnoses of vertically acquired HIV infection are falling due to perinatal interventions. Provision of HAART has resulted in an enlarging cohort of clinically stable HIV-infected children, with low viral loads and normal CD4 T-lymphocyte counts. Access to HAART in "developed" countries has markedly decreased the rate of progression to acquired immunodeficiency syndrome, the prevalence of organ-specific complications of HIV, the risk of recurrent sepsis, and the high early childhood mortality from HIV infection. There are currently no data on whether initiation of HAART during acute sepsis reduces short-term morbidity or mortality. Undiagnosed, antiretroviral-naive, HIV-infected infants still present sporadically with opportunistic infections such as Pneumocystis jiroveci and cytomegalovirus pneumonia. HIV-infected children have a greater burden of disease due to viral, bacterial, and fungal sepsis, and the case fatality rate for nonopportunistic infections may be greater than in non-HIV-infected children. In "developing" countries, with limited access to HAART, the natural history of HIV infection has altered very little, with the majority of infected children dying from either opportunistic or nonopportunistic disease before 3 yrs of age.

CONCLUSION

Pediatric HIV infection is not a homogeneous condition in the era of HAART. Susceptibility to sepsis, morbidity, and mortality differ according to stage of disease, access to HAART, and virologic and immunologic response to treatment. These issues should be considered if HIV-infected children are to be enrolled and stratified in clinical trials.

Effect of CCR2 chemokine receptor polymorphism on HIV type 1 mother-to-child transmission and child survival in Western Kenya

The effect of CCR2 polymorphism on HIV-1 mother-to-child transmission and disease progression has not been explored in depth within Africa. As the CCR2-64I variant of this putative HIV coreceptor has been associated with slower progression to AIDS in adults, the current study was undertaken to examine the relationship between CCR2 polymorphism and HIV-1 perinatal transmission and child survival in western Kenya. CCR2 genotype was determined for 445 HIV-seropositive mothers and their infants. The CCR2-64I allele frequency of both mothers and children did not differ by HIV-1 transmission status, regardless of maternal viral load, viral subtype, immune status, or placental malaria status. For infants who acquired HIV perinatally (n = 78), there was no association between CCR2 genotype and viral load upon infection or survival rate over the 2-year follow-up. Our results do not indicate an effect of CCR2-64I on perinatal HIV transmission and survival in Kenyan children.

Viral dynamics and CD4+ T cell counts in subtype C human immunodeficiency virus type 1-infected individuals from southern Africa

Defining viral dynamics in natural infection is prognostic of disease progression and could prove to be important for vaccine trial design as viremia may be a likely secondary end point in phase III HIV efficacy trials. There are limited data available on the early course of plasma viral load in subtype C HIV-1 infection in Africa. Plasma viral load and CD4+ T cell counts were monitored in 51 recently infected subjects for 9 months. Individuals were recruited from four southern African countries: Zambia, Malawi, Zimbabwe, and South Africa and the median estimated time from seroconversion was 8.9 months (interquartile range, 5.7-14 months). All were infected with subtype C HIV-1 and median viral loads, measured using branched DNA, ranged from 3.82-4.02 log10 RNA copies/ml from 2-24 months after seroconversion. Viral loads significantly correlated with CD4+ cell counts (r=-0.5, p<0.0001; range, 376-364 cells/mm3) and mathematical modeling defined a median set point of 4.08 log10 (12 143 RNA copies/ml), which was attained approximately 17 months after seroconversion. Comparative measurements using three different viral load platforms (bDNA, Amplicor, and NucliSens) confirmed that viremia in subtype C HIV-1-infected individuals within the first 2 years of infection did not significantly differ from that found in early subtype B infection. In conclusion, the course of plasma viremia, as described in this study, will allow a useful baseline comparator for understanding disease progression in an African setting and may be useful in the design of HIV-1 vaccine trials in southern Africa.

Estimating the net effect of HIV on child mortality in African populations affected by generalized HIV epidemics

For a given prevalence, HIV has a relatively higher impact on child mortality when mortality from other causes is low. To project the effect of the epidemic on child mortality, it is necessary to estimate a realistic schedule of "net" age-specific mortality rates that would operate if HIV were the only cause of child death observable. We assume that this net pattern would be independent of mortality from other causes. We used African studies that measured the survival of HIV-infected children (direct data) or survival of children of HIV-infected mothers (indirect data). We developed a mathematic procedure to estimate the mortality of infected children from indirect data sources and obtained net HIV mortality patterns for each study population. The net age-specific HIV mortality pattern for infected children can be described by a double Weibull curve fitted to empiric data; this gives a functional representation of age-specific mortality rates that decline after infancy and rise in the preteens. The fitted curve that we would expect if HIV were the only effective cause of death shows 67% net survival at 1 year and 39% at 5 years. The curve also predicts 13% net survival at 10 years using constraints based on survival of infected adults.

Child mortality and HIV infection in Africa: a review

OBJECTIVES

To review the available data relating to child mortality in Africa by the HIV infection status of mothers and children.

RESULTS

Child survival is influenced by the HIV epidemic through several mechanisms. Mother-to-child transmission of HIV ranges from 15 to 45%, with up to 15-20% resulting from breastfeeding. HIV-infected children have high mortality rates. For example, a recent community-based study in Rakai, Uganda, showed 2-year mortality rates of 547, 166 and 128 per thousand among HIV-infected children, HIV-negative children of HIV-positive mothers, and HIV-negative children of HIV-negative women, respectively. Child mortality estimates from community-based cohorts demonstrate that the children of HIV-infected mothers have higher mortality rates than the children of uninfected mothers, and that child mortality is closely linked with maternal health status, but because the proportion of vertically infected children is unknown, the value of these studies is limited. Models that use HIV surveillance data together with a set of assumptions indicate that child mortality caused by HIV/AIDS has increased throughout the 1990s to reach close to 10% by 2002.

CONCLUSION

Both disparate trends in HIV prevalence and varying levels of non-HIV-associated child mortality will ensure very different impacts in different countries. To improve the projections of the overall effect that the HIV epidemic will have on child mortality at the population level in countries with generalized epidemics, reliable age-specific mortality rates in infected and uninfected children are needed.

Predictors of early mortality in a cohort of human immunodeficiency virus type 1-infected african children

BACKGROUND

Pediatric human immunodeficiency virus type 1 (HIV-1) infection follows a bimodal clinical course with rapid progression in 10-45% of children before the age of 2 years and slower progression in the remainder. A prospective observational study was undertaken to determine predictors of mortality in HIV-1-infected African infants during the first 2 years of life.

METHODS

Infants in a perinatal cohort identified to be HIV-1-infected by DNA PCR were followed monthly to 1 year, then quarterly to 2 years or death.

RESULTS

Among 62 HIV-1-infected infants, infection occurred by the age of 1 month in 56 (90%) infants, and 32 (52%) died at median age of 6.2 months. All infant deaths were caused by infectious diseases, most frequently pneumonia (75%) and diarrhea (41%). Univariate predictors of infant mortality included maternal CD4 count <200 cells/microl [hazard ratio (HR), 3.4; P = 0.008], maternal anemia (HR = 3.7; P = 0.005), delivery complications (HR = 2.7; P = 0.01), low birth weight (HR = 4.1; P = 0.001), weight, length and head circumference </=5th percentile at age 1 month (HR = 3.7, P = 0.003; HR = 5.8, P < 0.001; and HR = 10.4, P < 0.001, respectively), formula-feeding (HR = 4.0; P = 0.01), infant CD4% </=15% (HR = 5.5; P = 0.01), infant CD4 count <750 (HR = 9.7; P = 0.006) and maternal death (HR = 2.9, P = 0.05). In multivariate analysis, maternal CD4 count <200 (HR = 2.7; P = 0.03) and delivery complications (HR = 3.4; P = 0.005) were independently associated with infant mortality.

CONCLUSIONS

Advanced maternal HIV disease, maternal anemia, delivery complications, early growth faltering, formula-feeding and low infant CD4 were predictors of early mortality in African HIV-1-infected infants. In resource-poor settings, these predictors may be useful for early identification and treatment of high risk infants.

Polymorphism of Fc receptor IIa for IgG in infants is associated with susceptibility to perinatal HIV-1 infection

OBJECTIVE

To evaluate the effect of polymorphism of the Fc gamma receptor IIa, which is associated with differential human IgG subclass binding, on perinatal HIV-1 transmission.

METHODS

Fc gamma RIIa genotype was tested in 448 HIV-seropositive mothers and their infants from a cohort study designed to assess the effect of placental malaria on HIV vertical transmission conducted from 1996 to 2001 in western Kenya. Fc gamma RIIa polymorphism was analyzed for associations with susceptibility to perinatal HIV infection and all-cause child mortality in HIV-positive children.

RESULTS

Overall, 20% of infants were perinatally infected with HIV. There was no statistically significant association between maternal genotype and perinatal HIV-1 transmission. However, frequency of the infant Fc gamma RIIa His/His131 genotype was higher in HIV-positive compared with HIV-negative infants (35% and 21%, respectively), whereas the distribution was reversed (15% and 28%, respectively) for infants with the Fc gamma RIIa Arg/Arg131 genotype. Multivariate logistic regression controlling for maternal and infant confounding factors demonstrated that the odds of perinatal HIV infection in infants with the Fc gamma RIIa His/His131 versus Fc gamma RIIa His/Arg131 genotypes were significantly higher (adjusted odds ratio, 2.22; 95% confidence interval, 1.23-4.02; P = 0.009). There was no evidence for an association between HIV-positive child all-cause mortality and Fc gamma RIIa genotype.

CONCLUSIONS

This study provides the first evidence that the infant Fc gamma RIIa His/His131 genotype is associated with susceptibility to perinatal HIV-1 transmission and further suggests that there is a dose-response relationship for the effect of the Fc gamma RIIa His131 gene on transmission.

Alternatives to HIV-1 RNA concentration and CD4 count to predict mortality in HIV-1-infected children in resource-poor settings

Cheaper, simpler alternatives to CD4 lymphocyte count and HIV-1 RNA detection for assessing the prognosis of HIV-1 infection are needed for resource-poor settings. However, little is known about the predictive value of alternative assays, in particular in children. We assessed the prognostic value of total lymphocyte count, immune complex-dissociated p24 antigen, white blood cell count, packed-cell volume (haematocrit), and serum albumin for mortality in 376 HIV-1-infected, mainly African-American or Hispanic children enrolled during March, 1988 to January, 1991. In a Cox proportional hazards model, including all assay-alternatives to CD4 and RNA, total lymphocyte count (p<0.0001) and serum albumin (p=0.0107) independently predicted mortality. Further assessment of these markers is warranted in resource-poor settings.

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.

Comparison of human immunodeficiency virus type 1 viral loads in Kenyan women, men, and infants during primary and early infection

Steady-state levels of human immunodeficiency virus type 1 (HIV-1) RNA in plasma reached at approximately 4 months postinfection are highly predictive of disease progression. Several studies have investigated viral levels in adults or infants during primary and early infection. However, no studies have directly compared these groups. We compared differences in peak and set point plasma HIV-1 RNA viral loads among antiretrovirus-naive Kenyan infants and adults for whom the timing of infection was well defined. Peak and set point viral loads were significantly higher in infants than in adults. We did not observe any gender-specific differences in viral set point in either adults or infants. However, infants who acquired HIV-1 in the first 2 months of life, either in utero, intrapartum, or through early breast milk transmission, had significantly higher set point HIV-1 RNA levels than infants who were infected after 2 months of age through late breast milk transmission or adults who were infected through heterosexual transmission.

The long-term impact of HIV and orphanhood on the mortality and physical well-being of children in rural Malawi

OBJECTIVE

To assess the influence of maternal HIV status and orphanhood on child mortality and physical well-being.

DESIGN

Retrospective cohort study with > 10 years of follow-up.

METHODS

From population-based surveys in Karonga District, Malawi in the 1980s, 197 individuals were identified as HIV-positive. These individuals and 396 HIV-negative individuals matched for age and sex, and their spouses and offspring, were sought in 1998-2000.

RESULTS

All but 11 of the index individuals were traced, identifying 2520 offspring; of these, 1106 offspring were included in analyses. Among those with HIV-positive mothers, mortality was 27% [95% confidence interval (CI), 17-38] in infants (1-30 days), 46% (95% CI, 34-58) in those under 5 years and 49% (95% CI, 38-61) in those under 10 years. The corresponding figures for those with HIV-negative mothers were 11% (95% CI, 8-13), 16% (95% CI, 13-19) and 17% (95% CI, 14-20). Death of HIV-positive mothers, but not of HIV-negative mothers or of fathers, was associated with increased child mortality. Among survivors who were still resident in the district, neither maternal HIV status nor orphanhood was associated with stunting, being wasted, or reported ill-health.

CONCLUSIONS

Mortality in children under 5 years is much higher in children born to HIV-positive mothers than in those born to HIV-negative mothers. With 10% of pregnant women HIV-positive, we estimate that approximately 18% of under-5 deaths in this population are attributable to HIV. Most of the excess is attributable to vertical transmission of HIV. Our findings suggest that, in terms of physical well-being, the extended family in this society has not discriminated against surviving children whose parents have been ill or have died as a result of HIV/AIDS.

The state of immunology in Africa: HIV/AIDS and malaria

HIV and malaria are two major infections that are responsible for the greatest burden of diseases, morbidity and mortality in the African population. Successful research has been undertaken in Africa into novel means of monitoring HIV disease progression and in identifying vaccine candidates. The role of IgG isotypes in malaria has been investigated, as have parasite adhesion molecules important for pathogenesis. It is hoped that vaccines for malaria will soon prove successful. However, many problems still face immunology research in Africa.

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.

Severe, rapidly progressive human immunodeficiency virus type 1 disease in newborns with coinfections

AIM

To describe a severe form of rapidly progressive HIV-1 infection manifesting in the neonatal period.

METHOD

Prospective cohort study, King Edward VIII Hospital, Durban, South Africa. HIV-1-exposed neonates with hepatosplenomegaly, lymphadenopathy or persistent pneumonia within the first 28 days of life were investigated for perinatal infections. Confirmation of neonatal HIV-1 infection, HIV-1 subtype and clinical outcomes were studied.

RESULTS

Twenty-three (72%) of 32 symptomatic HIV-1-exposed neonates recruited at a mean of 15.2 days were HIV-1-infected. HIV-1 infection was detected in 5 patients who were tested within 48 h of birth, confirming congenital infection. Congenital infection was not excluded in any case. Median neonatal viral load at recruitment was 471,932 copies/ml and median CD4 was 777 cells/mm3. The predominant clinical presentation was growth retardation and prematurity. Perinatal infections detected included: tuberculosis (8), syphilis (6) and cytomegalovirus (10). All of the neonates with perinatal tuberculosis were HIV-1-coinfected. Maternal and neonatal viral load and CD4 at recruitment were not statistically different between the groups with tuberculosis vs. other coinfections. Gag gene sequence analysis confirmed closely aligned HIV-1 subtype C in mothers and neonates. Nineteen (83%) died by 9 months, with a mean age at death of 3.5 months.

CONCLUSIONS

A distinct group of HIV-1-infected babies may clinically manifest in the neonatal period with perinatal coinfections, subsequent rapidly progressive HIV-1 and early death.