Use of the polymerase chain reaction for early detection of the proviral sequences of human immunodeficiency virus in infants born to seropositive mothers. New York City Collaborative Study of Maternal HIV Transmission and Montefiore Medical Center HIV Perinatal Transmission Study Group

Diagnosis of Human Immunodeficiency Virus Infection

HIV diagnostics have played a central role in the remarkable progress in identifying, staging, initiating, and monitoring infected individuals on life-saving antiretroviral therapy. They are also useful in surveillance and outbreak responses, allowing for assessment of disease burden and identification of vulnerable populations and transmission "hot spots," thus enabling planning, appropriate interventions, and allocation of appropriate funding. HIV diagnostics are critical in achieving epidemic control and require a hybrid of conventional laboratory-based diagnostic tests and new technologies, including point-of-care (POC) testing, to expand coverage, increase access, and positively impact patient management. In this review, we provide (i) a historical perspective on the evolution of HIV diagnostics (serologic and molecular) and their interplay with WHO normative guidelines, (ii) a description of the role of conventional and POC testing within the tiered laboratory diagnostic network, (iii) information on the evaluations and selection of appropriate diagnostics, (iv) a description of the quality management systems needed to ensure reliability of testing, and (v) strategies to increase access while reducing the time to return results to patients. Maintaining the central role of HIV diagnostics in programs requires periodic monitoring and optimization with quality assurance in order to inform adjustments or alignment to achieve epidemic control.

PEPFAR scale-up of pediatric HIV services: innovations, achievements, and challenges

HIV/AIDS has had a profound impact on children around the world since the start of the epidemic. There are currently 3.4 million children under the age of 15 years living with HIV globally, and more than 450,000 children currently receiving lifesaving antiretroviral treatment. This article describes efforts supported by the President's Emergency Plan for AIDS Relief (PEPFAR) to expand access to treatment for children living with HIV in high-burden countries. The article also highlights a series of case studies that illustrate the impact that the PEPFAR initiative has had on the pediatric HIV epidemic. Through its support of host governments and partner organizations, the PEPFAR initiative has expanded HIV testing and treatment for pregnant women to reduce vertical transmission of HIV, increased access to early infant diagnosis for HIV-exposed infants, improved training and resources for clinicians who provide pediatric care and antiretroviral treatment, and, through public-private partnerships with pharmaceutical manufacturers, helped increase the number of medications available for the treatment of HIV-infected children in resource-limited settings.

Diagnosis of HIV-1 infection in infants using dried blood spots in Tamil Nadu, South India

INTRODUCTION

Diagnosis of HIV infection in infants is difficult due to the presence of maternal antibodies; only nucleic acid assays are very helpful in early detection. Filter papers are especially useful for blood collection in resource-poor settings with limited access to diagnostic facilities. MATERIALS #ENTITYSTARTX00026;

METHODS

DBS samples were collected from the infants born to HIV seropositive mothers who had received single dose nevirapine at onset of labor. The samples were directly spotted onto the Whatman 903 cards from heel, big toe or finger prick depending on the age of the infants. A total of 766 infant samples were collected on dried blood spots (DBS) and transported to the Department of Experimental Medicine (DEM), Chennai, for testing from different government hospitals of rural and urban parts of Tamil Nadu, South India. According to National AIDS Control Organization's (NACO) protocol DNA was extracted from all these DBS and PCR was performed using the Roche kit version 1.5.

RESULTS

Fifteen infants were found to be HIV positive and 751 were HIV negative; all these 15 positive infants and 49 negative infants who were in the age group between 10 and 18 months were repeated with another DBS and compared with whole blood. The DBS results were concordant with the whole blood method and the sensitivity and specificity were 100%.

HIV rapid testing as a key strategy for prevention of mother-to-child transmission in Brazil

OBJECTIVE

To assess the feasibility of HIV rapid testing for pregnant women at maternity hospital admission and of subsequent interventions to reduce perinatal HIV transmission.

METHODS

Study based on a convenience sample of women unaware of their HIV serostatus when they were admitted to delivery in public maternity hospitals in Rio de Janeiro and Porto Alegre, Brazil, between March 2000 and April 2002. Women were counseled and tested using the Determine HIV1/2 Rapid Test. HIV infection was confirmed using the Brazilian algorithm for HIV infection diagnosis. In utero transmission of HIV was determined using HIV-DNA-PCR. There were performed descriptive analyses of sociodemographic data, number of previous pregnancies and abortions, number of prenatal care visits, timing of HIV testing, HIV rapid test result, neonatal and mother-to-child transmission interventions, by city studied.

RESULTS

HIV prevalence in women was 6.5% (N=1,439) in Porto Alegre and 1.3% (N=3.778) in Rio de Janeiro. In Porto Alegre most of women were tested during labor (88.7%), while in Rio de Janeiro most were tested in the postpartum (67.5%). One hundred and forty-four infants were born to 143 HIV-infected women. All newborns but one in each city received at least prophylaxis with oral zidovudine. It was possible to completely avoid newborn exposure to breast milk in 96.8% and 51.1% of the cases in Porto Alegre and Rio de Janeiro, respectively. Injectable intravenous zidovudine was administered during labor to 68.8% and 27.7% newborns in Porto Alegre and Rio de Janeiro, respectively. Among those from whom blood samples were collected within 48 hours of birth, in utero transmission of HIV was confirmed in 4 cases in Rio de Janeiro (4/47) and 6 cases in Porto Alegre (6/79).

CONCLUSIONS

The strategy proved feasible in maternity hospitals in Rio de Janeiro and Porto Alegre. Efforts must be taken to maximize HIV testing during labor. There is a need of strong social support to provide this population access to health care services after hospital discharge.

Dried blood spots for the diagnosis and quantitation of HIV-1: stability studies and evaluation of sensitivity and specificity for the diagnosis of infant HIV-1 infection in Thailand

Molecular methods for HIV-1 infection using dried blood-spot (DBS) for HIV-1 CRF01_AE subtypes have not been fully optimized. In this study assays for HIV-1 diagnosis or quantitation were evaluated using infant DBS from Thailand. Paired DBS and whole blood samples from 56 HIV-1 CRF01_AE or B'-infected infants were tested for infant diagnosis using modified Amplicor DNA PCR and NucliSens RNA NASBA and an in-house real-time PCR assay. The Amplicor Monitor viral load (VL) assay, with modifications for DBS, was also evaluated. DBS VL were hematocrit corrected. Stability studies were done on DBS stored at -70 degrees C to 37 degrees C for up to 1 year. The DBS diagnostic assays were 96-100% sensitive and 100% specific for HIV-1 diagnosis. DBS HIV-1 VL were highly correlated with plasma VL when corrected using the actual or an assumed hematocrit factor (r(c)=0.88 or 0.93, respectively). HIV-1 DNA in DBS appeared to be more stable than RNA and could be detected after up to 9 months at most temperatures. DBS VL could be consistently determined when stored frozen. These results show that DBS can be used accurately instead of whole blood for the diagnosis of HIV-1 infection and VL quantitation, particularly if samples are appropriately stored.

THE VERTICAL TRANSMISSION OF HUMAN IMMUNODEFICIENCY VIRUS TYPE 1: Molecular and Biological Properties of the Virus

The vertical (mother-to-infant) transmission of human immunodeficiency virus type 1 (HIV-1 ) occurs at an estimated rate of more than 30% and is the major cause of AIDS in children. Numerous maternal parameters, including advanced dinical stages, low CD4+ lymphocte counts, high viral load, immune response, and disease progression have been implicated in an increased risk of vertical transmission. While the use of antiretroviral therapy (ART) during pregnancy has been shown to reduce the risk of vertical transmission, selective transmission of ART-resistant mutants has also been documented. Elucidation of the molecular mechanisms of vertical transmission might provide relevant information for the development of effective strategies for prevention and treatment. By using HIV-1 infected mother-infant pairs as a transmitter-recipient model, the minor genotypes of HIV-1 with macrophage-tropic and non-syncytium-inducing phenotypes (R5 viruses) in infected mothers were found to be transmitted to their infants and were initially maintained in the infants with the same properties. In addition, the transmission of major and multiple genotypes has been suggested. Furthermore, HIV-1 sequences found in non-transmitting mothers (mothers who failed to transmit HIV-1 to their infants in the absence of ART) were less heterogeneous than those from transmitting mothers, suggesting that viral heterogeneity may play an important role in vertical transmission. In the analysis of other regions of the HIV-1 genome, we have shown a high conservation of intact and functional gag p17, vif, vpr, vpu, tat, and nef open reading frames following mother-to-infant transmission. Moreover the accessory genes, vif and vpr, were less functionally conserved in the isolates of non-transmitting mothers than transmitting mothers and their infants. We, therefore, should target the properties of transmitted viruses to develop new and more effective strategies for the prevention and treatment of HIV-1 infection.

Reduced mortality associated with breast-feeding-acquired HIV infection and breast-feeding among HIV-infected children in Zambia

OBJECTIVES

In developing countries, where mother-to-child transmission of HIV through breast-feeding is common, little is known about the impact of postpartum transmission on child survival. This study assessed whether children infected postpartum have longer survival from time of infection versus those infected during gestation or delivery.

DESIGN

We used a prospective cohort study to analyze data from 213 HIV-infected children enrolled in a breast-feeding intervention trial in Lusaka, Zambia (2001 to 2004).

METHODS

We compared mortality 1 year after HIV infection in children stratified by age of infection: 0 to 3 days (intrauterine [IU] group), 4 to 40 days (intrapartum/early postpartum [IP/EPP] group), and >40 days (postpartum [PP] group).

RESULTS

A total of 61, 71, and 81 children were infected in the IU, IP/EPP, and PP groups, respectively. Children with intrauterine or intrapartum/early postpartum transmission had higher mortality over the first 12 months after infection than children with postpartum transmission (P = 0.001 and P = 0.006, respectively); no differences were detected between children with intrauterine and intrapartum/early postpartum transmission. Nearly 20% of the IU and IP/EPP groups died by 100 days after infection, whereas nearly 10% of the PP group had died by this time. After adjusting for birth weight, maternal CD4 cell count, breast-feeding, and maternal death, children infected postpartum had one quarter the mortality rate (hazard ratio [HR] = 0.27, 95% confidence interval [CI]: 0.15 to 0.50) of those infected in utero. Stopping breast-feeding increased mortality in infected children (HR = 3.1, 95% CI: 1.8 to 5.3).

CONCLUSIONS

This study demonstrates a survival benefit among children infected postpartum versus children infected during pregnancy or delivery and a benefit to increased breast-feeding duration among infected children. Testing children for HIV early may provide a means to allow for earlier intervention.

Diagnosis of HIV-1 infection in children younger than 18 months in the United States

The objectives of this technical report are to describe methods of diagnosis of HIV-1 infection in children younger than 18 months in the United States and to review important issues that must be considered by clinicians who care for infants and young children born to HIV-1-infected women. Appropriate HIV-1 diagnostic testing for infants and children younger than 18 months differs from that for older children, adolescents, and adults because of passively transferred maternal HIV-1 antibodies, which may be detectable in the child's bloodstream until 18 months of age. Therefore, routine serologic testing of these infants and young children is generally only informative before the age of 18 months if the test result is negative. Virologic assays, including HIV-1 DNA or RNA assays, represent the gold standard for diagnostic testing of infants and children younger than 18 months. With such testing, the diagnosis of HIV-1 infection (as well as the presumptive exclusion of HIV-1 infection) can be established within the first several weeks of life among nonbreastfed infants. Important factors that must be considered when selecting HIV-1 diagnostic assays for pediatric patients and when choosing the timing of such assays include the age of the child, potential timing of infection of the child, whether the infection status of the child's mother is known or unknown, the antiretroviral exposure history of the mother and of the child, and characteristics of the virus. If the mother's HIV-1 serostatus is unknown, rapid HIV-1 antibody testing of the newborn infant to identify HIV-1 exposure is essential so that antiretroviral prophylaxis can be initiated within the first 12 hours of life if test results are positive. For HIV-1-exposed infants (identified by positive maternal test results or positive antibody results for the infant shortly after birth), it has been recommended that diagnostic testing with HIV-1 DNA or RNA assays be performed within the first 14 days of life, at 1 to 2 months of age, and at 3 to 6 months of age. If any of these test results are positive, repeat testing is recommended to confirm the diagnosis of HIV-1 infection. A diagnosis of HIV-1 infection can be made on the basis of 2 positive HIV-1 DNA or RNA assay results. In nonbreastfeeding children younger than 18 months with no positive HIV-1 virologic test results, presumptive exclusion of HIV-1 infection can be based on 2 negative virologic test results (1 obtained at > or = 2 weeks and 1 obtained at > or = 4 weeks of age); 1 negative virologic test result obtained at > or = 8 weeks of age; or 1 negative HIV-1 antibody test result obtained at > or = 6 months of age. Alternatively, presumptive exclusion of HIV-1 infection can be based on 1 positive HIV-1 virologic test with at least 2 subsequent negative virologic test results (at least 1 of which is performed at > or = 8 weeks of age) or negative HIV-1 antibody test results (at least 1 of which is performed at > or = 6 months of age). Definitive exclusion of HIV-1 infection is based on 2 negative virologic test results, 1 obtained at > or = 1 month of age and 1 obtained at > or = 4 months of age, or 2 negative HIV-1 antibody test results from separate specimens obtained at > or = 6 months of age. For both presumptive and definitive exclusion of infection, the child should have no other laboratory (eg, no positive virologic test results) or clinical (eg, no AIDS-defining conditions) evidence of HIV-1 infection. Many clinicians confirm the absence of HIV-1 infection with a negative HIV-1 antibody assay result at 12 to 18 months of age. For breastfeeding infants, a similar testing algorithm can be followed, with timing of testing starting from the date of complete cessation of breastfeeding instead of the date of birth.

Pediatric HIV infection: immune and viral evaluation

Advances in laboratory methods have driven improvements in the management and treatment of HIV infection. The methods to accurately and rapidly diagnose HIV infection in infants and children have been outlined in the previous article. In this review, the laboratory evaluation of infected children is described and methods to monitor progression of disease and response to therapy outlined.

Segregation of human immunodeficiency virus type 1 subtypes by risk factor in Australia

The aim of this study was to determine which human immunodeficiency virus type 1 (HIV-1) subtypes were circulating in Australia and to correlate the subtypes with risk factors associated with the acquisition of HIV-1 infection. DNA was extracted from peripheral blood mononuclear cells, and HIV-1 env genes were amplified and subtyped using heteroduplex mobility analysis, with selected samples sequenced and phylogenetic analysis performed. The HIV-1 env subtypes were determined for 141 samples, of which 40 were from female patients and 101 were from male patients; 13 samples were from children. Forty-seven patients were infected by homosexual or bisexual contact, 46 were infected through heterosexual contact, 21 were infected from injecting drug use (IDU), 13 were infected by vertical transmission, 8 were infected from nosocomial exposure, and 6 were infected by other modes of transmission, including exposure to blood products, ritualistic practices, and two cases of intrafamilial transmission. Five subtypes were detected; B (n = 104), A (n = 5), C (n = 17), E (CRF01_AE; n = 13), and G (n = 2). Subtype B predominated in HIV-1 acquired homosexually (94% of cases) and by IDU (100%), whereas non-subtype B infections were mostly seen in heterosexually (57%) or vertically (22%) acquired HIV-1 infections and were usually imported from Africa and Asia. Subtype B strains of group M viruses predominate in Australia in HIV-1 transmitted by homosexual or bisexual contact and IDU. However, non-B subtypes have been introduced, mostly acquired via heterosexual contact.

The chemical bases of the various AIDS epidemics: recreational drugs, anti-viral chemotherapy and malnutrition

In 1981 a new epidemic of about two-dozen heterogeneous diseases began to strike non-randomly growing numbers of male homosexuals and mostly male intravenous drug users in the US and Europe. Assuming immunodeficiency as the common denominator the US Centers for Disease Control (CDC) termed the epidemic, AIDS, for acquired immunodeficiency syndrome. From 1981-1984 leading researchers including those from the CDC proposed that recreational drug use was the cause of AIDS, because of exact correlations and of drug-specific diseases. However, in 1984 US government researchers proposed that a virus, now termed human immunodeficiency virus (HIV), is the cause of the non-random epidemics of the US and Europe but also of a new, sexually random epidemic in Africa. The virus-AIDS hypothesis was instantly accepted, but it is burdened with numerous paradoxes, none of which could be resolved by 2003: Why is there no HIV in most AIDS patients, only antibodies against it? Why would HIV take 10 years from infection to AIDS? Why is AIDS not self-limiting via antiviral immunity? Why is there no vaccine against AIDS? Why is AIDS in the US and Europe not random like other viral epidemics? Why did AIDS not rise and then decline exponentially owing to antiviral immunity like all other viral epidemics? Why is AIDS not contagious? Why would only HIV carriers get AIDS who use either recreational or anti-HIV drugs or are subject to malnutrition? Why is the mortality of HIV-antibody-positives treated with anti-HIV drugs 7-9%, but that of all (mostly untreated) HIV-positives globally is only 1.4%? Here we propose that AIDS is a collection of chemical epidemics, caused by recreational drugs, anti-HIV drugs, and malnutrition. According to this hypothesis AIDS is not contagious, not immunogenic, not treatable by vaccines or antiviral drugs, and HIV is just a passenger virus. The hypothesis explains why AIDS epidemics strike non-randomly if caused by drugs and randomly if caused by malnutrition, why they manifest in drug- and malnutrition-specific diseases, and why they are not self-limiting via anti-viral immunity. The hypothesis predicts AIDS prevention by adequate nutrition and abstaining from drugs, and even cures by treating AIDS diseases with proven medications.

Maternal health factors and early pediatric antiretroviral therapy influence the rate of perinatal HIV-1 disease progression in children

OBJECTIVE

To determine the relationship of maternal health factors and infant antiretroviral treatment to the risk of pediatric disease progression to AIDS or death by 24 months of age.

DESIGN

Prospective perinatal HIV-1 transmission and pediatric natural history study.

SETTING

Urban medical centers in four cities in the USA.

PARTICIPANTS

A total of 2656 pregnant and postpartum HIV-infected women enrolled in the Perinatal AIDS Collaborative Transmission Study (PACTS) and 360 children determined to be HIV-infected.

MAIN OUTCOME MEASURES

Pediatric AIDS or death by 24 months of age.

RESULTS

Children born to mothers with class C disease, CD4 cell count < 200 x 106/l, or HIV-1 RNA viral load > 100 000 copies/ml progressed more rapidly than children born to mothers with less advanced disease. In a multivariate analysis, there was an increased risk of progression if mothers had Class C disease [relative risk (RR), 1.7; 95% confidence interval (CI), 1.0-2.7] or HIV-1 RNA > 100 000 copies/ml (RR, 2.4; 95% CI, 1.2-4.6) controlling for child antiretroviral therapy and year of birth. Earlier years of birth significantly increased the likelihood of rapid progression (P = 0.01) in this multivariate model. Children who received combination antiretroviral therapies with a protease inhibitor or non-nucleoside reverse transcriptase inhibitor were significantly less likely to progress compared with those receiving no therapy (P = 0.03).

CONCLUSIONS

HIV-1-infected infants born to women with advanced HIV-1 disease were at increased risk for rapid disease progression. More recent birth year and early treatment with potent antiretroviral therapy significantly diminished the likelihood of developing AIDS or dying during early childhood.

Human immunodeficiency virus type 1 RNA polymerase chain reaction reasonably excludes infection in exposed infants

A nucleic acid sequence-based amplification (NASBA) assay that detects HIV RNA may be helpful in excluding perinatal HIV infection. We reviewed the records of 190 infants born to HIV-infected mothers. The sensitivity and specificity of the NASBA assay were 100% when measured at two time periods in the first 9 months of life. The HIV RNA NASBA assay should be considered a valid diagnostic test in this population.

Human herpesvirus 6 variant a infects human term syncytiotrophoblasts in vitro and induces replication of human immunodeficiency virus type 1 in dually infected cells

Human herpesvirus 6 (HHV-6) and human immunodeficiency virus type 1 (HIV-1) may interact during transplacental transmission of HIV-1. The placental syncytiotrophoblast layer serves as the first line of defense of the fetus against viruses. Patterns of replication of HHV-6 variant A (HHV-6A) and HIV-1 were analyzed in singly and dually infected human term syncytiotrophoblast cells cultured in vitro. For this purpose, the GS strain of HHV-6A and the Ba-L and IIIB strains of HIV-1 were used. HHV-6A replication was restricted at the level of early gene products in singly infected syncytiotrophoblasts, whereas no viral protein expression was found in cells infected with HIV-1 alone. Coinfection of syncytiotrophoblast cells with HHV-6A and HIV-1 resulted in production of infectious HIV-1. In contrast, no enhancement of HHV-6A expression was observed in cell cultures infected with both viruses. Uninfected syncytiotrophoblast cells were found to express CXCR4 and CCR3 but not CD4 or CCR5 receptors. Infection of syncytiotrophoblasts with HHV-6A did not induce CD4 expression and had no influence on chemokine receptor expression. Activation of HIV-1 from latency in coinfected cells was mediated by the immediate-early (IE)-A and IE-B gene products of HHV-6A. Open reading frames U86 and U89 of the IE-A region were able to activate HIV-1 replication in a synergistic manner. The data suggest that in vivo double infection of syncytiotrophoblast cells with HHV-6A and HIV-1 could contribute to the transplacental transmission of HIV-1 but not HHV-6A.

Induction of HIV-1 replication in latently infected syncytiotrophoblast cells by contact with placental macrophages: role of interleukin-6 and tumor necrosis factor-alpha

The syncytiotrophoblast (ST) layer of the human placenta has an important role in limiting transplacental viral spread from mother to fetus. Although certain strains of human immunodeficiency virus type 1 (HIV-1) may enter ST cells, the trophoblast does not exhibit permissiveness for HIV-1. The present study tested the possibility that placental macrophages might induce replication of HIV-1 carried in ST cells and, further, that infected ST cells would be capable of transmitting virus into neighboring macrophages. For this purpose, we investigated HIV-1 replication in ST cells grown alone or cocultured with uninfected placental macrophages. The macrophage-tropic Ba-L strain of HIV-1, capable of entering ST cells, was used throughout our studies. We demonstrated that interactions between ST cells and macrophages activated HIV-1 from latency and induced its replication in ST cells. After having become permissive for viral replication, ST cells delivered HIV-1 to the cocultured macrophages, as evidenced by detection of virus-specific antigens in these cells. The stimulatory effect of coculture on HIV-1 gene expression in ST cells was mediated by marked tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) release from macrophages, an effect caused by contact between the different placental cells. Results of this study suggest an interactive role for the ST layer and placental macrophages in the dissemination of HIV-1 among placental tissue. Data reported here may also explain why macrophage-tropic HIV-1 strains are transmitted preferentially during pregnancy.

Pseudotypes of vesicular stomatitis virus-bearing envelope antigens of certain HIV-1 strains permissively infect human syncytiotrophoblasts cultured in vitro: implications for in vivo infection of syncytiotrophoblasts by cell-free HIV-1

Intrauterine infection of the fetus is clearly an important mode of vertical transmission of human immunodeficiency virus type 1 (HIV-1). The syncytiotrophoblast layer of the human placenta must be traversed by HIV-1 in order to reach underlying cells and fetal capillaries. Although HIV-1 has been detected in the syncytiotrophoblast layer in situ, there is conflicting evidence regarding infection of syncytiotrophoblast cells with cell-free virus. The phenotypic mixing between HIV-1 and vesicular stomatitis virus (VSV) has been exploited to assay the susceptibility of human term syncytiotrophoblast cells to penetration by various strains of HIV-1. VSV(HIV-1(IIIB)) and VSV(HIV-1(Ba-L)) pseudotypes were found to enter syncytiotrophoblast cells. In contrast, VSV pseudotyped with envelope glycoproteins of RF, MN, or Ada-M strains of HIV-1 did not infect syncytiotrophoblasts. Plating efficiency of VSV(HIV-1(IIIB)) and VSV(HIV-1(Ba-L)) was 10-fold lower on syncytiotrophoblasts than on T-cells and macrophages, respectively. Incubation of VSV(HIV-1(IIIB)) and VSV(HIV-1(Ba-L)) viruses with appropriate HIV-1 neutralizing sera before infection strongly inhibited entry of pseudotyped VSV into syncytiotrophoblast cells. These findings demonstrated that infection of syncytiotrophoblasts with VSV(HIV-1) pseudotypes was mediated by Env from IIIB and Ba-L strains of HIV-1. Monoclonal antibodies (MAb) to CD4, CXCR4, CCR5, and CCR3 were tested for their ability to block VSV(HIV-1) infection of syncytiotrophoblast cells. Neither the anti-CD4 nor the anti-CXCR4, anti-CCR5, and anti-CCR3 MAb had any inhibitory effect on infection of syncytiotrophoblast cells with VSV(HIV-1) pseudotypes. Results from this study suggest that cell-free HIV-1 can enter syncytiotrophoblasts and the susceptibility of these cells to penetration by the virus is strain dependent. Pseudotype infection merely demonstrates that the first steps in HIV-1 replication are possible in syncytiotrophoblast cells.

Predominance of genotype A HBV in an HBV-HIV-1 dually positive population compared with an HIV-1-negative counterpart in Japan

Hepatitis B virus (HBV) has seven genotypes, A to G. Previous studies have shown that genotype C is the most prevalent strain in chronic HBV carriers in East Asia. This study was undertaken to investigate the epidemiology of HBV genotypes among Japanese patients who are coinfected with human immunodeficiency virus type 1 (HIV-1). The sequences of the complete hepatitis B surface antifen (HBsAg) genes were obtained from 18 coinfected Japanese patients. Among the 18 patients, 12 of 13 men who had sex with men (MSM) had genotype A (92%), whereas only one of five heterosexual or hemophiliac patients had genotype A. The predominance of genotype A HBV in MSM showed a striking contrast to the current genotype prevalence in the Japanese population. Owing to the recent decrease in the rate of vertical transmission in Japan, the role of sexual behavior in the transmission of HBV cannot be overestimated. Thus, the relative proportion of genotype A may gradually increase in Japan.

Correlation of virus load and soluble L-selectin, a marker of immune activation, in pediatric HIV-1 infection

OBJECTIVE

HIV infections in children are characterized by high viral load and, in some perinatally infected newborns, delayed appearance of viral markers. Both phenomena may be related to different levels of immune activation affecting viral replication. This study was designed to investigate the relationship between immune activation and viral replication in pediatric HIV infection, and the role of pre-existent immune activation in facilitating HIV transmission to the fetus/newborn.

DESIGN

Plasma levels of soluble L-selectin (s-LS), an immune activation marker, were determined in 100 infants with perinatally transmitted HIV infection, compared with 106 age-matched HIV-exposed uninfected controls. Included in the analysis were samples from 31 HIV-infected (10 PCR+ and 21 PCR-) and 35 uninfected newborns aged < 2 days.

METHODS

To determine s-LS levels, a solid phase ELISA was performed on plasma samples of patients and controls.

RESULTS

s-LS levels in uninfected children were higher than those in normal adults. HIV-infected patients had more rapidly increasing values in the first 6 months of life compared with uninfected infants. Plasma s-LS levels correlated with HIV viral loads (r, 0.50). Among newborns in the first 2 days of life, s-LS levels were lowest in those with negative PCR tests, compared with PCR-positive or uninfected infants.

CONCLUSIONS

These results suggest that higher immune activation in children contributes to higher viral loads, and that the level of pre-existent immune activation may have a role in determining which infants have detectable virus in peripheral blood at birth.

Early diagnosis of HIV-1-infected infants in Thailand using RNA and DNA PCR assays sensitive to non-B subtypes

OBJECTIVES

To evaluate the sensitivity and specificity of RNA and DNA polymerase chain reaction (PCR) for early diagnosis of perinatal HIV-1 infection and to investigate early viral dynamics in infected infants.

DESIGN

A cohort study of 395 non-breastfed infants born to HIV-infected mothers in a randomized clinical trial of short-course antenatal zidovudine.

METHODS

Infant venous blood specimens collected at birth, 2 months, and 6 months of age were tested by qualitative DNA and quantitative RNA PCR (Roche Amplicor). To determine sensitivity and specificity of DNA and RNA PCR, results were compared with later DNA PCR results and to antibody results at 18 months. The HIV-1 subtype of the mother's infection was determined by peptide serotyping.

RESULTS

In the study, 92% of mothers were infected with subtype E. DNA PCR sensitivity was 38% (20 of 53) at birth, and 100% at 2 months (53 of 53) and 6 months (47 of 47). RNA PCR sensitivity was 47% (25 of 53) at birth and 100% (53 of 53) at 2 months. All samples that tested DNA-positive tested RNA-positive. Specificity was 100% for both DNA and RNA testing at all timepoints. For infected infants, the median viral load of RNA-positive specimens was 407,000 copies/ml (5.6 log10) at birth, 3, 700,000 copies/ml (6.6 log10) at 2 months, and 1,700,000 copies/ml (6.2 log10) at 6 months. Infant RNA levels at 2 and 6 months did not differ by maternal zidovudine exposure, or RNA level at birth.

CONCLUSION

This RNA PCR assay performed well for diagnosing perinatal HIV subtype E infection, detecting nearly half of infected infants at birth, and 100% at 2 and 6 months, with 100% specificity. Infected infant viral RNA levels were very high at 2 and 6 months, and were unaffected by maternal zidovudine treatment.

Kinetic analysis of microchimerism induced by intrathymic injection of allogeneic splenocytes in mice

Allograft survival facilitated by intrathymic (i.t.) injection of allogeneic cells have shown that modifications of T-cell development induce specific tolerance. One hypothesis is that the resulting microchimerism may play a role in preparing the host immune system for the allograft. To investigate whether the deliberate introduction of allogeneic splenocytes into the thymus of adult mice allows the establishment of a lasting donor/recipient microchimerism, a full allogeneic mouse system (H-2 and Mls) with additional sex mismatch was used. Male cells injected into female mice were detected using an optimized nested-polymerase chain reaction which specifically amplifies the SRY gene with a sensitivity of 1/10(4). After i.t. injection, donor cells were observed early both in the lymph nodes and spleen (75 and 25% of mice, respectively). They were still present on day 6, although preferentially in the thymus (100% of mice) than in the lymph nodes (50% of mice) or in the spleen (22% of mice). After intraperitoneal (i.p.) or subcutaneous (s.c.) injection, donor cells were early (2 h) but transiently detected in the thymus, since on day 6 they were detected in 0 and 17% of mice after i.p. and s.c. injection, respectively. Kinetics of donor-cell detection was similar both in the spleen and lymph nodes with a clear decrease in the percentage of mice with donor-cell detection between day 2 and day 6 (20 and 17% of positive mice for the spleen after i.p. and s.c. injections, respectively--20 and 33% of positive mice for the lymph nodes after i.p. and s.c. injections, respectively). Our results clearly show that i.t. injection of allogeneic splenocytes induces a microchimerism which is both more lasting and detected in a higher percentage of mice than by the i.p. and s.c. routes, both at the central (thymus) and peripheral (spleen) levels.

Diagnosis of HIV infection in children

Many advances have been made in the area of HIV diagnostics. Commercially available virologic assays are sensitive and specific for the early detection of HIV in perinatal infection. The timing of the transmission of HIV from mother to child (in utero, at the time of birth, or postnatally by breast-feeding) is a critical consideration in the appropriate diagnosis of infants. Several algorithms can be used to define early infection and the potential timing of acquisition of infection that combine different assays and timing of specimens. The use of virologic assays, including HIV DNA PCR and HIV RNA detection methods and culture, can define and rule out infection in infants less than 18 months of age. Serologic diagnostic methods, including HIV ELISA, immunofluorescence, and western blot assays, can be used to diagnose infants more than 18 months of age, when transplacental antibody has disappeared in uninfected HIV-exposed infants. The challenge of the early and accurate diagnosis of perinatally HIV-exposed infants is the use of new assays to detect different HIV subtype infections that are prevalent in developing countries. Rapid, simple, and inexpensive serologic and virologic assays are being developed for worldwide use.

Molecular epidemiology of HIV-1 in Switzerland: evidence for a silent mutation in the C2V3 region distinguishing intravenous drug users from homosexual men. Swiss HIV Cohort Study

OBJECTIVES

To study the molecular epidemiology of HIV-1 strains found in Switzerland and to determine possible genetic linkages among strains sorted by risk group or geographic region.

DESIGN

A cross-sectional, clinic-based survey of HIV-1 molecular sequences and linked patient history from Swiss people.

METHODS

Specimens were collected from 215 HIV-1-infected people in HIV outpatient clinics of four tertiary referral centers (Lausanne, St. Gallen, Zurich, and Basel) between May and August 1996, mainly from homosexual men, injecting drug users (IDU), and heterosexually infected people. In addition, specimens collected between 1991 and 1995 in the HIV outpatient clinic at University of Geneva were included into this survey. These specimens were collected primarily for an ongoing, prospective cohort (Swiss HIV Cohort Study). Direct C2V3C3 sequences of the env gene were determined from 158 samples of peripheral blood mononuclear cells. Genetic data were analyzed with the available patient history on each specimen.

RESULTS

As found in other previous studies in Europe, primarily subtype B viruses were identified, whereas seven (4%) of 158 were non-subtype B: one subtype D, four subtype A, and two subtype E. Five of seven non-B subtypes occurred in immigrants from African or Asian countries and all seven were found exclusively in individuals who had been infected by heterosexual contact. No significant clustering of strains within different study sites or risk groups was found. A silent mutation (LAI env 834) occurred significantly more often in IDU than in homosexual men (p<.001).

CONCLUSIONS

Although the lack of significant clustering of strains by risk group or geographic region may result from early introduction of subtype B viruses in Switzerland, the strong association of a silent mutation with IDU suggests that, early in the epidemic, there was a unique founder virus among IDUs. The HIV epidemic in Switzerland is still predominantly caused by subtype B viruses.

Evaluation of the prototype Roche DNA amplification kit incorporating the new SSK145 and SKCC1B primers in detection of human immunodeficiency virus type 1 DNA in Zimbabwe

We assessed the sensitivity and specificity of a newly developed DNA PCR kit (Roche Diagnostic Corporation, Indianapolis, Ind.) that incorporates primers for all the group M viruses for the detection of human immunodeficiency virus (HIV) type 1 (HIV-1) infection in Zimbabwe. A total of 202 whole-blood samples from adults whose HIV status was known were studied. This included 100 HIV-1-positive and 102 HIV-1-negative samples selected on the basis of concordant results obtained with two enzyme-linked immunosorbent assay kits. The prototype Roche DNA PCR assay had a 100% sensitivity for the detection of HIV-1 DNA and a specificity of 100%. We conclude that the new Roche DNA PCR kit is accurate for the detection of HIV DNA in Zimbabwean samples, in which HIV-1 subtype C dominates.

Maternal syphilis and vertical perinatal transmission of human immunodeficiency virus type-1 infection

OBJECTIVES

To identify risk factors for vertical HIV transmission that may provide opportunities for the prevention of future pediatric HIV infection.

STUDY DESIGN

A prospective cohort of 44 pregnant HIV(+) women and their 53 offspring was followed between July 1989 and July 1996.

RESULTS

Secondary and latent maternal syphilis infection was diagnosed in four pregnancies with VDRL titers > or = 1:128. Concurrent maternal syphilis infection was associated with 100% vertical HIV transmission (4/4), compared to 21% (3/14) deliveries that occurred in 13 women with only a history of treated sypillis (P = 0.01) and 14% (5/35) deliveries in women with no history of syphilis (P = 0.0015). Among non-Zidovudine exposed pregnancies, 100% (3/3) patients with concurrent syphilis transmitted HIV to their infants vs. 0% (0/8) patients with only a history of syphilis (P = 0.006). A history of treated syphilis did not increase subsequent transmission risk compared to women with no history of syphilis (3/14 vs. 5/35, P = 0.41). One patient delivered twice during the study and received Zidovudine prophylaxis during both pregnancies. Her first pregnancy VDRL titer was > or = 1:128, during which she delivered an HIV infected child. Following successful treatment for syphilis (VDRL titer, 1:1), she conceived again and delivered an uninfected infant 11 months later. Additional risk factors significantly associated with vertical HIV transmission were prematurity and low birth weight. Variables studied but not statistically-related to HIV transmission included: other sexually transmitted diseases, maternal age, race, intravenous drug or cocaine use, prenatal care, route of delivery, duration of HIV(+) status, and CD4 count.

CONCLUSION

Among HIV(+) women, concurrent syphilis infection, but not a history of syphilis, is significantly associated with vertical perinatal HIV transmission. Frequent screening and prompt treatment of syphilis in non-pregnant HIV(+) women may help prevent subsequent HIV infected pregnancies.

Incubation period of HIV-1 in perinatally infected children. New York City Perinatal HIV Transmission Collaborative Study Group

OBJECTIVES

To estimate the distribution of the incubation period of HIV-1 among perinatally infected children and to test the hypothesis that this distribution has been changing over time.

DESIGN

An analysis of 190 perinatally HIV-1-infected children born between 1986 and 1997 in eight medical centers in New York City to women enrolled in a prospective cohort study.

METHODS

Non-parametric Kaplan-Meier method and parametric survival analysis.

RESULTS

Using the Kaplan-Meier method it was estimated that among perinatally HIV-1-infected children, 48% [95% confidence interval (CI), 41-56] developed AIDS by 3 years of age after which the rate was less than 3% per year. Using a parametric survival analysis for extrapolation, it was predicted that 33% (95% CI, 23-43) would remain AIDS-free at 13 years of age. Median age at onset of AIDS was estimated to be 4.1 years (95% CI, 1.9-6.4) by parametric survival analysis. The year of birth was significantly associated with AIDS-free survival, suggesting an increase in the time to AIDS over the years. This association remained significant (P=0.03) after adjustment for those maternal characteristics that have also changed over time: timing of enrollment (prepartum versus postpartum), zidovudine, alcohol, and hard drug (heroin, cocaine or methadone) use during pregnancy.

CONCLUSIONS

Although a substantial proportion of perinatally HIV-1-infected children develop AIDS very early in life, a significant and increasing percentage of them are expected to survive into adolescence without developing AIDS. Further research is needed to determine the factors associated with the lengthening survival to AIDS.

Medical management of the pregnant woman infected with human immunodeficiency virus type 1 and her child

Heterosexual contact and intravenous drug use continue to result in new cases of human immunodeficiency virus type 1 (HIV-1) infection among adolescents and women of childbearing age. In North American and European surveys, 0.1% to 0.3% of childbearing women are infected with HIV; rates are 10 to 20 times higher in some inner-city areas. Timely, comprehensive, and well-coordinated care of the pregnant HIV-infected mother offers a unique opportunity to significantly influence two lives simultaneously. The mother can be offered therapeutic and prophylactic agents to treat her own infection, including antiretroviral therapy, which has been shown to markedly reduce the risk of vertical HIV-1 transmission. Recent advances in diagnostic virology now make it possible to definitively identify by 3 to 4 months of age those infants who are infected with HIV. Infants infected with HIV can be offered effective prophylaxis against Pneumocystis carinii pneumonia, which has dramatically reduced the incidence of this once common infection. Infected infants also should be monitored closely to institute antiretroviral therapy, and to diagnose and treat opportunistic and intercurrent infections and other acquired immunodeficiency syndrome-defining illnesses in a timely way.

Perinatal transmission of HIV and diagnosis of HIV infection in infants: a review

Paediatric HIV infection has become a major burden on families, communities and health services worldwide. The vast majority of children now acquire HIV as a result of mother to infant (vertical) transmission. Recent major advances have occurred following the greater understanding of the risk factors for perinatal transmission and the role of antiretroviral therapy in preventing transmission. Now that interruption of vertical transmission is possible, early identification of HIV-infected pregnant women is critical. As of June 1997, HIV infection has been diagnosed in 37 children under 15 yrs of age in the Republic of Ireland; 32 as a result of maternal to infant transmission. The exact timing of HIV transmission during pregnancy is unclear but it is estimated that 60-70 per cent of infants may be infected at the time of delivery with approximately 30 per cent infected earlier in gestation. Vertical transmission rates vary from 15-40 per cent in different global areas. Antenatal and perinatal zidovudine treatment can reduce this rate by 60-70 per cent. Risk factors for the vertical transmission of HIV-1 are multifactorial. These factors include maternal disease status, in particular maternal viral load, route of delivery, duration of membrane rupture, presence of obstetric complications and infant feeding practices. Definitive diagnosis of HIV infection in infancy has been difficult in the past. Direct viral detection methods now allow the reliable diagnosis of HIV infection in the first few months of life. The most effective intervention to reduce perinatal HIV infection will be the better identification of HIV positive pregnant women with the subsequent introduction of measures to interrupt vertical transmission of HIV.

Early diagnosis of vertical HIV infection in infants by rapid detection of immune complex-dissociated HIV p24 antigen

Conventional HIV antibody detection was problematic for diagnosis of HIV infection in young infants < 18 months of age who were born to HIV-infected mothers. The HIV p24 antigen (Ag) is mainly bound to the antibody as an immune complex which causes underdetection by conventional methods. Attempts were made to dissociate these immune complexes to release free p24 Ag for detection. The current study's objective was to evaluate the rapid assays for detection of immune complex-dissociated p24 Ag (ICD p24 Ag) for early identification of HIV-infected infants as compared to the detection of HIV RNA by polymerase chain reaction (PCR) assay. The ICD was performed by acid dissociation and heat-denatured dissociation, and then the released ICD p24 Ag were detected. Tested were 41 HIV-infected children who acquired the infection perinatally and who had positive PCR and 30 HIV noninfected children with negative PCR. The overall sensitivity of the ICD p24 Ag detection after acid- and heat-denatured dissociation in the infected children was 85.4% and 87.8%, respectively, compared to 34.2% of p24 Ag without pretreatment for dissociation of the serum samples. The specificity of nonimmune complex dissociation and both methods of immune complex dissociation test were 100%. The sensitivity of ICD-p24 Ag test using these two methods showed excellent agreement (K = 0.893). Besides the relatively high sensitivity and specificity of the ICD p24 Ag test, its advantages include simplicity, rapidity, and relatively low cost--indicating ICD p24 Ag detection as a promising method for early diagnosis of vertical HIV infection in infants.

A multicentre quality assessment study to monitor the performance of HIV-1 PCR

Eleven German laboratories and one Swiss laboratory initiated a quality assessment study to evaluate the specificity and sensitivity of their polymerase chain reaction (PCR) for detection of HIV-1 DNA. Following its own PCR protocols, each laboratory tested a panel of ten coded samples consisting of cell pellets containing 0, 0.1, 1, 10, 10(2), 10(3) and 10(4) ACH-2 cells per 1.5 x 10(5) uninfected peripheral blood mononuclear cells. Of the twelve participating laboratories, three reported correct results for the dilution series as well as for uninfected specimens. One or more classification errors were recorded for 12% of the samples for which the diagnosis was expected to be positive or negative. Samples containing 10 copies of the target template were correctly reported by eleven of the twelve participants. The average sensitivity was 97%. The results of the study revealed no significant differences between the Amplicor kit and in-house procedures. Most of the classification errors occurred in specimens from HIV-negative samples. Out of 36 negative samples, 5 were reported false positive, showing that contamination remains a problem for some laboratories, regardless of the PCR test performed. Careful laboratory techniques and internal as well as external quality control procedures will help avoiding carryover contamination.

Maternal clinical factors influencing HIV-1 transmission

The complex puzzle of maternal factors involved in mother-to-child human immunodeficiency virus type 1 (HIV-1) transmission is being put together. The risk of perinatal infection increases with mother's disease progression, but it remains stable in women seroconverting to HIV-1 during pregnancy and in consecutive pregnancies. Thus, transmission correlates with the HIV-1 progression rather than the duration of infection in the mother. Nutritional alterations such as vitamin A deficiency may also have a significant impact, whereas geographic origin and mode of maternal infection are of no influence. Placenta membrane inflammation and concurrent sexually transmitted diseases are other significant covariates. The rate of transmission appears directly correlated with maternal age and inversely with length of gestation. A protective effect of caesarean section has been reported in some observational studies but, being controversial, these results need to be corroborated by randomized trials.

Inflammatory cytokine expression is correlated with the level of human immunodeficiency virus (HIV) transcripts in HIV-infected placental trophoblastic cells

The inflammatory cytokines interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor alpha (TNF-alpha) have been associated with increased human immunodeficiency virus (HIV) expression and enhanced lymphocyte adhesion to trophoblastic cells in experimental systems. To determine if there is a correlation between the expression of these cytokines and the levels of HIV transcripts in trophoblasts of term placentas from HIV-infected women, we studied the placentae of 30 HIV-positive and 13 control gravidae. Twenty-three of the HIV-positive women received zidovudine (ZDV) as prophylaxis against HIV vertical transmission; only one of the seven women who did not receive ZDV was a transmitter, for an overall vertical transmission rate of 3.8%. Cytokine production was measured by enzyme-linked immunosorbent assay in the supernatants of trophoblastic cell cultures. Additionally, cytokine transcripts and HIV gag sequences were determined by a quantitative reverse transcription-PCR assay. In general, trophoblastic cells of HIV-positive placentas expressed significantly higher levels of IL-1beta, IL-6, and TNF-alpha than those of control placentas. All placentas from HIV-positive women expressed HIV gag transcripts at either a low (<156 copies per microg of total RNA) or a high (>156 copies per microg of total RNA) level. There was a statistically significant positive association between the basal level of TNF-alpha production and the level of HIV gag transcripts of HIV-positive placental trophoblastic cells. Nevertheless, these data, coupled with a low transmission rate, would indicate that some other factors, perhaps working in concert with cytokines, are necessary for vertical transmission of HIV from mother to infant.

Transmission of HIV-1 in infants born to seropositive mothers: PCR-amplified proviral DNA detected by flow cytometric analysis of immunoreactive beads

The diagnosis of HIV infection in newborns is established by amplification of proviral DNA using the polymerase chain reaction (PCR). We developed a nonisotopic method for heminested PCR using a biotinylated primer among sets of three oligonucleotides, each selected from the HIV long terminal repeat (LTR) and gag sequences. An internal probe incorporating digoxigenin-dUTP was also synthesized by PCR. The PCR products, hybridized with LTR region or gag region probes, were captured with streptavidin-coated magnetic beads and detected by fluorescein isothiocyanate-labeled antidigoxigenin in flow cytometric analysis. This immunoreactive bead assay (PCR-IRB) detected about three copies of HIV proviral DNA. A panel of 50 coded DNA specimens of infants previously assayed by conventional PCR and with known clinical results revealed that the PCR-IRB findings using LTR, but not gag, were in agreement. A double-blind prospective study of blood samples from 14 mother-infant pairs using the PCR-IRB amplification of LTR gave results similar to the commercial Amplicor HIV-1 PCR test and were consistent with the clinical outcomes. PCR-IRB results were positive for 11 mothers and three infants, one at birth, one at 2 weeks after birth, and one at 8 weeks after birth. PCR-IRB is a simple, reliable, specific, and automatable assay useful in the early diagnosis of perinatal HIV infection in clinical practice and regional screening programs.

Morbidity and mortality in European children vertically infected by HIV-1. The French Pediatric HIV Infection Study Group and European Collaborative Study

Based on 392 infected children enrolled in two European prospective studies of infants born to HIV-infected women, with similar standard protocols, HIV disease progression in the first 6 years of life is described, using the 1994 CDC paediatric HIV classification. Most children had developed minor (A) or moderately severe (B) illness in the first 4 years of life, although usually it was transient in nature. Progression to U.S. Centers for Disease Control and Prevention (CDC) group C disease or HIV-related death is an estimated 20% (95% confidence interval 16-24%) during the first year of life, and 4.7% (3.3-6.5%) per year thereafter, giving a cumulative incidence of 36% (30-43%) by 6 years. The mortality rate at 6 years is 26% (20-32%). Two thirds of the children alive at 6 years had only minor symptoms, and one third had a CD4+ cell distribution of > 25% despite previous clinical manifestations and a transient period of moderate immune deficiency. Differences in zidovudine monotherapy between the two cohorts were not associated with the mortality rate. However, the risk of severe bacterial infections was lower in the French cohort, in which the use of antibacterial prophylaxis was more common. The early, severe form of HIV disease affects approximately 20% of infants, and after 6 years 75% of infected children are still alive. This has important implications for health-care planning.

Fertility and reproductive choice in women with HIV-1 infection

OBJECTIVE

To measure fertility and birth rates and to describe the reproductive histories of women diagnosed with HIV-1 infection in Australia.

METHODS

The medical records of 294 women with HIV-1 infection in four states of Australia were reviewed. Expected fertility and birth rates were calculated using national statistics.

RESULTS

In the study population, 152 (52%) women had at least one pregnancy prior or subsequent to HIV-1 diagnosis. At maternal HIV-1 diagnosis, 71 (24%) women had a total of 106 children aged under 15 years. During the study period, 246 women were aged 15, 44 years and 58 (23%) of these became pregnant after HIV-1 diagnosis. Women whose exposure to HIV-1 was injecting drug use were twice as likely to become pregnant and more likely to have multiple pregnancies than women who did not report injecting drug use. The annual general fertility rate was 30 per 10,000 compared with 63 per 10,000 for the Australian female population aged 15-44 years, and the birth rate in women with HIV-1 infection was one-half that of the general female population. Of pregnancies confirmed after HIV-1 diagnosis, 47% were voluntarily terminated, a rate more than double that of the general population. All multiple terminations were among women whose exposure to HIV-1 was injecting drug use.

CONCLUSIONS

Fertility and birth rates among women with HIV-1 infection are lower than the general population and the rate of termination higher. The results of this study provide a basis for the management of women with HIV-1 infection who are considering pregnancy.

The effect of maternal viral load on the risk of perinatal transmission of HIV-1. New York City Perinatal HIV Transmission Collaborative Study Group

OBJECTIVE

To determine the effect of maternal viral load at delivery on the risk of perinatal transmission of HIV-1.

DESIGN

A nested case-control study within a prospectively followed cohort of HIV-1-infected pregnant women and their infants.

SETTING

The multicenter New York City Perinatal HIV Transmission Collaborative Study.

PARTICIPANTS

Fifty-one women who gave birth to HIV-1 infected infants were frequency-matched within CD4+ cell count quintiles with 54 non-transmitting mothers.

MAIN OUTCOME MEASURES

Maternal quantity of HIV-1 viral RNA was assayed in plasma obtained near delivery using the nucleic acid sequence-based amplification assay system.

RESULTS

Viral RNA was detected in 73 (70%) out of 105 women and the median viral load was 16,000 RNA copies/ml in transmitters and 6,600 in non-transmitters (P < 0.01). When adjusted for maternal CD4+ count near delivery, women with measurable viral load were nearly sixfold more likely to transmit HIV-1 than women with viral load below detection [adjusted odds ratio (AOR), 5.8; 95% confidence interval (CI), 2.2 15.5]. The odds ratio for perinatal transmission of log10 viral load, adjusted for CD4 count was 2.7 (95% CI, 1.5-5.1). When stratified by the stage of HIV-1 disease, the only group with significant association between log10 viral load and transmission were AIDS-free women with CD4+ count > 500 x 10(6)/l (AOR, 9.1; 95% CI, 2.6-31.5).

CONCLUSIONS

High maternal viral load increases the likelihood of perinatal transmission of HIV-1 in women without AIDS and advanced immunosuppression. HIV-1 infected pregnant women without advanced disease, shown by others to have the lowest risk of perinatal transmission, may benefit the most from efforts to identify and decrease viral load at delivery.

Timing of maternal-infant HIV transmission: associations between intrapartum factors and early polymerase chain reaction results. New York City Perinatal HIV Transmission Collaborative Study Group

OBJECTIVE

To investigate the hypothesis that labour and delivery events, perinatal characteristics, and maternal factors are only associated with intrapartum HIV transmission, and not with intrauterine HIV transmission.

METHODS

In the New York City Perinatal HIV Transmission Collaborative Study 276 infants of HIV-infected women were followed prospectively and had results of early polymerase chain reaction (PCR) tests available. Among infected children, intrauterine infection was presumed if HIV DNA was detected by PCR in samples collected from children aged < or = 3 days, and intrapartum infection was presumed if HIV DNA was not detected in these early samples. The proportion of infants with presumed intrauterine and intrapartum infections were compared by selected intrapartum, perinatal and maternal characteristics.

RESULTS

Presumed intrapartum infection was found in 7% of infants delivered by Cesarean section and, among infants delivered vaginally, those with longer duration of membrane rupture (> 4 h) were significantly more likely to have presumed intrapartum HIV infection (22%) than those with shorter duration (9%; P = 0.02). There were no differences in presumed intrauterine HIV infection by mode of delivery or longer duration of membrane rupture. Infants born preterm and small for gestational age had significantly higher risks of presumed intrapartum infection, but only those who were small for gestational age had higher risks of intrauterine infection.

CONCLUSION

Our results support the notion that selected intrapartum conditions, long duration of membrane rupture prior to delivery in particular, are independent risk factors for maternal-infant transmission, and suggest that preterm infants may be especially vulnerable to intrapartum HIV exposure.

Vitamin A deficiency and maternal-infant transmissions of HIV in two metropolitan areas in the United States

OBJECTIVE

To determine whether vitamin A deficiency is associated with maternal-infant HIV transmission among HIV-infected pregnant women in two United States cities.

METHODS

Third trimester serum vitamin A levels were evaluated using high-performance liquid chromatography in 133 HIV-infected women who delivered livebirths during May 1986 to May 1994 and whose infants had known HIV infection status.

RESULTS

Sixteen per cent (seven out of 44) of the transmitting mothers and 6% (five out of 89) of the non-transmitting mothers had severe vitamin A deficiency (< 0.70 mumol/l; P = 0.05). Maternal-infant transmission was also associated with prematurity < 37 weeks gestation (P = 0.02), and Cesarean section delivery (P = 0.04), CD4 percentage (P = 0.03) and marginally associated with duration of membrane rupture of > or = 4 h (P = 0.06) by univariate analysis. In a multivariate logistic regression model, severe vitamin A deficiency [adjusted odds ratio (AOR), 5.05; 95% confidence interval (CI), 1.20-21.24], Cesarean section delivery (AOR, 3.75; 95% CI, 1.10-12.87), and prematurity (AOR, 2.25; 95% CI, 1.22-4.13) were associated with transmission after adjusting for CD4+ percentage, and duration of membrane rupture.

CONCLUSION

Increased risk of maternal-infant transmission was associated with severe vitamin A deficiency among non-breastfeeding women in these cohorts from the United States.

Plasma viremia and virus phenotype are correlates of disease progression in vertically human immunodeficiency virus type 1-infected children

OBJECTIVE

To analyze the relationships among HIV-1 plasma viremia, phenotype and CD4 T cell counts in vertically infected children.

METHODS

Plasma viremia was quantified in 37 vertically infected children at different stages of the disease by a standardized molecular assay. Virus isolation and non-syncytia-inducing or syncytia-inducing (SI) HIV-1 phenotype evaluation were performed in parallel.

RESULTS

HIV-1 RNA genomes were found to be significantly different in CDC clinical classes N, A, B and C (P = 0.0135) and in immunologic classes 1, 2 and 3 (P = 0.0110). None of the children in Class N or A harbored HIV-1 isolates with SI phenotype, whereas SI primary isolates were detected in 2 of 7 (29%) and 7 of 10 (70%) Class B and C children, respectively. Similarly SI variants were present in only 9 of 13 children in immunologic Class 3 (70%). When stratified according to the increasing severity of virologic status, the children showed a significant difference (P = 0.0458) in viral burden.

CONCLUSIONS

Clinical symptoms, the most dramatic being reduction in the number of CD4 lymphocytes, and the highest plasma viremia levels were observed in the children in whom fast replicating, highly cytopathic SI variants were isolated. These data extend the virologic characterization of vertically HIV-1 infected children and suggest that both the plasma viremia levels and phenotype of primary isolates are viral correlates of disease progression in vertically infected children.