Effectiveness of Short-Term and Long-Term Zidovudine Prophylaxis on Detection of HIV-1 Subtype E in Human Placenta and Vertical Transmission

Relationship of cell bearing EBER and p24 antigens in biopsy-proven lymphocytic interstitial pneumonia in HIV-1 subtype E infected children

Lymphocytic interstitial pneumonia (LIP) is an uncommon histopathologic entity characterized by infiltration of the interstitium and alveolar spaces of the lung by lymphocytes and other lymphoid elements. An increased incidence of LIP has been seen in the pediatric population, especially in children with acquired immune deficiency syndrome. Our previous study supports the notion that Langerhans cells (LCs) are reservoirs for Epstein-Barr virus (EBV) in lungs of human immunodeficiency virus (HIV) subtype E-infected pediatric LIP. To further understand the pathogenesis of LIP, we studied the relationship between EBV, the suggested causative agent of LIP and HIV-1 capsid protein p24, which play an important role in the interaction with host proteins during HIV-1 adsorption, membrane fusion, and entry in surgical lung biopsy-proven LIP from 9 vertically HIV subtype E-infected pediatric patients. The dominant microscopic feature of LIP demonstrated widespread widening of alveolar septum by mononuclear inflammatory cell infiltrate, mainly composed of mature lymphocytes and plasma cells surrounding airways and expanding to the lung interstitium. EBV-encoded RNA (EBER) in situ hybridization (ISH) and p24 immunohistochemistry, performed on formalin-fixed, paraffin-embedded tissue from open lung biopsy specimens, revealed positive intranuclear EBER signals and intracytoplasmic immunostains for p24 core protein in all 9 LIP cases. By combining ISH and immunohistochemistry, these results suggest that (i) EBV/p24-carrying cells are likely involved in the development of LIP, either directly or indirectly; (ii) LCs and related dendritic cells are the main reservoir of both EBV and HIV subtype E in pediatric LIP and possibly LCs may play an important role in the recruitment of inflammatory cell infiltrates, especially T cells into these tissues; (iii) coexpression of EBV/p24 in bronchioalveolar epithelium supports the hypothesis that these cells serve as a reactivation source for both viruses to achieve greater quantities in alveolar septum and interstitium around bronchioles. These results indicate a strong association between the presence of HIV core protein p24 and expression of EBV RNA transcripts (EBER). Interactions between LCs and related dendritic cells together with T cells are important for effective HIV and EBV replications. The coexpression of both viruses could be related to the evolution of pediatric LIP in HIV subtype E infection.

Human immunodeficiency virus type 1 mother-to-child transmission and prevention: successes and controversies

The World Health Organization (WHO) and United Nations Programme on HIV/AIDS (UNAIDS) estimated that an additional 370 000 new human immunodeficiency virus type 1 (HIV-1) infections occurred in children in 2009, mainly through mother-to-child transmission (MTCT). Intrapartum transmission contributes to approximately 20-25% of infections, in utero transmission to 5-10% and postnatal transmission to an additional 10-15% of cases. MTCT accounts for only a few hundred infected newborns in those countries in which services are established for voluntary counselling and testing of pregnant women, and a supply of antiretroviral drugs is available throughout pregnancy with recommendations for elective Caesarean section and avoidance of breastfeeding. The single-dose nevirapine regimen has provided the momentum to initiate MTCT programmes in many resource-limited countries; however, regimens using a combination of antiretroviral drugs are needed also to effectively reduce transmission via breastfeeding.

Antiretrovirals for reducing the risk of mother-to-child transmission of HIV infection

BACKGROUND

Antiretroviral drugs reduce viral replication and can reduce mother-to-child transmission of HIV either by lowering plasma viral load in pregnant women or through post-exposure prophylaxis in their newborns. In rich countries, highly active antiretroviral therapy (HAART) which usually comprises three drugs, has reduced the mother-to-child transmission rates to around 1-2%, but HAART is not always available in low- and middle-income countries. In these countries, various simpler and less costly antiretroviral regimens have been offered to pregnant women or to their newborn babies, or to both.

OBJECTIVES

To determine whether, and to what extent, antiretroviral regimens aimed at decreasing the risk of mother-to-child transmission of HIV infection achieve a clinically useful decrease in transmission risk, and what effect these interventions have on maternal and infant mortality and morbidity.

SEARCH STRATEGY

We sought to identify all relevant studies regardless of language or publication status by searching the Cochrane HIV/AIDS Review Group Trials Register, The Cochrane Library, MEDLINE, EMBASE and AIDSearch and relevant conference abstracts. We also contacted research organizations and experts in the field for unpublished and ongoing studies. The original review search strategy was conducted in 2002 and updated in 2006 and again in 2009.

SELECTION CRITERIA

Randomised controlled trials of any antiretroviral regimen aimed at decreasing the risk of mother-to-child transmission of HIV infection compared with placebo or no treatment, or compared with another antiretroviral regimen.

DATA COLLECTION AND ANALYSIS

Two authors independently selected relevant studies, extracted data and assessed trial quality. For the primary outcomes, we used survival analysis to estimate the probability of infants being infected with HIV (the observed proportion) at various specific time-points and calculated efficacy at a specific time as the relative reduction in the proportion infected. Efficacy, at a specific time, is defined as the preventive fraction in the exposed group compared to the reference group, which is the relative reduction in the proportion infected: 1-(Re/Rf). For those studies where efficacy and hence confidence intervals were not calculated, we calculated the approximate confidence intervals for the efficacy using recommended methods. For analysis of results that are not based on survival analyses we present the relative risk for each trial outcome based on the number randomised. No meta-analysis was conducted as no trial assessed identical drug regimens.

MAIN RESULTS

Twenty-five trials including 18,901 participants with a median trial sample size of 627 ranging from 50 to 1,844 participants were included in this update. Twenty-two trials randomised mothers (18 pre-natally and four in labour) and followed up their infants, and three trials randomised infants. The first trial began in April 1991 and assessed zidovudine (ZDV) versus placebo and since then, the type, dosage and duration of drugs to be compared has been modified in each subsequent trial. We present the results stratified by regimen and type of feeding.Antiretrovirals versus placebo In breastfeeding populations, three trials found that:ZDV given to mothers from 36 to 38 weeks gestation, during labour and for 7 days after delivery significantly reduced HIV infection at 4-8 weeks (Efficacy 32.00%; 95% CI 1.50 to 62.50), 3 to 4 months (Efficacy 33.07%; 95% CI 5.57 to 60.57), 6 months (Efficacy 34.55%; 95% CI 9.05 to 60.05), 12 months (Efficacy 34.31%; 95% CI 9.30 to 59.32) and 18 months (Efficacy 29.74%; 95% CI 2.73 to 56.75).ZDV given to mothers from 36 weeks gestation and during labour significantly reduced HIV infection at 4 to 8 weeks (Efficacy 43.78%; 95% CI 8.78 to 78.78) and 3 to 4 months (Efficacy 36.95%; 95% CI 2.94 to 70.96) but not at birth.ZDV plus lamivudine (3TC) given to mothers from 36 weeks gestation, during labour and for 7 days after delivery and to babies for the first 7 days after birth (PETRA 'regimen A') significantly reduced HIV infection (Efficacy 62.75%; 95% CI 40.76 to 84.74) and a combined endpoint of HIV infection or death (Efficacy 62.75 [, ]61.00%; 95% CI 40.76 to 84.74) at 4 to 8 weeks but these effects were not sustained at 18 months.ZDV plus 3TC given to mothers from the start of labour until 7 days after delivery and to babies for the first 7 days after birth (PETRA 'regimen B') significantly reduced HIV infection (Efficacy 41.83%; 95% CI 12.82 to 70.84) and HIV infection or death at 4 to 8 weeks (Efficacy 35.91%; 95% CI 8.41 to 63.41) but the effects were not sustained at 18 months.ZDV plus 3TC given to mothers during labour only (PETRA 'regimen C') with no treatment to babies did not reduce the risk of HIV infection at either 4 to 8 weeks or 18 months.In non-breastfeeding populations, three trials found that:ZDV given to mothers from 14 to 34 weeks gestation and during labour and to babies for the first 6 weeks after birth significantly reduced HIV infection in babies at 18 months (Efficacy 66.22%; 95% CI 33.94 to 98.50).ZDV given to mothers from 36 weeks gestation and during labour with no treatment to babies ('Thai-CDC regimen') significantly reduced HIV infection at 4 to 8 weeks (Efficacy 50.26%; 95% CI 13.80 to 86.72) but not at birthZDV given to mothers from 38 weeks gestation and during labour with no treatment to babies did not influence HIV transmission at 6 months.Longer versus shorter regimens using the same antiretrovirals One trial in a breastfeeding population found that:ZDV given to mothers during labour and to their babies for the first 3 days after birth compared with ZDV given to mothers from 36 weeks and during labour (similar to 'Thai-CDC') resulted in HIV infection rates that were not significantly different at birth, 4-8 weeks, 3 to 4 months, 6 months and 12 months.Three trials in non-breastfeeding populations found that:ZDV given to mothers from 28 weeks gestation during labour and to infants for the first 3 days after birth compared with ZDV given to mothers from 35 weeks gestation through labour and to infants from birth to 6 weeks significantly reduced HIV infection rate at 6 months (Efficacy 45.35 %; 95% CI 1.39 to 89.31) but compared with the same regimen ZDV given to mothers from 28 weeks gestation through labour and to infants from birth to 6 weeks did not result in a statistically significant difference in HIV infection at 6 months. ZDV given to mothers from 35 weeks gestation during labour and to infants for the first 3 days after birth was considered ineffective for reducing transmission rates and this regimen was discontinued.An antenatal/intrapartum course of ZDV used for a median of 76 days compared with an antenatal/intrapartum ZDV regimen used for a median 28 days with no treatment to babies in either group did not result in HIV infection rates that were significantly different at birth and at 3 to 4 months.In a programme where mothers were routinely receiving ZDV in the third trimester of pregnancy and babies were receiving one week of ZDV therapy, a single dose of nevirapine (NVP) given to mothers in labour and to their babies soon after birth compared with a single dose of NVP given to mothers only resulted in HIV infection rates that were not significantly different at birth and 6 months. However the reduction in risk of HIV infection or death at 6 months was marginally significant (Efficacy 45.00%; 95% CI -4.00 to 94.00).Antiretroviral regimens using different drugs and durations of treatmentIn breastfeeding populations, three trials found that:A single dose of NVP given to mothers at the onset of labour plus a single dose of NVP given to their babies immediately after birth ('HIVNET 012 regimen') compared with ZDV given to mothers during labour and to their babies for a week after birth resulted in lower HIV infection rates at 4-8 weeks (Efficacy 41.00%; 95% CI 11.84 to 70.16), 3-4 months (Efficacy 38.91%; 95% CI 11.24 to 66.58), 12 months (Efficacy 35.98 [9.25, 62.71]36.00%; 95% CI 8.56 to 63.44) and 18 months (Efficacy 39.15%; 95% CI 13.81 to 64.49). In addition, the NVP regimen significantly reduced the risk of HIV infection or death at 4-8 weeks (Efficacy 41.74%; 95% CI 14.30 to 69.18), 3 to 4 months (Efficacy 40.00%; 95% CI 14.34 to 65.66), 12 months (Efficacy 32.17%; 95% CI 8.51 to 55.83) and 18 months (Efficacy 32.57 [9.93, 55.21]33.00%; 95% CI 9.93 to 55.21).The 'HIVNET 012 regimen' plus ZDV given to babies for 1 week after birth compared with the 'HIVNET 012 regimen' alone did not result in a statistically significant difference in HIV infection at 4 to 8 weeks.A single dose of NVP given to babies immediately after birth plus ZDV given to babies for 1 week after birth compared with a single dose of NVP given to babies only significantly reduced the HIV infection rate at 4 to 8 weeks (Efficacy 36.79%; 95% CI 3.57 to 70.01).Five trials in non-breastfeeding populations found that:In a population in which mothers were receiving 'standard' antiretroviral for HIV infection a single dose of NVP given to mothers in labour plus a single dose of NVP given to babies immediately after birth ('HIVNET 012 regimen') compared with placebo did not result in a statistically significant difference in HIV infection rates at birth and at 4 to 8 weeks.The 'Thai CDC regimen' compared with the 'HIVNET 012 regimen' did not result in a significant difference in HIV infection at 4 to 8 weeks.A single dose of NVP given to babies immediately after birth compared to ZDV given to babies for the first 6 weeks after birth did not result in a significant difference in HIV infection rates at 4-8 weeks and 3 to 4 months. (ABSTRACT TRUNCATED)

Cell reservoirs of the Epstein-Barr virus in biopsy-proven lymphocytic interstitial pneumonitis in HIV-1 subtype E infected children: identification by combined in situ hybridization and immunohistochemistry

Lymphoid interstitial pneumonitis (LIP), a frequent pulmonary complication in human immune deficiency virus (HIV)-infected pediatric patients, is characterized histologically by marked infiltration of lymphoid cells. Several theories have been suggested that LIP may be caused by Epstein-Barr virus (EBV). To identify the reservoir of EBV and pathogenesis of lymphoid infiltrates in HIV subtype E infected pediatric LIP, we examined the distribution and expression of EBV in the inflammatory cell recruitment in surgical lung biopsy-proven LIP from 9 vertically HIV subtype E-infected pediatric patients. The dominant microscopic feature of LIP demonstrated widespread widening of alveolar septum by mononuclear inflammatory cell infiltrate mainly composed of mature lymphocytes and plasma cells surrounding airways and expanding to the lung interstitium. EBV-encoded RNA (EBER) in situ hybridization, performed from paraffin-embedded lung tissues, revealed positive intranuclear signals in all 9 LIP cases. Interestingly, combined immunohistochemical and in situ hybridization analyses in 6 out of 9 LIP cases revealed 30% to 50% of the Langerhans and related dendritic cells were infected with EBV, whereas <30% of the T and B cells were infected with EBV. These results suggested that a chronic antigenic stimulus of EBV played important roles in the pathogenesis of LIP in these patients. This supports the notion that Langerhans cells (LCs) are more readily infected with EBV, indicating that LCs are reservoirs for EBV in lungs of HIV subtype E-infected pediatric LIP. And possibly LCs may play an important role in the recruitment of inflammatory cell infiltrates, especially T cells into these tissues. In addition, HIV may provide a milieu or microenvironment for the evolution of LIP, which represent an immunologic response to EBV infection. Interactions between LCs and related dendritic cells together with T cells are important for effective HIV and EBV replications.

Clinical impact of HIV-1 subtype: are there important differences?

The enormous genetic diversity of HIV-1 is a major challenge to vaccine development and may have important clinical consequences. HIV-1 group M predominates globally, with nine subtypes, several sub-subtypes and over 30 circulating recombinant forms that may exhibit differences with respect to transmissibility, pathogenicity and development of antiretroviral resistance. Subtype D appears to be more virulent than other subtypes, in particular subtype A. Subtype C may be less virulent and more transmissible, although the evidence for this is inconclusive. All group M non-B subtypes appear to be equally susceptible to combination antiretroviral therapy, but development of resistance mutations may vary significantly between subtypes. Further research into the clinical implications of HIV-1 diversity is crucial for effective HIV-1 prevention and treatment.

Antiretrovirals for reducing the risk of mother-to-child transmission of HIV infection

BACKGROUND

Antiretroviral drugs (ARV) reduce viral replication and can reduce mother-to-child transmission of HIV either by lowing plasma viral load in pregnant women or through post-exposure prophylaxis in their newborns. In rich countries, highly active antiretroviral therapy (HAART) has reduced the vertical transmission rates to around 1-2%, but HAART is not yet widely available in low and middle income countries. In these countries, various simpler and less costly antiretroviral regimens have been offered to pregnant women or to their newborn babies, or to both.

OBJECTIVES

To determine whether, and to what extent, antiretroviral regimens aimed at decreasing the risk of mother-to-child transmission of HIV infection achieve a clinically useful decrease in transmission risk, and what effect these interventions have on maternal and infant mortality and morbidity.

SEARCH STRATEGY

We sought to identify all relevant studies regardless of language or publication status by searching the Cochrane HIV/AIDS Review Group Trials Register, The Cochrane Library, Medline, EMBASE and AIDSearch and relevant conference abstracts. We also contacted research organizations and experts in the field for unpublished and ongoing studies. The original review search strategy was updated in 2006.

SELECTION CRITERIA

Randomised controlled trials of any antiretroviral regimen aimed at decreasing the risk of mother-to-child transmission of HIV infection compared with placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently selected relevant studies, extracted data and assessed trial quality. For the primary outcomes, we used survival analysis to estimate the probability of infants being infected with HIV (the observed proportion) at various specific time-points and calculated efficacy at a specific time as the relative reduction in the proportion infected. Efficacy, at a specific time, is defined as the preventive fraction in the exposed group compared to the reference group, which is the relative reduction in the proportion infected: 1-(Re/Rf). For those studies where efficacy and hence confidence intervals were not calculated, we calculated the approximate confidence intervals for the efficacy using recommended methods. For analysis of results that are not based on survival analyses we present the relative risk for each trial outcome based on the number randomised. No meta-analysis was conducted as no trial assessed the identical drug regimens.

MAIN RESULTS

Eighteen trials including 14,398 participants conducted in 16 countries were eligible for inclusion in the review. The first trial began in April 1991 and assessed zidovudine (ZDV) versus placebo and since then, the type, dosage and duration of drugs to be compared has been modified in each subsequent trial. Antiretrovirals versus placebo In breastfeeding populations, three trials found that:ZDV given to mothers from 36 to 38 weeks gestation, during labour and for 7 days after delivery significantly reduced HIV infection at 4-8 weeks (Efficacy 32.00%; 95% CI 0.64 to 63.36), 3 to 4 months (Efficacy 34.00%; 95% CI 6.56 to 61.44), 6 months (Efficacy 35.00%; 95% CI 9.52 to 60.48), 12 months (Efficacy 34.00%; 95% CI 8.52 to 59.48) and 18 months (Efficacy 30.00%; 95% CI 2.56 to 57.44).ZDV given to mothers from 36 weeks gestation and during labour significantly reduced HIV infection at 4 to 8 weeks (Efficacy 44.00%; 95% CI 8.72 to 79.28) and 3 to 4 months (Efficacy 37.00%; 95% CI 3.68 to 70.32) but not at birth.ZDV plus lamivudine (3TC) given to mothers from 36 weeks gestation, during labour and for 7 days after delivery and to babies for the first 7 days of life (PETRA 'regimen A') significantly reduced HIV infection (Efficacy 63.00%; 95% CI 41.44 to 84.56) and a combined endpoint of HIV infection or death (Efficacy 61.00%; 95% CI 41.40 to 80.60) at 4 to 8 weeks but these effects were not sustained at 18 months.ZDV plus 3TC given to mothers from the start of labour until 7 days after delivery and to babies for the first 7 days of life (PETRA 'regimen B') significantly reduced HIV infection (Efficacy 42.00%; 95% CI 12.60 to 71.40) and HIV infection or death at 4 to 8 weeks (Efficacy 36.00%; 95% CI 8.56 to 63.44) but the effects were not sustained at 18 months.ZDV plus 3TC given to mothers during labour only (PETRA 'regimen C') with no treatment to babies did not reduce the risk of HIV infection at either 4 to 8 weeks or 18 months. In non-breastfeeding populations, three trials found that:ZDV given to mothers from 14 to 34 weeks gestation and during labour and to babies for the first 6 weeks of life significantly reduced HIV infection in babies at 18 months (Efficacy 66.00%; 95% CI 34.64 to 97.36).ZDV given to mothers from 36 weeks gestation and during labour with no treatment to babies ('Thai-CDC regimen') significantly reduced HIV infection at 4 to 8 weeks (Efficacy 50.00%; 95% CI 12.76 to 87.24) but not at birthZDV given to mothers from 38 weeks gestation and during labour with no treatment to babies did not influence HIV transmission at 6 months. Longer versus shorter regimens using the same antiretrovirals One trial in a breastfeeding population found that:ZDV given to mothers during labour and to their babies for the first 3 days of life compared with ZDV given to mothers from 36 weeks and during labour (similar to 'Thai-CDC') resulted in HIV infection rates that were not significantly different at birth, 4-8 weeks, 3 to 4 months, 6 months and 12 months. Three trials in non-breastfeeding populations found that:ZDV given to mothers from 28 weeks gestation during labour and to infants for the first 3 days after birth compared with ZDV given to mothers from 35 weeks gestation through labour and to infants from birth to 6 weeks significantly reduced HIV infection rate at 6 months (Efficacy 45.00%; 95% CI 1.88 to 88.12) but compared with the same regimen ZDV given to mothers from 28 weeks gestation through labour and to infants from birth to 6 weeks did not result in a statistically significant difference in HIV infection at 6 months. ZDV given to mothers from 35 weeks gestation during labour and to infants for the first 3 days after birth was considered ineffective for reducing transmission rates and this regimen was discontinued.An antenatal/intrapartum course of ZDV used for a median of 76 days compared with an antenatal/intrapartum ZDV regimen used for a median 28 days with no treatment to babies in either group did not result in HIV infection rates that were significantly different at birth and at 3 to 4 months. In a programme where mothers were routinely receiving ZDV in the third trimester of pregnancy and babies were receiving one week of ZDV therapy, a single dose of nevirapine (NVP) given to mothers in labour and to their babies soon after birth compared with a single dose of NVP given to mothers only resulted in HIV infection rates that were not significantly different at birth and 6 months. However the reduction in risk of HIV infection or death at 6 months was marginally significant (Efficacy 45.00%; 95% CI -4.00 to 94.00). Antiretroviral regimens using different drugs and durations of treatment In breastfeeding populations, three trials found that:A single dose of NVP given to mothers at the onset of labour plus a single dose of NVP given to their babies immediately after birth ('HIVNET 012 regimen') compared with ZDV given to mothers during labour and to their babies for a week after birth resulted in lower HIV infection rates at 4-8 weeks (Efficacy 41.00%; 95% CI 11.60 to 70.40), 3-4 months (Efficacy 39.00%; 95% CI 11.56 to 66.44), 12 months (Efficacy 36.00%; 95% CI 8.56 to 63.44) and 18 months (Efficacy 39.00%; 95% CI 13.52 to 64.48). In addition, the NVP regimen significantly reduced the risk of HIV infection or death at 4-8 weeks (Efficacy 42.00%; 95% CI 14.56 to 69.44), 3 to 4 months (Efficacy 40.00%; 95% CI 14.52 to 65.48), 12 months (Efficacy 32.00%; 95% CI 8.48 to 55.52) and 18 months (Efficacy 33.00%; 95% CI 9.48 to 56.52). The 'HIVNET 012 regimen' plus ZDV given to babies for 1 week after birth compared with the 'HIVNET 012 regimen' alone did not result in a statistically significant difference in HIV infection at 4 to 8 weeks.A single dose of NVP given to babies immediately after birth plus ZDV given to babies for 1 week after birth compared with a single dose of NVP given to babies only significantly reduced the HIV infection rate at 4 to 8 weeks (Efficacy 37.00%; 95% CI 3.68 to 70.32). Five trials in non-breastfeeding populations found that:In a population in which mothers were receiving 'standard' ARV for HIV infection a single dose of NVP given to mothers in labour plus a single dose of NVP given to babies immediately after birth ('HIVNET 012 regimen') compared with placebo did not result in a statistically significant difference in HIV infection rates at birth and at 4 to 8 weeks. The 'Thai CDC regimen' compared with the 'HIVNET 012 regimen' did not result in a significant difference in HIV infection at 4 to 8 weeks.A single dose of NVP given to babies immediately after birth compared to ZDV given to babies for the first 6 weeks of life did not result in a significant difference in HIV infection rates at 4-8 weeks and 3 to 4 months.ZDV plus 3TC given to mothers in labour and for a week after delivery and to their infants for a week after birth (similar to 'PETRA regimen B') compared with NVP given to mothers in labour and immediately after delivery plus a single dose of NVP to their babies immediately after birth (similar to 'HIVNET 012 regimen') did not result in a significant difference in the HIV infection rate at 4 to 8 weeks. (ABSTRACT TRUNCATED)