HIV-1 detection in cervicovaginal secretions during pregnancy

Understanding Viral and Immune Interplay During Vertical Transmission of HIV: Implications for Cure

Despite the significant progress that has been made to eliminate vertical HIV infection, more than 150,000 children were infected with HIV in 2019, emphasizing the continued need for sustainable HIV treatment strategies and ideally a cure for children. Mother-to-child-transmission (MTCT) remains the most important route of pediatric HIV acquisition and, in absence of prevention measures, transmission rates range from 15% to 45% via three distinct routes: in utero, intrapartum, and in the postnatal period through breastfeeding. The exact mechanisms and biological basis of these different routes of transmission are not yet fully understood. Some infants escape infection despite significant virus exposure, while others do not, suggesting possible maternal or fetal immune protective factors including the presence of HIV-specific antibodies. Here we summarize the unique aspects of HIV MTCT including the immunopathogenesis of the different routes of transmission, and how transmission in the antenatal or postnatal periods may affect early life immune responses and HIV persistence. A more refined understanding of the complex interaction between viral, maternal, and fetal/infant factors may enhance the pursuit of strategies to achieve an HIV cure for pediatric populations.

The role of cell-associated virus in mother-to-child HIV transmission

Mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV) continues to contribute to the global burden of disease despite great advances in antiretroviral (ARV) treatment and prophylaxis. In this review, we discuss the proposed mechanisms of MTCT, evidence for cell-free and cell-associated transmission in different routes of MTCT, and the impact of ARVs on virus levels and transmission. Many population-based studies support a role for cell-associated virus in transmission and in vitro studies also provide some support for this mode of transmission. However, animal model studies provide proof-of-principle that cell-free virus can establish infection in infants, and studies of ARVs in HIV-infected pregnant women show a strong correlation with reduction in cell-free virus levels and protection. ARV treatment in MTCT potentially provides opportunities to better define the infectious form of virus, but these studies will require better tools to measure the infectious cell reservoir.

The effect of genital tract infections on HIV-1 shedding in the genital tract: a systematic review and meta-analysis

This article reviews the effect of genital tract infections and associated clinical conditions on the detection and concentration of HIV-1 shedding in the genital tract. A search of the PubMed, Embase, and AIDSearch databases was conducted. Meta-analysis was performed on those studies that reported the effect of genital tract infections on the detection of HIV-1 shedding. Thirty-nine studies met the inclusion criteria. The odds of HIV-1 detection in the genital tract were increased most substantially by urethritis (OR 3.1, 95% CI: 1.1-8.6) and cervicitis (OR 2.7, 95% CI: 1.4-5.2). The odds of HIV-1 detection were also increased significantly in the presence of cervical discharge or mucopus (OR 1.8, 95% CI: 1.2-2.7), gonorrhoea (OR 1.8, 95% CI: 1.2-2.7), chlamydial infection (OR 1.8, 95% CI: 1.1-3.1), and vulvovaginal candidiasis (OR 1.8, 95% CI: 1.3-2.4). Other infections and clinical conditions were found to have no significant effect on the detection of HIV-1, although HSV-2 shedding was found to increase the concentration of HIV-1 shedding, and genital ulcer disease was found to increase the odds of HIV-1 detection significantly after excluding one biased study (OR 2.4, 95% CI: 1.2-4.9). This analysis shows that infections that are associated with significant increases in leukocyte concentrations in the genital tract are also associated with significant increases in HIV-1 shedding. These infections are likely to be particularly important in promoting the sexual transmission and mother-to-child intrapartum transmission of HIV-1, and should therefore be the focus of HIV prevention strategies.

Rapid and simple liquid chromatography tandem mass spectrometry method for the quantification of zidovudine in rat plasma

A high-performance liquid chromatography/electrospray ionization tandem mass spectrometry method was developed and validated for the quantification of zidovudine in rat plasma. Following solid-phase extraction, the analytes were separated using an isocratic mobile phase on a reverse phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M+H]+ ions, m/z 268/127 for zidovudine and m/z 230/112 for the internal standard. The method exhibited a linear dynamic range of 5-500 ng/mL for zidovudine in rat plasma. The lower limit of quantification was 5 ng/mL with a relative standard deviation of less than 8%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 1.5 min for each sample made it possible to analyze more than 400 plasma samples per day. The validated method was applied for pharmacokinetic studies of the novel drug delivery systems of zidovudine in rats.

N/A

N/A

Validation of performance of the gen-probe human immunodeficiency virus type 1 viral load assay with genital swabs and breast milk samples

Human immunodeficiency type 1 (HIV-1) continues to spread at an alarming rate. The virus may be transmitted through blood, genital secretions, and breast milk, and higher levels of systemic virus in the index case, as measured by plasma RNA viral load, have been shown to correlate with increased risk of transmitting HIV-1 both vertically and sexually. Less is known about the correlation between transmission and HIV-1 levels in breast milk or genital secretions, in part because reliable quantitative assays to detect HIV-1 in these fluids are not available. Here we show that the Gen-Probe HIV-1 viral load assay can be used to accurately quantify viral load in expressed breast milk and in cervical and vaginal samples collected on swabs. Virus could be quantified from breast milk and swab samples spiked with known amounts of virus, including HIV-1 subtypes A, C, and D. As few as 10 copies of HIV-1 RNA could be detected above background threshold levels in > or =77% of assays performed with spiked breast milk supernatants and mock swabs. In genital swab samples from HIV-1-infected women, similar levels of HIV-1 RNA were consistently detected in duplicate swabs taken from the same woman on the same clinic visit, suggesting that the RNA values from a single swab sample can be used to measure genital viral load.

Post-operative complications after caesarean section in HIV-infected women

This retrospective study evaluated complications associated with caesarean section in HIV-infected women. For each HIV-positive patient ( n=45) a control group of ten seronegative women ( n=450) was matched for age, number of foetuses, gestational age, indication for caesarean section, status of the membranes and kind of anaesthesia. All women delivered in the same hospital using a uniform protocol. We evaluated the duration of stay in hospital after operation, the need for antibiotics after caesarean section, the incidence of minor postoperative complications (mild anaemia, mild temperature or fever 24 h after surgery, wound haematoma or infection, urinary tract infection, endometritis) and major postoperative complications (severe anaemia, pneumonia, pleural effusion, peritonitis, sepsis, disseminated intravascular coagulation, thromboembolism). Most HIV-positive women (64.5%) had a complicated recovery after surgery. A higher incidence of major and minor postoperative complications were observed in the HIV-positive group than in the control group. There was a statistically significant greater incidence of mild anaemia, mild temperature or fever, urinary tract infection and pneumonia in the HIV-positive group. HIV-positive women with less than 500x10(6) CD4(+) lymphocytest/l had higher post-caesarean section morbidity than HIV-positive women with more than 500x10(6) CD4(+) lymphocytest/l. The median duration of hospital stay was significantly higher in the HIV-positive group (median 7 days) than in the HIV-negative group (median 4 days). The rate of HIV vertical transmission was 8.8%. Higher post-caesarean section morbidity was found in HIV-positive women than in controls. Unfortunately, the HIV-positive women (with low CD4 lymphocytes counts), whose infants theoretically will benefit most from caesarean delivery, are also the women who are most likely to experience post-operative complications.

Correlation coefficient estimation involving a left censored laboratory assay variable

When assessing a correlation between two exposure or biological marker variables, one sometimes encounters the problem of indeterminate values for one of the variables due to an assay detection limit. In this event, investigators often report correlation coefficients computed after removing the pairs involving non-detectable values, or after substituting some small constant for those values. These ad hoc practices can lead to bias in both point and confidence interval estimates of the true correlation coefficient. To address this issue, we consider two parametric techniques for estimating the correlation in the presence of left censoring for one of the variables. The first is a maximum likelihood approach, and the second is an adaptation of multiple imputation motivated primarily by potential benefits in confidence interval coverage. Both of the estimators studied reduce to the standard Pearson's correlation coefficient in the event of no censoring, and hence are valid in cases where this measure would be appropriate for the complete data. We assess these approaches empirically and contrast them with ad hoc methods for estimating the correlation between cervicovaginal human immunodeficiency virus (HIV) viral load measurements and CD4+ lymphocyte counts from HIV positive women enrolled in a clinical trial conducted in Bangkok, Thailand.

Prevalence and risk factors of cervicovaginal HIV shedding among HIV-1 and HIV-2 infected women in Dakar, Senegal

OBJECTIVES

To assess the risk determinants and prevalence of cervicovaginal shedding of HIV-1 and HIV-2 among women in Dakar, Senegal.

METHODS

We conducted a cross sectional study of 153 HIV seropositive female sex workers (FSW) and another 142 HIV seropositive women attending an infectious diseases unit, based on an interview, physical examination, and laboratory screening for major sexually transmitted infections (STI). Cervicovaginal lavage fluid was tested for HIV-RNA by means of nested PCR. Links between cervicovaginal shedding of HIV-1 and HIV-2 and sociodemographic, clinical, and laboratory variables were identified by using odd ratios and 95% confidence intervals. Logistic regression analysis was used to identify independent links with HIV shedding.

RESULTS

The detection rate of HIV-RNA in cervicovaginal lavage fluid was low among FSW, with no difference between HIV-1 (7/90: 8%) and HIV-2 (3/48: 6%). The rate was far higher among the other women (41%, 48/117; 33%, 7/21 for HIV-1 and HIV-2, respectively). In multivariate analysis, high plasma viral load (>40 000 copies/ml) (AOR = 2.4 (1.0-5.6) p = 0.04) and basic vaginal pH (AOR = 2.2 (1.3-3.7) p = 0.002) were independently associated with HIV-1 shedding. For HIV-2 a CD4 count < 200 cells x 10(6)/l was the only factor associated with the shedding of HIV-2 (AOR = 9.0 (0.9-93)). The genital shedding rate was higher with HIV-1 than with HIV-2 (OR = 2.1 (0.9-4.8), but this difference disappeared after adjustment for the CD4+ cell count (AOR = 1.2 (0.5-2.9)).

CONCLUSION

Advanced disease stage and immunosuppression are the major risk determinants for shedding of both HIV-1 and HIV-2. Basic vaginal pH is also a risk determinant for HIV-1 shedding.

Myeloid-related protein (MRP)-8 from cervico-vaginal secretions activates HIV replication

OBJECTIVES

To identify a substance found in female genital tract secretions that enhances HIV expression in infected cells.

DESIGN

Cervico-vaginal lavages (CVL), collected in sterile normal saline, were fractionated and tested for HIV-inducing activity using HIV-infected monocytes.

METHODS

To purify the component(s) of CVL that enhance HIV production, Mono-Q ion exchange chromatography followed by Superose-12 molecular sieve analysis, and SDS--PAGE were performed. The purified protein was identified by amino acid sequence analysis.

RESULTS

SDS--PAGE of bioactive fractions showed a 14 kDa polypeptide band. Amino acid sequence analysis of selected peptides from the 14 kDa band showed 100% homology with the myeloid-related protein (MRP)-8, an inflammatory protein found in mucosal secretions. Western blot analysis revealed that bioactive CVL contained more immunoreactive MRP-8 than samples without bioactivity. The HIV-inducing activity of MRP-8 was further confirmed by showing that human recombinant MRP-8 increased HIV expression by up to 40-fold.

CONCLUSIONS

MRP-8 in cervico-vaginal secretions stimulates HIV production. Strategies aimed at blocking MRP-8 activity in the genital tract could reduce risk of sexual as well as maternal--infant transmission of HIV.

[Management of pregnant women infected with HIV at Bichat Hospital between 1990 and 1998: analysis of 202 pregnancies]

OBJECTIVE

To describe medical and obstetrical prenatal care of pregnant women infected by HIV-1 emphasizing the role of cesarean section.

DESIGN

A retrospective study of 202 pregnancies followed between 1990 and 1998 in a french hospital in Paris.

RESULTS

56.9% of the women were born in subsaharian Africa; 80.2% were infected by sexual intercourse and the seropositivity was discovered during the pregnancy in 51% of the cases. Viral coinfections by hepatitis B virus, hepatitis C virus and Human papillomavirus were found respectively in 14.7%, 16.5% and 13% of the pregnancies. Prematurity occurred in 15% of the deliveries. Efficacy of antiretroviral therapy was confirmed in this study: 5.7% of the children were infected despite the antiretrovial treatment versus 19.3% without treatment (p < 0.03). Prophylactic cesarean section was proposed to the patients since 1994; the morbidity of cesarean was 8.8% (69 cesarean sections).

CONCLUSION

The policy of the association of prophylactic cesarean section and monotherapy by Zidovudine is validated by recent studies. The extension of prophylatic cesarean section to all the pregnant women infected by HIV is proposed. However the evaluation of the morbidity of the cesarean section in HIV infected women needs a prospective case-control study.

Exposure to HIV-1 during delivery and mother-to-child transmission

BACKGROUND

The correlation between the presence of HIV-1 in maternal cervicovaginal secretions and in the infant's oro-pharyngal secretions at birth, and mother-to-child HIV transmission (MTCT) were examined to obtain a better understanding of its mechanism.

METHODS

Women without medical and obstetrical complications, living within a reasonable distance of the government hospital in Mombasa, Kenya, were recruited after informed consent. Maternal and infant characteristics were collected. Polymerase chain reaction was used to detect HIV-1 in cervico-vaginal and oro-pharyngal secretions. Infants were tested for HIV-1 by polymerase chain reaction within 48 h and at 6 weeks after delivery.

RESULTS

Between April 1998 and April 1999, 228 woman-infant pairs were included in the study. HIV-1 DNA in cervico-vaginal secretions was independently associated with HIV-1 maternal viral load and with infant birth-weight, whereas HIV-1 RNA was associated with maternal viral load and maternal age. HIV-1 DNA in the oropharyngal secretions was also independently associated with maternal viral load. MTCT rate at the age of 6 weeks was 23.6%. Intrapartum and early postpartum HIV transmission was independently associated with maternal viral load [adjusted odds ratio (OR), 1.6; 95% confidence interval (CI),1.0-2.7], detection of HIV-1 RNA in cervico-vaginal secretions (adjusted OR, 3.2; 95% CI, 1.5-7.3) and of HIV-1 DNA in oro-pharyngeal secretions (adjusted OR, 3.2; 95% CI, 1.1-9.0).

DISCUSSION

As far as is known, this is the first study showing that infant exposure to HIV-1 in the birth canal and the presence of HIV-infected cells in the infant's oropharyngeal cavity are independently associated with intrapartum and early postpartum MTCT. It supports the hypothesis that MTCT could occur through the oral route.

Detection and quantitation of human immunodeficiency virus type 1 in the female genital tract. The Division of AIDS Treatment Research Initiative 009 Study Group

Human immunodeficiency virus type 1 (HIV-1) was detected in the genital tracts of 59% of 225 women by RNA PCR and in 7% of the women by culture. In a comparison of two sampling methods, endocervical swabs were more sensitive than cervicovaginal lavage for HIV-1 RNA detection by PCR but not by culture and their sensitivity was independent of the concentration of HIV-1 RNA.

Simultaneous determination of lamivudine and zidovudine concentrations in human seminal plasma using high-performance liquid chromatography and tandem mass spectrometry

A HPLC-MS-MS method was developed and validated to measure lamivudine and zidovudine simultaneously in small volumes of human seminal plasma. Sample preparation was simple and rapid, requiring 25 microl of sample, the use of isotopically labeled lamivudine and zidovudine as internal standards and ultrafiltration through a molecular mass cut-off membrane. Lamivudine and its internal standard were separated from zidovudine and its internal standard with isocratic HPLC. Detection was carried out using tandem mass spectrometry. This validated method was used to analyze seminal samples obtained from six HIV-positive patients prescribed lamivudine and zidovudine.

Effect of highly active antiretroviral therapy on cervicovaginal HIV-1 RNA

OBJECTIVES

To determine the frequency of cervicovaginal lavage and plasma HIV-1 RNA levels that are below detectable levels (< 400 copies/ml) among women on highly active antiretroviral therapy (HAART), non-HAART and on no therapy. To compare the effect of initiating HAART on the timing of HIV-1 RNA suppression in the blood plasma and genital tract among antiretroviral-naïve women.

METHODS

Data were obtained from 205 HIV-infected women with paired plasma and cervicovaginal lavage viral load measurements. Seven antiretroviral-naïve women starting HAART had viral load measurements performed daily for one week, at 2 weeks and at 1 month after initiating therapy. Viral load quantification was carried out by nucleic acid sequence-based amplification assay. The lower limit of detection was 400 copies/ml.

RESULTS

Plasma and cervicovaginal HIV-1 RNA was detectable in 71 and 26% of the women, respectively. Among women with plasma viral loads less than 400, 400-9999, and 10,000 copies/ml or over, genital tract HIV-1 RNA was detected in 3, 17 and 48%, respectively (P < 0.001). Fifty-one per cent of the women with CD4 cell counts of less than 200/mm3 had detectable cervicovaginal viral loads compared with 18% among women with CD4 cell counts of 200/mm3 or over (P < 0.001). Cervicovaginal HIV-1 RNA was less than 400 copies/ml in 85% of those on HAART, 69% of those on non-HAART and 69% of those on no therapy (P < 0.045). In seven antiretroviral-naïve women initiating HAART, cervicovaginal HIV-1 RNA decreased by 0.7-2.1 log10 within 1-14 days of starting therapy.

CONCLUSION

The cervicovaginal HIV-1 RNA level was positively correlated with plasma HIV-1 RNA and negatively with the CD4 cell count. The use of HAART was significantly associated with below-detectable levels of HIV-1 RNA in both plasma and the genital tract. HIV-1 RNA suppression in the genital tract may occur rapidly after initiating therapy.

Frequent detection of HIV-1 in the gastric aspirates of neonates born to HIV-infected mothers

OBJECTIVE

To evaluate the frequency and correlates of oral route exposure of infants born to HIV-1-infected women.

METHODS

A multicenter study was performed within the prospective French Perinatal Cohort Study of mother-to-child HIV transmission. Oropharyngeal and gastric aspirates from 122 neonates were studied by reverse transcriptase (RT) polymerase chain reaction (PCR) for the presence of HIV-1, as well as for standard microbiology (Gram staining and culture).

RESULTS

Aspirates from 101 neonates were analyzed by RT-PCR; 28% of these were positive for HIV RNA. Another 21 aspirates could not be tested because of PCR inhibition. The median concentration of HIV RNA in the positive aspirates was 126 copies/ml (range: 8-1270). Detection of HIV-1 in the aspirate was significantly related to high maternal plasma-viral load, presence of blood in the aspirate, positive Gram stain or culture, episiotomy or perineal lesions, and sexually transmitted infections during the pregnancy. Most of the mothers received zidovudine prophylaxis during pregnancy and delivery. Among the six infants who were infected with HIV, three had positive aspirates. Of the three assumed to have acquired the infection intrapartum, only one had an HIV RNA-positive aspirate.

CONCLUSION

Exposure of the fetus to HIV via the oral route occurs frequently, even in the presence of zidovudine prophylaxis, and is likely to be one of the mechanisms of intrapartum transmission, but not the only one.

Quantitative assessment of cell-associated and cell-free virus in cervicovaginal samples of HIV-1-infected women

OBJECTIVE

To examine the amount of cell-free and cell-associated virus in cervicovaginal secretions (CVS) of HIV-infected women.

METHODS

Paired cervicovaginal and blood samples from 61 seropositive women were quantitatively evaluated by competitive polymerase chain reaction (cPCR) and reverse transcription-PCR (cRT-PCR) for: (1) genomic RNA from plasma and cell-free CVS, and (2) unspliced (u/s) RNA transcripts and proviral DNA in cells from secretions.

RESULTS

HIV DNA was detected in 42.6%, u/s transcripts in 32.7% and cell-free HIV RNA in 31.1% of 61 cervicovaginal samples. The median copy numbers of HIV DNA, u/s transcripts, and cell-free RNA were 125 copies/10(5) cells, 40 copies/10(5) cells, and 300 copies/mL of secretion, respectively. Nineteen of 26 (73.1%) and 17 of 26 (65.3%) women positive for DNA were also positive for RNA transcripts and cell-free RNA, respectively (P<0.001). A significant correlation between the amounts of cell-free and u/s transcripts was also found (Spearman Rho 0.618, P=0.014). The prevalences of u/s transcripts and cell-free RNA were 42.6% and 53.8% respectively among patients with detectable blood RNA, and 22.9% (P=0.09) and 14.3% (P=0.0017) among patients with undetectable blood RNA. In stepwise logistic regression, cell-free RNA was independently associated with the presence of detectable blood viremia. The amount of HIV DNA was lower among subiects currently under treatment (50 copies/10(5) cells) than in untreated subjects (250 copies/10(5) cells) (P=0.037).

CONCLUSIONS

Both cell-free and cell-associated HIV could be detected and quantitated in CVS, providing a means to examine the level of viral activity in the female genital tract.

HIV-1 RNA in plasma and genital tract secretions in women infected with HIV-1

To assess antiretroviral therapy, all compartments, including the genital tract, need to be evaluated. HIV-1 RNA was quantified in whole cervicovaginal lavage fluid (CVL) and plasma of 56 women and in the cellular and supernatant fractions of 27 of these women. Overall, we detected HIV-1 RNA in 59% of whole CVL samples and in 61% and 44% of cellular and supernatant fractions of the subset of women, respectively. Detectability of HIV-1 RNA in CVL increased with increasing level of plasma RNA in both unfractionated and cell-associated CVL components (p = .0004 and .002, respectively), but not in the cell-free fraction (p = .29). Mean HIV-1 RNA levels in CVL increased with decreasing CD4 counts (p = .002,) and with increasing plasma HIV-1 RNA (p < .001). Adjusted odds ratios (OR) for detectable CVL RNA were highest for women with CD4 counts <200 cells/mm3 (OR, 10.1; 95% confidence interval [CI]: 1.6-82.7; p = .02) and >50,000 copies/ml of plasma RNA (OR, 25.2; 95% CI, 3.2-554; p = .01). Treatment did not seem to affect RNA detection in CVL after adjusting for plasma RNA and CD4. In conclusion, we found that detectability and level of CVL RNA were closely associated with the cellular fraction of genital secretions in women and strongly correlated with the level of plasma RNA and CD4. Genital tract secretions may need to be tested in the assessment of treatment efficacy and this can easily be accomplished with this rapid and easy procedure using whole CVL.

Efficient isolation of human immunodeficiency virus type 1 RNA from cervical swabs

An efficient method for the isolation of human immunodeficiency virus type 1 (HIV-1) nucleic acids from dry cervical swabs was developed. HIV-1 gag and env were detected in 96% (25 of 26) and 81% (21 of 26), respectively, of the samples tested by PCR from HIV-1-seropositive women in a Kenyan cohort study. Eighty-eight percent of the swabs (22 of 25) were positive for gag RNA, and 85% (17 of 20) were positive for env RNA. Fewer than 1,000 copies of HIV-1 gag RNA were detected in four swabs in which a competitive quantitative PCR assay was used. The method described here may be useful for both qualitative and quantitative analyses of HIV RNA in mucosal secretions as well as amplification and cloning of full-length viral genes for functional studies.

Vertical transmission of viral infections

A variety of congenital viral infections are responsible for a large proportion of the mortality and morbidity in infancy and childhood. Vertical transmission may occur during primary maternal infection or during chronic or recurrent infection, with different implications for counselling and testing in pregnancy. Strategies for the diagnosis and prevention of mother-to-child transmission differ according to the timing and mechanisms involved. As demonstrated by hepatitis B research in the past and human immunodeficiency virus today, multicenter cohort studies and clinical trials are a key to developing effective interventions.