Human papillomavirus infects placental trophoblast and Hofbauer cells, but appears not to play a causal role in miscarriage and preterm labor

Association between human papillomavirus and preterm delivery: A systematic review and meta-analysis

INTRODUCTION

The lifetime prevalence of human papillomavirus infection (HPV) is estimated to be around 80% and it is the most common sexually transmitted infection. Despite being well known for its oncologic relevance, it has been associated with adverse pregnancy outcomes, though available evidence is contradicting. Previous meta-analyses involved articles which based HPV infection on Pap smear results, leading to a significant source of bias. Therefore, we aimed to assess the burden of genetically proven HPV infection on adverse pregnancy outcomes.

MATERIAL AND METHODS

In our meta-analysis, pregnant women tested for HPV DNA were only considered eligible. We conducted a systematic search in three major databases (PubMed, Embase, and CENTRAL) on September 22, 2023. Cohort, cross-sectional, and case-control studies were eligible for the analysis. The exposed group consisted of HPV-infected patients. We assessed the odds ratios (OR) with a confidence interval (CI) of 95%. In order to reduce the heterogeneity, we performed subgroup analyses based on different strains (high risk HPV, HPV 16/18, study design). The study was prospectively registered on PROSPERO (CRD42022370228).

RESULTS

Our study involved 14 articles with 7008 women. A significant association was found between preterm delivery and HPV infection (OR: 1.94, CI: 1.31-2.87). No significant association was found when separately examining high-risk HPV-infected women (OR: 1.94, CI: 0.82-4.59), and HPV 16 or 18-infected women (OR: 2.08, CI: 0.50-8.63) in terms of preterm delivery. No significant association was found between spontaneous abortion and HPV infection (OR: 1.02, CI: 0.16-6.31).

CONCLUSIONS

Our analysis indicates an association between HPV infection and preterm delivery. It is imperative that future studies consider confounding variables more comprehensively. Additionally, the global implementation of HPV vaccination programs holds significance not only in oncology but also in obstetrics.

Placental human papillomavirus infections and adverse pregnancy outcomes

INTRODUCTION

Knowledge on prevalence and association of human papillomavirus (HPV) in third trimester placentae and adverse pregnancy outcomes is limited. We investigated the prevalence of placental HPV at delivery, explored urine HPV characteristics associated with placental HPV and whether placental HPV increased the risk adverse pregnancy outcomes.

METHODS

Pregnant women were enrolled in the Scandinavian PreventADALL mother-child cohort study at midgestation. Human papillomavirus genotyping was performed on placental biopsies collected at delivery (n = 587) and first-void urine at midgestation and delivery (n = 556). Maternal characteristics were collected by questionnaires at gestational week 18 and 34. Adverse pregnancy outcomes were registered from chart data including hypertensive disorders of pregnancy, gestational diabetes mellitus and newborns small for gestational age. Uni- and multivariable regression models were used to investigate associations.

RESULTS

Placental HPV was detected in 18/587 (3 %). Twenty-eight genotypes were identified among the 214/556 (38 %) with midgestational urine HPV. Seventeen of the 18 women with placental HPV were midgestational HPV positive with 89 % genotype concordance. Midgestational high-risk-(HR)-HPV and high viral loads of Any- or HR-HPV were associated with placental HPV. Persisting HPV infection from midgestation to delivery was not associated with placental HPV. Adverse pregnancy outcomes were seen in 2/556 (0.4 %) of women with placental HPV.

DISCUSSION

In this general cohort of pregnant women, the prevalence of placental HPV was 3 %, and midgestational urinary HPV 38 %. High HPV viral load increased the risk for placental HPV infections. We observed no increased risk for adverse pregnancy outcomes in women with placental HPV.

Vertical Intrauterine Bovine and Ovine Papillomavirus Coinfection in Pregnant Cows

There is very little information available about transplacental infections by the papillomavirus in ruminants. However, recent evidence has emerged of the first report of vertical infections of bovine papillomavirus (BPV) in fetuses from naturally infected, pregnant cows. This study reports the coinfection of BPV and ovine papillomavirus (OaPV) in bovine fetuses from infected pregnant cows suffering from bladder tumors caused by simultaneous, persistent viral infections. Some molecular mechanisms involving the binary complex composed of Eras and platelet-derived growth factor β receptor (PDGFβR), by which BPVs and OaPVs contribute to reproductive disorders, have been investigated. A droplet digital polymerase chain reaction (ddPCR) was used to detect and quantify the nucleic acids of the BPVs of the Deltapapillomavirus genus (BPV1, BPV2, BPV13, and BPV14) and OaPVs belonging to the Deltapapillomavirus (OaPV1, OaPV2, and OaPV4) and Dyokappapapillomavirus (OaPV3) genera in the placenta and fetal organs (heart, lung, liver, and kidneys) of four bovine fetuses from four pregnant cows with neoplasia of the urinary bladder. A papillomaviral evaluation was also performed on the bladder tumors and peripheral blood of these pregnant cows. In all fetal and maternal samples, the genotype distribution of BPVs and OaPVs were evaluated using both their DNA and RNA. A BPV and OaPV coinfection was seen in bladder tumors, whereas only BPV infection was found in peripheral blood. The genotype distribution of both the BPVs and OaPVs detected in placentas and fetal organs indicated a stronger concordance with the viral genotypes detected in bladder tumors rather than in peripheral blood. This suggests that the viruses found in placentas and fetuses may have originated from infected bladders. Our study highlights the likelihood of vertical infections with BPVs and OaPVs and emphasizes the importance of gaining further insights into the mechanisms and consequences of this exposure. This study warrants further research as adverse pregnancy outcomes are a major source of economic losses in cattle breeding.

Assisted reproductive technology treatment failure and the detection of intrauterine HPV through spent embryo transfer media sample

Cervical human papillomavirus (HPV) infection is believed to increase the risks of pregnancy failure and abortion, however, whether the uterine cavity HPV infection reduces pregnancy rate or increases miscarriage rate remains unclarified in infertile women undergoing assisted reproductive technology (ART) treatment. Therefore, we aimed to assess ART outcomes in the presence of intrauterine HPV. This was a hospital-based multicenter (five reproductive medicine centers) matched cohort study. This study involved 4153 infertile women undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection treatment in five reproductive medicine centers between October 2018 and 2020. The spent embryo transfer media sample with endometrium tissue were collected and performed with flow-through hybridization and gene chips to detect HPV DNA. According to basic characteristics, HPV-positive and negative patients were matched in a ratio of 1:4 by age, body mass index transfer timing, transfer type, and number of embryos transferred. The primary outcome was pregnancy and clinical miscarriage rates in the transfer cycle underwent HPV detection. 92 HPV-positive and 368 HPV-negative patients were screened and analyzed statistically. Univariate analysis showed uterine cavity HPV infection resulted in lower rates of ongoing pregnancy (31.5% vs. 44.6%; p = 0.023), implantation (32.3% vs. 43.1%; p = 0.026), biochemical pregnancy (47.8% vs. 62.5%; p = 0.010), and clinical pregnancy (40.2% vs. 54.3%; p = 0.015) compared with HPV negative group. The infertile female with positive HPV also had a slightly higher frequency of biochemical miscarriage (15.9% vs. 13.0%; p = 0.610) and clinical miscarriage (24.3% vs. 15.5%; p = 0.188). These findings suggest that HPV infection in the uterine cavity is a high risk for ART failure. HPV screening is recommended before ART treatment, which may be benefit to improving pregnancy outcome.

Association between Human Papillomavirus 16 Viral Load in Pregnancy and Preterm Birth

Recent evidence shows increased preterm birth risk with human papillomavirus-16 (HPV16) infection during pregnancy. This study aimed to measure the association between HPV16 viral load during pregnancy and preterm birth. We used data from participants in the HERITAGE study. The Linear Array assay was used for HPV DNA testing on vaginal samples collected during the first and third trimesters of pregnancy. The HPV16 viral load was measured with a real-time polymerase chain reaction. We used logistic regression to measure the associations between HPV16 viral load during pregnancy and preterm birth (defined as birth before 37 weeks of gestation). The adjusted odd ratios (aORs) and the 95% confidence intervals [CIs] were estimated with inverse probability treatment weighting of the propensity score. This study included 48 participants who tested positive for HPV16 during the first trimester of pregnancy. The aOR for the association between first-trimester HPV16 viral load (higher viral load categorized with a cutoff of 0.5 copy/cell) was 13.04 [95% CI: 1.58-107.57]). Similar associations were found using different cutoffs for the categorization of viral load during the first and third trimesters. Our findings suggest a strong association between a high HPV16 viral load during pregnancy and preterm birth, demonstrating a biological gradient that reinforces the biological plausibility of a causal association.

Unraveling Immunological Dynamics: HPV Infection in Women-Insights from Pregnancy

During pregnancy, hormonal and immune adaptations are vital for supporting the genetically distinct fetus during elevated infection risks. The global prevalence of HPV necessitates its consideration during pregnancy. Despite a seemingly mild immune response, historical gestational viral infections underscore its significance. Acknowledging the established HPV infection risks during pregnancy, our review explores the unfolding immunological changes in pregnant women with HPV. Our analysis aims to uncover strategies for safely modulating the immune system, mitigating adverse pregnancy consequences, and enhancing maternal and child health. This comprehensive narrative review delves into the existing knowledge and studies on this topic.

Risk factors for placental human papillomavirus infection

OBJECTIVE

Human papillomavirus (HPV) has been associated with adverse pregnancy outcomes but placental HPV infection has been rarely studied. The objective was to determine the proportion of HPV-positive placentas and the associated risk factors among HPV-positive women during pregnancy.

METHODS

We analysed data from pregnant women enrolled in HERITAGE cohort study between 2010 and 2016 with positive vaginal HPV infection during the first trimester of pregnancy (n=354). Placental swabs and biopsies were collected. HPV genotyping was performed using Linear Array. The predictors of placental HPV detection were identified by generalised estimating equations models.

RESULTS

HPV was detected in 78 placentas (22.0%) (one among 96 caesarean sections and 77 among 258 vaginal deliveries). Overall, 91% of HPV-positive placentas were positive for a genotype that was detected in vaginal samples during pregnancy. Among women who delivered vaginally, abnormal cytology (adjusted OR (aOR) 1.78 (95% CI 1.02 to 3.10)), other genitourinary infection (aOR 2.41 (95% CI 1.31 to 4.44)), presence of multiple HPV genotypes in the first trimester (aOR 2.69 (95% CI 1.76 to 4.12)) and persistence of high-risk HPV infections during pregnancy (HPV-16/18: aOR 3.94 (95% CI 2.06 to 7.55) and other than HPV-16/18: aOR 2.06 (95% CI 1.05 to 4.02)) were independently associated with placental HPV.

CONCLUSIONS

HPV was frequently detected in the placenta of women who delivered vaginally and may be associated with host immune response characteristics.

The Innate Defense in the Zika-Infected Placenta

Zika virus (ZIKV) is an arthropod-borne virus that belongs to the Flaviviridae family, genus Flavivirus and was first isolated 1947 in Uganda, Africa, from the serum of a sentinel Rhesus monkey. Since its discovery, the virus was responsible for major outbreaks in several different countries, being linked to severe complications in pregnant women, neonatal birth defects and the congenital zika syndrome. Maternal-fetal transmission of ZIKV can occur in all trimesters of pregnancy, and the role of the placenta and its cells in these cases is yet to be fully understood. The decidua basalis and chorionic villi, maternal-fetal components of the placenta, contain a rich immunological infiltrate composed by Hofbauer cells, mastocytes, dendritic cells and macrophages, primary cells of the innate immune response that have a role that still needs to be better investigated in ZIKV infection. Recent studies have already described several histopathological features and the susceptibility and permissiveness of placenta cells to infection by the Zika virus. In this review, we address some of the current knowledge on the innate immune responses against ZIKV, especially in the placenta.

Harnessing Human Papillomavirus’ Natural Tropism to Target Tumors

Human papillomaviruses (HPV) are small non-enveloped DNA tumor viruses established as the primary etiological agent for the development of cervical cancer. Decades of research have elucidated HPV’s primary attachment factor to be heparan sulfate proteoglycans (HSPG). Importantly, wounding and exposure of the epithelial basement membrane was found to be pivotal for efficient attachment and infection of HPV in vivo. Sulfation patterns on HSPG’s become modified at the site of wounds as they serve an important role promoting tissue healing, cell proliferation and neovascularization and it is these modifications recognized by HPV. Analogous HSPG modification patterns can be found on tumor cells as they too require the aforementioned processes to grow and metastasize. Although targeting tumor associated HSPG is not a novel concept, the use of HPV to target and treat tumors has only been realized in recent years. The work herein describes how decades of basic HPV research has culminated in the rational design of an HPV-based virus-like infrared light activated dye conjugate for the treatment of choroidal melanoma.

Maternal HPV Infection and the Estimated Risks for Adverse Pregnancy Outcomes—A Systematic Review

Background: Human Papilloma Virus (HPV) represents the most prevalent genital infection in young women of reproductive age. Objective: This systematic review aims to estimate the effect of HPV infection during pregnancy and assess the correlation between HPV and adverse pregnancy outcomes. Materials and methods: The search strategy has been developed based on the PICOS framework: Population (pregnant women infected with HPV), Intervention (HPV infection confirmed by molecular tests), Comparator (pregnant women without HPV infection), Outcomes (adverse pregnancy outcomes) and Study design (observational studies). We searched PubMed, Web of Science, and Scopus databases on 8 January 2022 by using the following keywords: “HPV”, “prematurity”, “preterm birth”, “miscarriage”, “premature rupture of membranes”, “adverse pregnancy outcome”, “low birth weight”, “fetal growth restriction”, “pregnancy-induced hypertensive disorders”, “preeclampsia”. Selection criteria were HPV infection confirmed within maximum 2 years before pregnancy with a molecular test and adverse pregnancy outcomes. (Results: Although numerous studies are conducted on this topic, data are still controversial regarding identifying maternal HPV infection as a risk factor for adverse pregnancy outcomes. More prospective large cohort studies are needed to prove a causative relationship.

Maternal condyloma acuminata infection in pregnancy and offspring long-term respiratory and infectious outcome

BACKGROUND

Maternal condyloma acuminata infection may be vertically transmitted to the offspring during pregnancy and childbirth. Our study aimed to investigate the possible impact of maternal condyloma acuminata infection in pregnancy on offspring respiratory and infectious morbidity.

METHODS

A population-based cohort analysis including all singleton deliveries occurring between 1991 and 2014 at a tertiary medical center. Long-term infectious and respiratory morbidities were compared between children with and without exposure to maternal condyloma infection during pregnancy. A Kaplan-Meier survival curve was used to compare cumulative hospitalization rate and a Cox regression analyses to control for confounders.

RESULTS

No significant differences were found in total respiratory and infectious related hospitalizations between the study groups. The survival curves demonstrated no difference in the cumulative incidence between the two groups in both respiratory hospitalizations (log-rank, p = 0.18) and infectious hospitalizations (log-rank, p = 0.95). Cox multivariable analyses demonstrated that exposure to maternal condyloma infection during pregnancy is not a risk factor for neither infectious (aHR 0.91, [CI] 0.49-1.69) nor respiratory (aHR 0.37, [CI] 0.09-1.51) morbidity during childhood and adolescence.

CONCLUSION

Exposure to maternal condyloma infection during pregnancy does not appear to be an independent risk factor for later respiratory or infectious morbidity throughout childhood and adolescence.

To evaluate the role of placental human papilloma virus (HPV) infection as a risk factor for spontaneous preterm birth: a prospective case control study

OBJECTIVES

i) To compare the placental human papilloma virus (HPV) deoxynucleic acid (DNA) status of preterm deliveries with full term deliveries and to identify high risk (HR) genotypes (HPV 16 and 18); and ii) To compare the perinatal outcomes of HPV positive with HPV negative pregnant women.

METHODS

A case control study was carried out on 100 antenatal women with singleton live pregnancies admitted in labor ward of a tertiary care teaching hospital from April 2017 to March 2018. The two study groups were i) spontaneous preterm deliveries between 24 and 36 + 6 weeks (n=50) and ii) full term deliveries ≥37 weeks (n=50). The placental tissue was analysed for HPV DNA and HR HPV genotypes were detected by type specific primers. A comparative analysis of perinatal outcomes between HPV positive and negative women was done.

RESULTS

An overall placental tissue HPV prevalence of 12% (12/100) was observed in study cohort which was not significantly different between preterm and full term deliveries (16 vs. 8%, p=0.218). HPV 16 was significantly associated with preterm births (p=0.04). Both HPV affected and non-affected women were comparable in terms of mode of delivery and neonatal outcomes. However, a statistically significant association of preterm neonatal intensive care admissions with HR HPV 16 genotype was observed (p=0.04).

CONCLUSIONS

Spontaneous preterm births can be attributed to placental HPV infection, specifically HR HPV 16 genotype. This association identifies a potentially preventable cause of prematurity and its associated complications, in wake of availability of an effective vaccine.

Potential role of viral infections in miscarriage and insights into the underlying molecular mechanisms

Intrauterine viruses can infect the decidua and placenta and cause adverse effects on the fetus during gestation. This review discusses the contribution of various viral infections to miscarriage and the molecular mechanisms by which viruses can cause devastating effects on healthy fetuses and induce miscarriage. Severe acute respiratory syndrome coronavirus 2 as newly emerged coronavirus was considered here, due to the concerns about its role during pregnancy and inducing miscarriage, as well. In this narrative review, an extensive literature search was conducted to find all studies investigating viral infections in miscarriage and their molecular mechanisms published over the past 20 years. The results of various studies investigating the roles of 20 viral infections in miscarriage are presented. Then, the mechanisms of pregnancy loss in viral infections were addressed, including alteration of trophoblast invasion and placental dysfunction, inducing excessive maternal immune response, and inducing apoptosis in the placental tissue. Viruses may cause pregnancy loss through different mechanisms and our knowledge about these mechanisms can be helpful for controlling or preventing viral infections and achieving a successful pregnancy.

Placental Macrophage (Hofbauer Cell) Responses to Infection During Pregnancy: A Systematic Scoping Review

BACKGROUND

Congenital infection of the fetus via trans-placental passage of pathogens can result in severe morbidity and mortality. Even without transmission to the fetus, infection of the placenta itself is associated with pregnancy complications including pregnancy loss and preterm birth. Placental macrophages, also termed Hofbauer cells (HBCs), are fetal-origin macrophages residing in the placenta that are likely involved in responding to placental infection and protection of the developing fetus. As HBCs are the only immune cell present in the villous placenta, they represent one of the final opportunities for control of infection and prevention of passage to the developing fetus.

OBJECTIVE AND RATIONALE

The objective of this review was to provide a systematic overview of the literature regarding HBC responses during infection in pregnancy, including responses to viral, bacterial, and parasitic pathogens.

METHODS

PubMed and Scopus were searched on May 20th, 2021, with no limit on publication date, to identify all papers that have studied placental macrophages/Hofbauer cells in the context of infection. The following search strategy was utilized: (hofbauer* OR "hofbauer cells" OR "hofbauer cell" OR "placental macrophage" OR "placental macrophages") AND [infect* OR virus OR viral OR bacteri* OR parasite* OR pathogen* OR LPS OR "poly(i:c)" OR toxoplasm* OR microb* OR HIV)].

OUTCOMES

86 studies were identified for review. This included those that investigated HBCs in placentas from pregnancies complicated by maternal infection and in vitro studies investigating HBC responses to pathogens or Pathogen-Associated Molecular Patterns (PAMPs). HBCs can be infected by a variety of pathogens, and HBC hyperplasia was a common observation. HBCs respond to pathogen infection and PAMPs by altering their transcriptional, translational and secretion profiles. Co-culture investigations demonstrate that they can replicate and transmit pathogens to other cells. In other cases, they may eliminate the pathogen through a variety of mechanisms including phagocytosis, cytokine-mediated pathogen elimination, release of macrophage extracellular traps and HBC-antibody-mediated neutralization. HBC responses differ across gestation and may be influenced by pre-existing immunity. Clinical information, including gestational age at infection, gestational age of the samples, mode of sample collection and pregnancy outcome were missing for the majority of studies.

Maternal HPV Infection: Effects on Pregnancy Outcome

The human papilloma virus (HPV) infection, caused by a ubiquitous virus typically transmitted through the direct contact of infected organs, either through the skin or mucosa, is the most common sexually transmitted infection, placing young women at a high risk of contracting it. Although the vast majority of cases spontaneously clear within 1-2 years, persistent HPV infection remains a serious concern, as it has repeatedly been linked to the development of multiple malignancies, including cervical, anogenital, and oropharyngeal cancers. Additionally, more recent data suggest a harmful effect of HPV infection on pregnancy. As the maternal hormonal environment and immune system undergo significant changes during pregnancy, the persistence of HPV is arguably favored. Various studies have reported an increased risk of adverse pregnancy outcomes among HPV-positive women, with the clinical impact encompassing a range of conditions, including preterm birth, miscarriage, pregnancy-induced hypertensive disorders (PIHD), intrauterine growth restriction (IUGR), low birth weight, the premature rupture of membranes (PROM), and fetal death. Therefore, understanding the mechanisms employed by HPV that negatively impact pregnancy and assessing potential approaches to counteract them would be of interest in the quest to optimize pregnancy outcomes and improve child survival and health.

Association Between Human Papillomavirus Infection Among Pregnant Women and Preterm Birth

IMPORTANCE

Preterm birth remains a leading cause of perinatal mortality and lifelong morbidity worldwide. The cause of most preterm births is unknown, although several infectious processes have been implicated.

OBJECTIVE

To assess whether human papillomavirus (HPV) infection, a frequent infection among women of childbearing age, is associated with preterm birth.

DESIGN, SETTING, AND PARTICIPANTS

The prospective HERITAGE cohort study was conducted at 3 academic hospitals in Montreal, Québec, Canada, among 899 pregnant women recruited between November 8, 2010, and October 16, 2016. Follow-up was completed on June 15, 2017. Statistical analysis was conducted from February 6, 2020, to January 21, 2021.

EXPOSURES

Vaginal HPV DNA detection in the first and third trimesters of pregnancy and placental HPV infection.

MAIN OUTCOMES AND MEASURES

The main outcome was preterm birth (defined as a live birth or stillbirth between 20 weeks and 0 days and 36 weeks and 6 days of gestation). The association between HPV DNA detection and preterm birth was measured using logistic regression. Odds ratios (ORs) and 95% CIs were adjusted by inverse probability of treatment weights of the propensity score.

RESULTS

The study included 899 women (mean [SD] age, 31.3 [4.6] years [range, 19-47 years]) with singleton pregnancies. A total of 378 women (42.0%) had HPV DNA detected in vaginal samples collected during the first trimester, and it was detected in 91 of 819 placentas (11.1%) at delivery. Fifty-five participants experienced preterm birth (38 spontaneous and 17 medically indicated). Persistent vaginal HPV-16/18 detection was significantly associated with all preterm births (adjusted OR [aOR], 3.72; 95% CI, 1.47-9.39) and spontaneous preterm births (aOR, 3.32; 95% CI, 1.13-9.80), as was placental HPV infection (all preterm births: aOR, 2.53; 95% CI, 1.06-6.03; spontaneous preterm births: aOR, 2.92; 95% CI, 1.09-7.81). Results were similar when restricting the analysis to participants without a history of cervical intraepithelial neoplasia treatment.

CONCLUSIONS AND RELEVANCE

The study's results suggest that persistent HPV-16/18 infection is associated with an increased risk of preterm birth, independent of cervical treatment. Future studies should investigate the association of HPV vaccination and vaccination programs with the risk of preterm birth.

Human papillomavirus (HPV) in pregnancy - An update

Human papilloma viruses (HPV) are small epitheliotropic DNA viruses, of which there are 200 genotypes, 40 of which are known to cause genital infections and are also oncogenic. HPV is the most common sexually transmitted infection. Clinical features vary from asymptomatic (identified at routine cervical cancer screening) to large lesions on the vulva, vagina, cervix and some extragenital sites. Its prevalence in pregnancy varies from 5.5% to 65% depending on age, geography and gestational age (increasing with gestational age). Infection in pregnancy has been associated with adverse outcomes such as spontaneous miscarriage, preterm birth, placental abnormalities and fetal growth restriction. However, the evidence for these adverse outcomes is varied. Besides being oncogenic (and thus associated with cancer of the cervix in pregnancy), vertical transmission to the fetus/neonate can cause neonatal infections, especially juvenile-onset recurrent oral and respiratory papillomatosis (JORRP). Where there are very large lesions on the vulva, delivery may be obstructed. Diagnosis in pregnancy is mainly by viral PCR or from the clinical appearance of the characteristic lesions on the vulva. Treatment is local by either surgical or laser excision or application of trichloroacetic acid. Podophyllin/podophyllotoxin is contraindicated in pregnancy. HPV Infection is not an indication for caesarean delivery as this has not been shown to prevent vertical transmission. For those diagnosed at routine cervical cancer screening, management should follow guidelines for cervical cancer screening in pregnancy. Vaccination is currently not recommended for pregnant women, although studies on those inadvertently vaccinated in pregnancy have not shown any adverse effects on either the fetus or mother.

Human papilloma virus infection and miscarriage: is there an association?

Human papilloma virus (HPV) infection is the most common viral infection of the reproductive tract. HPV infection is more prevalent in pregnant than in age-matched non-pregnant women and its prevalence increases as pregnancy progresses. A number of reports evaluated the role of HPV infection in miscarriages. In the present review, we summarize the existing evidence regarding the association between HPV infection and miscarriage. It is still unclear whether HPV infection is associated with increased risk for miscarriage. Studies in the field yielded conflicting findings and their conclusions are limited by a small sample size and/or methodological limitations. On the other hand, preclinical data support a role of HPV infection in placental dysfunction. Given the high prevalence of HPV infection and the possibility that vaccination against HPV might protect against miscarriage, more studies are needed to elucidate whether this common infection is associated with increased risk for miscarriage.

Maternal human papillomavirus infections at mid-pregnancy and delivery in a Scandinavian mother-child cohort study

OBJECTIVES

Human papillomavirus (HPV) infections are common, especially during women's reproductive years, with unclear obstetrical impact. This study aimed to identify HPV prevalence at mid-gestation and delivery, type-specific persistence from mid-gestation to delivery, and risk factors for HPV infection and persistence.

METHODS

In 757 women from a Scandinavian prospective mother-child cohort, HPV was analyzed in first-void urine samples at mid-gestation and delivery. We used Seegene Anyplex II HPV28 PCR assay for genotyping and semi-quantifying 28 genital HPV genotypes, including 12 high-risk HPVs (HR-HPV). Socio-demographic and health data were collected through e-questionnaires.

RESULTS

Any-HPV genotype (any of 28 assessed) was detected in 38% of the study cohort at mid-gestation and 28% at delivery, and HR-HPVs in 24% and 16%, respectively. The most prevalent genotype was HPV16: 6% at mid-gestation and 4% at delivery. Persistence of Any-HPV genotype was 52%, as was HR-HPV genotype-specific persistence. A short pre-conception relationship with the child's father and alcohol intake during pregnancy increased HPV infection risk at both time points. Low viral load at mid-gestation was associated with clearance of HPV infections at delivery.

CONCLUSION

HPV prevalence was higher at mid-gestation compared with delivery, and low viral load was associated with clearance of HPV at delivery.

Central role of the placenta during viral infection: Immuno-competences and miRNA defensive responses

Pregnancy is a unique immunological condition in which an "immune-diplomatic" dialogue between trophoblasts and maternal immune cells is established to protect the fetus from rejection, to create a privileged environment in the uterus and to simultaneously be alert to any infectious challenge. The maternal-placental-fetal interface (MPFI) performs an essential role in this immunological defense. In this review, we will address the MPFI as an active immuno-mechanical barrier that protects against viral infections. We will describe the main viral infections affecting the placenta and trophoblasts and present their structure, mechanisms of immunocompetence and defensive responses to viral infections in pregnancy. In particular, we will analyze infection routes in the placenta and trophoblasts and the maternal-fetal outcomes in both. Finally, we will focus on the cellular targets of the antiviral microRNAs from the C19MC cluster, and their effects at both the intra- and extracellular level.

Genetic instability and anti-HPV immune response as drivers of infertility associated with HPV infection

Human papillomavirus (HPV) is a sexually transmitted infection common among men and women of reproductive age worldwide. HPV viruses are associated with epithelial lesions and cancers. HPV infections have been shown to be significantly associated with many adverse effects in reproductive function. Infection with HPVs, specifically of high-oncogenic risk types (HR HPVs), affects different stages of human reproduction, resulting in a series of adverse outcomes: 1) reduction of male fertility (male infertility), characterized by qualitative and quantitative semen alterations; 2) impairment of couple fertility with increase of blastocyst apoptosis and reduction of endometrial implantation of trophoblastic cells; 3) defects of embryos and fetal development, with increase of spontaneous abortion and spontaneous preterm birth. The actual molecular mechanism(s) by which HPV infection is involved remain unclear. HPV-associated infertility as Janus, has two faces: one reflecting anti-HPV immunity, and the other, direct pathogenic effects of HPVs, specifically, of HR HPVs on the infected/HPV-replicating cells. Adverse effects observed for HR HPVs differ depending on the genotype of infecting virus, reflecting differential response of the host immune system as well as functional differences between HPVs and their individual proteins/antigens, including their ability to induce genetic instability/DNA damage. Review summarizes HPV involvement in all reproductive stages, evaluate the adverse role(s) played by HPVs, and identifies mechanisms of viral pathogenicity, common as well as specific for each stage of the reproduction process.

Is the ZIKV Congenital Syndrome and Microcephaly Due to Syndemism with Latent Virus Coinfection?

The emergence of the Zika virus (ZIKV) mirrors its evolutionary nature and, thus, its ability to grow in diversity or complexity (i.e., related to genome, host response, environment changes, tropism, and pathogenicity), leading to it recently joining the circle of closed congenital pathogens. The causal relation of ZIKV to microcephaly is still a much-debated issue. The identification of outbreak foci being in certain endemic urban areas characterized by a high-density population emphasizes that mixed infections might spearhead the recent appearance of a wide range of diseases that were initially attributed to ZIKV. Globally, such coinfections may have both positive and negative effects on viral replication, tropism, host response, and the viral genome. In other words, the possibility of coinfection may necessitate revisiting what is considered to be known regarding the pathogenesis and epidemiology of ZIKV diseases. ZIKV viral coinfections are already being reported with other arboviruses (e.g., chikungunya virus (CHIKV) and dengue virus (DENV)) as well as congenital pathogens (e.g., human immunodeficiency virus (HIV) and cytomegalovirus (HCMV)). However, descriptions of human latent viruses and their impacts on ZIKV disease outcomes in hosts are currently lacking. This review proposes to select some interesting human latent viruses (i.e., herpes simplex virus 2 (HSV-2), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), human parvovirus B19 (B19V), and human papillomavirus (HPV)), whose virological features and co-exposition with ZIKV may provide evidence of the syndemism process, shedding some light on the emergence of the ZIKV-induced global congenital syndrome in South America.

Chronic villitis of unknown etiology: Investigations into viral pathogenesis

INTRODUCTION

Chronic villitis of unknown etiology (VUE) is a chronic inflammatory lesion of third trimester placenta, which contributes to major adverse obstetric outcomes. However, the inciting factors and mechanisms by which VUE contributes to adverse outcomes are poorly understood. This limits our ability to develop preventions or interventions. Our goals were to determine whether viruses can be detected in placental tissues with VUE and to determine whether gene expression profiles support an antiviral response.

METHODS

We extracted RNA and DNA from 20 placentas with high-grade chronic villitis and 20 control placentas without inflammation. Viruses were assessed using ViroCap viral nucleic acid enrichment coupled with metagenomic sequencing. RNA sequencing was used to evaluate the inflammatory gene expression profiles in each placenta.

RESULTS

We detected at least 1 virus in 50% of the samples tested. We found that herpesviruses, were found more frequently in cases compared with controls (P = 0.01). Antiviral pathways, including defense response to virus, interferon gamma response, and IFN alpha/beta response, were upregulated in cases. We observed two clusters of gene expression profiles in the VUE cases, suggesting multiple inflammatory profiles are associated with VUE.

DISCUSSION

These data support a viral etiology for some cases of VUE. Furthermore, gene expression profiles suggest the possibility of more than one cause or manifestation of VUE. Viral mechanisms should be explored as potential targets for prevention or intervention in VUE.

Association Between Maternal Human Papillomavirus Infection and Adverse Pregnancy Outcomes: Systematic Review and Meta-Analysis

BACKGROUND

Experimental studies provide evidence of the harmful effect of human papillomavirus (HPV) infection on pregnancy, but observational studies are inconclusive. We systematically assessed the association between HPV and adverse pregnancy outcomes.

METHODS

We searched electronic databases up to December 1, 2019. We included observational studies on the association between HPV and adverse pregnancy outcomes. We conducted a random-effect meta-analysis for each outcome and assessed heterogeneity between studies.

RESULTS

From 3034 citations, we included 38 studies and quantitatively synthesized 36 studies. Human papillomavirus was significantly associated with preterm birth (age-adjusted odds ratio [aOR], 1.50; 95% confidence interval [CI], 1.19-1.88), preterm premature rupture of membranes (aOR, 1.96; 95% CI, 1.11-3.45), premature rupture of membranes (aOR, 1.42; 95% CI, 1.08-1.86), intrauterine growth restriction (aOR, 1.17; 95% CI, 1.01-1.37), low birth weight (aOR, 1.91; 95% CI, 1.33-2.76), and fetal death (aOR, 2.23; 95% CI, 1.14-4.37). No significant association was found for spontaneous abortion (aOR, 1.14; 95% CI, 0.40-3.22) and pregnancy-induced hypertensive disorders (aOR, 1.24; 95% CI, 0.80-1.92). Most of the studies were of moderate or low quality, and substantial between-studies heterogeneity remained unexplained.

CONCLUSIONS

We found a consistent and significant association between HPV and preterm birth and preterm premature rupture of membranes. Human papillomavirus may also be associated with intrauterine growth restriction, low birth weight, and fetal death, but findings are limited by suboptimal control of biases.

Has Human Papillomavirus (HPV) Vaccination Prevented Adverse Pregnancy Outcomes? Population-Level Analysis After 8 Years of a National HPV Vaccination Program in Australia

Background

Human papillomavirus (HPV) infection, and its sequelae of precancerous cervical lesions and their subsequent treatment, have been linked with an increased risk of adverse pregnancy outcomes. Publicly funded HPV vaccination of female adolescents began in Australia in 2007 with initial catch-up to age 26 years.

Methods

Using data from the National Perinatal Data Collection we compared rates of preterm births and small-for-gestational-age infants born in Australia 2000–2015. We used generalized linear models, assuming a Poisson distribution and log link function, with single-year categories of infant birth year, maternal age, and age-specific HPV vaccination coverage as independent variables.

Results

In maternal cohorts with 60%–80% HPV vaccination coverage as achieved in Australia, there was a relative rate reduction of 3.2% (95% confidence interval, 1.1%–5.3%) in preterm births and 9.8% (8.2% to 11.4%) in small-for-gestational-age infants, after adjustment for infant’s birth year and maternal age.

Conclusion

This analysis provides provisional population-level evidence of a reduction in adverse pregnancy outcomes in cohorts of women offered HPV vaccination. Confounding by smoking or other variables and/or ecological analysis limitations, however, cannot be excluded. These findings indicate potential broader benefits of HPV vaccination than have been documented to date.

Villitis of unknown etiology and chronic deciduitis are not associated with human papilloma virus and enterovirus infection

Villitis of unknown etiology (VUE) and chronic deciduitis with plasma cells (CD) are supposed to be non infectious placental lesions caused by a pathologic immune reaction similar to a host versus graft mechanism. In some investigations, infection of human trophoblastic cells with human papilloma virus (HPV) has been described, and a relationship with miscarriage, preeclampsia, and chronic inflammatory placental lesions has been suspected. Infection with enterovirus, especially Coxsackievirus, has been observed in cases with spontaneous abortion and adverse perinatal outcome, respectively. We investigated 20 cases with VUE and 30 cases with chronic deciduitis with plasma cells. The placenta specimens were analyzed for expression of HPV capsid protein by immunohistochemistry, for presence of HPV DNA via polymerase chain reaction (PCR), and for presence of enterovirus mRNA using RT-PCR, respectively. VUE was associated with maternal diseases: atopic lesions in 21%, other autoimmune diseases in 15.5%, and obesity in 31.5%, respectively. Birth weight below the 10th percentile was detected in 63% of the cases with VUE. Chronic deciduitis was associated with preterm labor and preterm premature rupture of membranes (26%). Intrauterine fetal demise occurred in 5 cases with CD (18.5%). HPV DNA, HPV capsid protein, and enterovirus mRNA were not detected in all investigated VUE or CD cases. Our investigations show that a causal role for enterovirus and human papilloma virus in the development of VUE and CD is unlikely. Therefore, HPV vaccination is unlikely to reduce the incidence of VUE and CD in the future.

Innate Immune Cells and Toll-like Receptor-Dependent Responses at the Maternal-Fetal Interface

During pregnancy, the placenta, the mother and the fetus exploit several mechanisms in order to avoid fetal rejection and to maintain an immunotolerant environment throughout nine months. During this time, immune cells from the fetal and maternal compartments interact to provide an adequate defense in case of an infection and to promote a tolerogenic milieu for the fetus to develop peacefully. Trophoblasts and decidual cells, together with resident natural killer cells, dendritic cells, Hofbauer cells and other macrophages, among other cell types, contribute to the modulation of the uterine environment to sustain a successful pregnancy. In this review, the authors outlined some of the various roles that the innate immune system plays at the maternal-fetal interface. First, the cell populations that are recruited into gestational tissues and their immune mechanisms were examined. In the second part, the Toll-like receptor (TLR)-dependent immune responses at the maternal-fetal interface was summarized, in terms of their specific cytokine/chemokine/antimicrobial peptide expression profiles throughout pregnancy.

Human Papillomavirus (HPV) Infection in Early Pregnancy: Prevalence and Implications

Introduction

Young women (20-35 years) are at high risk of HPV infection, although the majority of the infections are asymptomatic and are cleared spontaneously by the host immune system. These are also the group of women who are sexually active and are in the population of pregnant women. During pregnancy, the changes in the hormonal milieu and immune response may favor persistence of HPV infection and may aid in transgenerational transmission thereby furthering the cancer risk. In the present study, we determined the prevalence of vaginal HPV infection in early pregnancy and attempted to relate with pregnancy outcome.

Material and Methods

Vaginal cytology samples were collected from the condoms used to cover the vaginal sonography probe during a routine first trimester visit to the hospital. All women were followed up throughout pregnancy and childbirth. Maternal and neonatal outcomes were recorded.

Results

We found a prevalence of HPV infection around 39.4% in our population. Interestingly all HPV positive women were infected with one or more high risk HPV viruses with an overlap of intermediate and low risk in 43% and 7.3%, respectively. Women with preterm prelabor rupture of membranes (PPROM) showed a statistically higher incidence in HPV positive (7.3%) group as compared to the HPV negative (3.2%) group.

Conclusion

The prevalence of genital HPV infection is high during pregnancy (around 40%) and was associated with higher incidence of PPROM.

Cervical human papillomavirus infection in women with preterm prelabor rupture of membranes

OBJECTIVE

To evaluate the association between cervical human papillomavirus (HPV) infection at the time of admission and the presence of microbial invasion of the amniotic cavity (MIAC) and intra-amniotic inflammation (IAI) in women with preterm prelabor rupture of membranes (PPROM) and to determine the association between cervical HPV infection and short-term neonatal morbidity.

METHODS

One hundred women with singleton pregnancies complicated by PPROM between the gestational ages of 24+0 and 36+6 weeks were included in the study. The presence of HPV DNA was evaluated in scraped cervical cells using polymerase chain reaction (PCR). Amniotic fluid samples were obtained by transabdominal amniocentesis.

RESULTS

The rate of cervical HPV infection in women with PPROM was 24%. The rates of MIAC and IAI were not different between women with cervical HPV infection and those without cervical HPV infection [MIAC: with HPV: 21% (5/24) vs. without HPV: 22% (17/76), p = 1.00; IAI: with HPV: 21% (5/24) vs. without HPV: 18% (14/76), p = 0.77]. There were no differences in the selected aspects of short-term neonatal morbidity between women with and without cervical HPV infection.

CONCLUSIONS

In women with PPROM, the presence of cervical HPV infection at the time of admission is not related to a higher risk of intra-amniotic infection-related and inflammatory complications or worse short-term neonatal outcomes.

HPV16 E6 and E7 Upregulate Interferon-Induced Antiviral Response Genes ISG15 and IFIT1 in Human Trophoblast Cells

Human papillomavirus (HPV) is suggested to infect trophoblasts in the placenta, and HPV infections are reported to be more prevalent in pregnancies with adverse outcomes. Results are however controversial, and studies investigating the molecular consequences of placental HPV infections are lacking. We studied HPV DNA localization in the placenta in cases of spontaneous abortion/spontaneous preterm delivery as well as in elective abortion/normal full-term delivery. Using in vitro assays, we investigated downstream effects of HPV16 E6 and E7 expression in trophoblast cells at the gene expression level in order to gain increased biological insight into the interaction between HPV and the cellular host. Fluorescent in situ hybridization (FISH), combined with fluorescent immunohistochemistry (FIHC) to target the trophoblast marker CK7 clearly showed, that HPV DNA resides within syncytiotrophoblast cells in the placenta. In vitro HPV16 E6 and E7-transfected trophoblasts were analyzed by RNA sequencing, and results were validated by reverse transcription real time polymerase chain reaction (RT-qPCR) for selected genes in cell lines, as well as in patient material. We show that HPV16 E6 and E7 upregulate interferon-induced antiviral response genes ISG15 and IFIT1 in a human trophoblast cell line two-days post-transfection. This is a response that is not observed when assessing the gene expression levels of the same genes in HPV16-positive placenta samples. Investigations on viral activity find that HPV16 E6 and E7 are not transcribed in patients, possibly suggesting that HPV16 syncytiotrophoblast infection may be latent. We conclude that HPV localizes to syncytiotrophoblast cells of the placenta, and that active expression of HPV16 E6 and E7 induce an immediate interferon-induced antiviral response in trophoblast cells, which is not present in HPV-positive placenta samples, suggesting latent infection.