Detection of intrauterine viral infection using the polymerase chain reaction

Adenoviral Infections in Neonates: A Case-Based Literature Review

Adenoviral infections in neonates are associated with high rates of mortality due to the lack of humoral immunity. A comprehensive search of published literature in PubMed, Google Scholar, and Science Direct electronic databases was conducted for case reports published between the years 1990 and 2021. The aim of our study is to investigate the risk factors, clinical manifestations, treatment, and outcomes of adenoviral infections in neonates. In our study, 36 cases were included. The most common type of infection was disseminated one (14/36, 38.8%), followed by adenoviral pneumonia (13/36, 36.1%). Cidofovir was administered in seven cases (19.4%), and death was reported in six of them. One preterm low birthweight neonate with disseminated adenoviral infection was treated with a combination of cidofovir, intravenous immune globulin, and haploidentical virus-specific T lymphocytes (VSTs) and survived. In this review, we found a statistically significant difference in the outcome based on the type of adenoviral infection (p=0.001). Disseminated infection and pneumonia are associated with the worst prognosis. In addition, mortality was observed to be higher in neonates with disseminated disease in contrast to neonates with localized infection (p=0.002). However, the antiviral treatment had no statistically significant effect on the mortality rate (p=0.137). There is a necessity for further investigation and randomized studies to validate the results of the present study.

Clinically relevant DNA viruses in pregnancy

Infections by DNA viruses during pregnancy are associated with increased health risks to both mother and fetus. Although not all DNA viruses are related to an increased risk of complications during pregnancy, several can directly infect the fetus and/or cause placental dysfunction. During NIPT analysis, the presence of viral DNA can be detected, theoretically allowing screening early in pregnancy. Although treatment options are currently limited, this might rapidly change in the near future. It is therefore important to be aware of the potential impact of these viruses on feto-maternal health. In this manuscript we provide a brief introduction into the most commonly detected DNA viruses in human cell-free DNA sequencing experiments and their pathogenic potential during pregnancy. This article is protected by copyright. All rights reserved.

The Vaginal Virome-Balancing Female Genital Tract Bacteriome, Mucosal Immunity, and Sexual and Reproductive Health Outcomes?

Besides bacteria, fungi, protists and archaea, the vaginal ecosystem also contains a range of prokaryote- and eukaryote-infecting viruses, which are collectively referred to as the "virome". Despite its well-described role in the gut and other environmental niches, the vaginal virome remains understudied. With a focus on sexual and reproductive health, we summarize the currently known components of the vaginal virome, its relationship with other constituents of the vaginal microbiota and its association with adverse health outcomes. While a range of eukaryote-infecting viruses has been described to be present in the female genital tract (FGT), few prokaryote-infecting viruses have been described. Literature suggests that various vaginal viruses interact with vaginal bacterial microbiota and host immunity and that any imbalance thereof may contribute to the risk of adverse reproductive health outcomes, including infertility and adverse birth outcomes. Current limitations of vaginal virome research include experimental and analytical constraints. Considering the vaginal virome may represent the missing link in our understanding of the relationship between FGT bacteria, mucosal immunity, and adverse sexual and reproductive health outcomes, future studies evaluating the vaginal microbiome and its population dynamics holistically will be important for understanding the role of the vaginal virome in balancing health and disease.

Alphatorquevirus is the most prevalent virus identified in blood from a matched maternal-infant preterm cohort

Objective: To determine the prevalence of virus in a previously uncharacterized matched maternal-infant preterm cohort and test if viral presence or viral load correlate with histologic chorioamnionitis, spontaneous preterm labor or pre-eclampsia.Study Design: Using qRT-PCR/qPCR we tested plasma or whole blood samples from 56 matched maternal and premature infant dyads for: adenovirus, anellovirus (alphatorquevirus and betatorquevirus), cytomegalovirus (CMV), Epstein-Barr virus (EBV), enterovirus, human herpesvirus 6 (HHV6), parechovirus, and parvovirus B19.Result: Viral detection was more common in maternal samples 29/56 (52%) than in cord blood from their infants (4/56 (7%)) (p ≤ .0001). No significant difference in viral load or viral prevalence was identified between pregnancies with and without histologic chorioamnionitis, spontaneous preterm labor or pre-eclampsia.Conclusion: Despite frequent detection of virus in maternal samples, virus was less frequently detected in the infants. Additionally, there was no association of presence or quantity of virus in maternal blood with histologic chorioamnionitis, spontaneous preterm labor or pre-eclampsia in this small, but well-defined cohort. Future studies are necessary to further characterize the role of virus in placental inflammatory states and pregnancy outcomes.

Amniotic fluid from healthy term pregnancies does not harbor a detectable microbial community

Recent studies have conflicting data regarding the presence of intra-amniotic microbiota. Viral communities are increasingly recognized as important although overlooked components of the human microbiota. It is unknown if the developing fetus is exposed to a community of viruses (virome). Given the debate over the existence of an intra-amniotic microbial community and the importance of understanding how the infant gut is populated, we characterized the virome and bacterial microbiota of amniotic fluid from 24 uncomplicated term pregnancies using next-generation sequencing methods. Contrary to expectations, the bacterial microbiota of amniotic fluid was indistinguishable from contamination controls. Viral reads were sparse in the amniotic fluid, and we found no evidence of a core viral community across samples.

Maternal infection and stress during pregnancy and depressive symptoms in adolescent offspring

Maternal infection during pregnancy has been linked to increased risk of offspring depression. Additionally, maternal stress during pregnancy has been consistently linked with adverse offspring outcomes associated with depression. Relatedly, stress has been associated with increased risk of infection; however no study has investigated stress-infection interactions during pregnancy and risk for offspring depression. Participants were drawn from the Child Health and Development Studies (CHDS), a prospective, longitudinal study that enrolled pregnant women from 1959 to 1966. Maternal health and birth outcome information were collected, as well as open-ended interviews about worrisome events during pregnancy. The present study included participants from a subsample of women whose offspring (n = 1711) completed self-reports of depressive symptoms during adolescence. Results indicated that maternal infection during only the second trimester was associated with higher scores on adolescent offspring depressive symptoms, while controlling for maternal education at birth, adolescent age, and maternal depressive symptoms at adolescence. Maternal experiences of daily stress during pregnancy moderated this association, such that mothers diagnosed with second trimester infection and who experienced daily stress had offspring with significantly higher depression scores than mothers of adolescents diagnosed with an infection alone. Findings have potential implications for prevention and intervention strategies.

Sterile and microbial-associated intra-amniotic inflammation in preterm prelabor rupture of membranes

OBJECTIVE

The objectives of this study were to: (1) determine the amniotic fluid (AF) microbiology of patients with preterm prelabor rupture of membranes (PROM); and (2) examine the relationship between intra-amniotic inflammation with and without microorganisms (sterile inflammation) and adverse pregnancy outcomes in patients with preterm PROM.

METHODS

AF samples obtained from 59 women with preterm PROM were analyzed using cultivation techniques (for aerobic and anaerobic bacteria as well as genital mycoplasmas) and with broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS). AF concentration of interleukin-6 (IL-6) was determined using ELISA. Results of both tests were correlated with AF IL-6 concentrations and the occurrence of adverse obstetrical/perinatal outcomes.

RESULTS

(1) PCR/ESI-MS, AF culture, and the combination of these two tests each identified microorganisms in 36% (21/59), 24% (14/59) and 41% (24/59) of women with preterm PROM, respectively; (2) the most frequent microorganisms found in the amniotic cavity were Sneathia species and Ureaplasma urealyticum; (3) the frequency of microbial-associated and sterile intra-amniotic inflammation was overall similar [ 29% (17/59)]: however, the prevalence of each differed according to the gestational age when PROM occurred; (4) the earlier the gestational age at preterm PROM, the higher the frequency of both microbial-associated and sterile intra-amniotic inflammation; (5) the intensity of the intra-amniotic inflammatory response against microorganisms is stronger when preterm PROM occurs early in pregnancy; and (6) the frequency of acute placental inflammation (histologic chorioamnionitis and/or funisitis) was significantly higher in patients with microbial-associated intra-amniotic inflammation than in those without intra-amniotic inflammation [93.3% (14/15) versus 38% (6/16); p = 0.001].

CONCLUSIONS

(1) The frequency of microorganisms in preterm PROM is 40% using both cultivation techniques and PCR/ESI-MS; (2) PCR/ESI-MS identified microorganisms in the AF of 50% more women with preterm PROM than AF culture; and (3) sterile intra-amniotic inflammation was present in 29% of these patients, and it was as or more common than microbial-associated intra-amniotic inflammation among those presenting after, but not before, 24 weeks of gestation.

Neonatal infection with species C adenoviruses confirmed in viable cord blood lymphocytes

Credible but conflicting reports address the frequency of prenatal infection by species C adenovirus. This question is important because these viruses persist in lymphoid cells and suppress double-stranded DNA-break repair. Consequently, prenatal adenovirus infections may generate the aberrant clones of lymphocytes that precede development of childhood acute lymphoblastic leukemia (ALL). The present study was designed to overcome technical limitations of prior work by processing cord blood lymphocytes within a day of collection, and by analyzing sufficient numbers of lymphocytes to detect adenovirus-containing cells at the lower limits determined by our previous studies of tonsil lymphocytes. By this approach, adenoviral DNA was identified in 19 of 517 (3.7%) samples, providing definitive evidence for the occurrence of prenatal infection with species C adenoviruses in a significant fraction of neonates predominantly of African American and Hispanic ancestry. Cord blood samples were also tested for the presence of the ETV6-RUNX1 translocation, the most common genetic abnormality in childhood ALL. Using a nested PCR assay, the ETV6-RUNX1 transcript was detected in four of 196 adenovirus-negative samples and one of 14 adenovirus-positive cord blood samples. These findings indicate that this method will be suitable for determining concordance between adenovirus infection and the leukemia-associated translocations in newborns.

A novel molecular microbiologic technique for the rapid diagnosis of microbial invasion of the amniotic cavity and intra-amniotic infection in preterm labor with intact membranes

PROBLEM

The diagnosis of microbial invasion of the amniotic cavity (MIAC) has been traditionally performed using traditional cultivation techniques, which require growth of microorganisms in the laboratory. Shortcomings of culture methods include the time required (days) for identification of microorganisms, and that many microbes involved in the genesis of human diseases are difficult to culture. A novel technique combines broad-range real-time polymerase chain reaction with electrospray ionization time-of-flight mass spectrometry (PCR/ESI-MS) to identify and quantify genomic material from bacteria and viruses.

METHOD OF STUDY

AF samples obtained by transabdominal amniocentesis from 142 women with preterm labor and intact membranes (PTL) were analyzed using cultivation techniques (aerobic, anaerobic, and genital mycoplasmas) as well as PCR/ESI-MS. The prevalence and relative magnitude of intra-amniotic inflammation [AF interleukin 6 (IL-6) concentration ≥ 2.6 ng/mL], acute histologic chorioamnionitis, spontaneous preterm delivery, and perinatal mortality were examined.

RESULTS

(i) The prevalence of MIAC in patients with PTL was 7% using standard cultivation techniques and 12% using PCR/ESI-MS; (ii) seven of ten patients with positive AF culture also had positive PCR/ESI-MS [≥17 genome equivalents per PCR reaction well (GE/well)]; (iii) patients with positive PCR/ESI-MS (≥17 GE/well) and negative AF cultures had significantly higher rates of intra-amniotic inflammation and acute histologic chorioamnionitis, a shorter interval to delivery [median (interquartile range-IQR)], and offspring at higher risk of perinatal mortality, than women with both tests negative [90% (9/10) versus 32% (39/122) OR: 5.6; 95% CI: 1.4-22; (P < 0.001); 70% (7/10) versus 35% (39/112); (P = 0.04); 1 (IQR: <1-2) days versus 25 (IQR: 5-51) days; (P = 0.002), respectively]; (iv) there were no significant differences in these outcomes between patients with positive PCR/ESI-MS (≥17 GE/well) who had negative AF cultures and those with positive AF cultures; and (v) PCR/ESI-MS detected genomic material from viruses in two patients (1.4%).

CONCLUSION

(i) Rapid diagnosis of intra-amniotic infection is possible using PCR/ESI-MS; (ii) the combined use of biomarkers of inflammation and PCR/ESI-MS allows for the identification of specific bacteria and viruses in women with preterm labor and intra-amniotic infection; and (iii) this approach may allow for administration of timely and specific interventions to reduce morbidity attributed to infection-induced preterm birth.

Intrauterine infection with parvovirus B19 and CMV: implications in early and late gestation fetal demise

In utero viral infections have been associated with an adverse pregnancy outcome and may have a causative role in the unexplained fetal death file. Parvovirus B19 and cytomegalovirus are among the most common pathogens implicated in fetal loss cases. Parvovirus B19 has been reported to account for cases of spontaneous abortions, intrauterine fetal death and nonimmune hydrops fetalis, whereas cytomegalovirus accounts for nonimmune hydrops fetalis, intrauterine growth retardation and congenital anomalies. This review aims to summarize the current literature in an attempt to underline the need for routine screening, close follow-up and prevention. A better understanding of the pathogenetic mechanisms of viral infections during the crucial time of organogenesis, along with early detection, may contribute to the reduction in stillbirth rate.

Herpes simplex virus: prevalence in placental tissue and incidence in neonatal cord blood samples

Herpes simplex virus (HSV) infection is one of the most prevalent infectious diseases worldwide, with HSV-2 being primarily associated with genital infections. HSV-2 is believed to account for the majority of cases of neonatal herpes, which may cause diverse of complications in infected newborns. The present study sought to estimate the prevalence of HSV-2 in placental tissue samples and the incidence of HSV-2 in the umbilical cord blood of newborn infants. Placental tissue samples from 201 women (maternal-side and fetal-side = 402 specimens) and 184 neonatal cord blood samples, all collected at the obstetric ward of a University hospital were studied. HSV-2 was detected by means of nested PCR. The prevalence of HSV-2 in placental samples was 9.0% (n = 18), and the incidence of neonatal HSV-2 infection was 1.1% (n = 2). All HSV-2-positive patients were asymptomatic at the time of delivery and none reported genital herpes. Women with a time between rupture of membranes and delivery of ≥360 min had an approximately fourfold risk of HSV-2 infection in the placental tissue (95% CI 0.93-5.66, P = 0.01). These results suggest that HSV-2 is present in the placenta of asymptomatic women and that a risk of transmission to the neonate exists. New strategies must be implemented for the management of asymptomatic patients who are capable of transmitting the virus to the newborn.

Preterm prelabor rupture of membranes (PPROM) is not associated with presence of viral genomes in the amniotic fluid

BACKGROUND

The role of viral infections in preterm prelabor rupture of the membranes (PPROM) is not established. Studies on the presence of viral genomes in the amniotic fluid (AF) collected in pregnancies complicated by PPROM show contradictory outcomes.

OBJECTIVES

To investigate AF samples of PPROM pregnancies for the presence of viral genomes.

STUDY DESIGN

AF samples from patients with PPROM were collected during a 4-year (2008-2012) observational study. 174 women were included with selection criteria of singleton pregnancy, PPROM, and maternal age of 18 years and above. PCR was used for detection of human cytomegalovirus (HCMV), herpes simplex virus (HSV), parvovirus B19, human adenoviruses (HAdV), enteroviruses (EV) and human parechovirus (HPeV). The selection of these viral targets was based on literature regarding screening of AF for presence of viral genomes.

RESULTS

Only a single sample was positive out of the 174 tested AFs, HCMV DNA was detected.

CONCLUSIONS

PPROM is not associated with active viral infections.

Seminal shedding of human herpesviruses

Most of the human herpesviruses can be found in semen, although the reported prevalence varies considerably between individual studies. The frequent presence of herpesvirus in semen raises the question whether sexual transmission of the virus could have an impact on human reproduction. Only few studies have associated seminal shedding of herpesviruses with impaired sperm quality, reduced fertility, or reduced chances of pregnancy, whereas most studies fail to find an association. Taken together, no firm evidence is so far linking the presence of herpesviruses in semen to impaired human reproduction.

[Adenovirus infections in immunocompromised patients]

Human adenoviruses function as genetic models and vectors for gene therapy. Upper respiratory, gastrointestinal or ocular infections usually have mild course without any major complication in immunocompetent individuals. However, reactivation from latency in immunocompromised patients may lead to death. Depending on the underlying diseases, different adenovirus serotypes damage different organs. In children with severe combined immunodeficiency syndrome, serotypes of species A and C induce lung, liver or bladder inflammation. Paediatric hematopoietic stem cell transplantation is frequently followed by serotype 31-induced pneumonia, enteritis, cystitis. B serotypes can destroy transplanted organs. In AIDS patients, D and novel F serotypes cause enteritis. Recombinants of B serotypes induce urinary tract infections. Progression of lymphomas, tumours, and systemic lupus erythematosus might be facilitated by immunosuppressive effects of adenoviruses. As far as the diagnostic work-up of adenoviruses, detection of viral DNA and virus copy number is predictive, while serology testing is quite unreliable. For treatment, cidofovir derivates, ribavirin, ganciclovir, vidarabine and microRNA have been used.

Viral invasion of the amniotic cavity (VIAC) in the midtrimester of pregnancy

INTRODUCTION

The prevalence of viral infections in the amniotic fluid (AF) has not yet been ascertained. The aim of this study was to determine the prevalence of specific viral nucleic acids in the AF and its relationship to pregnancy outcome.

STUDY DESIGN

From a cohort of 847 consecutive women undergoing midtrimester amniocentesis, 729 cases were included in this study after exclusion of documented fetal anomalies, chromosomal abnormalities, unavailability of AF specimens and clinical outcomes. AF specimens were tested by quantitative real-time PCR for the presence of genome sequences of the following viruses: adenoviruses, herpes simplex virus (HSV), varicella zoster virus (VZV), human herpesvirus 6 (HHV6), human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), parvovirus B19 and enteroviruses. Viral nucleic acid testing was also performed in maternal blood and cord blood in the population of women in whom AF was positive for viruses and in a control group of 29 women with AF negative for viral nucleic acids. The relationship between the presence of viruses and pregnancy and neonatal outcome was examined. The correlation between the presence of nucleic acids of viruses in the AF and the concentration of the cytokine interleukin-6 (IL-6) and the T cell chemokine CXCL-10 (or IP-10) in AF and maternal blood were analyzed.

RESULTS

Viral genome sequences were found in 16 of 729 (2.2%) AF samples. HHV6 was the most commonly detected virus (7 cases, 1.0%), followed by HCMV (6 cases, 0.8%), parvovirus B19 (2 cases, 0.3%) and EBV (1 case, 0.1%), while HSV, VZV, enteroviruses and adenoviruses were not found in this cohort. Corresponding viral DNA was also detected in maternal blood of six out of seven women with HHV6-positive AF and in the umbilical cord plasma, which was available in one case. In contrast, viral DNA was not detected in maternal blood of women with AF positive for parvovirus B19, HCMV, EBV or of women with AF negative for viruses. HHV6 genome copy number in AF and maternal blood was consistent with genomic integration of viral DNA and genetic infection in all women. There was no significant difference in the AF concentration of IL-6 and IP-10 between patients with and without VIAC. However, for HCMV, there was a significant relationship between viral copy number and IP-10 concentration in maternal blood and AF. The group of women with AF positive for viral DNA delivered at term healthy neonates without complications in 14 out of 16 cases. In one case of HHV6 infection in the AF, the patient developed gestational hypertension at term, and in another case of HHV6 infection in the AF, the patient delivered at 33 weeks after preterm premature rupture of membranes (PPROM).

CONCLUSION

Viral nucleic acids are detectable in 2.2% of AF samples obtained from asymptomatic women in the midtrimester. HHV6 was the most frequently detected virus in AF. Adenoviruses were not detected. Vertical transmission of HHV6 was demonstrated in one case.

Midtrimester amniotic fluid concentrations of interleukin-6 and interferon-gamma-inducible protein-10: evidence for heterogeneity of intra-amniotic inflammation and associations with spontaneous early (<32 weeks) and late (>32 weeks) preterm delivery

INTRODUCTION

Intra-amniotic inflammation is traditionally defined as an elevation of amniotic fluid interleukin (IL)-6. Previous case control studies have suggested an association between an elevated midtrimester amniotic fluid IL-6 and preterm delivery, although such an association has been recently challenged. Intra-amniotic inflammation can also be defined by an elevation of the T-cell chemokine, Interferon-gamma-inducible protein (IP)-10. An elevation in amniotic fluid IP-10 has been associated with chronic chorioamnionitis, a lesion frequently found in late spontaneous preterm birth and fetal death. In contrast, an elevation in amniotic fluid IL-6 is typically associated with acute chorioamnionitis and funisitis. This study was conducted to examine the relationship between an elevation in amniotic fluid IL-6 in the midtrimester and preterm delivery at or before 32 weeks of gestation, and the amniotic fluid concentration of IP-10 and preterm delivery after 32 weeks of gestation.

MATERIALS AND METHODS

This cohort study included 847 consecutive women undergoing genetic midtrimester amniocentesis; in 796 cases, amniotic fluid and pregnancy outcome was available for study after exclusion of abnormal karyotype and/or fetal congenital anomalies. Spontaneous preterm delivery was defined as early (≤32 weeks) or late (after 32 completed weeks of pregnancy). The amniotic fluid and maternal blood concentrations of IL-6 and IP-10 were measured by specific immunoassays.

RESULTS

1) The prevalence of preterm delivery was 8.3% (66/796), while those of early and late spontaneous preterm delivery were 1.5% (n=12), and 4.5% (n=36), respectively; 2) patients who had a spontaneous preterm delivery after 32 weeks of gestation had a higher median amniotic fluid IP-10 concentration than those who delivered at term [median 713 pg/mL, inter-quartile range (IQR) 509-1427 pg/mL vs. median 589 pg/mL, IQR 402-953 pg/mL; P=0.006] and an elevation of amniotic fluid IP-10 concentration above 502 pg/mL (derived from an ROC curve) was associated with late spontaneous preterm delivery [odds ratio 3.9 (95% CI 1.6-9.9)]; 3) patients who had a spontaneous preterm delivery ≤32 weeks of gestation had a higher median amniotic fluid IL-6 concentration than those who delivered at term [median 2052 pg/mL, IQR 435-3015 pg/mL vs. median 414 pg/mL, IQR 209-930 pg/mL; P=0.006], and an elevated amniotic fluid IL-6 concentration above 1740 pg/mL (derived from an ROC curve) was associated with early spontaneous preterm delivery [odds ratio 9.5 (95% CI 2.9-31.1)]; 4) subclinical intra-amniotic inflammation, defined as an elevation of IL-6 (≥2.9 ng/mL) or IP-10 (≥2.2 ng/mL) concentration above the 95th percentile of patients who had uncomplicated term delivery (n=652 for IL-6 and n=633 for IP-10), was observed in 6.3% (50/796) and 5.8% (45/770) of cases, respectively. Although each type of inflammation is a risk factor for spontaneous preterm delivery, many patients had a term delivery without complication; 5) the amniotic fluid in the midtrimester did not contain microorganisms detectable with cultivation techniques.

CONCLUSIONS

INTRA-amniotic inflammation is heterogeneous. Some patients have elevated amniotic fluid concentrations of IL-6, and are at risk for spontaneous preterm delivery before 32 weeks of gestation, while others have an elevated IP-10 (a chemotactic T-cell chemokine) and such patients are at risk for spontaneous preterm delivery after 32 weeks of gestation. A fraction of patients have subclinical intra-amniotic inflammation and deliver at term. The clinical significance of this condition remains to be determined.

When are amniotic fluid viral PCR studies indicated in prenatal diagnosis?

OBJECTIVE

To determine which prenatal ultrasound findings indicate the need to also obtain PCR studies for viral genome in women undergoing midtrimester amniocentesis.

METHODS

This was a retrospective observational study on women that underwent amniotic fluid karyotyping and viral PCR testing for history or ultrasound based indication. Amniotic fluid was tested for adenovirus, cytomegalovirus, respiratory syncytial virus, enterovirus, Epstein-Barr virus, and parvovirus B19 using multiplex PCR study with multiple appropriate controls. Ultrasound findings were coded as normal or abnormal with 34 categories of ultrasound abnormality stratified into 18 subgroups. Relationships between these subgroups and karyotype/PCR results were tested by Pearson chi-square method or Fisher's exact test and overall logistic regression analysis.

RESULTS

Amniotic fluid samples from 1191 patients were obtained for the study. Abnormal karyotype was detected in 5.4% of cases (64/1191), and PCR was positive in 6.5% of cases (77/1191). Abnormal fetal ultrasonographic findings were observed in 28.4% of cases (338/1191). There was an association between intrauterine growth restriction, nonimmune hydrops fetalis, hand/foot anomalies or neural tube defects (NTDs), and PCR positivity. NTDs were associated with PCR positivity in fetuses with normal karyotype and nuchal thickening, cardiac or ventral wall defects were specifically associated with aneuploidy.

CONCLUSION

Amniotic fluid viral PCR testing should be considered for fetuses with intrauterine growth restriction, nonimmune hydrops fetalis, hand/foot anomalies, or NTDs. After aneuploidy is excluded, NTDs are associated with PCR positivity.

Human cytomegalovirus infection is detected frequently in stillbirths and is associated with fetal thrombotic vasculopathy

BACKGROUND

Human cytomegalovirus (CMV) is the most common congenital infection in developed countries and is a known cause of intrauterine fetal death. We examined CMV infection in stillbirths and the relationship with histopathological findings at autopsy.

METHODS

We collected liver, kidney, and placenta specimens from 130 stillbirths. CMV DNA and protein were detected using polymerase chain reaction and immunohistochemistry, along with routine autopsy of stillborn infants.

RESULTS

Overall, CMV DNA was detected in 15% of singleton, >20-week stillborn infants. CMV DNA was detected in kidney (9%), liver (11%), and placenta (5%) specimens, with 75% of infections confirmed by immunohistochemistry. Fetal thrombotic vasculopathy was the only histopathological abnormality associated with CMV infection (in 60% CMV-infected vs 28% uninfected stillbirths P = .010).

CONCLUSIONS

Stillbirth has multiple etiologies. However, the detection of CMV DNA in 15% of fetal tissues or placentae suggests a strong association between CMV infection in pregnancy and stillbirth. Molecular testing during postmortem investigation has an important role to determine the contribution of CMV infection.

Viral detection in hydrops fetalis, spontaneous abortion, and unexplained fetal death in utero

This study was undertaken to investigate the occurrence of viral infection in fetal death by examining tissues for the presence of DNA of several viral agents. Tissue specimens including heart, kidney, liver, lung, and placenta of 73 cases of fetal death were examined with 27 cases of elective termination of pregnancy as a control group. DNA extracted from these samples was tested for the presence of HSV, CMV, EBV, VZV, HHV-6, HHV-7, and PVB19. Viral DNA was found in one or more tissue samples from 25/73 cases (34%): CMV in 20, HSV in 5, parvovirus B19 in 5, HHV-7 in 3, and HHV-6 in 2. The presence of HHV-6 in fetal tissue has been reported rarely. No study so far has reported the detection of HHV-7 in fetal tissues with normal or adverse outcomes. Viral DNA was not found in any of the termination of pregnancy samples. Among the positive cases, eight had dual infection. One further case was positive for three viruses: HSV, CMV, and HHV-7. HHV-6 was the sole infectious agent in two cases, HHV-7 in one case, PVB19 in three, and CMV in ten cases. The finding of multiple viral DNA in 12% of the cases suggests the involvement of complex risk factors in cases of fetal loss. Although the cause of fetal death often includes other factors (e.g., chromosomal abnormalities) these data suggest the incidence of viral infective etiology may be higher than considered previously. However, larger studies are required to establish this link.

Acute non-immune hydrops fetalis caused by intrauterine echovirus infection

We present a case of non-immune hydrops fetalis presenting acutely in the third trimester caused by echovirus infection. The infant required intensive care for over 2 weeks.

Viral infection of the placenta leads to fetal inflammation and sensitization to bacterial products predisposing to preterm labor

Pandemics pose a more significant threat to pregnant women than to the nonpregnant population and may have a detrimental effect on the well being of the fetus. We have developed an animal model to evaluate the consequences of a viral infection characterized by lack of fetal transmission. The experiments described in this work show that viral infection of the placenta can elicit a fetal inflammatory response that, in turn, can cause organ damage and potentially downstream developmental deficiencies. Furthermore, we demonstrate that viral infection of the placenta may sensitize the pregnant mother to bacterial products and promote preterm labor. It is critical to take into consideration the fact that during pregnancy it is not only the maternal immune system responding, but also the fetal/placental unit. Our results further support the immunological role of the placenta and the fetus affecting the global response of the mother to microbial infections. This is relevant for making decisions associated with treatment and prevention during pandemics.

Viral epidemiologic shift in inflammatory heart disease: the increasing involvement of parvovirus B19 in the myocardium of pediatric cardiac transplant patients

BACKGROUND

Detection of viral genome in rejecting cardiac transplant patients has been reported, with coxsackievirus and adenovirus causing premature graft failure. Recently, parvovirus B19 (PVB19) genome in myocardial samples has been increasingly reported, but its role in cardiac pathology and effect on transplant graft survival are unknown. The objectives of this study were to determine if changes in the viruses identified in the myocardium represent an epidemiologic shift in viral myocardial disease and whether PVB19 adversely affects transplant graft survival.

METHODS

From September 2002 to December 2005, nested polymerase chain reaction was used to evaluate endomyocardial biopsy specimens for 99 children (aged 3 weeks-18 years) with heart transplants for the presence of viral genome. Cellular rejection was assessed by histology of specimens. Transplant coronary artery disease (TCAD) was diagnosed by coronary angiography or histopathology.

RESULTS

Specimens from 700 biopsies were evaluated from 99 patients; 121 specimens had viral genome, with 100 (82.6%) positive for PVB19, 24 for Epstein-Barr virus (EBV; 7 positive for PVB19 and EBV), 3 for CMV, and 1 for adenovirus. Presence of PVB19 genome did not correlate with rejection score, nor did a higher viral copy number. Early development of advanced TCAD (p < 0.001) occurred in 20 children with persistent PVB19 infection (> 6 months).

CONCLUSIONS

PVB19 is currently the predominant virus detected in heart transplant surveillance biopsy specimens, possibly representing an epidemiologic shift. Cellular rejection does not correlate with the presence or quantity of PVB19 genome in the myocardium, but children with chronic PVB19 infection have increased risk for earlier TCAD, supporting the hypothesis that PVB19 negatively affects graft survival.

Adenovirus DNA in Guthrie cards from children who develop acute lymphoblastic leukaemia (ALL)

BACKGROUND

In search of a proposed viral aetiology of childhood acute lymphoblastic leukaemia (ALL), the common species C adenoviruses were analysed in Guthrie cards.

METHODS

Guthrie cards from 243 children who later developed ALL and from 486 matched controls were collected and analysed by nested polymerase chain reaction for the presence of adenovirus DNA.

RESULTS

Adenovirus DNA was reliably detected from only two subjects, both of whom developed ALL.

CONCLUSION

Adenovirus DNA is detected in Guthrie card samples at too low a frequency to reveal an association between adenovirus and the development of leukaemia.

Perinatal outcomes after second trimester detection of amniotic fluid viral genome in asymptomatic patients

OBJECTIVE

Symptomatic fetal viral infection can affect placental and fetal development and may lead to non-immune hydrops or fetal death. All infections are not detectable by clinical history or ultrasound and a background positivity rate exists in asymptomatic patients. We investigated if intraamniotic presence of viral genome at the time of genetic amniocentesis in asypmtomatic patients affects perinatal outcome.

STUDY DESIGN

Six-hundred and eighty-six pregnancies referred for second trimester genetic amniocentesis with a normal ultrasound and fetal karyotype had amniotic fluid multiplex polymerase chain reaction for adeno-, cytomegalo-, Ebstein-Barr-, entero- and parvovirus. Forty asymptomatic patients that were positive for viral genome were matched 2:1 with negative controls. Perinatal outcomes were compared between these groups.

RESULTS

Pregnancy complications and perinatal outcomes were similar in the two groups.

CONCLUSION

Asymptomatic fetal viral infection at the time of second trimester amniocentesis does not increase the risk for adverse perinatal outcome.

Adenovirus detection in Guthrie cards from paediatric leukaemia cases and controls

Archived neonatal blood cards (Guthrie cards) from children who later contracted leukaemia and matched normal controls were assayed for adenovirus (AdV) C DNA content using two highly sensitive methods. In contrast to a previous report, AdV DNA was not detected at a higher frequency among neonates who later developed leukaemia, when compared with controls.

Viruses and other infections in stillbirth: what is the evidence and what should we be doing?

In Australia, as in other developed countries, approximately 40-50% of stillbirths are of unknown aetiology. Emerging evidence suggests stillbirths are often multifactorial. The absence of a known cause leads to uncertainty regarding the risk of recurrence, which can cause extreme anguish for parents that may manifest as guilt, anger or bewilderment. Further, clinical endeavours to prevent recurrences in future pregnancies are impaired by lack of a defined aetiology. Therefore, efforts to provide an aetiological diagnosis of stillbirth impact upon all aspects of care of the mother, and inform many parts of clinical decision making. Despite the magnitude of the problem, that is 7 stillbirths per 1000 births in Australia, diagnostic efforts to discover viral aetiologies are often minimal. Viruses and other difficult to culture organisms have been postulated as the aetiology of a number of obstetric and paediatric conditions of unknown cause, including stillbirth. Reasons forwarded for testing stillbirth cases for infectious agents are non-medical factors, including addressing all parents' need for diagnostic closure, identifying infectious agents as a sporadic cause of stillbirth to reassure parents and clinicians regarding risk for future pregnancies, and to reduce unnecessary testing. It is clear that viral agents including rubella, human cytomegalovirus (CMV), parvovirus B19, herpes simplex virus (HSV), lymphocytic choriomeningitis virus (LCMV), and varicella zoster virus (VZV) may cause intrauterine deaths. Evidence for many other agents is that minimal or asymptomatic infections also occur, so improved markers of adverse outcomes are needed. The role of other viruses and difficult-to-culture organisms in stillbirth is uncertain, and needs more research. However, testing stillborn babies for some viral agents remains a useful adjunct to histopathological and other examinations at autopsy. Modern molecular techniques such as multiplex PCR, allow searches for multiple agents. Now that such testing is available, it is important to assess the clinical usefulness of such testing.

Adenovirus DNA is detected at increased frequency in Guthrie cards from children who develop acute lymphoblastic leukaemia

Epidemiological evidence suggests that childhood acute lymphoblastic leukaemia (ALL) may be initiated by an in infection in utero. Adenovirus DNA was detected in 13 of 49 neonatal blood spots from ALL patients but only in 3 of 47 controls (P=0.012) suggesting a correlation between prenatal adenovirus infection and the development of ALL

The role of inflammation and infection in preterm birth

Inflammation has been implicated in the mechanisms responsible for preterm and term parturition, as well as fetal injury. Out of all of the suspected causes of preterm labor and delivery, infection and/or inflammation is the only pathological process for which both a firm causal link with preterm birth has been established and a molecular pathophysiology defined. Inflammation has also been implicated in the mechanism of spontaneous parturition at term. Most cases of histopathological inflammation and histological chorioamnionitis, both in preterm and term labor, are sub-clinical in nature. The isolation of bacteria in the amniotic fluid, known as microbial invasion of the amniotic cavity, is a pathological finding; the frequency of which is dependent upon the clinical presentation and gestational age. This article reviews the role of inflammation in preterm and term parturition.

Inflammation in preterm and term labour and delivery

Inflammation has been implicated in the mechanisms responsible for preterm and term parturition, as well as fetal injury. Out of all of the suspected causes of preterm labour and delivery, infection and/or inflammation is the only pathological process for which both a firm causal link with preterm birth has been established and a molecular pathophysiology defined. Inflammation has also been implicated in the mechanism of spontaneous parturition at term. Most cases of histopathological inflammation and histological chorioamnionitis, both in preterm and term labour, are sub-clinical in nature. The isolation of bacteria in the amniotic fluid, known as microbial invasion of the amniotic cavity, is a pathological finding; the frequency of which is dependent upon the clinical presentation and gestational age. There is a window of time during which it may be possible to detect a 'molecular signature of inflammation' by analysis of the transcriptome before histological evidence is observed. This article reviews the role of inflammation in preterm and term parturition. It is possible that modulation of inflammation using anti-inflammatory cytokines, corticoids, antioxidants and/or other factors may complement antibiotic therapy and limit fetal injury.

Correlates of placental infection with cytomegalovirus, parvovirus B19 or human herpes virus 7

Vertical transmission of viruses is an important cause of morbidity in the fetus and neonate. Placental viral infection indicates risk of vertical transmission, but not always transmission to, or disease of the fetus. Specimens from mothers and babies from three groups-two prospective and one retrospective cohort-were tested for pathogens of teratogenic potential using multiplex PCR. Placental infection was present in 13% of the 105 samples collected. Assessment of the prospective cohorts showed cytomegalovirus (CMV) detected in 4% of placentae from unselected women, parvovirus B19 in 1% and Ureaplasma parvum in 1% of placentae. In a retrospective cohort of women at high risk of transmitting congenital infection due to seroconversion during pregnancy, miscarriage or stillbirth, CMV was detected in 64% and human herpes virus type 7 in 9% of placentae. Of 14 PCR-positive placentae, two were associated with the birth of a living symptomatic infant, two with stillbirth, one with miscarriage, and two with elective terminations of pregnancy. Directed laboratory assessment of women at high risk of transmitting congenital infection, on the basis of clinical or laboratory markers, is important for accurate diagnosis of adverse outcomes of pregnancy. However, routine screening for viruses in the placentae from women with a low-risk serological profile for transmitting congenital infection is unlikely to result in significant numbers of additional diagnoses and is confounded by inadequacy of current diagnostic methods. The major pathogen detected in all cases of placental infection associated with fetal death was human CMV.

Inflammatory cardiomyopathy: there is a specific matrix destruction in the course of the disease

Cardiomyopathies are responsible for a high proportion of cases of congestive heart failure and sudden death, as well as for the need for transplantation. Understanding of the causes of these disorders has been sought in earnest over the past decade. We hypothesized that DCM is a disease of the cytoskeleton/sarcolemma, which affects the sarcomere. Evaluation of the sarcolemma in DCM and other forms of systolic heart failure demonstrates membrane disruption; and, secondarily, the extracellular matrix architecture is also affected. Disruption of the links from the sarcolemma to ECM at the dystrophin C-terminus and those to the sarcomere and nucleus via N-terminal dystrophin interactions could lead to a "domino effect" disruption of systolic function and development of arrhythmias. We also have suggested that dystrophin mutations play a role in idiopathic DCM in males. The T-cap/MLP/alpha-actinin/titin complex appears to stabilize Z-disc function via mechanical stretch sensing. Loss of elasticity results in the primary defect in the endogenous cardiac muscle stretch sensor machinery. The over-stretching of individual myocytes leads to activation of cell death pathways, at a time when stretch-regulated survival cues are diminished due to defective stretch sensing, leading to progression of heart failure. Genetic DCM and the acquired disorder viral myocarditis have the same clinical features including heart failure, arrhythmias, and conduction block, and also similar mechanisms of disease based on the proteins targeted. In dilated cardiomyopathy, the process of progressive ventricular dilation and changes of the shape of the ventricle to a more spherical shape, associated with changes in ventricular function and/or hypertrophy, occurs without known initiating disturbance. In those cases in which resolution of cardiac dysfunction does not occur, chronic DCM results. It has been unclear what the underlying etiology of this long-term sequela could be, but viral persistence and autoimmunity have been widely speculated.

Detection of viral deoxyribonucleic acid in amniotic fluid: association with fetal malformation and pregnancy abnormalities

OBJECTIVE

To first test the hypothesis that the presence of viral nucleic acid in amniotic fluid (AF) is associated with an abnormal pregnancy outcome, and second, to determine if the overall rate of polymerase chain reaction (PCR) positivity and the distribution of virus types vary geographically.

STUDY DESIGN

Cytomegalovirus (CMV), parvovirus B19, adenovirus, enterovirus, herpes simplex virus, Epstein-Barr virus, and respiratory syncytial virus nucleic acids were sought in 423 AF samples obtained for clinical indications: 284 from the East Coast (EC) and 139 from the Midwest (MW).

RESULTS

Gestational age at sampling was 19.1 weeks for EC and 20.1 weeks for MW. 13.5% of karyotypically normal singleton pregnancies (57/423) had a positive AF PCR. 11% of AF PCR from the EC while 18% of AF PCR from the MW were positive (p = 0.06). The most commonly detected viruses were adenovirus (77%), enterovirus (12%), and CMV and parvovirus B19 (5% each). Twenty-four percent of sonographically abnormal pregnancies (33/136) had a positive AF PCR compared to only 8.4% (24/287) of normal pregnancies (p < 0.001).

CONCLUSION

A positive AF PCR is associated with an increased rate of fetal structural malformations, intrauterine growth restriction, hydrops and other fetal abnormalities. There were no significant geographic differences in the incidence of AF viral PCR positivity.

Detection of parvovirus B19, cytomegalovirus and enterovirus infections in cases of intrauterine fetal death

AIMS

Maternal infections with parvovirus B19, cytomegalovirus (CMV) and enterovirus have been associated with intrauterine fetal death (IUFD), but the incidence of these infections is not clear. This prospective study was conducted to estimate this incidence.

METHODS

A prospective study of 38 months was conducted on cases of IUFD referred to Huddinge University Hospital, Stockholm, Sweden. Placental biopsies, fetal blood and amniotic fluid were collected from cases of IUFD (n=52). Placental biopsies from normal pregnancies at term (n=53) were used as controls. These tissues were examined for parvovirus B19 DNA, CMV DNA and enterovirus RNA using polymerase chain reaction (PCR). Maternal viral serology was measured in 46 cases and virus isolation for enterovirus in maternal stool samples was performed in 31 cases.

RESULTS

Viral nucleic acid was recovered in at least one tissue sample from six cases of fetal death (parvovirus B19 in two cases, CMV in three and enterovirus in one), while all placental biopsies from controls were found negative. Serological signs of primary maternal infection were found in two of the cases, and virus isolation for enterovirus was negative in all samples examined.

CONCLUSION

Parvovirus B19, CMV and enterovirus may be considered as etiologic agents in cases of fetal death. PCR on placental and/or fetal tissue improves diagnostic accuracy for these infections.

Is adenovirus a fetal pathogen?

OBJECTIVES

The purpose of this study was to test the relationship between adenovirus genetic material in the amniotic fluid and adverse pregnancy outcome.

STUDY DESIGN

This was a prospective, observational study of women who were referred in the second trimester of gestation for either genetic amniocentesis or evaluation of fetal malformation. A 2-mL aliquot of amniotic fluid was subjected to multiplex polymerase chain reaction for a panel of viruses that included adenovirus and human genome controls. Fetuses with an abnormal karyotype were excluded from analysis.

RESULTS

The prevalence of adenovirus was similar in normal (39/652) and anomalous fetuses (23/364; chi(2) test, P=.376). There was significant seasonal variation in the prevalence in both normal and anomalous fetuses (chi(2) exact test, P<.001), but no significant difference between groups. The monthly proportion of patients who underwent amniocentesis remained constant throughout the year (mean, 8.3%; chi(2) test, P=.67). Central nervous system anomalies and echogenic liver foci were significantly more common among fetuses with positive amniotic fluid polymerase chain reaction results for adenovirus (P<.005, respectively).

CONCLUSION

Adenovirus is found in a similar prevalence and seasonal variation in sonographically normal and abnormal pregnancies. Although a specific fetal presentation was not identified, echogenic liver lesions with or without hydrops and neural tube defects were significantly more common in the presence of adenovirus. The significance of these findings deserves further study.

Detection of viruses in myocardial tissues by polymerase chain reaction. evidence of adenovirus as a common cause of myocarditis in children and adults

OBJECTIVES

The purpose of this study was to analyze cardiac tissue and blood for viral genomes using polymerase chain reaction (PCR) to define the common viral etiologies of myocarditis by age group.

BACKGROUND

Enteroviruses are considered the most common cause of myocarditis at all ages. Diagnosis relies on viral cultures, serology, and cardiac histology, which lack sensitivity, as well as PCR. However, in many cases enteroviruses are not detected.

METHODS

Cardiac samples were obtained for PCR analysis from patients with myocarditis (n = 624) and dilated cardiomyopathy (DCM) (n = 149). Patients were analyzed by age group, including neonates (n = 116), infants (n = 191), toddlers (n = 87), children (n = 110), adolescents (n = 92), and adults (n = 177). After nucleic acids had been extracted from an endomyocardial biopsy, an explant, or autopsy samples, PCR and reverse transcription PCR were performed to detect the genomic sequences of enterovirus, adenovirus, cytomegalovirus (CMV), herpes simplex virus (HSV), Epstein-Barr virus (EBV), parvovirus, respiratory syncytial virus (RSV), and influenza A virus.

RESULTS

Viral genome was amplified (adenovirus = 142, enterovirus = 85, CMV = 18, parvovirus = 6, influenza A = 5, HSV = 5, EBV = 3, RSV = 1) from 239 (38%) of the 624 samples from myocarditis patients, including 26 patient samples in which dual infection was found. Virus was detected in 30 (20%) of 149 DCM patient samples; only adenovirus (n = 18) and enterovirus (n = 12) were detected.

CONCLUSIONS

Polymerase chain reaction identified adenovirus as the most common virus in the myocardium of children and adults with myocarditis and DCM. Although enteroviruses are also found in these patients, they appear to be a less common cause of myocarditis than adenovirus.

Prevalence of viral DNA in amniotic fluid of low-risk pregnancies in the second trimester

AIM

The association between fetal viral infection and adverse pregnancy outcome is well documented. However, the prevalence of common viral pathogens in the amniotic fluid of normal pregnancies is not established. The purpose of this study was to determine this prevalence in asymptomatic patients.

METHODS

This was a prospective observational study of patients at low risk for viral infection who were referred for second-trimester genetic amniocentesis. In patients with normal fetal anatomy on ultrasound and a normal fetal karyotype, a 2-ml aliquot of amniotic fluid obtained at amniocentesis was analyzed by multiplex polymerase chain reaction for cytomegalovirus (CMV), parvovirus B19, adenovirus, enterovirus, herpes simplex virus (HSV), respiratory syncytial virus (RSV) and Epstein-Barr virus (EBV).

RESULTS

Among 686 patients, advanced maternal age was the most common indication for genetic testing (n = 469, 68.4%), followed by elevated aneuploidy risk on triple screen (n = 164, 23.9%), elevated maternal serum alpha-fetoprotein (n = 20, 2.9%), previous aneuploidy (n = 16, 2.3%) and family history of inheritable disease (n = 14, 2.1%). Forty-four (6.4%) amniotic fluid samples were positive for viral genome. A single genome was amplified in 41 samples (93%). In three samples, two viral genomes were identified. Adenovirus was most frequently identified (37/44), followed by CMV (5/44), EBV (2/44), enterovirus (2/44) and RSV (1/44). Parvovirus and HSV were not identified. There was a bimodal seasonal variation in prevalence, with the highest prevalence during the summer and late winter.

CONCLUSION

Viral genome is commonly found in amniotic fluid with a sonographically normal fetus, and the prevalence follows a seasonal pattern. The mechanism, significance and effects of this asymptomatic viral presence require further study.

Human adenovirus and human cytomegalovirus infections in preterm newborns: no association with bronchopulmonary dysplasia

Connatal infection with human adenovirus (HAdV) has been recently proposed as a cofactor for the development of bronchopulmonary dysplasia (BPD) in preterm infants [Couroucli et al. 2000 Pediatr Res 47:225-232]. In another study, BPD was associated with an increased incidence of human cytomegalovirus (HCMV) infection [Sawyer et al. 1987 Am J Dis Child 141:303-305]. During a 18-mo study period, we investigated tracheal aspirates or pharyngeal aspirates and urine samples collected during the first month of life from 66 preterm newborns with very low birth weight (< or =1.500 g) for replication-potent HAdV as well as for adenoviral and HCMV DNA by virus culture and qualitative DNA PCR. Thus, our study included not only prenatal but also peri- and postnatal infections. Thirty-seven percent (24/66) of infants developed BPD(1), as defined by persistent oxygen dependency at day 28 of life. Replication-potent HAdV and/or adenoviral DNA could be detected repeatedly in tracheal aspirates/pharyngeal aspirates and/or urine from 20% (13/66) of preterm infants. Seventeen percent (4/24) of infants in the BPD(1) group and 21% (9/42) of infants in the non-BPD group had an HAdV infection, indicating that in our study the very recently proposed association between HAdV infection of the lung and BPD could not be confirmed. For comparison, active HCMV infection was diagnosed in 18% (12/66) of infants, 3 of which developed HCMV disease. 29% (7/24) in the BPD(1) group and 12% (5/42) in the non-BPD group were positive for HCMV. Again, there was no statistically significant association between HCMV infection and BPD. In summary, our findings indicate that HAdV and HCMV infection are frequent in preterm newborns with very low birth weight; however, a causal association with the development of BPD seems unlikely.

Viral infection of the trophoblast: time to take a serious look at its role in abnormal implantation and placentation?

Fragmentary evidence suggests that trophoblast viral infection may play a role in placental dysfunction, leading to complications including spontaneous miscarriage, preeclampsia, fetal growth restriction and preterm birth. Here, we review the mechanisms underlying differentiation and gestational age-dependent infection of trophoblast cells and the consequences of in vitro infection on trophoblast function. The relationship between trophoblast infection by common viruses and pregnancy outcomes is also analyzed. We conclude that there is sufficient evidence linking placental infection by common viruses, including viruses thought to be non-pathogenic or to have low pathogenicity, to indicate that this effect contributes to poor pregnancy outcome.

The mechanisms of placental viral infection

The placenta is a dynamic organ whose structure and function change throughout pregnancy. There is compelling evidence that the placenta plays an integral role in the vertical transmission of viruses, such as cytomegalovirus and human immunodeficiency virus, from the mother to the fetus. Although the sequelae of congenital viral infection (i.e., fetal anomalies, intrauterine fetal death, and persistent postnatal infection) may be devastating, very little is known about the passage of viruses across the placenta and the pathologic consequences of placental viral infection. We postulate that the syncytiotrophoblast, which forms a continuous barrier between the maternal and fetal circulation, is relatively resistant to viral infection. In support of this hypothesis, we observed that the susceptibility of trophoblast cells to infection by adenovirus and herpes simplex virus and the expression of viral receptors were reduced as trophoblast cells terminally differentiated into syncytiotrophoblast. Conversely, we observed that undifferentiated, extravillous trophoblast cells, which are susceptible to adenovirus infection, underwent pathologic changes (i.e., apoptosis) when infected by adenovirus in the presence of decidual lymphocytes (which were used to simulate the maternal immune response to viral infection). Based on these findings, we speculate that viral infection of extravillous trophoblast cells may negatively impact the process of placental invasion and predispose the mother and fetus to adverse reproductive outcomes that result from placental dysfunction.

Differential expression of the coxsackievirus and adenovirus receptor regulates adenovirus infection of the placenta

The molecular mechanisms and pathologic significance of placental viral infections are poorly understood. We investigated factors that regulate placental infection by adenovirus, which is the most common viral pathogen identified in fetal samples from abnormal pregnancies (i.e., fetal growth restriction, oligohydramnios, and nonimmune fetal hydrops). We also determined the pathologic significance of placental adenovirus infection. Northern hybridization, flow cytometry, and immunostaining revealed that placental expression of the coxsackievirus and adenovirus receptor (CAR) varied with gestational age and trophoblast phenotype. The CAR was continuously expressed in invasive or extravillous trophoblast cells but not in villous trophoblast cells. We postulate that the villous syncytiotrophoblast, which does not express CAR and is resistant to adenovirus infection, limits the transplacental transmission of viral pathogens, including adenovirus. Conversely, extravillous trophoblast cells underwent apoptosis when infected by adenovirus in the presence of decidual lymphocytes (which simulated the maternal immune response to viral infection). Thus, adenovirus infection and/or the maternal immune response to adenovirus infection induced the death of placental cell types that expressed CAR. Consequently, we speculate that adenovirus infection of extra-villous trophoblast cells may negatively impact the process of placental invasion and predispose the mother and fetus to adverse reproductive outcomes that result from placental dysfunction.

Hydrops fetalis

Although most NIH fetuses have poor prognosis, it is imperative to attempt to identify the underlying cause to present parents with the best estimate for prognosis and future outcomes. Identification of a disorder with a good prognosis may prevent unnecessary termination of pregnancy and give a chance for therapy. Identification of a disorder with poor prognosis may still provide information that may be unavailable after delivery regarding this and future pregnancies.

Detection of microorganisms in the tracheal aspirates of preterm infants by polymerase chain reaction: association of adenovirus infection with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is recognized as an important cause of morbidity and mortality in preterm infants. Because the role of congenital infections in BPD has been debated, the purpose of this study was to test the hypothesis that detection of infectious agents in tracheal aspirate samples was associated with the development of BPD. Tracheal aspirate samples were obtained within the 1st week of life and screened by polymerase chain reaction for adenovirus, cytomegalovirus, parvovirus, enteroviruses, Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma pneumoniae, and Chlamydia species. BPD was defined as persistent oxygen dependence at 28 d of age and 36 wk postconceptional age (PCA). Infants that expired before these time points were excluded from statistical analysis. Out of 89 infants studied, at 28 d of life, 13 had expired, 45 had BPD, and 31 had no BPD (controls). At 36 wk PCA, 15 infants expired, 39 still had BPD, and 35 did not. A significant increase in the frequency of adenovirus genome was identified in BPD patients compared with controls, both at 28 d of life (12/45 = 27% versus 1/31 = 3%: p< or =0.01) and at 36 wk PCA (10/39 = 29% versus 2/35 = 6%: p = 0.01). Other microorganisms were rarely detected and not associated with the development of BPD. This is the first study reporting the frequency of detection of adenovirus DNA in tracheal aspirate samples obtained during the 1st week of life from infants with BPD and suggests that prenatal acquisition may be important in the development of BPD.