Pathogenesis of nonimmune hydrops fetalis caused by intrauterine B19 infection

Prenatal parvovirus B19 infection

Parvovirus B19 (B19V) causes erythema infectiosum, a.k.a., fifth disease. This disease primarily affects children. It is generally self-limiting and subsides after 1-2 weeks. In pregnancy, the virus can cross the placenta and result in a fetal infection. This may lead to severe fetal anemia, hydrops fetalis, a miscarriage, or intrauterine fetal death. The risk of long-term sequelae also appears to be increased. About one-third of pregnant women are not immune to B19V and, therefore, are at risk to contract a primary infection. The seroconversion rate during pregnancy is generally around 1-2%. During a primary infection, maternal-fetal transplacental transmission of B19V occurs in about 30-50% of the cases and the risk of fetal infection increases with advancing gestational age. The risk of severe fetal anemia or hydrops is around 3-4% overall and is around 6-7% if the primary infection occurs before 20 weeks' gestation. Fetal monitoring in women with a primary B19V infection includes regular ultrasound examinations looking for evidence of hydrops fetalis and Doppler measurements of the middle cerebral artery peak velocity. Fetal blood sampling is performed if a significant anemia is suspected and, if such is found, an intrauterine blood transfusion is needed. This article provides an overview of the epidemiology, pathogenesis, clinical manifestations, diagnostic methods, and management of B19V infection during pregnancy.

Parvovirus B19 Infection in Pregnancy-Course of the Disease, Fetal Complications and Management Tools: A Case Series and Literature Review

Parvovirus B19 is a virus that causes a common and usually harmless infection in both children and adults. If the virus is transmitted transplacentally during pregnancy, it can have serious consequences for both the pregnant woman and the fetus. Potential complications include severe fetal anemia, which can lead to intrauterine fetal death. A common ultrasound finding in fetuses affected by parvovirus B19 is fetal edema, which is associated with a poor prognosis. Additionally, a rare but serious complication in pregnant women with parvovirus B19 infection is mirror syndrome. The diagnosis of parvovirus B19 infection during pregnancy necessitates close monitoring of the fetal condition. If fetal anemia is suspected, intrauterine transfusion is indicated to increase fetal survival. This study presents eight cases of parvovirus B19 infection in pregnant women, highlighting the various maternal-fetal complications encountered, along with diagnostic and treatment strategies.

Intravenous immunoglobulin treatment of congenital parvovirus B19 induced anemia - a case report

BACKGROUND

Parvovirus is a common childhood infection that could be very dangerous to the fetus, if pregnant women become infected. The spectrum of effects range from pure red blood cell aplasia with hydrops fetalis to meningoencephalitis, with many symptoms in between. Severe anemia in the setting of pure red blood cell aplasia is one of the more common effects that neonatal experience (if infected intrapartum), with the current gold standard treatment being intrauterine or postnatal packed red blood cell (PRBC) transfusions, yet intravenous immunoglobulin (IVIG) may be a superior treatment option.

CASE PRESENTATION

A preterm infant was born at 26th week of gestational age via emergency Cesarean section due to hydrops fetalis, with parvovirus B19 exposure one month prior. The infant tested positive for IgM antibodies against parvovirus B19. Among many other serious complications of both hydrops fetalis and premature delivery, the infant had severe unremitting anemia, and received many PRBC transfusion over the course of his 71-day-long neonatal intensive care unit stay. During a follow up appointments as outpatient, his blood tests showed persistent high copies of parvovirus B19. He was then supported with PRBC transfusions and treated with IVIG. After three doses of IVIG, the infant's parvovirus B19 viral copy numbers have dramatically reduced and the infant did not require any more PRBC transfusions.

CONCLUSIONS

IVIG infusion effectively treated the parvovirus B19 infection and restored erythropoiesis making the child transfusion independent. Furthermore, since IVIG is safe and readily crosses the placenta, further studies are needed to determine if IVIG should be considered as an alternative prenatal treatment for congenital parvovirus B19 infection.

Placental Immune Responses to Viruses: Molecular and Histo-Pathologic Perspectives

As most recently demonstrated by the SARS-CoV-2 pandemic, congenital and perinatal infections are of significant concern to the pregnant population as compared to the general population. These outcomes can range from no apparent impact all the way to spontaneous abortion or fetal infection with long term developmental consequences. While some pathogens have developed mechanisms to cross the placenta and directly infect the fetus, other pathogens lead to an upregulation in maternal or placental inflammation that can indirectly cause harm. The placenta is a temporary, yet critical organ that serves multiple important functions during gestation including facilitation of fetal nutrition, oxygenation, and prevention of fetal infection in utero. Here, we review trophoblast cell immunology and the molecular mechanisms utilized to protect the fetus from infection. Lastly, we discuss consequences in the placenta when these protections fail and the histopathologic result following infection.

Parvovirus B19 infection during pregnancy and risks to the fetus

Parvovirus B19 infects 1 to 5% of pregnant women, generally with normal pregnancy outcomes. During epidemics, the rate of infection is higher. Major congenital anomalies among offspring of infected mothers are rare, as the virus does not appear to be a significant teratogen. However, parvovirus B19 infection may cause significant fetal damage, and in rare cases, brain anomalies and neurodevelopmental insults, especially if infection occurs in the first 20 weeks of pregnancy. Parvovirus B19 is also an important cause of fetal loss, especially in the second half of pregnancy when spontaneous fetal loss from other causes is relatively rare. Parvovirus B19 infection may affect many fetal organs and can cause severe anemia, following fetal erythroid progenitor cells infection and apoptosis, especially in fetuses, that have shortened half-life of erythrocytes. Severe anemia may cause high output cardiac failure and nonimmune hydrops fetalis. In addition, parvovirus B19 may directly infect myocardial cells and produce myocarditis that further aggravates the cardiac failure. Intrauterine fetal transfusion is commonly used for the treatment of severe fetal anemia with survival rates of 75 to 90% and significant reduction of fetal morbidity. Only 66 cases were evaluated neurodevelopmentally, of which 10 (16%) had slight or severe neurodevelopmental problems. Because parvovirus B19 infection can cause severe fetal morbidity and mortality, it should be part of the routine work-up of pregnant women who have been exposed to the virus or of pregnancies with suspected fetal hydrops. Assessment for maternal infection during pregnancy is especially important during epidemics, when sero-conversion rates are high. Birth Defects Research 109:311-323, 2017. © 2017 Wiley Periodicals, Inc.

Etiology and Perinatal Outcome of Nonimmune Hydrops Fetalis in Southern China

Objective  This study aims to analyze the etiology and perinatal outcome of nonimmune hydrops fetalis (NIHF) in Southern China. Methods  All cases with NIHF diagnosed antenatally from January 1, 2007 to December 31, 2014 were identified and analyzed. Results  Total 482 cases of NIHF were identified during the study period. The most common cause of NIHF was hemoglobin (Hb) Bart's disease (61.8%), followed by chromosomal abnormalities (13.5%), idiopathic etiology (13.1%), cardiac abnormalities (6.4%), and others (5.2%). After 20 weeks' gestation, a total of 408 cases of NIHF presented, including Hb Bart's disease (279 cases), cardiac abnormalities (27 cases), and infection (7 cases). NIHF caused by chromosomal abnormalities mainly presented between 15 and 19 weeks' gestation. Of the 482 cases, 459 cases elected termination of pregnancy. The remaining 23 cases elected to continue their pregnancy. Among them, 14 (60.9%) resulted in intrauterine fetal death, 6 had neonatal death, 3 infants survived to 1 year of age. Of the three infants, one has cerebral palsy, and the remaining two are normal. Conclusions  Hb Bart's disease is the most common cause of NIHF in Southern China. An effective prenatal screening and counseling program for thalassemia in this region may be the most effective way to lower the incidence NIHF.

Comparative evaluation of two commercial enzyme immunoassays for serodiagnosis of human parvovirus B19 infection

The present study describes the performance of two commercial enzyme immunoassays (EIAs) employing recombinant capsid proteins derived from baculovirus or from yeast for diagnosis of human parvovirus B19 (B19) infection. At first, 450 sera from routine daily practice submitted consecutively for B19 antibody testing during a 2-week period in March 2006 were tested. Eighty percent of the routine sera were from pregnant women. There was a high degree of accordance between the two assay systems in detection of B19 IgG antibodies (98.9%) and B19 IgM antibodies (98.7%). Specific antibody concentrations of serum specimens with discordant test results (n=11) were within or close to the equivocal range of the respective assay. Subsequently, specificity and sensitivity of the IgM EIAs were assessed in detail by testing 160 sera collected from patients with a defined disease state. Specificity ranged between 94.2 and 98.5% in patients (n=70) with other acute infections or autoimmune diseases. In sera from pregnant women (n=30) and children (n=30) with acute B19 infection, both assays were 100% sensitive. Whereas sensitivity varied from 63.0 to 70.0% in pregnant women (n=30) investigated 8-12 weeks after onset of disease. According to our evaluation the diagnostic performance of the two assay systems appears to be substantially equivalent. Fetal hydrops is sometimes a late complication of gestational B19 infection and maternal B19 IgM antibodies may already have declined to undetectable levels at the time of clinical diagnosis. A negative B19 IgM test during pregnancy should therefore be interpreted with caution.

Nonimmune Hydrops Fetalis Diagnosed during the Second Half of Pregnancy in Southern China

OBJECTIVE

To analyze the etiologies of nonimmune hydrops fetalis (NIHF) for a southern section of China.

METHODS

138 cases of NIHF presenting after 20 weeks' gestation over a 10-year period were reviewed.

RESULTS

The causes of fetal hydrops were identified in 92.0%. Homozygous alpha-thalassemia dominated as the cause of NIHF (55.1%), followed by infection (15.2%) and structural abnormalities (10.9%). No obvious cause was identified in 11 cases (8.0%). Termination of pregnancy was performed in 131 cases.

CONCLUSIONS

Homozygous alpha-thalassemia is the most common cause of NIHF in southern China. An effective prenatal thalassemia screening program should be established in this high prevalence region.

Hydrops foetus universalis – a retrospective study

A szerzők a hydrops foetus előfordulási gyakoriságát, létrejöttének okait vizsgálták. Öt év alatt 555 foetalis és neonatális autopsziás vizsgálatot végeztek. Hydropsot igazoltak 28 magzatnál. Három esetben Rh-izoimmunizáció állt a háttérben, 25 foetusnál nem immun hydrops került megállapításra. Huszonöt esetben sikerült a hydrops kiváltó okát tisztázni, az ok 3 esetben felderítetlen maradt. Tizenkét esetben középidős spontán vetélés, illetve in utero elhalás történt, míg 12 foetusnál orvosi indok alapján történt a terhesség terminálása. Emellett 4 újszülöttkorban meghalt beteget is vizsgáltak. Az orvosi indok alapján történő terhességmegszakításnál a foetusok átlagos kora a 16. és a 20. gesztációs hét között volt, míg a középidős spontán vetélés és in utero elhalás esetén ez a 24. terhességi hetet jelentette. A patológiai vizsgálat valamennyi esetben a terhességi korhoz képest várható testsúlynövekedését, periferiás oedemát, ascitest, illetve hydrothoraxot igazolt. Az esetek felében hydropericardium is látható volt. Hepatosplenomegália, cardiomegália, pulmonális hypoplasia, fokozott extramedulláris hemopoezis, placenta oedema valamennyi esetben megfigyelhető volt. A nem immun hydrops hátterében a következő rendellenességeket találták: 4 esetben cardiális malformatiót, 1 esetben szkeletális rendellenességet, 3 foetusnál kromoszómarendellenességet, 2 foetusnál cysticus hygromát, 3 esetben iker-iker transzfúzióval járó monochorialis diamnialis ikerterhességet, 7 esetben infekciót, 1 foetusnál sacrococcygeális teratomát. Két esetben a kiváltó ok anyai betegséget jelentett. A klinikai és patológiai diagnózisokat összehasonlítva megállapították, hogy a nem immun hydrops kórokával kapcsolatban csupán 3 esetben volt teljes egyezés a klinikai véleménnyel. A patológiai vizsgálat által feltárt kórokot az öröklődés, terápiás lehetőségek mérlegelése szempontjából 10 esetben szignifikánsnak véleményezték. A szerzők kiemelik nem immun hydrops esetén a részletes patológiai vizsgálat szükségességét, a klinikai vizsgálatokkal való korreláció meghatározásának fontosságát, a szerológiai vizsgálatok jelentőségét és a társszakmákkal való együttműködés szükségességet a hydropsos magzatokkal kapcsolatos további teendők meghatározása érdekében.

Current epidemiological aspects of human parvovirus B19 infection during pregnancy and childhood in the western part of Germany

This investigation was undertaken to provide detailed information on the epidemiology of human parvovirus B19 (B19) infection during pregnancy and childhood in the western part of Germany. Between 1997 and 2004, 40,517 sera from pregnant women aged 17-45 years and 6060 sera from children and young adults were tested for B19 IgG and IgM in our laboratory. In pregnant women, both the history of a 'specific' (OR 7.7, 95% CI 5.2-11.4) and a 'non-specific' rash (OR 3.3, 95% CI 1.5-7.1) was predictive for B19 IgM positivity. The B19 IgG prevalence was 69.2% (4097/5924) in a subgroup of asymptomatic pregnant women screened for B19 antibodies. In children, the age-specific IgG-positivity rate increased from 12.2% (66/541) at 2 years of age to 71.9% (396/551) in those older than 10 years. In conclusion, the prevalence of B19 IgG in pregnant women from the western part of Germany is higher then previously reported. Contact with children aged 3-10 years is a major risk factor for exposure to B19. Pregnant women with the history of a 'non-specific' rash should also be evaluated for acute B19 infection.

Detection of human parvovirus B19 nonstrutural protein DNA by nested-polymerase chain reaction in gravida serum and pregnant tissues

A new nested-polymerase chain reaction (nested-PCR) assay was developed to detect human parvovirus B19 DNA corresponding to the nonstructural protein in clinical specimens in a routine diagnostic laboratory. The sensitivity of this highly specific assay was up to 0.005 fg of B19 DNA. Parvovirus B19 was identified in sera of 20 pregnant women with abnormal pregnant outcome. Among these 20 cases, intrauterine parvovirus infection did exist in 7 pregnant women because parvovirus B19 DNA was detected in the pregnant tissues of them such as placenta tissues, chorionic villi, amniotic fluid, fetal spleen, liver and abdominal fluids.

Incidence of parvovirus B19 infection among an unselected population of pregnant women in the Netherlands: A prospective study

OBJECTIVE

To evaluate seroprevalence of anti-parvovirus B19 IgG immunoglobulins and the rate of seroconversion in seronegative pregnant women.

DESIGN

Prospective assessment of anti-parvovirus B19 IgG immunoglobulins in an unselected population of pregnant women booked for antenatal care from 1998 to 2000.

SETTING

Maternity departments of an academic hospital and four affiliated teaching hospitals in the Netherlands.

SUBJECTS

Two thousand five hundred and sixty seven pregnant women.

MAIN OUTCOME MEASURES

Seroprevalence of anti-parvovirus B19 IgG immunoglobulin in the first trimester of pregnancy and subsequent seroconversion in those women who were tested negative for parvovirus B19 antibodies in the first trimester of pregnancy.

RESULTS

The estimated seroprevalence of anti-parvovirus B19 IgG immunoglobulins among the study population is 70% (95% CI: 68-71) in the first trimester of pregnancy. Seven hundred and seventy nine women tested negative for parvovirus B19 antibodies in the first trimester of pregnancy. Paired testing in these women confirmed 18 seroconversions. Based on these findings the estimated incidence of maternal parvovirus B19 infection in this population among seronegative Dutch women is 2.4% (95% CI: 1.4-3.7).

CONCLUSION

Maternal infection with parvovirus B19 is relatively common. However, it is argued that in the Netherlands routine assessment of parvovirus antibodies in pregnant women is not warranted as there is a low risk of adverse fetal outcome and measures to prevent the parvovirus B19 infection and its consequences are very limited.

Clinical Manifestations and Outcomes of Parvovirus B19 Infection during Pregnancy in Japan

Parvovirus B19 is a small DNA virus. Infection with parvovirus B19 during pregnancy may cause serious complications in the fetus, including hydrops fetalis and fetal death. The purpose of the present study is to clarify the clinical manifestations and outcomes of parvovirus B19 infection during pregnancy. This prospective study enrolled 478 women with suspected B19 infections during pregnancy between 1999 and 2004. One hundred cases (21%) of B19 infection were detected in 478 pregnant women who had been exposed to B19. Serological infection was confirmed by measurement of B19-specific IgM and IgG in sera. Forty-nine cases reported maternal clinical symptoms and 51 cases were asymptomatic. Facial rash was the most common symptom, with 51% (25/49) of the symptomatic patients complaining of either a facial, body or limb rash. The most common infectious source was children living in the home. Overall, the incidence of adverse fetal effects (including hydrops fetalis and fetal death) related to intrauterine B19 infection was 7% (7/100), and all seven cases were exposed to B19 infection before 20 weeks of gestation. Although half of the cases with parvovirus B19 infections during pregnancy were asymptomatic, patients with adverse fetal effects tended to be symptomatic including rash and fever. These clinical data may supply useful information to produce clinical guidelines for managing B19 infection during pregnancy.

Uptake of hepatitis B virus into choriocarcinoma cells in the presence of proinflammatory cytokine tumor necrosis factor-alpha

OBJECTIVE

The aim of this study was to establish an in vitro experimental model that mimics the interaction of hepatitis B virus (HBV) and the trophoblastic barrier.

STUDY DESIGN

The barrier was represented by choriocarcinoma cell line, JAR cells, which were incubated with HBV in the presence or absence of tumor necrosis factor-alpha (TNF-alpha). At 12-hour intervals after a 24-hour incubation, the infection efficiency was examined by enzyme-linked immunosorbent assay of culture supernatants, immunohistochemistry of cell slides, Western blotting of cell lysates, polymerase chain reaction amplification for viral DNA of infected cells, and transmission electron microscopy for HBsAg particles in infected cells.

RESULTS

In the absence of TNF-alpha, many JAR cell colonies showed a negative or punctate positive pattern after incubation with HBV. But when JAR cells were pretreated with TNF-alpha before cocultured with HBV, the infection was greatly enhanced, whereas the differences observed between the various time points in the second series of experiments did not reach a statistically significant level.

CONCLUSION

JAR cells can support HBV infection in the presence of TNF-alpha. Our in vitro system provides key basis on further study reflecting mechanism of in vivo HBV intrauterine infection and transfer.

Advances in the biology, diagnosis and host-pathogen interactions of parvovirus B19

Increased recognition of parvovirus B19 (B19), an erythrovirus, as a significant human pathogen that causes fetal loss and severe disease in immunocompromised patients has resulted in intensive efforts to understand the pathogenesis of B19-related disease, to improve diagnostic strategy that is deployed to detect B19 infection and blood-product contamination and, finally, to elucidate the nature of the cellular immune response that is elicited by the virus in diverse patient cohorts. It is becoming clear that at least three related erythrovirus strains (B19, A6/K71 and V9) are circulating in the general population and that viral entry into target cells is mediated by an expanding range of cellular receptors, including P antigen and beta-integrins. Persistent infection by B19 is emerging as a contributory factor in autoimmune disease, a hypothesis that is constrained by the detection of B19 in the skin of apparently healthy individuals. B19 infection during pregnancy may account for thousands of incidences of fetal loss per annum in Europe, North America and beyond, yet there is currently only minimal screening of pregnant women to assess serological status, and thereby risk of infection, upon becoming pregnant. Whilst major advances in diagnosis of B19 infection have taken place, including standardization of serological and DNA-based detection methodologies, blood donations that are targeted at high-risk groups are only beginning to be screened for B19 IgG and DNA as a means of minimizing exposure of at-risk patients to the virus. It is now firmly established that a Th1-mediated cellular immune response is mounted in immunocompetent individuals, a finding that should contribute to the development of an effective vaccine to prevent B19 infection in selected high-risk groups, including sickle-cell anaemics.

Frequent detection of parvovirus B19 genome in the myocardium of adult patients with idiopathic dilated cardiomyopathy

Aside from enteroviruses and other viruses, e.g., adenoviruses, which are known to be associated with idiopathic dilated cardiomyopathy (IDC), a cardiac tropism is also attributed to parvovirus B19 (PVB19). The purpose of the present study was to determine the prevalence of enterovirus, adenovirus and PVB19 genomes in the myocardium of adult patients with IDC and to analyze the significance of PVB19 with regard to the course of the disease, as compared to the other cardiotropic viruses. In 52 adult patients with IDC and 10 control patients with normal left ventricular ejection fraction (> or =55%) undergoing coronary artery bypass surgery, myocardial tissue samples were investigated for enteroviral RNA using polymerase chain reaction (PCR) and Southern blot hybridization of the PCR product. Specific nested PCR was used to assess the prevalence of adenovirus and PVB19 DNA, in addition to sequencing of the latter. The clinical and echocardiographic course of the disease was followed for a mean (+/- SD) period of 21.1+/-9.5 months. Fourteen of the 52 patients (27%) were enterovirus-positive, 2/52 (4%) patients were adenovirus-positive, 14/52 (27%) patients were PVB19-positive, 8/52 (15%) patients were enterovirus plus PVB19-positive, and in 14/52 (27%) patients no viral genomes were found. Six patients died during the follow-up period, without any significant difference between the patient groups: 1/14 (7%) in the enterovirus-positive, 0/2 (0%) in the adenovirus-positive, 2/14 (14%) in the PVB19-positive, 1/8 (12.5%) in the enterovirus plus PVB19-positive, and 2/14 (14%) in the virus-negative group. PVB19 genome was found in 4 of the 10 (40%) control patients, but no enterovirus or adenovirus genomes were detected in these patients. In conclusion, in the myocardium of patients with IDC, PVB19 is detectable as frequently as enteroviral genome. PVB19-positive patients with IDC have a rather favorable prognosis and do not differ significantly from the other virus-positive or virus-negative patient groups with respect to survival. Finally, the pathogenetic and prognostic significance of PVB19 in IDC still remains unclear.

Ex vivo cytokine responses against parvovirus B19 antigens in previously infected pregnant women

Parvovirus B19 infection is a significant cause of fetal death. The aim of this study was to investigate the role of maternal immune status in modulating susceptibility to fetal B19 infection. Peripheral blood was obtained from pregnant women (n = 199) with no clinical evidence of recent B19 infection. Evaluation of ex vivo T cell responses from 149/199 individuals showed significantly higher interferon-gamma levels for seropositive individuals following VP1 (268 +/- 36 versus 103 +/- 19 pg/ml; P = 0.003) and VP2 (242 +/- 42 versus 91 +/- 16 pg/ml; P = 0.01) antigen stimulation. Significantly higher levels of interleukin-2 were also observed in seropositive individuals following both VP1 (P = 0.0003) and VP2 (P = 0.0005) stimulation. The observed Th1 cellular response is lower than that documented previously for non-pregnant individuals and strongly suggests that diminution of the maternal anti-viral immune response may increase susceptibility to fetal B19 infection.

Revised clinical presentation of parvovirus B19-associated intrauterine fetal death

Adverse pregnancy outcome due to human parvovirus B19 (hereafter referred to as "parvovirus B19") has been characterized, in numerous reports, as an event that occurs during the first and second trimesters and is strongly associated with symptoms of fetal hydrops. Recent findings have indicated that parvovirus B19-associated intrauterine fetal death (IUFD) is also a problem in late gestation, although its clinical presentation is aberrant, lacking signs of fetal hydrops. We outlined the clinical presentation and assessed the frequency of parvovirus B19 infection in a retrospective analysis of 92 unselected cases of IUFD that occurred during or after gestational week 22. By polymerase chain reaction, parvovirus B19 DNA was detected in 13 (14%) of the 92 cases. Only 2 of the parvovirus B19 DNA-positive cases were hydropic, both representing early IUFDs. This finding indicates that parvovirus B19-associated IUFD in late gestation is a common finding and that hydropic presentation is rare. This knowledge may contribute to a reduction in the number of unexplained cases of IUFD.

Human parvovirus B19 infection in pregnancy: should screening be offered to the low-risk population?

Human parvovirus B19 infection during pregnancy can result in fetal hydrops and death. Intra-uterine transfusion in hydropic fetuses affected by the virus can reduce perinatal deaths. Up to 33% of women with this infection are asymptomatic. In view of the significant adverse outcomes, the role of routine screening among low-risk pregnant women is discussed.