Re-evaluation of the true rate of hepatitis C virus mother-to-child transmission and its novel risk factors based on our two prospective studies

Safety and Efficacy of Antiviral Drugs and Vaccines in Pregnant Women: Insights from Physiologically Based Pharmacokinetic Modeling and Integration of Viral Infection Dynamics

Addressing the complexities of managing viral infections during pregnancy is essential for informed medical decision-making. This comprehensive review delves into the management of key viral infections impacting pregnant women, namely Human Immunodeficiency Virus (HIV), Hepatitis B Virus/Hepatitis C Virus (HBV/HCV), Influenza, Cytomegalovirus (CMV), and SARS-CoV-2 (COVID-19). We evaluate the safety and efficacy profiles of antiviral treatments for each infection, while also exploring innovative avenues such as gene vaccines and their potential in mitigating viral threats during pregnancy. Additionally, the review examines strategies to overcome challenges, encompassing prophylactic and therapeutic vaccine research, regulatory considerations, and safety protocols. Utilizing advanced methodologies, including PBPK modeling, machine learning, artificial intelligence, and causal inference, we can amplify our comprehension and decision-making capabilities in this intricate domain. This narrative review aims to shed light on diverse approaches and ongoing advancements, this review aims to foster progress in antiviral therapy for pregnant women, improving maternal and fetal health outcomes.

Viral hepatitis C during pregnancy: prevalence, impact on perinatal outcomes, patient management tactics (literature review)

The article presents modern ideas about the impact of viral hepatitis C on the course of pregnancy, the severity of maternal disease associated with it: methods of delivery and possible vertical transmission. Epidemiological data on the prevalence in the world and the Russian Federation, risk factors for perinatal HCV transmission, and the course of pregnancy in women infected with HCV are shown. The search for the necessary literary sources was carried out in the databases Scopus, PubMed, MedLine, The Cochrane Library, RSCI.

Pregnancy and fetal outcomes of chronic hepatitis C mothers with viremia in China

BACKGROUND

Data that assess maternal and infant outcomes in hepatitis C virus (HCV)-infected mothers are limited.

AIM

To investigate the frequency of complications and the associated risk factors.

METHODS

We performed a cohort study to compare pregnancy and fetal outcomes of HCV-viremic mothers with those of healthy mothers. Risk factors were analyzed with logistic regression.

RESULTS

Among 112 consecutive HCV antibody-positive mothers screened, we enrolled 79 viremic mothers. We randomly selected 115 healthy mothers from the birth registry as the control. Compared to healthy mothers, HCV mothers had a significantly higher frequency of anemia [2.6% (3/115) vs 19.0% (15/79), P < 0.001] during pregnancy, medical conditions that required caesarian section [27.8% (32/115) vs 48.1% (38/79), P = 0.004], and nuchal cords [9.6% (11/115) vs 34.2% (27/79), P < 0.001]. In addition, the mean neonatal weight in the HCV group was significantly lower (3278.3 ± 462.0 vs 3105.1 ± 459.4 gms; P = 0.006), and the mean head circumference was smaller (33.3 ± 0.6 vs 33.1 ± 0.7 cm; P = 0.03). In a multivariate model, HCV-infected mothers were more likely to suffer anemia [adjusted odds ratio (OR): 18.1, 95% confidence interval (CI): 4.3-76.6], require caesarian sections (adjusted OR: 2.6, 95%CI: 1.4-4.9), and have nuchal cords (adjusted OR: 5.6, 95%CI: 2.4-13.0). Their neonates were also more likely to have smaller head circumferences (adjusted OR: 2.1, 95%CI: 1.1-4.3) and lower birth weights than the average (≤ 3250 gms) with an adjusted OR of 2.2 (95%CI: 1.2-4.0). The vertical transmission rate was 1% in HCV-infected mothers.

CONCLUSION

Maternal HCV infections may associate with pregnancy and obstetric complications. We demonstrated a previously unreported association between maternal HCV viremia and a smaller neonatal head circumference, suggesting fetal growth restriction.

Clinical practice guidelines for the management of children with mother-to-child transmitted hepatitis C virus infection

BACKGROUND

The first guidelines for care of pregnant women carrying the hepatitis C virus (HCV) and their infants were published in 2005 in Japan. Since then, evidence has gradually accumulated worldwide regarding the natural course and treatment of this condition and, especially in recent years, treatment for chronic hepatitis C in adult patients has made great progress. However, the clinical practice policy for children has not been standardized, and new clinical practice guidelines for children with mother-to-child (MTC) transmitted HCV infection have become necessary.

METHODS

In the development of the current guideline, we requested cooperation from The Japanese Society for Pediatric Infectious Diseases, The Japan Society of Hepatology, and the Japan Society of Obstetrics and Gynecology. The committee members were recommended and approved by each society to participate in developing the guidelines. The guideline was also created in accordance with the Minds Guide for Practice Guideline Development. The statements were prepared by consensus-building using the Delphi method, based on the comprehensively searched academic papers and guidelines. These articles were retrieved through searching the PubMed, Cochrane Library, and the Igaku Chuo Zasshi databases.

RESULTS

Eight clinical questions (CQs) with clinical statements were developed regarding etiology (CQs 1-3), diagnosis (CQs 4 and 5), and treatment (two CQs 6 and 7). In each statement, the consensus rate, evidence level, and recommendation level were determined.

CONCLUSION

The guidelines will be helpful in the management of children with hepatitis C MTC transmission.

Estimating paediatric hepatitis C prevalence in the United States

Over 70 million individuals are infected with hepatitis C virus (HCV) worldwide. Yet most prevalence data are in the adult population, with little focus on paediatrics, partially due to the scarcity of public data. The objective of this paper is to examine HCV prevalence in children by estimating prevalence rates among women, given the assumption that most cases are vertically transmitted. Between 2001 and 2017, maternal HCV infection affected ~ 0.24% of all births, with prevalence increasing by at least 261%. On average, approximately 0.01% of the total number of live births were infected with HCV, with a 245% increase in the number of children born with the infection. HCV epidemiology has evolved, with women of childbearing age representing a greater proportion of infected individuals in the United States, and infants born to infected mothers being at risk. We therefore recommend a greater public health focus of HCV on the paediatric population.

Perinatal transmission of hepatitis C virus: an update

Infection with hepatitis C virus (HCV) is a major health problem worldwide. A large proportion of perinatal HCV infections are silent and may present later in adulthood with long-term complications. HCV has no effective immune prophylaxis and hence appropriate follow-up of all infants born to HCV-infected mothers is necessary. Universal antenatal screening for HCV is largely debatable. Intrauterine and partum transmission of HCV are both possible and higher rates are associated with a high maternal serum viral load (> 10⁶ copies per milliliter), concomitant HIV infection, prolonged or difficult delivery, and invasive fetal monitoring during delivery. Infection during pregnancy and infancy needs to be investigated more in order to design management strategies for perinatal transmission of HCV most effectively. The recently approved new-generation, oral, direct-acting antiviral drugs may open a new era in HCV therapy for pregnant women and infected infants if proved to be safe during conception and infancy.

Mother-to-child transmission of hepatitis C virus

This review reinforces the lack of a single maternal risk factor that is highly associated with vertical transmission (VT) of the infection with hepatitis C virus (HCV): indeed HCV RNA levels, mode of delivery, breast feeding, viral genotype or maternal IL28B status were not associated with HCV VT.

Liver Disease During Pregnancy: A Challenging Clinical Issue

One of the least studied topics in the field of obstetrics is liver disease during pregnancy, which creates a challenge for both gynecologists and hepatologists. Approximately 3% of pregnant women are affected by some form of liver disease during pregnancy. Some of these conditions can be fatal for both the mother and child. In addition, 3 types of liver disease need to be differentiated during pregnancy. One type is liver disease directly related to pregnancy, which can occur at a specific time during pregnancy. Another type is liver disease not related to pregnancy, which can occur at any time, such as viral- or drug-induced hepatitis. Furthermore, pregnancy can occur in women with pre-existing liver disease. It is essential that the clinicians are familiar with this disorder so they can respond promptly and appropriately in all of these situations, especially when emergency delivery is needed and must not be postponed.

Incidence of HCV induced-Esophageal varices in Egypt: Valuable knowledge using data mining analysis

Esophageal varices is one of the most important comorbidity related liver cirrhosis, patients usually presented with hematemesis, melena, or both, ultimately 20% is the mortality during the first attack, hence we aimed to investigate the incidence of such esophageal varices related chronic Hepatitis C virus (HCV) in randomized Egyptian population.One thousand eighteen Egyptian patients, aged between 17 and 58 years, positive for Hepatitis C virus genotype 4 (HCV-4) by enzyme linked immunosorbent assay Ab and HCV RNA-polymerase chain reaction were screened for the presence of esophageal varices.Incidence of esophageal varices was 62.3%; 635 patients, those with large Esophageal varices (LEVs) was 47.4%; 301 patients. Model for end-stage liver disease (MELD) score has not been significantly improved post variceal band ligation (VBL). Using 2D U/S was useful for EVs prediction.Incidence of esophageal varices in HCV Egyptian patients still high, valuable knowledge would be helpful in clinical field have been discovered by data mining computational intelligent analysis using in practical medicine to improve overall health care.

Mycobacterial L-forms are found in cord blood: A potential vertical transmission of BCG from vaccinated mothers

Our previous studies showed that mycobacterial L-forms persist in the blood of BCG vaccinated people and that BCG vaccine is able to produce, under appropriate conditions, filterable, self-replicating L-bodies with virus-like size. Because filterability is one of the characteristics of L-forms, considerable interest has been shown in their capacity to cross the maternal-fetal barrier. The current study demonstrated isolation of mycobacterial L-form cultures from umbilical cord blood of 5 healthy newborns of healthy mothers vaccinated previously with BCG. The isolated cultures showed distinctive growth characteristics of cell wall deficient L-form bacteria. Transmission electron microscopy demonstrated presence of L-bodies with extremely small size of 100 nm and revealed morphological transformations, typical for L-forms. IS6110 Real Time PCR assay confirmed that all L-form isolates were of mycobacterial origin and belonged to Mycobacterium tuberculosis complex which includes vaccinal BCG substrains. In conclusion, we could suggest that reproductive filterable L-bodies of BCG origin are able to fall in blood circulation of the fetus by vertical transmitted pathway and colonize newborns.

Peginterferon Therapy in Children With Chronic Hepatitis C: A Nationwide, Multicenter Study in Japan, 2004-2013

OBJECTIVES

The aim of the present study was to review the medical treatment of Japanese children and adolescents with chronic hepatitis C in the past 10 years.

METHODS

This nationwide, multicenter study evaluated patients who were younger than 18 years of age when diagnosed with chronic hepatitis C virus (HCV) infection and were treated with pegylated interferon (PEG-IFN) monotherapy or PEG-IFN/ribavirin (RBV) combination therapy between 2004 and 2013. The subjects' median age was 10 (3-18) years, with a male to female ratio of 52:50 and a genotype-1 to genotype-2 ratio of 45:57. Among the 102 patients, 18 received PEG-IFN monotherapy and 84 received PEG-IFN/RBV combination therapy. The IL28B genotype polymorphism was analyzed in patients infected with genotype-1.

RESULTS

In patients with HCV genotype-1 infections, sustained virological response (SVR) rates obtained by PEG-IFN monotherapy and by PEG-IFN/RBV combination therapy were 100% (2/2) and 72% (31/43), respectively. In patients with HCV genotype-2 infections, SVRs were 75% (12/16) and 100% (41/41), respectively. In 32 genotype-1 patients available for the IL28B genotype (rs8099917), SVR was achieved in more patients in the IL28B major allele group than in the minor allele group (15/17 vs 7/15, P = 0.021) after PEG-IFN/RBV combination therapy. The frequencies of adverse events were similar between the treatment regimens.

CONCLUSIONS

Overall, both therapies showed encouraging results, and were reasonably safe in children and adolescents with chronic hepatitis C. The IL28B genotype was useful for predicting the treatment response to PEG-IFN/RBV combination therapy in this cohort.

CD4+ and CD8+ T Cell Activation in Children with Hepatitis C

OBJECTIVES

To assess if peripheral T cell populations in children with chronic hepatitis C virus (HCV) infection would show evidence of activation/exhaustion and an attenuated functional response.

STUDY DESIGN

Compared with adults, children with HCV infection have a higher rate of spontaneous viral clearance. In adults, chronic HCV has been linked to T cell exhaustion. Little is known of the immune status of children with HCV. Peripheral blood mononuclear cells were isolated from 16 children with HCV (6 males, 10 females; mean age 8.6 years, range 2-17), 16 age- and sex-matched control children without HCV infection, and 20 adults with chronic HCV. Multiparameter flow cytometry was performed to characterize T cell differences across the 3 groups.

RESULTS

Controls and children with HCV had similar levels of CD4(+), CD8(+), and γδ(+) T cells. Children with HCV demonstrated a decrease in naïve T cells compared with control children and increased activation/exhaustion marker expression on both CD8(+) and CD4(+) T cells. Transcription factor analysis suggested functional activation of T cells in children with HCV; however, only the CD4(+) subset had enhanced cytokine production (interferon gamma and interleukin-2) compared with control children.

CONCLUSIONS

The HCV response in children is characterized by several changes in T cell phenotype. Many of these changes, such as increased T cell expression of programmed cell death-1, are similar to responses in adults. Of note, cytokine production by CD4(+) helper T cells is increased in children with HCV compared with age- and sex-matched control children, which may influence long-term prognosis in children with HCV.

AISF position paper on liver disease and pregnancy

The relationship between liver disease and pregnancy is of great clinical impact. Severe liver disease in pregnancy is rare; however, pregnancy-related liver disease is the most frequent cause of liver dysfunction during pregnancy and represents a severe threat to foetal and maternal survival. A rapid differential diagnosis between liver disease related or unrelated to pregnancy is required in women who present with liver dysfunction during pregnancy. This report summarizes the recommendation of an expert panel established by the Italian Association for the Study of the Liver (AISF) on the management of liver disease during pregnancy. The article provides an overview of liver disease occurring in pregnancy, an update on the key mechanisms involved in its pathogenesis, and an assessment of the available treatment options. The report contains in three sections: (1) specific liver diseases of pregnancy; (2) liver disease occurring during pregnancy; and (3) pregnancy in patients with pre-existing chronic liver disease. Each topic is discussed considering the most relevant data available in literature; the final statements are formulated according to both scientific evidence and clinical expertise of the involved physicians, and the AISF expert panel recommendations are reported.

Risk factors for vertical transmission of hepatitis C virus: a single center experience with 710 HCV-infected mothers

OBJECTIVE

The aim of this study was to analyze the risk factors on the perinatal transmission of hepatitis C virus (HCV).

STUDY DESIGN

A retrospective cohort study with 711 infants born to 710 HCV-infected mothers was conducted at the Hospital La Fe, in Valencia, Spain, from 1986 to 2011. As potential risk factors for transmission we analyzed: maternal age, mode of acquisition of HCV infection, HIV co-infection, antiretroviral treatment against HIV, CD4 cell count, HIV and HCV viral load, liver enzyme levels during pregnancy, smoking habit, gestational age, intrapartum invasive procedures, length of rupture of membranes, length of labor, mode of delivery, episiotomy, birth weight, newborn gender and type of feeding.

RESULTS

Overall perinatal HCV transmission rate was 2.4%. The significant risk factors related with HCV transmission were maternal virus load >615copies/mL (OR 9.3 [95% CI 1.11-78.72]), intrapartum invasive procedures (OR 10.1 [95% CI 2.6-39.02]) and episiotomy (OR 4.2 [95% CI 1.2-14.16]). HIV co-infection and newborn female were near significance (p=0.081 and 0.075, respectively).

CONCLUSIONS

Invasive procedures as fetal scalp blood sampling or internal electrode and episiotomy increase vertical transmission of HCV, especially in patients with positive HCV RNA virus load at delivery.

Hepatitis C Virus Sensing by Human Trophoblasts Induces Innate Immune Responses and Recruitment of Maternal NK Cells: Potential Implications for Limiting Vertical Transmission

Hepatitis C virus (HCV) is the world's most common blood-borne viral infection for which there is no vaccine. The rates of vertical transmission range between 3 and 6% with odds 90% higher in the presence of HIV coinfection. Prevention of vertical transmission is not possible because of lack of an approved therapy for use in pregnancy or an effective vaccine. Recently, HCV has been identified as an independent risk factor for preterm delivery, perinatal mortality, and other complications. In this study, we characterized the immune responses that contribute to the control of viral infection at the maternal-fetal interface (MFI) in the early gestational stages. In this study, we show that primary human trophoblast cells and an extravillous trophoblast cell line (HTR8), from first and second trimester of pregnancy, express receptors relevant for HCV binding/entry and are permissive for HCV uptake. We found that HCV-RNA sensing by human trophoblast cells induces robust upregulation of type I/III IFNs and secretion of multiple chemokines that elicit recruitment and activation of decidual NK cells. Furthermore, we observed that HCV-RNA transfection induces a proapoptotic response within HTR8 that could affect the morphology of the placenta. To our knowledge, for the first time, we demonstrate that HCV-RNA sensing by human trophoblast cells elicits a strong antiviral response that alters the recruitment and activation of innate immune cells at the MFI. This work provides a paradigm shift in our understanding of HCV-specific immunity at the MFI as well as novel insights into mechanisms that limit vertical transmission but may paradoxically lead to virus-related pregnancy complications.

Vertical hepatitis C virus transmission: Main questions and answers

Hepatitis C virus (HCV) affects about 3% of the world’s population and peaks in subjects aged over 40 years. Its prevalence in pregnant women is low (1%-2%) in most western countries but drastically increases in women in developing countries or with high risk behaviors for blood-transmitted infections. Here we review clinical, prognostic and therapeutic aspects of HCV infection in pregnant women and their offspring infected through vertical transmission. Pregnancy-related immune weakness does not seem to affect the course of acute hepatitis C but can affect the progression of chronic hepatitis C. In fact, postpartum immune restoration can exacerbate hepatic inflammation, thereby worsening the liver disease, particularly in patients with liver cirrhosis. HCV infection increases the risk of gestational diabetes in patients with excessive weight gain, premature rupture of membrane and caesarean delivery. Only 3%-5% of infants born to HCV-positive mothers have been infected by intrauterine or perinatal transmission. Maternal viral load, human immunodeficiency virus coinfection, prolonged rupture of membranes, fetal exposure to maternal infected blood consequent to vaginal or perineal lacerations and invasive monitoring of fetus increase the risk of viral transmission. Cesarean delivery and breastfeeding increases the transmission risk in HCV/human immunodeficiency virus coinfected women. The consensus is not to offer antiviral therapy to HCV-infected pregnant women because it is based on ribavirin (pregnancy category X) because of its embryocidal and teratogenic effects in animal species. In vertically infected children, chronic C hepatitis is often associated with minimal or mild liver disease and progression to liver cirrhosis and hepatocarcinoma is lower than in adults. Infected children may be treated after the second year of life, given the adverse effects of current antiviral agents.

Gender specific medicine in liver diseases: A point of view

Gender medicine focuses on the patho-physiological, clinical, prevention and treatment differences in diseases that are equally represented in men and women. The purpose of gender medicine is to ensure that each individual man and woman receives the best treatment possible based on scientific evidence. The concept of “gender” includes not only the sexual characteristics of individuals but also physiological and psychological attributes of men and women, including risk factors, protective/aggravating effects of sexual hormones and variances linked to genetics and corporal structures that explain biological and physiological differences between men and women. It is very important to consider all the biological, physiological, functional, psychological, social and cultural characteristics to provide patients with individualized disease management. Herein, we critically analyze the literature regarding gender differences for diseases and acquired conditions of the most representative hepatic pathologies: primary biliary cirrhosis, autoimmune hepatitis, primary sclerosing cholangitis, non alcoholic fatty liver disease and alcoholic liver disease, and viral chronic hepatitis B and C. The last section addresses hemochromatosis, which is a prevalent iron overload disorder in the Caucasian population. This review aims to describe data from the literature concerning viral chronic hepatitis during pregnancy, management during pregnancy and delivery, and new effective drugs for the prevention of maternal infection transmission without significant adverse effects or complications.

Maternal-fetal transmission of hepatitis C infection: what is so special about babies?

Children with hepatitis C virus infection often differ from adults regarding the rate of viral clearance, duration of infection, and the progression to cirrhosis. In the pediatric population, vertical transmission of hepatitis C virus infection from mother to infant is the most common route of infection. In the present review, we explore the factors that may influence the natural history of hepatitis C virus infection in children who acquire the infection through maternal-fetal transmission. There is particular focus on how viral diversity and the infant immune system may affect viral transmission. An enhanced understanding of maternal-fetal transmission of hepatitis C virus infection has the potential to affect effective drug and vaccine development for both children and adults.

Variation of transaminases, HCV-RNA levels and Th1/Th2 cytokine production during the post-partum period in pregnant women with chronic hepatitis C

This study analyses the evolution of liver disease in women with chronic hepatitis C during the third trimester of pregnancy and the post-partum period, as a natural model of immune modulation and reconstitution. Of the 122 mothers recruited to this study, 89 were HCV-RNA+ve/HIV-ve and 33 were HCV-RNA-ve/HIV-ve/HCVantibody+ve and all were tested during the third trimester of pregnancy, at delivery and post-delivery. The HCV-RNA+ve mothers were categorized as either Type-A (66%), with an increase in ALT levels in the post-partum period (>40 U/L; P<0.001) or as Type-B (34%), with no variation in ALT values. The Type-A mothers also presented a significant decrease in serum HCV-RNA levels in the post-delivery period (P<0.001) and this event was concomitant with an increase in Th1 cytokine levels (INFγ, P = 0.04; IL12, P = 0.01 and IL2, P = 0.01). On the other hand, the Type-B mothers and the HCV-RNA-ve women presented no variations in either of these parameters. However, they did present higher Th1 cytokine levels in the partum period (INFγ and IL2, P<0.05) than both the Type-A and the HCV-RNA-ve women. Cytokine levels at the moment of delivery do not constitute a risk factor associated with HCV vertical transmission. It is concluded that differences in the ALT and HCV-RNA values observed in HCV-RNA+ve women in the postpartum period might be due to different ratios of Th1 cytokine production. In the Type-B women, the high partum levels of Th1 cytokines and the absence of post-partum variation in ALT and HCV-RNA levels may be related to permanent Th1 cytokine stimulation.

Pathogenesis of hepatitis C during pregnancy and childhood

The worldwide prevalence of HCV infection is between 1% and 8% in pregnant women and between 0.05% and 5% in children. Yet the pathogenesis of hepatitis C during pregnancy and in the neonatal period remains poorly understood. Mother-to-child transmission (MTCT), a leading cause of pediatric HCV infection, takes place at a rate of <10%. Factors that increase the risk of MTCT include high maternal HCV viral load and coinfection with HIV-1 but, intriguingly, not breastfeeding and mode of delivery. Pharmacological prevention of MTCT is not possible at the present time because both pegylated interferon alfa and ribavirin are contraindicated for use in pregnancy and during the neonatal period. However, this may change with the recent introduction of direct acting antiviral agents. This review summarizes what is currently known about HCV infection during pregnancy and childhood. Particular emphasis is placed on how pregnancy-associated immune modulation may influence the progression of HCV disease and impact MTCT, and on the differential evolution of perinatally acquired HCV infection in children. Taken together, these developments provide insights into the pathogenesis of hepatitis C and may inform strategies to prevent the transmission of HCV from mother to child.

Prophylaxis for ribavirin-related anemia using eicosapentaenoic acid in chronic hepatitis C patients

BACKGROUND

Ribavirin-related anemia is a serious side-effect of the pegylated interferon and ribavirin therapy used for hepatitis C, and may be cause for a reduction in ribavirin dose or even cessation of treatment. The aim of this study was to evaluate the prophylactic effects of oral eicosapentaenoic acid (EPA) supplementation on ribavirin-induced hemolytic anemia in pediatric and young adult patients.

METHODS

Twelve chronic hepatitis C patients ranging in age from 3 to 21 years (mean, 13.9 ± 5.1 years) who received pegylated interferon α-2b and ribavirin combination therapy were randomized to either the control group (n = 6) or EPA group (n = 6). Blood samples were collected before, and at 4, 8, and 16 weeks after treatment to measure clinical laboratory parameters.

RESULTS

The reduction in hemoglobin levels of the EPA group was significantly ameliorated at 8 and 16 weeks when compared to the control group (P < 0.05). There was no significant difference in plasma ribavirin concentrations between the two groups during the treatment. However, one patient in the control group had a reduction in ribavirin dose.

CONCLUSION

EPA supplementation prevented ribavirin-induced hemolytic anemia during combination therapy with pegylated interferon α-2b and ribavirin in pediatric and young adult patients.

Risk factors for mother-to-child transmission of hepatitis C virus: Maternal high viral load and fetal exposure in the birth canal

AIM

  Mother-to-child transmission (MTCT) is the major transmission pathway of hepatitis C virus (HCV) in children. However, its risk factors remain unsettled for introduction of putative intervention.

METHODS

  Pregnant women screened for HCV and MTCT in children born to antibody-positive mothers were prospectively studied in Tottori, Japan.

RESULTS

  Among 41 856 screened women, 188 (0.45%) were HCV antibody-positive, of whom 61% had detectable HCV RNA. While 10 of the 34 children (29%) born to high viral load (HVL: ≥6.0 × 10(5)  IU/mL) mothers were infected, none born to RNA-detectable but non-HVL mothers were infected (P < 0.001). MTCT among vaginally delivered children born to HVL mothers was analyzed. Children delivered after 4 h or more of labor were more frequently infected than were those born within 4 h of labor (P = 0.019). Premature rupture of fetal membranes was significantly more common in infected children than in uninfected children (P < 0.001). Durations of membrane rupture and labor were longer in infected children than in uninfected children (P = 0.008 and P = 0.040, respectively). Elective cesarean section that eliminates these risk factors, other than HVL, significantly reduced MTCT from nine of 22 (41%) to none of nine children (0%) (P = 0.032).

CONCLUSION

  Our data suggest that contamination of the fetus in the birth canal with infected maternal blood is a major risk factor for HCV MTCT, in addition to maternal HVL. To rationalize intervention by elective cesarean section, the natural history of infected children should be carefully evaluated.

Genetic variation in interleukin 28B with respect to vertical transmission of hepatitis C virus and spontaneous clearance in HCV-infected children

The vertical transmission of hepatitis C virus (HCV-VT) is a major route of HCV infection in children, but the risk factors remain incompletely understood. This study analyzed the role of interleukin 28B (IL28B) in HCV-VT and in the spontaneous clearance of HCV among infected infants. Between 1991 and 2009, 145 mothers were recruited for this study: 100 were HCV-RNA+ve / human immunodeficiency virus negative (HIV-ve), with 128 children, and 33 were HCV-RNA-ve/HCV antibody+ve, with 43 children. The infants were tested for HCV-RNA at birth and at regular intervals until the age of 6 years. IL28B (single nucleotide polymorphism rs12979860) was determined in the mothers and children. HCV-VT was assumed when children presented HCV-RNA+ve in two subsequent blood samples. HCV-VT-infected infants were categorized as: (1) transient viremia with posterior HCV-RNA-ve and without serum-conversion; (2) persistent infection with serum-conversion. Of the 31 mothers with CC polymorphism, 19 (61%) were HCV-RNA+ve, whereas among the 68 mothers with non-CC polymorphism, 56 (82%) were HCV-RNA+ve. In all, 26 of 128 (20%) infants born to the HCV-RNA+ve mothers acquired HCV infection, but only 9 (7%) were chronically infected. The rate of HCV-VT was higher among the mothers with higher HCV viremia. No HCV-VT was detected in the HCV-RNA-ve women. Neither the mothers' nor the childrens' IL-28 status was associated with an increased risk of HCV-VT. The factors influencing viral clearance among the infected children were genotype non-1 and genotype CC of IL28B. In logistic regression, child CC polymorphism was the only predictor of HCV-clearance in HCV genotype-1.

CONCLUSION

High maternal viral load is the only predictive factor of HCV-VT. IL28B plays no role in HCV-VT, but IL28B CC child polymorphism is associated independently with the spontaneous clearance of HCV genotype-1 among infected children.

Innate immune function in placenta and cord blood of hepatitis C--seropositive mother-infant dyads

Vertical transmission accounts for the majority of pediatric cases of hepatitis C viral (HCV) infection. In contrast to the adult population who develop persistent viremia in approximately 80% of cases following exposure, the rate of mother-to-child transmission (2-6%) is strikingly low. Protection from vertical transmission likely requires the coordination of multiple components of the immune system. Placenta and decidua provide a direct connection between mother and infant. We hypothesized that innate immune responses would differ across the three compartments (decidua, placenta and cord blood) and that hepatitis C exposure would modify innate immunity in these tissues. The study was comprised of HCV-infected and healthy control mother and infant pairs from whom cord blood, placenta and decidua were collected with isolation of mononuclear cells. Multiparameter flow cytometry was performed to assess the phenotype, intracellular cytokine production and cytotoxicity of the cells. In keeping with a model where the maternal-fetal interface provides antiviral protection, we found a gradient in proportional frequencies of NKT and gammadelta-T cells being higher in placenta than cord blood. Cytotoxicity of NK and NKT cells was enhanced in placenta and placental NKT cytotoxicity was further increased by HCV infection. HCV exposure had multiple effects on innate cells including a decrease in activation markers (CD69, TRAIL and NKp44) on NK cells and a decrease in plasmacytoid dendritic cells in both placenta and cord blood of exposed infants. In summary, the placenta represents an active innate immunological organ that provides antiviral protection against HCV transmission in the majority of cases; the increased incidence in preterm labor previously described in HCV-seropositive mothers may be related to enhanced cytotoxicity of NKT cells.

Innate immune function in placenta and cord blood of hepatitis C--seropositive mother-infant dyads

Vertical transmission accounts for the majority of pediatric cases of hepatitis C viral (HCV) infection. In contrast to the adult population who develop persistent viremia in ∼80% of cases following exposure, the rate of mother-to-child transmission (2–6%) is strikingly low. Protection from vertical transmission likely requires the coordination of multiple components of the immune system. Placenta and decidua provide a direct connection between mother and infant. We hypothesized that innate immune responses would differ across the three compartments (decidua, placenta and cord blood) and that hepatitis C exposure would modify innate immunity in these tissues. The study was comprised of HCV-infected and healthy control mother and infant pairs from whom cord blood, placenta and decidua were collected with isolation of mononuclear cells. Multiparameter flow cytometry was performed to assess the phenotype, intracellular cytokine production and cytotoxicity of the cells. In keeping with a model where the maternal-fetal interface provides antiviral protection, we found a gradient in proportional frequencies of NKT and γδ-T cells being higher in placenta than cord blood. Cytotoxicity of NK and NKT cells was enhanced in placenta and placental NKT cytotoxicity was further increased by HCV infection. HCV exposure had multiple effects on innate cells including a decrease in activation markers (CD69, TRAIL and NKp44) on NK cells and a decrease in plasmacytoid dendritic cells in both placenta and cord blood of exposed infants. In summary, the placenta represents an active innate immunological organ that provides antiviral protection against HCV transmission in the majority of cases; the increased incidence in preterm labor previously described in HCV-seropositive mothers may be related to enhanced cytotoxicity of NKT cells.

Innate immune function in placenta and cord blood of hepatitis C--seropositive mother-infant dyads

Vertical transmission accounts for the majority of pediatric cases of hepatitis C viral (HCV) infection. In contrast to the adult population who develop persistent viremia in approximately 80% of cases following exposure, the rate of mother-to-child transmission (2-6%) is strikingly low. Protection from vertical transmission likely requires the coordination of multiple components of the immune system. Placenta and decidua provide a direct connection between mother and infant. We hypothesized that innate immune responses would differ across the three compartments (decidua, placenta and cord blood) and that hepatitis C exposure would modify innate immunity in these tissues. The study was comprised of HCV-infected and healthy control mother and infant pairs from whom cord blood, placenta and decidua were collected with isolation of mononuclear cells. Multiparameter flow cytometry was performed to assess the phenotype, intracellular cytokine production and cytotoxicity of the cells. In keeping with a model where the maternal-fetal interface provides antiviral protection, we found a gradient in proportional frequencies of NKT and gammadelta-T cells being higher in placenta than cord blood. Cytotoxicity of NK and NKT cells was enhanced in placenta and placental NKT cytotoxicity was further increased by HCV infection. HCV exposure had multiple effects on innate cells including a decrease in activation markers (CD69, TRAIL and NKp44) on NK cells and a decrease in plasmacytoid dendritic cells in both placenta and cord blood of exposed infants. In summary, the placenta represents an active innate immunological organ that provides antiviral protection against HCV transmission in the majority of cases; the increased incidence in preterm labor previously described in HCV-seropositive mothers may be related to enhanced cytotoxicity of NKT cells.

Perinatal transmission of hepatitis C virus infection

In industrialized countries, hepatitis C virus (HCV) is the most common cause of chronic liver disease in children. Perinatal transmission is the leading cause of infection. Perinatal transmission is confined almost always to women with detectable HCV ribonucleic acid (RNA) in the peripheral blood by the polymerase chain reaction but all children born to women with anti-HCV antibodies should be tested for HCV. Some but not all studies found that a high concentration of serum HCV RNA is associated with a higher risk of transmission. Maternal peripheral blood mononuclear cell infection by HCV, membrane rupture of longer than 6 hr before delivery, and procedures exposing the infant to maternal blood infected with HCV during vaginal delivery are associated with an increased risk of transmission. Maternal coinfection with HCV and human immunodeficiency virus, maternal history of intravenous drug use and of HCV infection of the sexual partner of the mother predict the risk of perinatal transmission and are dependent on the peripheral blood mononuclear cell infection by HCV. Delivery by Cesarean section is not recommended in pregnant women infected with HCV. Infected mothers can breast feed safely their infants if the nipples are not damaged. A previous delivery of a child infected perinatally with HCV does not increase the risk of transmission in subsequent pregnancies. Immunogenetic factors and HCV genotypes are not related to HCV perinatal transmission. Despite an increased understanding of the risk factors involved in perinatal transmission of HCV, to date little is known about the transmission mechanisms and timing.