Natural history of perinatal hepatitis C virus infection

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.

Vertically acquired hepatitis C virus infection: Correlates of transmission and disease progression

The worldwide prevalence of hepatitis C virus (HCV) infection in children is 0.05%-0.4% in developed countries and 2%-5% in resource-limited settings, where inadequately tested blood products or un-sterile medical injections still remain important routes of infection. After the screening of blood donors, mother-to-child transmission (MTCT) of HCV has become the leading cause of pediatric infection, at a rate of 5%. Maternal HIV co-infection is a significant risk factor for MTCT and anti-HIV therapy during pregnancy seemingly can reduce the transmission rate of both viruses. Conversely, a high maternal viral load is an important, but not preventable risk factor, because at present no anti-HCV treatment can be administered to pregnant women to block viral replication. Caution is needed in adopting obstetric procedures, such as amniocentesis or internal fetal monitoring, that can favor fetal exposure to HCV contaminated maternal blood, though evidence is lacking on the real risk of single obstetric practices. Mode of delivery and type of feeding do not represent significant risk factors for MTCT. Therefore, there is no reason to offer elective caesarean section or discourage breast-feeding to HCV infected parturients. Information on the natural history of vertical HCV infection is limited. The primary infection is asymptomatic in infants. At least one quarter of infected children shows a spontaneous viral clearance (SVC) that usually occurs within 6 years of life. IL-28B polymorphims and genotype 3 infection have been associated with greater chances of SVC. In general, HCV progression is mild or moderate in children with chronic infection who grow regularly, though cases with marked liver fibrosis or hepatic failure have been described. Non-organ specific autoantibodies and cryoglobulins are frequently found in children with chronic infection, but autoimmune diseases or HCV associated extrahepatic manifestations are rare.

Biomarkers in HCV Infection

Liver-related biomarkers have been developed and validated mainly in patients with chronic hepatitis C for the prediction of liver fibrosis or cirrhosis, which is a final pathway of chronic liver injury. They are noninvasive, traceable, and easy-to-use. Biomarkers provide implications related to screening, diagnosis, treatment, and prognosis of chronic hepatitis. For the improvement of performance and coverage, biomarker panels, imaging biomarkers, and even genetic biomarkers have been developed. With the advancement of genomics and proteomics, earlier and more precise prediction is expected in the near future. In this review, multiple biomarker panels for the estimation of the degree of fibrosis in chronic hepatitis C, biomarkers for the screening and diagnosis of hepatitis C, biomarkers for the treatment of hepatitis C, biomarkers for the prediction of complications related to the chronic hepatitis C, and future perspectives will be summarized.

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.

Vertical transmission of hepatitis C virus: a tale of multiple outcomes

Globally, hepatitis C virus (HCV) infection affects approximately 130 million people and 3 million new infections occur annually. HCV is also recognized as an important cause of chronic liver disease in children. The absence of proofreading properties of the HCV RNA polymerase leads to a highly error prone replication process, allowing HCV to escape host immune response. The adaptive nature of HCV evolution dictates the outcome of the disease in many ways. Here, we investigated the molecular evolution of HCV in three unrelated children who acquired chronic HCV infection as a result of mother-to-child transmission, two of whom were also coinfected with HIV-1. The persistence of discrete HCV variants and their population structure were assessed using median joining network and Bayesian approaches. While patterns of viral evolution clearly differed between subjects, immune system dysfunction related to HIV coinfection or persistent HCV seronegativity stand as potential mechanisms to explain the lack of molecular evolution observed in these three cases. In contrast, treatment of HCV infection with PegIFN, which did not lead to sustained virologic responses in all 3 cases, was not associated with commensurate variations in the complexity of the variant spectrum. Finally, the differences in the degree of divergence suggest that the mode of transmission of the virus was not the main factor driving viral evolution.

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.

Spontaneous clearance of hepatitis C virus in vertically infected children

Spontaneous viral clearance of hepatitis C virus (HCV) has been reported to occur in children with vertical HCV infection. However, factors which are associated with or predispose for clearance are largely unknown. In this case series we retrospectively analyzed laboratory parameters associated with spontaneous clearance of HCV in vertically infected children. The charts of six patients with documented spontaneous viral clearance by the age of 5 years were reviewed regarding clinical course, liver function tests (LFTs) and trend of HCV gene copy numbers. Spontaneous viral elimination was observed between the 25th and 52nd months of age. All patients had elevated LFTs, which peaked before 20 months of life. Peak LFT elevation was followed by normalization of LFTs and decline in viral load. These findings suggest that, in vertically HCV-infected children, a potent inflammatory response in the liver precedes viral clearance. Therefore, temporarily elevated LFTs, followed by a decline of viral load may be indicative of a near viral clearance in early childhood.

CONCLUSION

Further investigations regarding the development of optimal treatment algorithms should take into account factors, which are associated with possible spontaneous viral resolution, such as viral genotype, favourable host factors as well as direct and indirect parameters of antiviral immunity, and the individual course of viral replication.

The impact of mode of acquisition on biological markers of paediatric hepatitis C virus infection

Despite the introduction of blood donor screening, worldwide, children continue to become infected with hepatitis C virus (HCV) via un-sterile medical injections, receipt of unscreened blood and isolated hospital contamination outbreaks. It is plausible that the natural history and disease progression in these children might differ from that of their vertically infected counterparts. Vertically and parenterally HCV-infected children were prospectively followed within the European Paediatric HCV Network and the UK National HCV Register, respectively. Biological profiles were compared. Vertically and parenterally HCV-infected children differed in terms of some key characteristics including the male to female ratio and the proportion of children receiving therapy. Parenterally infected children were more likely to have at least one hepatomegaly event during follow-up, 20%vs 10%. Parenteral infection did not significantly affect the odds of being consistently viraemic (AOR 1.14, P = 0.703) and there was no significant difference in the odds of having consistently elevated ALT levels and mode of acquisition (AOR 0.83, P = 0.748). The proportion of children with 2 or more markers of HCV infection did not differ significantly by mode of acquisition (χ(2) 1.13, P = 0.288). This analysis does not support substantial differences between vertically and parenterally infected groups, but there are specific mechanisms identified requiring further investigation. Given the continued parenteral infection of children worldwide, it is vital that knowledge of disease progression in this group is accurate and that the differences in comparison with vertically infected children are clarified to inform more accurate and individualized clinical management.

Hepatitis C virus infection during pregnancy and the newborn period--are they opportunities for treatment?

The worldwide prevalence of hepatitis C virus (HCV) infection in pregnant women is estimated to be between 1 and 8% and in children between 0.05% and 5%. While parenteral transmission is still common in children living in developing countries, perinatal transmission is now the leading cause of HCV transmission in developed countries. The absence of an HCV vaccine or approved therapy during pregnancy means that prevention of vertical transmission is still not possible. However, a low vertical transmission rate of 3-5%, a high rate of spontaneous clearance (25-50%) and delayed morbidity have resulted in HCV being overlooked in pregnant women and their infants. Yet a study of the natural history in mothers and children demonstrates that the prognosis of HCV can vary greatly and should be taken seriously. Factors known to increase the risk of perinatal transmission include HIV coinfection and higher maternal viral loads, while elective C-section and withholding breastfeeding have not been demonstrated to reduce vertical transmission. Current guidelines for the diagnosis of persistent perinatal infection require a positive anti-HCV test in infants born to infected mothers after 12 months or two positive HCV RNA tests at least 6 months apart. Current HCV treatment options using pegylated interferon and ribavirin are both unsuitable for use in pregnancy and infancy. However, new agents currently in preclinical phases of development, along with the recently identified association between single-nucleotide polymorphisms within the IL28 gene and treatment response, may serve to create a therapeutic window for these patients.

Chronic hepatitis C virus infection in children

The importance of hepatitis C viral infection in the health care of children has grown in recent decades. More is now known about the epidemiology of this infection in children and the progression of disease in the pediatric age group, and the treatment options are increasing. In this review, we update readers on the state of our understanding of hepatitis C infection in children, provide the current recommendations for monitoring and treatment, and discuss emerging therapies.

Hepatitis C in children

Mother-to-child, or vertical transmission, of hepatitis C virus is now the dominant mode of acquisition of infection for children. The rate of transmission is low in women who are not also HIV-positive. Whether the mode of delivery is associated with transmission remains questionable; breast-feeding does not appear to be a source of infection. The detection of hepatitis C virus RNA using the polymerase chain reaction is a sensitive method for the early diagnosis of infection in perinatally exposed infants, but false positive results can occur. The natural history of hepatitis C virus infection in children is not well defined, but chronic infection is common in most cases. The disease progression is slower than in adults. Therapeutic trials (not placebo controlled) in a small number of children suggested a sustained response to interferon treatment in only a minority of cases. The option of combination therapy with ribavirin looks promising and needs evaluation.

Perinatal hepatitis C virus infection: diagnosis and management

Hepatitis C virus (HCV) infection in children is becoming an increasing challenge to health professionals. As our understanding of the disease evolves, so must our diagnostic and management strategies. In the 1990s, when HCV testing became available, children identified with HCV infection in the UK were mostly those who had required blood products, particularly those with haematological disorders. Acquiring knowledge of the natural history of HCV infection was confounded by the co-morbidity of iron overload, viral co-infection, and chemotherapy.

Hepatitis B and C viruses in infants and young children

Advances during the past 20 years have led to a better understanding of the prevention, diagnosis, and treatment of acute and chronic hepatitis B (HBV) and hepatitis C (HCV) infections in the pediatric population. Universal vaccination and prenatal testing for HBV have decreased the incidence rate of acute HBV infections from more than 3/100,000 to 0.34/100,000 in all children. Diagnosis of chronic HBV is confirmed with positive serologic testing on two occasions at least 6 months apart. Current approved therapies with interferon alpha and lamivudine for children with chronic HBV infection have shown some efficacy, but results have been variable. In contrast, the lack of an effective HCV vaccine and the risk of mother-to-child transmission may increase the number of children with vertically acquired HCV that ultimately go on to develop liver fibrosis or cirrhosis. Diagnosis of HCV in the neonate should be postponed until after the child reaches 1 year of age because infants may have transient viremia. Treatment for HCV infected children has not been studied extensively. Peginterferon alpha-2a and Ribavirin are not currently approved for pediatric use; however, recent studies in children have shown potential benefit. More effective and less toxic therapies for young patients with HBV and HCV are needed, as are methods to interrupt perinatal transmission of HBV and HCV.

HCV infection in very-long-term survivors after cancer chemotherapy and bone marrow transplantation: a single-center experience

The long-term evolution of hepatitis C virus (HCV) infection in oncologic and/or transplanted patients is still unknown. Patients treated for cancer are different from the general HCV-infected population because of the immunosuppression and the hepatotoxic treatments, which act as co-factors of liver damage. Recently it was observed that antimetabolites play a role in accelerating the process of hepatic fibrosis. The aims of this retrospective study were to describe the clinical course of chronic hepatitis C acquired during anticancer treatment in a group of patients referred to a single center, and to correlate the course of hepatic disease to the type of treatment they received. Among the 17 children who underwent very long follow-up (range 10-18.5 years), the authors identified a group with more active hepatic cytolysis through the serial observation of mean ALT values, HCV RNA determination, and histologic data when available. During follow-up, none of them developed hepatic failure, cirrhosis, or hepatocarcinoma. No single risk factor, such as exposure to antimetabolites, alkylating agents, or other chemotherapy, radiotherapy to the abdomen, exposure to other hepatotoxic drugs, appearance of vaso-occlusive disease, acute and/or chronic graft-versus-host disease, or length of immunosuppression, correlated with a worse course of hepatitis. No definitive conclusions can be drawn. However, multivariate analysis of hepatic risk factors in larger cohorts of patients will be able to provide us with more precise information about the clinical outcome of chronic hepatitis in survivors.

Long-term outcome of vertically acquired and post-transfusion hepatitis C infection in children

BACKGROUND AND AIM

To determine the natural history of perinatally acquired hepatitis C virus (HCV) infection, clinical and laboratory outcomes among 31 children with HCV infection were retrospectively reviewed. Fifteen children had acquired HCV by blood transfusion (BT) prior to 6 months of age and 16 had vertically acquired (VT) HCV.

METHODS

Demographic data, clinical symptoms and signs, liver biochemistry, HCV antibody, HCV-RNA and liver histology were evaluated.

RESULTS

Mean age at last visit was 13.0 years (range 9.0-16.8 years) in the BT group and 8.6 years (range 0.5-18.1 years) in the VT group. There were no abnormal clinical findings of chronic liver disease in either group. Estimated HCV-RNA clearance rate was 19%, with no significant difference between the groups. In HCV-RNA-negative children (n = 6), two lost anti-HCV antibody and two developed indeterminate anti-HCV antibody results, while all HCV-RNA-positive children (n = 25) remained both anti-HCV antibody positive and HCV-RNA positive throughout follow up. The alanine aminotransferase level was significantly higher in the VT group than in the BT group during the first 5 years of life. Liver biopsy, which was carried out in four children, revealed mild to moderate fibrosis and/or necroinflammatory activity, but no cirrhosis.

CONCLUSIONS

Outcomes among children with HCV acquired in infancy demonstrate asymptomatic and slowly progressive disease, at least for the initial decade of infection. Mode of acquisition appears to have a limited impact on outcomes, with similar viral clearance and anti-HCV antibody seroreversion rates in vertical and transfusion acquired infection.

Treatment of chronic hepatitis C in children

Since the discovery of hepatitis C virus (HCV) in 1989, significant advances have been made in our understanding of this important viral pathogen. Children at risk for HCV infection include recipients of potentially contaminated blood products and organ transplants, and infants born to HCV-infected mothers. Chronic HCV infection is usually asymptomatic in children but active hepatitis, cirrhosis and hepatocellular carcinoma can occur. The development of treatment strategies for chronic hepatitis C in children has directly evolved from clinical trials in adults. Sustained virologic response, defined by undetectable HCV RNA in serum 24 wk after completion of treatment, occurs in approximately 36% of children treated with conventional interferon alone and in about 50% of those given conventional interferon in combination with ribavirin. Pegylated interferon-based treatment regimens are better than those based on conventional interferon in adults but little is known about pegylated interferon in children. Factors associated with a favorable response to antiviral therapy in children are similar to those in adults and include infection with HCV genotype 2 or 3 and low pretreatment serum HCV RNA levels. Treatment related adverse events in children include 'flu-like' syndrome, fatigue, anorexia, weight loss, depression, anemia, leukopenia and thrombocytopenia.

Combination therapy with ribavirin and interferon in a cohort of children with hepatitis C and haemophilia followed at a pediatric haemophilia treatment center

Nearly all children with bleeding disorders who received factor concentrates prior to the late 1980s were infected with hepatitis C. Treatment of adults infected with hepatitis C with combination therapy consisting of ribavirin and interferon has shown sustained response rates of 30-60%. Little data is available on the response of children infected with hepatitis C treated with combination therapy, especially those with bleeding disorders. We wish to report a single paediatric haemophilia treatment center's results of treatment of adolescents with haemophilia and hepatitis C infection with combination therapy. All patients followed at the haemophilia treatment center with hepatitis C, who were human immunodeficiency virus (HIV) negative and had a measurable hepatitis C viral load were eligible. Study patients received at least 6 months of 3 MU interferon-alpha via subcutaneous injection three times per week and 1000 mg day(-1) of ribavirin. Eleven patients agreed to participate in the study. Three patients had an un measurable viral load after 6 months of combination therapy. All three completed 12 months of medication and continued to remain free of hepatitis C for 12 months after discontinuation of therapy. Side-effects of combination therapy were significant but tolerable. The sustained response rate in this study is similar to the historical response rate seen in adults but less than the other reported response rates seen in children treated with combination therapy. Given the toxicity of combination therapy, and natural history of hepatitis C infection in children, consideration of a liver biopsy to evaluate disease progression prior to considering antiviral medications is warranted.

Clinical features and progression of perinatally acquired hepatitis C virus infection

The purpose of this prospective-retrospective study was to provide information about the clinical features and progression of hepatitis C virus (HCV) infection transmitted perinatally. Seventy children born to HCV infected woman were enrolled consecutively in five European centers between 1990 and 1999, provided they had HCV RNA in the serum during the first year of life and/or were still anti-HCV positive at 18 months. Sixty-two infants were followed up to 24 months of age or more (range, 24 months-11 years; average, 4.8 +/- 2.3 years). A wide range of ALT elevation was observed in 93% of the infants in the first year of life. During the follow-up, a sustained ALT normalization with loss of HCV RNA was seen in 12/62 (19%) of the children within 30 months of life; 66% of the infants had developed an ALT peak greater than 5x normal at onset (vs. 28% of children with persistent viremia; P < 0.05), and 50% had HCV genotype 3 (vs. 17% of viremic children). Conversely the cumulative probability of chronic progression was 81%. Chronic infection was asymptomatic and liver disease was mild in all 11 children who underwent a biopsy. In conclusion the early stage of acquired perinatally HCV infection is characterized by a wide range of ALT abnormalities, suggesting the interaction of multiple host and virus factors. The chronic progression rate of infection is high, but the associated liver disease is usually mild. High ALT levels at onset seem to offer greater opportunity of biochemical remission and loss of viremia during follow-up.

[Role of interferons in the treatment of hepatitis B and hepatitis C virus infections]

BACKGROUND

Since the discovery of hepatitis C (HCV), the efficacy of treatment has significantly progressed using standard mono-therapy: with Interferon alpha (IFN) during six months we obtained approximately 10% sustained response and currently with the association of pegylated IFN and Ribavirin a 55% sustained response was achieved.

CURRENT POSITION AND MAJOR POINTS

HCV infection continues to present therapeutic problems which have not entirely been solved, mainly related to clinical and biological tolerance, and non-responders. Moreover, the care of patients with extra-hepatic localization, cirrhotic patients, as well as therapeutic problems of co-infected HIV-HCV patients. As regards hepatitis B (HBV) new effective treatments against this virus have appeared, IFN then nucleoside analogs, some of which are available in France (i.e. lamivudine, adefovir, dipovoxil). The main objective of chronic hepatitis B treatment is to obtain the complete inhibition of the HBV virus by Hbe-antigen antibody seroconversion which would therefore significantly increase patient survival. In this article the advantages and disadvantages of the different treatments are assessed.

FUTURE PERSPECTIVES

Despite the considerable and rapid progress obtained in the therapeutic treatment of infection due to HCV and HBV a number of unknown factors remain, which warrants further trials, in particular to evaluate the efficacy as well as the tolerance of the antiviral agent association.

Breast milk transmission of viral disease

Breast milk transmission of maternal viral infection is well established for CMV and HIV-1. In the case of CMV, this usually does not pose a risk to the infant since serious disease is prevented by placentally transferred maternal antibody. However, in HIV infection, breast-feeding increases the risk of maternal-fetal transmission by about 25% with late breast-feeding (after six months of age) constituting a particular risk. In other maternal viral diseases, e.g., other herpes viruses, parvovirus, hepatitis A, B and C, and rubella, the virus is often demonstrated in the breast milk, but transmission is very rare. The highest risk is during an acute viral infection at the time of birth, since the breast milk has a high titer of virus, and a lack of antibody to neutralize the organism.

[Hepatitis C and pregnancy]

PURPOSE

Today, the natural course of hepatitis C virus (HCV) infection during pregnancy and the prevalence of mother-to-child transmission are better known.

CURRENT KNOWLEDGE AND KEY POINTS

Antenatal screening for HCV infection needs to be proposed to women with risk factors. Viral replication needs to be confirmed by PCR in pregnant women with antibodies against HCV. To date, the clinical course of pregnancy and the mode of delivery have not been changed by HCV infection. Rates of vertical transmission of HCV are about 6% in women with HCV alone and 15% in women co-infected with HIV. A screening for HCV markers is required 18 months after delivery for infants born to HCV mothers. Because of the relatively low rate of HCV vertical transmission, pregnancy can be allowed in infected women. However, taking into account the efficacy of new antiviral strategies, treatment of HCV infection could be proposed before pregnancy.

FUTURE PROSPECTS AND PROJECTS

In case of HCV infection, a careful follow-up of both mother and newborns is required. Long-term follow-up of infected infants is needed to assess the consequences of perinatal HCV infection.

Challenges in the treatment of hepatitis C in children

Hepatitis C infection in children is associated with a unique set of challenges for clinicians and investigators. Although the prevalence of HCV infection is lower in children than in adults, it is important to identify infected children to monitor progression of liver disease and to make appropriate interventions to minimize factors that may exacerbate progression. Identification requires understanding of risk factors important in children, primarily exposure at or near the time of birth. The natural history of this infection in most children is either more benign or significantly prolonged than that of infection acquired in adulthood. Reasons for this difference in natural history must be explored and possibly even exploited in the care of adult patients with HCV infection. Identification of appropriate pediatric candidates for treatment and definition of optimal therapy for these children require ongoing study. Lastly, as perinatal transmission becomes the primary mode of acquisition for new pediatric infections, factors that increase or decrease the likelihood of this transmission must be identified, and effective preventive interventions must be put into practice. There are important differences in the clinical features, natural history, and response to therapy between pediatric and adult patients with HCV infection. Understanding of these differences will allow optimal care for affected children and perhaps better understanding of the pathophysiology and pure natural history of this disease.

Evolution in the hypervariable region of hepatitis C virus in infants after vertical transmission

To elucidate the clonal evolution of hepatitis C virus (HCV) during mother-to-infant transmission, we prospectively analyzed HCV clones of the hypervariable region in four HCV RNA-positive infants and compared them with those of the mother. Cord blood samples from three of the four infants were positive for the HCV RNA (< or =10(3) copies/mL), and all of the four infants had the HCV RNA titer of >10(6) copies/mL within 2 mo after birth. The hypervariable region clones detected in the infants were closely related to those in the respective mothers. The results suggest the perinatal transmission of HCV. The hypervariable region clones transmitted to infants were not a single selected clone or minor clones in the mother. None of the clones specific to the low-density fraction in the mother was transmitted to the infants. Moreover, the proportion of HCV in the low-density fraction was minimal in the first few months of life, but increased several months after birth in association with the elevation of alanine aminotransferase. These results suggest that the increase of HCV in the low-density fraction reflect the evolution of immune response in infants. We also demonstrated that the emergence of quasispecies in infants precedes the infantile antibody response.

Detection of TT virus DNA and GB virus type C/Hepatitis G virus RNA in serum and breast milk: determination of mother-to-child transmission

To investigate the vertical transmission of the newly described TT virus (TTV), serum and breast milk samples from 46 women as well as sera from their 47 newborns were examined for the presence of TTV DNA by PCR. TTV DNA was detected in 47.8% (n = 22) of the women. All but one child born to these women were also viremic for TTV from the first sample onward. TTV DNA was found in 73.9% (n = 17) of the breast milk samples derived from TTV viremic mothers. The one TTV-negative child born to a viremic mother remained negative during follow-up, although it was breast-fed. Our data show that TTV is highly effectively transmitted from mothers to their children during pregnancy. Although the majority of breast milk samples from viremic mothers are positive by TTV PCR, there is no need to discourage women from breast-feeding, because most children are TTV viremic even before breast-feeding begins.

Hepatitis C virus infection in children

The prevalence of hepatitis C virus (HCV) infection is relatively low in childhood, with anti-HCV prevalence rates of 0.1-0.4% in the Western world. To date, blood transfusion has been the principal route of acquisition of HCV in children, but there is evidence that vertical transmission is overtaking it. The overall risk of vertical perinatal transmission of HCV is about 5%, although it increases with HIV co-infection and higher maternal viraemia. The mode of delivery and breastfeeding do not seem to affect the vertical transmission of HCV. Diagnosis of perinatal transmission relies on determination of ALT levels and the presence of HCV after the second month, while maternal anti-HCV antibodies may persist until 18 months of life. After infancy, a variable percentage of perinatally infected children are anti-HCV negative; thus, detection of HCV-RNA is necessary for accurate diagnosis. The natural history of HCV in childhood is not well understood and the outcome depends on host and viral factors. The rate of progression to chronicity is about 60-80% in both post-transfusion and vertically acquired HCV infection. Compared with adult patients, chronic hepatitis C in children is characterized by both low ALT levels and low viral load, as well as by the mildest histological and immunohistochemical forms of chronic hepatitis. The prognosis is usually worse in multitransfused, thalassaemic children and those who have had cancer. Experience of treatment of chronic hepatitis C in children is limited, with about 40% having a sustained response to the interferon therapy. It is necessary to perform long-term follow-up and multicentre treatment studies to improve knowledge of the natural history of HCV in children, as well as that of the efficacy of anti-viral therapy in childhood.

Clinical and histologic features of chronic hepatitis C virus infection after blood transfusion in Japanese children

OBJECTIVE

To characterize the clinical and histologic features of chronic hepatitis C virus (HCV) infection after blood transfusion in Japanese children.

STUDY DESIGN

We studied 231 children with a history of blood product transfusion. Patients were divided into two groups: 116 patients with a history of malignant disease (group 1), 115 patients who had undergone open heart surgery (group 2). We examined changes in serum alanine aminotransferase (ALT) activity and HCV markers, and patients' clinical course. Moreover, in 38 patients in whom the time of HCV infection could be defined, we examined liver histology.

RESULTS

The proportions of patients in each group who were anti-HCV-positive were 35 out of 116 (30%) and 20 out of 115 (17%), respectively. Of the anti-HCV-positive patients, the proportions of HCV RNA-positive patients in each group were 30 out of 35 (86%) and 12 out of 20 (60%), respectively. Levels of ALT activity in patients with HCV infection varied widely for several years after blood transfusion; thereafter ALT activity fell to <100 IU/L in 2 groups. Serum ALT activity in patients who were HCV RNA-negative became normal. With regard to liver histology, there were no differences in the grade of necroinflammation or stage of fibrosis in patients with different durations of infection or when patients were analyzed according to the presence or absence of malignant disease. Patients mostly had grade 2-4 inflammation and stage 1-2 fibrosis. Thus, chronic hepatitis C was a morphologically mild disease in most children in this study.

CONCLUSIONS

Sixty percent to 80% of children with HCV infection in this study developed chronic hepatitis C. However, examination of liver histology findings in children with chronic hepatitis C showed only mild changes.

Treatment of chronic hepatitis C in pediatric patients

Although HCV infection in children shares some clinical features with that in adults, it is clearly different in several ways. These differences may have important implications for treatment. Some differences, such as milder disease, less frequent extrahepatic manifestations, and fewer comorbid conditions causing progression, argue against aggressive treatment in childhood. Other factors, such as less severe liver disease, shorter disease duration, possibly higher rates of sustained virologic response, and better tolerance of IFN, may be reasons to pursue treatment before advanced hepatic injury occurs. Given the relatively small number of pediatric patients with HCV infection and the gaps in the current understanding of natural history and effects of therapy in these patients, treatment should be undertaken only in clinical trials, so that careful data collection and monitoring can define more precisely the safety and efficacy of IFN therapy in children.

[The pediatrician and hepatitis C virus]

The recognition that hepatitis C virus can be transmitted perinatally or through blood transfusions warrants particular attention by the pediatrician. This paper highlights the epidemiology, diagnosis, natural history and management of hepatitis C in infants and children.

Detection of hepatitis C virus RNA (HCV RNA) in amniotic fluid: a prospective study

BACKGROUND/AIMS

Mother-to-infant transmission of hepatitis C virus (HCV) has been reported, but the transmission route is unknown. The aim of our study was to detect HCV RNA in amniotic fluid of pregnant women seropositive for HCV.

METHODS

Twenty-two HCV seropositive women were included in the study (median age: 39 years). An amniocentesis was performed in all patients during the 4th month of pregnancy. Sixteen women also tested positive for HCV RNA in serum. The range of HCV RNA titers was 0.3 to 15.1x10(6) Eq/ml (Quantiplex HCV RNA 2.0 Assay, Chiron Diagnostics). Of these 16 viremic patients, four had an anterior placenta, ten had a posterior placenta and the position of the placenta was not determined in two cases. PCR (Amplicor HCV, Roche Diagnostics) was used to detect HCV RNA in the amniotic fluid. We also studied 11 HCV seronegative women as a control group.

RESULTS

In the viremic group (n = 16), HCV RNA was detected once in amniotic fluid. The positive specimen was collected from a patient with an HCV RNA serum value equal to 1.1x10(6) Eq/ml. The placenta was in an anterior position. A PCR inhibitor was detected in one case. No HCV RNA was detected in the amniotic fluid of six seropositive non-viremic patients, nor in the control group. Serum HCV RNA was negative in the ten children tested. The woman whose amniotic fluid contained HCV RNA was the mother of one of them.

CONCLUSIONS

HCV RNA detection in amniotic fluid is rarely positive. The anterior position of the placenta in the only positive detection cannot rule out contamination of the amniotic fluid during the transplacental amniocentesis.

Shift in the buoyant density of hepatitis C virus particles in infants infected by mother-to-infant transmission

BACKGROUND

Hepatitis C virus (HCV) particles in sera can be divided into two classes: low-density free particles and high-density immune complex particles. Previous studies have revealed that the clinical progression of HCV infection is closely associated with the occurrence of the former class, rather than the latter, in an experimental chimpanzee model and in HCV-infected adult cases.

METHODS

To verify this concept in infantile cases, we prospectively analysed HCV particle populations, fractionated according to buoyant density, in serum samples from five infants infected by mother-to-infant transmission.

RESULTS

In all five cases, HCV particles were predominantly high density at the age of one month. In four of five cases, low-density HCV particles became predominant in association with a decrease in maternally transmitted antibody levels. In one case, in which high serum levels of alanine aminotransferase persisted, low-density particles were predominant between the ages of 3 and 9 months, in three consecutive samples. In other cases, in which infants were asymptomatic or had transient hepatitis, low-density HCV particles were predominant at only one sampling point or not at all throughout the follow-up period.

CONCLUSIONS

Maternal antibody transmitted via the placenta reacts with the HCV particles in infants infected through vertical transmission. A decrease in maternal antibody levels results in an increase in low-density free virions. It is suggested that low-density particles play an important role in liver inflammation.

Risk of hepatitis C infection in neonates transfused with blood from donors infected with hepatitis C

This look-back study was undertaken to identify newborn infants who had been infected with the hepatitis C virus (HCV) as a result of transfusions received before the introduction of routine screening in 1991 and to determine the transmission rates and persistence of transfusion-transmitted HCV infection acquired in the neonatal period. A total of 24 infants, transfused between 1980 and 1991, were identified as having received potentially infected blood from 11 blood donors. Ten of the donors had been administered batches of anti-D in 1977 known to have transmitted HCV genotype 1b infection. HCV RNA was detected in five of these donors when tested in 1994-95; the past donations of five of the donors, who had received anti-D immunoglobulin and had serological evidence of previous HCV infection but who were PCR negative when tested in 1994-95, were considered of lower risk. The source and time of acquisition of HCV infection for the one remaining donor in the study was not determined. Twenty-one (88%) of the 24 children were living at time of lookback. The median age at transfusion was 12 days. The median age at time of testing was 6.3 years. One child, who tested negative, was excluded from further analysis of HCV transmission, due to incomplete transfusion records. Overall, 12 of 20 (60%) children tested were positive for anti-HCV and seven (35%) were HCV RNA positive. Twelve (71%) of the 17 recipients of viraemic blood were ELISA positive and seven (41%) were PCR positive. Resolved HCV infection, as determined by ELISA pos, RIBA pos or indeterminate and PCR negativity, occurred in five of 12 (42%). In many instances there was more than one recipient per HCV infected donation. All of the reported children are clinically asymptomatic. However, the duration of HCV infection is relatively short and there is evidence of a degree of hepatitis in five of the seven children who are HCV RNA positive as judged by mildly elevated transaminase levels. The three who have undergone liver biopsy show mild hepatitis. The lower rates of persistence of HCV infection in this study may be due to the young age at exposure or to the source of infection which for all but one of the children was linked to one HCV genotype from female donors. Sharing of units of blood among multiple infants should be discouraged.

Hepatitis C virus infection in the mothers and infants cohort study

OBJECTIVES

To estimate the hepatitis C virus (HCV) vertical transmission rate, the effect of potential risk factors, and the pattern of HCV antibody response and viremia in HCV-infected infants.

STUDY DESIGN

The Mothers and Infants Cohort Study enrolled both human immunodeficiency virus (HIV)-seropositive and HIV-seronegative pregnant women at five obstetric clinics in New York City in a prospective cohort study between January 1986 and January 1991. HCV-infected mothers and their 122 offspring were followed-up for a minimum of 12 months for evidence of HCV infection as determined by persistent HCV antibodies or detection of HCV RNA by reverse transcription polymerase chain reaction. Comparisons among groups for categorical variables were performed using the Fisher's exact test.

RESULTS

Seven (6%; 95% confidence interval, 2%-11%) of the 122 infants were HCV-infected. There was a tendency for increased risk of transmission with maternal viral and obstetrical factors, such as coinfection with HIV (7% vs 4%), high HIV viral load (13% vs 6%), HCV viremia (8% vs 3%), vaginal delivery (6% vs 0%), and female gender of offspring (8% vs 3%), although none of the associations reached statistical significance. After loss of maternal antibody, HCV antibody seroconversion occurred at a mean age of 26 months in 3 HIV-coinfected infants compared with 7 months of age in 4 HCV-infected HIV-uninfected infants. Serial samples showed that HCV RNA persisted in 6 infants for at least 18 to 54 months.

CONCLUSIONS

Our study is in accordance with other studies that have shown low overall HCV vertical transmission risk and a trend toward higher risk with maternal risk factors such as HIV-coinfection or HCV viremia. A delay in infant HCV antibody response may be associated with HIV coinfection although larger studies are needed to confirm these findings.

Hepatitis C virus infection in pediatric patients

In contrast to our understanding of hepatitis C virus infection in adults, relatively little is known about the evolution and treatment of HCV infection in pediatric patients. Children at risk for HCV infection include recipients of multiple blood-product transfusions, organ transplantation and infants born to HCV-infected mothers. A proportion of HCV-infected pediatric patients do not have an identifiable risk factor. HCV infection is commonly detected in children previously presumed to have non-A, non-B hepatitis and cryptogenic liver disease. HCV infection usually leads to mild chronic liver disease in children but is also associated with chronic active hepatitis and cirrhosis. Interferon therapy is effective in a proportion of patients with chronic hepatitis C.

Use of polymerase chain reaction and antibody tests in the diagnosis of vertically transmitted hepatitis C virus infection

Data on patterns of polymerase chain reaction (PCR) and antibody test results in infants born to hepatitis C virus (HCV)-infected mothers were systematically reviewed to aid development of optimum testing schedules and diagnostic criteria for vertically exposed infants and to facilitate early identification of infected infants. Survival and cross-sectional analyses were used to estimate the timing of initial PCR positivity and subsequent PCR negativity in infected infants, and maternal antibody loss in uninfected infants was estimated as a weighted average of individual study findings. Of 74 eligible infants with strong evidence of HCV infection, an estimated 89% (90% confidence interval, 80-95%) were first PCR positive by 3 months of age, and less than 10% had subsequent PCR negativity attributable to intermittent viraemia or resolved infection in the first 18 months of life. The negative predictive value of PCR at 3 months of age was greater than 98% at an assumed rate of 5% vertical transmission, but as low as 88% at 25% transmission. The inclusion of 22 infants, each with a single PCR-positive result, increased the estimated frequency of resolved infections but made little difference to other estimates. A minority of PCR-positive infants had periods of antibody negativity by second- or third-generation assays, and among 297 uninfected infants, maternal antibody was not detected beyond 18 months. Thus, the majority of infected infants may be persistently PCR positive from 3 months of age, and the negative predictive value of PCR at 3 months is generally high. However, poor repeatability of PCR, inadequate infant follow-up, and inclusion of postnatally infected infants limits interpretation of the pooled data. Further studies using standardised PCR methodologies are needed.

[Rationale for a trial of prevention of perinatal transmission of hepatitis C via specific immunoglobulins]

Vertical transmission of the HCV infection is asymptomatic, occurring in 0-25% of infants born to viremic mothers in Europe. Nowadays, the only preventive measure in to advise against breastfeeding. Favourable conditions for a seroprophylaxis trial in neonates at risk are the low viral charge and the absence of former replication or integration. Several impediments to a randomized-controlled trial should be considered: Epidemiological: paucity of recruitment; low risk of transmission; possible antenatal transmission in cases of high maternal viremia; risk for intrafamilial transmission. Methodological: complex randomization of the study groups (genotyping, quantitative PCR, activity of mothers' diseases, modes/durations of delivery and feeding). Ethical: a direct individual benefit is not clearly established; should viremic mothers be allowed to breast feed their babies in the absence of prophylaxis? the risk of the emergence of mutants or quasi-species of the transmitted hepatitis C virus in neonates; the origin and selection of seropositive plasma donors.

Endotoxin and renal glutamine metabolism

The effect of endotoxin on renal glutamine metabolism and ammoniagenesis was investigated in vivo in the rat to gain further insight into the altered glutamine flow that characterizes critical illness. Studies were done 15 hours following a single dose of Escherichia coli lipopolysaccharide (10 mg/kg). Renal blood flow and arterial glutamine concentration were similar in control and study rats, but the kidney switched from an organ of slight glutamine uptake in controls (129 +/- 52 nmol/100 g of body weight per minute) to net release in the endotoxin-treated animals (-273 +/- 170 nmol/100 g of body weight per minute). Simultaneously, the specific activity of renal glutamine synthetase increased by almost 50% (374 +/- 40 nmol/mg of protein per hour in rats given endotoxin vs 253 +/- 12 nmol/mg of protein per hour in controls), while glutaminase was unchanged. Urinary ammonia excretion was reduced by 35% in the endotoxin-treated animals (47 +/- 6 mumol/12 h in endotoxin-treated animals vs 70 +/- 8 mumol/12 h in controls) despite a 10% fall in the arterial bicarbonate value. Endotoxin alters the net flux of glutamine across the kidney which appears to be partially regulated enzymatically. This may impair the kidneys' ability to maintain acid/base homeostasis.