Evaluation of the role of hepatitis C virus in biliary atresia

Detection of hepatotropic viruses has no impact on the prognosis after Kasai procedure

BACKGROUND/PURPOSE

A viral origin of biliary atresia (BA) is discussed, and several studies have demonstrated different viral strains in liver biopsies of patients undergoing Kasai portoenterostomy. We hypothesized that the presence of hepatotropic viruses in patients undergoing portoenterostomy contributes to the progression of the disease and negatively affect the outcome.

METHODS

Liver biopsies were prospectively taken from 70 patients undergoing portoenterostomy in our department from April 1996 to April 2004. Samples were screened by polymerase chain reaction for all common hepatic viruses. Primary outcome parameter was survival with the native liver. Secondary parameters were postoperative serum activity of liver enzymes and serum bilirubin levels at different time points. Patients underwent regular follow-up until October 2008.

RESULTS

Twenty-eight patients (40%) were positive for 1 or more hepatotropic viruses. Four patients were lost to follow-up. In the remaining 66 patients, there was no significant difference in survival with their native liver between virus-positive and virus-negative patients. After a mean follow-up of 7.7 years (range, 4.6-16.1 years), 15 (23%) of 66 patients still lived with their native liver. There was no difference in liver enzymes, C-reactive protein, or bilirubin at any time point between both groups.

CONCLUSION

A significant number of our patients tested positive for hepatotropic viruses in liver biopsies at the time of the Kasai procedure, but the presence of virus had no influence on the course of BA. This suggests that the ongoing inflammatory process of BA leading to liver cirrhosis in most Kasai-treated patients is not affected by hepatotropic viruses. Our data question the necessity to aggressively screen for and treat viral infections in patients with BA.

Biliary atresia

Biliary atresia (BA) is a cholangiodestructive disease affecting biliary tract, which ultimately leads to cirrhosis, liver failure and death if not treated. The incidence is higher in Asian countries than in Europe. Up to 10% of cases have other congenital anomalies, such as polysplenia, asplenia, situs inversus, absence of inferior vena cava and pre-duodenal portal vein, for which we have coined the term Biliary Atresia Splenic Malformation (BASM) syndrome. For these infants the aetiology lies within the first trimester of gestation. For others affected with BA, aetiology is more obscure and perinatal destruction of fully-formed ducts perhaps by the action of hepatotropic viruses has been suggested. Whatever the cause, the lumen of the extrahepatic duct is obliterated at a variable level and this forms the basis for the commonest classification (Types I, II, III). All patients with BA present with varying degree of conjugated jaundice, pale non-pigmented stools and dark urine. Key diagnostic tests include ultrasonography, biochemical liver function tests, viral serology, and (in our centre) a percutaneous liver biopsy. In some centres, duodenal intubation and measurement of intralumenal bile is the norm. Currently BA is being managed in two stages. The first stage involves the Kasai operation, which essentially excises all extrahepatic biliary remnants leaving a transected portal plate, followed by biliary reconstruction using a Roux loop onto that plate as a portoenterostomy. If bile flow is not restored by Kasai procedure or life-threatening complications of cirrhosis ensue then consideration should be given to liver transplantation as a second stage. The outcome following the Kasai operation can be assessed in two ways: clearance of jaundice to normal values and the proportion who survive with their native liver. Clearance of jaundice (<2 mg/dL or <34 µmol/L) after Kasai has been reported to be around 60%, whereas five years survival with native liver ranges from 40% to 65%.

Study of viral infections in infants with biliary atresia

Viral infections may have an important role in the pathogenesis of biliary atresia, and related clinical outcomes. In this research for determination of the possible role of HBV, HCV, HCMV, adenovirus, and BK virus infections in biliary atresia related clinical complications, the molecular and antigenic prevalence of these viral agents were studied. In this retrospective study, 34 formalin fixed paraffin embedded (FFPE) biopsy and autopsy liver tissue samples of neonates with biliary atresia were evaluated. The molecular prevalence of these viral infections was assayed by different PCR and RT-PCR methods. The antigenic prevalence of HBV, HCV, and HCMV infections was also studied in these liver tissue samples by immunohistochemistry (IHC) method. HBV, HCV, and adenovirus genomes were detected in 9%, 6%, and 6% of liver autopsy and biopsy tissues of infants with biliary atresia, respectively. HBV and HCV co-infection was confirmed in 6% of FFPE samples. The genome of other investigated viruses was not detected in FFPE liver tissues. Detection of viral infection in FFPE liver tissue samples of newborns with biliary atresia, suggests the need for complete studies for the determination of accurate role of these viral infections in pathogenesis of biliary atresia.

Incidence of hepatotropic viruses in biliary atresia

Biliary atresia (BA) is the most frequent indication for paediatric liver transplantation. We tested the hypothesis of a viral aetiology of this disease by screening liver samples of a large number of BA patients for the common human hepatotropic viruses. Moreover, we correlated our findings to the expression of Mx protein, which has been shown to be significantly up-regulated during viral infections. Seventy-four liver biopsies (taken during Kasai portoenterostomy) were tested by polymerase chain reaction (PCR) for DNA viruses (herpes simplex virus [HSV], Epstein-Barr virus [EBV], varicella zoster virus [VZV], cytomegalovirus [CMV], adenovirus, parvovirus B19 and polyoma BK) and RNA viruses (enteroviruses, rotavirus and reovirus 3). Mx protein expression was assessed by immunohistochemistry. Virus DNA/RNA was found in less than half of the biopsies (8/74 CMV, 1/74 adenovirus; 21/64 reovirus, 1/64 enterovirus). A limited number presented with double infection. Patients that had detectable viral RNA/DNA in their liver biopsies were significantly older than virus-free patients (P = 0.037). The majority (54/59) of the liver biopsies showed expression of Mx proteins in hepatocytes, bile ducts and epithelium. Our data suggest that the known hepatotropic viruses do not play a major role in the aetiology and progression of BA. Their incidence appears to be, rather, a secondary phenomenon. Nonetheless, the inflammatory response in the livers of BA patients mimics that observed during viral infections.

Biliary atresia: recent progress

Extrahepatic biliary atresia (EHBA), an inflammatory sclerosing cholangiopathy, is the leading indication for liver transplantation in children. The cause is still unknown, although possible infectious, genetic, and immunologic etiologies have received much recent focus. These theories are often dependent on each other for secondary or coexisting mechanisms. Concern for EHBA is raised by a cholestatic infant, but the differential diagnosis is large and the path to diagnosis remains varied. Current treatment is surgical with an overall survival rate of approximately 90%. The goals of this article are to review the important clinical aspects of EHBA and to highlight some of the more recent scientific and clinical developments contributing to our understanding of this condition.

Incidence of hepatotropic viruses in biliary atresia

Biliary atresia (BA) is the most frequent indication for paediatric liver transplantation. We tested the hypothesis of a viral aetiology of this disease by screening liver samples of a large number of BA patients for the common human hepatotropic viruses. Moreover, we correlated our findings to the expression of Mx protein, which has been shown to be significantly up-regulated during viral infections. Seventy-four liver biopsies (taken during Kasai portoenterostomy) were tested by polymerase chain reaction (PCR) for DNA viruses (herpes simplex virus [HSV], Epstein-Barr virus [EBV], varicella zoster virus [VZV], cytomegalovirus [CMV], adenovirus, parvovirus B19 and polyoma BK) and RNA viruses (enteroviruses, rotavirus and reovirus 3). Mx protein expression was assessed by immunohistochemistry. Virus DNA/RNA was found in less than half of the biopsies (8/74 CMV, 1/74 adenovirus; 21/64 reovirus, 1/64 enterovirus). A limited number presented with double infection. Patients that had detectable viral RNA/DNA in their liver biopsies were significantly older than virus-free patients (P = 0.037). The majority (54/59) of the liver biopsies showed expression of Mx proteins in hepatocytes, bile ducts and epithelium. Our data suggest that the known hepatotropic viruses do not play a major role in the aetiology and progression of BA. Their incidence appears to be, rather, a secondary phenomenon. Nonetheless, the inflammatory response in the livers of BA patients mimics that observed during viral infections.

Detection of Epstein Barr virus by chromogenic in situ hybridization in cases of extra-hepatic biliary atresia

Introduction

Extra-hepatic biliary atresia (EHBA) is an important cause of neonatal cholestasis. Several infectious agents have been proposed as etiologic factors such as Rotavirus and Reovirus. There is limited data on the role of Epstein Barr virus (EBV) infection in EHBA, so we decided to study the presence of EBV virus in a series of 16 proven EHBA cases by Chromogenic in situ hybridization (CISH) technique.

Methods

In the current study a total of 16 liver wedge biopsies of proven cases of EHBA were selected in a period of 4 years. CISH staining for EBV-encoded RNA (EBER) transcript was performed.

Results

The review of H&E-stained slides of liver biopsies revealed fibrosis and marked ductular proliferation. In CISH-stained slides, EBV trace was observed in hepatocytes in two cases and in biliary epithelium in one case of EHBA.

Discussion

Considering the association of hepatitis with the Epstein-Barr virus in later life, it is likely that EBV hepatitis and its complications occur in the neonatal/perinatal period. Since EHBA is a relatively rare disease, a similar study on wedge biopsies of this number of proven cases of EHBA has not been performed to date. Current observation proposes the need for a study of larger series and employing other methods for confirming the etiologic role of EBV in EHBA cases.

Biliary atresia

Biliary atresia (BA) is a rare disease characterised by a biliary obstruction of unknown origin that presents in the neonatal period. It is the most frequent surgical cause of cholestatic jaundice in this age group. BA occurs in approximately 1/18,000 live births in Western Europe. In the world, the reported incidence varies from 5/100,000 to 32/100,000 live births, and is highest in Asia and the Pacific region. Females are affected slightly more often than males. The common histopathological picture is one of inflammatory damage to the intra- and extrahepatic bile ducts with sclerosis and narrowing or even obliteration of the biliary tree. Untreated, this condition leads to cirrhosis and death within the first years of life. BA is not known to be a hereditary condition. No primary medical treatment is relevant for the management of BA. Once BA suspected, surgical intervention (Kasai portoenterostomy) should be performed as soon as possible as operations performed early in life is more likely to be successful. Liver transplantation may be needed later if the Kasai operation fails to restore the biliary flow or if cirrhotic complications occur. At present, approximately 90% of BA patients survive and the majority have normal quality of life.

Expression of the interferon-induced Mx proteins in biliary atresia

Biliary atresia (BA) is a rare disease of the newborn for which the Kasai procedure is curative only for a few of the patients. The dilemma is that all therapeutic attempts to cure the disease are symptomatic because the etiology is still unclear. One theory suggests a progressive inflammatory process, possibly induced by a viral infection. The aim of the present study was to investigate the activity of type I interferons (IFNs) in the livers of patients with BA. Mx proteins, which mediate an early innate immune response, are a very sensitive marker for type I IFN activity (eg, to viral infection). Liver biopsies were taken during the Kasai procedure from 13 newborns with BA who were serologically negative for hepatotropic viruses. Age-matched controls originated from 7 patients with neonatal cholestasis (eg, inspissated bile syndrome), 3 aborted fetuses, and a 10-year-old child. The immunostaining procedure (alkaline phosphatase anti-alkaline phosphatase) was performed with Mx-specific monoclonal antibody. Immunostaining for Mx proteins was positive in the hepatocytes of all newborns with BA, whereas the intrahepatic bile ducts were positive in all but one. In the control group, 8 of 11 liver samples were Mx-negative. This is the first study dealing with the detection of type I IFN activity in the liver of patients with BA. This observation supports the etiologic consideration of type I IFN-mediated immune response. Although positive findings of viruses in patients with BA are still inconsistent, the present study retraces the progressive inflammatory process in BA one more step toward its beginning.

Potential etiologies of biliary atresia

Biliary atresia is the most common cause of neonatal cholestasis and the leading indication for pediatric liver transplantation worldwide. The disease is caused by a progressive inflammatory and fibrosing obliteration of the extrahepatic bile ducts. Although the cause of this obstruction is largely unknown, patient-based studies have identified environmental and genetic factors that may interact and orchestrate disease pathogenesis. Chief among these factors are infectious and immunologic processes. While infectious agents have varied in different patient populations, studies of liver specimens at different phases of disease point to a pro-inflammatory commitment of lymphocytes at the time of diagnosis, and to their potential role in regulating bile duct obstruction. A review of these studies is the focus of this article.

[Biliary atresia: Retrospective clinical study]

OBJECTIVE

To gain further insight into the natural history of patients with biliary atresia.

PATIENTS AND METHODS

We performed a retrospective, cross-sectional, descriptive, case series study. All patients with biliary atresia attended at the Pediatric Gastrointestinal and Hepatology Unit of La Fe Children's Hospital in Valencia (Spain) from January 1990 to December 2000 were included.

RESULTS

Of 16 children followed-up, eight are currently stable, six have undergone liver transplantation and two died. The mean age at diagnosis was 47.5 days. The most frequent clinical manifestation was jaundice (87.5%) and the most common biochemical finding was raised gamma-glutamyltransferase (3-4 times its standard value), which appeared in 100 % of the patients. Abdominal ultrasonography was diagnostic in 85.7% of the patients. Nuclear scintiscan (DISIDA) showed a sensitivity of 100%. Portoenterostomy with intraoperative liver biopsy was performed in all patients. Patient age at surgery was a predictor of long-term outcome, with more favorable results in patients aged less than 65 days of life.

CONCLUSIONS

Biliary atresia should be suspected as soon as possible, since early surgical treatment is the only therapeutic measure that can improve outcome.

Biliary atresia

BA is a rare disease of unclear etiology; nevertheless, its impact in the field of pediatric hepatology is significant. It is the most common surgically correctable cause of neonatal cholestasis and is the most common pediatric disease referred for liver transplantation. Little progress has been made with regard to improving outcome or understanding its pathogenesis in the past decade. Fortunately, however, a national, government-sponsored collaborative endeavor has begun that will hopefully make a significant impact upon the progress of designing new treatments for BA and develop a better understanding of its pathogenesis.

Epidemiology of biliary atresia in France: a national study 1986-96

BACKGROUND/AIMS

The reported incidence of biliary atresia varies from 5 to 32/100000 live births. The existence of seasonality and/or clustering is controversial. Based on a large population analysis, we examined the incidence of biliary atresia in France, and the space-time distribution of cases.

METHODS

All patients with biliary atresia living in France and born in the years 1986-96 were recorded. Geographic distribution, seasonality, time clustering and space-time clustering were analysed. Statistical analysis used the Chi square test, the Spearman nonparametric correlation test, the Walter and Elwood test for seasonality of events and Knox analysis for time and space-time clustering.

RESULTS

We identified 461 patients: 421 born in metropolitan France (incidence 5.12 [4.63-5.61]/100000 live births), and 40 born in overseas territories. No significant regional variation in incidence was found in metropolitan France, while the incidence was higher in French Polynesia (incidence 29.4 [15.4-43.3]/100000 live births) (p<0.001). Seasonality, time-clustering and time-space clustering could not be demonstrated.

CONCLUSIONS

1) The incidence of BA was 5.7-fold higher in Polynesia than in metropolitan France. 2) Neither seasonal variation in incidence nor clustering was identified.

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.

Epidemiology of biliary atresia: a population-based study

OBJECTIVE

Biliary atresia is the leading cause of extrahepatic obstructive jaundice in the newborn and is the single most frequent indication for liver transplantation in children. The cause of biliary atresia is unknown, although several mechanisms have been postulated to explain the inflammatory process that obliterates the bile ducts. Most interest has been directed toward viral infections. Information about the epidemiologic characteristics of biliary atresia in well-defined populations is lacking but is essential for developing and addressing hypotheses of causation for the disease.

METHODS

Infants with biliary atresia were identified in metropolitan Atlanta from 1968 through 1993 by a population-based birth defects surveillance system that ascertains infants with serious birth defects in the first year of life using active case ascertainment. Birth prevalence rates were analyzed for spatial and temporal clustering and effects attributable to county of residence, sex, race, maternal age, parity, and birth weight. Logistic regression was used to study the independent effects of the risk factors and to look for interactions.

RESULTS

Fifty-seven infants with biliary atresia were identified, for a rate of 0.73 per 10,000 live births. There was significant seasonal clustering of the disease, with rates three times higher from December through March compared with rates from April through July. Rates were significantly higher among nonwhite infants compared with white infants (0.96 vs 0.44 per 10,000 live births) and infants born at term with low birth weights (<2500 g) compared with infants born at term with normal birth weights (> or = 2500 g) (2.62 vs 0.75 per 10,000 live births).

CONCLUSIONS

Our study is the first in the United States to describe the epidemiologic characteristics of biliary atresia using a population-based approach. The demonstration of significant seasonal clustering provides support for theories that biliary atresia may be caused by environmental exposure (consistent with a viral cause) during the perinatal period.

Is early response to portoenterostomy predictive of long-term outcome for patients with biliary atresia?

PURPOSE

Therapy for biliary atresia (BA) typically involves portoenterostomy (PE). In light of the development of liver transplantation (LT) as an option for therapy in infancy, the authors reviewed their experience to determine factors that might predict the requirement for LT.

METHODS

Cases of BA diagnosed between September 1980 and September 1994 were reviewed. Responses to PE were rated as poor (PR; death or LT by 3 years), temporary (TR; LT > 3 years), or good (GR; anicteric).

RESULTS

Twenty-nine patients were identified; 24% were native indian or Inuit. Twenty-three had PE; 11 responded. Seven (32%) became anicteric and continue to do well (GR). Four (18%) required LT after age 3 (TR). Twelve patients had PR; 3 underwent LT (average age, 1.3 years), 4 are listed for LTX, and 5 died by age 2.8 years. (Six patients did not have PE; 2 died in infancy and 4 had LT.) All transplant recipients are well. Factors associated with PR were older age at time of surgery (67 +/- 7 days v 51 +/- 4 days in the GR group), nadir of AST (273 +/- 84 U/Lv 70 +/- 26 U/L in the GR group), and number of post-PE complications (3.6 v per patient v 1 per patient in the GR group). TR was differentiated from GR by bilirubin nadir (46 +/- 10 mumol/Lv 14 +/- 3 mumol/L, respectively) and rate of bilirubin decline (2.6 +/- 1.5 mumol/L/d v 10.8 +/- 3.0 mumol/L/d, respectively). (P < .05 for all comparisons.)

CONCLUSION

Outcomes are comparable to those of North American series, but the incidence is lower overall and is higher among natives. Factors that correlate with outcome include age at time of surgery, post-PE complications, postoperative decline and rate of decline of bilirubin and AST. The latter had not been reported previously and may prove useful in planning therapy for partial responders after PE.