Early cytomegalovirus infection and the long-term outcome of biliary atresia

Incidence and antiviral treatment of cytomegalovirus infection in infants with biliary atresia

PURPOSE

Patients with biliary atresia (BA) and cytomegalovirus (CMV) infection may have poorer outcomes after Kasai portoenterostomy (KPE) than uninfected patients, suggesting a rationale for antiviral treatment (AVT). We aimed to describe the incidence of CMV infection and of AVT in BA patients, and to detect any differences between infected and uninfected patients to conclude if AVT is of use.

METHODS

Data on BA patients who underwent KPE 2004-2020 were retrospectively collected, and the outcome was analyzed with regard to CMV status.

RESULTS

Fifteen out of forty-six (33%) BA patients had signs of ongoing CMV infection. They did not differ significantly from the CMV-negative patients regarding rate of prematurity, birth weight, or biochemical markers but were slightly older at KPE. All patients received steroids postoperatively and all patients with ongoing CMV infection received AVT with very good effect on viremia and without major side effects. The AVT consisted of oral valganciclovir (10-40 (- 58) mg/kg/d) or intravenous ganciclovir (5.3-11 mg/kg/d).

CONCLUSION

Ongoing CMV infection is common in this group of patients. The viremia can effectively be treated with AVT without any major side effects. Larger, randomized studies are needed to clarify the possible effect on clinical outcome.

A Comparative Study Between Cytomegalovirus Immunoglobulin M-Positive and CMV Immunoglobulin M-Negative Biliary Atresia in Infants Attending a Tertiary Care Hospital in Bangladesh

PURPOSE

Perinatal cytomegalovirus (CMV) infection can lead to biliary atresia (BA) in different entities. This study aimed to compare the clinical, hematological, biochemical, and histological features of infants with BA based on their CMV immunoglobulin M (IgM) status at presentation.

METHODS

This cross-sectional descriptive study was carried out between January 2019 and June 2020 at the Department of Pediatric Gastroenterology and Nutrition at the Bangabandhu Sheikh Mujib Medical University (BSMMU) in Dhaka. Forty-three patients with BA were selected purposively and categorized into either the CMV IgM-positive or CMV IgM-negative BA group. Categorical variables were compared using Fisher's exact test and chi-square tests, while the Student's t-test and Mann-Whitney U-test were used to compare continuous variables. For all statistical tests, a p-value <0.05 was considered statistically significant.

RESULTS

Thirty-three (76.7%) of the cases were between 2 and 3 months of age on admission. The clinical, hematological, and biochemical parameters did not differ significantly between the CMV IgM-positive and CMV IgM-negative BA groups. Most (50.0%) of the CMV IgM-positive cases had fibrosis stage F2, while 43.5% of the CMV IgM-negative cases had fibrosis stage F3, with no significant difference between the groups (p=0.391).

CONCLUSION

Our data shows no significant distinction between CMV IgM-positive and CMV IgM-negative BA, suggesting that CMV does not contribute to BA pathogenesis.

Biliary Atresia Animal Models: Is the Needle in a Haystack?

Biliary atresia (BA) is a progressive fibro-obliterative process with a variable degree of inflammation involving the hepatobiliary system. Its consequences are incalculable for the patients, the affected families, relatives, and the healthcare system. Scientific communities have identified a rate of about 1 case per 10,000-20,000 live births, but the percentage may be higher, considering the late diagnoses. The etiology is heterogeneous. BA, which is considered in half of the causes leading to orthotopic liver transplantation, occurs in primates and non-primates. To consolidate any model, (1) more transport and cell membrane studies are needed to identify the exact mechanism of noxa-related hepatotoxicity; (2) an online platform may be key to share data from pilot projects and new techniques; and (3) the introduction of differentially expressed genes may be useful in investigating the liver metabolism to target the most intricate bilio-toxic effects of pharmaceutical drugs and toxins. As a challenge, such methodologies are still limited to very few centers, making the identification of highly functional animal models like finding a "needle in a haystack". This review compiles models from the haystack and hopes that a combinatorial search will eventually be the root for a successful pathway.

Effects of cytomegalovirus infection on the differential diagnosis between biliary atresia and intrahepatic cholestasis in a Chinese large cohort study

INTRODUCTION AND OBJECTIVES

Differentiating biliary atresia from other causes of neonatal cholestasis is challenging, particularly when cytomegalovirus (CMV) and biliary atresia occur simultaneously. We aimed to elucidate whether CMV infection would affect the differential diagnosis of biliary atresia and intrahepatic cholestasis.

PATIENTS AND METHODS

This retrospective study was conducted among patients with neonatal cholestasis admitted to three tertiary hospitals between January 2010 and August 2019. The clinical characteristics, laboratory, and imaging findings were recorded. On the basis of the CMV serology results, the infants were classified into CMV-IgM (+) and CMV-IgM (-) groups. The clinical differences and diagnostic performances of routine predictors between biliary atresia and intrahepatic cholestasis were analyzed in each group. Finally, we compared the diagnostic performances of various tests in the two groups.

RESULTS

A total of 705 patients with neonatal cholestasis were enrolled: 215 (30.5%) patients were positive for CMV-IgM, among whom 97 had biliary atresia and 118 had CMV hepatitis; 490 infants were CMV-IgM (-), among whom 240 had biliary atresia and 250 had intrahepatic cholestasis. The diagnostic performances of stool color, direct bilirubin level, γ-glutamyl transpeptidase level, abnormal gallbladder, triangular cord sign, and hepatobiliary scintigraphy between CMV hepatitis and CMV-IgM (+) biliary atresia were similar to those between CMV-IgM (-) biliary atresia and CMV-IgM (-) intrahepatic cholestasis groups.

CONCLUSIONS

Our large-scale study showed a high prevalence of CMV infection in patients with neonatal cholestasis in China. The presence of CMV infection did not affect the routine predictors to discriminate biliary atresia and intrahepatic cholestasis.

Detection of Cytomegalovirus Infection in Infants with Biliary Atresia: A Meta-analysis

Objectives  Biliary atresia (BA) is the most common indication of liver transplantation in children. Several reports attributed BA to both prenatal and perinatal etiologies, including a viral infection-induced autoimmune response that targets the bile ducts. Cytomegalovirus (CMV) remains the most common virus being linked to BA. This meta-analysis aimed to estimate to what extent CMV infection is detected in patients with BA.

Methods  This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The databases of MEDLINE, Embase, Scopus, WHO-Virtual Health Library (VHL), ScienceDirect, and Google Scholar were used for the systematic search. The risk of bias was assessed using the Newcastle–Ottawa scale. Random effects model was used to estimate the pooled prevalence estimate with the corresponding 95% confidence interval (CI) using Comprehensive Meta-Analysis Software version 3.3.

Results  A total of 19 studies that fulfilled the eligibility criteria were included in the meta-analysis. The total number of infants with BA was 630 patients, and the pooled overall prevalence of CMV infection among them was 25.4% (95% CI: 15.9%–38.0%). There was high heterogeneity among studies (I ²  = 85.1%, p  < .001), and subgroup analyses showed significant regional differences (X ²  = 48.9, p <.001). Data on the prognosis of CMV-associated BA were scarce and obtainable from few studies that suggested an association between detection of CMV infection and poor prognosis of BA.

Conclusions  The limited available data demonstrates that the rate of detection of CMV infection is high in infants with BA. There is still a need for large studies with appropriate controls for obtaining more reliable results about the various aspects of the association between CMV infection and BA.

Prognosis of Biliary Atresia Associated With Cytomegalovirus: A Meta-Analysis

Objective: The etiology of biliary atresia is unclear, but viral infection has been implicated. The aim of the current meta-analysis was to investigate relationships between cytomegalovirus (CMV) and the prognosis of biliary atresia. Methods: PubMed, Embase, the Cochrane Library, the China National Knowledge Infrastructure database, and Wanfang Data electronic databases were searched for eligible studies. Each relevant text was thoroughly reviewed and examined, including related papers in their reference lists. Results: A total of nine studies including 784 patients were included in the analysis. Biliary atresia patients with CMV exhibited significantly lower jaundice clearance (odds ratio: 0.46, p < 0.0001; I ² = 15%, p = 0.31). There were no significant differences in the rates of cholangitis or native liver survival. CMV-pp65-positive biliary atresia patients had a significantly lower rate of jaundice clearance (odds ratio: 5.87, p = 0.003; I ² = 0%, p = 0.71) and a significantly higher rate of cholangitis (odds ratio: 0.21, p = 0.01; I ² = 0%, p = 0.43) than CMV antibody-positive biliary atresia patients. Conclusion: Biliary atresia patients who were also infected with CMV had a poorer prognosis, particularly with respect to jaundice clearance. CMV status may influence the prognosis of biliary atresia. Clinicians should be able to routinely identify the subset of biliary atresia patients who are also CMV-positive, in order to improve native liver survival.

Biological and Histological Assessment of the Hepatoportoenterostomy Role in Biliary Atresia as a Stand-Alone Procedure or as a Bridge toward Liver Transplantation

Background and objectives: In patients with biliary atresia (BA), hepatoportoenterostomy (HPE) is still a valuable therapeutic tool for prolonged survival or a safer transition to liver transplantation. The main focus today is towards efficient screening programs, a faster diagnostic, and prompt treatment. However, the limited information on BA pathophysiology makes valuable any experience in disease management. This study aimed to analyze the evolution and survival of patients with BA referred for HPE (Kasai operation) in our department. Materials and Methods: A retrospective analysis was performed on fourteen patients with BA, diagnosed in the pediatric department and further referred for HPE in our surgical department between 2010 and 2016. After HPE, the need for transplantation was assessed according to patients cytomegalovirus (CMV) status, and histological and biochemical analysis. Follow-up results at 1–4 years and long term survival were assessed. Results: Mean age at surgery was 70 days. Surgery in patients younger than 60 days was correlated with survival. Jaundice’s clearance rate at three months was 36%. Total and direct bilirubin values had a significant variation between patients with liver transplants and native liver (p = 0.02). CMV was positive in eight patients, half with transplant need and half with native liver survival. Smooth muscle actin (SMA) positivity was proof of advanced fibrosis. The overall survival rate was 79%, with 75% for native liver patients and an 83% survival rate for those with liver transplantation. Transplantation was performed in six patients (43%), with a mean of 10 months between HPE and transplantation. Transplanted patients had better survival. Complications were diagnosed in 63% of patients. The mean follow-up period was six years. Conclusions: HPE, even performed in advanced cirrhosis, allows a significant survival, and ensures an essential time gain for patients requiring liver transplantation. A younger age at surgery is correlated with a better outcome, despite early CMV infection.

Using next-generation sequencing of microRNAs to identify host and/or pathogen nucleic acid signatures in samples from children with biliary atresia - a pilot study

Biliary atresia (BA) is a progressive disease affecting infants resulting in inflammatory obliteration and fibrosis of the extra- and intra-hepatic biliary tree. BA may be grouped into type 1 isolated; type 2 syndromic, where other congenital malformations may be present; type 3 cystic BA, where there is cyst formation within an otherwise obliterated biliary tree; and cytomegalovirus-associated BA. The cause of BA is unclear, with immune dysregulation, inflammation and infection, particularly with cytomegalovirus (CMV), all implicated. In this study a total of 50/67 samples were tested for CMV DNA using quantitative real-time PCR. Ten liver tissue and 8 bile samples from 10 patients representing the range of BA types were also analysed by next-generation sequencing. CMV DNA was found in 8/50 (16 %) patients and a total of 265 differentially expressed microRNAs were identified. No statistically significant differences between the various types of BA were found. However, differences were identified in the expression patterns of 110 microRNAs in bile and liver tissue samples (P<0.05). A small number of bacterial and viral sequences were found, although their relevance to BA remains to be determined. No direct evidence of viral causes of BA were found, although clear evidence of microRNAs associated with hepatocyte and cholangiocyte differentiation together with fibrosis and inflammation were identified. These include miR-30 and the miR-23 cluster (liver and bile duct development) and miR-29, miR-483, miR-181, miR-199 and miR-200 (inflammation and fibrosis).

Growth of children with biliary atresia living with native livers: impact of corticoid therapy after portoenterostomy

We addressed growth of biliary atresia (BA) patients living with native livers between ages 0-6 and effects of post-surgical corticosteroid treatment on growth. Growth charts of 28 BA patients born in Finland between 1987 and 2017 were retrospectively evaluated. Dosage and length of corticosteroid treatment and hydrocortisone substitution were reviewed. At birth, BA patients were shorter (median height - 0.6 (interquartile range (IQR) - 1.3 to - 0.1) SDS, n = 28, P < 0.001) than general population. Height remained stable during early childhood (median height - 0.6 (IQR - 1.4 to 0.1) SDS for girls and - 0.4 (IQR - 1.6 to 0.2) SDS for boys at 6 years of age). Patients were of normal height adjusted weight at 6 years with a median age and sex-adjusted body mass index (ISO-BMI) of 20.9 (IQR 19.3 to 25.0) for girls and 22.1 (IQR 20.7 to 25.6) for boys. Higher (≥ 50 mg/kg) cumulative post-portoenterostomy prednisolone dosage resulted in 0.18 SDS lower height per treatment week (β - 0.18, SE 0.04, P < 0.001) compared to lower dosage (< 50 mg/kg).Conclusion: BA patients grow normally during early childhood. As high postoperative corticosteroid dosage has a short-term negative effect on height, very high dosages should be avoided. What Is Known: • Growth of biliary atresia patients has mostly been shown to be within normal limits • Corticosteroids may decrease growth rate What Is New: • Biliary atresia patients surviving with their native livers are shorter than general population and their mid-parental target height at birth • A high (> 50 mg/kg) cumulative prednisolone dosage has a negative transitory impact on height gain after portoenterostomy.

Evidence for Viral Induction of Biliary Atresia: A Review

Biliary atresia (BA) is a childhood disease which manifests with abnormal narrowing, blockage or complete absence of bile ducts within the liver. Many possible etiologies have been reported for the development of BA, including congenital, perinatal and acquired conditions. Since the 1970's, there has been increasing evidence linking BA development to viral perinatal infections. The viral vectors most commonly implicated include members of the herpesviridae family (cytomegalovirus and Epstein-Barr virus) as well as those of the reoviridae family (reovirus and rotavirus). While extensive work has been done on a murine model of disease, the current review focuses primarily on evidence from human studies of viral vectors in children afflicted with BA.

Adjuvant therapy in biliary atresia: hopelessly optimistic or potential for change?

Given that the aetiology of biliary atresia (BA) is complex and that there is a multiplicity of possible pathogenic mechanisms then it is perhaps not surprising that the evidence for effect of a number of different agents is contradictory. Post-operative cholangitis for instance is common, bacterial in origin and various antibiotic regimens have been tested (although none in a randomized trial) but continuation beyond the early post-operative period does not appear to offer any greater protection. There is an inflammatory reaction in about 25-35% of cases of BA illustrated by abnormal expression of class II antigen and upregulation of ICAM, VCAM and E-selectin with an infiltrate of immune-activated T cells (predominantly CD4 + Th1 and Th17) and NK cells and a systemic surge in inflammatory cytokines (e.g. TNF-α, IL-2, IL-12). This has potential as a therapeutic target and is the main hypothesis behind the rationale use of steroids. The first report of steroids was published in 1985 by Karrer and Lilly as "blast" therapy to treat recalcitrant cholangitis, followed by a multiplicity of small-scale uncontrolled studies suggesting benefit. To date there has been one randomized placebo-controlled study with a low-dose (prednisolone 2 mg/kg/day) regimen (2007); one with a high-dose (IV prednisolone 4 mg/kg/day regimen) (2014); two prospective high-dose open-label studies (2013); a prospective comparison of low- and high-dose regimen and a large (380 infants) retrospective comparison. The most recent meta-analysis (2016) identified a significant difference in clearance of jaundice at 6 months (OR 1.59, 95% CI 1.03-2.45, P = 0.04), in patients treated with high-dose steroids, particularly if < 70 days at surgery. Ursodeoxycholic acid (UDCA) may increase choleresis or change the ratio of endogenous bile acids to a less hydrophobic and, therefore, less toxic millieu. UDCA may protect cholangiocyte membranes against damage and perhaps reduce the tendency to fibrogenesis. Biochemical benefit has been shown in a single crossover trial in older BA children who had cleared their jaundice. Other potential adjuvant therapies include immunoglobulin therapy, anti-viral agents and Chinese herbs although real evidence of benefit is lacking.

Surgical outcome and etiologic heterogeneity of infants with biliary atresia who received Kasai operation less than 60 days after birth: A retrospective study

This study aimed to analyze the impact of etiologic heterogeneity and operation age on prognosis of infants with biliary atresia (BA) who received Kasai operation prior to 60 days of age.From 2004 to 2010, 158 infants received Kasai operation before turning 60 days old. According to Davenport 2012 classifications, 4 groups of BA were defined: cystic BA, syndrome BA, and associated malformation, cytomegalovirus (CMV)-associated BA, and isolated BA. Native (autologous) liver survival rates and incidence of cholangitis 2 years after operation, as well as jaundice clearance rates 3 months after operation, were recorded.Although infants who received the operation between 51 and 60 days of age had a better jaundice clearance 3 months after operation and lower incidence of cholangitis as compared with those under 40 or between 41 and 50 days of age, there was no significant difference in survival rates. Among types of BA, infants with cystic BA had the best prognosis. In the syndrome BA and associated malformations group, as well as CMV-associated group, infants who received the operation early (<40 days of age) had a worse outcome as compared with those who received the operation between 41 and 50 days or 51 and 60 days of age.Both clinical etiologic heterogeneity and operation age may influence BA prognosis.

CD13 Autoantibodies Are Elevated in Sera From Mothers of Infants With Neonatal Cholestasis of Different Causes

OBJECTIVES

Human cytomegalovirus (HCMV) infection induces production of CD13-specific autoantibodies, which may promote inflammation and tissue damage. HCMV infection has been suggested as a cause of biliary atresia (BA), but little is known of its role in other forms of neonatal cholestasis. We studied serum levels of CD13-specific autoantibodies in mothers of infants with neonatal cholestasis of different causes, including BA, and in mothers of healthy, term infants without cholestasis, as well as in healthy blood donors.

METHODS

Using fluorescence-activated cell sorting, we measured CD13-specific autoantibody levels in serum from the above-mentioned groups. In addition, the effect of serum from mothers of infants with neonatal cholestasis was tested on the differentiation of monocytes into macrophages.

RESULTS

CD13-specific autoantibodies were found in mothers of infants with neonatal cholestasis, but not in mothers of infants without cholestasis and healthy blood donors, and were associated with HCMV seropositivity. Sera from mothers of infants with all forms of neonatal cholestasis inhibited differentiation of monocytes into macrophages, but this was not dependent on CD13-specific autoantibodies.

CONCLUSIONS

The significantly higher frequency of CD13-specific autoantibodies in mothers of infants with neonatal cholestasis of all forms compared with mothers of healthy infants without cholestasis suggests an association, but does not prove that they are pathogenic. The presence of CD13-specific autoantibodies does not correlate with HCMV IgG serostatus, suggesting a more complicated mechanism that possibly reflects active HCMV infection in these individuals. Further studies are needed to elucidate whether these autoantibodies contribute to the development of cholestasis or represent an epiphenomenon.

Cytomegalovirus-associated biliary atresia: An aetiological and prognostic subgroup

BACKGROUND AND AIMS

Perinatal cytomegalovirus (CMV) infection is a possible cause or trigger of biliary atresia though clinical evidence is scant. We hypothesised that CMV IgM+ve biliary atresia is a separate clinical entity compared to CMV IgM-ve biliary atresia.

METHODS

Prospective single-centre study. 210 infants with histologically confirmed biliary atresia were treated in our institution (Jan. 2004 to Dec. 2011); of these 20 (9.5%) were CMV IgM+ve at presentation. We compared these with 111 infants who were CMV IgM-ve (controls) for clinical features, biochemistry at presentation and outcome following Kasai portoenterostomy (KPE). A blinded comparison of age-matched liver histology was also performed. Data are quoted as median (interquartile range). A P value ≤ 0.05 was regarded as significant.

RESULTS

Infants with CMV IgM+ve biliary atresia were older at Kasai portoenterostomy (or laparotomy) [70 (60-80) days vs. 56 (44-75)days; P = 0.003] and were more jaundiced [175 (147-224) vs. 140 (121-181) μmol/L; P = 0.002+ with higher AST*287 (157-403) vs. 180 (133-254) IU/L; P = 0.005] and aspartate aminotransferase-to-platelet ratio index [1.1 (0.79-3.0) vs. 0.63 (0.43-0.95)] levels. Liver histology: CMV IgM+ve biliary atresia was characterised by a greater degree of inflammation (P < 0.0001) and fibrosis (P = 0.02), whereas CMV IgM-ve isolated biliary atresia had a higher degree of lobular cholestasis (P = 0.001). This effect was independent of the effects of age at KPE.

OUTCOME

CMV IgM+ve biliary atresia had a poorer outcome with a reduced clearance of jaundice (15% vs. 52.2%; P = 0.002), native liver survival (P < 0.0001) and increased mortality (P = 0.002).

CONCLUSIONS

CMV IgM+ve biliary atresia is a distinct clinical and pathological entity with a diminished response to Kasai portoenterostomy.

Th-17 cells infiltrate the liver in human biliary atresia and are related to surgical outcome

BACKGROUND

Biliary atresia (BA), a cholangiopathy of unknown etiology is associated with intrahepatic mononuclear cell infiltrate. An abnormal reaction to viral exposure has been hypothesized in some cases. We aimed to investigate the nature of the CD4+ hepatic infiltrate in defined clinical variants of BA by quantification of inflammatory cell components.

METHODS

Liver biopsies of infants obtained at Kasai portoenterostomy (KPE) were stained immunohistochemically using monoclonal antibodies to Tbet, GATA-3, FOXP3 and interleukin (IL) 17, identifying Th-1, Th-2, Tregs and Th-17 cells respectively. T cells were counted with the aid of a graticule. Data are reported as median (range) of cells per high-power-field (×400) and compared using nonparametric statistical tests with P≤0.05 regarded as significant.

RESULTS

Liver biopsies from BA (n=37) and age-matched cholestatic controls (e.g. alpha-1-anti trypsin deficiency, Alagilles syndrome, n=12) were investigated. BA infants were divided into three groups: cytomegalovirus IgM +ve (CMV; n=9); BA splenic malformation (BASM; n=9) and isolated BA (IBA; n=19). All T-cell subsets were present in the portal tracts, with an overrepresentation of Th-1 (P<0.001) and Th-17 (P<0.03), but not Th-2 (P=0.94) or Tregs (P=0.15), compared to controls. Th-1 cells predominated in the CMV group; (18 [7-37] vs. 3 [0-14] [BASM] and vs. 5 [3-23] [IBA]; P<0.01 both), while no subgroup differences were seen for Th-17 cells. The degree of Th-1 cell infiltrate inversely correlated with platelet count (rS=-0.49; P<0.01). Th-17 cells were fewer (6 [2-11] vs. 11 [8-20]; P=0.02) in infants who cleared their jaundice (n=15, <20μmol/L) although this did not translate to improved native liver survival (P=0.17).

CONCLUSIONS

Th-17 cells infiltrate the liver in BA and are associated with a worse surgical outcome; a Th-1 profile predominates in CMV-associated BA.

Pathogenesis of biliary atresia: defining biology to understand clinical phenotypes

Biliary atresia is a severe cholangiopathy of early infancy that destroys extrahepatic bile ducts and disrupts bile flow. With a poorly defined disease pathogenesis, treatment consists of the surgical removal of duct remnants followed by hepatoportoenterostomy. Although this approach can improve the short-term outcome, the liver disease progresses to end-stage cirrhosis in most children. Further improvement in outcome will require a greater understanding of the mechanisms of biliary injury and fibrosis. Here, we review progress in the field, which has been fuelled by collaborative studies in larger patient cohorts and the development of cell culture and animal model systems to directly test hypotheses. Advances include the identification of phenotypic subgroups and stages of disease based on clinical, pathological and molecular features. Stronger evidence exists for viruses, toxins and gene sequence variations in the aetiology of biliary atresia, triggering a proinflammatory response that injures the duct epithelium and produces a rapidly progressive cholangiopathy. The immune response also activates the expression of type 2 cytokines that promote epithelial cell proliferation and extracellular matrix production by nonparenchymal cells. These advances provide insight into phenotype variability and might be relevant to the design of personalized trials to block progression of liver disease.

Clues to the etiology of bile duct injury in biliary atresia

Biliary atresia (BA) is an infantile obstructive cholangiopathy of unknown etiology with suboptimal therapy, which is responsible for 40 to 50% of all pediatric liver transplants. Although the etiology of bile duct injury in BA in unknown, it is postulated that a pre- or perinatal viral infection initiates cholangiocyte apoptosis and release of antigens that trigger a Th1 immune response that leads to further bile duct injury, inflammation, and obstructive fibrosis. Humoral immunity and activation of the innate immune system may also play key roles in this process. Moreover, recent investigations from the murine BA model and human data suggest that regulatory T cells and genetic susceptibility factors may orchestrate autoimmune mechanisms. What controls the coordination of these events, why the disease only occurs in the first few months of life, and why a minority of infants with perinatal viral infections develop BA are remaining questions to be answered.

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: cellular dynamics and immune dysregulation

The cause of biliary atresia is unknown; in the past few decades, the majority of investigations related to its pathogenesis have centered on viral infections and immunity. The acquired or perinatal form of biliary atresia entails a progressive inflammatory injury of bile ducts, leading to fibrosis and obliteration of both the extrahepatic and intrahepatic bile ducts. Theories of pathogenesis include viral infection, chronic inflammatory or autoimmune-mediated bile duct injury, and abnormalities in bile duct development. This review will focus solely on human studies pertaining to a potential viral trigger of bile duct injury at diagnosis and provide insight into the interplay of the innate and adaptive immune responses in the pathogenesis of disease.

Cholangiocyte N-Ras protein mediates lipopolysaccharide-induced interleukin 6 secretion and proliferation

Cholangiocytes, the epithelial cells lining the bile ducts in the liver, are periodically exposed to potentially injurious microbes and/or microbial products. As a result, cholangiocytes actively participate in microbe-associated, hepatic proinflammatory responses. We previously showed that infection of cultured human cholangiocytes with the protozoan parasite, Cryptosporidium parvum, or treatment with gram-negative bacteria-derived LPS, activates NFκB in a myeloid differentiation 88 (MyD88)-dependent manner. Here, we describe a novel signaling pathway initiated by Toll-like receptors (TLRs) involving the small GTPase, Ras, that mediates cholangiocyte proinflammatory cytokine production and induction of cholangiocyte proliferation. Using cultured human cholangiocytes and a Ras activation assay, we found that agonists of plasma membrane TLRs (TLR 1, 2, 4, 5, and 6) rapidly (<10 min) activated N-Ras, but not other p21 Ras isoforms, resulting in the rapid (<15 min) phosphorylation of the downstream Ras effector, ERK1/2. RNA interference-induced depletion of TRAF6, a downstream effector of MyD88 and known activator of MAPK signaling, had no effect on N-Ras activation. Following N-Ras activation the proinflammatory cytokine, IL6, is rapidly secreted. Using a luciferase reporter, we demonstrated that LPS treatment induced IL6 promoter-driven luciferase which was suppressed using MEK/ERK pharmacologic inhibitors (PD98059 or U0126) and RNAi-induced depletion of N-Ras. Finally, we showed that LPS increased cholangiocyte proliferation (1.5-fold), which was inhibited by depletion of N-Ras; TLR agonist-induced proliferation was also inhibited following pretreatment with an IL6 receptor-blocking antibody. Together, our results support a novel signaling axis involving microbial activation of N-Ras likely involved in the cholangiocyte pathogen-induced proinflammatory response.

Pseudo gallbladder sign in biliary atresia--an imaging pitfall

BACKGROUND

Ultrasound (US) is used to identify causes of neonatal cholestasis. We describe a potential sonographic pitfall, the "pseudo gallbladder," in biliary atresia (BA).

OBJECTIVE

To describe the Pseudo Gallbladder sign (PsGB sign).

MATERIALS AND METHODS

Sonograms/clinical records of 20 confirmed BA infants and 20 non-BA cases were reviewed retrospectively. For the BA group, preoperative sonography and surgical and pathological findings were examined. For the non-BA group, sonographic features and pathological findings were examined. The PsGB sign is defined as a fluid-filled structure, located in the expected region of the gallbladder, measuring ≤ 15 mm in length but without a well-defined or normal-appearing gallbladder wall.

RESULTS

A recognizable gallbladder and normal gallbladder wall were present in all non-BA infants. However, none of the BA infants had a sonographically normal gallbladder. Seventy-three percent of BA patients had a PsGB, and in 27% no gallbladder or gallbladder-like structure was detected.

CONCLUSION

A gallbladder-like structure in BA is common and can be misinterpreted as a normal gallbladder, delaying diagnosis and therapy. Recognition of this imaging pitfall, described here as the pseudo gallbladder sign, will help avoid this error.