T-Bet Deficiency Attenuates Bile Duct Injury in Experimental Biliary Atresia

Biliary atresia (BA) is an obstructive neonatal cholangiopathy leading to liver cirrhosis and end stage liver disease. A Kasai portoenterostomy may restore biliary drainage, but most patients ultimately require liver transplantation for survival. At diagnosis, immune cells within the liver of patients with BA demonstrate a T-helper 1 (Th1) inflammatory profile similar to rhesus rotavirus (RRV)-infected mice livers developing BA. The transcription factor Tbx21 (T-bet) is essential for induction of a Th1 immune response in both the adaptive and innate immune system. Here we used animals with targeted deletion of the T-bet gene to determine its role in the progression of BA. Infection of newborn T-bet knockout (KO) pups with RRV resulted in a decreased Th1 inflammatory chemokine/cytokine profile when compared to infected wild-type mice. Analysis of the mononuclear cells profile from T-bet KO mice revealed both a significant decrease in the total number of CD3, CD4, and CD8 T cells and their effector molecules granzyme A, perforin, and FasL. Even though the percentage of T-bet KO mice displaying symptoms of an obstructive cholangiopathy and overall mortality rate was not different compared to wild-type mice, the extrahepatic bile ducts of T-bet KO mice remained patent.

A Rotavirus-Induced Mouse Model to Study Biliary Atresia and Neonatal Cholestasis

Biliary atresia is a devastating neonatal cholangiopathy that affects both extra- and intrahepatic bile ducts progressing to fibrosis and end-stage liver disease by 2 years of age. Despite re-establishment of biliary drainage following a Kasai portoenterostomy (surgical procedure), many infants develop fibrosis requiring liver transplant. In the murine model of biliary atresia, rhesus rotavirus infection of newborn pups results in a cholangiopathy paralleling human biliary atresia and is used to study mechanistic aspects of the disease. The infected mice displayed histopathological signs similar to human biliary atresia, with bile duct obstruction, bile duct proliferation, and liver inflammation with fibrosis.

Downregulation of Hes1 expression in experimental biliary atresia and its effects on bile duct structure

AIM

To analyze the expression and function of the Notch signaling target gene Hes1 in a rhesus rotavirus-induced mouse biliary atresia model.

METHODS

The morphologies of biliary epithelial cells in biliary atresia patients and in a mouse model were examined by immunohistochemical staining. Then, the differential expression of Notch signaling pathway-related molecules was investigated. Further, the effects of the siRNA-mediated inhibition of Hes1 expression were examined using a biliary epithelial cell 3D culture system.

RESULTS

Both immature (EpCAM⁺) and mature (CK19⁺) biliary epithelial cells were detected in the livers of biliary atresia patients without a ductile structure and in the mouse model with a distorted bile duct structure. The hepatic expression of transcripts for most Notch signaling molecules were significantly reduced on day 7 but recovered to normal levels by day 14, except for the target molecule Hes1, which still exhibited lower mRNA and protein levels. Expression of the Hes1 transcriptional co-regulator, RBP-Jκ was also reduced. A 3D gel culture system promoted the maturation of immature biliary epithelial cells, with increased expression of CK19⁺ cells and the formation of a duct-like structure. The administration of Hes1 siRNA blocked this process. As a result, the cells remained in an immature state, and no duct-like structure was observed.

CONCLUSION

Our data indicated that Hes1 might contribute to the maturation and the cellular structure organization of biliary epithelial cells, which provides new insight into understanding the pathology of biliary atresia.

HMGB1-promoted and TLR2/4-dependent NK cell maturation and activation take part in rotavirus-induced murine biliary atresia

Recent studies show that NK cells play important roles in murine biliary atresia (BA), and a temporary immunological gap exists in this disease. In this study, we found high-mobility group box-1 (HMGB1) and TLRs were overexpressed in human and rotavirus-induced murine BA. The overexpressed HMGB1 released from the nuclei of rotavirus-infected cholangiocytes, as well as macrophages, activated hepatic NK cells via HMGB1-TLRs-MAPK signaling pathways. Immature NK cells had low cytotoxicity on rotavirus-injured cholangiocytes due to low expression of TLRs, which caused persistent rotavirus infection in bile ducts. HMGB1 up-regulated the levels of TLRs of NK cells and promoted NK cell activation in an age-dependent fashion. As NK cells gained increasing activation as mice aged, they gained increasing cytotoxicity on rotavirus-infected cholangiocytes, which finally caused BA. Adult NK cells eliminated rotavirus-infected cholangiocytes shortly after infection, which prevented persistent rotavirus infection in bile ducts. Moreover, adoptive transfer of mature NK cells prior to rotavirus infection decreased the incidence of BA in newborn mice. Thus, the dysfunction of newborn NK cells may, in part, participate in the immunological gap in the development of rotavirus induced murine BA.

Biliary atresia (BA) is the most common precipitating factor for liver transplantation in infants. BA is caused by the obstruction of hepatic bile ducts, leading to progressive obstructive jaundice and liver fibrosis. A well-recognized theory is that rotavirus injures biliary epithelia in a mouse model of BA, followed by attack of immunocytes, such as NK cells. We performed this research to investigate whether maturation and activation of NK cells take part in the development of BA. We identified that rotavirus induced HMGB1 release from injured bile ducts. HMGB1 induced NK cell activation in an age-dependent fashion via HMGB1-TLRs-MAPK signaling pathways. Newborn NK cells were unable to eliminate rotavirus-infected cholangiocytes, which caused persistent biliary infection; maturated NK cells were activated gradually and caused persistent biliary injury, which finally led to BA. We identify HMGB1 as an important pro-inflammatory initiator and a critical inducer for maturation of NK cells in the development of BA. HMGB1-induced activation of NK cells may, in part, plays crucial roles in the development of murine BA. Novel therapies targeting HMGB1 or TLRs in patients with BA may be applied in the future to decrease the activity of NK cells in order to inhibit the progression of BA.

B cell deficient mice are protected from biliary obstruction in the rotavirus-induced mouse model of biliary atresia

A leading theory regarding the pathogenesis of biliary atresia (BA) is that bile duct injury is initiated by a virus infection, followed by an autoimmune response targeting bile ducts. In experimental models of autoimmune diseases, B cells have been shown to play an important role. The aim of this study was to determine the role of B cells in the development of biliary obstruction in the Rhesus rotavirus (RRV)-induced mouse model of BA. Wild-type (WT) and B cell-deficient (Ig-α(-/-)) mice received RRV shortly after birth. Ig-α(-/-) RRV-infected mice had significantly increased disease-free survival rate compared to WT RRV-infected BA mice (76.8% vs. 17.5%). In stark contrast to the RRV-infected BA mice, the RRV-infected Ig-α(-/-) mice did not have hyperbilirubinemia or bile duct obstruction. The RRV-infected Ig-α(-/-) mice had significantly less liver inflammation and Th1 cytokine production compared to RRV-infected WT mice. In addition, Ig-α(-/-) mice had significantly increased numbers of regulatory T cells (Tregs) at baseline and after RRV infection compared to WT mice. However, depletion of Tregs in Ig-α(-/-) mice did not induce biliary obstruction, indicating that the expanded Tregs in the Ig-α(-/-) mice were not the sole reason for protection from disease. Conclusion : B cell deficient Ig-α(-/-) mice are protected from biliary obstruction in the RRV-induced mouse model of BA, indicating a primary role of B cells in mediating disease pathology. The mechanism of protection may involve lack of B cell antigen presentation, which impairs T-cell activation and Th1 inflammation. Immune modulators that inhibit B cell function may be a new strategy for treatment of BA.

Silencing of the rotavirus NSP4 protein decreases the incidence of biliary atresia in murine model

Biliary atresia is a common disease in neonates which causes obstructive jaundice and progressive hepatic fibrosis. Our previous studies indicate that rotavirus infection is an initiator in the pathogenesis of experimental biliary atresia (BA) through the induction of increased nuclear factor-kappaB and abnormal activation of the osteopontin inflammation pathway. In the setting of rotavirus infection, rotavirus nonstructural protein 4 (NSP4) serves as an important immunogen, viral protein 7 (VP7) is necessary in rotavirus maturity and viral protein 4 (VP4) is a virulence determiner. The purpose of the current study is to clarify the roles of NSP4, VP7 and VP4 in the pathogenesis of experimental BA. Primary cultured extrahepatic biliary epithelia were infected with Rotavirus (mmu18006). Small interfering RNA targeting NSP4, VP7 or VP4 was transfected before rotavirus infection both in vitro and in vivo. We analyzed the incidence of BA, morphological change, morphogenesis of viral particles and viral mRNA and protein expression. The in vitro experiments showed NSP4 silencing decreased the levels of VP7 and VP4, reduced viral particles and decreased cytopathic effect. NSP4-positive cells had strongly positive expression of integrin subunit α2. Silencing of VP7 or VP4 partially decreased epithelial injury. Animal experiments indicated after NSP4 silencing, mouse pups had lower incidence of BA than after VP7 or VP4 silencing. However, 33.3% of VP4-silenced pups (N = 6) suffered BA and 50% of pups (N = 6) suffered biliary injury after VP7 silencing. Hepatic injury was decreased after NSP4 or VP4 silencing. Neither VP4 nor VP7 were detected in the biliary ducts after NSP4. All together, NSP4 silencing down-regulates VP7 and VP4, resulting in decreased incidence of BA.

Evolving biliary atresia with cytomegalovirus

Multiple studies have been conducted to demonstrate the role of viruses in causing biliary atresia. Although cytomegalovirus (CMV) is known to cause intrahepatic bile duct destruction, its role in biliary atresia is not proven. We report two cases of CMV infection, initially presenting with intrahepatic cholestasis, who subsequently developed biliary atresia.

Is there any association of extra hepatic biliary atresia with cytomegalovirus or other infections?

The objective of this study was to find any association of extrahepatic biliary atresia (EHBA) with a possible infectious etiology. Infants diagnosed to have EHBA were tested by blood PCR for cytomegalovirus (CMV), Ebstein-Barr virus, HBsAg, anti-HCV and IgM antibodies for CMV, toxoplasma, rubella, and herpes infections. Thirty-three infants of EHBA were included in the study, male 22, median age when diagnosed 2.5 months (range 1.0-5.0 months). On examination pallor, oedema and hepatosplenomegaly were seen in all and ascites and microcephaly in 19 (57.6%). Centile height and weight were 50th in 23 and 25th in 10. Persistent CMV infection documented by PCR was present in 14 (42%) patients. Eleven of these also had positive CMV IgM antibodies. No other above mentioned infections could be detected in our patients of EHBA. Our data suggests that CMV infection may play a role in the pathogenesis and progression of EHBA.

Role of interferon in homologous and heterologous rotavirus infection in the intestines and extraintestinal organs of suckling mice

Recent studies demonstrated that viremia and extraintestinal rotavirus infection are common in acutely infected humans and animals, while systemic diseases appear to be rare. Intraperitoneal infection of newborn mice with rhesus rotavirus (RRV) results in biliary atresia (BA), and this condition is influenced by the host interferon response. We studied orally inoculated 5-day-old suckling mice that were deficient in interferon (IFN) signaling to evaluate the role of interferon on the outcome of local and systemic infection after enteric inoculation. We found that systemic replication of RRV, but not murine rotavirus strain EC, was greatly enhanced in IFN-alpha/beta and IFN-gamma receptor double-knockout (KO) or STAT1 KO mice but not in mice deficient in B- or T-cell immunity. The enhanced replication of RRV was associated with a lethal hepatitis, pancreatitis, and BA, while no systemic disease was observed in strain EC-infected interferon-deficient mice. In IFN-alpha/beta receptor KO mice the extraintestinal infection and systemic disease were only moderately increased, while RRV infection was not augmented and systemic disease was not present in IFN-gamma receptor KO mice. The increase of systemic infection in IFN-deficient mice was also observed during simian strain SA11 infection but not following bovine NCDV, porcine OSU, or murine strain EW infection. Our data indicate that the requirements for the interferon system to inhibit intestinal and extraintestinal viral replication in suckling mice vary among different heterologous and homologous rotavirus strains, and this variation is associated with lethal systemic disease.

Integrin alphavbeta6 and mediators of extracellular matrix deposition are up-regulated in experimental biliary atresia

INTRODUCTION

Biliary atresia (BA) is a progressive obliteration of the extrahepatic bile ducts resulting in hepatic fibrosis. The underlying mechanisms have not been defined. We used an animal model of BA to evaluate mediators of extracellular matrix (ECM) processing to determine which factors may be involved.

METHODS

Newborn BALB/c mice received an intraperitoneal injection with rhesus rotavirus or saline within 24 h of birth. Livers were harvested on days 7 and 14 for histology and immunohistochemistry (IHC). RNA expression was determined using quantitative real-time PCR. Human liver from patients with BA and those having a resection for nonfibrosing diseases was also evaluated.

RESULTS

In experimental mice, mRNA expression for tissue inhibitor of metalloproteinase (TIMP)-1 and matrix metalloproteinase (MMP)-7 was increased 18-fold and 69-fold, respectively on day 7, with further increases on day 14. On day 14, mRNA expression for plasminogen activator inhibitor (PAI)-1 (38-fold), TIMP-4 (9.5-fold), and MMP-9 (5.5-fold) mRNA was also observed. Furthermore, integrin alpha(v) beta(6) mRNA expression was increased on days 7 (11-fold) and 14 (6-fold). Presence of integrin alpha(v) beta(6) protein was confirmed by IHC in both mouse and human specimens in the proliferating biliary epithelium.

CONCLUSIONS

Our data suggest experimental BA is associated with increased mRNA expression of ECM degradation inhibitors, TIMP-1, PAI-1, and TIMP-4. MMP-7 and MMP-9 expression is also elevated in this model. Furthermore, increased gene expression of integrin alpha(v)beta(6) was demonstrated and IHC confirmed protein expression. Integrin alpha(v)beta(6) or the inhibitors of ECM breakdown may be attractive targets for future treatment strategies.

Innate immune response to double-stranded RNA in biliary epithelial cells is associated with the pathogenesis of biliary atresia

Infections of Reoviridae consisting of a double-stranded RNA (dsRNA) genome are a possible cause of biliary atresia (BA). The aim of the present study is to clarify the pathophysiological function of dsRNA viruses in the pathogenesis of BA. The expression of dsRNA pattern-recognizing receptors, Toll-like receptor 3 (TLR3), retinoic acid inducible gene I (RIG-I), melanoma differentiation-associated gene-5 (MDA-5), and dsRNA-activated protein kinase R (PKR) was constitutively detected in cultured human biliary epithelial cells (BECs). Stimulation with polyinosinic-polycytidylic acid [poly(I:C), a synthetic analog of viral dsRNA] induced the activation of transcription factors [nuclear factor (NF)-kappaB and interferon regulatory factor 3 (IRF3)] and the production of interferon-beta1 (IFN-beta1) and MxA as potent antiviral responses. Moreover, poly(I:C) up-regulated the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), and both poly(I:C) and TRAIL reduced the viability of cultured human BECs by enhancing apoptosis. Experiments in vivo using tissue sections of extrahepatic bile ducts from patients with BA and controls (choledochal cysts and nonbiliary diseases) showed that the activation of NF-kappaB, interferon regulatory factor-3 (IRF-3), and PKR, and the enhancement of TRAIL and single-stranded DNA (ssDNA)-positive apoptosis were significant in BA, although extrahepatic bile ducts diffusely and constantly expressed TLR3 in all diseases.

CONCLUSION

dsRNA viruses could directly induce the expression of TRAIL and apoptosis in human biliary epithelial cells as a result of the biliary innate immune response, supporting the notion that Reoviridae infections are directly associated with the pathogenesis of cholangiopathies in cases of BA.

MAPK signaling contributes to rotaviral-induced cholangiocyte injury and viral replication

BACKGROUND

Biliary atresia is a disease of newborns that results in obliteration of the biliary tree. Infection of mice with rhesus rotavirus (RRV) results in a cholangiopathy mirroring human disease. The Mitogen Associated Protein Kinase (MAPK) signaling pathway can be activated by viral binding to cell-surface receptors. We hypothesized that RRV infection of cholangiocytes results in activation of MAPK signaling.

METHODS

Extrahepatic bile ducts from BALB/c pups or immortalized cholangiocytes subjected to RRV infection or control were analyzed, using Western blots, for phosphorylated members of the MAPK family: p38, ERK 1/2, JNK 1/2, and downstream transcription factors. Inhibitors of the MAPK were used to downregulate activity. Viral replication and cytolysis in cholangiocytes were evaluated post-MAPK inhibition.

RESULTS

Phosphorylation of all MAPK increased in RRV-infected mice and cholangiocytes. Several downstream transcription factors had increased activity in vitro. Inhibition of p38 and ERK 1/2 resulted in decreased viral replication. ERK 1/2 inhibition decreased cytolysis without affecting viral entry or binding.

CONCLUSIONS

RRV infection of cholangiocytes resulted in increased MAPK signaling. Inhibition of p38 and ERK 1/2 influenced the ability of rotavirus to replicate. These novel findings provide insight into the signaling cascade involved in RRV-induced cholangiocyte injury.

The pathogenesis of biliary atresia: evidence for a virus-induced autoimmune disease

Biliary atresia is a mystifying cause of neonatal cholestasis, manifested by progressive inflammation and fibrosis of both the extrahepatic and intrahepatic bile ducts. It is a devastating disease that leads to cirrhosis and the need for liver transplantation in the majority of children. The etiology is unknown, and one theory is that it may involve a primary perinatal hepatobiliary viral infection and a secondary generation of an autoimmune-mediated bile duct injury. This review will outline the evidence from both human and murine studies supporting a potential cholangiotropic viral infection as the initiator of bile duct injury in biliary atresia and the role of the adaptive immune response and autoimmunity in progression of disease. Delineating the pathways of immune and autoimmune-mediated bile duct injury within biliary atresia could stimulate development of new medical interventions aimed at suppressing the specific immune response, decreasing the inflammatory damage to bile ducts, and delaying or negating the need for liver transplantation.

Effector role of neonatal hepatic CD8+ lymphocytes in epithelial injury and autoimmunity in experimental biliary atresia

BACKGROUND & AIMS

Lymphocytes populate the livers of infants with biliary atresia, but it is unknown whether neonatal lymphocytes regulate pathogenesis of disease. Here, we investigate this question by examining the role of T lymphocytes in the destruction of extrahepatic bile ducts of neonatal mice using an experimental model of biliary atresia.

METHODS

Inoculation of neonatal mice with rhesus rotavirus followed by multistaining flow cytometry to quantify expression of interferon-gamma by hepatic lymphocytes, and real-time polymerase chain reaction for mRNA expression of pro-inflammatory cytokines. This was followed by determining the consequences of antibody-mediated depletion of lymphocyte subtypes on the development of biliary obstruction, and coculture and cell transfer experiments to investigate the effector role of lymphocyte subtypes on neonatal biliary disease.

RESULTS

Rotavirus infection results in overexpression of interferon-gamma by neonatal hepatic T cells. Among these cells, depletion of CD4(+) cells did not change the course of inflammatory injury and obstruction of neonatal bile ducts. In contrast, loss of CD8(+) cells remarkably suppressed duct injury, prevented luminal obstruction, and restored bile flow. Coculture experiments showed that rotavirus-primed, but not naïve, CD8(+) cells were cytotoxic to cholangiocytes. In adoptive transfer experiments, we found that primed CD8(+) cells preferentially homed to extrahepatic bile ducts of neonatal mice and invaded their epithelial lining.

CONCLUSIONS

Primed neonatal CD8(+) cells can activate a pro-inflammatory program, target diseased and healthy duct epithelium, and drive the phenotypic expression of biliary atresia, thus constituting a potential therapeutic target to halt disease progression.

Characterization of erythrovirus B19 genomes isolated in liver tissues from patients with fulminant hepatitis and biliary atresia who underwent liver transplantation

BACKGROUND

Fulminant hepatitis and biliary atresia are serious problems and their causes have not been explained well. We investigated whether or not erythrovirus B19 is a candidate etiologic agent in such liver disease patients who had undergone liver transplantation.

METHODS

Liver tissues from 47 patients consisted of 28 fulminant hepatitis and 19 biliary atresia were examined to detect B19 genes by PCR and further analyzed their genomic characterization.

RESULTS

B19 DNA was detected by nested PCR in 10 of 28 cases (35.7%) livers in the fulminant hepatitis group and 7 of 19 (36.8%) livers in the biliary atresia group, respectively (statistically not significant). Importantly, among the 8 hepatic B19 DNA-positive patients who had paired samples of liver and serum, the serum B19 genome was detectable in only one case. B19 mRNA was identified in all of 10 fulminant hepatitis cases with hepatic B19 DNA, but only 1 out of 7 (14.3%) cases in biliary atresia tested. Furthermore, we obtained ten isolates having the B19 genome with nearly full-length sequences. Interestingly, phylogenetic analysis based on the NS1 gene revealed three different clusters: two for isolates from fulminant hepatitis and the other for isolates from biliary atresia.

CONCLUSIONS

Our results presented here suggested that B19 may be an etiologic agent of fulminant hepatitis.

Effect of rotavirus strain on the murine model of biliary atresia

Biliary atresia is a devastating disorder of the newborn in which afflicted infants develop inflammation and fibrosis of the extrahepatic biliary tract, resulting in cirrhosis and end-stage liver disease. Infection with a virus is thought to be a contributing factor in the etiology of biliary atresia. In the murine model of biliary atresia, perinatal exposure to rhesus rotavirus (RRV) results in biliary epithelial cell infection causing bile duct obstruction. The purpose of this study was to determine if tropism for the biliary epithelial cell was unique to RRV. Newborn mice underwent intraperitoneal injection with five strains of rotavirus: RRV (simian), SA11-FM (simian/bovine), SA11-SM (simian), EDIM (murine), and Wa (human). RRV and SA11-FM caused clinical manifestations of bile duct obstruction and high mortality. SA11-SM caused clinical signs of hepatobiliary injury but the mortality was markedly reduced. EDIM and Wa caused no sign of hepatobiliary disease. The systemic and temporal distribution of viral protein and live virus varied according to the injected strain. Immunohistochemistry revealed that RRV and SA11-FM targeted the biliary epithelial cells. In contrast, SA11-SM was found in the liver but in not in the biliary epithelium. These results indicate that strain-specific characteristics dictate tropism for cells of hepatobiliary origin which in turn impact the ability to induce the murine model of biliary atresia.

Loss of interleukin-12 modifies the pro-inflammatory response but does not prevent duct obstruction in experimental biliary atresia

Background

Livers of infants with biliary atresia and of neonatal mice infected with rotavirus (RRV) have increased expression of interferon-gamma (IFNγ) and interleukin (IL)-12. While the expression of IFNγ regulates the obstruction of extrahepatic bile ducts by lymphocytes, the role of IL-12 in the pathogenesis of biliary obstruction is unknown. Based on the role of IL-12 as a key proinflammatory cytokine, we hypothesized that loss of IL-12 prevents the obstruction of extrahepatic bile ducts.

Methods

IL12-knockout (IL-12KO) and wild type mice were injected with RRV or saline at day 1 of age and monitored for the development of symptoms. The cellular and molecular phenotypes were determined at days 3, 7, and 14 by real-time PCR and flow cytometry.

Results

RRV infection of IL-12KO mice resulted in growth failure, jaundice/acholic stools, and decreased survival similar to wild-type mice. IL-12KO mice had a remarkable neutrophil-rich portal inflammation and epithelial sloughing of extrahepatic bile ducts. Loss of IL-12 decreased but did not abolish the hepatic expression of IFNγ, displayed a remarkable increase in expression of TNFα, IFNα, IFNβ and decreased expression of IL-4 and IL-5.

Conclusion

Loss of IL-12 did not modify the progression of bile duct obstruction in experimental biliary atresia. However, the inflammatory response was predominantly neutrophil-based and displayed a Th1 response in the absence of IL-12.

Gene expression profile of the infective murine model for biliary atresia

One hypothesis of the pathogenesis of biliary atresia (BA) is a virus-induced and immune-mediated injury to bile duct cells as mimicked in the rotavirus-induced murine model. This theory is supported by studies showing a predominant T helper cell response type 1-like phenotype of inflammation with increased interferon gamma-induced chemokines in the liver of humans and mice suffering from BA. Recent gene expression profiling studies using microarray analysis showed the induction of a proinflammatory state in human liver specimens with high analogies in extrahepatic biliary tissue of BA mice. The aim of the present study was a microarray analysis of gene expression in the liver of Balb/c mice, comparing infected mice that show the phenotype of BA versus infected mice without symptoms, thus trying to elucidate genes that are not related to the viral origin of this model, but to the specific pathogenesis of the clinical picture of BA. Fifteen mug of RNA, each of three BA-positive and three BA-negative mice, were pooled and comparatively hybridized to spotted cDNA microarrays containing 250 key genes with high relevance to immunological settings. We identified the 40 genes most differentially expressed in mice with and without BA. The majority of genes with higher expression in BA-positive mice encoded proinflammatory cytokines involved in the Th1 pathway, such as CCL2, CCL5, CCR5, CXCL10, CCL2, IL1F5 and in apoptosis, such as DDR3 and granzyme A and B. In this initial study of the molecular characterization of our RRV-induced BA mouse model system, we also found potential novel candidates important to BA etiology, such as growth hormone receptor and insulin-like growth factor. Of particular interest, very low expression of TIMD2 was observed in BA-positive mice. TIMD2 plays a critical role in the regulation of a Th2-type response through the inhibition of IFN gamma.

High frequency of human cytomegalovirus DNA in the liver of infants with extrahepatic neonatal cholestasis

Background

Biliary atresia (BA) is the most severe hepatic disorder in newborns and its etiopathogenesis remains unknown. Viral involvement has been proposed, including the human cytomegalovirus (HCMV). The aims of the study were to use the polymerase chain reaction (PCR) to screen the liver tissue of infants with extrahepatic cholestasis for HCMV and to correlate the results with serological antibodies against HCMV and histological findings.

Methods

A retrospective study in a tertiary care setting included 35 patients (31 BA, 1 BA associated with a choledochal cyst, 2 congenital stenosis of the distal common bile duct and 1 hepatic cyst). HCMV serology was determined by ELISA. Liver and porta hepatis were examined histologically. Liver samples from infants and a control group were screened for HCMV DNA.

Results

Twelve patients had HCMV negative serology, 9 were positive for IgG antibodies and 14 were positive for IgG and IgM. Nine liver and seven porta hepatis samples were positive for HCMV DNA but none of the control group were positive (general frequency of positivity was 34.3% – 12/35). There was no correlation between HCMV positivity by PCR and the histological findings. The accuracy of serology for detecting HCMV antibodies was low.

Conclusion

These results indicate an elevated frequency of HCMV in pediatric patients with extrahepatic neonatal cholestasis. They also show the low accuracy of serological tests for detecting active HCMV infection and the lack of correlation between HCMV positivity by PCR and the histopathological changes.

Computerized three-dimensional study of a rotavirus model of biliary atresia: comparison with human biliary atresia

Biliary atresia is a panbiliary disease causing obstructive jaundice in neonates and infants. The clinical spectrum can be broadly categorized into the fetal and perinatal types. A consistent animal model that accurately mimics the whole clinical spectrum of biliary atresia is not yet available. However, rotavirus infection of neonatal mice has been shown to produce atresia in the biliary system. This study investigates the three-dimensional computerized morphology of the murine neonatal model comparing with age-matched control mice. Newborn Balb/c mice were injected intraperitoneally with rhesus rotavirus within 24-48 h after birth. Control mice received 0.9% NaCl. Pups with symptoms of cholestasis were sacrificed from the 5th to the 15th postinjection day, as were age-matched controls. Their hepatobiliary tissues were prepared for three-dimensional computerized image reconstruction. Rotavirus infection caused obliteration of the intrahepatic bile ducts and single to multiple atresias in the extrahepatic bile duct. At 15 days postinjection, intrahepatic ductal proliferation appeared, and the three-dimensional appearances of the intrahepatic biliary structures were similar to the human disease. Cystic duct and gallbladder dilatation was frequently seen in this model, and this feature distinguishes it from the human disease in which the gallbladder is almost always atretic. This rotavirus murine model demonstrates many of the features of human perinatal biliary atresia, and can be used as an investigative tool to further study the pathogenesis of biliary atresia.

Extrahepatic bile duct atresia and viral involvement

Several etiological factors have been suggested in the pathogenesis of extrahepatic biliary atresia (EHBA); congenital, metabolic, infectious, and multifactorial. Herein we present a study of 10 children with EHBA, the aim being to explore viral infection as a possible cause of their condition. During a period of 2 yr, all infants with EHBA were included in a study and examined on viral disease on admittance for Kasai operation. In eight of the 10 children and in one parental couple the laboratory results suggested recent or persistent viral infection. Four infections were caused by cytomegalovirus (CMV) and another five by Epstein-Barr virus (EBV). CMV-DNA was detected in two liver biopsies, EBV-DNA in one liver biopsy. In a control group of 10 patients matched by age and tested by PCR in serum and viral antibodies, no sign of viral infections were detected. CMV or EBV infection were present in an unexpectedly high proportion of infants with EHBA, justifying exhaustive examination on viral disease in these children.

Obstruction of extrahepatic bile ducts by lymphocytes is regulated by IFN-gamma in experimental biliary atresia

The etiology and pathogenesis of bile duct obstruction in children with biliary atresia are largely unknown. We have previously reported that, despite phenotypic heterogeneity, genomic signatures of livers from patients display a proinflammatory phenotype. Here, we address the hypothesis that production of IFN-gamma is a key pathogenic mechanism of disease using a mouse model of rotavirus-induced biliary atresia. We found that rotavirus infection of neonatal mice has a unique tropism to bile duct cells, and it triggers a hepatobiliary inflammation by IFN-gamma-producing CD4(+) and CD8(+) lymphocytes. The inflammation is tissue specific, resulting in progressive jaundice, growth failure, and greater than 90% mortality due to obstruction of extrahepatic bile ducts. In this model, the genetic loss of IFN-gamma did not alter the onset of jaundice, but it remarkably suppressed the tissue-specific targeting of T lymphocytes and completely prevented the inflammatory and fibrosing obstruction of extrahepatic bile ducts. As a consequence, jaundice resolved, and long-term survival improved to greater than 80%. Notably, administration of recombinant IFN-gamma led to recurrence of bile duct obstruction following rotavirus infection of IFN-gamma-deficient mice. Thus, IFN-gamma-driven obstruction of bile ducts is a key pathogenic mechanism of disease and may constitute a therapeutic target to block disease progression in patients with biliary atresia.

Lack of evidence for reovirus infection in tissues from patients with biliary atresia and congenital dilatation of the bile duct

BACKGROUND/AIMS

To clarify the association between the reovirus infection of the hepatobiliary tree and the development of infantile obstructive cholangiopathy (IOC) including biliary atresia (BA) and congenital dilatation of the bile duct (CBD).

METHODS

We designed reovirus common primers for nested RT-PCR based on the L3 gene segment. The spectrum and the sensitivity of common primers were evaluated with purified reoviral RNAs and reovirus mixed with stool samples. Then, nested RT-PCRs were performed with hepatobiliary and fecal samples obtained from patients with BA, CBD, and control diseases. Additionally, electron microscopy of stool samples was performed.

RESULTS

The L3 common primers could amplify cDNAs synthesized from RNAs of three prototypes of reovirus, and detect as much as 5.0x10(3) plaque forming unit of serotype 3 Dearing strain in 100 mg of fecal samples. However, no amplification product was detected in 136 hepatobiliary tissues taken from 67 patients including 26 BAs and 28 CBDs, or in 65 fecal samples obtained from 15 patients including 10 BAs and 1 CBD. Additionally, viral particles were not found in any stool specimens by the electron microscope.

CONCLUSIONS

These data do not suggest that reoviruses play a major role in the etiology of IOC or BA.

Role of some viral infections in neonatal cholestasis

Viral infection is one of the postulated causes of neonatal cholestasis. In addition to earlier reports on the association of viral infection and intrahepatic cholestasis (IH), recent studies have suggested a similar link to extra hepatic biliary atresia (EHBA). The aim of this work was to evaluate the role of some viral infections in neonates presenting with cholestasis to the Neonatology Ward of Zagazig University Hospitals. Sixty-two neonates were included in the study (44 cholestatic neonates and 18 apparently healthy neonates as the control group). All neonates were subjected to full history taking and complete physical examination. Laboratory investigations included CBC, liver function tests, bleeding profile, blood cultures, abdominal ultrasound and detection of HBsAg and serum IgM antibodies against certain viruses (CMV, Reovirus III, HSV I, HSV II, Rubella virus) using ELISA. Radionuclide cholescintigraphy was performed for patients only. The study revealed that cholestatic neonates were significantly associated with dark urine, pale stool and hepatomegaly compared with the control (P<0.004, P<0.001, P<0.008, respectively). Quantitation of IgM antibody titre using ELISA revealed significantly higher levels of serum anti-CMV IgM and anti-Reovirus III IgM in cholestatic than in the control groups. No significant differences were found in levels of anti-HSV I, anti-HSV II or anti-rubella antibodies between cholestatic and control groups. HBsAg was negative for all neonates; cholestatic and control. Lastly, no significant differences were found between neonates with EHBA (7 cases) and Intrahepatic cholestasis (37 cases) regarding anti -CMV IgM or anti -Reo III IgM. It can be concluded that CMV and Reovirus type 3 infections of the neonates are associated with the development of cholestatic disorder, not only due to IH cholestasis but also due to the production of EHBA.

Utilization of sialic acid as a coreceptor is required for reovirus-induced biliary disease

Infection of neonatal mice with some reovirus strains produces a disease similar to infantile biliary atresia, but previous attempts to correlate reovirus infection with this disease have yielded conflicting results. We used isogenic reovirus strains T3SA- and T3SA+, which differ solely in the capacity to bind sialic acid as a coreceptor, to define the role of sialic acid in reovirus encephalitis and biliary tract infection in mice. Growth in the intestine was equivalent for both strains following peroral inoculation. However, T3SA+ spread more rapidly from the intestine to distant sites and replicated to higher titers in spleen, liver, and brain. Strikingly, mice infected with T3SA+ but not T3SA- developed steatorrhea and bilirubinemia. Liver tissue from mice infected with T3SA+ demonstrated intense inflammation focused at intrahepatic bile ducts, pathology analogous to that found in biliary atresia in humans, and high levels of T3SA+ antigen in bile duct epithelial cells. T3SA+ bound 100-fold more efficiently than T3SA- to human cholangiocarcinoma cells. These observations suggest that the carbohydrate-binding specificity of a virus can dramatically alter disease in the host and highlight the need for epidemiologic studies focusing on infection by sialic acid-binding reovirus strains as a possible contributor to the pathogenesis of neonatal biliary atresia.

The M2 gene segment is involved in the capacity of reovirus type 3Abney to induce the oily fur syndrome in neonatal mice, a S1 gene segment-associated phenotype

Oral inoculation of reovirus type 3 Abney (T3A) into neonatal mice induces hepatitis and the biliary atresia-associated oily fur syndrome (OFS), a phenotype previously linked to the S1 gene. We found that following oral inoculation, none of three T3A mutants, JH2, JH3, and JH4, containing different single amino acid substitutions in the M2 gene, induced the OFS or extensive liver necrosis. Similarly, reassortant viruses containing both a JH4-S1 and a JH4-M2 gene segment did not induce the OFS, whereas another reassortant containing a JH4-S1 gene and a M2 gene from reovirus type 3 Dearing fully recovered this capacity. Together, these results constitute the first evidence for the involvement of the M2 gene in the S1 gene-associated capacity of T3A to induce hepatobiliary disease in neonatal mice.

The role of reovirus type 3 infection in an established murine model for biliary atresia

AIM OF THE STUDY

Infection of newborn Balb/c-mice with Rhesus rotavirus (RRV) leads to cholestasis and biliary atresia. In this current model, Reovirus Type 3 was investigated to ascertain whether Reovirus Type 3 causes the same or similar hepatobiliary lesions as RRV.

METHODS

Newborn Balb/c-mice were infected with Reovirus Type 3 Dearing and Reovirus Type 3 Abney on the first day of life. Clinical observation followed for a period of at least 10 days. Cholestatic and/or dystrophic mice were prepared and specimens were taken for histological examination.

RESULTS

Infection with RRV showed a 85 % morbidity for biliary atresia as described before. Clinical disease, following an infection with Reovirus T3 Dearing, showed neurological symptoms such as ataxia, and all mice died within 3 weeks. No obstructive or atretic changes of the hepatobiliary ducts could be seen either macroscopically or histomorphologically. 60 % of the mice having been infected with Reovirus T3 Abney showed signs of cholestasis and oily fur syndrome, but almost 15 % recovered from the disease. Although the histological findings did not reveal biliary atresia, inflammation and destruction of bile ducts could be observed.

CONCLUSION

In comparison to the RRV infection in a Balb/c-mice model, where biliary atresia could be induced, infection with Reovirus T3 in this model did not lead to biliary atresia. But Reovirus T3 Abney infection revealed inflammatory signs as described in the literature before. The question as to why different hepatotrophic viruses lead to different changes in the murine hepatobiliary tract has to be investigated in further studies.

Biliary atresia and cytomegalovirus infection: a DNA study

The cause of extrahepatic biliary atresia (EHBA) is undetermined in most instances, but an infectious agent is widely suspected. Cytomegalovirus (CMV) infection has been associated with intrahepatic bile duct destruction and paucity, raising the question of its role in EHBA. We identified 12 children in the past 5 years with biliary atresia and examined the bile duct biopsy. These showed acute/chronic inflammation and epithelial degeneration. CMV inclusions were not identified. We used in situ hybridization and the polymerase chain reaction (PCR) for CMV-DNA on formalin-fixed, paraffin-embedded tissue. All samples showed the presence of amplifiable DNA using beta-globin primers. No biopsy tissue showed CMV DNA using specific probes and primers. The absence of demonstrable CMV DNA by in situ hybridization and PCR in EHBA biopsies implies that it is unlikely that this virus has any major role in the pathogenesis of this condition.

Presence of human papillomavirus in extrahepatic biliary atresia

BACKGROUND

In a previous study the human papillomavirus DNA was detected in seven cases of so-called idiopathic neonatal giant cell hepatitis by using nested polymerase chain reaction. The purpose of the present study was to study the prevalence and possible common causes of human papillomavirus-associated idiopathic neonatal giant cell hepatitis and extrahepatic biliary atresia.

METHODS

Formalin-fixed, paraffin-embedded archival tissues obtained in 18 cases of extrahepatic biliary atresia were studied for human papillomavirus DNA by nested polymerase chain reaction. In addition, in situ hybridization was performed on tissue obtained in 6 cases.

RESULTS

Tissue in 16 of the 18 cases studied showed amplified human papillomavirus DNA, whereas no human papillomavirus was amplified in any of 30 control samples. Main human papillomaviruses detected were types 6 and 18. Punctate intranuclear positive signals were detected in the hepatocytes after in situ hybridization for human papillomavirus DNA.

CONCLUSIONS

The high prevalence of human papillomavirus DNA in liver tissue in cases of extrahepatic biliary atresia suggests a strong correlation between this disorder and idiopathic neonatal giant cell hepatitis. It further suggests that this virus may be one of the causative agents in extrahepatic biliary atresia and may represent part of the spectrum of lesions associated with neonatal human papillomavirus-induced hepatic damage.

The viral association of neonatal cholestasis in Sweden: a possible link between cytomegalovirus infection and extrahepatic biliary atresia

BACKGROUND

In addition to earlier reports on the association between viral infections and intrahepatic neonatal cholestasis, in recent studies, investigators have suggested a similar link to extrahepatic biliary atresia.

METHODS

Fifty-nine cholestatic infants (mean age 8 weeks) were investigated for signs of infection with a large spectrum of viruses. Twenty-one infants had extrahepatic biliary atresia, 38 had intrahepatic cholestasis. The virologic methods included serologic investigation in 59 infants and 54 mothers, virus isolation from stools (49 infants), urine (58 infants) and liver biopsies (40 infants). Polymerase chain reaction was used to detect cytomegalovirus DNA in 25 of the liver biopsy specimens. Two control groups, one with 35 noncholestatic infants and one with 111 healthy, pregnant women were checked for serologic signs of cytomegalovirus.

RESULTS

Nineteen of 59 (32%) cholestatic infants, including 8 of 21 (38%) with extrahepatic biliary atresia, compared with 2 of 35 (6%) control infants had cytomegalovirus-immunoglobulin (Ig) M detected in serum (p < 0.01). Fifty-one of 54 (94%) tested mothers of cholestatic infants were seropositive for cytomegalovirus, compared with 83 of 111 (75%) control mothers (p < 0.01). Cytomegalovirus DNA in liver specimens was detected by polymerase chain reaction in 9 of 18 (50%) analyzed patients with biliary atresia and in specimens from 3 of 7 patients with intrahepatic cholestasis.

CONCLUSIONS

Cytomegalovirus infection may play a role, not only in intrahepatic neonatal cholestasis, as was suggested earlier, but also in extrahepatic biliary atresia. The pathogenetic mechanism for this link remains to be established.

[Human papillomavirus, neonatal giant cell hepatitis and biliary duct atresia]

We previously recognized the presence of HPV-DNA in cases of idiopathic neonatal giant cell hepatitis (INGCH) and extrahepatic biliary duct atresia (EBDA) in archivated tissue using the PCR technique. In order to investigate a possible vertical transmission we looked for the presence of HPV-DNA in cervical swabs in the mothers along with formalin-fixed paraffin-embedded hepatic tissue from 3 infants with INGCH and 4 patients with EBDA by nested-PCR. Cervical smears showed koilocytosis consistent with HPV infection in 2 cases. Delivery was vaginal except for one that was by cesarean section. All infants were males. Amplification of HPV-DNA was demonstrated in all cases, the types being concordant in infants and mothers. Although this is a small group, the findings appear in line with previous data. The presence of the same type of HPV-DNA in the infants' livers and their mothers' cervical swabs is another argument supporting the possibility of vertical transmission of the virus.

Detection of reovirus RNA in hepatobiliary tissues from patients with extrahepatic biliary atresia and choledochal cysts

Extrahepatic biliary atresia (EHBA) and choledochal cysts (CDC) are important causes of obstructive jaundice in pediatric patients. Viruses in general, and reoviruses in particular, have long been considered as possible etiologic agents responsible for inciting the inflammatory process that leads to these infantile obstructive cholangiopathies. In an effort to determine whether reovirus infection is associated with these disorders, we used a sensitive and specific reverse-transcriptase polymerase chain reaction (RT-PCR) technique designed to amplify a portion of the reovirus L1 gene segment from extracts of liver and/or biliary tissues. These tissues were obtained at the time of liver biopsy or surgical procedures from 23 patients with EHBA, 9 patients with CDC, and 33 patients with other hepatobiliary diseases. Hepatic and biliary tissues obtained at autopsy from 17 patients who died without known liver or biliary disease were also analyzed. Reovirus RNA was detected in hepatic and/or biliary tissues from 55% of patients with EHBA and 78% of patients with CDC. Reovirus RNA was found also in extracts of hepatic and/or biliary tissue from 21% of patients with other hepatobiliary diseases and in 12% of autopsy cases. The prevalence of reovirus RNA in tissues from patients with EHBA and CDC was significantly greater than that in patients with other hepatobiliary diseases (chi2 P = .012 EHBA vs. OTHER, P = .001 CDC vs. OTHER), or AUTOPSY cases (chi2 P = .006 EHBA vs. AUTOPSY, P < .001 CDC vs. AUTOPSY).

Diverse morphology of biliary atresia in an animal model

BACKGROUND/AIMS

Extrahepatic biliary atresia can be simulated in Balb/c-mice which have been infected with rotavirus. Irreversible occlusion of the common bile duct is the result of an inflammatory process of the whole biliary tract. The observations in this animal model are similar to extrahepatic biliary atresia in newborn children. The present study describes the wide range of morphological findings in mice and compares the results with several classifications of extrahepatic biliary atresia in children.

METHODS

Newborn Balb/c-mice were infected intraperitoneally with rhesus rotavirus; the pathological morphology of the extrahepatic bile ducts in 73 mice is described and illustrated by scanning electron microscopy.

RESULTS

The extension and localisation of atresia varied from short to interrupted or long-segment atresia, with or without prestenotic dilatation. The gallbladder was small and atretic, or appeared hydropic due to atresia of the common bile duct. The wide range of pathomorphological findings is the final stage of an inflammatory process. The morphological changes of the extrahepatic bile ducts do not fit any pattern, and no classification is evident.

CONCLUSIONS

Most types of extrahepatic biliary atresia in children can be mimicked in this animal model. Comparing these observations with different classifications of extrahepatic biliary atresia in children, it must be asked if any classification of the disease is justified, having regard only to pathomorphological findings in the extrahepatic biliary tract.

Treatment of extrahepatic biliary atresia with interferon-alpha in a murine infectious model

The etiology of extrahepatic biliary atresia (EHBA) in newborns remains unknown, although a first infectious animal model with complete obstruction of the common bile duct could be established. Intraperitoneal inoculation of newborn Balb/c mice with rhesus rotavirus induced cholestasis, leading, in most cases, to biliary atresia with lethal outcome, similar to EHBA in human newborns. The influence of interferon-alpha (IFN-alpha) on the hepatotropism of rotavirus infection was investigated in this animal model. Single-dose therapy with 10000 IU of IFN-alpha protected all rhesus rotavirus-infected pups from cholestatic disease. The same dose, injected 5 d after infection, had no protective effect. Starting with onset of cholestatic symptoms, the treatment with 10000 IU of IFN-alpha daily showed good results in 29 mice. Seventy-six percent of the mice recovered after 1 wk of therapy. Histologic investigation revealed normal findings in the hepatobiliary tract of clinically normal mice. Twenty-one percent of the descendants of infected and prophylactic IFN-alpha-treated mice showed cholestatic symptoms after infection with rhesus rotavirus (79% in an untreated control group) and a milder form of the illness. In conclusion, we found that prophylactic treatment with IFN-alpha prevented the hepatobiliary system of newborn Balb/c mice from severe damage by rhesus rotavirus in this artificially designed infectious model for EHBA. Infected and icteric mice, treated for 1 wk with IFN-alpha, had good prospects for recovery and prevention of complete and irreversible occlusion of the extrahepatic bile ducts. Infected and prophylactic IFN-alpha-treated dams gave good protection to their descendants. This means that EHBA in this model could probably be averted by maternal antibodies against rotavirus.

Lack of evidence for rotavirus by polymerase chain reaction/enzyme immunoassay of hepatobiliary samples from children with biliary atresia

The purpose of this study was to analyze hepatobiliary samples of patients with biliary atresia for rotavirus groups. A, B, and C, because group A rotavirus had been used to produce an animal model of the disease and group C rotavirus had been found in hepatobiliary samples from one group of patients. Biliary remnants and liver tissue from 10 biliary atresia and 14 control patients with other liver diseases were examined for rotavirus groups A, B, and C using nonisotopic, reverse transcriptase polymerase chain reaction enzyme immunoassay. Biliary atresia patients had a median age of 3 mo and were from a confined geographic area. Rotaviral stocks from groups A and C were used as polymerase chain reaction-positive controls. The limits of detection for rotaviral RNA from these two groups were respectively, 5 plaque-forming units and 50 tissue culture infectious doses (ID50). Tissue culture was 100-fold less sensitive for groups A and C than the polymerase chain reaction. The nested nonisotopic probes hybridized in solution only with their homologous target DNAs as determined by the enzyme immunoassay, or by Southern blot hybridization. Although it was possible to detect mRNA from a beta-actin housekeeping gene in all of the hepatobiliary samples, no evidence of rotaviral RNA was found in either the biliary atresia or the negative control group. In conclusion, rotavirus is not a common viral etiology of biliary atresia.

Detection of group C rotavirus in infants with extrahepatic biliary atresia

The purpose of this retrospective study was to examine liver tissue from patients with cholestatic disease for the presence of group C rotavirus RNA. The reverse transcriptase-polymerase chain reaction (PCR) for genes 5 and 6 was used, and the PCR products were subjected to liquid hybridization with a 32P-labeled probe. A second amplification with nested primers was also used. Samples from 32 subjects (20 with biliary atresia or choledochal cyst and 12 controls) were tested. Ten of 20 biliary atresia patients were positive for group C rotavirus RNA; no controls were positive (P < .003). Three of the positive patients were positive for both genes 5 and 6. Six of the 10 had > 1 sample that was positive. These data suggest a possible relationship between group C rotavirus and extrahepatic biliary atresia in the 10 patients in whom virus RNA was detected.

Reovirus 3 not detected by reverse transcriptase-mediated polymerase chain reaction analysis of preserved tissue from infants with cholestatic liver disease

Reovirus type 3 has been implicated in the origin and pathogenesis of extrahepatic biliary atresia and idiopathic neonatal hepatitis, but routine detection of this virus in hepatobiliary tissues from affected infants by culture and histological techniques has been unsuccessful. In this study, oligonucleotide primers specific to the M3 genome segment of reovirus 3 (Dearing) were used in a reverse transcriptase-mediated polymerase chain reaction technique to develop a sensitive and specific assay for the detection of reovirus 3 RNA in formalin-fixed, paraffin-embedded patient samples. Optimal reaction conditions were determined by testing infected murine tissues and preserved human liver tissue supplemented with reovirus 3. Archival specimens from 50 infants, including 14 with extrahepatic biliary atresia, 20 with idiopathic neonatal hepatitis, and 16 age-matched controls, were evaluated. Successful amplification of human albumin complementary DNA from the preserved tissues confirmed the presence of intact RNA in every patient specimen tested. Analysis of the amplification reactions by agarose gel electrophoresis and Southern blot hybridization detected the presence of reoviral RNA only once in a single patient sample. These results do not support a strong role for reovirus 3 in the development of neonatal cholestatic liver disease. The recent association of other RNA viruses of the Reoviridae family with murine liver disease and human extrahepatic biliary atresia indicates that continued investigation into a viral cause for idiopathic neonatal hepatobiliary disease is warranted.