Mechanism of biliary atresia caused by T follicular helper cells-induced immune injury.

BACKGROUND: Biliary atresia (BA) has diverse and unclear pathogenesis, which may be related to immune response in response to a foreign stimulus. T follicular helper (Tfh) cells have been found to play an important role in various immune diseases. AIMS: To investigate the expression of Tfh cells in BA and non-BA cholestatic diseases in children. METHODS: Transcriptome sequencing and Gene Ontology (GO) enrichment analysis were performed to investigate the differences in gene expression between the BA group and the non-BA cholestasis group. Study the distribution of Tfh cells in liver tissues of the BA and non-BA cholestatic groups through single sample gene set enrichment analysis (ssGSEA). Tfh cells (CD3+Bcl6+) in liver tissues from BA patients were labeled by double immunofluorescent staining to verify their distribution in the liver. RESULTS: Transcriptome sequencing showed differences in gene expression between the BA group and the non-BA cholestasis group. A total of 808 genes were up-regulated and 405 genes were down-regulated in BA, suggesting that there might be a specific immune response in BA. GO enrichment analysis showed that BA group had augmented response to foreign stimulus and increased metabolic process compared to the non-BA cholestatic group. The relative proportion of immune cells was analyzed by ssGSEA method. The proportions of Tfh cells, activated B cells, CD4+ T cells, memory B cells and Th2 cells were higher in the BA group than in the non-BA cholestatic group. Fluorescence immunostaining showed that Tfh cells were significantly increased in liver tissue samples of the BA group compared to the non-BA cholestasis group, which was consistent with the transcriptome sequencing results. CONCLUSION: Tfh cells share in immune cascade involvement in BA. Our work support immune pathogenesis of the in response to a stimulus that might be foreign in BA.

MAPK signaling pathway induced LOX-1+ polymorphonuclear myeloid-derived suppressor cells in biliary atresia.

Biliary atresia (BA) is a severe pediatric liver disease characterized by progressive bile duct destruction and fibrosis, leading to significant liver damage and frequently necessitating liver transplantation. This study elucidates the role of LOX-1+ polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) in BA pathogenesis and assesses their potential as non-invasive early diagnostic biomarkers. Using flow cytometry, immunofluorescence, and molecular profiling, we analyzed the expression and activity of these cells in peripheral blood and liver tissues from BA patients and controls. Our findings reveal a significant increase in the frequencies and function of LOX-1+PMN-MDSCs in BA patients, along with MAPK signaling pathway upregulation, indicating their involvement in disease mechanisms. Additionally, the frequencies of LOX-1+PMN-MDSC in peripheral blood significantly positively correlate with liver function parameters in BA patients, demonstrating diagnostic performance comparable to traditional serum markers. These findings suggest that LOX-1+PMN-MDSCs contribute to the immunosuppressive environment in BA and could serve as potential diagnostic targets.

Polymeric immunoglobulin receptor promotes Th2 immune response in the liver by increasing cholangiocytes derived IL-33: a diagnostic and therapeutic biomarker of biliary atresia.

BACKGROUND: Biliary atresia (BA) is a devastating neonatal cholangiopathy with an unclear pathogenesis, and prompt diagnosis of BA is currently challenging. METHODS: Proteomic and immunoassay analyses were performed with serum samples from 250 patients to find potential BA biomarkers. The expression features of polymeric immunoglobulin receptor (PIGR) were investigated using human biopsy samples, three different experimental mouse models, and cultured human biliary epithelial cells (BECs). Chemically modified small interfering RNA and adenovirus expression vector were applied for in vivo silencing and overexpressing PIGR in a rotavirus-induced BA mouse model. Luminex-based multiplex cytokine assays and RNA sequencing were used to explore the molecular mechanism of PIGR involvement in the BA pathogenesis. FINDINGS: Serum levels of PIGR, poliovirus receptor (PVR), and aldolase B (ALDOB) were increased in BA patients and accurately distinguished BA from infantile hepatitis syndrome (IHS). Combined PIGR and PVR analysis distinguished BA from IHS with an area under the receiver operating characteristic curve of 0.968 and an accuracy of 0.935. PIGR expression was upregulated in the biliary epithelium of BA patients; Th1 cytokines TNF-α and IFN-γ induced PIGR expression in BECs via activating NF-κB pathway. Silencing PIGR alleviated symptoms, reduced IL-33 expression, and restrained hepatic Th2 inflammation in BA mouse model; while overexpressing PIGR increased liver fibrosis and IL-33 expression, and boosted hepatic Th2 inflammation in BA mouse model. PIGR expression promotes the proliferation and epithelial-mesenchymal transition, and reduced the apoptosis of BECs. INTERPRETATION: PIGR participated in BA pathogenesis by promoting hepatic Th2 inflammation via increasing cholangiocytes derived IL-33; PIGR has the value as a diagnostic and therapeutic biomarker of BA. FUNDING: This study was financially supported by the National Natural Science Foundation of China (82170529), the National Key R&D Program (2021YFC2701003), and the National Natural Science Foundation of China (82272022).

Mucosal-associated invariant T cells promote ductular reaction through amphiregulin in biliary atresia.

BACKGROUND: Biliary atresia (BA) is a neonatal fibro-inflammatory cholangiopathy with ductular reaction as a key pathogenic feature predicting poor survival. Mucosal-associated invariant T (MAIT) cells are enriched in human liver and display multiple roles in liver diseases. We aimed to investigate the function of MAIT cells in BA. METHODS: First, we analyzed correlations between liver MAIT cell and clinical parameters (survival, alanine transaminase, bilirubin, histological inflammation and fibrosis) in two public cohorts of patients with BA (US and China). Kaplan-Meier survival analysis and spearman correlation analysis were employed for survival data and other clinical parameters, respectively. Next, we obtained liver samples or peripheral blood from BA and control patients for bulk RNA sequencing, flow cytometry analysis, immunostaning and functional experiments of MAIT cells. Finally, we established two in vitro co-culture systems, one is the rhesus rotavirus (RRV) infected co-culture system to model immune dysfunction of human BA which was validated by single cell RNA sequencing and the other is a multicellular system composed of biliary organoids, LX-2 and MAIT cells to evaluate the role of MAIT cells on ductular reaction. FINDINGS: Liver MAIT cells in BA were positively associated with low survival and ductular reaction. Moreover, liver MAIT cells were activated, exhibited a wound healing signature and highly expressed growth factor Amphiregulin (AREG) in a T cell receptor (TCR)-dependent manner. Antagonism of AREG abrogated the proliferative effect of BA MAIT cells on both cholangiocytes and biliary organoids. A RRV infected co-culture system, recapitulated immune dysfunction of human BA, disclosed that RRV-primed MAIT cells promoted cholangiocyte proliferation via AREG, and further induced inflammation and fibrosis in the multicellular system. INTERPRETATION: MAIT cells exhibit a wound healing signature depending on TCR signaling and promote ductular reaction via AREG, which is associated with advanced fibrosis and predictive of low survival in BA. FUNDING: This work was funded by National Natural Science Foundation of China grant (82001589 and 92168108), National Key R&D Program of China (2023YFA1801600) and by Basic and Applied Basic Research Foundation of Guangdong (2020A1515110921).

Reduced peroxisome proliferator-activated receptor-α and bile acid nuclear receptor NR1H4/FXR may affect the hepatic immune microenvironment of biliary atresia.

Background: Biliary atresia (BA) is a childhood liver disease characterized by fibrous obstruction and obstruction of the extrahepatic biliary system and is one of the most common and serious biliary disorders in infants. Significant inflammation and fibrosis of the liver and biliary tract are the most prominent features, regardless of the initial damage to the BA. Abnormalities in innate or adaptive immunity have been found in human patients and mouse models of BA. We previously reported that children with BA had abnormal lipid metabolism, including free serum carnitine. Objective: To study gene and protein expression levels of the hepatic peroxisome proliferator-activated receptor-α (PPARα) signaling pathway and farnesoid X receptor (FXR) in BA and BA fibrosis, and assess their clinical values. Methods: Low expression of PPARα and NR1H4 (FXR) in BA were validated in the Gene Expression Omnibus database. Functional differences were determined by gene set enrichment analysis based on of PPARα and NR1H4 expression. BA patients from GSE46960 were divided into two clusters by using consensus clustering according to PPARα, NR1H4, and SMAD3 expression levels, and immunoinfiltration analysis was performed. Finally, 58 cases treated in our hospital were used for experimental verification. (IHC: 10 Biliary atresia, 10 choledochal cysts; PCR: 10 Biliary atresia, 14 choledochal cysts; WB: 10 Biliary atresia, 4 choledochal cysts). Results: Bioinformatics analysis showed that the expression of PPARα, CYP7A1 and NR1H4 (FXR) in the biliary atresia group was significantly lower than in the control group. More BA-specific pathways, including TGFß signaling pathway, P53 signaling pathway, PI3K-AKT-mTOR signaling pathway, etc., are enriched in BA patients with low PPARα and NR1H4 expression. In addition, low NR1H4 expression is abundant in inflammatory responses, IL6/STAT3 signaling pathways, early estrogen responses, IL2 STAT5 signaling pathways, and TGFß signaling pathways. The TGFß signaling pathway was significant in both groups. According to the expression of PPARα, NR1H4 and SMAD3, a key node in TGFß pathway, BA patients were divided into two clusters using consensus clustering. In cluster 2, SMAD3 expression was high, and PPARα and NR1H4 expression were low. In contrast to cluster 1, immune cell infiltration was higher in cluster 2, which was confirmed by immunohistochemistry. The mRNA and protein levels of PPARα and NR1H4 in BA patients were lower than in the control group by immunohistochemistry, Western blot analysis and real-time PCR. Conclusions: The downregulation of PPARα and NR1H4 (FXR) signaling pathway may be closely related to biliary atresia.

Maternal regulation of biliary disease in neonates via gut microbial metabolites.

Maternal seeding of the microbiome in neonates promotes a long-lasting biological footprint, but how it impacts disease susceptibility in early life remains unknown. We hypothesized that feeding butyrate to pregnant mice influences the newborn's susceptibility to biliary atresia, a severe cholangiopathy of neonates. Here, we show that butyrate administration to mothers renders newborn mice resistant to inflammation and injury of bile ducts and improves survival. The prevention of hepatic immune cell activation and survival trait is linked to fecal signatures of Bacteroidetes and Clostridia and increases glutamate/glutamine and hypoxanthine in stool metabolites of newborn mice. In human neonates with biliary atresia, the fecal microbiome signature of these bacteria is under-represented, with suppression of glutamate/glutamine and increased hypoxanthine pathways. The direct administration of butyrate or glutamine to newborn mice attenuates the disease phenotype, but only glutamine renders bile duct epithelial cells resistant to cytotoxicity by natural killer cells. Thus, maternal intake of butyrate influences the fecal microbial population and metabolites in newborn mice and the phenotypic expression of experimental biliary atresia, with glutamine promoting survival of bile duct epithelial cells.

Unique Cholangiocyte-Targeted IgM Autoantibodies Correlate With Poor Outcome in Biliary Atresia.

BACKGROUND AND AIMS: The etiology of biliary atresia (BA) is not known and is likely multifactorial, including a genetic predisposition, a viral or environmental trigger, an aberrant autoimmune response targeting cholangiocytes, and unique susceptibilities of the neonatal bile ducts to injury. Damaged cholangiocytes may express neo self-antigens and elicit autoreactive T-cell-mediated inflammation and B-cell production of autoantibodies. The aim of this study was to discover autoantibodies in BA that correlated with outcomes. APPROACH AND RESULTS: An autoantigen microarray encompassing approximately 9,500 autoantigens was used to screen for serum immunoglobulin M (IgM) and immunoglobulin G (IgG) autoantibodies in patients with BA or other liver disease controls. Validation of candidate autoantibodies by enzyme-linked immunosorbent assay on a second cohort of subjects (6-12 months following Kasai portoenterostomy) and correlations of autoantibodies with outcomes were performed (serum bilirubin levels and need for liver transplant in first 2 years of life). Mean anti-chitinase 3-like 1 (CHI3L1), anti-delta-like ligand (DLL-4), and antisurfactant protein D (SFTPD) IgM autoantibodies in BA were significantly higher compared with controls, and IgM autoantibody levels positively correlated with worse outcomes. Immunofluorescence revealed cholangiocyte-predominant expression of CHI3L1, DLL-4, and SFTPD. The humoral autoantibody response was associated with C3d complement activation and T-cell autoimmunity, based on detection of cholangiocyte-predominant C3d co-staining and peripheral blood autoreactive T cells specific to CHI3L1, DLL-4 and SFTPD, respectively. CONCLUSIONS: BA is associated with cholangiocyte-predominant IgM autoantibodies in the first year after Kasai portoenterostomy. Anti-CHI3L1, anti-DLL-4, and anti-SFTPD IgM autoantibody correlations with worse outcomes and the detection of C3d on cholangioctyes and antigen-specific autoreactive T cells suggest that autoimmunity plays a role in the ongoing bile duct injury and progression of disease.

Liver Immune Profiling Reveals Pathogenesis and Therapeutics for Biliary Atresia.

Biliary atresia (BA) is a severe cholangiopathy that leads to liver failure in infants, but its pathogenesis remains to be fully characterized. By single-cell RNA profiling, we observed macrophage hypo-inflammation, Kupffer cell scavenger function defects, cytotoxic T cell expansion, and deficiency of CX3CR1+effector T and natural killer (NK) cells in infants with BA. More importantly, we discovered that hepatic B cell lymphopoiesis did not cease after birth and that tolerance defects contributed to immunoglobulin G (IgG)-autoantibody accumulation in BA. In a rhesus-rotavirus induced BA model, depleting B cells or blocking antigen presentation ameliorated liver damage. In a pilot clinical study, we demonstrated that rituximab was effective in depleting hepatic B cells and restoring the functions of macrophages, Kupffer cells, and T cells to levels comparable to those of control subjects. In summary, our comprehensive immune profiling in infants with BA had educed that B-cell-modifying therapies may alleviate liver pathology.

Inflammation Drives MicroRNAs to Limit Hepatocyte Bile Acid Transport in Murine Biliary Atresia.

BACKGROUND: Biliary atresia (BA) is an inflammatory pediatric cholangiopathy with only surgical means for treatment. Many contributors to bile acid synthesis and transport have previously been reported to be downregulated in patients with BA; yet, the driving factors of the abnormal bile acid synthesis and transport in regard to BA have not been previously studied. MATERIALS AND METHODS: Wild type or Ig-α-/- mice were injected with salt solution (control) or rotavirus on day of life 0, and analyses were performed on day of life 14. The mRNA levels of bile acid transporters/nuclear receptors and liver microRNAs (miRNAs) were compared between groups. A mouse hepatocyte cell line was used to examine the effects of innate cytokines on miRNA levels and bile acid transporter/nuclear receptor expression and miRNAs on bile acid transporter/nuclear receptor expression. RESULTS: BA mice had significantly increased mRNA expression of innate cytokines and miRNAs known to bind bile acid transporters/nuclear receptors (miRNAs -22-5p, -34a-5p, and -222-3p) and decreased mRNA expression of bile acid transporters and nuclear receptors. In vitro, TNF-α and IL-1ß decreased BSEP and CYP7A1 while increasing miRNA-34a-5p and miRNA 222-3p. LXR, SHP, CYP7A1, NTCP, and MRP2 were decreased by miRNA-34a-5p, whereas miRNA-222-3p decreased NTCP and MRP4. TNF-α and IL-1ß increased expression of miRNAs 34a-5p and 222-3p and these miRNAs then decrease expression of multiple bile acid transporters and nuclear receptors. CONCLUSIONS: Loss of bile acid transporters increases hepatotoxicity via bile acid retention. Therapeutic agents that increase bile acid transport or nuclear receptor functioning should be investigated in BA.

CXCL8high inflammatory B cells in the peripheral blood of patients with biliary atresia are involved in disease progression.

Biliary atresia (BA), the most common cause of pediatric end-stage liver disease, results from fibroinflammatory obstruction of the intrahepatic and extrahepatic bile ducts. The etiology of BA has been extensively studied, and inflammation and imbalanced immune system have been identified as the main pathogenesis of BA. B cells play roles in innate and adaptive immunity, but few studies have investigated the role of B cells in BA. This study aimed to elucidate the role of B cells in the development of BA. The percentage and numbers of total B cells (23.81 ± 11.14%，P < 0.0001, 1.22 ± 0.67 × 109 L-1 , P = 0.0014) and immature B cells (25.33 ± 14.32%, P = 0.0013, 0.19 ± 0.20 × 109 L-1 , P < 0.0001) were significantly increased in the peripheral blood of patients with BA and the number of total B cells was positively correlated with gamma-glutamyl-transpeptidase in the serum of BA. High C-X-C motif chemokine ligand 8 (CXCL8) levels were detected in the serum of patients with BA. As an important source of CXCL8, B cells from patients with BA secreted more CXCL8 into peripheral blood than those from control patients. Moreover, immature B cells can secrete more CXCL8 than mature B cells, and B cells secreted CXCL8 upon activation of the nuclear factor-κB pathway. Taken together, the results revealed that B cells have a strong ability to secrete CXCL8, which is associated with the pathogenesis of BA, and exert a proinflammatory effect on the development of BA.

Innate Immunity and Pathogenesis of Biliary Atresia.

Biliary atresia (BA) is a devastating fibro-inflammatory disease characterized by the obstruction of extrahepatic and intrahepatic bile ducts in infants that can have fatal consequences, when not treated in a timely manner. It is the most common indication of pediatric liver transplantation worldwide and the development of new therapies, to alleviate the need of surgical intervention, has been hindered due to its complexity and lack of understanding of the disease pathogenesis. For that reason, significant efforts have been made toward the development of experimental models and strategies to understand the etiology and disease mechanisms and to identify novel therapeutic targets. The only characterized model of BA, using a Rhesus Rotavirus Type A infection of newborn BALB/c mice, has enabled the identification of key cellular and molecular targets involved in epithelial injury and duct obstruction. However, the establishment of an unleashed chronic inflammation followed by a progressive pathological wound healing process remains poorly understood. Like T cells, macrophages can adopt different functional programs [pro-inflammatory (M1) and resolutive (M2) macrophages] and influence the surrounding cytokine environment and the cell response to injury. In this review, we provide an overview of the immunopathogenesis of BA, discuss the implication of innate immunity in the disease pathogenesis and highlight their suitability as therapeutic targets.

The Contribution of B Cells in Autoimmune Liver Diseases.

Autoreactive B cells can promote autoimmunity through antigen presentation to autoreactive T cells, production of autoantibodies, generation of cytokines promoting T cell activation and differentiation, and inhibition of regulatory T cells and B cells. Here, the authors highlight studies pertaining to B cell mechanisms associated with disease pathogenesis and outcomes in autoimmune hepatitis and the immune-mediated cholangiopathies (primary biliary cholangitis, primary sclerosing cholangitis, and biliary atresia). The vast majority of investigations focus on autoantibodies and future research endeavors should include deciphering the role of the B cell in T cell activation (through antigen presentation, cytokine/chemokine production, and inhibition of regulation). Targeting B cell mechanisms in the treatment of autoimmune liver diseases is also highlighted.

Oligoclonal immunoglobulin repertoire in biliary remnants of biliary atresia.

Biliary atresia (BA) is a neonatal cholestatic liver disease that is the leading cause of pediatric liver transplantation, however, the mechanism of disease remains unknown. There are two major forms of BA: isolated BA (iBA) comprises the majority of cases and is thought to result from an aberrant immune response to an environmental trigger, whereas syndromic BA (BASM) has associated malformations and is thought to arise from a congenital insult. To determine whether B cells in BA biliary remnants are antigen driven, we examined the immunoglobulin (Ig) repertoire of diseased tissue from each BA group. Deep sequencing of the Ig chain DNA was performed on iBA and BASM biliary remnants and lymph nodes obtained from the Childhood Liver Disease Research Network (ChiLDReN) repository. Statistical analysis of the Ig repertoire provided measures of Ig clonality and the Ig phenotype. Our data demonstrate that B cells infiltrate diseased iBA and BASM biliary remnant tissue. The Ig repertoires of iBA and BASM disease groups were oligoclonal supporting a role for an antigen-driven immune response in both sub-types. These findings shift the current understanding of BA and suggest a role for antigen stimulation in early iBA and BASM disease pathogenesis.

Th17-associated cytokines multiplex testing indicates the potential of macrophage inflammatory protein-3 alpha in the diagnosis of biliary atresia.

BACKGROUND & AIMS: Biliary atresia (BA) is a neonatal obliterative cholangiopathy with high prevalence in south China. Accurate identification of BA among infants with obstructive jaundice is still difficult by noninvasive diagnostic tools. Th17 cells have been reported closely related with the development of BA, which suggest that Th17-associated cytokines were potential biomarkers for the diagnosis of BA patients. METHODS: In the training study, 76 infants who were divided into 2 groups, including BA group (n = 31) and non-BA jaundice group (n = 45). Clinical and routine laboratory data were collected from all subjects. Totally 25 Th17-associated cytokines were tested and compared between groups. The diagnostic value of each differential cytokine was evaluated by the area under the receiver operating characteristic curve (AUC). The best potential diagnostic biomarker was further validated in a cohort including 68 jaundice infants from our partnering institution in a blinded fashion. RESULTS: Data from the training study showed that gamma-glutamyl transferase (GGT) and clay stool would be helpful in the identification of BA patients in jaundice subjects. Th17-associated cytokines assay indicated that IL-17F, IL-10, macrophage inflammatory protein-3alpha (MIP3a), IL-22, IL-13, IL-33, IL-6, IL-17E, IL-27, IL-31, TNF-a and TNF-b were differentially expressed in BA patients, and the AUC of MIP3a was higher than other markers. MIP3a alone or combined with other laboratory data would significantly increase the diagnostic accuracy of BA. The diagnostic value of MIP3a was further confirmed in our validation study. CONCLUSION: MIP3a alone or combined with other laboratory data would significantly increase the diagnostic accuracy of BA.

Periductal Lymphocytic Infiltrate at Bilary Atresia Diagnosis Increases the Risk of Addition to the Transplant Waitlist.

PURPOSE: Biliary atresia (BA) is the main indication for pediatric liver transplantation. The aim of this study is to correlate aspects of histological examinations of diagnostic hepatic biopsies for BA with the patients' clinical progression and successful addition to the liver transplant waitlist. METHODS: This was a retrospective study of all 108 BA cases treated at the Federal University of São Paulo (1998-2015). Demographic and clinical data were correlated with histological findings. A logistic regression was used for outcome analysis, while the Kaplan-Meier method was applied for survival analysis. RESULTS: There were 108 patients with BA, 68.5% of whom underwent Kasai surgery. Patients added to the transplant waitlist tended to undergo Kasai surgery at a later time (P = .035). Periductal lymphocytic infiltrate was correlated with the addition to the transplant waitlist, with an odds ratio of 3.92 (P = .033). Patients who developed ascites after surgery were more frequently added to the transplant waitlist (P = .05). CONCLUSION: Patients added to the transplant waitlist underwent Kasai surgery later than other patients. Periductal lymphocytic infiltrate in the diagnostic hepatic biopsy and ascites after Kasai surgery were associated with an increased likelihood of addition to the transplant waitlist.

Cytokine-Producing B Cells Promote Immune-Mediated Bile Duct Injury in Murine Biliary Atresia.

Biliary atresia (BA) is a neonatal T cell-mediated, inflammatory, sclerosing cholangiopathy. In the rhesus rotavirus (RRV)-induced neonatal mouse model of BA (murine BA), mice lacking B cells do not develop BA, and the lack of B cells is associated with loss of T-cell and macrophage activation. The aim of this study was to determine the mechanism of B cell-mediated immune activation (antigen presentation versus cytokine production) in murine BA. Normal neonatal B cells in the liver are predominantly at pro-B and pre-B cellular development. However, BA mice exhibit a significant increase in the number and activation status of mature liver B cells. Adoptively transferred B cells into RRV-infected, B cell-deficient mice were able to reinstate T-cell and macrophage infiltration and biliary injury. Nonetheless, neonatal liver B cells were incompetent at antigen presentation to T cells. Moreover, 3-83 immunoglobulin transgenic mice, in which B cells only present an irrelevant antigen, developed BA, indicating a B-cell antigen-independent mechanism. B cells from BA mice produced a variety of innate and adaptive immune cytokines associated with immune activation. In vitro trans-well studies revealed that BA B cells secreted cytokines that activated T cells based on increased expression of T-cell activation marker cluster of differentiation 69. Conclusion: Neonatal liver B cells are highly activated in murine BA and contribute to immune activation through production of numerous cytokines involved in innate and adaptive immunity; this work provides increased knowledge on the capacity of neonatal B cells to contribute to an inflammatory disease through cytokine-mediated mechanisms, and future studies should focus on targeting B cells as a therapeutic intervention in human BA.

Autoimmune liver disease-related autoantibodies in patients with biliary atresia.

AIM: To investigate the prevalence and clinical significance of autoimmune liver disease (ALD)-related autoantibodies in patients with biliary atresia (BA). METHODS: Sera of 124 BA patients and 140 age-matched non-BA controls were assayed for detection of the following autoantibodies: ALD profile and specific anti-nuclear antibodies (ANAs), by line-blot assay; ANA and anti-neutrophil cytoplasmic antibody (ANCA), by indirect immunofluorescence assay; specific ANCAs and anti-M2-3E, by enzyme linked immunosorbent assay. Associations of these autoantibodies with the clinical features of BA (i.e., cytomegalovirus infection, degree of liver fibrosis, and short-term prognosis of Kasai procedure) were evaluated by Spearman's correlation coefficient. RESULTS: The overall positive rate of serum autoantibodies in preoperative BA patients was 56.5%. ALD profile assay showed that the positive reaction to primary biliary cholangitis-related autoantibodies in BA patients was higher than that to autoimmune hepatitis-related autoantibodies. Among these autoantibodies, anti-BPO was detected more frequently in the BA patients than in the controls (14.8% vs 2.2%, P < 0.05). Accordingly, 32 (25.8%) of the 124 BA patients also showed a high positive reaction for anti-M2-3E. By comparison, the controls had a remarkably lower frequency of anti-M2-3E (P < 0.05), with 6/92 (8.6%) of patients with other liver diseases and 2/48 (4.2%) of healthy controls. The prevalence of ANA in BA patients was 11.3%, which was higher than that in disease controls (3.3%, P < 0.05), but the reactivity to specific ANAs was only 8.2%. The prevalence of ANCAs (ANCA or specific ANCAs) in BA patients was also remarkably higher than that in the healthy controls (37.9% vs 6.3%, P < 0.05), but showed no difference from that in patients with other cholestasis. ANCA positivity was closely associated with the occurrence of postoperative cholangitis (r = 0.61, P < 0.05), whereas none of the autoantibodies showed a correlation to cytomegalovirus infection or the stages of liver fibrosis. CONCLUSION: High prevalence of autoantibodies in the BA developmental process strongly reveals the autoimmune-mediated pathogenesis. Serological ANCA positivity may be a useful predictive biomarker of postoperative cholangitis.

Unique manifestations of biliary atresia provide new immunological insight into its etiopathogenesis.

Biliary atresia (BA) is a unique cholestatic disease of newborns with a background of exaggerated immune response in the liver of unknown mechanism. Three hypotheses have been proposed; autoimmune type of cholangiopathy triggered by virus infection, graft-versus-host disease type of immune-mediated disease associated with maternal microchimerism and ductal plate malformation theory. Researchers on virus infection theory have experimentally explored immune process causing cholangiopathy on murine models of this disease, while in maternal microchimerism hypothesis were detected maternal cells in the BA patients' liver, of which roles are yet to be determined. Ductal plate malformation theory is an intriguing hypothesis in the sense that it suggests the onset of this disease is in the first trimester. This theory can be secondary to either one of these two immune-related insults. In this review, four unique points are focused; (1) the timing of onset, (2) hepatitis-like pathological picture, (3) heterogenous atrophy of the liver segments when advanced, and (4) swollen lymph nodes at the porta hepatis. These unique clinicopahtological aspects of this disease should be well explained by these hypotheses.

Update on investigations pertaining to the pathogenesis of biliary atresia.

Biliary atresia is a devastating biliary disease of neonates that results in liver transplantation for the vast majority. The etiology of biliary atresia is unknown and is likely multifactorial, with components of genetic predisposition, environmental trigger and autoimmunity contributing to disease pathogenesis. This review highlights recent work related to investigations of disease pathogenesis in biliary atresia.