The immunobiology and pathophysiology of primary biliary cirrhosis

Progress in treatment of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic autoimmune cholestatic liver disease characterized by cholestasis, and it often eventually develops into cirrhosis, portal hypertension and liver failure. Asymptomatic patients typically are diagnosed by the elevation of alkaline phosphatase (ALP) and the presence of anti-mitochondrial antibody (AMA) titers of 1:40 or greater. Ursodeoxycholic acid (UDCA) is the only Food and Drug Administration approved treatment for PBC, but it is not universally effective. In patients with UDCA-refractory PBC, additional therapies should be considered, including budesonide, fibrates, obeticholic acid, immunosuppressants and liver transplantation.

Post-translational regulation of the type III inositol 1,4,5-trisphosphate receptor by miRNA-506

The type III isoform of the inositol 1,4,5-trisphosphate receptor (InsP3R3) is apically localized and triggers Ca(2+) waves and secretion in a number of polarized epithelia. However, nothing is known about epigenetic regulation of this InsP3R isoform. We investigated miRNA regulation of InsP3R3 in primary bile duct epithelia (cholangiocytes) and in the H69 cholangiocyte cell line, because the role of InsP3R3 in cholangiocyte Ca(2+) signaling and secretion is well established and because loss of InsP3R3 from cholangiocytes is responsible for the impairment in bile secretion that occurs in a number of liver diseases. Analysis of the 3'-UTR of human InsP3R3 mRNA revealed two highly conserved binding sites for miR-506. Transfection of miR-506 mimics into cell lines expressing InsP3R3-3'UTR-luciferase led to decreased reporter activity, whereas co-transfection with miR-506 inhibitors led to enhanced activity. Reporter activity was abrogated in isolated mutant proximal or distal miR-506 constructs in miR-506-transfected HEK293 cells. InsP3R3 protein levels were decreased by miR-506 mimics and increased by inhibitors, and InsP3R3 expression was markedly decreased in H69 cells stably transfected with miR-506 relative to control cells. miR-506-H69 cells exhibited a fibrotic signature. In situ hybridization revealed elevated miR-506 expression in vivo in human-diseased cholangiocytes. Histamine-induced, InsP3-mediated Ca(2+) signals were decreased by 50% in stable miR-506 cells compared with controls. Finally, InsP3R3-mediated fluid secretion was significantly decreased in isolated bile duct units transfected with miR-506, relative to control IBDU. Together, these data identify miR-506 as a regulator of InsP3R3 expression and InsP3R3-mediated Ca(2+) signaling and secretion.

Noninvasive markers in the assessment and management of autoimmune liver diseases

Historically, liver biopsy has been used to determine the etiology of liver disease, the degree of inflammation, the stage of liver fibrosis, and the response to treatments. In the last decade, the advent of noninvasive tests has improved the diagnosis and management of autoimmune liver diseases. For example, serum markers can identify hepatic inflammation, whereas ultrasound and MRI can diagnose liver fibrosis. Physicians now have a much larger repertoire of diagnostic tests to assess the liver parenchyma compared with liver biopsy alone. In some rare cases, noninvasive tests may provide an alternative to liver biopsy. In general, however, these noninvasive tests complement liver biopsy and provide quick, accurate, and reliable adjunctive data.

Mouse models of liver fibrosis mimic human liver fibrosis of different etiologies

The liver has the amazing capacity to repair itself after injury; however, the same processes that are involved in liver regeneration after acute injury can cause serious consequences during chronic liver injury. In an effort to repair damage, activated hepatic stellate cells trigger a cascade of events that lead to deposition and accumulation of extracellular matrix components causing the progressive replacement of the liver parenchyma by scar tissue, thus resulting in fibrosis. Although fibrosis occurs as a result of many chronic liver diseases, the molecular mechanisms involved depend on the underlying etiology. Since studying liver fibrosis in human subjects is complicated by many factors, mouse models of liver fibrosis that mimic the human conditions fill this void. This review summarizes the general mouse models of liver fibrosis and mouse models that mimic specific human disease conditions that result in liver fibrosis. Additionally, recent progress that has been made in understanding the molecular mechanisms involved in the fibrogenic processes of each of the human disease conditions is highlighted.

Genetics of autoimmune liver disease: a brief summary for clinicians

Autoimmune liver diseases are rare chronic immune-mediated liver injuries in which the consequences of hepatic and biliary inflammation are cirrhosis and end-stage liver disease. Epidemiological surveys of individuals, families and populations strongly support a model of disease for which environmental and genetic influences are highly relevant to why any individual develops disease. The overlapping clinical presentations of primary biliary cirrhosis, primary sclerosing cholangitis and autoimmune hepatitis further highlight the likelihood for shared pathways to disease. Of late, the application of high-throughput genetic technology, paralleled by large patient cohort development, has led to new insights into the nature of the host genetic risk. This risk is now robustly demonstrable for the HLA locus as well as in various non-HLA loci and is summarized in this brief review article.

Differential modulation by IL-17A of Cholangitis versus Colitis in IL-2Rα deleted mice

IFN-γ is a signature Th1 cell associated cytokine critical for the inflammatory response in autoimmunity with both pro-inflammatory and potentially protective functions. IL-17A is the hallmark of T helper 17 (Th17) cell subsets, produced by γδT, CD8+ T, NK and NKT cells. We have taken advantage of our colony of IL-2Rα-/- mice that spontaneously develop both autoimmune cholangitis and inflammatory bowel disease. In this model CD8+ T cells mediate biliary ductular damage, whereas CD4+ T cells mediate induction of colon-specific autoimmunity. Importantly, IL-2Rα-/- mice have high levels of interferon γ (IFN-γ), and interleukin-17A (IL-17A). We produced unique double deletions of mice that were either IL-17A-/-IL-2Rα-/- or IFN-γ-/-IL-2Rα-/- to specifically address the precise role of these two cytokines in the natural history of autoimmune cholangitis and colitis. Of note, deletion of IL-17A in IL-2Rα-/- mice led to more severe liver inflammation, but ameliorated colitis. In contrast, there were no significant changes in the immunopathology of double knock-out IFN-γ-/- IL-2Rα-/- mice, compared to single knock-out IL-2Rα-/- mice with respect to cholangitis or colitis. Furthermore, there was a significant increase in pathogenetic CD8+ T cells in the liver of IL-17A-/-IL-2Rα-/- mice. Our data suggest that while IL-17A plays a protective role in autoimmune cholangitis, it has a pro-inflammatory role in inflammatory bowel disease. These data take on particular significance in the potential use of anti-IL-17A therapy in humans with primary biliary cirrhosis.

Mechanisms of tissue injury in autoimmune liver diseases

Autoimmune diseases affecting the liver are mainly represented by autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). The characteristic morphologic patterns of injury are a chronic hepatitis pattern of damage in AIH, destruction of small intrahepatic bile ducts in PBC and periductal fibrosis and inflammation involving larger bile ducts in PSC. The factors responsible for initiation and perpetuation of the injury in all the three autoimmune liver diseases are not understood completely but are likely to be environmental triggers on the background of genetic variation in immune regulation. In this review, we summarise the current understanding of the mechanisms underlying the breakdown of self-tolerance in autoimmune liver diseases.

Environmental factors in primary biliary cirrhosis

The etiology of the autoimmune liver disease primary biliary cirrhosis (PBC) remains largely unresolved, owing in large part to the complexity of interaction between environmental and genetic contributors underlying disease development. Observations of disease clustering, differences in geographical prevalence, and seasonality of diagnosis rates suggest the environmental component to PBC is strong, and epidemiological studies have consistently found cigarette smoking and history of urinary tract infection to be associated with PBC. Current evidence implicates molecular mimicry as a primary mechanism driving loss of tolerance and subsequent autoimmunity in PBC, yet other environmentally influenced disease processes are likely to be involved in pathogenesis. In this review, the authors provide an overview of current findings and touch on potential mechanisms behind the environmental component of PBC.

Therapeutic role of bile acids and nuclear receptor agonists in fibrosing cholangiopathies

Chronic inflammatory bile duct diseases such as primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) result in progressive fibrosis of the biliary tract and ultimately cirrhosis of the liver. Since the etiology and pathogenesis of these fibrosing cholangiopathies are still poorly understood, therapeutic options are rather limited at present. Ursodeoxycholic acid (UDCA) is the paradigm therapeutic bile acid and established standard treatment for PBC, but its role for medical therapy of PSC is still under debate. Promising novel bile acid-based therapeutic options include 24-norursodeoxycholic acid, a side chain-shortened C23 homologue of UDCA, and bile acid receptor/farnesoid X receptor agonists (e.g., obeticholic acid) which currently undergo clinical development for fibrosing cholangiopathies such as PBC and PSC. Other nuclear receptors such as vitamin D receptor and fatty acid-activated peroxisome proliferator-activated receptors are also of considerable interest. This review article is a summary of an overview talk given at Falk Symposium 191 on Advances in Pathogenesis and Treatment of Liver Diseases held in London, October 3-4, 2013, and summarizes the recent progress with novel therapeutic bile acids and bile acid derivatives as novel therapies for fibrosing cholangiopathies such as PBC and PSC.

Immunological basis of stem cell therapy in liver diseases

Unbalanced immune cell populations or immune cell infiltration of the liver can disrupt the immune-privileged state of the liver, resulting in liver injury or fibrosis. Therefore, the treatment for liver diseases involves not only hepatic regeneration but also immunological regulation. Recent studies demonstrated that stem cells, especially mesenchymal stem cells, have the capacity for not only hepatic differentiation but also immunomodulation. In this respect, stem cell therapy could be a realistic aim for liver diseases by modulating the liver regenerative processes and down-regulating immune-mediated liver damage. In this review, we discuss in detail the importance of immune cells in liver injury and repair; the mechanism by which stem cells demonstrate an immune-tolerant phenotype that can be used for allogeneic transplantation; the effect of stem cell transplantation on immune-mediated diseases, especially liver diseases; and the mechanism by which stem cells improve the hepatic microenvironment.

Optimising risk stratification in primary biliary cirrhosis: AST/platelet ratio index predicts outcome independent of ursodeoxycholic acid response

BACKGROUND & AIMS

Outcomes in primary biliary cirrhosis (PBC) can be predicted by biochemical response to ursodeoxycholic acid (UDCA). Such stratification inadequately captures cirrhosis/portal hypertension, recognised factors associated with adverse events.

METHODS

We evaluated a cohort of PBC patients (n=386) attending the Liver Unit in Birmingham (derivation cohort), seeking to identify risk-variables associated with transplant-free survival independent of UDCA-response. A validation cohort was provided through well-characterised patients attending the Toronto Center for Liver Diseases (n=479) and Jena University Hospital (n=150).

RESULTS

On multivariate analysis, factors at diagnosis associated with liver transplant (LT)/death were patient age (HR:1.06; p<0.001), elevated bilirubin (HR:1.27; p<0.001), early-onset cirrhosis (HR:2.40; p<0.001) and baseline AST/platelet ratio index (APRI) (HR:1.95; p<0.001). At 1-year, UDCA biochemical non-response predicted poorer transplant-free survival, and additional factors (multivariate) associated with adverse outcome were age (HR:1.02; p<0.05) and 1-year APRI (HR:1.15; p<0.001). Obtaining a cut-point from our derivation cohort, APRI >0.54 at baseline was predictive of LT/death (adjusted HR: 2.40; p<0.001), and retained statistical significance when applied at 1-year (APRI-r1, adjusted HR:2.75; p<0.001) despite controlling for UDCA-response. Across both cohorts, transplant-free survival was poorer for biochemical-responders with an APRI-r1 >0.54 vs. biochemical-responders with a lower APRI-r1 (p<0.01 and p<0.001, respectively); non-responders with high APRI-r1 had the poorest outcomes (p<0.001 and p<0.001).

CONCLUSION

In PBC, elevated APRI is associated with future risk of adverse events, independently and additively of UDCA-response. This cross-centre, robustly validated observation will contribute to ongoing efforts to refine existing risk-stratification tools, as well as direct focus for new therapies in patients with PBC.

The sodium leak channel, NALCN, in health and disease

Ion channels are crucial components of cellular excitability and are involved in many neurological diseases. This review focuses on the sodium leak, G protein-coupled receptors (GPCRs)-activated NALCN channel that is predominantly expressed in neurons where it regulates the resting membrane potential and neuronal excitability. NALCN is part of a complex that includes not only GPCRs, but also UNC-79, UNC-80, NLF-1 and src family of Tyrosine kinases (SFKs). There is growing evidence that the NALCN channelosome critically regulates its ion conduction. Both in mammals and invertebrates, animal models revealed an involvement in many processes such as locomotor behaviors, sensitivity to volatile anesthetics, and respiratory rhythms. There is also evidence that alteration in this NALCN channelosome can cause a wide variety of diseases. Indeed, mutations in the NALCN gene were identified in Infantile Neuroaxonal Dystrophy (INAD) patients, as well as in patients with an Autosomal Recessive Syndrome with severe hypotonia, speech impairment, and cognitive delay. Deletions in NALCN gene were also reported in diseases such as 13q syndrome. In addition, genes encoding NALCN, NLF- 1, UNC-79, and UNC-80 proteins may be susceptibility loci for several diseases including bipolar disorder, schizophrenia, Alzheimer's disease, autism, epilepsy, alcoholism, cardiac diseases and cancer. Although the physiological role of the NALCN channelosome is poorly understood, its involvement in human diseases should foster interest for drug development in the near future. Toward this goal, we review here the current knowledge on the NALCN channelosome in physiology and diseases.

Reduced FOXP3(+) regulatory T cells in patients with primary sclerosing cholangitis are associated with IL2RA gene polymorphisms

BACKGROUND & AIMS

Recently, genome wide association studies in primary sclerosing cholangitis (PSC) revealed associations with gene polymorphisms that potentially could affect the function of regulatory T cells (Treg). The aim of this study was to investigate Treg in patients with PSC and to associate their numbers with relevant gene polymorphisms.

METHODS

Treg frequency in blood was assessed by staining for CD4(+)CD25(high)FOXP3(+)CD127(low) lymphocytes and determination of Treg-specific FOXP3 gene locus demethylation. Single nucleotide polymorphisms (SNP) in the interleukin-2 receptor alpha (IL2RA), the interleukin-2 (IL2) and interleukin-21 (IL21) gene locus were analysed. Liver biopsies taken at the time of diagnosis were stained for FOXP3 and CD3. Treg function was assessed in a CFSE-based suppression assay.

RESULTS

The frequency of Treg in peripheral blood of PSC patients was significantly decreased. We confirmed this finding by demonstrating a reduction of non-methylated DNA in the Treg-specific demethylated FOXP3 gene region of peripheral blood cells in PSC patients. Reduced peripheral Treg numbers were significantly associated with homozygosity for the major allele of the SNP "rs10905718" in the IL2RA gene. Intrahepatic FOXP3(+) cell numbers at the time of initial diagnosis were decreased in PSC as compared to PBC. In addition to reduced numbers, the suppressive capacity of Treg isolated from PSC patients seemed to be impaired as compared to healthy controls.

CONCLUSIONS

Our findings indicate that Treg impairment may play a role in the immune dysregulation observed in PSC. Reduced Treg numbers in patients with PSC are associated with polymorphisms in the IL2RA gene.

Primary biliary cirrhosis in 2014

PURPOSE OF REVIEW

Primary biliary cirrhosis (PBC) was first described in the 1950s as a clinical syndrome of progressive cholestatic liver disease resulting from chronic inflammatory destruction of the intrahepatic bile ducts. In the 1980s, the autoimmune nature of the disease was appreciated with the discovery of disease-specific loss of immune tolerance to the pyruvate dehydrogenase complex and subsequent development of antimitochondrial antibodies and autoreactive T cells. Then, in the 1990s, multiple clinical trials demonstrating the efficacy of ursodiol as a treatment for PBC were published, although it has been clear that ursodiol is not a cure and only delays progression in some patients.

RECENT FINDINGS

The study of PBC in the 2000s has been buoyed by two basic science advances: rapid sequencing technologies that have led to genome wide association studies, and elucidation of the role of nuclear hormone receptors in the regulation of bile salt metabolism, which has led to novel therapies under study for cholestatic diseases.

SUMMARY

Today's clinician should be able to determine which patients with PBC are likely to progress despite treatment with ursodiol and understand the putative new bile acid and immunosuppressant treatment strategies under development, as well as be aware of the recently described genetic factors at play in the development of PBC.

Pathophysiology and recent findings of primary biliary cirrhosis complicated by systemic sclerosis

Primary biliary cirrhosis (PBC) can be complicated by systemic sclerosis (SSc) and, more specifically, limited cutaneous SSc (lcSSc), which was previously called CREST syndrome. Moreover, combined PBC and SSc has been described in many case reports. Although neither the etiology of PBC nor that of SSc has been elucidated, some genetic and immunological factors are known to be shared. Both disorders are autoimmune fibrotic diseases characterized by increased levels of profibrotic cytokines transforming growth factor β (TGFβ) and interleukin-6, which have recently been suggested to influence T-helper 17 cells and regulatory T cells involved in acquired immunity. lcSSc is accompanied by CREST symptoms, although complete CREST cases are rare, with relatively high prevalence of Raynaud's phenomenon, sclerodactyly and telangiectasia, and lower prevalence of calcinosis and esophageal dysmotility. Because patients with anticentromere antibody positive PBC-SSc are at a high risk of developing portal hypertension, particular attention should be paid to the management of gastroesophageal varices. In addition, the management of SSc-related non-hepatic disorders, such as pulmonary fibrosis, pulmonary hypertension, heart disorder, infection and malignancy, is also important for improved outcomes. Because PBC is often complicated by rheumatic disease, hepatologists should keep the possibility of systemic disorder in mind when examining PBC patients.

Distinct from its canonical effects, deletion of IL-12p40 induces cholangitis and fibrosis in interleukin-2Rα(-/-) mice

The IL-12 family modulates T cell mediated autoimmune diseases and GWAS in PBC have suggested a critical role of IL-12 and its subunits in modulating portal inflammation. We have taken advantage of an aggressive model of portal inflammation and colitis in IL-2Rα(-/-) mice to study the specific role of IL-12 and, in particular, the immunobiology of p40(-/-)IL-2Rα(-/-) mice. Colonies of IL-2Rα(+/-), IL-2Rα(-/-) and p40(-/-)IL-2Rα(-/-) mice were studied for the natural history of immunopathology in liver and colon using histology and immunohistochemistry. Further, to focus on mechanisms, liver, spleen and mesenteric lymph node flow cytometry was employed to identify specific phenotypes; cytokine analysis on inflammatory cell populations was compared between groups. Finally, Real-Time PCR was used to focus on the genes involved in hepatic fibrosis. Surprisingly, p40(-/-)IL-2Rα(-/-) mice manifest more severe portal inflammation and bile duct damage, including signs of portal hypertension and liver fibrosis, but a significant reduction in colitis. Indeed, p40(-/-)IL-2Rα(-/-) mice reveal a profound hepatic CD8(+) T cell infiltrate, whose major component are effector memory cells as well as enhanced hepatic Th1 but reduced Th17 responses. These observations were confirmed by Real-Time PCR analysis of fibrosis-related genes in the liver. Distinct from its canonical effects, IL-12p40 plays a critical role in autoimmune cholangitis, including hepatic fibrosis. These data take on striking significance for any proposed human trials that modulate the IL-12p40 pathway in human PBC.

Review article: controversies in the management of primary biliary cirrhosis and primary sclerosing cholangitis

BACKGROUND

Despite considerable advances over the last two decades in the molecular understanding of cholestasis and cholestatic liver disease, little improvement has been made in diagnostic tools and therapeutic strategies.

AIMS

To critically review controversial aspects of the scientific basis for common clinical practice in primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) and to discuss key ongoing challenges to improve patient management.

METHODS

We performed a literature search using PubMed and by examining the reference lists of relevant review articles related to the clinical management of PBC and PSC. Articles were considered on the background of the European Association for the Study of the Liver (EASL) and the American Association for the Study of Liver Diseases (AASLD) practice guidelines and clinical experience of the authors.

RESULTS

Ongoing challenges in PBC mainly pertain to the improvement of medical therapy, particularly for patients with a suboptimal response to ursodeoxycholic acid. In PSC, development of medical therapies and sensitive screening protocols for cholangiocarcinoma represent areas of intense research. To rationally improve patient management, a better understanding of pathogenesis, including complications like pruritis and fatigue, is needed and there is a need to identify biomarker end-points for treatment effect and prognosis. Timing of liver transplantation and determining optimal regimens of immunosuppression post-liver transplantation will also benefit from better appreciation of pre-transplant disease mechanisms.

CONCLUSION

Controversies in the management of PBC and PSC relate to topics where evidence for current practice is weak and further research is needed.

Concurrent autoimmune pancreatitis and primary biliary cirrhosis: a rare case report and literature review

Background

Both autoimmune pancreatitis (AIP) and primary biliary cirrhosis (PBC) are related to various diseases. But the concurrence of AIP and PBC is extremely rare, with only 2 cases reported. Here we report the concurrence of AIP and PBC in a Chinese patient for the first time.

Case presentation

A 65-year-old male was admitted to our hospital with jaundice, pruritus, mild abdominal pain and darkening urine. Serum alkaline phosphatase, γ-glutamyltransferase, bilirubin and IgG4 were prominently elevated. The antimitochondrial antibody was positive. Radiological examination revealed diffusive enlargement of the pancreas. Pancreatic biopsy showed lymphoplasmacytic infiltration, fibrosis and abundant IgG4+ plasma cells. The patient was diagnosed with AIP and PBC. Nasobiliary tube was placed to facilitate biliary drainage. A combination therapy of steroid and UDCA was administered and the patient was gradually recovered, during which the patient was complicated with biliary infecion, herpes zoster and pulmonary abscess.

Conclusion

We present this case together with literature evidence to support the concurrence of AIP and PBC, share our experience of using combination therapy with steroid and UDCA, and raise the awareness of infectious complications in immunosuppressed patients.

Role of Tim-3 in pathogenesis of inflammatory diseases of the digestive system

T cell immunoglobulin mucin domain-containing molecules (Tim)-3 is a type I cell membrane glycoprotein that is expressed on the surface of cells involved in innate and adaptive immunity. As the first discovered member of Tim family, Tim-3 participates in T cell-induced immune responses. By interacting with its ligands galectin-9 or PtdSer, Tim-3 induces cell apoptosis and clearance of apoptotic cells in autoimmune disorders, allergic diseases and virus infection-associated diseases. Tim-3 can act as a negative regulator of Th1/Th17 immune responses. Current research has shown that Tim-3 is involved in the pathogenesis of inflammatory diseases of the digestive system. Here we will review the progress in understanding the role of Tim-3 in the pathogenesis of inflammatory diseases of the digestive system.

Antimitochondrial antibody recognition and structural integrity of the inner lipoyl domain of the E2 subunit of pyruvate dehydrogenase complex

Antimitochondrial autoantibodies (AMAs), the serological hallmark of primary biliary cirrhosis, are directed against the lipoyl domain of the E2 subunit of pyruvate dehydrogenase (PDC-E2). However, comprehensive analysis of the amino acid residues of PDC-E2 lipoyl β-sheet with AMA specificity is lacking. In this study, we postulated that specific residues within the lipoyl domain are critical to AMA recognition by maintaining conformational integrity. We systematically replaced each of 19 residue peptides of the inner lipoyl domain with alanine and analyzed these mutants for reactivities against 60 primary biliary cirrhosis and 103 control sera. Based on these data, we then constructed mutants with two, three, or four replacements and, in addition, probed the structure of the substituted domains using thiol-specific spin labeling and electron paramagnetic resonance (EPR) of a (5)Ile→Ala and (12)Ile→Ala double mutant. Single alanine replacement at (5)Ile, (12)Ile, and (15)Glu significantly reduced AMA recognition. In addition, mutants with two, three, or four replacements at (5)Ile, (12)Ile, and (15)Glu reduced AMA reactivity even further. Indeed, EPR reveals a highly flexible structure within the (5)Ile and (12)Ile double-alanine mutant. Autoreactivity is largely focused on specific residues in the PDC-E2 lipoyl domain critical in maintaining the lipoyl loop conformation necessary for AMA recognition. Collectively, the AMA binding studies and EPR analysis demonstrate the necessity of the lipoyl β-sheet structural conformation in anti-PDC-E2 recognition.

Mechanism of autoimmune hepatic fibrogenesis induced by an adenovirus encoding the human liver autoantigen cytochrome P450 2D6

Autoimmune hepatitis type 2 (AIH-2) is a severe autoimmune liver disease with unknown etiology. We recently developed the CYP2D6 mouse model for AIH-2, in which mice are challenged with an adenovirus (Ad-2D6) expressing human cytochrome P450 2D6 (hCYP2D6), the major autoantigen in AIH-2. Such mice develop chronic hepatitis with cellular infiltrations and generation of hCYP2D6-specific antibodies and T cells. Importantly, the CYP2D6 model represents the only model displaying chronic fibrosis allowing for a detailed investigation of the mechanisms of chronic autoimmune-mediated liver fibrogenesis. We found that hCYP2D6-dependent chronic activation of hepatic stellate cells (HSC) resulted in an increased extracellular matrix deposition and elevated expression of α-smooth muscle actin predominantly in and underneath the liver capsule. The route of Ad-2D6 infection dramatically influenced the activation and trafficking of inflammatory monocytes, NK cells and hCYP2D6-specific T cells. Intraperitoneal Ad-2D6 infection caused subcapsular fibrosis and persistent clustering of inflammatory monocytes. In contrast, intravenous infection caused an accumulation of hCYP2D6-specific CD4 T cells throughout the liver parenchyma and induced a strong NK cell response preventing chronic HSC activation and fibrosis. In summary, we found that the location of the initial site of inflammation and autoantigen expression caused a differential cellular trafficking and activation and thereby determined the outcome of AIH-2-like hepatic damage and fibrosis.