Incidence and risk factors for hepatocellular carcinoma in primary biliary cirrhosis. Clin Rev Allergy Immunol. 2015;48:132-141. [PMID: 25762349 DOI: 10.1007/s12016-015-8483-x]

Primary biliary cholangitis

Primary biliary cholangitis is a chronic, autoimmune, cholestatic disease that mainly affects women aged 40-70 years. Recent epidemiological studies have shown an increasing incidence worldwide despite geographical heterogeneity and a decrease in the female-to-male ratio of those the disease affects. Similar to other autoimmune diseases, primary biliary cholangitis occurs in genetically predisposed individuals upon exposure to environmental triggers, specifically xenobiotics, smoking, and the gut microbiome. Notably, the diversity of the intestinal microbiome is diminished in individuals with primary biliary cholangitis. The intricate interplay among immune cells, cytokines, chemokines, and biliary epithelial cells is postulated as the underlying pathogenic mechanism involved in the development and progression of primary biliary cholangitis, and extensive research has been dedicated to comprehending these complex interactions. Following the official approval of obeticholic acid as second-line treatment for patients with an incomplete response or intolerance to ursodeoxycholic acid, clinical trials have indicated that peroxisome proliferator activator receptor agonists are promising additional second-line drugs. Future dual or triple drug regimens might reach a new treatment goal of normalisation of alkaline phosphatase levels, rather than a decrease to less than 1·67 times the upper limit of normal levels, and potentially improve long-term outcomes. Improvement of health-related quality of life with better recognition and care of subjective symptoms, such as pruritus and fatigue, is also an important treatment goal. Promising clinical investigations are underway to alleviate these symptoms. Efforts to facilitate better access to medical care and dissemination of current knowledge should enable diagnosis at an earlier stage of primary biliary cholangitis and ensure access to treatments based on risk stratification for all patients.

Hepatic immune regulation and sex disparities

Chronic liver disease is a major cause of morbidity and mortality worldwide. Epidemiology, clinical phenotype and response to therapies for gastrointestinal and liver diseases are commonly different between women and men due to sex-specific hormonal, genetic and immune-related factors. The hepatic immune system has unique regulatory functions that promote the induction of intrahepatic tolerance, which is key for maintaining liver health and homeostasis. In liver diseases, hepatic immune alterations are increasingly recognized as a main cofactor responsible for the development and progression of chronic liver injury and fibrosis. In this Review, we discuss the basic mechanisms of sex disparity in hepatic immune regulation and how these mechanisms influence and modify the development of autoimmune liver diseases, genetic liver diseases, portal hypertension and inflammation in chronic liver disease. Alterations in gut microbiota and their crosstalk with the hepatic immune system might affect the progression of liver disease in a sex-specific manner, creating potential opportunities for novel diagnostic and therapeutic approaches to be evaluated in clinical trials. Finally, we identify and propose areas for future basic, translational and clinical research that will advance our understanding of sex disparities in hepatic immunity and liver disease.

Patients with autoimmune liver disease have glucose disturbances that mechanistically differ from steatotic liver disease

Autoimmune liver diseases are associated with an increased risk of diabetes, yet the underlying mechanisms remain unknown. In this cross-sectional study, we investigated the glucose-regulatory disturbances in patients with autoimmune hepatitis (AIH, n = 19), primary biliary cholangitis (PBC, n = 15), and primary sclerosing cholangitis (PSC, n = 6). Healthy individuals (n = 24) and patients with metabolic dysfunction-associated steatotic liver disease (MASLD, n = 18) were included as controls. Blood samples were collected during a 120-min oral glucose tolerance test. We measured the concentrations of glucose, C-peptide, insulin, glucagon, and the two incretin hormones, glucose insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1). We calculated the homeostasis model assessment of insulin resistance (HOMA-IR), whole body insulin resistance (Matsuda index), insulin clearance, and insulinogenic index. All patient groups had increased fasting plasma glucose and impaired glucose responses compared with healthy controls. Beta-cell secretion was increased in AIH, PBC, and MASLD but not in PSC. Patients with AIH and MASLD had hyperglucagonemia and hepatic, as well as peripheral, insulin resistance and decreased insulin clearance, resulting in hyperinsulinemia. Patients with autoimmune liver disease had an increased GIP response, and those with AIH or PBC had an increased GLP-1 response. Our data demonstrate that the mechanism underlying glucose disturbances in patients with autoimmune liver disease differs from that underlying MASLD, including compensatory incretin responses in patients with autoimmune liver disease. Our results suggest that glucose disturbances are present at an early stage of the disease.NEW & NOTEWORTHY Patients with autoimmune liver disease but without overt diabetes display glucose disturbances early on in their disease course. We identified pathophysiological traits specific to these patients including altered incretin responses.

Role of sex in liver tumor occurrence and clinical outcomes: A comprehensive review

Clinical research on sex-based differences in the manifestations, pathophysiology, and prevalence of several diseases, including those affecting the liver, has expanded considerably in recent years. Increasing evidence suggests that liver diseases develop, progress, and respond to treatment differently depending on the sex. These observations support the concept that the liver is a sexually dimorphic organ in which estrogen and androgen receptors are present, which results in disparities between men and women in liver gene expression patterns, immune responses, and the progression of liver damage, including the propensity to develop liver malignancies. Sex hormones play protective or deleterious roles depending on the patient's sex, the severity of the underlying disease, and the nature of precipitating factors. Moreover, obesity, alcohol consumption, and active smoking, as well as social determinants of liver diseases leading to sex-related inequalities, may interact strongly with hormone-related mechanisms of liver damage. Drug-induced liver injury, viral hepatitis, and metabolic liver diseases are influenced by the status of sex hormones. Available data on the roles of sex hormones and gender differences in liver tumor occurrence and clinical outcomes are conflicting. Here, we critically review the main gender-based differences in the molecular mechanisms associated with liver carcinogenesis and the prevalence, prognosis, and treatment of primary and metastatic liver tumors.

Current Perspectives on the Molecular and Clinical Relationships between Primary Biliary Cholangitis and Hepatocellular Carcinoma

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterised by the immune-mediated destruction of small and medium intrahepatic bile ducts, with variable outcomes and progression. This review summarises the state of the art regarding the risk of neoplastic progression in PBC patients, with a particular focus on the molecular alterations present in PBC and in hepatocellular carcinoma (HCC), which is the most frequent liver cancer in these patients. Major risk factors are male gender, viral infections, e.g., HBV and HCV, non-response to UDCA, and high alcohol intake, as well as some metabolic-associated factors. Overall, HCC development is significantly more frequent in patients with advanced histological stages, being related to liver cirrhosis. It seems to be of fundamental importance to unravel eventual dysfunctional molecular pathways in PBC patients that may be used as biomarkers for HCC development. In the near future, this will possibly take advantage of artificial intelligence-designed algorithms.

Primary Biliary Cholangitis: Epidemiology, Diagnosis, and Presentation

Using ursodeoxycholic acid as a standard treatment and for its ability to test for antimitochondrial antibody to accelerate diagnosis, survival of primary biliary cholangitis patients has approached that of the general population, leading to a change in nomenclature from primary biliary cirrhosis to primary biliary cholangitis to more accurately describe the disease.

Autoimmune liver diseases and diabetes

Autoimmune liver diseases include autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. They are chronic, heterogenous diseases affecting the liver which is a key metabolic organ that ensures glucose homeostasis. It is well known that patients with other chronic liver diseases such as cirrhosis and nonalcoholic fatty liver disease (NAFLD) display glucose disturbances like insulin resistance and have an increased risk of diabetes. Previous evidence on glucose disturbances in patients with autoimmune liver disease is scarce but does point towards a potentially increased risk of type 1 diabetes and type 2 diabetes. The underlying mechanisms are unknown but may reflect genetic predisposition, concurrent NAFLD and or cirrhosis development, and treatment (steroid) related impairment of glucose homeostasis. Therefore, increased awareness and surveillance of diabetes development in patients with autoimmune liver disease may be important. Overall, detection and treatment of diabetes generally follow the usual diabetes guidelines; however, in patients with advanced liver cirrhosis, HbA1c may not be a reliable marker of average glucose levels, and treatment with insulin is generally recommended. In addition, it has recently been suggested that sodium-glucose cotransporter 2 inhibitors may be beneficial in treating refractory ascites. Further research on diabetes risk in autoimmune liver disease is warranted.

[Sex-specific differences in gastroenterological diseases]

Diseases of the gastrointestinal tract present with substantial sex differences that have a potential impact on patient outcome. This fact is not sufficiently addressed either in basic research or in clinical studies. For example, most animal studies utilize male animals. Despite differences in incidence, sex may affect complication rates, prognosis, or therapeutic response. The incidence of gastrointestinal cancers is frequently higher in males, but this observation cannot solely rely on a distinct risk behaviour. Here, differences in immune response and p53 signalling may be factors responsible for this finding. Nevertheless, taking sex differences into account and improving our understanding of relevant mechanisms is crucial and will most likely have a substantial impact on disease outcome. This overview aims to highlight sex differences in the context of various gastroenterological diseases, primarily to enhance awareness. Attention to sex-specific differences is essential to improve individualized treatment.

Efficacy evaluation and prognostic risk factors analysis of precise hepatectomy in the treatment of intermediate and advanced hepatocellular carcinoma

BACKGROUND

To investigate the efficacy of precise hepatectomy in the treatment of patients with intermediate and advanced hepatocellular carcinoma and analyze the risk factors affecting prognosis.

METHODS

Totally 104 patients with intermediate and advanced hepatocellular carcinoma from January 2018 to January 2019 were enrolled in this retrospective analysis. Of these, four patients lost to follow-up. Logistic regression was conducted to explore the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Compared with the control group, the precise hepatectomy decreased intraoperative blood loss (331.2928.91 to 203.29 ± 29.34 ml), operation time (198.29 ± 19.38 to 150.28 ± 18.27 min), perioperative blood transfusion volume (376.22 ± 25.93 to 228.29 ± 22.19 ml) (all P < 0.001). Logistic regression analysis of study group showed that hepatitis B infection (OR  = 1.746; 95% CI, 1.068-2.976), P  =  0.021, Child-Pugh classification (OR  =  2.319; 95% CI, 1.428-3.213), P < 0.001, Eastern Cooperative Oncology Group (ECOG) score (OR  =  2.287; 95% CI, 1.098-3.876; P  =  0.013) and Barcelona-Clinic Liver Cancer (BCLC) staging (OR = 2.029; 95% CI, 1.086-3.671; P = 0.022) were independent risk factors for prognosis of the precise hepatectomy.

CONCLUSION

Hepatitis B virus infection, Child-Pugh grade, ECOG score and BCLC staging grade were the independent risk factors affecting the prognosis of precise hepatectomy.

The unhealthy lifestyle in primary biliary cholangitis: An enemy to fight

BACKGROUND AND AIM

Metabolic dysfunctions, particularly hyperlipidemia, are a common finding in Primary Biliary Cholangitis (PBC). In presence of metabolic components of fatty-liver-disease (MAFLD), the liver fibrosis progression risk is higher. The aim of this study was to evaluate lifestyle of PBC patients compared to controls.

METHODS

In a prospective, multicenter study 107 PBC patients were enrolled; among these, 54 subjects were age-and sex-matched with 54 controls with a propensity-score-matching-analysis. Eating habits and physical activity were evaluated, respectively, with a food-frequency-questionnaire and with a short pre-validated-questionnaire. The adherence to Mediterranean diet was assessed with the alternate Mediterranean diet score.

RESULTS

The total fat intake was higher in controls than in PBC (p=0.004), unless above the national recommendations in both groups. Moreover, in PBC monounsaturated-fat and polyunsaturated-fatty-acid intakes and the adherence to Mediterranean diet were significantly lower than in controls (p<0.001, p=0.005 and p<0.001 respectively). Regarding physical activity, PBC subjects had a sedentary behavior as well as controls.

CONCLUSIONS

The lifestyle of both PBC and controls is at high risk of developing MAFLD. Therefore, hepatologists should regularly evaluate eating habits and physical activity in PBC patients and promote a lifestyle change to reduce liver disease progression risk.

Hepatocellular Carcinoma in Primary Biliary Cholangitis

Hepatocellular carcinoma (HCC) is potentially fatal complication affecting patients with primary biliary cholangitis (PBC). The incidence of HCC is 13 per 1000 person-years in patients with PBC cirrhosis, but much lower at 2.7 per 1000 person-years among patients with PBC without cirrhosis. Risk factors for the development of HCC in PBC include the presence of advanced fibrosis or cirrhosis and male sex, with some studies suggesting that treatment with ursodeoxycholic acid (UDCA) and UDCA response may reduce risk.

Characteristics and survival of patients with primary biliary cholangitis and hepatocellular carcinoma

BACKGROUND

Comprehensive and contemporary data pertaining large populations of patients with Primary Biliary Cholangitis (PBC) and hepatocellular carcinoma (HCC) are missing.

AIM

To describe main characteristics and outcome of PBC patients with HCC diagnosed in the new millennium.

METHODS

Analysing the Italian Liver Cancer registry we identified 80 PBC patients with HCC diagnosed after the year 2000, and described their clinical characteristics, access to treatment and survival.

RESULTS

Median age of patients was 71 years and 50.0% were males. Cirrhosis was present in 86.3% of patients, being well-compensated in 58.0%. Median HCC diameter was smaller in patients under surveillance (2.6 vs 4.0 cm, P = 0.007). Curative treatment, feasible in 50.0% of patients, was associated with improved survival compared to palliative and supportive care (42 vs 33 vs 6 months, P<0.0001). Surveillance was associated with a non-significant improved survival (36 vs 23 months), likely due to similar rate of curative treatment in patients under (51.4%) and outside surveillance (42.6%).

CONCLUSIONS

PBC patients with HCC are often elderly males with well-preserved liver function. Feasibility of curative treatment is high and associated with improved prognosis. Description of these patients may help focus surveillance to identify earlier tumours, increase their curability, and improve prognosis.

ABCC6 Knockdown Fuels Cell Proliferation by Regulating PPARα in Hepatocellular Carcinoma

The ATP binding cassette (ABC) transporter family is ubiquitous in eukaryotes, specifically in vertebrates, and plays a crucial role in energy homeostasis, cell signaling, and drug resistance. Accumulating evidence indicates that some ABC transporters contribute to cancer cell proliferation and tumor progression; however, relatively little is known about the behavior of the ABC transporter family in hepatocellular carcinoma (HCC). By analyzing two public transcriptomic databases, we evaluated the effect of genes in the ABC transporter family on HCC prognostic prediction; ABCC6 was selected for further study. Notably, ABCC6 was found to be downregulated in HCC tissues and correlated with favorable outcomes in patients with HCC. Moreover, ABCC6 knockdown not only significantly promoted cell proliferation in vitro and in vivo, but also inhibited cell cycle arrest and cell apoptosis. Transcriptome analysis revealed that ABCC6 depletion enhanced the “mitotic cell cycle” and “DNA replication” pathways, and suppressed the “PPAR signaling pathway”. Further investigation demonstrated that PPARα, one of the key regulators in peroxisome metabolism, is located downstream of ABCC6. In summary, our study provides profound insights into the behavior of ABC transporter family genes in various HCC cohorts, identifies ABCC6 as a biomarker for early-stage HCC diagnosis, and offers experimental basis for further investigations of targeting ABCC6 in the treatment of patients with HCC.

CircMIIP Contributes to Non-Small Cell Lung Cancer Progression by Binding miR-766-5p to Upregulate FAM83A Expression

BACKGROUND

Circular RNA migration and invasion inhibitory protein (circMIIP) is reported to be upregulated in non-small cell lung cancer (NSCLC) tissues compared with normal tissues. However, the role and working mechanism of circMIIP in NSCLC progression remain largely unclear.

METHODS

Cell proliferation ability was analyzed by colony formation assay, cell counting kit-8 (CCK-8) assay, and 5-ethynyl-2'-deoxyuridine assay. Cell apoptosis was assessed by flow cytometry. Transwell assays were performed to analyze the migration and invasion abilities of NSCLC cells. The interaction between microRNA-766-5p (miR-766-5p) and circMIIP or family with sequence similarity 83A (FAM83A) was validated by dual-luciferase reporter assay and RNA immunoprecipitation assay. Xenograft tumor model was established to analyze the role of circMIIP on tumor growth in vivo.

RESULTS

CircMIIP was highly expressed in NSCLC tissues and cell lines. CircMIIP knockdown restrained the proliferation, migration and invasion and induced the apoptosis of NSCLC cells. CircMIIP acted as a molecular sponge for miR-766-5p, and circMIIP silencing-mediated anti-tumor effects were largely overturned by the knockdown of miR-766-5p in NSCLC cells. miR-766-5p interacted with the 3' untranslated region (3'UTR) of FAM83A, and FAM83A overexpression largely reversed miR-766-5p accumulation-induced anti-tumor effects in NSCLC cells. CircMIIP competitively bound to miR-766-5p to elevate the expression of FAM83A in NSCLC cells. CircMIIP knockdown significantly restrained xenograft tumor growth in vivo.

CONCLUSION

CircMIIP promoted cell proliferation, migration and invasion and suppressed cell apoptosis in NSCLC cells through mediating miR-766-5p/FAM83A axis.

Hepatocellular carcinoma in primary sclerosing cholangitis and primary biliary cholangitis: a clinical and pathological study in an uncommon but emerging setting

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are biliary tract pathologies with increased risk of HCC, although HCC is more commonly associated with viral hepatitis and steatohepatitis. HCC risk stratification in PBC/PSC populations may help select patients for surveillance. We hypothesized that metabolic syndrome associated diagnoses and co-morbid nonalcoholic fatty liver disease (NAFLD) may be risk factors for HCC in patients with PBC and PSC. We undertook a multi-institutional case control study of PSC (19 cases, 38 controls) and PBC (39 cases and controls) patients with advanced fibrosis, matched for known HCC risk factors of age and sex, who had native liver explant or resection specimens. In the PSC population, HCC risk was significantly associated with multiple metabolic syndrome associated diagnoses (OR 13, p = 0.02), hyperlipidemia (OR 29, p = 0.03), and obesity (OR 6.8, p = 0.01). In the PBC cohort, only type 2 diabetes was a risk factor for HCC (OR 4.7, p = 0.03). In the PSC cohort, thick fibrous septae were associated with HCC risk (OR 3.4, p = 0.04). No other pathologic features of the nonneoplastic liver were significantly associated with HCC, including features of NAFLD such as macrovesicular steatosis, pericellular fibrosis, and steatohepatitis. Metabolic syndrome associated diagnoses, specifically type 2 diabetes among PBC patients, is associated with HCC risk in patients with biliary type cirrhosis. However, we found no evidence that HCC risk is related to co-morbid NAFLD, indicating a likely distinct mechanism of metabolic syndrome-associated carcinogenesis in these populations.

Incidence of Hepatocellular Carcinoma in Primary Biliary Cholangitis: A Systematic Review and Meta-Analysis

BACKGROUND

The risk and determinants of HCC in patients with primary biliary cholangitis (PBC) are unclear. We conducted a systematic review and meta-analysis of the incidence of HCC and risk factors associated with HCC risk among patients with PBC.

METHODS

We searched PubMed, EMBASE, MEDLINE, Cochrane databases and reference lists from relevant articles to identify cohort studies that examined incidence of HCC in patients with PBC from inception through November 2019.

RESULTS

A total of 29 studies including 22,615 patients met the eligibility criteria. The median cohort size was 292 patients followed for an average of 76 months. The pooled incidence rate for patients with PBC was 4.17 per 1000 patient-years (95% CI 3.17-5.47). On subgroup analysis, the incidence of HCC in patients with PBC cirrhosis was 15.7 per 1000 patient-years (95% CI 8.73-28.24). The HCC incidence rate was 9.82 per 1000 person-years (95% CI 5.92-16.28) in men and 3.82 per 1000 person-years (95% CI 2.85-5.11) in women.

CONCLUSIONS

Cirrhosis is the strongest risk factor for HCC in patients with PBC. Male gender was also a risk factor. Our meta-analysis supports current recommendations of HCC surveillance in patients with PBC cirrhosis. Further studies are needed to evaluate risk factors in this population.

XRCC2 repairs mitochondrial DNA damage and fuels malignant behavior in hepatocellular carcinoma

The effects of DNA damage repair (DDR) and mitochondrial dysfunction associated with HCC have been investigated, but the functional role of mitochondrial DDR in HCC remains elusive. We studied the DDR genes and identified XRCC2 as a potential prognostic marker for HCC. XRCC2 overexpression was detected in HCC cells and shown to promote the malignant behavior of cancer cells. XRCC2 depletion in HCC cells led to DNA damage accumulation at the replication site in the nucleus. Additionally, XRCC2-depleted HCC cells exhibited impaired mitochondrial respiration and reduced complex I (CI) activity as XRCC2 was responsible for elimination of mitochondrial DNA (mtDNA) damage and maintenance of mtDNA-encoded CI-related genes' transcription in a RAD51-dependent manner. We showed that tunicamycin (Tm)-activated sXBP1 bound to the TGTCAT domain and suppressed XRCC2 expression. In HCC patients, we observed a negative correlation between XBP1 and XRCC2 expression. Moreover, XRCC2 inhibition by Tm led to genomic and mtDNA damage, which impaired the transcription of mtDNA-encoded CI-related genes and prevented tumor proliferation in vivo. We described the role of XRCC2 in mtDNA damage repair and HCC progression while unveiling the potential anti-tumor effect of Tm.

Current Trends and Characteristics of Hepatocellular Carcinoma in Patients with Autoimmune Liver Diseases

Hepatocellular carcinoma (HCC), the commonest among liver cancers, is one of the leading causes of mortality among malignancies worldwide. Several reports demonstrate autoimmune liver diseases (AILDs), including autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) to confer increased risk of hepatobiliary malignancies, albeit at lower frequencies compared to other liver diseases. Several parameters have been recognized as risk factors for HCC development in AIH and PBC, including demographics such as older age and male sex, clinical features, the most decisive being cirrhosis and other co-existing factors, such as alcohol consumption. Moreover, biochemical activity and treatment response have been increasingly recognized as prognostic factors for HCC development in AIH and PBC. As available treatment modalities are effective only when HCC diagnosis is established early, surveillance has been proven essential for HCC prognosis. Considering that the risk for HCC is not uniform between and within disease groups, refinement of screening strategies according to prevailing demographic, clinical, and molecular risk factors is mandated in AILDs patients, as personalized HCC risk prediction will offer significant advantage in patients at high and/or medium risk. Furthermore, future investigations should draw attention to whether modification of immunosuppression could benefit AIH patients after HCC diagnosis.

The clinical and laboratory features associated with cancer in patients with primary biliary cholangitis: a longitudinal survey-based study

OBJECTIVES

To analyze the clinical and laboratory features of primary biliary cholangitis (PBC) patients complicated with cancer, and explore the potential factors associated with cancer.

METHODS

We consecutively enrolled PBC patients from January 2002 to February 2016 in Peking Union Medical College Hospital and performed a structured interview, systemic rheumatologic evaluation, and laboratory tests. The risk factors associated with cancer were analyzed with univariate and multivariable logistic regression and proportional hazard model.

RESULTS

Among the 580 PBC patients enrolled, 51 cancers were identified in 51 patients (8.8%), including 45 (88.2%) solid tumors and 6 (11.8%) hematologic malignancies. Patients with cancer were older (62.1 ± 9.6 vs. 55.4 ± 11.6 years, p < 0.01) than patients without cancer. Additionally, positive anti-centromere antibody (ACA) was more frequently observed in patients without cancer (25.9% vs 4.3%, p = 0.019) compared with patients with cancer diagnosed after establishing PBC. The median follow-up after the diagnosis of PBC was 4 years (IQR 2.0-6.6). Furthermore, multivariable logistic regression confirmed that older age was associated with cancer in PBC patients (odds ratio (OR) = 1.045, 95% confidence interval (CI): 1.006-1.085), and positive ACA was a protective factor (OR = 0.116, 95% CI: 0.015-0.876). Additionally, proportional hazard model analysis revealed that age was a risk factor (hazard ratio = 1.045, 95% CI: 1.012-1.080), and positive ACA was a protective factor (hazard ratio = 0.232, 95% CI: 0.055-0.977) for cancer.

CONCLUSIONS

Both solid tumor and hematologic malignancy were prevalent in PBC patients. Older age was associated with cancer, and positive ACA was a protective factor of cancer in PBC patients. Key Points • Patients with PBC could present with both solid tumors and hematologic malignancies. • Multivariable logistic regression and proportional hazard model analysis revealed that age was a risk factor as we know, and positive ACA was a protective factor.

Current understanding of primary biliary cholangitis

Primary biliary cholangitis (PBC) causes chronic and persistent cholestasis in the liver, eventually resulting in cirrhosis and hepatic failure without appropriate treatment. PBC mainly develops in middle-aged women, but it is also common in young women and men. PBC is considered a model of autoimmune disease because of the presence of disease-specific autoantibodies, that is, antimitochondrial antibodies (AMAs), intense infiltration of mononuclear cells into the bile ducts, and a high prevalence of autoimmune diseases such as comorbidities. Histologically, PBC is characterized by degeneration and necrosis of intrahepatic biliary epithelial cells surrounded by a dense infiltration of mononuclear cells, coined as chronic non-suppurative destructive cholangitis, which leads to destructive changes and the disappearance of small- or medium-sized bile ducts. Since 1990, early diagnosis with the detection of AMAs and introduction of ursodeoxycholic acid as first-line treatment has greatly altered the clinical course of PBC, and liver transplantation-free survival of patients with PBC is now comparable to that of the general population.

Surveillance for Hepatocellular Carcinoma

Patients with cirrhosis of the liver have a very high risk for developing hepatocellular carcinoma (HCC). Therefore, this group of patients should undergo surveillance to improve mortality. Better tools for stratifying the risk of HCC among patients with cirrhosis are needed. The best strategy for surveillance is the combination of alpha-fetoprotein and ultrasound of the liver every 6 months. This strategy shows a sensitivity of approximately 65% and a specificity of 90%, and importantly, has been shown to improve mortality in these patients. Balancing benefits and harms should be performed when deciding to proceed with surveillance.

hsa_circ_0001955 Enhances In Vitro Proliferation, Migration, and Invasion of HCC Cells through miR-145-5p/NRAS Axis

Increasing circular RNAs (circRNAs) have been reported to act as key players in human malignancies. However, the expression, role, and mechanism of circRNAs in HCC are not well elucidated. In this study, some differentially expressed circRNAs (DECs) between hepatocellular carcinoma (HCC) and normal tissues were identified using three circRNA microarrays (Gene Expression Omnibus [GEO]: GSE78520, GSE94508, and GSE97332). Twenty-one DECs were found to be commonly upregulated in all the three datasets. Among the 21 DECs, hsa_circ_0001955 ranked as the top three most upregulated DECs in GEO: GSE78520, GSE94508, and GSE97332. Moreover, hsa_circ_0001955 expression in HCC cells and tissues was significantly higher than that in corresponding normal controls. Functional experiments revealed that knockdown of hsa_circ_0001955 markedly inhibited proliferation, migration, and invasion of HCC, and its overexpression led to the opposite effects. hsa_circ_0001955 was mainly located in the cytoplasm, in which hsa_circ_0001955 could directly bind to miR-145-5p. miR-145-5p was downregulated in HCC, and its expression was negatively linked to hsa_circ_0001955 expression. Furthermore, we identified that NRAS was a downstream direct target of the hsa_circ_0001955/miR-145-5p axis in HCC. Collectively, our findings demonstrate the oncogenic roles of the hsa_circ_0001955/miR-145-5p/NRAS axis in HCC, which may represent a potential therapeutic target for HCC.

Androgen receptor affects the response to immune checkpoint therapy by suppressing PD-L1 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a heterogeneous malignancy with gender-related differences in onset and course. Androgen receptor (AR), a male hormone receptor, is critical in the initiation and progression of HCC. The role of AR in HCC has been mechanistically characterized and anti-AR therapies have been developed, showing limited efficacy. Immunotherapy targeting immune checkpoint proteins may substantially improve the clinical management of HCC. The mechanism by which AR influences HCC immune state remains unclear. In this study, we demonstrated that AR negatively regulated PD-L1, by acting as a transcriptional repressor of PD-L1. Notably, AR over-expression in HCC cells enhanced CD8⁺T function in vitro. We then verified the AR/PD-L1 correlation in patients. In animal experiment we found that lower AR expressed tumor achieved better response to PD-L1 inhibitor. Thus, AR suppressed PD-L1 expression, possibly contributing to gender disparity in HCC. Better understanding of the roles of AR during HCC initiation and progression will provide a novel angle to develop potential HCC immunotherapies.

Epidemiology and clinical course of primary biliary cholangitis in the Asia-Pacific region: a systematic review and meta-analysis

AIMS

Epidemiological studies on primary biliary cholangitis (PBC) show heterogeneity. The aim of the present study was to synthesize the prevalence, incidence and clinical course of PBC in the Asia-Pacific region.

METHODS

PubMed, Medline, Cochrane library and EMBASE were searched for epidemiology and clinical course of PBC published up to July, 2019. Meta-analysis was conducted on the epidemiology and clinical course (decompensation, hepatocellular carcinoma and death/liver transplantation) of PBC patients. Random-effect model and fixed-effect model were used to evaluate the pooled prevalence, incidence, mortality/liver transplantation and their 95% confidence intervals as appropriate. Subgroup analysis was performed by stratification with gender, pre- and post-UDCA era, sub-region and publication year. Meta-regression was used to examine the heterogeneity.

RESULTS

Out of 3460 studies, 18 studies from 7 countries/regions were finally included. The overall prevalence of PBC was 118.75 cases per million (95% CI 49.96-187.55) in the Asia-Pacific region, with the high, medium and low prevalence being in Japan and China (191.18 cases per million), New Zealand (99.16 cases per million) and South Korea and Australia (39.09 cases per million), respectively. The incidence of PBC was 8.55 cases per million per year (95% CI 8.05-9.06). The 5-year accumulative incidence of decompensation, HCC and death/liver transplantation in PBC patients was 6.95% (95% CI 2.07-11.83%), 1.54% (95% CI 0.9-2.19%) and 4.02% (95% CI 2.49-5.54%), respectively.

CONCLUSION

In the Asia-Pacific region, the prevalence and incidence of PBC are higher than once expected. PBC tends to be diagnosed at older age and has a relatively low incidence of HCC in this region.

Prognosis of 732 ursodeoxycholic acid-treated patients with primary biliary cholangitis: A single center follow-up study from China

BACKGROUND AND AIM

The impact of male sex and past hepatitis B virus (HBV) infection on survival of primary biliary cholangitis (PBC) are issues at discussion. The aim of the present study was to identify risk factors for transplant-free survival (TRS) in Chinese PBC patients who received ursodeoxycholic acid (UDCA), with special focus on the impact of male sex and past HBV infection.

METHODS

We followed up PBC patients who received UDCA at our institute between January 2000 and December 2017 until their death, liver transplantation, or censored on April 1, 2018, by interview and review of medical records. We used Cox proportional hazards model and Kaplan-Meier method.

RESULTS

Out of 976 PBC patients, 732 UDCA-treated patients (female : male = 6.2:1) with required clinical and laboratory data were enrolled in this study. The median follow-up period were 4.8 years (interquartile range: 2.8-7.1 years). The overall 5-, 10-, and 15-year TRS rates were 86.7% (95% CI: 83.8-88.1), 71.1% (95% CI: 65.0-77.2), and 59.2% (95% CI: 44.5-73.9), respectively. The survival was significantly worse for male patients and older patients (≥ 55 years) (log-rank test: P < 0.05 for both). On multivariate analysis, male sex, cirrhosis, serum bilirubin, and serum albumin were independent predictors for TRS. There was no significant difference in survivals between patients with (n = 167) and without (n = 219) past HBV infection (log-rank test: P = 0.293).

CONCLUSIONS

In this large Chinese cohort of UDCA-treated PBC patients, male sex was associated with shorter survival, whereas past HBV infection was not associated with poorer outcome.

Real impact of liver cirrhosis on the development of hepatocellular carcinoma in various liver diseases-meta-analytic assessment

Background

It is well known that the incidence of developing hepatocelluler carcinoma (HCC) is increased in liver cirrhosis of different etiologies. However, comparison of HCC incidence in various liver diseases has not yet been estimated. We surveyed this comparison.

Methods

The PubMed database was examined (1989‐2017) for studies published in English language regarding the prospective follow‐up results for the development of HCC in various liver diseases. A meta‐analysis was performed for each liver disease.

Results

The annual incidence (%) of HCC in the non‐cirrhotic stage and cirrhotic stage, and the ratio of HCC incidence in the cirrhotic stage/non‐cirrhotic stage were as follows. (a) hepatitis B virus liver disease: 0.37%→3.23% (8.73‐fold), (b) hepatitis C virus liver diseases: 0.68%→4.81% (7.07‐fold), (c) primary biliary cholangitis (0.26%→1.79%, 6.88‐fold), (d) autoimmune hepatitis (0.19%→0.53%, 2.79‐fold), and (e) NASH (0.03%→1.35%, 45.00‐fold). Regarding primary hemochromatosis and alcoholic liver diseases, only follow‐up studies in the cirrhotic stage were presented, 1.20% and 2.06%, respectively.

Conclusions

When the liver diseases advance to cirrhosis, the incidence of HCC is markedly increased. The development of HCC must be closely monitored by ultrasonography, magnetic resonance imaging, and computed tomography, irrespective of the different kinds of liver diseases.

Changes in the Epidemiology of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is considered a model autoimmune disease, characterized by circulating anti-mitochondrial antibodies and a selective autoimmune destruction of intrahepatic cholangiocytes. PBC is heterogeneous in its presentation, symptomatology, disease progression, and response to therapy. The pathogenesis is still largely unknown and epidemiologic studies have facilitated the identification of risk factors and the understanding of disease prevalence, geographic variations, heterogeneity, and differences in sex ratio. Recent studies from large international cohorts have better identified prognostic factors suggesting a change in patient management based on risk-stratification tools to identify subgroups at greatest potential benefit from second-line therapies.

Patterns of disease progression and incidence of complications in primary biliary cholangitis (PBC)

Clinical outcome for patients with primary biliary cholangitis (PBC) is dictated by development of cirrhosis, portal hypertension and its associated complications; including for some, a predisposition toward hepatocellular carcinoma. However rates of clinical progression vary, and accurately identifying disease course is of critical importance to patients, clinicians, as well as industry, who are committed to developing new effective and life-prolonging therapy as well as treating symptoms that appear disproportionate to underlying disease severity. Patients seek reassurance and guidance as to their own prognosis, and clinicians wish to confidently recognise those at highest risk of poor outcomes as equally as they strive to reassure individuals with a more favourable disease trajectory. International registries have facilitated a much greater knowledge of disease incidence and heterogeneity of presenting phenotypes. In so doing they highlight the opportunity to provide a more individualized estimate of the clinical course that patients experience, and have led to a renewed approach to risk stratification; both in terms of 'hard outcomes' and also disease-associated complications in PBC specifically.

Primary biliary cholangitis is more severe in previous hepatitis B virus infection patients

OBJECTIVES

The aim of this study was to evaluate the association between previous hepatitis B virus (HBV) infection and the severity of primary biliary cholangitis (PBC).

PATIENTS AND METHODS

A total of 379 HBsAg-negative PBC patients were investigated between 2012 and 2017 in this study. Fifty-two of these patients underwent liver biopsy. The enrolled patients were divided into an anti-HBc-positive group and an anti-HBc-negative group; the patients with liver biopsy were further divided into early stage (stage I) and advanced stage (stages II, III, and IV) according to histological assessment. Liver fibrosis was also assessed by noninvasive prognosis scores including the Mayo Risk Score, the Newcastle model, the aspartate aminotransferase-to-platelet ratio index, the fibrosis index based on the four factors (FIB-4), and the albumin-bilirubin score. The difference in disease stage between the two groups was assessed by histological stage and noninvasive scores predicting fibrosis.

RESULTS

The histology showed that more patients in the anti-HBc-positive group had advanced stage compared with anti-HBc-negative patients (P<0.05). Higher Mayo Risk Score, the Newcastle model, aminotransferase-to-platelet ratio index, and fibrosis index based on the four factors (all P<0.05) were obtained in all patients except for the albumin-bilirubin score (P=0.096).

CONCLUSION

Previous HBV infection was associated with a worse histological stage and advanced fibrosis score of PBC. It appears that the previous HBV infection may have aggravated the PBC severity, potentially leading to poorer outcomes.

Screening therapeutic targets of ribavirin in hepatocellular carcinoma

The objective of the present study was to screen the key genes of ribavirin in hepatocellular carcinoma (HCC) and provide novel therapeutic targets for HCC treatment. The mRNA expression datasets of GSE23031 and GSE74656, as well as the microRNA (miRNA) expression dataset of GSE22058 were downloaded from the Gene Expressed Omnibus database. In the GSE23031 dataset, there were three HCC cell lines treated with PBS and three HCC cell lines treated with ribavirin. In the GSE74656 dataset, five HCC tissues and five carcinoma adjacent tissues were selected. In the GSE22058 dataset, 96 HCC tissues and 96 carcinoma adjacent tissues were selected. The differentially expressed genes (DEGs) and differentially expressed miRNAs were identified via the limma package of R. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was performed with the Database for Annotation, Visualization and Integrated Discovery. The target mRNAs of DEMs were obtained with TargetScan. A total of 559 DEGs (designated DEG-Ribavirin) were identified in HCC cells treated with ribavirin compared with PBS and 632 DEGs (designated DEG-Tumor) were identified in HCC tissues compared with carcinoma adjacent tissues. A total of 220 differentially expressed miRNAs were identified in HCC tissues compared with carcinoma adjacent tissues. In addition, 121 GO terms and three KEGG pathways of DEG-Ribavirin were obtained, and 383 GO terms and 25 KEGG pathways of DEG-Tumor were obtained. A total of five key miRNA-mRNA regulated pairs were identified, namely miR-183→CCNB1, miR-96→DEPDC1, miR-96→NTN4, miR-183→NTN4 and miR-145→NTN4. The present study indicated that certain miRNAs (including miR-96, miR-145 and miR-183) and mRNAs (including NAT2, FBXO5, CCNB1, DEPDC1 and NTN4) may be associated with the effects of ribavirin on HCC. Furthermore, they may provide novel therapeutic targets for HCC treatment.

Chronic Autoimmune Epithelitis in Sjögren's Syndrome and Primary Biliary Cholangitis: A Comprehensive Review

Within the spectrum of autoimmune diseases, Sjögren's syndrome and primary biliary cholangitis are exemplary and can be coined as chronic epithelitis based on their frequent coexistence in clinical practice and the highly specific immune-mediated injury of the small bile ducts and the exocrine glands. The pathogenic mechanisms underlying the diseases are similar, with apoptosis being the key element leading to organ-specific immune-mediated injury directed against the small bile ducts and salivary gland epithelia, respectively along with similar epidemiological features, such as female predominance and the age of onset in the fifth decade of life. Indeed, novel insights into the pathogenesis of the diseases have been obtained in recent years, including a better definition of the role of B and T cells, particularly Th17 cells, and the mechanisms of autoantibody-mediated tissue injury, with anti-mitochondrial antibodies and SS-A/SS-B being identified as specific for primary biliary cholangitis and Sjögren's syndrome, respectively. These findings have opened the possibility to new targeted therapies, but most clinical needs remain unmet, particularly from a therapeutic standpoint where options diverge, with bile acids being the predominant treatment strategy in primary biliary cholangitis and immunomodulators being used to treat Sjögren's syndrome. Here we provide a comprehensive review of the most recent findings on the pathogenesis, clinical manifestations and therapeutic options for Sjögren's syndrome and primary biliary cholangitis, respectively, while stressing the common traits between these conditions. Our cumulative hypothesis is that similarities outnumber differences and that this may prove advantageous towards a better management of patients.

Geoepidemiology and changing mortality in primary biliary cholangitis

Primary biliary cholangitis (PBC), formerly called primary biliary cirrhosis, is a chronic cholestatic disease characterized by an autoimmune-mediated destruction of small and medium-sized intrahepatic bile ducts. Originally PBC was considered to be rare and almost invariably fatal, mainly because the diagnosis was made in patients presenting with advanced symptomatic disease (jaundice and decompensated cirrhosis). However, the development of a reproducible indirect immunofluorescence assay for antimitochondrial antibody made it possible to diagnose the disease at an earlier stage, and introduction of ursodeoxycholic acid therapy as the first-line therapy for PBC drastically changed PBC-related mortality. At present, patients with an early histological stage have survival rates similar to those of an age- and sex-matched control population. Although 30% of patients treated with ursodeoxycholic acid may exhibit incomplete responses, obeticholic acid and drugs currently in development are expected to be effective for these patients and improve outcomes. Meanwhile, more etiology and immunopathology studies using new technologies and novel animal models are needed to dissect variances of clinical course, treatment response, and outcome in each patient with PBC. Precision medicine that is individualized for each patient on the basis of the cause identified is eagerly awaited.

Risk factors for recurrence of primary biliary cholangitis after liver transplantation in female patients: A Japanese multicenter retrospective study

Primary biliary cholangitis (PBC) is diagnosed mainly in female individuals, and risk factors for PBC recurrence (rPBC) after liver transplantation (LT) from cadaveric donors have been reported. We conducted a retrospective multicenter study of rPBC in female patients after living‐donor LT (LDLT). A total of 388 female patients undergoing LDLT for end‐stage PBC were enrolled, and the effects of preoperative and operative factors were evaluated. Postoperative factors were evaluated in 312 patients who survived for more than 1 year post‐LDLT. rPBC was defined as abnormal hepatic enzyme levels with typical histological findings in liver biopsies. Fifty‐eight patients (14.9%) developed rPBC with a median of 4.6 (0.8‐14.5) years post‐LT. Cox hazard analysis (P < 0.05) showed that younger recipient age (hazard ratio, 0.95; 95% confidence interval, 0.920‐0.982), shorter operative time (1.00; 0.995‐0.999), higher serum immunoglobulin M level (1.00; 1.001‐1.002), donor sex mismatch (2.45; 1.268‐4.736), human leukocyte antigen B60 (2.56; 1.336‐4.921) and DR8 (1.98; 1.134‐3.448), and initial treatment with cyclosporine A (3.14; 1.602‐6.138) were significantly associated with rPBC. The frequencies of Child‐Turcotte‐Pugh class C (0.46; 0.274‐0.775), the model of end‐stage liver disease score (0.96; 0.914‐0.998), and updated Mayo risk score (1.02; 1.005‐1.033) were significantly lower in rPBC. Posttransplantation use of steroids decreased and that of antimetabolites increased the frequency of rPBC. Conclusion: The timing of LT, recipient conditions, donor characteristics, and immunosuppressive medications may be associated with rPBC in LT recipients. (Hepatology Communications 2017;1:394–405)

Recent advances in the diagnosis and treatment of primary biliary cholangitis

Primary biliary cholangitis (PBC), formerly referred to as primary biliary cirrhosis, is an infrequent progressive intrahepatic cholestatic autoimmune illness that can evolve into hepatic fibrosis, hepatic cirrhosis, hepatic failure, and, in some cases, hepatocellular carcinoma. The disease itself is characterized by T-lymphocyte-mediated chronic non-suppurative destructive cholangitis and elevated serum levels of extremely specific anti-mitochondrial autoantibodies (AMAs). In this article, we will not only review epidemiology, risk factors, natural history, predictive scores, radiologic approaches (e.g., acoustic radiation force impulse imaging, vibration controlled transient elastography, and magnetic resonance elastography), clinical features, serological characteristics covering biochemical markers, immunoglobulins, infections markers, biomarkers, predictive fibrosis marker, specific antibodies (including AMAs such as AMA-M2), anti-nuclear autoantibodies [such as anti-multiple nuclear dot autoantibodies (anti-sp100, PML, NDP52, anti-sp140), anti-rim-like/membranous anti-nuclear autoantibodies (anti-gp210, anti-p62), anti-centromere autoantibodies, and some of the novel autoantibodies], histopathological characteristics of PBC, diagnostic advances, and anti-diastole of PBC. Furthermore, this review emphasizes the recent advances in research of PBC in terms of therapies, including ursodeoxycholic acid, budesonide, methotrexate, obeticholic acid, cyclosporine A, fibrates such as bezafibrate and fenofibrate, rituximab, mesenchymal stem cells transplant, and hepatic transplant. Currently, hepatic transplant remains the only optimal choice with acknowledged treatment efficiency for end-stage PBC patients.

The Natural History and Prognosis of Primary Biliary Cirrhosis with Clinical Features of Autoimmune Hepatitis

Although a variant of primary biliary cirrhosis (PBC) characterized by features of autoimmune hepatitis (AIH) has been recognized for many years, few studies with ample numbers of patients have focused on its natural history. This study aimed to clarify the natural history, prognosis, and response to therapy in a cohort of patients with PBC with AIH features. We retrospectively analyzed 277 PBC patients without AIH features and 46 PBC patients with AIH features seen between September 2004 and April 2014. The 5-year adverse outcome-free survival of PBC patients with AIH features was 58% compared to 81% in PBC patients without AIH features. Multivariate analysis in the patients with AIH features indicated that total bilirubin ≥ 2.70× the upper limit of normal predicted a poor prognosis (p = 0.008, relative risk 8.39, 95% confidence interval (CI) 1.73, 40.73). Combination therapy with ursodeoxycholic acid (UDCA) and immunosuppression provided better short-term responses in PBC patients with AIH features, defined by multiple criteria. Higher aspartate aminotransferase (AST) level at accession suggested better prognosis for PBC patients with AIH features while worse prognosis for PBC patients without AIH features. PBC patients with AIH features differ from those without AIH features in terms of natural history, prognostic indicators, and response to therapy.

Association between anti-HBc positivity and hepatocellular carcinoma in HBsAg-negative subjects with chronic liver disease: A meta-analysis

A meta-analysis was performed to ascertain to what extent hepatitis B surface antigen (HBsAg)-negative/anti-hepatitis B core (anti-HBc)-positive subjects with chronic liver disease are at a higher risk of developing hepatocellular carcinoma (HCC) than the anti-HBc-negative.All studies included had to fulfill the following characteristics and inclusion criteria: they investigated the relationship between HBsAg-negative/anti-HBc-positive serology and the occurrence of HCC, whether a case-control or cohort study, they provided relative risk (RR) or odds ratios (ORs) and 95% confidence intervals (CIs), were available as a full text written in English, and were published and indexed up to April 2015.Twenty-six original studies met the inclusion criteria, allowing a meta-analysis on 44,553 patients. The risk of HCC among the 9986 anti-HBc-positive subjects was 67% higher than in the 34,567 anti-HBc-negative (95% CI = 1.44-1.95, P < 0.0001). The results were similar when groups of patients with a different stage of liver disease (patients with chronic liver disease, patients with cirrhosis), with different ethnicity (Asian and non-Asian) and etiology (HCV and non-HCV) were considered. The risk of HCC was significantly higher in the 651 anti-HBs/anti-HBc-positive patients (RR = 1.36; 95% CI = 1.17-1.58, P = 0.03) and in the 595 anti-HBs-negative/anti-HBc-positive subjects (RR = 2.15; 95% CI = 1.58-2.92, P < 0.0001) than in the 1242 anti-HBs/anti-HBc negative. However, the RR from 8 studies indicated that the risk of HCC was 35% lower among the anti-HBs/anti-HBc-positive subjects compared to the anti-HBs-negative/anti-HBc-positive (RR = 0.65; 95% CI = 0.52-0.8, P < 0.0001).This meta-analysis shows that in HBsAg-negative subjects with chronic liver disease, anti-HBc positivity is strongly associated with the presence of HCC, an association observed in all subgroups according to the stage of the disease, etiology, and ethnicity.

Adaptive immunity in the liver

The anatomical architecture of the human liver and the diversity of its immune components endow the liver with its physiological function of immune competence. Adaptive immunity is a major arm of the immune system that is organized in a highly specialized and systematic manner, thus providing long-lasting protection with immunological memory. Adaptive immunity consists of humoral immunity and cellular immunity. Cellular immunity is known to have a crucial role in controlling infection, cancer and autoimmune disorders in the liver. In this article, we will focus on hepatic virus infections, hepatocellular carcinoma and autoimmune disorders as examples to illustrate the current understanding of the contribution of T cells to cellular immunity in these maladies. Cellular immune suppression is primarily responsible for chronic viral infections and cancer. However, an uncontrolled auto-reactive immune response accounts for autoimmunity. Consequently, these immune abnormalities are ascribed to the quantitative and functional changes in adaptive immune cells and their subsets, innate immunocytes, chemokines, cytokines and various surface receptors on immune cells. A greater understanding of the complex orchestration of the hepatic adaptive immune regulators during homeostasis and immune competence are much needed to identify relevant targets for clinical intervention to treat immunological disorders in the liver.

Xenobiotics and loss of tolerance in primary biliary cholangitis

Data from genome wide association studies and geoepidemiological studies established that a combination of genetic predisposition and environmental stimulation is required for the loss of tolerance in primary biliary cholangitis (PBC). The serologic hallmark of PBC are the presence of high titer anti-mitochondrial autoantibodies (AMA) that recognize the lipoyl domain of the mitochondrial pyruvate dehydrogenase E2 (PDC-E2) subunit. Extensive efforts have been directed to investigate the molecular basis of AMA. Recently, experimental data has pointed to the thesis that the breaking of tolerance to PDC-E2 is a pivotal event in the initial etiology of PBC, including environmental xenobiotics including those commonly found in cosmetics and food additives, suggesting that chemical modification of the PDC-E2 epitope may render its vulnerable to become a neo-antigen and trigger an immune response in genetically susceptible hosts. Here, we will discuss the natural history, genetics and immunobiology of PBC and structural constraints of PDC-E2 in AMA recognition which makes it vulnerable to chemical modification.