No rise in incidence but geographical heterogeneity in the occurrence of primary biliary cirrhosis in North East England

Identification of Crosstalk Genes Between Primary Sjögren's Syndrome and Primary Biliary Cirrhosis by Transcriptome Analysis

BACKGROUND

Growing evidence points a connection between Primary Sjögren's Syndrome (pSS) and Primary Biliary Cholangitis (PBC). This study seeks to identify the crosstalk genes between them.

METHOD

Transcriptomic datasets for pSS (GSE66795) and PBC (GSE119600) were sourced from the Gene Expression Omnibus (GEO) database. Common genes between these two conditions were detected using Differential Expression Analysis and Weighted Gene Co-expression Network Analysis (WGCNA). Potential crosstalk genes were pinpointed through Least Absolute Shrinkage and Selection Operator (LASSO) regression. Validation of these genes were performed through single-sample gene set enrichment analysis (ssGSEA), multivariable logistic regression, and single-cell transcriptome analysis.

RESULT

Differential expression analysis showed 339 commonly upregulated DEGs in both pSS and PBC. WGCNA analysis revealed 11 modules associated with pSS and 7 modules associated with PBC. Subsequently, 56 core genes were found to overlap between the genes identified by differential expression analysis and WGCNA. LASSO regression identified CX3CR1, ELF1, CUL1, PARP3, DDX60, SP140L, and MUC1 as pivotal crosstalk genes for both pSS and PBC. Moreover, ssGSEA analysis and multivariable logistic regression underscored the potential of these 7 genes as crosstalk genes. Single-cell analyses revealed higher proportions of NK cells, CD4+ T cells, and CD8+ T cells in pSS patients, with prominent expression of CX3CR1, ELF1, CUL1, PARP3, DDX60, SP140L, and MUC1 in these cells.

CONCLUSION

Our study identified CX3CR1, ELF1, CUL1, PARP3, DDX60, SP140L and MUC1 as crosstalk genes between pSS and PBC, and highlighted the critical role of NK cells, CD4+ T cells and CD8+ T cells in disease mechanisms.

Clinical management of autoimmune liver diseases: juncture, opportunities, and challenges ahead

The three major autoimmune liver diseases are autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC).These conditions are assumed to result from a breakdown in immunological tolerance, which leads to an inflammatory process that causes liver damage.The self-attack is started by T-helper cell-mediated identification of liver autoantigens and B-cell production of autoantibodies,and it is maintained by a reduction in the number and activity of regulatory T-cells.Infections and environmental factors have been explored as triggering factors for these conditions, in addition to a genetic predisposition.Allelic mutations in the HLA locus have been linked to vulnerability, as have relationships with single nucleotide polymorphisms in non-HLA genes.Despite the advances in the management of these diseases, there is no curative treatment for these disorders, and a significant number of patients eventually progress to an end-stage liver disease requiring liver transplantation.In this line, tailored immune-therapeutics have emerged as possible treatments to control the disease.In addition, early diagnosis and treatment are pivotal for reducing the long-lasting effects of these conditions and their burden on quality of life.Herein we present a review of the etiology, clinical presentation, diagnosis, and challenges on ALDs and the feasible solutions for these complex diseases.

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.

Evolutionary relationship between antimitochondrial antibody positivity and primary biliary cholangitis in Taiwan: a 16-year hospital cohort study

Background

How antimitochondrial antibody (AMA)-positive patients evolve to have primary biliary cholangitis (PBC) in viral hepatitis-endemic areas is unknown.

Objectives

We aimed to investigate this evolution in Taiwan.

Design/methods

A 16-year medical center-based cohort study of 2,095,628 subjects was conducted in Taiwan, an Asian country endemic to viral hepatitis. AMA-positive subjects were those with positive AMA with alkaline phosphatase (ALP) ⩽1.5 times the upper limit of normal (ULN), and PBC was defined as positive AMA with ALP >1.5 × ULN.

Results

AMA-positive subjects had a lower average age- and sex-adjusted prevalence than PBC patients (4.68/105 versus 11.61/105, p = 0.0002), but their incidence was comparable (0.99/105 versus 1.12/105, p = 0.36). The former group had a borderline significantly lower mean age (56.59 years versus 58.10 years, p = 0.06) and a lower female-to-male ratio (2.85:1 versus 5.44:1, p < 0.0001). Both AMA-positive subjects (prevalence change: 20.0%, p < 0.01; incidence change: -9.2%, p < 0.01) and PBC patients (prevalence change: 14.6%, p < 0.01; incidence change: -4.7%, p < 0.01) prevalence rate increased but the incidence rate decreased. Among the 423 AMA-positive subjects, 77 (18.2%) developed PBC, for a mean duration of 1.757 years. Compared with AMA-positive subjects, PBC patients had similar concurrent chronic hepatitis B (CHB) rates (2.7% versus 4.3%, p = 0.197) but lower chronic hepatitis C (CHC) rates (3.69% versus 15.60%, p < 0.01).

Conclusion

PBC was more prevalent than AMA-positive subjects, and PBC patients had a higher female-to-male ratio than AMA-positive subjects, of whom 18.2% developed PBC (mean lag: 1.757 years). Upward trends in prevalence rates and downward trends in incidence rates were noted for both AMA-positive subjects and PBC. CHB was rare, CHC was more prevalent among PBC patients than the general population, and CHC was less prevalent among PBC than among AMA-positive subjects.

Characteristic geoepidemiology of primary biliary cholangitis in Taiwan: A nationwide population-based study

AIM

Data on the geoepidemiology and outcomes of primary biliary cholangitis (PBC) in Asia are limited; thus, we aimed to collect and assess this information for Taiwan.

METHODS

A nationwide population-based cohort study was undertaken using data from the Taiwan National Health Insurance Research Database. Primary biliary cholangitis was defined by the International Classification of Diseases, Ninth Revision, Clinical Modification code 571.6 based on alkaline phosphatase and antimitochondrial antibody measurements and ursodeoxycholic acid treatment.

RESULTS

During 2002-2015, 2737 patients (2137 female patients; mean age, 57.78 years) had PBC. The average annual age- and sex-adjusted prevalence and incidence rates of PBC were 8.092/105 and 1.148/105 , respectively. Prevalent cases peaked in patients aged 50-59 years; the female-to-male ratio was 4.21. Annual prevalence rates increased with time (average percentage change, 12.03%; p < 0.0001). The annual incidence rates decreased with time (-7.39%; p = 0.000011) in female patients (-8.94%; p = 0.000003) but remained steady in male patients. Female-to-male and northern-to-southern relative risks of PBC incidence rates ranged from 2.2675 to 4.3318 and from 1.5707 to 3.1725, respectively. The 14-year hepatocellular carcinoma (HCC) cumulative incidence was 9.11%, and the mortality rate was 32.44%; the cumulative incidences of dyslipidemia, thyroid disease, and extrahepatic cancers were 65.13%, 24.40%, and 12.79%, respectively. Higher cumulative incidences of HCC (p = 0.0064) and mortality (p < 0.0001) were noted in male than female PBC patients; southern Taiwan PBC patients had higher cumulative incidences of mortality (p < 0.0001) than their northern counterparts.

CONCLUSION

In Taiwan, decreasing trends in incidence rates and the female-to-male ratio of PBC patients and specific sex and geographic impacts on the incidence rates and outcomes of PBC demand further investigation.

Geographical region and clinical outcomes of patients with primary biliary cholangitis from Western Europe

BACKGROUND AND AIMS

The are geographic variations in the incidence and prevalence of primary biliary cholangitis (PBC). The aim was to explore whether clinical outcomes of patients within Western Europe differ according to geographical region.

METHODS

Ursodeoxycholic acid-treated patients from European centers from the Global PBC database diagnosed from 1990 onwards were included. Patients with a time lag > 1 year from diagnosis to start of follow-up were excluded. Differences in baseline characteristics were studied according to North/South and East/West, whereas outcomes (transplant-free survival and decompensation) were studied with center latitude and longitude. Cox regression analyses were adjusted for age, sex, diagnosis year, biochemical markers, and cirrhosis as a time-dependent covariate.

RESULTS

One thousand eight hundred seventy-eight patients were included, and there were no geographical differences in age or sex, with a mean age of 54 years and 89% female patients. Those in North Europe were more often of a moderately advanced/advanced Rotterdam biochemical stage (28.4%) compared with South Europe (20.6%). Additionally, they exhibited higher median alkaline phosphatase (2.0 ×ULN vs. 1.4 ×ULN) and transaminases. In multivariable analysis, there was a significant interaction between center latitude and longitude for decompensation (P < 0.001) and a trend for transplant-free survival, in which the Northwestern area demonstrated an increased risk for poor outcomes as compared to the reference (Paris).

CONCLUSION

We describe geographic variations in outcomes for patients across Europe from specialist centers in the Global PBC Study Group. Further study is important to explore the potential individual, environmental, and healthcare-related factors that may be contributors.

Immunologic Responses and the Pathophysiology of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease with a female predisposition and selective destruction of intrahepatic small bile ducts leading to nonsuppurative destructive cholangitis. It is characterized by seropositivity of antimitochondrial antibodies or PBC-specific antinuclear antibodies, progressive cholestasis, and typical liver histologic manifestations. Destruction of the protective bicarbonate-rich umbrella is attributed to the decreased expression of membrane transporters in biliary epithelial cells (BECs), leading to the accumulation of hydrophobic bile acids and sensitizing BECs to apoptosis. A recent X-wide association study reveals a novel risk locus on the X chromosome, which reiterates the importance of Treg cells.

Contemporary Epidemiology of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a cholestatic liver disease with potential evolution to liver cirrhosis when left untreated. Despite being rare, PBC has a substantial impact on the quality of life and survival of affected patients. Women are the most diagnosed worldwide; however, male subjects seem to have more aggressive disease and worse prognosis. Changing epidemiologic trends are emerging in PBC, with increasing global prevalence and slight smoothing of sex differences. In this review we present available data on incidence rates and prevalence of PBC worldwide, highlighting geographic differences and factors impacting clinical outcomes.

Optimization of Laboratory Diagnostics of Primary Biliary Cholangitis: When Solid-Phase Assays and Immunofluorescence Combine

The laboratory diagnostics of primary biliary cholangitis (PBC) have substantially improved, thanks to innovative analytical opportunities, such as enzyme-linked immunosorbent assays (ELISA) and multiple immunodot liver profile tests, based on recombinant or purified antigens. This study aimed to identify the best diagnostic test combination to optimize PBC diagnosis. Between January 2014 and March 2017, 164 PBC patients were recruited at the hospitals of Parma, Modena, Reggio-Emilia, and Piacenza. Antinuclear antibodies (ANA) and anti-mitochondrial antibodies (AMA) were assayed by indirect immunofluorescence (IIF), ELISA, and immunodot assays (PBC Screen, MIT3, M2, gp210, and sp100). AMA-IIF resulted in 89.6% positive cases. Using multiple immunodot liver profiles, AMA-M2 sensitivity was 94.5%, while anti-gp210 and anti-sp100 antibodies were positive in 16.5% and 17.7% of patients, respectively. PBC screening yielded positive results in 94.5% of cases; MIT3, sp100, and gp210 were detected by individual ELISA test in 89.0%, 17.1%, and 18.9% of patients, respectively. The association of PBC screening with IIF-AMA improved the diagnostic sensitivity from 89.6% to 98.2% (p < 0.01). When multiple immunodot liver profile testing was integrated with AMA-IIF, the diagnostic sensitivity increased from 89.1% to 98.8% (p < 0.01). The combination of IIF with solid-phase methods significantly improved diagnostic efficacy in PBC patients.

The Role of Epigenetics in Primary Biliary Cholangitis

Primary Biliary Cholangitis (PBC) is a rare autoimmune disease of the liver, affecting mostly females. There is evidence that epigenetic changes have a pathogenic role in PBC. Epigenetic modifications are related to methylation of CpG DNA islands, post-translational modifications of histone proteins, and non-coding RNAs. In PBC, there are data showing a dysregulation of all these levels, especially in immune cells. In addition, epigenetics seems to be involved in complex phenomena such as X monosomy or abnormalities in the process of X chromosome inactivation, which have been reported in PBC and appear to influence its sex imbalance and pathogenesis. We review here historical data on epigenetic modifications in PBC, present new data, and discuss possible links among X-chromosome abnormalities at a genetic and epigenetic level, PBC pathogenesis, and PBC sex imbalance.

The Epidemiology of UK Autoimmune Liver Disease Varies With Geographic Latitude

BACKGROUND & AIMS

The epidemiology of autoimmune liver disease (AILD) is challenging to study because of the diseases' rarity and because of cohort selection bias. Increased incidence farther from the Equator has been reported for multiple sclerosis, another autoimmune disease. We assessed the incidence of primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and autoimmune hepatitis (AIH) in relation to latitude.

METHODS

We performed a retrospective cohort study using anonymized UK primary care records from January 1, 2002, to May 10, 2016. All adults without a baseline diagnosis of AILD were included and followed up until the first occurrence of an AILD diagnosis, death, or they left the database. Latitude was measured as registered general practice rounded down to whole degrees.

RESULTS

The cohort included 8,590,421 records with 53.3 × 10⁷ years of follow-up evaluation from 694 practices. There were 1314 incident cases of PBC, 396 of PSC, and 1034 of AIH. Crude incidences were as follows: PBC, 2.47 (95% CI, 2.34-2.60); PSC, 0.74 (95% CI, 0.67-0.82); and AIH, 1.94 (95% CI, 1.83-2.06) per 100,000 per year. PBC incidence correlated with female sex, smoking, and deprivation; PSC incidence correlated with male sex and non-smoking; AIH incidence correlated with female sex and deprivation. A more northerly latitude was associated strongly with incidence of PBC: 2.16 (95% CI, 1.79-2.60) to 4.86 (95% CI, 3.93-6.00) from 50°N to 57°N (P = .002) and incidence of AIH: 2.00 (95% CI, 1.65-2.43) to 3.28 (95% CI, 2.53-4.24) (P = .003), but not incidence of PSC: 0.82 (95% CI, 0.60-1.11) to 1.02 (95% CI, 0.64-1.61) (P = .473). Incidence after adjustment for age, sex, smoking, and deprivation status showed similar positive correlations for PBC and AIH with latitude, but not PSC. Incident AIH cases were younger at more northerly latitude.

CONCLUSIONS

We describe an association in the United Kingdom between more northerly latitude and the incidence of PBC and AIH that requires both confirmation and explanation.

Recent advances in clinical practice: epidemiology of autoimmune liver diseases

Autoimmune liver diseases are chronic inflammatory hepatobiliary disorders that when classically defined encompass three distinctive clinical presentations; primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH). Meaningful changes in disease epidemiology are reported, with increasing incidence and prevalence of AIH and PSC in Europe, and rising prevalence of PBC across Europe, North America and the Asia-Pacific region. However, there appears to be very significant global variation with contemporary incidence rates of disease per 100 000 ranging from 0.84 to 2.75 for PBC, 0.1 to 4.39 for PSC and 0.4 to 2.39 for AIH. Prevalence corresponds, and per 100 000 estimates for PBC range from 1.91 to 40.2, for PSC between 0.78 and 31.7 and for AIH from 4.8 to 42.9. Population-based studies and multicentre observational cohort series provide improved understanding of the clinical course that patients experience, highlighting variations in presenting phenotypes geographically and temporally. Collectively, while autoimmune liver diseases are rare, the clinical burden is disproportionately high relative to population incidence and prevalence. Age, sex and race also impact clinical outcomes, and patient morbidity and mortality are reflected by high need for gastroenterology, hepatology and organ transplant services.

The Epidemiology of Primary Biliary Cholangitis in European Countries: A Systematic Review and Meta-Analysis

BACKGROUND

Primary biliary cholangitis (PBC) is a chronic autoimmune cholestatic liver disease with wide ranges of reported incidence and prevalence.

AIM

To map the incidence and prevalence of PBC in European countries from 2000 through 2020.

METHODS

Following PRISMA recommendations, we searched the Medline and Scopus databases for studies with information on either the incidence or prevalence of PBC. After data extraction, we used a random-effects model to estimate both the pooled annual incidence rate and pooled point-prevalence rate and performed subgroup analyses to identify components contributing to between-study heterogeneity.

RESULTS

We performed a qualitative and quantitative analysis of 18 studies. The pooled point-prevalence rate was 22.27 cases per 100,000 inhabitants (95% CI: 17.98-27.01), and the pooled annual incidence rate was 1.87 new cases per 100,000 inhabitants (95% CI: 1.46-2.34). In the subgroup analyses, we proved that a small part of the between-study heterogeneity is significantly associated with a history of being part of the Eastern Bloc.

Regional variation and temporal trend of primary biliary cholangitis epidemiology: A systematic review and meta-analysis

BACKGROUND AND AIM

We aimed to estimate the worldwide incidence and prevalence, with focus on the geographical differences and temporal trends.

METHODS

Studies on epidemiology of primary biliary cholangitis (PBC) in PubMed, Embase, and Cochrane Library were systematically retrieved from inception to October 2, 2020. Random-effect model was applied to estimate the pooled PBC incidence and prevalence rates. Subgroup analysis, meta-regression, and sensitivity analysis were conducted to find out the cause for heterogeneity.

RESULTS

Out of 3974 records identified through database searching, 47 population-based studies were finally included. The pooled global incidence and prevalence of PBC were 1.76 and 14.60 per 100 000 persons, respectively. Both the PBC incidence and prevalence were lower in the Asia-Pacific region (0.84, 9.82 per 100 000 persons) than that in North America (2.75, 21.81 per 100 000 persons) and Europe (1.86, 14.59 per 100 000 persons) (P < 0.05). The incidence and prevalence showed an increasing tendency in all three regions, with the fastest growth of prevalence in North America (P < 0.05). We found a similar incidence and a lower prevalence of PBC in Northern Europe than that in Southern Europe. A higher incidence and prevalence were observed in female individuals and in the elderly (60-79).

CONCLUSION

The PBC incidence and prevalence varied widely across regions, with North America being the highest, followed by Europe, and the lowest in the Asia-Pacific region. Both the incidence and prevalence showed an increasing tendency worldwide, especially in North America.

Identification of the Representative Primary Biliary Cholangitis Cohort in Taiwan: A Comparison of Four Nationwide Cohorts

BACKGROUND/PURPOSE

The rates and outcomes of primary biliary cholangitis (PBC) in Taiwan remain unclear.

METHODS

A nationwide population-based cohort study (Taiwan National Health Insurance Research Database, 2002-2015) was conducted. Data from four PBC cohorts with various definitions were compared (cohort 1 (C1): ICD-9-CM (571.6); C2: alkaline phosphatase (Alk-P) and antimitochondrial antibody (AMA) measurements; C3: Alk-p and AMA measurements and ursodeoxycholic acid (UDCA) treatment; C4: ICD-9-CM (571.6), Alk-p and AMA measurements and UDCA treatment).

RESULTS

The average prevalence rate ranged from 9.419/10⁵ (C4) to 307.658/10⁵ (C2), and the female-to-male ratio ranged from 1.192 (C1) to 3.66 (C4). Prevalence rates increased over time in all cohorts. The average incidence rates ranged from 1.456/10⁵ (C4) to 66.386/10⁵ (C2). Incidence rates decreased over time in C1 (-9.09%, p < 0.0001) and C4 (-6.68%, p < 0.0001) and remained steady in the others. C4 had the lowest prevalence and incidence rates and highest female-to-male ratio. Cirrhosis rates ranged from 7.21% (C2) to 39.34% (C4), hepatoma rates ranged from 2.77%(C2) to 6.66%(C1), liver transplantation (LT) rates ranged from 1.07% (C2) to 6.77% (C4), and mortality rates ranged from 18.24% (C2) to 47.36% (C1). C4 had the highest LT (6.77%), osteoporosis (13.87%) and dyslipidemia rates (17.21%).

CONCLUSIONS

Based on the reported ranges of reasonable rates, female predominance and characteristic outcomes, C4 was the most representative Taiwanese PBC cohort, with average prevalence and incidence rates of 9.419/10⁵ and 1.456/10⁵, respectively, and a female-to-male ratio of 3.66. In a 14-year period, cirrhosis, hepatoma, LT, and mortality were noted in 39.34%, 5.52%, 6.77%, and 34.22% of C4 patients, respectively.

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.

Geo-epidemiology and environmental co-variate mapping of primary biliary cholangitis and primary sclerosing cholangitis

Background & Aims

Autoimmune liver disease (AILD) is thought to result from a complex interplay between genetics and the environment. Studies to date have focussed on primary biliary cholangitis (PBC) and demonstrated higher disease prevalence in more urban, polluted, and socially deprived areas. This study utilises a large cohort of patients with PBC and primary sclerosing cholangitis (PSC) to investigate potential environmental contributors to disease and to explore whether the geo-epidemiology of PBC and PSC are disease-specific or pertain to cholestatic AILD in general.

Methods

All adult patients with PBC and PSC in a tightly defined geographical area within the UK were identified. Point- and area-based analyses and structural equation modelling (SEM) were used to investigate for disease clustering and examine for relationships between prevalence, distribution of environmental contaminants, and socio-economic status.

Results

We identified 2,150 patients with PBC and 472 with PSC. Significant spatial clustering was seen for each disease. A high prevalence of PBC was found in urban, post-industrial areas with a strong coal-mining heritage and increased environmental cadmium levels, whereas a high PSC prevalence was found in rural areas and inversely associated with social deprivation.

Conclusions

This study demonstrates spatial clustering of PBC and PSC and adds to our understanding of potential environmental co-variates for both diseases. Disease clustering, within the same geographical area but over different scales, is confirmed for each disease with distinct risk profiles identified and associations with separate putative environmental factors and socio-economic status. This suggests that different triggers and alternative pathways determine phenotypic expression of autoimmunity in the affected population. Co-variate analysis points towards the existence of specific disease triggers.

Lay summary

This study looked for potential environmental triggers in patients with primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) living in the north-east of England and north Cumbria. We found that PBC was more common in urban areas with a history of coal mining and high levels of cadmium whereas PSC was more common in rural areas with lower levels of social deprivation.

•

Clustering of PBC and PSC patients occurs with notable geographical differences.

•

A high prevalence of PBC is seen in urban, post-industrial areas.

•

PSC is more common in rural areas and inversely associated with social deprivation.

•

PBC risk is associated with proximity to coal mines and environmental cadmium levels.

•

Comprehensive epidemiological study can increase understanding of disease aetiology.

Review article: pathophysiology and management of primary biliary cholangitis

BACKGROUND

Primary biliary cholangitis (PBC), an immune-mediated disease characterised by destruction of intrahepatic bile ducts, results in progressive damage to the biliary tree, cholestasis and ultimately advanced liver disease. In the last decade, advances in practice have improved clinical care, driven novel therapeutic options and improved risk stratification tools.

AIMS

To provide an overview of the disease characteristics of PBC and review a patient-centred management approach for the clinical team caring for those with PBC.

METHODS

We reviewed the current literature and guidelines on PBC with a focus on management and therapies.

RESULTS

A confident diagnosis of PBC is usually made based on serum liver tests and immune serology. Management of PBC should focus on three main 'process' pillars: (a) treat and risk-stratify through use of biochemical and prognostic criteria; (b) manage concurrent symptoms and other associated diseases; and (c) stage disease, monitor progression and prevent complications. With ongoing complexities in management, including a newly licensed therapy (obeticholic acid) and alternative non-licensed treatments and ongoing clinical trials, discussion with PBC expert centres is encouraged.

CONCLUSIONS

PBC is a dynamic disease wherein current treatment goals have become appropriately ambitious. Goals of care should prioritise prevention of end-stage liver disease and amelioration of patient symptom burden for all.

Clinical Updates in Primary Biliary Cholangitis: Trends, Epidemiology, Diagnostics, and New Therapeutic Approaches

Primary biliary cholangitis, formerly known as primary biliary cirrhosis, is a chronic, autoimmune, and cholestatic disease ameliorating the biliary epithelial system causing fibrosis and end-stage liver disease, over time. Patients range from an asymptomatic phase early in the disease course, to symptoms of decompensated cirrhosis later in its course. This review focuses on the current consensus on the epidemiology, diagnosis, and management of patients with primary biliary cholangitis. We also discuss established medical management as well as novel and investigational therapeutics in the pipeline for management of PBC.

Race/Ethnicity and Insurance-Specific Disparities in In-Hospital Mortality Among Adults with Primary Biliary Cholangitis: Analysis of 2007-2014 National Inpatient Sample

BACKGROUND

Primary biliary cholangitis (PBC) is a progressive autoimmune liver disease that can result in cirrhosis and end-stage liver disease.

AIMS

We aim to evaluate hospitalization burden and in-hospital mortality among PBC patients in the USA.

METHODS

Using data from the Nationwide Inpatient Sample from 2007 to 2014, hospitalizations among US adults with PBC were stratified by sex, age, and race/ethnicity. Overall in-hospital mortality was stratified by these variables and adjusted multivariate regression models evaluated for predictors of in-hospital mortality.

RESULTS

From 2007 to 2014, there were 18,279 hospitalizations among adults with PBC (15.0% male, mean age 63.8 years, 41.3% cirrhosis). Among non-Hispanic whites, the proportion of total PBC hospitalizations increased from 57.8% in 2007 to 71.2% in 2014, compared to 4.1-6.3% for African-Americans, 8.6-10.9% for Hispanics, and 1.7-2.8% for Asians (p < 0.001 for all). While overall in-hospital mortality was low (4.2%), increasing age was associated with higher odds of in-hospital mortality (OR: 1.02, 95% CI 1.01-1.03, p < 0.001). Compared to non-Hispanic white PBC patients, higher in-hospital mortality was observed in African-American PBC patients (OR: 1.40, 95% CI 1.16-2.03, p < 0.05). Compared to patients with private/commercial insurance, significantly higher odds of in-hospital mortality were observed in patients with Medicaid insurance (OR 1.42, 95% CI 1.00-1.99, p < 0.05).

CONCLUSION

In summary, among adults with PBC hospitalized in the USA from 2007 to 2014, the overall number of hospitalizations is increasing. Significant disparities in in-hospital mortality were observed; African-Americans with PBC and Medicaid patients with PBC have disproportionately higher odds of in-hospital mortality.

The toxicity of the methylimidazolium ionic liquids, with a focus on M8OI and hepatic effects

Ionic liquids are a diverse range of charged chemicals with low volatility and often liquids at ambient temperatures. This characteristic has in part lead to them being considered environmentally-friendly replacements for existing volatile solvents. However, methylimidazolium ionic liquids are slow to break down in the environment and a recent study at Newcastle detected 1 octyl 3 methylimidazolium (M8OI) - an 8 carbon variant methylimidazolium ionic liquid - in soils in close proximity to a landfill site. The current M8OI toxicity database in cultured mammalian cells, in experimental animal studies and in model indicators of environmental impact are reviewed. Selected analytical data from the Newcastle study suggest the soils in close proximity to the landfill site, an urban soil lacking overt contamination, had variable levels of M8OI. The potential for M8OI - or a structurally related ionic liquid - to trigger primary biliary cholangitis (PBC), an autoimmune liver disease thought to be triggered by an unknown agent(s) in the environment, is reviewed.

Epidemiological and clinical features of primary biliary cholangitis in two Croatian regions: a retrospective study

AIM

To assess the measures of disease frequency and determine the clinical features of primary biliary cholangitis (PBC) in two Croatian regions.

METHODS

Databases of two tertiary hospitals, one located in the continental and one in the coastal region of Croatia, were retrospectively searched for PBC patients diagnosed from 2007 to 2018. Epidemiologic data analysis was restricted to patients from each hospital's catchment area. We analyzed factors related to response to therapy and event-free survival (EFS), defined as absence of ascites, variceal bleeding, encephalopathy, hepatocellular carcinoma, liver transplantation (LT), or death. In addition, we determined clinical and demographic data of transplanted PBC patients.

RESULTS

Out of 83 PBC patients, 86.7% were female, with a median age at diagnosis of 55 years. Average PBC incidence for the 11-year period was 0.79 and 0.89 per 100000 population, whereas the point prevalence on December 31, 2017 was 11.5 and 12.5 in the continental and coastal region, respectively. Of 76 patients with complete medical records, 21% had an advanced disease stage, 31.6% had an associated autoimmune condition, and all received ursodeoxycholic acid. EFS rate at 5 years was 95.8%. In an age and sex-adjusted multivariate Cox regression model, the only factor significantly associated with inferior EFS was no response to therapy (HR=18.4; P=0.018). Of all Croatian patients who underwent LT, 3.8% had PBC, with the survival rate at 5 years after LT of 93.4%.

CONCLUSION

This study gives pioneer insights into the epidemiological and clinical data on PBC in Croatia, thus complementing the PBC map of Southeast Europe.

Increase trend in the prevalence and male-to-female ratio of primary biliary cholangitis, autoimmune hepatitis, and primary sclerosing cholangitis in Japan

AIM

Autoimmune liver diseases (AILD) including autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) impose a significant burden on public health, and it is important to estimate their prevalence. We carried out a nationwide, hospital-based, epidemiological survey of AIH, PBC, and PSC, and compared the results with those from previous surveys.

METHOD

We randomly selected health-care facilities used in the survey from a list of all facilities in Japan. The selection rate was determined according to a stratification based on the facility characteristics and scale. We sent questionnaires to the selected facilities enquiring about the number and sex of patients with AILD who visited the facility in 2016. An identical survey was undertaken for AIH/PBC in 2004 and for PSC in 2007; we carried out a comparative analysis of these data.

RESULTS

We selected 1793 departments from health centers all over Japan. Of them, 1078 (60.1%) responded to the questionnaires. The number of reported patients with AIH, PBC, and PSC was 8505, 10 847, and 906, respectively, and point prevalence was 23.9 (95% confidence interval, 23.3-24.5) for AIH (8.7 in 2004), 33.8 (33.0-34.6) for PBC (11.6 in 2004), and 1.80 (1.75-1.85) for PSC (0.95 in 2007) per 100 000 population. Male-to-female patient ratio of AILD was 1:4.3 for AIH (1:6.9 in 2004), 1:3.9 for PBC (1:7.1 in 2004), and 1:0.88 for PSC (1:1.4 in 2007).

CONCLUSION

The current study indicates an increasing trend of prevalence as well as male-to-female patient ratio of AILD in Japan.

Guideline review: British Society of Gastroenterology/UK-PBC Primary Biliary Cholangitis treatment and management guidelines

New guidelines have been produced for the management of primary biliary cholangitis, an infrequent but nonetheless important autoimmune liver disease. We provide a succient commentary and overview of the key features of disease management that arise from these recent guideline recommendations, with a focus on therapy with licensed agents (ursodeoxycholic acid and obeticholic acid) as well as personalised management of disease complications and associated symptoms.

The genetics of primary biliary cholangitis

PURPOSE OF REVIEW

Primary biliary cholangitis (PBC) is a female predominant chronic autoimmune disease of the intrahepatic bile ducts and with a long latent period. It is crucial to understand how genetics contribute to the disease.

RECENT FINDINGS

Geo-epidemiological studies in PBC have provided evidence of familial risk; case-control studies and genome wide association studies have identified various human leukocyte antigen (HLA) and non-HLA alleles that are associated with PBC. However, these alleles are non-PBC specific and most of the identified non-HLA loci were also found to be susceptible genes in other autoimmune diseases and different between study populations.

SUMMARY

Patients with PBC are often asymptomatic and often left undiagnosed. There are no known HLA and non-HLA alleles specific for PBC. Global effort and novel approaches such as epigenetics directed at identification of genetic risk factors will greatly facilitate accurate and timely diagnosis, which will improve prognosis and increase treatment options.

Pathogen infections and primary biliary cholangitis

Primary biliary cholangitis (PBC) is a multi-factorial disease caused by the interaction of both genetic predisposition and environmental triggers. Bacterial infection has been investigated most intensively, both epidemiologically and experimentally, as a prime environmental aetiology in PBC. The association of recurrent history of urinary tract infection (UTI) with PBC has been frequently confirmed by several large-scale, case-control studies, despite variation in geographic area or case-finding methods. Escherichia coli is a predominant pathogen in most cases with UTI. Animal studies and molecular mimicry analysis between the human and E. coli E2 subunit of the 2-oxo-acid dehydrogenase complexes demonstrated that E. coli infection is a key factor in breaking immunological tolerance against the mitochondria, resulting in the production of anti-mitochondrial autoantibodies (AMA), the disease-specific autoantibodies of PBC. Novosphingobium aromaticivorans, a ubiquitous xenobiotic-metabolizing bacterium, is another candidate which may be involved in the aetiology of PBC. Meanwhile, improved environmental hygiene and increased prevalence of PBC, especially in males, may argue against the aetiological role of bacterial infection in PBC. Multiple mechanisms can result in the loss of tolerance to mitochondrial autoantigens in PBC; nonetheless, bacterial infection is probably one of the dominant pathways, especially in female patients. Notably, there is a rising prevalence of male patients with PBC. With increasing exposure to environmental xenobiotics in both genders, studies directed towards identifying the environmental culprit with systematically designed case-control studies are much needed to further determine the environmental factors and role of bacterial infections in PBC.

Primary biliary cholangitis with contemporary presence of anti-mithocondrial and anti-rods and rings autoantibodies: literature first case

Primary biliary cholangitis, previously known as primary biliary cirrhosis (PBC), is the most common autoimmune diseases of the liver (ALD). Patients with PBC may present with typical biliary pattern symptoms. Also the presence of anti-mitochondrial autoantibodies (AMAs) is the laboratory hallmark of PBC, which molecular target antigens are members of 2-oxoacid dehydrogenase complex of enzymes. In recent years, autoantibodies (Aab) targeting subcellular structures described as the rods and rings (R&R) pattern in HEp-2 ANA have been presented as a unique and particular case of Aab generation. These R&R structures are composed of inosine monophosphate dehydrogenase type 2 (IMPDH2), and their formation can be induced in vitro by several small-molecule inhibitors. Aab targeting these relatively unknown structures have been almost exclusively observed in hepatitis C virus (HCV) patients who have undergone treatment with pegylated interferon-a/ribavirin (IFN/RBV) therapy. Literature showed that anti-RR Aab have not been found in no treatment-naïve HCV patients or in patients from any other disease. Now we present and characterized a case patient with contemporary presence of AMAs and R&R Aab in PBC, without any laboratory evidence of HCV and/or other hepatic virus infection. For our knowledge, this is the first case described in the Literature. R&R Aab in patients without any clinical/laboratory signs or symptoms of Hepatitis virus and without pharmacological therapy open the window to the alternative scenario: the association of these Aab to ALD. Our work demonstrated that R&R Aab can be present in PBC case. The interesting idea suggested that R&R Aab may be present also in AMA-negative PBC and they can considered a new possible diagnostic tool in this specific clinical condition. Other study and cases are needed but the presence of R&R Aab linked with AMAs and PBC may be explained by alterations in immune regulation caused by autoimmunity in a particular genetic background.

Epidemiology and liver transplantation burden of primary biliary cholangitis: a retrospective cohort study

BACKGROUND

There is a wealth of data documenting the epidemiology of primary biliary cholangitis (PBC) globally; however, the epidemiology of PBC has not been as well studied in Canada. Our study characterized the Canadian prevalence of PBC and the number of liver transplantations because of PBC.

METHODS

For this retrospective cohort study we used national hospital administrative records from the Canadian Institute for Health Information, with the exception of Quebec for the prevalence estimate and Quebec and British Columbia for the transplant analysis. Prevalent patients were identified through a diagnostic code for PBC of the Canadian version of the 10th revision of the International Classification of Diseases. PBC transplant patients were identified from their transplant record. Descriptive statistics were used to summarize the characteristics of the study cohorts.

RESULTS

In 2015, 8680 patients with PBC were identified in Canada, translating to a prevalence of 318 cases per million. Annual prevalence by province varied, ranging from 283 (95% confidence interval [CI] 269-297) cases per million to 465 (95% CI 426-504) cases per million, and the 6-year PBC liver transplantation rate ranged from 3.17 (95% CI 1.27-6.54) to 5.92 (95% CI 3.71-9.08) per million. The Atlantic provinces exhibited the highest PBC prevalence and close to the highest 6-year liver transplantation rate (465 [95% CI 426-504] cases per million and 5.70 [95% CI 426-504, 3.19-9.56] cases per million, respectively). We observed the lowest PBC prevalence (283 [95% CI 269-297] cases per million) and the second lowest 6-year liver transplantation rate in Ontario (3.37 [95% CI 2.47-4.50] cases per million).

INTERPRETATION

The prevalence of PBC that we found in Canada is similar to the prevalence reported in other studies, but our work also indicates geographic variation within this country. Given our finding of geographic clustering of PBC across Canada, we hypothesize that environmental and genetic factors contribute to the pathogenesis of this condition.

Primary biliary cholangitis

Primary cholangitis (cirrhosis) is a chronic cholestatic disease with an unquestionable female predominance. It is characterised by inflammation of the small and medium size bile ducts, and can eventually progress to cirrhosis. Most patients remain asymptomatic and are diagnosed by the casual finding of an anicteric biochemical cholestasis with increased alkaline phosphatase. The pathogenesis is unknown and of presumed autoimmune origin in genetic susceptible subjects. M2-type antimitochondrial antibodies, and specific antinuclear antibodies (gp210 and Sp100) are typical and specific of the disease. The positivity of these antibodies and a biochemical cholestasis are sufficient for diagnosis, without the need for liver biopsy. Ursodeoxycholic acid is the specific treatment with an excellent response in more than 60% of patients. When this optimal response is not observed, it can be combined with new agents, but those that have shown to be effective are those that improve cholestasis such as fibrates and obeticholic acid.

The British Society of Gastroenterology/UK-PBC primary biliary cholangitis treatment and management guidelines

Primary biliary cholangitis (formerly known as primary biliary cirrhosis, PBC) is an autoimmune liver disease in which a cycle of immune mediated biliary epithelial cell injury, cholestasis and progressive fibrosis can culminate over time in an end-stage biliary cirrhosis. Both genetic and environmental influences are presumed relevant to disease initiation. PBC is most prevalent in women and those over the age of 50, but a spectrum of disease is recognised in adult patients globally; male sex, younger age at onset (<45) and advanced disease at presentation are baseline predictors of poorer outcome. As the disease is increasingly diagnosed through the combination of cholestatic serum liver tests and the presence of antimitochondrial antibodies, most presenting patients are not cirrhotic and the term cholangitis is more accurate. Disease course is frequently accompanied by symptoms that can be burdensome for patients, and management of patients with PBC must address, in a life-long manner, both disease progression and symptom burden. Licensed therapies include ursodeoxycholic acid (UDCA) and obeticholic acid (OCA), alongside experimental new and re-purposed agents. Disease management focuses on initiation of UDCA for all patients and risk stratification based on baseline and on-treatment factors, including in particular the response to treatment. Those intolerant of treatment with UDCA or those with high-risk disease as evidenced by UDCA treatment failure (frequently reflected in trial and clinical practice as an alkaline phosphatase >1.67 × upper limit of normal and/or elevated bilirubin) should be considered for second-line therapy, of which OCA is the only currently licensed National Institute for Health and Care Excellence recommended agent. Follow-up of patients is life-long and must address treatment of the disease and management of associated symptoms.

Geoepidemiology of Primary Biliary Cholangitis: Lessons from Switzerland

No data on primary biliary cholangitis (PBC) are available in Switzerland. We established a national patient cohort to obtain information on PBC phenotypes and disease course in Switzerland. Local databases in all university hospitals and in two large secondary centers were searched for case finding. In addition, all primary care physicians, gastroenterologists, rheumatologists, and dermatologists were invited to contribute patients from their own medical records. PBC diagnosis was centrally reviewed. Five hundred one PBC patients were identified, 474 were included in data analysis, and 449 of them were enrolled by tertiary centers. The catchment area accounts for approximately one third of the Swiss population or approximately 2.8 million inhabitants. The median age at diagnosis was 53 years, 84% were women, and 86% were anti-mitochondrial antibody positive. The median follow-up was 5.4 years, 12.6% experienced a liver-related endpoint. Splenomegaly was present at diagnosis in one quarter of patients and in half of male patients. Approximately one third were non-responders to ursodeoxycholic acid (UDCA). The median transplant-free survival at 10 years was 85%. The following variables were independently associated with poor outcome: low platelet count at baseline (HR = 0.99, p < 0.0001), elevated alkaline phosphatase at baseline (HR = 1.36, p < 0.0001), elevated bilirubin at baseline (HR = 1.11, p = 0.001), and elevated alanine aminotransaminase (HR = 1.35, p = 0.04) after 12 months of UDCA therapy. The AUROC for the UK-PBC risk score at 5, 10, and 15 years was 0.82. The AUROC for the Globe score at 5, 10, and 15 years was 0.77. Patients included in this study are currently being enrolled in a prospective nationwide registry with biobank, taking advantage of the collaboration network generated by this study. Our study provides the first snapshot of PBC in Switzerland, describing a diagnostic delay with one quarter of patients diagnosed when already in the cirrhotic stage. We were also able to externally validate the UK-PBC risk score and the Globe score. The ongoing nationwide prospective registry will be fundamental to improve disease awareness and interdisciplinary collaborations and will serve as a platform for clinical and translational research.

TRIAL REGISTRATION NUMBER

clinicaltrials.gov : NCT02846896; SNCTP000001870.

The Genetics and Epigenetics of Primary Biliary Cholangitis

Both genetic background and environmental factors contribute to primary biliary cholangitis (PBC). Recent innovative technologies, such as genome-wide association studies, identified a remarkable number of susceptible nonhuman leukocyte antigen genes contributing to the development of PBC; however, they are primarily indicators of active immunologic responses commonly involved in autoimmune reactions. Thus, recent studies have focused on epigenetic mechanisms that would link genetic predisposition and environmental triggering factors. In PBC, methylation profiling and altered X chromosome architecture have been intensively explored in conjunction with a striking female predominance. Further, microRNAs have been found to be associated with the etiology of PBC.

Evolution of our understanding of PBC

The discovery of mitochondrial autoantigens recognized by antimitochondrial antibodies (AMAs) in 1987 marked the dawn of a new era in primary biliary cholangitis (PBC) research. Since then, there has been substantial progress in our understanding of PBC partly bestowed by the development of innovative technologies in molecular biology, immunology, and genetics. Here, we review this evolutionary progress in understanding PBC. We now recognize that the epitopes of AMAs, CD4⁺, and CD8⁺ T cells are all mapped to the same region of the inner lipoyl domain of pyruvate dehydrogenase complex E2 subunit (PDC-E2), and that intrahepatic biliary epithelial cells (BECs) are exclusively targeted in PBC. BECs express PDC-E2 on apotopes in an immunologically intact form during apoptosis, but not other epithelial cells, which could explain the tissue specificity of PBC. In addition, genetic factors, environmental triggers, and epigenetic modifications play crucial roles in the development of PBC. Intact lipoylated PDC-E2, presumably after modification with xenobiotics such as 2-octynamide or 2-nonyamide that are abundantly present in the environment, is endocytosed by antigen-presenting cells and are presented to CD4⁺ or CD8⁺ T cells. An immune complex consisting of PDC-E2 and anti-PDC-E2 autoantibodies cross-present autoantigens in a more efficient manner. Finally, an adenylate uridine-rich element (ARE) Del -/- mouse model has been established, which presents a disease modeling human PBC, including female dominance as one of its most important features, and can be used to dissect the immunopathology of PBC. Expanding our knowledge of the pathology from a very early stage of the disease will provide the key to cure PBC.

Milder disease stage in patients with primary biliary cholangitis over a 44-year period: A changing natural history

Changes over time in the presenting features and clinical course of patients with primary biliary cholangitis are poorly described. We sought to describe temporal trends in patient and disease characteristics over a 44-year period across a large international primary biliary cholangitis cohort of 4,805 patients diagnosed between 1970 and 2014, from 17 centers across Europe and North America. Patients were divided into five cohorts according to their year of diagnosis: 1970-1979 (n = 143), 1980-1989 (n = 858), 1990-1999 (n = 1,754), 2000-2009 (n = 1,815), and ≥2010 (n = 235). Age at diagnosis, disease stage, response to ursodeoxycholic acid, and clinical outcomes were compared. Mean age at diagnosis increased incrementally by 2-3 years per decade from 46.9 ± 10.1 years in the 1970s to 57.0 ± 12.1 years from 2010 onward (P < 0.001). The female to male ratio (9:1) and antimitochondrial antibody positivity (90%) were not significantly variable. The proportion of patients presenting with mild biochemical disease (according to Rotterdam staging) increased from 41.3% in the 1970s to 72.2% in the 1990s (P < 0.001) and remained relatively stable thereafter. Patients with a mild histological stage at diagnosis increased from 60.4% (1970-1989) to 76.5% (1990-2014) (P < 0.001). Correspondingly, response to ursodeoxycholic acid according to Paris-I criteria increased; 51.7% in the 1970s and 70.5% in the 1990s (P < 0.001). Recent decades were also characterized by lower decompensation rates (18.5% in the 1970s to 5.8% in the 2000s, P < 0.001) and higher 10-year transplant-free survival (48.4%, 68.7%, 79.7%, and 80.1% for each respective cohort; P < 0.001).

CONCLUSION

In recent decades, a pattern of primary biliary cholangitis presentation consistent with an older age at diagnosis alongside reduced disease severity has been noted; the observed trends may be explained by an increase in routine testing of liver function and/or a changing environmental trigger. (Hepatology 2018;67:1920-1930).

Environmental basis of primary biliary cholangitis

Autoimmunity is a consequence of both genetic and environmental factors, occurring in genetically susceptible hosts with environmental triggers. While genome-wide association studies have revealed a number of susceptible genes contributing to etiology, the environmental triggers remain poorly understood. Primary biliary cholangitis, formally known as primary biliary cirrhosis, is considered a model autoimmune disease for which our group has extensively evaluated environmental factors involved in its etiology. Bacterial infection and xenobiotics have been proposed as candidate environmental factors that may explain tolerance breakdown and production of primary biliary cholangitis-specific antimitochondrial autoantibodies. Large-scale case-control studies have consistently detected an association of primary biliary cholangitis with urinary tract infections caused by Escherichia coli, as E. coli PDC-E2 is molecularly similar to human PDC-E2, the immunodominant target of AMAs. Another bacterium of interest is Novosphingobium aromaticivorans, a ubiquitous xenobiotic-metabolizing bacterium that produces lipoylated proteins, which are highly reactive with sera from primary biliary cholangitis patients. Regarding xenobiotics, case-control studies have suggested that frequent use of nail polish is associated with an increased susceptibility to primary biliary cholangitis. We found that 2-octynamide, the conjugate derived from 2-octynoic acid present in cosmetics, lipsticks, and some chewing gums, was unique in both its quantitative structure-activity relationship analysis and reactivity with primary biliary cholangitis sera. 2-nonyamide is another xenobiotic that also has the optimal chemical structure for xenobiotic modification of the PDC-E2 epitope, as demonstrated by the enhanced epitope recognition with AMA-positive PBC sera. Moreover, we found that C57BL/6 mice immunized with 2-octynoic acid-BSA possess many of the features characteristic to primary biliary cholangitis. Impact statement Autoimmunity is believed to develop in genetically susceptible hosts with triggers from the environment. Researchers have recently demonstrated that bacteria and xenobiotics commonly present in our environment are potential triggers of tolerance breakdown against autoantigens and autoimmunity, particularly in primary biliary cholangitis (PBC). The link between xenobiotics and PBC has been further confirmed with the establishment of PBC model mice by immunizing mice with xenobiotics.

An Update on the Treatment and Follow-up of Patients with Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterized by chronic granulomatous lymphocytic cholangitis of the small bile ducts. PBC was a leading indication for liver transplant in the United States; with early diagnosis and treatment, the majority of patients with PBC have a normal life expectancy. Pathogenesis involves inflammatory damage of bile duct epithelium secondary to innate and adaptive immune responses, and toxicity from accumulated bile acids. Cholestasis and disease progression can lead to cirrhosis. Extrahepatic complications include dyslipidemia, metabolic bone disease, and fat-soluble vitamin deficiency. Ursodeoxycholic acid is a well-established therapy. Novel targeted therapeutics are being developed.

Geoepidemiology, clinical manifestations and outcome of primary biliary cholangitis in Greece

BACKGROUND & AIMS

Primary biliary cholangitis (PBC) is a disease with rising prevalence and considerable geographical variation. To describe the prevalence, spatial and time distribution, baseline characteristics, response to treatment, outcome and the validity of GLOBE score in a large cohort of Greek PBC patients as an independent validation of this score has not been done so far.

METHODS

The last 16years, 482 PBC patients (86.5% females) were evaluated and analysed retrospectively, using a prospectively collected database. Special attention was paid to the assessment of treatment response according to GLOBE score.

RESULTS

Age at initial evaluation was 56.3±13.7years. Among 432 Thessaly residents, prevalence was 582/million (non-homogeneous distribution). Nineteen districts showed a prevalence >800/million. Symptomatic disease onset could be identified in 91 patients, with a significant peak during spring (P=0.03). At diagnosis, 43.6% were asymptomatic and 16.2% cirrhotic. Male sex (P=0.02), older age (P<0.001), alcohol consumption (P<0.01) and concomitant liver disease (P<0.001) were negative prognostic factors for cirrhosis. During a median [interquartile range, range] follow-up of 5.1 (7.8, 15.7) years, 62 patients died or underwent liver transplantation. Patients with GLOBE score>0.30 had significantly worse prognosis (P<0.001) with 5-, 10-, and 15-year survival rates of 84%, 50% and 42%.

CONCLUSIONS

There is increased PBC prevalence in Thessaly with remarkable geographic clustering and seasonal variability. PBC is diagnosed at early stages although males had a more advanced disease. GLOBE score applies perfectly in Greek patients and this will likely help detecting patients that may benefit from new therapies.

Risk and Surveillance of Cancers in Primary Biliary Tract Disease

Primary biliary diseases have been associated in several studies with various malignancies. Understanding the risk and optimizing surveillance strategy of these malignancies in this specific subset of patients are an important facet of clinical care. For instance, primary sclerosing cholangitis is associated with an increased risk for cholangiocarcinoma (which is very challenging to diagnose) and when IBD is present for colorectal cancer. On the other hand, primary biliary cirrhosis patients with cirrhosis or not responding to 12 months of ursodeoxycholic acid therapy are at increased risk of hepatocellular carcinoma. In this review we will discuss in detail the risks and optimal surveillance strategies for patients with primary biliary diseases.

Primary biliary cirrhosis

Primary biliary cirrhosis is a chronic cholestatic liver disease characterised by destruction of small intrahepatic bile ducts, leading to fibrosis and potential cirrhosis through resulting complications. The serological hallmark of primary biliary cirrhosis is the antimitochondrial antibody, a highly disease-specific antibody identified in about 95% of patients with primary biliary cirrhosis. These patients usually have fatigue and pruritus, both of which occur independently of disease severity. The typical course of primary biliary cirrhosis has changed substantially with the introduöction of ursodeoxycholic acid (UDCA). Several randomised placebo-controlled studies have shown that UDCA improves transplant-free survival in primary biliary cirrhosis. However, about 40% of patients do not have a biochemical response to UDCA and would benefit from new therapies. Liver transplantation is a life-saving surgery with excellent outcomes for those with decompensated cirrhosis. Meanwhile, research on nuclear receptor hormones has led to the development of exciting new potential treatments. This Seminar will review the current understanding of the epidemiology, pathogenesis, and natural history of primary biliary cirrhosis, discuss management of the disease and its sequelae, and introduce research on new therapeutic options.

Does primary biliary cirrhosis cluster in time?

The aetiology of primary biliary cirrhosis (PBC) is not well established. Previously we found evidence of space-time clustering and seasonal variation in the date of diagnosis, suggesting a possible role for a transient or seasonally varying environmental factor. We examined whether a temporally varying environmental agent may be involved by analysing population-based PBC data from northeast England over 1987-2003. Using an adaptation of a method proposed by Potthoff and Whittinghill, we found significant temporal variation by date of diagnosis at the level of aggregation of one year. However, there was no evidence for general irregular (non-seasonal) temporal clustering within periods less than a year. These results provide little support for the involvement of agents occurring in geographically widespread mini-epidemics, but--taken together with studies of spatial and spatio-temporal clustering--do not preclude the role of more localised sporadic mini-epidemics. Future research should seek to elicit putative environmental agents.

Spatial analysis of childhood cancer: a case/control study

Background

Childhood cancer was the leading cause of death among children aged 1-14 years for 2012 in Spain. Leukemia has the highest incidence, followed by tumors of the central nervous system (CNS) and lymphomas (Hodgkin lymphoma, HL, and Non-Hodgkin’s lymphoma, NHL). Spatial distribution of childhood cancer cases has been under concern with the aim of identifying potential risk factors.

Objective

The two objectives are to study overall spatial clustering and cluster detection of cases of the three main childhood cancer causes, looking to increase etiological knowledge.

Methods

We ran a case-control study. The cases were children aged 0 to 14 diagnosed with leukemia, lymphomas (HL and NHL) or CNS neoplasm in five Spanish regions for the period 1996-2011. As a control group, we used a sample from the Birth Registry matching every case by year of birth, autonomous region of residence and sex with six controls. We geocoded and validated the address of the cases and controls. For our two objectives we used two different methodologies. For the first, for overall spatial clustering detection, we used the differences of K functions from the spatial point patterns perspective proposed by Diggle and Chetwynd and the second, for cluster detection, we used the spatial scan statistic proposed by Kulldorff with a level for statistical significance of 0.05.

Results

We had 1062 cases of leukemia, 714 cases of CNS, 92 of HL and 246 of NHL. Accordingly we had 6 times the number of controls, 6372 controls for leukemia, 4284 controls for CNS, 552 controls for HL and 1476 controls for NHL. We found variations in the estimated empirical D(s) for the different regions and cancers, including some overall spatial clustering for specific regions and distances. We did not find statistically significant clusters.

Conclusions

The variations in the estimated empirical D(s) for the different regions and cancers could be partially explained by the differences in the spatial distribution of the population; however, according to the literature, we cannot discard environmental hazards or infections agents in the etiology of these cancers.

Testing for clustering at many ranges inflates family-wise error rate (FWE)

BACKGROUND

Testing for clustering at multiple ranges within a single dataset is a common practice in spatial epidemiology. It is not documented whether this approach has an impact on the type 1 error rate.

METHODS

We estimated the family-wise error rate (FWE) for the difference in Ripley's K functions test, when testing at an increasing number of ranges at an alpha-level of 0.05. Case and control locations were generated from a Cox process on a square area the size of the continental US (≈3,000,000 mi2). Two thousand Monte Carlo replicates were used to estimate the FWE with 95% confidence intervals when testing for clustering at one range, as well as 10, 50, and 100 equidistant ranges.

RESULTS

The estimated FWE and 95% confidence intervals when testing 10, 50, and 100 ranges were 0.22 (0.20 - 0.24), 0.34 (0.31 - 0.36), and 0.36 (0.34 - 0.38), respectively.

CONCLUSIONS

Testing for clustering at multiple ranges within a single dataset inflated the FWE above the nominal level of 0.05. Investigators should construct simultaneous critical envelopes (available in spatstat package in R), or use a test statistic that integrates the test statistics from each range, as suggested by the creators of the difference in Ripley's K functions test.