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

Symptom Reporting in Patients with Primary Biliary Cholangitis: Higher Burden of Symptom Detection Using an Interactive App

INTRODUCTION

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease causing bile duct destruction and inflammation, impacting patient's quality of life (QoL) due to variable symptoms. Digital symptom-tracker apps may improve patient care through enhanced monitoring. This study reassessed symptom burden in PBC patients using a tailored symptom-tracker app, focusing on its usability, effectiveness, and impact on management and QoL.

METHODS

Based on Kautz5 gUG "Symptomtracker," our app in REDCap allowed users to log PBC symptoms over 4 weeks, alongside medication use. Ethics approval and data security complied with German regulations. User feedback was incorporated for better usability. Symptom data were standardized, and R software was used for descriptive statistics and Chi-square tests.

RESULTS

From March 2023 to October 2024, 210 patients (190 female, 20 male) were enrolled, median age 51 years. Among 90 patients who completed the questionnaire, fatigue was most prevalent (87.8%), followed by joint pain (80%), concentration difficulties (74.4%), abdominal discomfort (70%), and sicca symptoms. Other common symptoms were leg cramps (50%) and swollen feet (40%); jaundice was rare (7.8%). Older patients, especially those aged 50-60, reported a higher symptom burden, but Chi-square tests showed no significant differences across age or gender.

CONCLUSION

This study highlights a significant symptom burden in PBC, particularly fatigue and joint pain. While older patients reported more symptoms, no significant differences were observed by age or gender. The symptom-tracker app enhanced monitoring and patient engagement, showing the potential of digital tools in PBC management. Further research is needed to evaluate long-term impacts.

Precirrhotic Primary Biliary Cholangitis with Portal Hypertension: Bile Duct Injury Correlate

Background/Aims

The histological characteristics and natural history of precirrhotic primary biliary cholangitis (PBC) with portal hypertension (PH) are unclear. Our aim was to clarify the prevalence, risk factors, and histological characteristics of precirrhotic PBC patients with PH.

Methods

This retrospective study compared the clinical features, histological characteristics, and response to ursodeoxycholic acid (UDCA) between the PH and non-PH groups of precirrhotic PBC patients.

Results

Out of 165 precirrhotic PBC patients, 40 (24.2%) also had PH. According to histological stage 1, 2 and 3 disease, 5.3% (1/19), 17.3% (17/98), and 45.8% (22/48) of patients also had PH, respectively. Precirrhotic PBC with PH was significantly positively correlated with bile duct loss, degree of cytokeratin 7 positivity, and degree of fibrosis in the portal area, but significantly negatively correlated with lymphoid follicular aggregation. Compared to the non-PH group, patients in the PH group showed a higher prevalence of obliterative portal venopathy, incomplete septal fibrosis, portal tract abnormalities and non-zonal sinusoidal dilatation (p<0.05). In addition, patients with PH were more likely to present with symptoms of jaundice, ascites, epigastric discomfort, a poorer response to UDCA, and more decompensation events (p<0.05). High alkaline phosphatase levels, low white blood cell counts, high Mayo scores, and high FIB-4 index values were risk factors for precirrhotic PBC with PH.

Conclusions

Approximately 24.2% of precirrhotic PBC patients have PH, which is histologically related to the injury of bile ducts. High alkaline phosphatase levels, low white blood cell counts, high Mayo scores, and high FIB-4 index values are associated with increased risk of precirrhotic PBC with PH.

Therapeutic approaches for cholestatic liver diseases: the role of nitric oxide pathway

Cholestasis describes bile secretion or flow impairment, which is clinically manifested with fatigue, pruritus, and jaundice. Neutrophils play a crucial role in many diseases such as cholestasis liver diseases through mediating several oxidative and inflammatory pathways. Data have been collected from clinical, in vitro, and in vivo studies published between 2000 and December 2021 in English and obtained from the PubMed, Google Scholar, Scopus, and Cochrane libraries. Although nitric oxide plays an important role in the pathogenesis of cholestatic liver diseases, excessive levels of NO in serum and affected tissues, mainly synthesized by the inducible nitric oxide synthase (iNOS) enzyme, can exacerbate inflammation. NO induces the inflammatory and oxidative processes, which finally leads to cell damage. We found that natural products such as baicalin, curcumin, resveratrol, and lycopene, as well as chemical likes ursodeoxycholic acid, dexamethasone, rosuvastatin, melatonin, and sildenafil, are able to markedly attenuate the NO production and iNOS expression, mainly through inducing the nuclear factor κB (NF-κB), Janus kinase and signal transducer and activator of transcription (JAK/STAT), and toll like receptor-4 (TLR4) signaling pathways. This study summarizes the latest scientific data about the bile acid signaling pathway, the neutrophil chemotaxis recruitment process during cholestasis, and the role of NO in cholestasis liver diseases. Literature review directed us to propose that suppression of NO and its related pathways could be a therapeutic option for preventing or treating cholestatic liver diseases.

New insights into the pathogenesis of primary biliary cholangitis asymptomatic stage

Primary biliary cholangitis (PBC) is a chronic cholestatic progressive liver disease and one of the most important progressive cholangiopathies in adults. Damage to cholangiocytes triggers the development of intrahepatic cholestasis, which progresses to cirrhosis in the terminal stage of the disease. Accumulating data indicate that damage to biliary epithelial cells [(BECs), cholangiocytes] is most likely associated with the intracellular accumulation of bile acids, which have potent detergent properties and damaging effects on cell membranes. The mechanisms underlying uncontrolled bile acid intake into BECs in PBC are associated with pH change in the bile duct lumen, which is controlled by the bicarbonate (HCO3-) buffer system "biliary HCO3- umbrella". The impaired production and entry of HCO3- from BECs into the bile duct lumen is due to epigenetic changes in expression of the X-linked microRNA 506. Based on the growing body of knowledge on the molecular mechanisms of cholangiocyte damage in patients with PBC, we propose a hypothesis explaining the pathogenesis of the first morphologic (ductulopenia), immunologic (antimitochondrial autoantibodies) and clinical (weakness, malaise, rapid fatigue) signs of the disease in the asymptomatic stage. This review focuses on the consideration of these mechanisms.

Prognostic scores in primary biliary cholangitis patients with advanced disease

BACKGROUND

Due to the chronic progressive disease characteristics of primary biliary cholangitis (PBC), patients with advanced PBC should not be ignored. Most prognostic score studies have focused on early stage PBC.

AIM

To compare the prognostic value of various risk scores in advanced PBC to help PBC patients obtain more monitoring and assessment.

METHODS

This study considered patients diagnosed with PBC during hospitalization between 2015 and 2021. The clinical stage was primarily middle and late, and patients usually took ursodeoxycholic acid (UDCA) after diagnosis. The discriminatory performance of the scores was assessed with concordance statistics at baseline and after 1 year of UDCA treatment. Telephone follow-up was conducted to analyze the course and disease-associated outcomes. The follow-up deadline was December 31, 2021. We compared the risk score indexes between those patients who reached a composite end point of death or liver transplantation (LT) and those who remained alive at the deadline. The combined performance of prognostic scores in estimating the risk of death or LT after 1 year of UDCA treatment was assessed using Cox regression analyses. Predictive accuracy was evaluated by comparing predicted and actual survival through Kaplan-Meier analyses.

RESULTS

We included 397 patients who were first diagnosed with PBC during hospitalization and received UDCA treatment; most disease stages were advanced. After an average of 6.4 ± 1.4 years of follow-up, 82 patients had died, and 4 patients had undergone LT. After receiving UDCA treatment for 1 year, the score with the best discrimination performance was the Mayo, with a concordance statistic of 0.740 (95% confidence interval: 0.690-0.791). The albumin-bilirubin, GLOBE, and Mayo scores tended to overestimate transplant-free survival. Comparing 7 years of calibration results showed that the Mayo score was the best model.

CONCLUSION

The Mayo, GLOBE, UK-PBC, and ALBI scores demonstrated comparable discriminating performance for advanced stage PBC. The Mayo score showed optimal discriminatory performance and excellent predictive accuracy.

Uncovering key molecules and immune landscape in cholestatic liver injury: implications for pathogenesis and drug therapy

Background: Cholestasis is a common pathological process in a variety of liver diseases that may lead to liver fibrosis, cirrhosis, and even liver failure. Cholestasis relief has been regarded as a principal target in the management of multiple chronic cholestasis liver diseases like primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC) at present. However, complicated pathogenesis and limited acknowledgments fettered therapeutic development. Therefore, this study aimed to systematically analyze miRNA-mRNA regulatory networks in cholestatic liver injury in order to provide new treatment strategies. Methods: Gene Expression Omnibus (GEO) database (GSE159676) was used to screen differentially expressed hepatic miRNAs and mRNAs in the PSC vs. control comparison and the PBC vs. control comparison, respectively. MiRWalk 2.0 tool was used to predict miRNA-mRNA pairs. Subsequently, functional analysis and immune cell infiltration analysis were performed to explore the pivotal functions of the target genes. RT-PCR was used to verify the result. Results: In total, a miRNA-mRNA network including 6 miRNAs (miR-122, miR-30e, let-7c, miR-107, miR-503, and miR-192) and 8 hub genes (PTPRC, TYROBP, LCP2, RAC2, SYK, TLR2, CD53, and LAPTM5) was constructed in cholestasis. Functional analysis revealed that these genes were mainly involved in the regulation of the immune system. Further analysis revealed that resting memory CD4 T cells and monocytes could potentially participate in cholestatic liver injury. The expressions of DEMis and eight hub genes were verified in ANIT-induced and BDL-induced cholestatic mouse models. Furthermore, SYK was found to have an impact on the response to UDCA, and its mechanism was possibly associated with complement activation and monocyte reduction. Conclusion: In the present study, a miRNA-mRNA regulatory network was constructed in cholestatic liver injury, which mostly mediated immune-related pathways. Moreover, the targeted gene SYK and monocytes were found to be related to UDCA response in PBC.

Endothelin receptor B enhances liver injury and pro-inflammatory responses by increasing G-protein-coupled receptor kinase-2 expression in primary biliary cholangitis

Severe diseases like cirrhosis and liver failure can be developed from primary biliary cholangitis (PBC). Endothelin-2 (EDN2) and endothelin receptor B (EDNRB) are related to the pathogenesis of PBC. However, the roles of EDN2 and EDNRB in PBC-related liver injury and inflammation along with molecular mechanisms are poorly defined. In this study, histopathologic alterations of liver tissues were assessed through hematoxylin-eosin staining. Alanine transaminase (ALT), alkaline phosphatase (ALP), aspartate transaminase (AST), and γ-Glutamyltranspetidase (GGT) (4 liver function indexes) serum levels were detected with corresponding activity assay kits. Also, we determined the levels of M2 subtype anti-mitochondrial antibody (AMA-M2), interferon-gamma (IFN-γ), and tumor-necrosis factor alpha (TNFα) in serum with ELISA assay. Later, RT-qPCR assay was used to measure the expression of genes at mRNA levels, while western blotting and immunohistochemical techniques were used to detect protein levels of genes. Our results showed that the liver tissues of PBC patients and mice presented with severe hepatocyte injury and inflammatory cell infiltration as well as destruction of intrahepatic small bile ducts. ALP, AST, ALT, GGT, AMA-M2, IFN-γ, and TNF-α serum levels were higher in PBC patients and mice. Besides, EDN2 and EDNRB were highly expressed in serums and livers of PBC patients and mice. EDNRB potentiated PBC-related liver injury and pro-inflammatory responses, as evidenced by observation of serious liver pathologic injury and increased serum levels of ALP, AST, ALT, AMA-M2, IFN-γ, and TNF-α in PBC mice following EDNRB overexpression. EDNRB overexpression or activation via its agonist IRL-1620 TFA triggered liver injury and pro-inflammatory responses, increased GRK2 expression and induced NF-κB expression and activation in wild-type mice. EDNRB knockdown or inhibition by Bosentan alleviated liver damage and inflammation, reduced GRK2 expression, and inhibited NF-κB in PBC mice. These findings suggested EDNRB loss or inhibition weakened liver injury and pro-inflammatory responses by down-regulating GRK2 and inhibiting the NF-κB pathway in PBC mice.

NADPH oxidase family proteins: signaling dynamics to disease management

Reactive oxygen species (ROS) are pervasive signaling molecules in biological systems. In humans, a lack of ROS causes chronic and extreme bacterial infections, while uncontrolled release of these factors causes pathologies due to excessive inflammation. Professional phagocytes such as neutrophils (PMNs), eosinophils, monocytes, and macrophages use superoxide-generating NADPH oxidase (NOX) as part of their arsenal of antimicrobial mechanisms to produce high levels of ROS. NOX is a multisubunit enzyme complex composed of five essential subunits, two of which are localized in the membrane, while three are localized in the cytosol. In resting phagocytes, the oxidase complex is unassembled and inactive; however, it becomes activated after cytosolic components translocate to the membrane and are assembled into a functional oxidase. The NOX isoforms play a variety of roles in cellular differentiation, development, proliferation, apoptosis, cytoskeletal control, migration, and contraction. Recent studies have identified NOX as a major contributor to disease pathologies, resulting in a shift in focus on inhibiting the formation of potentially harmful free radicals. Therefore, a better understanding of the molecular mechanisms and the transduction pathways involved in NOX-mediated signaling is essential for the development of new therapeutic agents that minimize the hyperproduction of ROS. The current review provides a thorough overview of the various NOX enzymes and their roles in disease pathophysiology, highlights pharmacological strategies, and discusses the importance of computational modeling for future NOX-related studies.

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.

Real-World Management of Patients with Primary Biliary Cholangitis-A Retrospective Study from a Tertiary Medical Center in Israel

Background: Primary biliary cholangitis (PBC) is a rare autoimmune liver disease with variation in prevalence, phenotype and prognosis across different geographical regions. Little is known about PBC in Israel. Our aim was to characterize the demography, clinical presentation, treatment patterns and prognosis in a cohort of PBC patients followed in a referral center in central Israel. Methods: Clinical, demographic and laboratory data were collected from the medical records of PBC patients followed at Tel Aviv Medical Center in the years 2003–2020. Results: We have identified 189 patients with a confirmed diagnosis of PBC; 92.6% were female and the mean age at diagnosis was 54.7 years. Thirty-nine percent were diagnosed with another autoimmune disease and 5.9% were diagnosed with a PBC-AIH (autoimmune hepatitis) variant syndrome. Ninety-six percent were treated with ursodeoxycholic acid (UDCA) at a mean dose of 13.3 mg/kg. A total of 28.1% were found with inadequate response to UDCA according to the Toronto criteria, and 53% of the UDCA non-responders were treated with bezafibrate. Younger age at diagnosis, higher baseline levels of alkaline phosphatase (ALP) and gamma-glutamyltransferase (GGT), AIH-PBC variant and positive anti-smooth muscle antibodies (ASMA) were associated with an inadequate UDCA response. In a multivariable analysis, higher ALP at diagnosis (OR = 1.92 CI 1.11–3.20 per 50-unit change, p = 0.018) and ASMA (OR = 27.6 CI 2.58–295, p = 0.006) independently predicted inadequate UDCA response. Higher alanine transaminase (ALT), ALP and GGT, lower albumin, younger age at diagnosis and pruritus conferred an increased risk for disease progression. Conclusions: Disease characteristics, treatment patterns, response to therapy and prognosis of a PBC patient cohort in a tertiary center in central Israel were revealed. The results highlight the importance of risk stratification in PBC, specifically in younger patients, those presenting with a high level of liver enzymes and in ASMA-positive patients with an assumed diagnosis of the AIH-PBC variant.

Changes of Serum IgG Glycosylation Patterns in Primary Biliary Cholangitis Patients

Objective

Primary biliary cholangitis (PBC) is an autoimmune cholestatic liver disease whose diagnosis is based significantly on autoantibody detection. This study aims to investigate the glycosylation profile of serum IgG in PBC patients using high-throughput lectin microarrays technology.

Method

Lectin microarray containing 56 lectins was used to detect and analyze the expression of serum IgG glycosylation in 99 PBC patients, 70 disease controls (DCs), and 38 healthy controls (HCs). Significant differences in PBC from control groups as well as across PBC subgroups positive for various autoantibodies were explored and verified by lectin blot technique.

Results

Lectin microarray detection revealed that compared to DC and HC groups, the specific glycan level of serum IgG sialic acid in PBC patients was increased. For each PBC subgroup, glycan levels of IgG mannose and galactose were decreased in AMA-M2 positive PBC patients compared to the AMA-M2 negative group. IgG N-Acetylgalactosamine (GalNAc) and fucose were decreased in anti-sp100 positive patients. IgG galactose was increased in anti-gp210 positive patients. IgG mannose was decreased in ACA-positive patients. Although the difference in overall sialic acid level was not observed using lectin blot, all results among the above PBC subgroups were consistent with the results of the technique.

Conclusion

Lectin microarray is an effective and reliable technique for analyzing glycan structure. PBC patients positive for different autoantibody exhibits distinct glycan profile. Altered levels of glycosylation may be related to the occurrence and development of the disease, which could provide a direction for new biomarker identification.

Management of Autoimmune Liver Diseases after Liver Transplantation

Autoimmune liver diseases are characterized by immune-mediated inflammation and eventual destruction of the hepatocytes and the biliary epithelial cells. They can progress to irreversible liver damage requiring liver transplantation. The post-liver transplant goals of treatment include improving the recipient’s survival, preventing liver graft-failure, and decreasing the recurrence of the disease. The keystone in post-liver transplant management for autoimmune liver diseases relies on identifying which would be the most appropriate immunosuppressive maintenance therapy. The combination of a steroid and a calcineurin inhibitor is the current immunosuppressive regimen of choice for autoimmune hepatitis. A gradual withdrawal of glucocorticoids is also recommended. On the other hand, ursodeoxycholic acid should be initiated soon after liver transplant to prevent recurrence and improve graft and patient survival in primary biliary cholangitis recipients. Unlike the previously mentioned autoimmune diseases, there are not immunosuppressive or disease-modifying agents available for patients with primary sclerosing cholangitis. However, colectomy and annual colonoscopy are key components during the post-liver transplant period.

The Management of Cholestatic Liver Diseases: Current Therapies and Emerging New Possibilities

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are two chronic cholestatic liver diseases affecting bile ducts that may progress to biliary cirrhosis. In the past few years, the increasing knowledge in the pathogenesis of both diseases led to a growing number of clinical trials and possible new targets for therapy. In this review, we provide an update on the treatments in clinical use and summarize the new drugs in trials for PBC and PSC patients. Farnesoid X Receptor (FXR) agonists and Pan-Peroxisome Proliferator-Activated Receptor (PPAR) agonists are the most promising agents and have shown promising results in both PBC and PSC. Fibroblast Growth Factor 19 (FGF19) analogues also showed good results, especially in PBC, while, although PBC and PSC are autoimmune diseases, immunosuppressive drugs had disappointing effects. Since the gut microbiome could have a potential role in the pathogenesis of PSC, recent research focused on molecules that could change the microbiome, with good results. The near future of the medical management of these diseases may include new treatments or a combination of multiple drugs targeting different signaling pathways at different stages of the diseases.

Antimitochondrial Antibodies and Primary Biliary Cholangitis in Patients with Polymyalgia Rheumatica/Giant Cell Arteritis

Background and Objectives: Laboratory liver abnormalities can be observed in patients affected with polymyalgia rheumatica (PMR) and/or giant cell arteritis (GCA), especially with a cholestatic pattern. The first objective of our review article is to discuss the potential link between antimitochondrial antibodies (AMA) and/or primary biliary cholangitis (PBC) and PMR/GCA, according to the evidences of literature. The second objective is to discuss the association of PMR/GCA with the other rheumatic diseases having PBC as a common manifestation. Materials and Methods: A literature search was performed on PubMed and Medline (OVID interface) using these terms: polymyalgia rheumatica, giant cell arteritis, antimitochondrial antibodies, primary biliary cholangitis, primary Sjogren’s syndrome, systemic sclerosis, and systemic lupus erythematosus. The search was restricted to all studies and case reports published in any language. Reviews, conference abstracts, comments, and non-original articles were excluded; however, each review’s reference list was scanned for additional publications meeting this study’s aim. When papers reported data partially presented in previous articles, we referred to the most recent published data. Results and Conclusions: Our literature search highlighted that cases reporting an association between AMA, PBC and PMR/GCA were very uncommon; AMA antigenic specificity had never been detected and biopsy-proven PBC was reported only in one patient with PMR/GCA. Finally, the association of PMR/GCA with autoimmune rheumatic diseases in which PBC is relatively common was anecdotal.

Analysis of Autoantibodies against Promyelocytic Leukemia Nuclear Body Components and Biochemical Parameters in Sera of Patients with Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease characterized by immune-mediated destruction of intrahepatic bile ducts and the presence of specific antibodies. The aim of the study was to examine the diagnostic significance of antibodies against promyelocytic leukemia nuclear body (PML NB) components such as Sp100, Sp140, and PML in a cohort of PBC patients and compare the results with biochemical and histological parameters. Serum samples were collected from 93 PBC patients. Anti-Sp100 and anti-PML antibodies were assessed using commercially available kits, anti-Sp140 using developed “in-house” ELISA test. Anti-Sp140, anti-Sp100, and anti-PML antibodies were present in 25 (27%), 37 (40%), and 29 (31%) PBC patients, respectively. Anti-PML NB positive patients also showed increased concentration of bilirubin and alkaline phosphatase (p < 0.05). In the group with the presence of at least two types of these antibodies, more frequent deaths or transplantations were observed. A correlation between the presence of antibodies and histological grade (OR = 2.55 p = 0.039) was established. Patients with bilirubin > 1.1 mg/dL at the time of diagnosis had a significantly shorter time of survival than patients with bilirubin ≤ 1.1 mg/dL (HR 5.7; 95% C.I., 2.7, 12.3; p < 0.001). Our data confirm very high specificity of anti-PML NB antibodies, which can expand the laboratory diagnostic capabilities of PBC. We found an association between positive reactivity of autoantibodies directed against components of PML nuclear bodies and higher concentrations of bilirubin and alkaline phosphatase, but the main prognostic marker of survival remains serum bilirubin.

Widespread gaps in the quality of care for primary biliary cholangitis in UK

OBJECTIVE

Primary biliary cholangitis (PBC) is a progressive, autoimmune, cholestatic liver disease affecting approximately 15 000 individuals in the UK. Updated guidelines for the management of PBC were published by The European Association for the Study of the Liver (EASL) in 2017. We report on the first national, pilot audit that assesses the quality of care and adherence to guidelines.

DESIGN

Data were collected from 11 National Health Service hospitals in England, Wales and Scotland between 2017 and 2020. Data on patient demographics, ursodeoxycholic acid (UDCA) dosing and key guideline recommendations were captured from medical records. Results from each hospital were evaluated for target achievement and underwent χ² analysis for variation in performance between trusts.

RESULTS

790 patients' medical records were reviewed. The data demonstrated that the majority of hospitals did not meet all of the recommended EASL standards. Standards with the lowest likelihood of being met were identified as optimal UDCA dosing, assessment of bone density and assessment of clinical symptoms (pruritus and fatigue). Significant variations in meeting these three standards were observed across UK, in addition to assessment of biochemical response to UDCA (all p<0.0001) and assessment of transplant eligibility in high-risk patients (p=0.0297).

CONCLUSION

Our findings identify a broad-based deficiency in 'real-world' PBC care, suggesting the need for an intervention to improve guideline adherence, ultimately improving patient outcomes. We developed the PBC Review tool and recommend its incorporation into clinical practice. As the first audit of its kind, it will be used to inform a future wide-scale reaudit.

Familial associations between autoimmune hepatitis and primary biliary cholangitis and other autoimmune diseases

Autoimmune hepatitis (AH) and primary biliary cirrhosis (PBC) are autoimmune diseases (AIDs) targeting cellular components of the liver. Being rare diseases, limited data are available about familial risks among these AIDs (concordant) or between them and other AIDs (discordant). We aimed to carry out an unbiased study on these AIDs based on medically diagnosed patients. We collected data on patients diagnosed in Swedish hospitals with AH, PBC and other AIDs and calculated familial standardized incidence ratios (SIRs) for concordant and discordant familial relative risks. The number of AH patients was 6,269, of whom 43.0% were male; patient numbers for PBC were 4,269, with 17.8% males. AH accounted for 0.8% and 0.6% of all hospitalized AIDs in Sweden. For AH only the familial risk between siblings was significant (3.83). For PBC the risks for offspring of parents (9.05) and siblings (10.88) were high, but only risk for females was significant. Spousal risks were very high, 5.91 and 6.07 for AH. Risk for AH was 2.21 in families of PBC, and it was 2.47 for PBC in families of AH patients. Among other AIDs, 14 showed a significant association with AH, compared to 16 AIDs with PBC. The surprising finding in this nation-wide family study on medically diagnosed patients was the high risk for AH (6.0) between spouses, which exceed the risk between siblings, suggesting the existence of strong environmental risk factors. AH and PBC were associated with multiple other AIDs. The results call attention to environmental factors in AID etiology which should also be in focus in taking anamnestic data from patients.

Kupffer Cells Regulate Natural Killer Cells Via the NK group 2, Member D (NKG2D)/Retinoic Acid Early Inducible-1 (RAE-1) Interaction and Cytokines in a Primary Biliary Cholangitis Mouse Model

Background

Kupffer cells and natural killer (NK) cells has been identified as contributing factors in the pathogenesis of hepatitis, but the detailed mechanism of these cell types in the pathogenesis of primary biliary cholangitis (PBC) is poorly understood.

Material/Methods

In this study, polyinosinic: polycytidylic acid (poly I: C), 2-octynoic acid-bovine serum albumin (2OA-BSA) and Freund’s adjuvant (FA) were injected to establish a murine PBC model, from which NK cells and Kupffer cells were extracted and isolated. The cells were then co-cultivated in a designed culture system, and then NK group 2, member D (NKG2D), retinoic acid early inducible-1 (RAE-1), F4/80, and cytokine expression levels were detected.

Results

The results showed close crosstalk between Kupffer cells and NK cells. PBC mice showed increased surface RAE-1 protein expression and Kupffer cell cytokine secretion, which subsequently activated NK cell-mediated target cell killing via NKG2D/RAE-1 recognition, and increased inflammation. NK cell-derived interferon-γ (IFN-γ) and Kupffer cell-derived tumor necrosis factor α (TNF-α) were found to synergistically regulate inflammation. Moreover, interleukin (IL)-12 and IL-10 improved the crosstalk between NK cells and Kupffer cells.

Conclusions

Our findings in mice are the first to suggest the involvement of the NKG2D/RAE-1 interaction and cytokines in the synergistic effects of NK and Kupffer cells in PBC.