The immunopathology of liver granulomas in primary biliary cirrhosis

Granulomatous liver diseases

A granuloma is a discrete collection of activated macrophages and other inflammatory cells. Hepatic granulomas can be a manifestation of localized liver disease or be a part of a systemic process, usually infectious or autoimmune. A liver biopsy is required for the detection and evaluation of granulomatous liver diseases. The prevalence of granulomas on liver biopsy varies from 1% to 15%. They may be an incidental finding in an asymptomatic individual, or they may represent granulomatous hepatitis with potential to progress to liver failure, or in chronic disease, to cirrhosis. This review focuses on pathogenesis, histological features of granulomatous liver diseases, and most common etiologies, knowledge that is essential for timely diagnosis and intervention.

Interstitial Lung Disease in Primary Biliary Cholangitis: A Cohort Prospective Study

Interstitial lung disease (ILD) has been recognized as an extrahepatic manifestation ofprimary biliary cholangitis (PBC), althoughlimited data are available on its prevalence and clinical significance. Therefore, we evaluated the occurrence and clinical features of ILD in a cohort of PBC patients. Ninety-three individuals without concomitant rheumatic diseases were enrolled in our prospective cohort study. All patients underwent chest high-resolution computed tomography (HRCT). Liver-related and lung-related survival wereassessed. A lung-related outcome was defined as death from ILD complications; a liver-related outcome was defined as liver transplantation or death from liver cirrhosis complications. HRCT findings suggestive ofILD were detected in 38 patients (40.9%). A sarcoid-like pattern of PBC-associated ILD was the most frequent, followed by subclinical ILD and organizing pneumonia. Patients with ILD were less likely to have liver cirrhosis and liver-related symptoms and presented with higher serum immunoglobulin M(IgM) and M2 subtype antimitochondrial antibodies (AMA-M2) positivity rates. In a multivariate analysis, the absence of liver disease symptoms at the disease presentation (OR 11.509; 95% CI 1.210-109.421; p = 0.033), the presence of hepatic non-necrotizing epithelioid cell granulomas (OR 17.754; 95% CI 1.805-174.631; p = 0.014), higher serum IgM (OR 1.535; 95% CI 1.067-2.208; p = 0.020) and higher blood leukocyte count (OR 2.356; 95% CI 1.170-4.747; p = 0.016) were independent risk factors associated with ILD in PBC. More than a third of patients with ILD showed no respiratory symptoms, and only one ILD-related death occurred during a follow-up of 29.0 months (IQR 11.5; 38.0). Patients with ILD had better liver transplant-free survival.ILD in PBC had a benign course and was associated with a lower liver disease severity. PBC-associated ILD should be included in a list of differential diagnoses of ILD.

The immunological characteristics of TSPAN1 expressing B cells in autoimmune hepatitis

Background and aims

Tetraspanin proteins are closely related to the functional changes of B cells, including antigen presentation, production of cytokines, and transduction. We aim to explore the potential role of Tetraspanin 1 (TSPAN1) in the biological activities of B cells in AIH.

Methods and results

Herein, this study found that numbers of cells expressing TSPAN1 were significantly increased in AIH patients compared to PBC, chronic hepatitis B, and healthy control (P < 0.0001). Moreover, there was a positive correlation between numbers of TSPAN1+ cells and AIH disease severity (P < 0.0001). Immunofluorescence staining further confirmed that TSPAN1 was primarily expressed on CD19+ B cells. Flow-cytometric analysis showed that TSPAN1+ B cells secreted more inflammatory cytokines and expressed higher level of CD86 than TSPAN1- B cells. Furthermore, compared with TSAPN1- cells, the expression of CXCR3 on TSPAN1+ cells was also higher. Meanwhile, CXCL10, the ligand of CXCR3, was significantly elevated in the liver of AIH (P < 0.01) and had positive correlation with the quantities of TSPAN1 (P < 0.05). Interestingly, the numbers of TSPAN1+ B cells were decreased in AIH patients after immunosuppressive therapy.

Conclusions

TSPAN1⁺ B cells in the liver may promote the progression of AIH via secreting cytokines and presenting antigens. The chemotactic movement of TSPAN1⁺ B cells toward the liver of AIH was possibly due to CXCR3 - CXCL10 interaction.

MutT Homolog 1 Inhibitor Karonudib Attenuates Autoimmune Hepatitis by Inhibiting DNA Repair in Activated T Cells

Autoimmune hepatitis (AIH) is an inflammatory liver disease driven by the hyperactivation of various intrahepatic antigen-specific T cells due to a breach of immune tolerance. Studies in immunometabolism demonstrate that activated T cells harbor increased levels of reactive oxygen species that cause oxidative DNA damage. In this study, we assessed the potential of DNA damage repair enzyme MutT homolog 1 (MTH1) as a therapeutic target in AIH and karonudib as a novel drug for patients with AIH. We report herein that MTH1 expression was significantly increased in liver samples from patients with AIH compared to patients with chronic hepatitis B and nonalcoholic fatty liver disease and from healthy controls. In addition, the expression of MTH1 was positively correlated with AIH disease severity. We further found abundant T cells that expressed MTH1 in AIH. Next, we found that karonudib significantly altered T-cell receptor signaling in human T cells and robustly inhibited proliferation of human T cells in vitro. Interestingly, our data reflected a preferential inhibition of DNA damage repair in activated T cells by karonudib. Moreover, MTH1 was required to develop liver inflammation and damage because specific deletion of MTH1 in T cells ameliorated liver injury in the concanavalin A (Con A)-induced hepatitis model by inhibiting T-cell activation and proliferation. Lastly, we validated the protective effect of karonudib on the Con A-induced hepatitis model. Conclusion: MTH1 functions as a critical regulator in the development of AIH, and its inhibition in activated T cells reduces liver inflammation and damage.

Cyr61 Alleviates Cholangitis by Inhibiting Cytotoxic Effects of CD8+ T Cells on Biliary Epithelial Cells

OBJECTIVE

Primary biliary cholangitis (PBC) is a chronic progressive cholestatic liver disease. In recent years, researchers have found that cysteine-rich angiogenic inducer 61 (Cyr61, also known as CCN1) has a potential role in reducing portal inflammation in patients with PBC. This study aimed to explore the relationship between Cyr61 and PBC to provide new ideas and an experimental basis for the clinical treatment of PBC.

METHODS

After induction of the overexpression of Cyr61 in a mouse model of PBC using recombinant adenovirus, hematoxylin and eosin staining and pathological scores were used to indicate intrahepatic inflammation and bile duct damage. Real-time PCR was used to detect changes in inflammation-related cytokines in the liver. To further study the mechanism, we assessed whether Cyr61 protects bile duct epithelial cells from cytotoxic effects.

RESULTS

Serum and hepatic Cyr61 levels were increased in the murine model of PBC. Overexpression of Cyr61 alleviated hepatic inflammation and bile duct injury in vivo. Cyr61 inhibited the cytotoxic effects of CD8⁺ T cells by acting on biliary epithelial cells (BECs) in vitro.

CONCLUSION

Our results provide novel insight into the pathogenesis of PBC and suggest that Cyr61 plays a dominant role in the cytotoxic effects on BECs in PBC. Consequently, therapeutic strategies targeting Cyr61 could be a potent therapy for PBC.

The Clinical Significance of Hepatic CD69+ CD103+ CD8+ Resident-Memory T Cells in Autoimmune Hepatitis

BACKGROUND AND AIMS

The diverse inflammatory response found in the liver of patients with autoimmune hepatitis (AIH) is well established, but identification of potentially pathogenic subpopulations has proven enigmatic.

APPROACH AND RESULTS

We report herein that CD69⁺ CD103⁺ CD8⁺ tissue-resident memory T cells (T_RM ) are significantly increased in the liver of patients with AIH compared to chronic hepatitis B, NAFLD, and healthy control tissues. In addition, there was a significant statistical correlation between elevation of CD8⁺ T_RM cells and AIH disease severity. Indeed, in patients with successful responses to immunosuppression, the frequencies of such hepatic CD8⁺ T_RM cells decreased significantly. CD69⁺ CD8⁺ and CD69⁺ CD103⁺ CD8⁺ T cells, also known as CD8⁺ T_RM cells, reflect tissue residency and are well known to provide intense immune antigenic responses. Hence, it was particularly interesting that patients with AIH also manifest an elevated expression of IL-15 and TGF-β on inflammatory cells, and extensive hepatic expression of E-cadherin; these factors likely contribute to the development and localization of CD8⁺ T_RM cells. Based on these data and, in particular, the relationships between disease severity and CD8⁺ T_RM cells, we studied the mechanisms involved with glucocorticoid (GC) modulation of CD8⁺ T_RM cell expansion. Our data reflect that GCs in vitro inhibit the expansion of CD8⁺ T_RM cells induced by IL-15 and TGF-β and with direct down-regulation of the nuclear factor Blimp1 of CD8⁺ T_RM cells.

CONCLUSIONS

Our data suggest that CD8⁺ T_RM cells play a critical role in the pathogenesis of AIH, and GCs attenuate hepatic inflammation through direct inhibition of CD8⁺ T_RM cell expansion.

Tectorigenin alleviates intrahepatic cholestasis by inhibiting hepatic inflammation and bile accumulation via activation of PPARγ

BACKGROUND AND PURPOSE

Increasing evidence suggests that human cholestasis is closely associated with the accumulation and activation of hepatic macrophages. Research indicates that activation of PPARγ exerts liver protective effects in cholestatic liver disease (CLD), particularly by ameliorating inflammation and fibrosis, thus limiting disease progression. However, existing PPARγ agonists, such as troglitazone and rosiglitazone, have significant side effects that prevent their clinical application in the treatment of CLD. In this study, we found that tectorigenin alleviates intrahepatic cholestasis in mice by activating PPARγ.

EXPERIMENTAL APPROACH

Wild-type mice were intragastrically administered α-naphthylisothiocyanate (ANIT) or fed a diet containing 0.1% 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) to simultaneously establish an experimental model of intrahepatic cholestasis and tectorigenin intervention, followed by determination of intrahepatic cholestasis and the mechanisms involved. In addition, PPARγ-deficient mice were administered ANIT and/or tectorigenin to determine whether tectorigenin exerts its liver protective effect by activating PPARγ.

KEY RESULTS

Treatment with tectorigenin alleviated intrahepatic cholestasis by inhibiting the recruitment and activation of hepatic macrophages and by promoting the expression of bile transporters via activation of PPARγ. Furthermore, tectorigenin increased expression of the bile salt export pump (BSEP) through enhanced PPARγ binding to the BSEP promoter. In PPARγ-deficient mice, the hepatoprotective effect of tectorigenin during cholestasis was blocked.

CONCLUSION AND IMPLICATIONS

In conclusion, tectorigenin reduced the recruitment and activation of hepatic macrophages and enhanced the export of bile acids by activating PPARγ. Taken together, our results suggest that tectorigenin is a candidate compound for cholestasis treatment.

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.

Primary Sclerosing Cholangitis and Primary Biliary Cirrhosis Overlap Syndrome: A Review

Primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC) are slow progressive diseases which have been increasing in prevalence. The pathogeneses of PBC and PSC are incompletely understood but the underlying mechanisms appear to be fundamentally autoimmune in origin. Although PBC and PSC appear to be separate entities, overlap has been described. Diagnosis depends on a combination of serological markers, imaging, and pathological criteria. The mainstay of treatment has been ursodeoxycholic acid and in some cases of extrahepatic biliary obstruction and overlap disorder, endoscopic retrograde cholangiopancreatography has been useful.

Immune system and cholangiocytes: A puzzling affair in primary biliary cholangitis

Primary biliary cholangitis (PBC) is a cholestatic liver disease characterized by the destruction of the small and medium bile ducts. Its pathogenesis is still unknown. Despite the genome wide association study findings, the therapies targeting the cytokines pathway, tested so far, have failed. The concept of the biliary epithelium as a key player of the PBC pathogenesis has emerged over the last few years. It is now well accepted that the biliary epithelial cells (BECs) actively participate to the genesis of the damage. The chronic stimulation of BECs via microbes and bile changes the cell phenotype toward an active state, which, across the production of proinflammatory mediators, can recruit, retain, and activate immune cells. The consequent immune system activation can in turn damage BECs. Thus, the crosstalk between both innate and adaptive immune cells and the biliary epithelium creates a paracrine loop responsible for the disease progression. In this review, we summarize the evidence provided in literature about the role of BECs and the immune system in the pathogenesis of PBC. We also dissect the relationship between the immune system and the BECs, focusing on the unanswered questions and the future potential directions of the translational research and the cellular therapy in this area.

Immunological abnormalities in patients with primary biliary cholangitis

Primary biliary cholangitis (PBC), an autoimmune liver disease occurring predominantly in women, is characterized by high titers of serum anti-mitochondrial antibodies (AMAs) and progressive intrahepatic cholestasis. The immune system plays a critical role in PBC pathogenesis and a variety of immune cell subsets have been shown to infiltrate the portal tract areas of patients with PBC. Amongst the participating immune cells, CD4 T cells are important cytokine-producing cells that foster an inflammatory microenvironment. Specifically, these cells orchestrate activation of other immune cells, including autoreactive effector CD8 T cells that cause biliary epithelial cell (BEC) injury and B cells that produce large quantities of AMAs. Meanwhile, other immune cells, including dendritic cells (DCs), natural killer (NK) cells, NKT cells, monocytes, and macrophages are also important in PBC pathogenesis. Activation of these cells initiates and perpetuates bile duct damage in PBC patients, leading to intrahepatic cholestasis, hepatic damage, liver fibrosis, and eventually cirrhosis or even liver failure. Taken together, the body of accumulated clinical and experimental evidence has enhanced our understanding of the immunopathogenesis of PBC and suggests that immunotherapy may be a promising treatment option. Herein, we summarize current knowledge regarding immunological abnormalities of PBC patients, with emphasis on underlying pathogenic mechanisms. The differential immune response which occurs over decades of disease activity suggests that different therapies may be needed at different stages of disease.

The Immunobiology of Receptor Activator for Nuclear Factor Kappa B Ligand and Myeloid-Derived Suppressor Cell Activation in Immunoglobulin G4-Related Sclerosing Cholangitis

The primary function of myeloid-derived suppressor cells (MDSCs) is reflected in their immune modulatory role in several immune-mediated diseases. In immunoglobulin G4 (IgG4)-related disease (IgG4-RD), it has been hypothesized that there are selective regulatory defects that lead to a T helper 2 (Th2) bias immune response. Herein we have taken advantage of a large cohort of patients with IgG4-related sclerosing cholangitis (IgG4-SC), the most common extrapancreatic involvement of IgG4-RD, as well as controls consisting of primary sclerosing cholangitis, autoimmune hepatitis, and healthy volunteers, to study MDSCs. We report dramatically increased levels of receptor activator for nuclear factor kappa B ligand (RANKL) expression in serum and liver from patients with IgG4-SC compared to both liver-disease and healthy controls. Moreover, in IgG4-SC liver, RANKL-secreting cells specifically colocalized with cluster of differentiation 38-positive plasma cells and MDSCs, particularly monocytic MDSCs, and express the RANKL receptor in liver. Similarly, the frequency and number of peripheral blood MDSCs were significantly increased. Importantly, serum expression levels of RANKL were inversely correlated with the serum level of gamma-glutamyltransferase but significantly positively correlated with the frequency of MDSCs. Moreover, we confirmed that RANKL induced the expansion and activation of MDSCs through the RANKL/RANK/nuclear factor kappa B signal pathway. Of note, RANKL-treated MDSCs suppressed T-cell proliferation and induced Th2 differentiation. Conclusion: Our data suggest that plasma cell-derived RANKL induces the expansion and activation of MDSCs, which suppress T-cell proliferation and contribute to the Th2-type response characteristic of IgG4-SC.

Myeloid Cells and Chronic Liver Disease: a Comprehensive Review

Myeloid cells play a major role in the sensitization to liver injury, particularly in chronic inflammatory liver diseases with a biliary or hepatocellular origin, and the interplay between myeloid cells and the liver may explain the increased incidence of hepatic osteodystrophy. The myeloid cell-liver axis involves several mature myeloid cells as well as immature or progenitor cells with the complexity of the liver immune microenvironment aggravating the mist of cell differentiation. The unique positioning of the liver at the junction of the peripheral and portal circulation systems underlines the interaction of myeloid cells and hepatic cells and leads to immune tolerance breakdown. We herein discuss the scenarios of different chronic liver diseases closely modulated by myeloid cells and illustrate the numerous potential targets, the understanding of which will ultimately steer the development of solid immunotherapeutic regimens. Ultimately, we are convinced that an adequate modulation of the liver microenvironment to modify the functional and quantitative characteristics of myeloid cells will be a successful approach to treating chronic liver diseases of different etiologies.

Recent advances in the diagnosis and treatment of primary biliary cholangitis

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

Quantitation of the Rank-Rankl Axis in Primary Biliary Cholangitis

There is substantial data that suggests an abnormality of innate immunity in patients with primary biliary cholangitis (PBC) which includes the transcription factor nuclear factor-kB (NF-kB) and well as downstream inflammatory signaling pathways. In addition, ImmunoChip analysis has identified a novel PBC-associated locus near the receptor activator of NF-kB ligand (RANKL) gene. Based on these observations, we investigated the role of the RANKL axis in the liver of patients with PBC compared to controls. We used immunohistochemistry to quantitate liver expression of RANKL, its receptor (RANK), and importantly the decoy receptor osteoprotegerin (OPG), including a total of 122 liver samples (PBC = 37, primary sclerosing cholangitis = 20, autoimmune hepatitis = 26, chronic hepatitis B = 32 and unaffected controls = 7). In addition, we studied RANKL-RANK-OPG co-localization in CD4 and CD8 T cells, B cells, dendritic cells, macrophages, NK, NKT cells, hepatocytes, and cholangiocytes. We report herein that RANK is constitutively expressed by cholangiocytes in both unaffected and diseased liver. However, cholangiocytes from PBC express significantly higher levers of RANK than either the unaffected controls or liver diseased controls. CD4, CD8 and CD19 cells with in the portal areas around bile ducts in PBC express significantly higher levels of RANKL compared to controls. Importantly, the overall hepatic RANKL level and the ratio of hepatic RANKL/OPG correlated with disease severity in PBC. In conclusion, our data indicate a role of RANK-RANKL axis in the innate immune activation in PBC and we hypothesize that the damaged cholangiocytes, which express high levels of RANK, lead to the recruitment of RANKL positive cells and ultimately the classic portal tract infiltrates.

Liver damage in primary biliary cirrhosis and accompanied by primary Sjögren's syndrome: a retrospective pilot study

Introduction

Primary biliary cirrhosis (PBC) and primary Sjögren's syndrome (pSS) have been referred to as “generalized autoimmune epithelitis”. Indeed, the pathogenic mechanisms, clinical features, and optimal therapeutic approaches for them are not yet fully defined.

Material and methods

A retrospective analysis was carried out on clinical data obtained from 302 inpatients newly diagnosed with PBC, pSS, or the coexistence of PBC and SS between May 2011 and December 2014. Forty-two patients with abnormal hepatic function were divided into the PBC group (n = 17), the coexistent group (PBC accompanied by SS, n = 13), and the pSS group (n = 12). Their clinical symptoms, laboratory data, and pathological features were collected and analyzed when they were first diagnosed. The clinical and laboratory data were collected at 0, 1, and 3 months after treatment.

Results

Of the 42 patients with abnormal liver function, 4 were male and 38 were female patients. Compared with the patients in the PBC group, the patients in the other 2 groups were more likely to have an elevated erythrocyte sedimentation rate (ESR) and serum immunoglobulin G (IgG) levels. Abnormal serum immunoglobulin M levels (IgM) were more frequent in the PBC group. Corticosteroids were effective in normalizing elevated liver enzyme levels in patients with SS and in those with coexistent conditions.

Conclusions

This pilot study suggests that patients with PBC, pSS, and PBC/SS coexistence and having liver function abnormality share similar symptoms, but have different pathogenesis and prognosis.

It is time to change primary biliary cirrhosis (PBC): New nomenclature from "cirrhosis" to "cholangitis", and upcoming treatment based on unveiling pathology

Primary biliary cirrhosis (PBC) is a chronic, organ-specific, autoimmune liver disease characterized by progressive cholestasis, eventually leading to cirrhosis. Several lines of evidence have revealed a crucial role of adaptive as well as innate immune responses in the etiopathogenesis of PBC, and more recently, the biology of bile duct cells and genome-wide association studies (GWAS) demonstrated several key molecules and pathways in this enigmatic disease. Although ursodeoxycholic acid (UDCA) has been the only approved drug for PBC with clinical evidences for improvement of long-term outcomes, a substantial population have suboptimal responses to UDCA, resulting in unfavorable outcomes. In this regard, second-line treatment for patients refractory to UDCA is strongly awaited. In Japan, bezafibrate (BF) has been frequently used for this purpose, yet recent clinical trials failed to clearly demonstrate clinical efficacy of BF. Novel pharmacotherapies targeted to key molecules and pathways in PBC are upcoming. Finally, we sincerely call on all members of the Japan Society of Hepatology to use from this moment on the name "primary biliary cholangitis" for the disease known by its abbreviation PBC, in keeping with a very recent global agreement.

Extrahepatic autoimmune conditions associated with primary biliary cirrhosis

There is a paucity of information on extrahepatic autoimmune (EHA) conditions associated with primary biliary cirrhosis (PBC) and on the impact of EHA conditions on PBC patients' survival. Our goal was to assess the association between PBC and other autoimmune diseases and the impact of EHA conditions on the natural history of PBC. We took advantage of 361 consecutive PBC patients enrolled between 1975 and 2012 (22 males, 339 females; mean follow-up 8 ± 6.9 years). Any associated EHA conditions, PBC histological stage at diagnosis, biochemical data, physiological history, and extrahepatic malignancies developing during the follow-up were recorded. Survival was analyzed by means of Kaplan-Meier curves. Importantly, 221 patients (61.2 %) had at least one EHA conditions: 45 patients (20.4 %) had Hashimoto thyroiditis; 7 (3.2 %) had Graves' thyroiditis; 65 (29.4 %) had Raynaud's phenomenon; 124 (56.1 %) had Sjogren's syndrome; 8 (3.6 %) had systemic lupus erythematosus; 22 (9.9 %) had scleroderma; 22 (9.9 %) had rheumatoid arthritis; 18 (8.1 %) had cutaneous autoimmune diseases; 8 (3.6 %) had vasculitis; 5 (1.4 %) had celiac disease; and 25 (13.1 %) had other EHA conditions. The proportion of patients with associated EHA conditions enrolled during representative periods (1975-1980, 1981-1990, 1991-2000, 2001-2010, 2011-2012) remained stable. No differences emerged between patients with versus without EHA conditions in terms of mean age at PBC diagnosis, antimitochondrial antibody (AMA), or antinuclear antibody (ANA) positivity, histological stage at diagnosis, smoking habits, alcohol consumption, or BMI >25. Multiple logistic regression analysis showed that only female gender was significantly associated with positivity for EHA conditions (OR 4.8; 95 % CI 1.6-13.7, p = 0.004). The mean survival after the diagnosis of PBC was much the same in patients with and without EHA conditions. In conclusion, EHA conditions are often associated with PBC, especially in female patients, but they do not reduce patient survival.

Women and primary biliary cirrhosis

Primary biliary cirrhosis occurs more frequently in women, and previous studies indicated that the average age of primary biliary cirrhosis (PBC) onset makes pregnancy in PBC patients uncommon. However, more recently, improved diagnostic testing has enabled detection of PBC in younger women, including those of childbearing age. This has led investigators to become increasingly interested in the relationship between the ontogeny of PBC and pregnancy. Published cases indicate that the typical age for pregnant women to be diagnosed with PBC is in the early 30s, and that during gestation, pruritus and jaundice are the most common symptoms. During gestation, susceptible women may experience onset of PBC resulting from the drastic changes in female hormones; this would include not only the mitochondrial damage due to accumulation of bile acids but also changes in the immune response during the different stages of pregnancy that might play an important role in the breakdown of self-tolerance. The mechanisms underlying the potential relationship between PBC and pregnancy warrant further investigation. For women first diagnosed with PBC during gestation, or those for whom first appearance of a flare up occurs during and postpartum, investigation of the immune response throughout gestation could provide new avenues for immunologic therapeutic intervention and the discovery of new treatment strategies for PBC.

More on hepatic granulomas

We have read the case report of Nihon-Yanagi et al. The patient they described developed hepatic granuloma two times and the granulomatous lesion was surrounding metal staples/clips suggesting that the granuloma was due to surgical staples/clips.

Hepatic granulomas (HGs) are reported in around 5 % of patient who undergo a liver biopsy and caused by several diseases including sarcoidosis, tuberculosis, hydatid cyst, brucellosis, typhoid fever, chronic hepatitis B and C and primary biliary cirrhosis (PBC). Chronic hepatitis B and C infections are the most common and serious causes of liver damage in patient with renal failure. Their prevalence is a higher than people without renal failure. We have previously reported that the prevalences of HGs in patients with chronic hepatitis B and C are 1.5 and 1.3 % respectively. The described patient was on hemodialysis for 12 years. The other causes of HG seem excluded; however hepatitis B and C infections and PBC should have been tested and excluded before ascribing the HGs to surgical staples/clipping material.

Contrast-enhanced micro-computed tomography using ExiTron nano6000 for assessment of liver injury

AIM: To explore the potential of contrast-enhanced computed tomography (CECT) using ExiTron nano6000 for assessment of liver lesions in mouse models.

METHODS: Three mouse models of liver lesions were used: bile duct ligation (BDL), lipopolysaccharide (LPS)/D-galactosamine (D-GalN), and alcohol. After injection with the contrast agent ExiTron nano6000, the mice were scanned with micro-CT. Liver lesions were evaluated using CECT images, hematoxylin and eosin staining, and serum aminotransferase levels. Macrophage distribution in the injury models was shown by immunohistochemical staining of CD68. The in vitro studies measured the densities of RAW264.7 under different conditions by CECT.

RESULTS: In the in vitro studies, CECT provided specific and strong contrast enhancement of liver in mice. CECT could present heterogeneous images and densities of injured livers induced by BDL, LPS/D-GalN, and alcohol. The liver histology and immunochemistry of CD68 demonstrated that both dilated biliary tracts and necrosis in the injured livers could lead to the heterogeneous distribution of macrophages. The in vitro study showed that the RAW264.7 cell masses had higher densities after LPS activation.

CONCLUSION: Micro-CT with the contrast agent ExiTron nano6000 is feasible for detecting various liver lesions by emphasizing the heterogeneous textures and densities of CECT images.

Interstitial lung disease preceding primary biliary cirrhosis in a male patient

A 47-year-old male was admitted with subacute onset of dry cough and fever. Chest tomography demonstrated multifocal areas of consolidation and ground glass attenuation. Cytological analysis of bronchoalveolar lavage revealed lymphocytosis and eosinophilia and anatomopathological exam of transbronchial cryobiopsy showed poorly formed non-caseous granulomas associated to interstitial lympho-plasmocitary infiltrate. The diagnosis of idiopathic granulomatous lung disease (GLD) was assumed and the patient started oral prednisolone, presenting clinical, functional and radiological improvement. Two years later, the patient was diagnosed with primary biliary cirrhosis (PBC). At this time, it was possible to associate GLD with the autoimmune hepatobiliary disease. Clinical, epidemiological and pathological aspects of this uncommon case of interstitial lung disease as first presentation of PBC in a male patient are discussed.

A Potential Profibrogenic Role of Biliary Epithelium-Derived Cardiotrophin-1 in Pediatric Cholestatic Liver Disease

As a cytokine of the interleukin-6 family, cardiotrophin-1 (CT-1) has been shown to be an important endogenous protector in liver injury. Our study aimed to investigate the role of CT-1 in liver fibrosis in pediatric cholestatic liver disease (PCLD). CT-1 mRNA and protein expression levels were upregulated in PCLD liver biopsy tissues compared with controls. Immunohistochemistry and confocal microscopy of liver sections showed that CT-1 was predominantly expressed by biliary epithelium cells. Serum CT-1 was elevated significantly in the children with PCLD compared with controls. Serum CT-1 levels exhibited a moderate positive correlation with the Scheuer stage of hepatic fibrosis and serum TB levels and a weak correlation with serum ALP levels. In vitro analysis indicated that LX-2 cells preconditioned with CT-1 exhibited significant increments in proliferation and accumulation of extracellular matrix components, while also positively regulating the STAT3 and p38MAPK pathways. In conclusion, biliary epithelium-derived CT-1 may exert a profibrogenic potential in PCLD.

Splenic lymph follicles generate immunoglobulin M-producing B cells in primary biliary cirrhosis

AIM

To reveal the site of immunoglobulin (Ig)M production in primary biliary cirrhosis (PBC) we performed immunohistochemical analysis on spleens collected from patients with PBC.

METHODS

Splenic tissue samples were collected at the time of the autopsy from patients with hepatic failure. Immunostaining for IgM, CD21 and CXCL13 were performed using the splenic tissue samples.

RESULTS

The samples from five out of eight cases with PBC but not in eight cases of chronic hepatitis C virus infection showed accumulation of IgM positive cells in CD21 positive lymph follicles. The CXCL13 positive cells also accumulated in the center of the lymph follicles where the IgM positive cells accumulated.

CONCLUSION

The present results suggest that excess IgM is produced from the spleen of PBC. Furthermore, it was suggested that CXCL13 positive follicular dendritic cells possibly contribute to this process.

The utility of IgG, IgM, and CD138 immunohistochemistry in the evaluation of autoimmune liver diseases

Primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH) present with distinct clinical features. The term "PBC-AIH overlap syndrome (OS)" has been adopted to describe the condition characterized by occurrence of both PBC and AIH, although this clinical entity is difficult to define. This study aimed to assess the utility of IgG, IgM, and CD138 immunohistochemistry in the evaluation of AIH, PBC, and OS. Immunohistochemistry was performed with anti-human IgG, IgM, and CD138 to detect specific plasma cells in the liver. Predominant IgG staining was observed in AIH (85.7 %), while equivocal (46.1 %) or predominant (38.5 %) IgM staining was observed in PBC. In OS, equivocal (20 %) or predominant (80 %) IgG staining was observed. The IgM/IgG ratio was significantly higher in PBC than in AIH or OS (P < 0.005). Histological findings revealed significantly higher IgM expression in PBC at cholangitis activity grades 2-3 compared to those at cholangitis activity grades 0-1. In contrast, a significantly higher IgG expression was observed in PBC at hepatitis activity and fibrosis grades 2-3 compared to those at hepatitis activity and fibrosis grades 0-1. Taken together, periportal plasmacytic infiltrates with variable immunohistochemistry patterns of IgG and IgM expression characterized different autoimmune liver diseases.

Recent advances in diagnosis and treatment of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic autoimmune liver disease characterized by the destruction of small intrahepatic bile ducts and the presence of highly specific serum antimitochondrial antibodies (AMAs). In this article, we will review the clinical, serological and histopathological features of PBC as well as the advances in the diagnosis and differential diagnosis of PBC. In addition, this article systematically describes the advances in the treatment of PBC, and the treatments include ursodeoxycholic acid (UDCA), budesonide, methotrexate (MTX), farnesoid X receptor (FXR) agonists, cyclosporine A, bezafibrate, rituximab, bone marrow-derived mesenchymal stem cell (BM-MSC) transplantation, and liver transplantation. At present, liver transplantation is the only option with known therapeutic benefit for end-stage PBC patients.

Infiltration of inflammatory cells expressing mitochondrial proteins around bile ducts and in biliary epithelial layer may be involved in the pathogenesis in primary biliary cirrhosis

AIMS

Serum antimitochondrial antibodies are characteristic in most patients with primary biliary cirrhosis (PBC); however, the significance of antimitochondrial antibodies in the pathogenesis of PBC remains unclear. We examined the extent and types of mitochondrial protein-expressing inflammatory cells and its association with deregulated autophagy of mitochondria in biliary epithelial lesions in PBC.

METHODS

We examined the expression of pyruvate dehydrogenase complex-E2 component and a mitochondrial protein cytochrome c oxidase, subunit I in inflammatory cells in livers taken from patients with PBC (n=35) and control livers (n=64) including primary sclerosing cholangitis. Mitochondrial protein-expressing inflammatory cells were characterised by double immunofluorescence with surface markers.

RESULTS

Infiltration of mitochondrial protein-expressing inflammatory cells was mainly observed in portal tracts and in the biliary epithelial layer and around the damaged small bile ducts in PBC. The extent of infiltration in portal tracts was significantly higher in PBC and early stage of chronic viral hepatitis than normal livers. The extent of infiltration around bile ducts and in biliary epithelial layer was significantly higher in early stage of PBC than control livers. Mitochondrial protein-expressing inflammatory cells included (1) CD68 and/or myeloperoxidase -positive monocytes/macrophages and (2) CD79a, CD38, CD138, IgM-positive and/or IgG-positive plasma cells. Colocalised expression of pyruvate dehydrogenase complex-E2 component and autophagy marker light chain 3β was observed in the inflammatory cells.

CONCLUSIONS

Mitochondrial protein-expressing inflammatory cells infiltrating around the damaged bile ducts and in biliary epithelial layers may be closely associated with the pathogenesis of bile duct lesion in PBC.

Anti-CD40 ligand monoclonal antibody delays the progression of murine autoimmune cholangitis

While there have been significant advances in our understanding of the autoimmune responses and the molecular nature of the target autoantigens in primary biliary cirrhosis (PBC), unfortunately these data have yet to be translated into new therapeutic agents. We have taken advantage of a unique murine model of autoimmune cholangitis in which mice expressing a dominant negative form of transforming growth factor β receptor II (dnTGFβRII), under the control of the CD4 promoter, develop an intense autoimmune cholangitis associated with serological features similar to human PBC. CD40-CD40 ligand (CD40L) is a major receptor-ligand pair that provides key signals between cells of the adaptive immune system, prompting us to determine the therapeutic potential of treating autoimmune cholangitis with anti-CD40L antibody (anti-CD40L; MR-1). Four-week-old dnTGFβRII mice were injected intraperitoneally with either anti-CD40L or control immunoglobulin (Ig)G at days 0, 2, 4 and 7 and then weekly until 12 or 24 weeks of age and monitored for the progress of serological and histological features of PBC, including rigorous definition of liver cellular infiltrates and cytokine production. Administration of anti-CD40L reduced liver inflammation significantly to 12 weeks of age. In addition, anti-CD40L initially lowered the levels of anti-mitochondrial autoantibodies (AMA), but these reductions were not sustained. These data indicate that anti-CD40L delays autoimmune cholangitis, but the effect wanes over time. Further dissection of the mechanisms involved, and defining the events that lead to the reduction in therapeutic effectiveness will be critical to determining whether such efforts can be applied to PBC.

Diagnostic and clinical significance of anti-centromere antibodies in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune disease of the liver characterised by biochemical evidence of cholestasis, elevated alkaline phosphatase levels and the presence of the highly disease specific anti-mitochondrial autoantibodies. Extra-hepatic autoimmune manifestations are common, including rheumatic disorders, such as systemic sclerosis (SSc). Notably, PBC is the most frequent autoimmune liver disease in SSc patients. Based on skin lesion extension, two major SSc disease subgroups are recognised: limited cutaneous SSc (lSSc) and diffuse cutaneous SSc. Anti-centromere antibody (ACA) positivity is highly characteristic of SSc, with up to 90% prevalence in lSSc patients. ACA has also been found in up to 30% of PBC patients and 80% of patients with a PBC/SSc overlap syndrome. The diagnostic and clinical significance of ACA positivity in patients with PBC without SSc has recently been under investigation, with several studies highlighting links to severe bile duct injury and portal hypertension. This review discusses the diagnostic and clinical relevance of ACA in patients with PBC, with or without SSc.

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

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

Human intrahepatic biliary epithelial cells engulf blebs from their apoptotic peers

The phagocytic clearance of apoptotic cells is critical for tissue homeostasis; a number of non-professional phagocytic cells, including epithelial cells, can both take up and process apoptotic bodies, including the release of anti-inflammatory mediators. These observations are particularly important in the case of human intrahepatic biliary cells (HiBEC), because such cells are themselves a target of destruction in primary biliary cirrhosis, the human autoimmune disease. To address the apoptotic ability of HiBECs, we have focused on their ability to phagocytize apoptotic blebs from autologous HiBECs. In this study we report that HiBEC cells demonstrate phagocytic function from autologous HiBEC peers accompanied by up-regulation of the chemokines CCL2 [monocyte chemotactic protein-1 (MCP-1)] and CXCL8 [interleukin (IL)-8]. In particular, HiBEC cells express the phagocytosis-related receptor phosphatidylserine receptors (PSR), implying that HiBECs function through the 'eat-me' signal phosphatidylserine expressed by apoptotic cells. Indeed, although HiBEC cells acquire antigen-presenting cell (APC) function, they do not change the expression of classic APC function surface markers after engulfment of blebs, both with and without the presence of Toll-like receptor (TLR) stimulation. These results are important not only for understanding of the normal physiological function of HiBECs, but also explain the inflammatory potential and reduced clearance of HiBEC cells following the inflammatory cascade in primary biliary cirrhosis.

Recent advances in understanding the pathogenesis of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic autoimmune liver disease characterized by the destruction of small intrahepatic bile ducts and the presence of highly specific serum antimitochondrial antibodies (AMAs). The human leukocyte antigen (HLA) gene has been proved to have strongest association with PBC susceptibility, and non-HLA genes, including IL12A, IL12RB2, STAT4, IRF5-TNPO3, ORMDL3/IKZF3, MMEL1, SPIB, CTLA-4, FCRL3 and A2BP1, are also closely associated with PBC susceptibility. Four AMAs including anti-M2, anti-M4, anti-M8 and anti-M9, and antinuclear antibodies (ANAs), such as antinuclear dot antibodies (SP100, PML, NDP52, SP140), antinuclear pore antibodies (gp210, p62), antinuclear envelope antibodies (Lamin and Lamin B receptor), and anti-centromere antibodies, may also be involved in the pathogenesis of PBC. The imbalance between Th17 cells and regulatory T lymphocytes (Treg) may also play an important role in the pathogenesis of PBC. In addition, senescence, autophagy, apoptosis of biliary epithelial cells (BECs), and environmental factors, such as Epstein-Barr virus (EBV) infection and smoking, may also contribute to the pathogenesis of PBC. Understanding of the mechanisms responsible for the pathogenesis of PBC has important implications for the treatment of PBC.

Xenobiotics and autoimmunity: does acetaminophen cause primary biliary cirrhosis?

The serologic hallmark of primary biliary cirrhosis (PBC) is the presence of antimitochondrial autoantibodies (AMAs) directed against the E2 subunit of the pyruvate dehydrogenase complex (PDC-E2). The PBC-related autoepitope of PDC-E2 contains lipoic acid, and previous work has demonstrated that mimics of lipoic acid following immunization of mice lead to a PBC-like disease. Furthermore, approximately one-third of patients who have ingested excessive amounts of acetaminophen (paracetamol) develop AMA of the same specificity as patients with PBC. Quantitative structure-activity relationship (QSAR) data indicates that acetaminophen metabolites are particularly immunoreactive with AMA, and we submit that in genetically susceptible hosts, electrophilic modification of lipoic acid in PDC-E2 by acetaminophen or similar drugs can facilitate a loss of tolerance and lead to the development of PBC.

Tuberculosis Is Not a Risk Factor for Primary Biliary Cirrhosis: A Review of the Literature

Primary biliary cirrhosis (PBC) is a progressive cholestatic liver disease characterised serologically by cholestasis and the presence of high-titre antimitochondrial antibodies, and histologically by chronic nonsuppurative cholangitis and granulomata. As PBC is a granulomatous disease andMycobacterium tuberculosisis the most frequent cause of granulomata, a causal relation between tuberculosis and PBC has been suggested. Attempts to find serological evidence of PBC-specific autoantibodies such as AMA have been made and, conversely, granulomatous livers from patients with PBC have been investigated for molecular evidence ofMycobacterium tuberculosis. This paper discusses in detail the reported data in support or against an association betweenMycobacterium tuberculosisinfection and PBC. We discuss the immunological and microbiological data exploring the association of PBC with exposure toMycobacterium tuberculosis. We also discuss the findings of large epidemiologic studies investigating the association of PBC with preexistent or concomitant disorders and the relevance of these findings with tuberculosis. Genome-wide association studies in patients with tuberculosis as well as in patients with PBC provide conclusive hints regarding the assumed association between exposure to this mycobacterium and the induction of PBC. Analysis of these data suggest thatMycobacterium tuberculosisis an unlikely infectious trigger of PBC.