Primary biliary cirrhosis-related autoantibodies in a large cohort of italian patients with systemic sclerosis

Idiopathic and connective tissue disease-associated pulmonary arterial hypertension (PAH): Similarities, differences and the role of autoimmunity

Pre-capillary pulmonary arterial hypertension (PAH) is hemodynamically characterized by a mean pulmonary arterial pressure (mPAP) ≥ 20 mmHg, pulmonary capillary wedge pressure (PAWP) ≤15 mmHg and pulmonary vascular resistance (PVR) > 2. PAH is classified in six clinical subgroups, including idiopathic PAH (IPAH) and PAH associated to connective tissue diseases (CTD-PAH), that will be the main object of this review. The aim is to compare these two PAH subgroups in terms of epidemiology, histological and pathogenic findings in an attempt to define disease-specific features, including autoimmunity, that may explain the heterogeneity of response to therapy between IPAH and CTD-PAH.

Diagnostic value of anti-mitochondrial antibody in patients with primary biliary cholangitis: A systemic review and meta-analysis

BACKGROUND

Anti-mitochondrial antibodies (AMA) and the M2 subtype are considered serological hallmarks in the diagnosis of primary biliary cholangitis (PBC). However, these autoantibodies may be undetectable in some patients. This meta-analysis aimed to evaluate the diagnostic accuracy of serum AMA and M2 for PBC.

METHODS

We systematically searched PubMed, Embase, Web of Science, and the Cochrane Library for relevant studies. Pooled sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), and diagnostic odds ratio (DOR) were calculated using a random-effects model. We also constructed hierarchical summary receiver operating characteristic curves and calculated the area under the curve values.

RESULTS

Our meta-analysis included 28 studies, of which 24 examined the diagnostic accuracy of AMA for PBC. Pooled sensitivity and specificity of AMA were 84% (95% confidence intervals [CI] 77-90%) and 98% (96-99%), respectively. Pooled LR+, LR-, and DOR were 42.2 (22.1-80.5), 0.16 (0.11-0.24), and 262 (114-601), respectively. Sixteen studies explored the diagnostic value of the M2 subtype, demonstrating pooled sensitivity and specificity of 89% (81-94%) and 96% (93-98%), respectively. Pooled LR+, LR-, and DOR were 20.3 (8.0-51.1), 0.12 (0.05-0.26), and 169 (41-706), respectively. The hierarchical summary receiver operating characteristic curves for both of serum AMA and M2 subtype lie closer to the upper left corner of the plot with area under the curve values of 0.98 (95% CI = 0.96-0.99) and 0.98 (95% CI = 0.96-0.99) respectively.

CONCLUSION

This meta-analysis provides evidence affirming the utility of AMA and M2 as sensitive and specific serological hallmarks that can facilitate early screening and diagnosis of PBC.

Systemic sclerosis and primary biliary cholangitis: Longitudinal data to determine the outcomes

Background

Several studies described the cross-sectional characteristics of systemic sclerosis patients and coexisting primary biliary cholangitis, but longitudinal prognostic data are lacking.

Aims

To describe the systemic sclerosis-primary biliary cholangitis phenotype, including baseline characteristics and outcomes.

Methods

We performed a multicentre the European Scleroderma Trials and Research Group study of systemic sclerosis patients with primary biliary cholangitis or with primary biliary cholangitis-specific antibodies, matched with systemic sclerosis controls free from hepatobiliary involvement matched for disease duration and cutaneous subset. Data were recorded at baseline and at the last available visit.

Results

A total of 261 patients were enrolled (115 primary biliary cholangitis-systemic sclerosis, 161 systemic sclerosis). At baseline, systemic sclerosis-primary biliary cholangitis patients had a higher prevalence of anti-centromere antibodies (p = 0.0023) and a lower prevalence of complete absence of digital ulcers. The milder vascular involvement was confirmed at follow-up when crucial differences emerged in the percentage of patients experiencing digital ulcers; a significantly higher number of patients who never experienced digital ulcers were observed among primary biliary cholangitis-systemic sclerosis patients (p = 0.0015). Moreover, a greater incidence of pulmonary arterial hypertension (p < 0.001) and of conduction blocks (p = 0.0256) was observed in systemic sclerosis patients without primary biliary cholangitis. Patients with primary biliary cholangitis had higher levels of liver enzymes at baseline than systemic sclerosis patients; a significant decrease in liver enzymes was observed at follow-up. Out of 18 patients with cholangitis, one received a liver transplant at follow-up.

Conclusion

Our data show that systemic sclerosis-primary biliary cholangitis exhibit a mild systemic sclerosis and primary biliary cholangitis phenotype with outcomes being in general favourable.

Systemic sclerosis and primary biliary cholangitis share an antibody population with identical specificity

Anti-centromere (ACA) and antimitochondrial antibodies (AMA) are specific for limited-cutaneous systemic sclerosis (lcSSc) and primary biliary cholangitis (PBC), respectively, and can coexist in up to 25 and 30% of SSc and PBC patients. Here, we evaluated whether anti-centromeric protein A (CENP-A) antibodies cross-react with mitochondrial antigens. To this end, sera from two lcSSc patients (pt1 and pt4), one of them (pt4) also affected by PBC, were used as the source of ACA, previously shown to recognize different groups of amino acids (motifs) in the CENP-A region spanning amino acids 1-17 (Ap1-17). Pt1 and pt4 Ap1-17-specific IgG were purified by affinity-chromatography on insolubilized Ap1-17-peptide column and tested by western blotting with nuclear and cytoplasmic protein extract from HeLa cells. Immunoreactive proteins were identified by mass spectrometry and validated by immunodot. The results showed that affinity-purified SSc/PBC pt4 anti-Ap1-17 and not SSc pt1 anti-Ap1-17 Ab, specifically cross-reacted with the E2 component of the mitochondrial pyruvate dehydrogenase complex (PDC-E2), the major mitochondrial autoantigen in PBC. Sequence homology analysis indicated that the motif A-x-x-P-x-A-P recognized by pt4 anti-Ap1-17 IgG and shared by CENP-A and PDC-E2, is also expressed by some members of the Human Herpesvirus family, suggesting that they may trigger the production of these cross-reacting antibodies.

Clinical Relevance of Liver Involvement in the Clinical Course of Systemic Sclerosis

Liver involvement in systemic sclerosis (SSc) is rare. We evaluated the prevalence of liver fibrosis and hepatic autoimmunity in SSc patients in a retrospective observational cohort (97 SSc or mixed connective tissue disease with sclerodermic manifestations patients undergoing transient elastography, evaluating liver stiffness (LS) and controlled attenuation parameter (CAP), due to clinical indications along with biochemistry assessments and major antibodies associated to liver autoimmunity). Among them, 11 had LS ≥ 7.5 kPa and 5 showed an LS compatible with cirrhosis (LS ≥ 12.5 kPa). Predictors of LS ≥ 7.5 fibrosis were alcohol consumption (>14 or >7 alcoholic units/week for men and women, respectively), waist circumference (>102 or >88 cm for men and women, respectively), elevated alkaline phosphatase, and anti-La and anti-mitochondrial antibody (AMA) positivity. Six patients had CAP values compatible with severe steatosis (≥280 dB/m). Waist circumference, body mass index and diabetes mellitus were significant predictors of steatosis. Out of 97 patients, 19 were positive for AMA, 4 for anti-Sp100, 1 for anti-Gp210 and 7 were diagnosed with primary biliary cholangitis. Among SSc patients, hepatic fibrosis biomarkers and AMA prevalence are relatively high, suggesting the opportunity of performing a transient elastography and a screening for hepatic autoimmunity at diagnosis and/or during disease progression.

Antimitochondrial Antibodies: from Bench to Bedside

Anti-mitochondrial antibodies (AMA) are directed against the E2 subunits of the 2-oxo acid dehydrogenase complexes (PDC-E2) and are the typical biomarkers of primary biliary cholangitis (PBC), being present in 90-95% of patients, with increasing sensitivity at increasing titers. Albeit being highly specific for PBC diagnosis, AMA can be detected in less than 1% of healthy subjects, and thus the management subjects with no sign or symptom of liver disease is still a challenge and data concerning clinical risk of developing PBC in this subgroup of patients are controversial. Moreover, AMA can also be detected in patients affected by overlap syndrome, as well as hepatic diseases (i.e., NASH and viral hepatitis), while the association with autoimmune diseases, in particular Sjögren's syndrome, systemic sclerosis, and systemic lupus erythematosus, is well established. Furthermore, new associations are being identified with inflammatory myositis and heart disease. AMA are directed towards the pyruvate dehydrogenase multi enzyme complex (PDC-E2) subunit, which represents an epithelial specific autoantigen for PBC. This review focuses on the main characteristics of AMA, their association with autoimmune diseases and liver diseases.

Quantification of mitochondrial DNA damage and copy number in circulating blood of patients with systemic sclerosis by a qPCR-based assay

Background

Although not fully understood, oxidative stress has been implicated in the pathogenesis of different autoimmune diseases such as systemic sclerosis. Accumulating evidence indicates that oxidative stress can induce mitochondrial DNA (mtDNA) damage and variations in mtDNA copy number (mtDNAcn).

Objective

The aim of this study was to explore mtDNAcn and oxidative DNA damage byproducts in peripheral blood of patients with systemic sclerosis and healthy controls.

Methods

Forty six patients with systemic sclerosis and forty nine healthy subjects were studied. Quantitative real-time PCR used to measure the relative mtDNAcn and the oxidative damage (oxidized purines) of each sample.

Results

The mean mtDNAcn was lower in patients with systemic sclerosis than in healthy controls whereas the degree of mtDNA damage was significantly higher in cases as compared to controls. Moreover, there was a negative correlation between mtDNAcn and oxidative DNA damage.

Study limitations

The lack of simultaneous analysis and quantification of DNA oxidative damage markers in serum or urine of patients with systemic sclerosis and healthy controls.

Conclusion

These data suggest that alteration in mtDNAcn and increased oxidative DNA damage may be involved in the pathogenesis of systemic sclerosis.

Evaluation of the primary biliary cholangitis-related serologic profile in a large cohort of Belgian systemic sclerosis patients

Background

Systemic sclerosis (SSc) and primary biliary cholangitis (PBC) are autoimmune diseases that may occur concomitantly and are both strongly associated with disease-specific autoantibodies. This study investigated the prevalence and fine specificity of PBC-specific serology (PBC-Ab) and associations with the SSc-subtypes and SSc-specific antibodies as well as the association with cholestatic liver enzymes. Furthermore, three different techniques for the detection of PBC-Ab were compared.

Methods

Serum of 184 Belgian SSc patients with a known SSc-antibody profile, was analyzed for PBC-Ab (antimitochondrial antibodies [AMA], anti-Gp210, anti-Sp100 and anti-PML) using indirect immunofluorescence (IIF) analysis on human epithelioma-2000 (HEp-2000) cells (ANA-IIF, Immunoconcepts) and liver-kidney-stomach tissue sections (IIF-LKS) (Menarini), and a line immunoblot (LB) (EuroImmun). Alkaline phosphatase/γ-glutamyl transferase (ALP/GGT) were evaluated at time of first sampling (t0) and after 3 years of follow-up (t3).

Results

PBC-Ab were present in 13% of patients and significantly correlated with centromere antibodies (anti-CENP-B), but not correlated with the limited cutaneous SSc subgroup (lcSSc). The most frequent reactivities were AMA (11%, with 9% AMA-M2) and Sp-100 antibodies (5%), showing a major overlap. There was no relevant association between the presence of PBC-Ab and ALP or GGT elevation at t0 nor at t3. Detection of AMA with IIF-LKS is comparable to LB. ANA-IIF screening was less sensitive compared to LB.

Conclusions

A wide range of PBC-Ab is detectable in SSc in the absence of cholestatic liver enzyme elevations, even after 3 years of follow-up. However, as these antibodies may precede PBC-disease up to 10 years further prospective follow-up of our cohort will be necessary.

Systemic sclerosis and primary biliary cholangitis: An overlapping entity?

Systemic sclerosis (SSc) is a complex autoimmune disease that may lead to skin and internal organ fibrosis. Based on skin involvement, two subsets of the disease are recognized (limited cutaneous SSc and diffuse cutaneous SSc). The new 2013 American College of Rheumatology/European League against Rheumatism classification criteria allow to identify SSc patients at the early stage of the disease that allows new research avenues. The aetiology of the disease is still unknown, but it has an important autoimmune basis and its association with other autoimmune diseases has been reproducibly reported. Among them, primary biliary cholangitis is considered the most common liver disease in SSc. The aim of this review is to provide an overview on recent findings about SSc associated to primary biliary cholangitis. Although the aetiology of the two diseases is still unknown, data suggest that these two disorders share the expression of fibrogenic cytokines, involved both in generation and function of T lymphocytes subpopulation (Th17 cells) and regulatory T lymphocytes. In addition, the relationships between SSc and primary biliary cholangitis may be closer as suggested by the presence of primary biliary cholangitis-specific antibodies in SSc patients and vice versa. Recent findings confirm a prevalence of overt primary biliary cholangitis in about 2% of SSc population, in particular in patients with limited cutaneous SSc and positive anticentromere antibodies. The prevalence increases if also patients with only primary biliary cholangitis-specific antibodies are considered. Data regarding SSc prevalence in primary biliary cholangitis patients have also been recently clarified. Altogether, stimulating results are moving the field forward regarding the relationships of these two autoimmune and fibrotic disorders that may belong to an overlapping entity.

Hepatobiliary involvement in systemic sclerosis and the cutaneous subsets: Characteristics and survival of patients from the Spanish RESCLE Registry

OBJECTIVE

To assess the prevalence and causes of hepatobiliary involvement (HBI) in systemic sclerosis (SSc), to investigate the clinical characteristics and prognosis of SSc patients with HBI (SSc-HBI) and without HBI (SSc-non-HBI), and to compare both groups according to the cutaneous SSc subsets.

METHODS

In all, 1572 SSc patients were collected in the RESCLE registry up to January 2015, and all hepatobiliary disturbances were recorded. We investigated the HBI-related characteristics and survival from the entire SSc cohort and according to the following cutaneous subsets: diffuse cutaneous SSc (dcSSc), limited cutaneous SSc (lcSSc), and SSc sine scleroderma (ssSSc).

RESULTS

Out of 1572, 118 (7.5%) patients had HBI. Primary biliary cholangitis (PBC) was largely the main cause (n = 67, 4.3%), followed by autoimmune hepatitis (n = 19, 1.2%), and anti-mitochondrial negative PBC (n = 6, 0.4%). Other causes of HBI were as follows: secondary liver diseases (n = 11, 0.7%), SSc-related HBI (n = 7, 0.4%), nodular regenerative hyperplasia (n = 3, 0.2%), liver cirrhosis (n = 3, 0.2%), and HBI of unknown origin (n = 2, 0.1%). In multivariate analysis, HBI was independently associated to lesser risk of dcSSc (5.1% vs. 24.4%), and higher frequency of calcinosis (26% vs. 18%), left ventricular diastolic dysfunction (46% vs. 27%), sicca syndrome (51% vs. 29%), and anti-centromere antibodies (ACA, 73% vs. 44%). According to the cutaneous subsets, HBI was associated (1) in lcSSc, to longer time from SSc onset to diagnosis (10.8 ± 12.5 vs. 7.2 ± 9.3 years), sicca syndrome (54% vs. 33%), and ACA (80% vs. 56%); (2) in ssSSc, to sicca syndrome (44% vs. 19%), and (3) in dcSSc, no associations were found. HBI was the cause of death in 2.3% patients but the cumulative survival according to the presence or absence of HBI showed no differences.

CONCLUSIONS

HBI prevalence in SSc is 7.5% and dcSSc is the least involved subset. PBC is the main cause of HBI. Patients with SSc-HBI exhibited specific clinical and immunologic profile. Survival is similar for SSc patients with HBI.

Detection of anti-mitochondrial antibodies by immunoprecipitation in patients with systemic sclerosis

OBJECTIVE

To describe a new immunoprecipitation pattern identified in Italian patients affected by systemic sclerosis (SSc), corresponding to the pyruvate dehydrogenase antigen complex recognized by anti-mitochondrial antibodies (AMA) in primary biliary cholangitis (PBC).

METHODS

Autoantibodies in sera from 85 patients with SSc were tested by protein- and RNA-immunoprecipitation. Immunoprecipitation-Western blot was used to determine the identified proteins, and medical records re-evaluated for liver function tests and PBC.

RESULTS

In 13/85 (15%) SSc sera, a unique set of 75-50-40-34kD proteins that had not been previously reported, was noted. The four proteins were identified as the proteins X/E3BP, E1α, E1β, and E2/E3 of the pyruvate dehydrogenase antigen complex by immunoprecipitation-Western blot. From clinical record evaluation, 9/13 (69%) SSc patients with this new pattern were positive for AMA by routine indirect immunofluorescence, and 7/13 (54%) had a diagnosis of PBC, while 4/13 (31%) manifested no biochemical signs of cholestasis. Twelve of 13 patients with SSc and AMA by immunoprecipitation have a limited cutaneous form of SSc and anti-centromere antibodies.

CONCLUSIONS

We describe a pattern of 4 proteins in 15% of SSc patients, identified for the first time by protein-immunoprecipitation. This pattern corresponds to serum AMA against the pyruvate dehydrogenase antigen complex and it must be considered in the interpretation of protein-immunoprecipitation results.

Review article: pathogenesis and clinical manifestations of gastrointestinal involvement in systemic sclerosis

BACKGROUND

Gastrointestinal tract (GIT) involvement is a common cause of debilitating symptoms in patients with systemic sclerosis (SSc). There are no disease modifying therapies for this condition and the treatment remains symptomatic, largely owing to the lack of a clear understanding of its pathogenesis.

AIMS

To investigate novel aspects of the pathogenesis of gastrointestinal involvement in SSc. To summarise existing knowledge regarding the cardinal clinical gastrointestinal manifestations of SSc and its pathogenesis, emphasising recent investigations that may be valuable in identifying potentially novel therapeutic targets.

METHODS

Electronic (PubMed/Medline) and manual Google search.

RESULTS

The GIT is the most common internal organ involved in SSc. Any part of the GIT from the mouth to the anus can be affected. There is substantial variability in clinical manifestations and disease course and symptoms are nonspecific and overlapping for a particular anatomical site. Gastrointestinal involvement can occur in the absence of cutaneous disease. Up to 8% of SSc patients develop severe GIT symptoms. This subset of patients display increased mortality with only 15% survival at 9 years. Dysmotiity of the GIT causes the majority of symptoms. Recent investigations have identified a novel mechanism in the pathogenesis of GIT dysmotility mediated by functional anti-muscarinic receptor autoantibodies.

CONCLUSIONS

Despite extensive investigation, the pathogenesis of gastrointestinal involvement in systemic sclerosis remains elusive. Although treatment currently remains symptomatic, an improved understanding of novel pathogenic mechanisms may allow the development of potentially highly effective approaches including intravenous immunoglobulin and microRNA based therapeutic interventions.

The management of autoimmunity in patients with cholestatic liver diseases

Cholestatic liver diseases are rare diseases that often lead to cirrhosis and its consequent complications. In addition to liver-related morbidity, patients with cholestatic liver diseases often suffer from autoimmune diseases that affect several organs and tissues. The robust and efficient data collection and collaboration between hepatologists and rheumatologists have led to significant advancements in understanding the relationship between the cholestatic liver diseases and associated autoimmune diseases. In this paper, we discuss the cholestatic liver diseases (primary biliary cirrhosis, primary sclerosing cholangitis and immunoglobulin G4 associated cholangitis) and associated autoimmune diseases.

Evaluation and management of gastrointestinal manifestations in scleroderma

PURPOSE OF REVIEW

The gastrointestinal tract is the most common extra-cutaneous organ system involved with systemic sclerosis (SSc) affecting approximately 90% of patients. This review summarizes the recent advances in the evaluation and management of gastrointestinal manifestations of SSc.

RECENT FINDINGS

There is a growing body of evidence that uncontrolled GERD can play a significant role in the pathogenesis of SSc-associated interstitial lung disease. Newer forms of management of Barrett esophagus are showing significant promise as potentially curative therapy. Gastric antral vascular ectasias have strongly been associated with the presence of RNA polymerase III antibody. Newer technologies have advanced the assessment of gastrointestinal dysmotility in SSc. Evidence of probiotic use for the treatment of gastrointestinal complications is emerging. The UCLA SCTC GIT 2.0 questionnaire is being increasingly accepted by the SSc experts as a validated instrument for evaluation of patient-reported outcomes involving the gastrointestinal tract.

SUMMARY

Our knowledge of the complex pathogenesis of gastrointestinal manifestations of SSc has expanded substantially in the last few decades. There has also been considerable technological progress in the evaluation of these manifestations. Patient care is being optimized by close collaboration of rheumatologists and gastroenterologists, leading to a more coordinated approach in the management of these complications.

The accuracy of the anti-mitochondrial antibody and the M2 subtype test for diagnosis of primary biliary cirrhosis: a meta-analysis

The aim of this study was to evaluate the diagnostic value of anti-mitochondrial antibodies (AMAs) and/or the M2 subtype (AMA-M2) in patients with primary biliary cirrhosis (PBC). AMA/AMA-M2 data were obtained by searching electronic databases. Studies showing AMA/AMA-M2 results in patients with PBC and control groups with other liver diseases or healthy livers were included. The quality of the involved studies was assessed using the QUADAS tool. The pooled sensitivity and specificity were calculated, and stratified analysis was performed according to possible heterogeneity sources. The pooled AMA (all methods) sensitivity and specificity were 84.5% (95% confidence interval (CI) 83.3%-85.6%) and 97.8% (95% CI 97.6%-98.0%), respectively. The positive and negative likelihood ratios were 25.201 (95% CI 17.583-36.118) and 0.162 (95% CI 0.131-0.199), respectively. The current evidence suggests that AMA and AMA-M2 show favorable accuracy for the diagnosis of PBC with high specificity and sensitivity. AMA is a better and more comprehensive marker than AMA-M2. The accuracy established in this meta-analysis is based on clinical studies using patient cohorts from different ethnicities.

Coherent somatic mutation in autoimmune disease

BACKGROUND

Many aspects of autoimmune disease are not well understood, including the specificities of autoimmune targets, and patterns of co-morbidity and cross-heritability across diseases. Prior work has provided evidence that somatic mutation caused by gene conversion and deletion at segmentally duplicated loci is relevant to several diseases. Simple tandem repeat (STR) sequence is highly mutable, both somatically and in the germ-line, and somatic STR mutations are observed under inflammation.

RESULTS

Protein-coding genes spanning STRs having markers of mutability, including germ-line variability, high total length, repeat count and/or repeat similarity, are evaluated in the context of autoimmunity. For the initiation of autoimmune disease, antigens whose autoantibodies are the first observed in a disease, termed primary autoantigens, are informative. Three primary autoantigens, thyroid peroxidase (TPO), phogrin (PTPRN2) and filaggrin (FLG), include STRs that are among the eleven longest STRs spanned by protein-coding genes. This association of primary autoantigens with long STR sequence is highly significant (p<3.0x10(-7)). Long STRs occur within twenty genes that are associated with sixteen common autoimmune diseases and atherosclerosis. The repeat within the TTC34 gene is an outlier in terms of length and a link with systemic lupus erythematosus is proposed.

CONCLUSIONS

The results support the hypothesis that many autoimmune diseases are triggered by immune responses to proteins whose DNA sequence mutates somatically in a coherent, consistent fashion. Other autoimmune diseases may be caused by coherent somatic mutations in immune cells. The coherent somatic mutation hypothesis has the potential to be a comprehensive explanation for the initiation of many autoimmune diseases.

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

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

Epitope-specific anti-nuclear antibodies are expressed in a mouse model of primary biliary cirrhosis and are cytokine-dependent

Although the hallmark of primary biliary cirrhosis (PBC) is the presence of anti-mitochondrial antibodies (AMA), a significant number of patients have anti-nuclear antibodies (ANA) directed primarily against two nuclear proteins, gp210 and sp100. In PBC, there are considerable data on the specificity of these anti-nuclear antibodies as well as suggestive evidence that antibodies to gp210 predict a poor outcome. However, a further understanding of the significance of these autoantibodies has been hampered by limitations in accessing human subjects in a preclinical or early asymptomatic stage. To overcome this limitation, we have taken advantage of transgenic mice with abrogated transforming growth factor-β signalling in T cells (dnTGF-βRII) that develop histological features of PBC as well as the same AMA specificity. We studied these mice for serum ANA, including specific autoantibodies against gp210 and sp100. We further examined sera from dnTGF-βRII mice with concurrent deletions of the genes encoding interleukin (IL)-12p35, IL-12p40, IL-23p19, IL-17, IL-6, interferon (IFN)-γ or tumour necrosis factor (TNF)-α. Sera from all the dnTGF-βRII mouse lines contained antibodies against gp210 and sp100. Of significance, mice with germline deletions of the genes encoding IL-12p40, IL-23p19, IL-17, IL-6 and TNF-α had significantly lower titres of anti-gp210 antibodies. These results provide a platform to dissect the mechanisms of gp210 and sp100 autoantibody production in dnTGF-βRII mice as well as to study the possible role of ANA in the pathophysiology of PBC.

Autoimmune hepatitis/primary biliary cirrhosis overlap syndrome and associated extrahepatic autoimmune diseases

AIM

To assess the prevalence of concurrent extrahepatic autoimmune diseases in patients with autoimmune hepatitis (AIH)/primary biliary cirrhosis (PBC) overlap syndrome and applicability of the 'mosaic of autoimmunity' in these patients.

METHODS

The medical data of 71 AIH/PBC overlap patients were evaluated for associated autoimmune diseases.

RESULTS

In the study population, 31 (43.6%) patients had extrahepatic autoimmune diseases, including autoimmune thyroid diseases (13 patients, 18.3%), Sjögren syndrome (six patients, 8.4%), celiac disease (three patients, 4.2%), psoriasis (three patients, 4.2%), rheumatoid arthritis (three patients, 4.2%), vitiligo (two patients, 2.8%), and systemic lupus erythematosus (two patients, 2.8%). Autoimmune hemolytic anemia, antiphospholipid syndrome, multiple sclerosis, membranous glomerulonephritis, sarcoidosis, systemic sclerosis, and temporal arteritis were identified in one patient each (1.4%). A total of 181 autoimmune disease diagnoses were found in our patients. Among them, 40 patients (56.4%) had two, 23 (32.3%) had three, and eight (11.3%) had four diagnosed autoimmune diseases.

CONCLUSION

A large number of autoimmune diseases were associated with AIH/PBC overlap patients. Therefore, extended screening for existing autoimmune diseases during the routine assessment of these patients is recommended. Our study suggests that the concept of 'mosaic of autoimmunity' is a valid clinical entity that is applicable to patients with AIH/PBC overlap syndrome.