Large-scale characterization study of patients with antimitochondrial antibodies but nonestablished primary biliary cholangitis

Inflammation: Cause or consequence of chronic cholestatic liver injury

Cholestasis is a result of obstruction of the biliary tracts. It is a common cause of liver pathology after exposure to toxic xenobiotics and during numerous other liver diseases. Accumulation of bile acids in the liver is thought to be a major driver of liver injury during cholestasis and can lead to eventual liver fibrosis and cirrhosis. As such, current therapy in the field of chronic liver diseases with prominent cholestasis relies heavily on increasing choleresis to limit accumulation of bile acids. Many of these same diseases also present with autoimmunity before the onset of cholestasis though, indicating the inflammation may be an initiating component of the pathology. Moreover, cytotoxic inflammatory mediators accumulate during cholestasis and can propagate liver injury. Anti-inflammatory biologics and small molecules have largely failed clinical trials in these diseases though and as such, targeting inflammation as a means to address cholestatic liver injury remains debatable. The purpose of this review is to understand the different roles that inflammation can play during cholestatic liver injury and attempt to define how new therapeutic targets that limit or control inflammation may be beneficial for patients with chronic cholestatic liver disease.

Evolving liver inflammation in biochemically normal individuals with anti-mitochondria antibodies

Background

Anti-mitochondria autoantibodies (AMA) occur in > 95% primary biliary cholangitis (PBC) patients. Biochemically normal AMA-positive (BN/AMA+) individuals, occasionally noticed by indirect immunofluorescence (IIF) on HEp-2 cells and confirmed in AMA-specific assays, may represent early stages of PBC. The Enhanced Liver Fibrosis (ELF) score is a surrogate marker for liver fibrosis. This prospective study investigated the ELF score in BN/AMA+ individuals and PBC patients, considering autoantibody avidity and serum levels along the years.

Methods

327 samples from 35 PBC and 59 BN/AMA+ were prospectively obtained in average 3.83 (range 0.50-7.40) years apart. Samples were tested by IIF on rat-kidney (IIF-AMA), western-blot for AMA (WB-AMA), and ELISA for antibodies against pyruvate-dehydrogenase (PDC-E2), gp210, sp100 and CENP-A/B. Anti-PDC-E2 avidity was determined by 6 M urea-elution ELISA. Alkaline phosphatase (ALP), gamma glutamyl transferase (ɣGT) and ELF score were measured by automated methods.

Results

Along the follow-up period BN/AMA+ subjects and PBC patients presented significant increase in serum anti-PDC-E2 (mean 10.45% and 8.86% per year; respectively), anti-PDC-E2 avidity (3.02% and 4.94%/year) and ELF score (3.24% and 2.71%/year). IIF-AMA and ɣGT increased in BN/AMA+ (6.59% and 2.36%) and decreased in PBC (- 4.89%/year and - 3.88%/year). In BN/AMA+ individuals there was positive correlation of ELF with IIF-AMA titer (r = 0.465; p < 0.001) and with anti-PDC-E2 levels (r = 0.239; p < 0.001). Expansion of autoantibody targets along time occurred in 39% BN/AMA+ and 49% PBC patients. The frequency of BN/AMA+ with high probability of having established PBC increased from 7 to 14%.

Conclusions

BN/AMA+ individuals present an orchestrated increase in ELF score and humoral autoimmune response over time, indicating an opportunity for early therapeutic intervention and prevention in autoimmunity.

The challenges of primary biliary cholangitis: What is new and what needs to be done

Primary Biliary Cholangitis (PBC) is an uncommon, chronic, cholangiopathy of autoimmune origin and unknown etiology characterized by positive anti-mitochondrial autoantibodies (AMA), female preponderance and progression to cirrhosis if left untreated. The diagnosis is based on AMA- or PBC-specific anti-nuclear antibody (ANA)-positivity in the presence of a cholestatic biochemical profile, histologic confirmation being mandatory only in seronegative cases. First-line treatment is ursodeoxycholic acid (UDCA), which is effective in preventing disease progression in about two thirds of the patients. The only approved second-line treatment is obeticholic acid. This article summarizes the most relevant conclusions of a meeting held in Lugano, Switzerland, from September 23rd-25th 2018, gathering basic and clinical scientists with various background from around the world to discuss the latest advances in PBC research. The meeting was dedicated to Ian Mackay, pioneer in the field of autoimmune liver diseases. The role of liver histology needs to be reconsidered: liver pathology consistent with PBC in AMA-positive individuals without biochemical cholestasis is increasingly reported, raising the question as to whether biochemical cholestasis is a reliable disease marker for both clinical practice and trials. The urgent need for new biomarkers, including more accurate markers of cholestasis, was also widely discussed during the meeting. Moreover, new insights in interactions of bile acids with biliary epithelia in PBC provide solid evidence of a role for impaired epithelial protection against potentially toxic hydrophobic bile acids, raising the fundamental question as to whether this bile acid-induced epithelial damage is the cause or the consequence of the autoimmune attack to the biliary epithelium. Strategies are needed to identify difficult-to-treat patients at an early disease stage, when new therapeutic approaches targeting immunologic pathways, in addition to bile acid-based therapies, may be effective. In conclusion, using interdisciplinary approaches, groundbreaking advances can be expected before long in respect to our understanding of the etiopathogenesis of PBC, with the ultimate aim of improving its treatment.

Variant and Specific Forms of Autoimmune Cholestatic Liver Diseases

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are the main autoimmune cholestatic liver diseases. IgG4-associated sclerosing cholangitis is another distinct immune-mediated cholestatic disorder of unknown aetiology that is frequently associated with autoimmune pancreatitis or other IgG4-related diseases. Although the majority of PBC and PSC patients have a typical presentation, there are common and uncommon important variants or specific subgroups that observed in everyday routine clinical practice. In this updated review, we summarize the published data giving also our own experience on the variants and specific groups of autoimmune cholestatic liver diseases. Actually, we give in detail the underlining difficulties and the rising dilemmas concerning the diagnosis and management of these special conditions in the clinical spectrum of autoimmune cholestatic liver diseases including the IgG4-associated sclerosing cholangitis highlighting also the uncertainties and the potential new eras of the research agenda.

The Prevalence of Anti-Hexokinase-1 and Anti-Kelch-Like 12 Peptide Antibodies in Patients With Primary Biliary Cholangitis Is Similar in Europe and North America: A Large International, Multi-Center Study

Primary biliary cholangitis (PBC), formerly known as primary biliary cirrhosis, is present worldwide. Autoantibodies, in particular anti-mitochondrial antibodies (AMA) detected by indirect immunofluorescence assays or newer solid phase immunoassays can detect most, but not all individuals with PBC. Detection of antibodies to the anti-nuclear antigens sp100 and gp210 can identify additional PBC patients, but some seronegative patients remain, often resulting in delayed diagnosis and treatment. Antibodies to kelch-like 12 (KLHL12) and hexokinase 1 (HK-1) were recently identified as new biomarkers for PBC and notably identify patients who are negative for conventional autoantibodies. To become globally adopted, it is important to validate these new biomarkers in different geographic areas. In the present study we evaluated the prevalence of anti-KLHL12 (measured by a KLHL12-derived peptide referred to as KL-p) and anti-HK-1 antibodies by ELISA at five sites within Europe and North America and demonstrated the presence of these antibodies in patients with PBC in all geographies.

Burden of liver diseases in the world

Liver disease accounts for approximately 2 million deaths per year worldwide, 1 million due to complications of cirrhosis and 1million due to viral hepatitis and hepatocellular carcinoma. Cirrhosis is currently the 11th most common cause of death globally and liver cancer is the 16th leading cause of death; combined, they account for 3.5% of all deaths worldwide. Cirrhosis is within the top 20 causes of disability-adjusted life years and years of life lost, accounting for 1.6% and 2.1% of the worldwide burden. About 2 billion people consume alcohol worldwide and upwards of 75 million are diagnosed with alcohol-use disorders and are at risk of alcohol-associated liver disease. Approximately 2 billion adults are obese or overweight and over 400 million have diabetes; both of which are risk factors for non-alcoholic fatty liver disease and hepatocellular carcinoma. The global prevalence of viral hepatitis remains high, while drug-induced liver injury continues to increase as a major cause of acute hepatitis. Liver transplantation is the second most common solid organ transplantation, yet less than 10% of global transplantation needs are met at current rates. Though these numbers are sobering, they highlight an important opportunity to improve public health given that most causes of liver diseases are preventable.

Primary Biliary Cholangitis and Autoimmune Hepatitis

Primary biliary cholangitis and autoimmune hepatitis are common autoimmune diseases of the liver. Both have typical clinical presentations, including certain autoantibodies on serologic testing. Histologic features are also often typical: primary biliary cholangitis shows bile duct destruction (sometimes with granulomas), and autoimmune hepatitis shows prominent portal and lobular lymphoplasmacytic inflammation. Both have a wide differential diagnosis, including one another; they may also simultaneously occur within the same patient. Careful use of clinical and histologic criteria may be necessary for diagnosis. First-line therapy is immunosuppression for autoimmune hepatitis and ursodeoxycholic acid for primary biliary cholangitis. Both diseases may progress to cirrhosis.

Geoepidemiology of Primary Biliary Cholangitis: Lessons from Switzerland

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

TRIAL REGISTRATION NUMBER

clinicaltrials.gov : NCT02846896; SNCTP000001870.

Work in Progress: Drugs in Development

Primary biliary cholangitis is an archetypal autoimmune disease that causes cholestasis, fibrosis, and liver failure. Ursodeoxycholic acid and obeticholic acid are approved for its treatment. Not all patients respond, some are intolerant, many have ongoing symptoms, and new therapies are required. Herein we describe drugs in development and potential future biological targets. We consider compounds acting on the farnesoid X receptor/fibroblast growth factor 19 pathway, fibrates and other agonists of the peroxisome proliferator-activated receptor family, transmembrane-G-protein-receptor-5 agonists, and several immunological agents. We also consider the roles of bile acid reuptake inhibitors, nalfurafine, and fibrates in pruritus management.

Factors Associated With Prevalence and Treatment of Primary Biliary Cholangitis in United States Health Systems

BACKGROUND & AIMS

Reported prevalence of primary biliary cholangitis (PBC) varies widely. Demographic features and treatment patterns are not well characterized in the United States (US). We analyzed data from the Fibrotic Liver Disease (FOLD) Consortium, drawn from 11 geographically diverse health systems, to investigate epidemiologic factors and treatment of PBC in the US.

METHODS

We developed a validated electronic health record-based classification model to identify patients with PBC in the FOLD database from 2003 through 2014. We used multivariable modeling to assess the effects of factors associated with PBC prevalence and treatment with ursodeoxycholic acid (UDCA).

RESULTS

We identified 4241 PBC cases among over 14.5 million patients in FOLD health systems; median follow-up was 5 years. Accuracy of the classification model was excellent, with an area under the receiver operating characteristic curve value of 93%, 94% sensitivity, and 87% specificity. The average patient age at diagnosis was 60 years; 21% were Hispanic, 8% were African American, and 7% were Asian American/American Indian/Pacific Islander. Half of the cohort (49%) had elevated levels of alkaline phosphatase, and overall, 70% were treated with UDCA. The estimated 12-year prevalence of PBC was 29.3 per 100,000 persons. Adjusted prevalence values were highest among women (42.8 per 100,000), White patients (29.6 per 100,000), and patients 60-70 years old (44.7 per 100,000). Prevalence was significantly lower among men and African Americans (10.7 and 19.7 per 100,000, respectively) than women and whites; men and African Americans were also less likely to receive UDCA treatment (odds ratios, 0.6 and 0.5, respectively; P < .05).

CONCLUSIONS

In an analysis of a large cohort of patients with PBC receiving routine clinical care, we observed significant differences in PBC prevalence and treatment by gender, race, and age.

Risk stratification and prognostic modelling in primary biliary cholangitis

Primary biliary cholangitis (PBC) is a slowly progressive chronic cholestatic liver disease that, in a subgroup of patients, may result in liver failure or death. The definition of specific risk profiles, i.e. risk stratification, is of critical importance for the identification of these subgroups and thereby the targeting of care. Over the last few years large multicentre cohort studies have improved our knowledge regarding factors associated with progressive disease. Stratification based on biochemical response to ursodoxycholic acid provides a readily available measure to identify groups that might benefit from additional therapies to further improve prognosis. In addition, serum total bilirubin and alkaline phosphatase are now considered the most robustly validated biomarkers of long-term outcome in PBC and are used as endpoints in clinical trials. The GLOBE score and UK-PBC risk score enable us to quantify the risk of future events for the individual patient, allowing more individualized risk prediction. In this review, we discuss both established prognostic factors and newly developed tools to estimate prognosis in PBC, highlighting their strengths, limitations and applicability in clinical practice.

Evolution of our understanding of PBC

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

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

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

Autoantibodies in Autoimmune Liver Disease-Clinical and Diagnostic Relevance

Testing for liver-related autoantibodies should be included in the workup of patients with hepatitis or cholestasis of unknown origin. Although most of these autoantibodies are not disease specific, their determination is a prerequisite to diagnose autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC), and they are components of the diagnostic scoring system in these diseases. In primary sclerosing cholangitis (PSC), on the other hand, autoantibodies are frequently present but play a minor role in establishing the diagnosis. In PSC, however, data on antibodies suggest a link between disease pathogenesis and the intestinal microbiota. This review will focus on practical aspects of antibody testing in the three major autoimmune liver diseases AIH, PBC, and PSC.

Colchicine-Induced Hepatotoxicity

Drug-induced injury (DILI) is a frequent cause of abnormal liver tests and a leading cause of liver failure in the United States. Colchicine has long been used as a systemic anti-inflammatory agent for treatment of gout by inhibiting mitotic activity and neutrophil function. We present the first case of colchicine-induced hepatoxicity, supported by histopathologic findings characteristic of colchicine-induced injury and resolution of liver enzyme abnormalities after its discontinuation. Colchicine-associated DILI has implications for the evaluation of patients with abnormal liver tests and gout, especially for patients with alcoholism and non-alcoholic fatty liver disease, in whom there is an increased incidence of gout.

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.

Clinical characteristics of antimitochondrial antibody-positive patients at a safety net health care system in Arizona

Background and aims

To assess whether aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (AP) levels can predict the diagnosis of primary biliary cholangitis (PBC) or any other diagnoses and whether PBC occurs either simultaneously or independently of other liver diseases among antimitochondrial antibody (AMA)-positive patients.

Methods

Demographic and clinical variables were assessed in 90 AMA-positive patients with and without liver biopsies. These patients were further categorised as having a diagnosis of PBC, overlap syndrome or ‘not established with a diagnosis of PBC’. Receiver operating characteristic curves were constructed to determine the thresholds of liver enzymes that predict these three diagnoses.

Results

The 48 patients with liver biopsies were more frequently female and had significantly higher AP levels compared with the non-liver biopsy group. Based on liver biopsy findings, 12, 12 and 22 patients were assigned a diagnosis of PBC, overlap syndrome with autoimmune hepatitis and PBC and ‘not established diagnosis of PBC’, respectively. Seven of 12 patients classified as PBC had AP level of ˂200 IU. AST, ALT and AP levels were significant predictors of a diagnosis of overlap syndrome compared with the rest of the patients; however, these tests were not discriminatory between diagnoses of PBC and ‘not established with PBC’. Findings of fatty liver and bile duct injury on liver biopsies were not significantly associated with any liver test pattern.

Conclusions

As the liver test pattern did not correlate with the liver biopsy findings of PBC or other non-PBC diagnoses in AMA-positive patients at risk for other disease, a liver biopsy and/or non-invasive liver assessment along with serum liver tests should be interpreted to complete liver evaluation.

EASL Clinical Practice Guidelines: The diagnosis and management of patients with primary biliary cholangitis

Primary biliary cholangitis (PBC) is a chronic inflammatory autoimmune cholestatic liver disease, which when untreated will culminate in end-stage biliary cirrhosis. Diagnosis is usually based on the presence of serum liver tests indicative of a cholestatic hepatitis in association with circulating antimitochondrial antibodies. Patient presentation and course can be diverse and risk stratification is important to ensure all patients receive a personalised approach to their care. The goals of treatment and management are the prevention of end-stage liver disease, and the amelioration of associated symptoms. Pharmacologic approaches in practice, to reduce the impact of the progressive nature of disease, currently include licensed therapies (ursodeoxycholic acid and obeticholic acid) and off-label therapies (fibric acid derivatives, budesonide). These clinical practice guidelines summarise the evidence for the importance of a structured, life-long and individualised, approach to the care of patients with PBC, providing a framework to help clinicians diagnose and effectively manage patients.

Inflammatory myopathy associated with anti-mitochondrial antibodies: A distinct phenotype with cardiac involvement

OBJECTIVE

In the context of clinical evaluations performed on our prospective myositis cohort, we noted a striking association of severe cardiac disease in myositis patients with anti-mitochondrial antibodies. We sought to review all cases of anti-mitochondrial antibody (AMA) associated myositis in our cohort to describe the clinical features of this disease subset.

METHODS

We identified 7 patients with confirmed anti-mitochondrial antibodies who presented as an inflammatory myopathy. A retrospective chart review was completed to assess their clinical presentation, laboratory, imaging, electrophysiologic, and histopathologic features.

RESULTS

One patient presented with dermatomyositis and 6 were classified as polymyositis using Bohan and Peter criteria. In all but one patient, a chronic course of muscle involvement was appreciated with an average of 6.5 years of weakness prior to presentation. Muscle atrophy was often noted, as well as atypical findings of scapular winging in 2 of the patients. Muscle biopsies were consistent with immune-mediated necrotizing myopathy in 4 patients, dermatomyositis in 1, polymyositis in 1 and nonspecific or granulomatous myositis in 1 patient. Changes pointing to mitochondrial alterations were seen in 2 of the 7 patients. Cardiac involvement (including myocarditis, atrial and ventricular arrhythmias, and cardiomyopathy), was seen in 5 out of 7 (71%) of the patients, and usually preceded the muscle involvement. Coexisting autoimmune conditions were seen in 3/7of the patients and included primary biliary cirrhosis, autoimmune hepatitis, psoriasis, and Hashimoto's thyroiditis.

CONCLUSIONS

Anti-mitochondrial antibodies identify a distinct inflammatory myopathy phenotype that is frequently associated with chronic skeletal muscle disease and severe cardiac involvement. Early recognition of this rare entity as an immune-mediated process is important due to implications for treatment. We propose that anti-mitochondrial antibody status should be determined in patients with a compatible clinical picture.