Characterization of antimitochondrial antibodies in health adults

Predicting and preventing autoimmunity: the case of anti-mitochondrial antibodies

To be able to predict who will develop autoimmune disease would allow for early treatment which may dramatically alter the course of the disease. In some cases, it may also lead to prevention of the disease development. The prediction of disease development is based on the analysis of risk factors which have been associated with the disease in question. These factors include genetic susceptibility, as well as immunological and environmental factors. One autoimmune disease that may serve as a model for disease prediction is primary biliary cirrhosis (PBC), an autoimmune liver disease affecting the small- and medium-sized bile ducts. PBC could be an ideal model due to recent advances in elucidating its genetic associations. As well, a variety of immunological and environmental risk factors have been well established. Indeed, the presence of PBC-specific antimitochondrial antibodies and/or antinuclear antibodies has been shown to be predictor of disease development and possibly prognosis. This review will examine the current evidence which suggests that we may potentially be able to predict the development of PBC in some individuals. These concepts may also be applied to autoimmune diseases in general.

Primary biliary cirrhosis-specific autoantibodies in first degree relatives of Greek primary biliary cirrhosis patients

AIM: To determine the prevalence and significance of primary biliary cirrhosis (PBC)-specific autoantibodies in first-degree relatives (FDRs) of Greek PBC patients.

METHODS: The presence of antimitochondrial antibodies (AMA) and PBC-specific antinuclear antibodies (ANA) were determined using indirect immunofluorescence assays, dot-blot assays, and molecularly based enzyme-linked immunosorbent assays in 101 asymptomatic for liver-related symptoms FDRs of 44 PBC patients. In order to specify our results, the same investigation was performed in 40 healthy controls and in a disease control group consisting of 40 asymptomatic for liver-related symptoms FDRs of patients with other autoimmune liver diseases namely, autoimmune hepatitis-1 or primary sclerosing cholangitis (AIH-1/PSC).

RESULTS: AMA positivity was observed in 19 (only 4 with abnormal liver function tests) FDRs of PBC patients and none of the healthy controls. The prevalence of AMA was significantly higher in FDRs of PBC patients than in AIH-1/PSC FDRs and healthy controls [18.8%, 95% confidence interval (CI): 12%-28.1% vs 2.5%, 95% CI: 0.1%-14.7%, P = 0.01; 18.8%, 95% CI: 12%-28.1% vs 0%, 95% CI: 0%-10.9%, P = 0.003, respectively]. PBC-specific ANA positivity was observed in only one FDR from a PSC patient. Multivariate analysis showed that having a proband with PBC independently associated with AMA positivity (odds ratio: 11.24, 95% CI: 1.27-25.34, P = 0.03) whereas among the investigated comorbidities and risk factors, a positive past history for urinary tract infections (UTI) was also independently associated with AMA detection in FDRs of PBC patients (odds ratio: 3.92, 95% CI: 1.25-12.35, P = 0.02).

CONCLUSION: In FDRs of Greek PBC patients, AMA prevalence is significantly increased and independently associated with past UTI. PBC-specific ANA were not detected in anyone of PBC FDRs.

Primary biliary cirrhosis and liver transplantation

Primary biliary cirrhosis (PBC) is an immune-mediated chronic progressive inflammatory liver disease, predominantly affecting middle-aged women, characterized by the presence of antimitochondrial antibodies (AMAs), which can lead to liver failure. Genetic contributions, environmental factors including chemical and infectious xenobiotics, autoimmunity and loss of tolerance have been aggressively investigated in the pathogenesis of PBC, however, the actual impact of these factors is still controversial. Survival of PBC patients has been largely improved with the widespread use of ursodeoxycholic acid (UDCA), however, one third of patients still do not respond to the treatment and proceed to liver cirrhosis, requiring liver transplantation as a last resort for cure. The outcome of liver transplantation is excellent with 5- and 10-year survival rates around 80% and 70%, respectively, while along with long survival, the recurrence of the disease has become an important outcome after liver transplantation. Prevalence rates of recurrent PBC rage widely between 1% and 35%, and seem to increase with longer follow-up. Center-specific issues, especially the use of protocol biopsy, affect the variety of incidence, yet, recurrence itself does not affect patient and graft survival at present, and retransplantation due to recurrent disease is extremely rare. With a longer follow-up, recurrent disease could have an impact on patient and graft survival.

Primary biliary cirrhosis

Primary biliary cirrhosis is a chronic liver disease characterised by intrahepatic bile-duct destruction, cholestasis, and, in some cases, cirrhosis. Evidence supporting the autoimmune nature of this disorder includes the appearance of highly specific antimitochondrial antibodies (AMAs) and autoreactive T cells. Concordance rates in monozygotic twins, familial prevalence, and genetic associations underscore the importance of genetic factors, whereas findings of epidemiological studies and murine models suggest a possible role for exogenous chemicals and infectious agents through molecular mimicry. The incidence of primary biliary cirrhosis has increased over recent decades, possibly attributable to augmented testing of liver biochemistry rather than a rise in disease incidence. AMAs remain the hallmark of diagnosis in most cases and allow detection of asymptomatic patients. Symptomatic individuals usually present with either pruritus or fatigue and, more rarely, with either jaundice or complications of cirrhosis. The prognosis of primary biliary cirrhosis has improved because of early diagnosis and use of ursodeoxycholic acid, the only established medical treatment for this disorder. Although not a cure, treatment can slow disease progression and delay the need for liver transplantation. However, some patients do not respond adequately to ursodeoxycholic acid and might need alternative therapeutic approaches.

Disease-specific autoantibodies in primary biliary cirrhosis

Anti-mitochondrial autoantibodies (AMA) are specific markers of primary biliary liver cirrhosis (PBC), a cholestatic autoimmune disease which is characterised by a progressive destruction of the biliary epithelial cells followed by fibrosis, cirrhosis and liver failure. The prevalence of AMA in PBC is more than 90% and they can precede long before the clinical symptoms. AMA are conventionally detected by indirect immunofluorescence (IIF) using rodent liver, kidney, and stomach sections as substrates. Additionally, different PBC-specific anti-nuclear autoantibodies (ANA) can be observed in 30% of patients presenting with multiple nuclear dot or nuclear membrane staining patterns, which preferentially are identified using HEp-2 cells as substrate. The identification of the major PBC-specific mitochondrial and nuclear targets has allowed the generation of monospecific antigenic targets which are increasingly used in solid-phase assays for routine detection of AMA and ANA in mono- or multiparametric screen test systems. In the present paper, we give an overview of the diagnostic significance of autoantibodies in PBC, discuss the competencies of different techniques used for their determination and propose an effective diagnostic strategy.

Risk factors and prediction of long-term outcome in primary biliary cirrhosis

The natural history of the disease varies greatly among individual patients with primary biliary cirrhosis (PBC). Some patients live long without any symptoms while other patients present jaundice and develop hepatic failure in early phases of the disease. Previous studies showed that the natural course of PBC is altered by the use of ursodeoxy cholic acid (UDCA). In this review we discuss variation in the natural course of the disease and it's alteration by UDCA, and risk factors that predict disease progression. Based on clinical observations, there are three types of clinical evolution in PBC: 1) minimal to slow progression over several years; 2) rapid progression to jaundice and hepatic failure, and 3) progression to portal hypertension without developing deep jaundice. Notably, based on our analyses accelerated progression to jaundice and liver failure are reflected by a sustained serologic presence of anti-gp210 antibodies whereas patients with portal hypertension in the absence of jaundice have anti-centromere autoantibodies. These observations highlight the clinical importance of antinuclear antibody analysis in patients with PBC.

Primary biliary cirrhosis and autoimmune hepatitis: apotopes and epitopes

Autoimmune liver diseases (ALDs) represent a wide spectrum of chronic inflammatory diseases that are characterized by an immune-mediated attack against either hepatocytes (in the case of autoimmune hepatitis types 1 and 2, AIH-1, 2) or cholangiocytes (in primary biliary cirrhosis, PBC). PBC is considered a model autoimmune disease due to the homogeneity of patients, the high specificity of antimitochondrial antibodies (AMAs), and the specificity of biliary epithelial cell (BEC) destruction. It ensues from a multi-lineage loss of tolerance to the E2 component of the pyruvate dehydrogenase complex (PDC-E2). One of the major unanswered questions in the pathogenesis of PBC is the specificity of small intrahepatic bile duct attack while PDC-E2 is present in mitochondria of nucleated cells. Recent findings suggest that the apoptosis of BECs may be of considerable importance for understanding PBC, and that they are more than simply an innocent victim of an immune attack. Rather, they attract immune attack by virtue of the unique biochemical mechanisms by which they handle PDC-E2. The role of apoptotic cells in AIH is not well defined, but advances in the study of autoreactive T cells stem mostly from AIH type 2, where the main autoantigen (CYP2D6) is known, enabling the characterization of antigen-specific immune responses. This review article is intended to provide a critical overview of current evidence on tissue specificity in ALDs, as well as the characteristics of the relevant epitopes and apotopes and their biological and clinical significance.

Biliary apotopes and anti-mitochondrial antibodies activate innate immune responses in primary biliary cirrhosis

Our understanding of primary biliary cirrhosis (PBC) has been significantly enhanced by the rigorous dissection of the multilineage T and B cell response against the immunodominant mitochondrial autoantigen, the E2 component of the pyruvate dehydrogenase complex (PDC-E2). PDC-E2 is a ubiquitous protein present in mitochondria of nucleated cells. However, the damage of PBC is confined to small biliary epithelial cells (BECs). We have previously demonstrated that BECs translocate immunologically intact PDC-E2 to apoptotic bodies and create an apotope. To define the significance of this observation, we have studied the ability of biliary or control epithelial apotopes to induce cytokine secretion from mature monocyte-derived macrophages (MDMphis) from either patients with PBC or controls in the presence or absence of anti-mitochondrial antibodies (AMAs). We demonstrate that there is intense inflammatory cytokine production in the presence of the unique triad of BEC apotopes, macrophages from patients with PBC, and AMAs. The cytokine secretion is inhibited by anti-CD16 and is not due to differences in apotope uptake. Moreover, MDMphis from PBC patients cultured with BEC apoptotic bodies in the presence of AMAs markedly increase tumor necrosis factor-related apoptosis-inducing ligand expression.

CONCLUSION

These results provide a mechanism for the biliary specificity of PBC, the recurrence of disease after liver transplantation, and the success of ursodiol in treatment. They further emphasize the critical role of the innate immune system in the perpetuation of this autoimmune disease.

The spectrum of autoantibodies in IPEX syndrome is broad and includes anti-mitochondrial autoantibodies

IPEX syndrome is a congenital disorder of immune regulation caused by mutations in the FOXP3 gene, which is required for the suppressive function of naturally arising CD4 + CD25 + regulatory T cells. In this case series we evaluated serum samples from 12 patients with IPEX syndrome for the presence of common autoantibodies associated with a broad range of autoimmune disorders. We note that 75% of patients (9/12) had 1 or more autoantibodies, an incidence far above the cumulative rate observed in the general population. The range of autoantibodies differed between patients and there was no predominant autoantibody or pattern of autoantibodies present in this cohort. Surprisingly, one patient had high-titer anti-mitochondrial antibodies (AMA) typically associated with primary biliary cirrhosis (PBC) although the patient had no signs of cholestasis. PBC is a well-characterized autoimmune disease that occurs primarily in women and includes the serological hallmarks of serum AMA and elevated IgM which were both present in this patient. PBC is virtually absent in children with the exception of one reported child with interleukin 2 receptor α (CD25) deficiency which is associated with an IPEX-like regulatory T cell dysfunction. Based on the present data and the available literature we suggest a direct role for CD4 + CD25 + regulatory T cells in restraining B cell autoantibody production and that defects in regulatory T cells may be crucial to the development of PBC.

Methotrexate for primary biliary cirrhosis

BACKGROUND

Methotrexate has been used to treat patients with primary biliary cirrhosis as it possesses immunosuppressive properties. The previously prepared version of this review from 2005 showed that methotrexate seemed to significantly increase mortality in patients with primary biliary cirrhosis. Since that last review version, follow-up data of the included trials have been published.

OBJECTIVES

To assess the beneficial and harmful effects of methotrexate for patients with primary biliary cirrhosis.

SEARCH STRATEGY

Randomised clinical trials were identified by searching The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, and EMBASE (from their inception until September 2009). Reference lists were also read through. Authors of trials were contacted.

SELECTION CRITERIA

We searched to include randomised clinical trials comparing methotrexate with placebo, no intervention, or another drug irrespective of blinding, language, year of publication, or publication status.

DATA COLLECTION AND ANALYSIS

Our primary outcomes were mortality, and mortality or liver transplantation combined. Dichotomous outcomes were reported as relative risks (RR) and hazard ratios (HR) if applicable. Continuous outcomes were reported as mean differences (MD).

MAIN RESULTS

Five trials were included. Four trials with 370 patients compared methotrexate with placebo or no intervention (three trials added an equal dose of ursodeoxycholic acid to the intervention groups). The bias risk of these trials was high. We did not find statistically significant effects of methotrexate on mortality (RR 1.32, 95% CI 0.66 to 2.64), mortality or liver transplantation combined, pruritus, fatigue, liver complications, liver biochemistry, liver histology, or adverse events. The pruritus score (MD - 0.17, 95% CI - 0.25 to - 0.09) was significantly lower in patients receiving methotrexate. The prothrombin time was significantly worsened in patients receiving methotrexate (MD 1.60 s, 95% CI 1.18 to 2.02). One trial with 85 patients compared methotrexate with colchicine. The trial had low risk of bias. Methotrexate, when compared to colchicine, did not significantly effect mortality, fatigue, liver biopsy, or adverse events. Methotrexate significantly benefited pruritus score (MD - 0.68, 95% CI - 1.11 to - 0.25), serum alkaline phosphatases (MD - 0.41 U/l, 95% CI - 0.70 to - 0.12), and plasma immunoglobulin M (MD - 0.47 mg/dl, 95% CI - 0.74 to - 0.20) compared with colchicine. Other outcomes showed no statistical difference.

AUTHORS' CONCLUSIONS

Methotrexate had no statistically significant effect on mortality in patients with primary biliary cirrhosis nor the need for liver transplantation. Although methotrexate may benefit other outcomes (pruritus score, serum alkaline phosphatase, immunoglobulin M levels), there is no sufficient evidence to support methotrexate for patients with primary biliary cirrhosis.

Primary biliary cirrhosis: a 2010 update

Primary biliary cirrhosis (PBC) is a chronic inflammatory autoimmune disease that mainly targets the cholangiocytes of the interlobular bile ducts in the liver. The condition primarily affects middle-aged women. Without treatment, PBC generally progresses to cirrhosis and eventually liver failure over a period of 10-20 years. PBC is a rare disease with prevalence of less than 1/2000. PBC is thought to result from a combination of multiple genetic factors and superimposed environmental triggers. The contribution of the genetic predisposition is evidenced by the familial clustering. Several risk factors, including exposure to infectious agents and chemical xenobiotics, have been suggested. Ursodeoxycholic acid (UDCA) is currently the only FDA-approved medical treatment for PBC. When administered at doses of 13-15 mg/kg/day, a majority of patients with PBC have a normal life expectancy without additional therapeutic measures. One out of three patients does not adequately respond to UDCA therapy and may need additional medical therapy and/or liver transplantation. This review summarises current knowledge on the epidemiology, ethiopathogenesis, clinical, and therapeutic aspects of PBC.

The unfinished business of primary biliary cirrhosis

In nearly every multifactorial human disease, there are three periods that characterize our understanding and definition. First, there is a period in which there is rapid accumulation of descriptive data. Second, there is a longer and slower period as information is obtained that redefines and expands basic and clinical knowledge that lacks the final and important area of understanding aetiology and therapeutic intervention. Third, which is much less common for most diseases, is the vigorous definition of pathobiology and treatment. These phases are well illustrated by our current understanding of primary biliary cirrhosis (PBC). The term PBC was first used nearly 60 years ago and for the first 40 or so years, the primary research efforts were directed at clinical definitions and pathology. Subsequently, with the advent of molecular biology, there began a rigorous dissection of the immune response and, in particular, a better understanding of anti-mitochondrial antibodies. These efforts have greatly helped in our understanding of not only the effector mechanisms of disease, but also the uniqueness of the primary target tissue, biliary epithelium. However, this research has still not led to successful translation for specific therapy.

Long-term follow-up of antimitochondrial antibody-positive autoimmune hepatitis

Antimitochondrial antibodies (AMAs) are the serological hallmark for primary biliary cirrhosis (PBC). When AMAs are detected in patients with chronic hepatitis, they negatively impact on the autoimmune hepatitis (AIH) scoring system. The purpose of this study was to determine if AMAs detected in the sera of patients with overt AIH have clinical or pathological significance. All patients with a clinicopathologic diagnosis of AIH from one center were reviewed. Only those meeting the criteria for probable or definite AIH according to the International Autoimmune Hepatitis Group were included. Patients found to be consistently AMA-positive via enzyme-linked immunosorbent assay (ELISA) for pyruvate dehydrogenase complex E2 subunit were reviewed in detail. Fifteen of 126 patients with typical features of AIH (pretreatment AIH score >10) had detectable AMAs in serum. None had any histologic features suggestive of PBC. None had detectable anti-liver-kidney-microsomal antibodies. Of these 15 patients, all have remained persistently AMA-positive via ELISA. All 15 patients have been followed long-term, and their clinical course remained typical for AIH. No bile duct damage typical of PBC was seen on initial or follow-up liver biopsies.

CONCLUSION

Patients with overt AIH who test positive for AMAs at initial presentation and are treated with corticosteroid therapy have shown no clinical or histologic evidence of PBC despite the continued detection of AMAs over a follow-up of up to 27 years.

New insights into autoimmune liver diseases

Autoinflammatory liver disease represents an important aspect of global hepatological practice. The three principal disease divisions recognized are autoimmune hepatitis, primary sclerosing cholangitis and primary biliary cirrhosis. Largely, but not exclusively, these diseases are considered to be autoimmune in origin. Increased recognition of outlier and overlap syndromes, changes in presentation and natural history, as well as the increased awareness of IgG4-associated sclerosing cholangitis, all highlight the limitations of the classic terminology. New insights continue to improve the care given to patients, and have arisen from carefully conducted clinical studies, therapeutic trials, as well as genetic and laboratory investigations. The challenges remain to treat patients before liver injury becomes permanent and to prevent the development of organ failure.

Natural history of primary biliary cirrhosis

The natural history of primary biliary cirrhosis (PBC) has improved significantly over the last two decades. Most patients are diagnosed with asymptomatic PBC (a-PBC). The prognosis of a-PBC is usually better than that of symptomatic PBC (s-PBC). Among a-PBC patients, some remain asymptomatic, whereas others progress to s-PBC. The prognosis of s-PBC is still poor and the main cause of death in PBC is liver failure. Other complications, such as esophageal varices and hepatocellular carcinoma, also affect the prognosis of PBC patients. Ursodeoxycholic acid treatment improves the prognosis of PBC patients in the early stage. There seems to be several types of PBC progression.

Natural history of primary biliary cirrhosis

Primary biliary cirrhosis is an insidious disease that progresses through the clinical phases: preclinical, asymptomatic, symptomatic, and liver insufficiency. The outlook of patients diagnosed with PBC has improved significantly over the past 2 decades because more patients are being diagnosed earlier in the disease process and being treated with UDCA. A need remains to better define and predict the course of symptomatic and asymptomatic patients on and off UDCA in order to better evaluate outcomes of clinical trials.

Primary biliary cirrhosis: the future

Primary biliary cirrhosis is a progressive cholestatic liver disease of presumed autoimmune etiology. Patterns of disease are changing with earlier recognition and better access to investigation and treatment. With the convergence of animal, genetic, and clinical studies over the coming years, it is hoped that a greater understanding in the pathophysiology of the disease will translate into improved clinical endpoints for patients.

Presentation and diagnosis of primary biliary cirrhosis in the 21st century

Primary biliary cirrhosis is a slowly progressive, cholestatic, and chronic liver disease in which the epithelium of the intrahepatic biliary tree is destroyed by a chronic inflammatory process. The origin of this disease, which mainly affects middle-aged women, is unknown but has characteristics favoring an autoimmune etiology. This article reviews the presentation and diagnosis of PBC in the 21st century.

The causes of primary biliary cirrhosis: Convenient and inconvenient truths

The most difficult issue in autoimmunity remains etiology. Although data exist on effector mechanisms in many autoimmune diseases, the underlying cause or causes are still generically ascribed to genetics and environmental influences. Primary biliary cirrhosis (PBC) is considered a model autoimmune disease because of its signature antimitochondrial autoantibody (AMA), the homogeneity of clinical characteristics, and the specificity of biliary epithelial cell (BEC) pathology. Twenty years ago, we reported the cloning and identification of the E2 component of pyruvate dehydrogenase (PDC-E2) as the immunodominant autoantigen of PBC, allowing for vigorous dissection of T and B lymphocyte responses against PDC-E2 and development of several valid experimental models. There has also been considerable study of the biology of BECs, which has included the unique properties of apoptosis in which there is exposure of PDC-E2 to the effector processes of the immune system. In this review, we present these data in the context of our proposal that the proximal cause of PBC is autoimmunity directed against well-identified mitochondrially located autoantigens in individuals with inherited deficits of immune tolerance. We present these data under the umbrella of convenient truths that support this thesis as well as some inconvenient truths that are not readily accommodated by current theory.

CONCLUSION

We emphasize that the potential initiator of PBC includes inter alia particular environmental xenobiotics; pathogenesis is aided and abetted by genetic weaknesses in mechanisms of immune regulation; and subsequent multilineage immunopathology impacts upon uniquely susceptible BECs to culminate clinically in the chronic autoimmune cholangiolitis of PBC.

Primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology characterized by injury of the intrahepatic bile ducts that may eventually lead to liver failure. Affected individuals are usually in their fifth to seventh decades of life at time of diagnosis, and 90% are women. Annual incidence is estimated between 0.7 and 49 cases per million-population and prevalence between 6.7 and 940 cases per million-population (depending on age and sex). The majority of patients are asymptomatic at diagnosis, however, some patients present with symptoms of fatigue and/or pruritus. Patients may even present with ascites, hepatic encephalopathy and/or esophageal variceal hemorrhage. PBC is associated with other autoimmune diseases such as Sjogren's syndrome, scleroderma, Raynaud's phenomenon and CREST syndrome and is regarded as an organ specific autoimmune disease. Genetic susceptibility as a predisposing factor for PBC has been suggested. Environmental factors may have potential causative role (infection, chemicals, smoking). Diagnosis is based on a combination of clinical features, abnormal liver biochemical pattern in a cholestatic picture persisting for more than six months and presence of detectable antimitochondrial antibodies (AMA) in serum. All AMA negative patients with cholestatic liver disease should be carefully evaluated with cholangiography and liver biopsy. Ursodeoxycholic acid (UDCA) is the only currently known medication that can slow the disease progression. Patients, particularly those who start UDCA treatment at early-stage disease and who respond in terms of improvement of the liver biochemistry, have a good prognosis. Liver transplantation is usually an option for patients with liver failure and the outcome is 70% survival at 7 years. Recently, animal models have been discovered that may provide a new insight into the pathogenesis of this disease and facilitate appreciation for novel treatment in PBC.

Antimitochondrial antibodies in acute liver failure: implications for primary biliary cirrhosis

In our previous work, including analysis of more than 10,000 sera from control patients and patients with a variety of liver diseases, we have demonstrated that with the use of recombinant autoantigens, antimitochondrial autoantibodies (AMAs) are only found in primary biliary cirrhosis (PBC) and that a positive AMA is virtually pathognomonic of either PBC or future development of PBC. Although the mechanisms leading to the generation of AMA are enigmatic, we have postulated that xenobiotic-induced and/or oxidative modification of mitochondrial autoantigens is a critical step leading to loss of tolerance. This thesis suggests that a severe liver oxidant injury would lead to AMA production. We analyzed 217 serum samples from 69 patients with acute liver failure (ALF) collected up to 24 months post-ALF, compared with controls, for titer and reactivity with the E2 subunits of pyruvate dehydrogenase, branched chain 2-oxo-acid dehydrogenase, and 2-oxo-glutarate dehydrogenase. AMAs were detected in 28/69 (40.6%) ALF patients with reactivity found against all of the major mitochondrial autoantigens. In addition, and as further controls, sera were analyzed for autoantibodies to gp210, Sp100, centromere, chromatin, soluble liver antigen, tissue transglutaminase, and deaminated gliadin peptides; the most frequently detected nonmitochondrial autoantibody was against tissue transglutaminase (57.1% of ALF patients).

CONCLUSION

The strikingly high frequency of AMAs in ALF supports the thesis that oxidative stress-induced liver damage may lead to AMA induction. The rapid disappearance of AMAs in these patients provides further support for the contention that PBC pathogenesis requires additional factors, including genetic susceptibility.

Increased prevalence of antimitochondrial antibodies in first-degree relatives of patients with primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disorder that can progress to cirrhosis, shortening life expectancy. PBC patients are often asymptomatic, present with biochemical cholestasis, and test positive (>or=90%) for antimitochondrial antibodies (AMAs) in serum. Although AMA positivity without biochemical cholestasis may indicate increased risk of future PBC development, the contribution of these antibodies to pathogenesis remains enigmatic. Environmental risks and genetic determinants are likely implicated in PBC etiology. Given the familial aggregation of PBC, we hypothesized that AMAs also aggregate among relatives of PBC probands. We investigated the prevalence of AMAs in first-degree relatives (FDRs) of PBC probands to examine whether AMAs aggregate in such pedigrees. Using a PBC family registry, we prospectively screened for AMAs in the serum of 306 FDRs in 145 pedigrees, 350 PBC probands, and 196 controls who were age-matched, sex-matched, race-matched, and residence-matched to probands. The prevalence of AMA in FDRs and controls was 13.1% and 1%, respectively. Greater prevalence of AMA was found in female FDRs of PBC probands [sisters (20.7%), mothers (15.1%), and daughters (9.8%)] than in male FDRs [brothers (7.8%), fathers (3.7%), and sons (0%)].

CONCLUSIONS

AMAs aggregate among FDRs of PBC probands. Our data have clinical implications for FDRs of PBC probands because AMA positivity may suggest susceptibility to PBC. Thus, the identification and follow-up of these relatives may lead to earlier disease diagnosis and treatment. Furthermore, if AMA development is heritable, this trait will provide a basis to dissect the genetic predisposition to PBC.

Cyclosporin A for primary biliary cirrhosis

BACKGROUND

Cyclosporin A has been used for patients with primary biliary cirrhosis, but the therapeutic responses in randomised clinical trials have been heterogeneous.

OBJECTIVES

To assess the beneficial and harmful effects of cyclosporin A for patients with primary biliary cirrhosis.

SEARCH STRATEGY

Relevant randomised clinical trials were identified by searching The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, The Chinese Biomedical Database, and LILACS, and manual searches of bibliographies to June 2006. We contacted authors of trials and the company producing cyclosporin A.

SELECTION CRITERIA

Randomised clinical trials comparing cyclosporin A with placebo, no intervention, or another drug were included irrespective of blinding, language, year of publication, and publication status.

DATA COLLECTION AND ANALYSIS

Our primary outcomes were mortality, and mortality or liver transplantation. Dichotomous outcomes were reported as relative risk (RR) and if appropriate, Peto odds ratio with 95% confidence interval (CI). Continuous outcomes were reported as weighted mean difference (WMD) or standardised mean difference (SMD). We examined intervention effects by random-effects and fixed-effect models.

MAIN RESULTS

We identified three trials with 390 patients that compared cyclosporin A versus placebo. Two of them were assessed methodologically adequate with low-bias risk. Cyclosporin A did not significantly reduce mortality risk (RR 0.92, 95% CI 0.59 to 1.45), and mortality or liver transplantation (RR 0.85, 95% CI 0.60 to 1.20). Cyclosporin A significantly improved pruritus (SMD -0.38, 95% CI -0.63 to -0.14), but not fatigue. Cyclosporin A significantly reduced alanine aminotransferase (WMD -41 U/L, 95% CI -63 to -18) and increased serum albumin level (WMD 1.66 g/L, 95% CI 0.26 to 3.05). Significantly more patients experienced adverse events in the cyclosporin A group than in the placebo group, especially renal dysfunction (Peto odds ratio 5.56, 95% CI 2.52 to 12.27) and hypertension (SMD 0.88, 95% CI 0.27 to 1.48).

AUTHORS' CONCLUSIONS

We found no evidence supporting or refuting that cyclosporin A may delay death, death or liver transplantation, or progression of primary biliary cirrhosis. Cyclosporin A caused more adverse events than placebo, like renal dysfunction and hypertension. We do not recommend the use of cyclosporin A outside randomised clinical trials.

Azathioprine for primary biliary cirrhosis

BACKGROUND

Azathioprine is used for patients with primary biliary cirrhosis, but the therapeutic responses in randomised clinical trials have been conflicting.

OBJECTIVES

To assess the benefits and harms of azathioprine for patients with primary biliary cirrhosis.

SEARCH STRATEGY

Randomised clinical trials were identified by searching The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, The Chinese Biomedical Database, and LILACS, and manual searches of bibliographies to September 2005.

SELECTION CRITERIA

Randomised clinical trials comparing azathioprine versus placebo, no intervention, or another drug were included irrespective of blinding, language, year of publication, and publication status.

DATA COLLECTION AND ANALYSIS

Our primary outcomes were mortality, and mortality or liver transplantation. Dichotomous outcomes were reported as relative risk (RR) with 95% confidence interval (CI). Continuous outcomes were reported as weighted mean difference (WMD) or standardised mean difference (SMD). We examined the intervention effects by random-effects and fixed-effect models.

MAIN RESULTS

We identified two randomised clinical trials with 293 patients. Only one of the trials was regarded as having low bias risk. Azathioprine did not significantly decrease mortality (RR 0.80, 95% CI 0.49 to 1.31, 2 trials). Azathioprine did not improve pruritus at one-year intervention (RR 0.71, 95% CI 0.28 to 1.84, 1 trial), cirrhosis development, or quality of life. Patients given azathioprine experienced significantly more adverse events than patients given no intervention or placebo (RR 2.44, 95% CI 1.14 to 5.20, 2 trials). The common adverse events were rash, severe diarrhoea, and bone marrow depression.

AUTHORS' CONCLUSIONS

There is no evidence to support the use of azathioprine for patients with primary biliary cirrhosis. Researchers who are interested in performing further randomised clinical trials should be aware of the risks of adverse events.

The X and why of xenobiotics in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic autoimmune liver disease characterized by inflammation and destruction of intrahepatic biliary epithelial cells, ultimately leading to liver failure. The serological hallmark of PBC is the presence of high-titer antimitochondrial antibodies (AMA) against the inner lipoyl domain of E2 subunits of 2-oxo-acid dehydrogenase complexes, in particular the E2 component of the pyruvate dehydrogenase complex (PDC-E2). The initiating events triggering the autoimmune response are not yet identified but the hypothesis of molecular mimicry is a widely proposed mechanism for the development of autoimmunity in PBC. Several candidates, including bacteria and viruses, have been suggested as causative agents, but also environmental factors, such as chemical xenobiotics, have been implicated in the pathogenesis of primary biliary cirrhosis. In this review, we will discuss our current knowledge of the immunoreactivity of xenobiotically modified PDC peptide antigens. In addition, we will provide a working hypothesis how xenobiotic modification of antigens might occur that ultimately leads to the breaking of self-tolerance and the induction of PBC.

A sensitive bead assay for antimitochondrial antibodies: Chipping away at AMA-negative primary biliary cirrhosis

The antimitochondrial response in primary biliary cirrhosis (PBC) is the most highly directed and specific self-reacting antibody in human immunopathology. Originally, antimitochondrial antibodies (AMAs) were detected by indirect immunofluorescence (IIF) and found in approximately 90% of well-documented patients with PBC. The introduction of recombinant autoantigens and the use of immunoblotting have increased the sensitivity and specificity of AMAs, and they are now considered positive in approximately 95% of patients with PBC. Clearly, accurate autoantibody detection represents one of the fundamental requirements for reliable diagnostics in autoimmunity. To address the 5% of AMA-negative patients with PBC, we have generated and validated a bead assay for the detection of AMA. We enrolled 120 patients with PBC, including a non-random group of 30 rigorously proven AMA-negative patients, 50 healthy subjects, and 74 controls with autoimmune diseases (18 with primary sclerosing cholangitis, 16 with autoimmune hepatitis, and 40 with systemic lupus erythematosus). Individual bead assays were done with the three mitochondrial autoantigens, PDC-E2, BCOADC-E2, and OGDC-E2. As expected, 90 of 90 previously known AMA-positive patients remained positive with this assay but, interestingly, 20% of the rigorously defined AMA-negative patient group had antibodies to one or more of the mitochondrial autoantigens. Furthermore, 100% of these newly detected AMA-positive patients were anti-nuclear antibody (ANA) positive.

CONCLUSION

The development of this assay reflects the potential for automated detection with rapid and reliable assaying and further highlights the diminished number of truly AMA-negative PBC patients.

AMA production in primary biliary cirrhosis is promoted by the TLR9 ligand CpG and suppressed by potassium channel blockers

We previously reported that peripheral blood mononuclear cells (PBMCs) from patients with primary biliary cirrhosis (PBC) produce significantly higher levels of polyclonal IgM than controls after exposure to CpG. Furthermore, the prevalence and unusually high levels of antimitochondrial antibodies (AMAs) in patients with PBC suggest a profound loss ofB cell tolerance. We have addressed the issue of whether CpG will promote the production ofAMAs and whether new experimental agents that inhibit the lymphocyte potassium channels Kv1.3 and KCa3.1 can suppress CpG-mediated B cell activation and AMA production. PBMCs were stimulated with and without CpG and were subsequently analyzed for phenotype, including expression of TLR9, CD86, and KCa3.1 concurrent with measurements of AMA and responses to a control antigen, tetanus toxoid, in supernatants. Additionally, K+ channel expression on B cells from PBC patients and controls was studied using whole-cell patch-clamp technology. In patients with PBC, CpG induces secretion of AMAs in PBMCs andalso up-regulates B cell expression of TLR9, CD86, and KCa3.1. Additionally, K+ channel blockers suppress secretion of AMA without a reduction of CpG-B-enhanced IgM production. Furthermore, there is diminished up-regulation of TLR9 and CD86 without affecting proliferation of B cells, B cell apoptosis, or viability.

CONCLUSION

These data suggest that the hyperresponsiveness of B cells in PBC accelerates B cell-mediated autoimmunity.

The presence of anti-mitochondrial antibodies in Chinese patients with liver involvement in systemic lupus erythematosus

Sixty-six hospitalized patients with systemic lupus erythematosus (SLE) were enrolled into this study. The test for anti-mitochondrial antibodies (AMAs) was performed and biochemical parameters were determined. AMAs were detected in 15 of the 66 patients with SLE. Meanwhile, we compared enzymatic levels in AMA-positive and -negative patients and found that serum aminotransferase levels were significantly higher in AMA-positive patients than in AMA-negative individuals. Furthermore, we found a positive correlation between serum AMA titration and serum aminotransferase levels. This study suggests that AMAs might contribute to the elevation of aminotransferases. Although much remains to be learned about the pathogenesis of autoimmune liver disease associated with AMAs, this report might provide greater insight into the metabolic mechanisms of AMAs in AMA-positive patients.

Increased serum aminotransferases associated with anti-mitochondrial antibodies in systemic lupus erythematosus patients with autoimmune liver disease

BACKGROUND

Serum aminotransferase activities are increased in many liver diseases, but the causes for the elevation might be difficult to determine. Whether the elevation of aminotransferases correlates with anti-mitochondrial antibodies (AMA) in systemic lupus erythematosus (SLE) patients with autoimmune liver disease deserves further consideration.

METHODS

A meticulous review was done in a large SLE cohort searching for laboratory features of the presence of AMA. Forty-eight hospitalized SLE patients with AMA and 60 randomly selected SLE patients without AMA as a matched case control were enrolled into the retrospective study. Laboratory data were collected, analyzed and compared in SLE patients with and without AMA.

RESULTS

Serum activities of aminotransferases were significantly increased in the 48 SLE patients with AMA compared with the 60 subjects without AMA. Meanwhile, we found a positive correlation between serum AMA titers and serum aminotransferase activities.

CONCLUSION

Although much remains to be learned about the pathogenesis of autoimmune liver disease associated with AMA, it is possible to suggest that AMA might contribute to the elevation of aminotransferases in SLE patients with the progressive disease.

Colchicine for primary biliary cirrhosis: a Cochrane Hepato-Biliary Group systematic review of randomized clinical trials

OBJECTIVES

Colchicine is used for patients with primary biliary cirrhosis due to its immunomodulatory and antifibrotic potential. The results from randomized clinical trials have, however, been inconsistent. We conducted a systematical review to evaluate the effect of colchicine for primary biliary cirrhosis.

METHODS

We identified randomized clinical trials comparing colchicine with placebo/no intervention. We analyzed effects by fixed and random effects model. We investigated heterogeneity by subgroup and sensitivity analyses.

RESULTS

We included 10 trials involving 631 patients, four of which were high-quality trials. No significant differences were detected between colchicine and placebo/no intervention regarding mortality (relative risk (RR), 1.21; 95% confidence interval (CI), 0.71-2.06), mortality or liver transplantation (RR = 1.00; 95% CI, 0.67-1.49), liver complications, liver biochemical variables, liver histology, or adverse events. Regarding mortality, an extreme case analysis favoring colchicine did not demonstrate beneficial effects of colchicine, whereas an extreme case analysis favoring placebo/no intervention demonstrated a detrimental effect of colchicine (RR = 2.28; 95% CI, 1.17-4.44). The number of patients without improvement of pruritus significantly decreased in the colchicine group (RR = 0.75; 95% CI, 0.65-0.87). However, this estimate was based on only 156 patients from three trials.

CONCLUSIONS

There is insufficient evidence to support the use of colchicine for patients with primary biliary cirrhosis. As we are unable to exclude a risk of increased mortality, we recommend to use colchicine only in randomized clinical trials.

Methotrexate for primary biliary cirrhosis

BACKGROUND

Methotrexate, a folic acid antagonist with immunosuppressive properties, has been used to treat patients with primary biliary cirrhosis. The therapeutic responses to methotrexate in randomised clinical trials have been heterogeneous.

OBJECTIVES

To assess the beneficial and harmful effects of methotrexate for patients with primary biliary cirrhosis.

SEARCH STRATEGY

Relevant randomised clinical trials were identified by searching The Cochrane Hepato-Biliary Group Controlled Trials Register (June 2004), The Cochrane Central Register of Controlled Trials on The Cochrane Library (Issue 2, 2004), MEDLINE (January 1966 to August 2004), EMBASE (January 1980 to August 2004), and manual searches of bibliographies. We contacted authors of trials and pharmaceutical companies.

SELECTION CRITERIA

Randomised clinical trials comparing methotrexate with placebo, no intervention, or another drug were included irrespective of blinding, language, year of publication, and publication status.

DATA COLLECTION AND ANALYSIS

Our primary outcomes were mortality and mortality or liver transplantation. Dichotomous outcomes were reported as relative risk (RR) and hazard ratio (HR) if applicable. Continuous outcomes were reported as weighted mean difference (WMD). We examined intervention effects by using both a random-effects model and a fixed-effect model. Heterogeneity was investigated by subgroup analyses and sensitivity analyses.

MAIN RESULTS

We identified four trials (370 patients) that compared methotrexate with placebo with or without ursodeoxycholic acid as co-intervention. One additional trial (87 patients) compared methotrexate with colchicine without and later with ursodeoxycholic acid as co-intervention. The methodological quality of the trials was low. We did not find significant effects of methotrexate on pruritus, fatigue, liver complications, liver biochemistry, liver histology, or adverse events. The pruritus score (WMD - 0.68, 95% CI - 1.11 to - 0.25), the levels of serum alkaline phosphatases (WMD - 0.41, 95% CI - 0.70 to - 0.12) and plasma immunoglobulin M (WMD - 0.47, 95% CI - 0.74 to - 0.20) were significantly lower in the patients receiving methotrexate.

AUTHORS' CONCLUSIONS

Methotrexate increased mortality in patients with primary biliary cirrhosis. We do not recommend methotrexate for patients with primary biliary cirrhosis outside randomised trials.

D-penicillamine for primary biliary cirrhosis

BACKGROUND

D-penicillamine is used for patients with primary biliary cirrhosis due to its hepatic copper decreasing and immunomodulatory potentials. The results from randomised clinical trials have been inconsistent.

OBJECTIVES

To systematically review the beneficial and harmful effects of D-penicillamine for patients with primary biliary cirrhosis.

SEARCH STRATEGY

We identified trials through electronic searches of The Cochrane Hepato-Biliary Group Controlled Trials Register (September 2003), The Cochrane Central Register of Controlled Trials on The Cochrane Library (Issue 3, 2003), MEDLINE (January 1966 to September 2003), EMBASE (January 1980 to September 2003), The Chinese Biomedical CD Database (January 1979 to August 2003), and LILACS (1982 to 2003); through manual searches of bibliographies; and by contacting authors of the trials and pharmaceutical companies.

SELECTION CRITERIA

We included randomised clinical trials comparing D-penicillamine with placebo/no intervention or other control intervention irrespective of language, year of publication, and publication status.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the methodological quality of the trials and extracted data, validated by a third reviewer. The primary outcomes were 1) mortality and 2) a combination of those who died or underwent liver transplantation. We analysed dichotomous outcomes as relative risk (RR) with 95% confidence interval (CI) by a fixed effect model and a random effects model. We investigated sources of heterogeneity by subgroup analyses and tested the robustness of our findings by sensitivity analyses.

MAIN RESULTS

We included seven trials randomising 706 patients with primary biliary cirrhosis. D-penicillamine compared with placebo/no intervention tended to increase mortality (RR 1.34, 95% CI 1.09 to 1.64, fixed; RR 1.46, 95% CI 0.85 to 2.50, random). However, there was substantial heterogeneity. No significant differences were detected regarding the risks of mortality or liver transplantation, pruritus, liver complications, progression of liver histological stage, or the levels of liver biochemical variables (except alanine aminotransferase). D-penicillamine versus placebo/no intervention significantly increased the risk of adverse events (RR 3.11, 95% CI 2.33 to 4.16, fixed; RR 4.18, 95% CI 1.38 to 12.69, random).

REVIEWERS' CONCLUSIONS

D-penicillamine did not appear to reduce the risk of mortality, but significantly increased the occurrences of adverse events in patients with primary biliary cirrhosis. We do not support the use of D-penicillamine for patients with primary biliary cirrhosis.

Prevalence of immune disturbances and chronic liver disease in family members of patients with primary biliary cirrhosis

BACKGROUND AND AIMS

Primary biliary cirrhosis (PBC) has been reported in up to 4-6% of first degree relatives of patients with the disease. In addition, immune abnormalities, including hypergammaglobulinemia, autoantibodies and increased frequency of autoimmune disorders, were reported in family members of PBC patients. The aim of the present study was to investigate the prevalence of PBC in relatives of patients with PBC, and to investigate the occurrence of chronic liver disease (CLD) and immune abnormalities in these subjects.

METHODS

One-hundred first degree relatives of 26 patients with PBC were interviewed and submitted to physical examination and determination of liver enzymes, gamma-globulin, bilirubin and auto-antibodies, including antinuclear (ANA), antismooth muscle (SMA), antimitochondrial antibodies (AMA) by indirect immunofluorescence (IIF) and anti-M2 antibody by immunoblotting (IB).

RESULTS

Immune disturbances were rarely observed in relatives of PBC patients. Higher gamma-globulin levels, SMA and ANA were detected in four, eight and two family members, respectively. In most subjects, these autoantibodies were either in low titers or associated with concurrent diseases. Only four relatives had extrahepatic autoimmune diseases and another eight exhibited other CLD. Primary biliary cirrhosis was detected in a sister of one patient. Additionally, two other relatives of PBC patients who tested negative for AMA by IIF showed reactivity for anti-M2 by IB.

CONCLUSIONS

Immune disturbances, including ANA and SMA, are uncommon in family members of PBC patients. Conversely, anti-M2 antibodies and overt PBC do occur in relatives of PBC patients, even in Brazil where the disease is quite rare.

Colchicine for primary biliary cirrhosis

BACKGROUND

Colchicine has been used for patients with primary biliary cirrhosis because of its immunomodulatory and antifibrotic potential. The therapeutical responses to colchicine in randomised clinical trials were inconsistent.

OBJECTIVES

To evaluate the beneficial and harmful effects of colchicine in patients with primary biliary cirrhosis.

SEARCH STRATEGY

We identified trials through electronic searches of The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials on The Cochrane Library, MEDLINE, EMBASE (September 2003), and manual searches of bibliographies. We contacted authors of trials and pharmaceutical companies.

SELECTION CRITERIA

Randomised clinical trials comparing colchicine with any kind of control therapy were included irrespective of language, year of publication, and publication status.

DATA COLLECTION AND ANALYSIS

The primary outcomes were the number of deaths and the number of death and/or patients who underwent liver transplantation. Dichotomous outcomes were reported as relative risk (RR) with 95% confidence interval (CI). We examined intervention effects by using both a fixed effect model and a random effects model. Heterogeneity was investigated by subgroup analyses and sensitivity analyses.

MAIN RESULTS

Eleven randomised clinical trials involving 716 patients with primary biliary cirrhosis fulfilled the inclusion criteria. No significant differences were detected between colchicine and placebo/no intervention on the number of deaths (RR 1.21, 95% CI 0.71 to 2.06), the number of deaths and/or patients who underwent liver transplantation (RR 1.00, 95% CI 0.67 to 1.49), liver complications, liver biochemical variables, liver histological measurements, and adverse events. Trial methodology was generally low and some trials had high drop-out rate. A best-worst-case-scenario analysis showed no significant effect of colchicine on mortality (RR 0.59, 95%CI 0.30 to 1.15), while a worst-best-case-scenario analysis showed a significant detrimental effect of colchicine on mortality (RR 2.28, 95% CI 1.17 to 4.44). Colchicine significantly decreased the number of patients without improvement of pruritus (RR 0.75, 95% CI 0.65 to 0.87). However, this estimate was based on only 156 patients from three trials. The effect of the combined treatment with ursodeoxycholic acid was not significantly different from that of colchicine alone.

REVIEWERS' CONCLUSIONS

We did not find evidence either to support or refute the use of colchicine for patients with primary biliary cirrhosis. As we are not able to exclude a detrimental effect of colchicine, we suggest that it is only used in randomised clinical trials.

The epidemiology of primary biliary cirrhosis

Over the last 30 years, many studies have reported on the epidemiology of PBC. Substantial increases in prevalence were noted in the majority of studies examining longitudinal data, and several have reported increases in the incidence of PBC. Furthermore, although it is difficult to compare studies directly, as methods of case ascertainment have greatly improved over this period, there has been a definite trend toward increasing prevalence (and also possibly incidence) across studies. Together, these data strongly suggest that in many countries, the frequency with which PBC is diagnosed has increased considerably between 1980 and the present time. The reasons for this change may be complex. There may have been a true increase in the incidence of PBC, reflecting either increased exposure to a currently unknown environmental etiological agent or demographic changes with an increased elderly, at-risk population. The prevalence may have further increased due to increased survival of patients, either due to improved care or earlier diagnosis. Some of the apparent increase in PBC frequency may also be artifactual, however, resulting from increased use of diagnostic tests, particularly autoantibody screens. This may be due to increased availability of testing, increased clinician (or patient) awareness of PBC, increased use of testing in well-person screening, or increased investigation of ill-defined symptoms. Furthermore, there may also have been an improvement in clinicians' ability to recognize PBC on the basis of the clinical picture (in one study, 37% of patients whose clinical results indicated a diagnosis of PBC were not recognized by the clinician caring for the patient at that time). The last factor alone suggests that all studies based only upon cases known to interested clinicians have probably substantially underestimated the prevalence of disease. Whatever the reason, the recognized epidemiology of PBC has dramatically changed over the past 30 years. It is now a frequent cause of liver morbidity, and patients with PBC are significant users of health resources, including liver transplantation. Large geographical variations in disease frequency, both between and within studies, tantalizingly suggest the presence of as-yet-unidentified risk factors. This should be further followed up with new analytical epidemiological studies. Only two case control studies have examined risk factors for PBC, and these have been either relatively small or used poorly defined and potentially biased experimental groups. These need repeating in new settings. We suggest that, as with other diseases, modern epidemiological instruments used in well-designed studies may provide important clues to the cause or causes of this disease.

Local antigen-driven oligoclonal expansion of B cells in the liver portal areas of patients with primary biliary cirrhosis

BACKGROUND/AIMS

The antigen-driven clonal proliferation of B cells within target tissue has been reported in some autoimmune diseases. The purpose of this study was to examine the clonal characteristics of B cells in the liver portal area of primary biliary cirrhosis (PBC).

METHODS

The liver portal area was microdissected from liver biopsy sections from two PBC patients. Genomic DNA was extracted and rearranged immunoglobulin heavy chain variable region (VH) genes were amplified and sequence analyzed.

RESULTS

Sixteen VH sequences from portal area 1A of patient 1 had three different rearrangements. Nineteen VH sequences from portal area 1B of this patient had three different rearrangements. In three sequences from the portal area 1B, a stepwise accumulation of somatic mutations was observed. Between the sequences from the two portal areas, no common VH sequence was observed. In patient 2, 15 VH sequences from portal area 2A had three different rearrangements. Fourteen VH sequences from portal area 2B had two different rearrangements. One rearrangement was present both in the portal area 2A and portal area 2B.

CONCLUSION

The oligoclonal B cell proliferation and stepwise accumulation of somatic mutations suggested that an antigen-driven B cell response had occurred in the portal area of PBC.

Epidemiology of autoimmune liver disease

Primary biliary cirrhosis (PBC), autoimmune hepatitis (AIH) and primary sclerosing cholangitis (PSC) are chronic liver diseases that likely have an autoimmune basis to their pathogenesis. Although significant strides have been made in the clinical management of these conditions, their pathogenesis remains obscure. Understanding of various epidemiological factors may shed light on predisposing or causative factors for these diseases. Most is known about the epidemiology of PBC, with only minimal information on that of PSC and AIH. In this review, the current data on the epidemiology of PBC, AIH and PSC are summarized and suggestions are made for future work in this important area.

Primary biliary cirrhosis among atomic bomb survivors in Nagasaki, Japan

Despite rapid progress in methods for analyzing radiation effects, much remains to be learned about the mechanisms and processes of radiation-induced immunological dysfunction. Among 17,899 sera obtained from atomic bomb survivors in Nagasaki, Japan, sera from 484 participants who complied with a reexamination for alkaline phosphatase (ALP) were tested for antimitochondrial antibody (AMA) by indirect immunofluorescence, and autoantibodies against 2-oxo-acid dehydrogenase complex (2-OADC) by immunoblotting to investigate the prevalence of primary biliary cirrhosis (PBC). Of these 484 sera, 28 (5.8%) were seropositive for AMA. The 484 participants were divided into three groups according to distance from the hypocenter: 72 who were exposed within 1999 m (closest group), 368 from 2000 to 5999 m (intermediate distant group), and 44 outside 6000 m (distant group). The positivity rates for AMA in these three groups were 6/72 (8.3%), 22/368 (6.0%), and 0/44 (0%), respectively (P =.08). Furthermore, high titers ( > 1:320) of AMA were observed in 3/6 (50%) AMA-positive sera from the closest group, in contrast to 4/22 (18%) from the intermediate distant group, although there was no significant correlation between AMA titer and distance from the hypocenter (P =.07). Of these 28 AMA-positive sera, 11 (39%) were from participants who had already been diagnosed with PBC, and 25 (89%) contained antibodies against at least one component of 2-OADC enzymes by immunoblotting. Therefore, the prevalence of PBC was estimated to be at least 615 cases per million (792 per million women). Our results suggest that the prevalence of PBC in atomic bomb survivors in Nagasaki is higher than that reported for the general population in Japan, and a further survey of the environmental factors, including radiation exposure, that predispose to PBC would be needed for understanding this disease of unknown etiology.

Anti-endothelial cell antibodies (AECA) in systemic sclerosis--increased sensitivity using different endothelial cell substrates and association with other autoantibodies

OBJECTIVE

One of the main features of systemic sclerosis (SSc) is vascular damage, the mechanism of which is not understood. In the present study we examined whether screening of SSc patients for different anti-endothelial cells antibodies (AECA) of various origins increase the sensitivity of AECA detection in SSc patients. Secondary aim was an attempt to correlate AECA with other common autoantibodies.

MATERIALS & METHODS

478 SSc patients were studied for the presence AECA, anti-cardiolipin (aCL), anti-dsDNA, anti-heparin (AHA), anti-pyruvate dehydrogenase (PDH) and anti-PDC-E2 autoantibodies. AECA levels were detemined using human umbilical vein EC (HUVEC), bone marrow EC (BMEC), EC hybridoma (EA.hy 926) and Kaposi sarcoma EC (KS).

RESULTS

Positive AECA were found in 49.5% of SSc patients (27.1% HUVEC; 34.3% BMEC; 26.3% EaHy 926 and 22.7% KS). The highest percent reactivity of AECA was obtained using microvascular BMEC. When combining BMEC and either other cell lines the reactivity ranged from 41.4% to 46%. A significant association between AECA on the one hand and AHA (p<0.001)) and anti-PDH (p<0.05) on the other was secn. Cross-reactivity with anti-PDC-E2 was excluded by inhibition tests, but AHA and anti-PDH may be part of the spectrum of AECA.

CONCLUSIONS

Since false-negative AECA may result from lack of expression of various antigens on a specific EC, analysis of AECA in SSc patients requires using several EC types, including microvascular EC.

Primary biliary cirrhosis: new perspectives in diagnosis and treatment

Primary biliary cirrhosis (PBC) is a chronic autoimmune disease characterised by cholestatic liver function tests, antimitochondrial antibodies, and abnormal liver histology. Early descriptions of a rare rapidly progressive disease no longer reflect the more indolent progress often seen today. Many patients have significant long term morbidity through symptoms such as fatigue and itch with a minority progressing to liver failure and need for transplantation. The current data on the diagnosis, clinical progression, and treatment of PBC are reviewed.

Is there a serological difference between men and women with primary biliary cirrhosis?

OBJECTIVE

Primary biliary cirrhosis (PBC) is an autoimmune disease affecting small intrahepatic bile ducts of the liver, causing destruction of the epithelium that results in eventual fibrosis and scarring. We still lack a complete epidemiological description of this disease, although interesting geographic differences in prevalence have been described. One consistent feature has been the relative scarcity of men with PBC. In fact, published ratios of women to men range from 3:1 to as high as 22:1. Thus far, the only clinical difference reported between men and women with PBC is a putative higher risk of hepatocarcinoma in men. Previous serological studies have shown that about 95% of all patients possess antimitochondrial antibodies to members of the highly conserved 2-oxo-acid dehydrogenase family of proteins, namely pyruvate dehydrogenase complex E2 (PDC-E2), branched-chain 2-oxo-acid dehydrogenase complex E2 (BCOADC-E2), and 2-oxo glutarate dehydrogenase complex E2 (OGDC-E2). However, there has been no information as to whether there is a difference in serological response between men and women. Using the serological hallmark of antimitochondrial antibodies (AMAs) and taking advantage of the availability of recombinant mitochondrial autoantigens, investigations were performed to determine if there were any serological differences between men and women with PBC.

METHODS

Sera were collected from 88 patients with PBC, of whom 46 were men and 42 were women. Using a combination of immunoblotting and enzyme-linked immunoabsorbent assay (ELISA) against beef heart mitochondria (BHM), recombinant PDC-E2, BCOADC-E2, and OGDC-E2, we determined the relative autoantibody reactivities of our study population.

RESULTS

Both men and women with PBC produced high titer antimitochondrial antibodies. The frequency of reactivity was similar in both groups and included, in descending order, PDC-E2, E3BP (Protein X), BCOADC-E2, and finally OGDC-E2. More importantly, antigenic specificity was nearly identical regardless of gender.

CONCLUSIONS

AMAs are the serological hallmark of PBC in both men and women, and there is no significant difference in reactivity between the two groups of patients.