The antinuclear autoantibodies Sp100 and gp210 persist after orthotopic liver transplantation in patients with primary biliary cirrhosis

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Anti-gp210-positive primary biliary cholangitis: The dilemma of clinical treatment and emerging mechanisms

Anti-gp210 is the disease-specific anti-nuclear antibody (ANA) of primary biliary cholangitis (PBC). Anti-gp210-positive PBC patients have worse responses to ursodeoxycholic acid (UDCA) as compared with anti-gp210-negative patients. Moreover, anti-gp210-positive patients always present with more severe histopathologic features including lobular inflammation, interfacial hepatitis, and bile duct injury, and have a worse prognosis than their anti-gp210-negative counterparts. Previous studies have identified two antigenic epitopes recognized by anti-gp210. Although the pathogenetic mechanism of anti-gp210 production remains unclear, evidence suggests that the autoimmune response to anti-gp210 production might be due to molecular mimicry induced by bacteria or endogenous peptides. T cells and related cytokines play a critical role in the pathogenesis of PBC, however, the mechanism hasn't been fully understood. Thus, this review focuses on the clinicopathological characteristics of anti-gp210-positive PBC patients, the fundamental research of gp210 antigen, and the possible mechanism of anti-gp210 production to clarify the mechanism of anti-gp210-positive PBC and provide potential molecular targets for disease prevention and treatment in the future.

Role of autoantibodies in the clinical management of primary biliary cholangitis

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease characterized by immune-driven destruction of small intrahepatic bile ducts leading a proportion of patients to hepatic failure over the years. Diagnosis at early stages in concert with ursodeoxycholic acid treatment has been linked with prevention of disease progression in the majority of cases. Diagnosis of PBC in a patient with cholestasis relies on the detection of disease-specific autoantibodies, including anti-mitochondrial antibodies, and disease-specific anti-nuclear antibodies targeting sp100 and gp210. These autoantibodies assist the diagnosis of the disease, and are amongst few autoantibodies the presence of which is included in the diagnostic criteria of the disease. They have also become important tools evaluating disease prognosis. Herein, we summarize existing data on detection of PBC-related autoantibodies and their clinical significance. Moreover, we provide insight on novel autoantibodies and their possible prognostic role in PBC patients.

Identification of Marker Genes and Pathways in Patients with Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterized by cholestasis and cirrhosis, and in which hepatic failure may occur. This study explores the changes in the gene expression profiles of liver tissues during the pathogenesis of PBC. Array dataset GSE79850 was downloaded from the Gene Expression Omnibus database. GeneSpring software was used to analyze differentially expressed genes (DEGs) in liver tissues from PBC patients compared with those from controls. Gene ontology (GO) annotation, the Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway enrichment analyses were performed by using Database for Annotation, Visualization and Integrated Discovery (DAVID) software. Cytoscape software was used to construct a protein-protein interaction (PPI) network. Plug-ins Molecular Complex Detection and iRegulon were used for clustering analysis and transcription factors related to key genes with PBC. A total of 77 DEGs, including 47 up- and 30 downregulated genes, were identified. The PPI network was established with 74 nodes and 356 protein pairs. The C-C motif chemokine ligand 5 (CCL5), interleukin 7 receptor (IL7R), and TNF receptor superfamily member 1A (TNFRSF1A) were identified as hub genes in the PPI network and may, therefore, be marker genes for PBC. Further, the upregulated genes CCL5 and IL7R, and downregulated TNFRSF1A were included in immune system processes as a GO term in the category Biological Processes. In conclusion, CCL5, IL7R, TNFRSF1A, and the immune response pathway may have crucial roles in PBC. These genes and pathways may be potential targets for treating PBC.

Diagnostic value of anti-gp210 antibodies in primary biliary cirrhosis: a case-based review

Primary biliary cirrhosis (PBC) is an autoimmune liver disease characterised by chronic cholestasis usually associated with antimitochondrial antibodies. Moreover, several types of antinuclear antibodies have been associated with primary biliary cirrhosis. We describe an 83-year-old man, in whom the exploration of a chronic cholestasis led to the diagnosis of primary biliary cirrhosis despite negative antimitochondrial antibodies, regarding the presence of anti-gp210 antibodies. Found in 25% of patients, these antinuclear antibodies must be sought before a strong suspicion of primary biliary cirrhosis with antimitochondrial antibodies negative, as they are highly specific of the disease. They are generally associated with a more aggressive form of PBC.

Molecular diagnostics of primary biliary cirrhosis

BACKGROUND

Primary biliary cirrhosis (PBC) is an autoimmune liver disease of unknown etiology characterized by the presence of antimitochondrial antibodies (AMA) in 90 - 95% of patients. AMA are directed against members of 2-oxo-acid dehydrogenase complex, including mainly the E2 subunit of pyruvate dehydrogenase, the E2 subunit of branched chain 2-oxo-acid dehydrogenase complex and the E2 subunit of the oxoglutarate dehydrogenase complex. Apart from AMA, PBC is characterized by the presence of PBC-specific antinuclear antibodies (ANA). The molecular targets of these PBC-specific ANA have been characterized as gp210, lamin B receptor, nucleoporin 62, sp100 and promyelocytic leukemia proteins.

OBJECTIVE

To discuss the molecular diagnostics of PBC in the context of AMA and PBC-specific ANA detection by the use of conventional and 'new' novel technologies.

METHODS

Critical analysis of all published data regarding PBC serology between 1985 and 2007 was performed in order to suggest a diagnostic algorithm for the serological diagnosis of PBC.

RESULTS/CONCLUSIONS

AMA are first detected by indirect immunofluorescence (IIF) on frozen sections of rat liver, kidney and stomach substrates. However, because IIF is time-consuming, labor-intensive and observer-dependent, molecular-based assays such as immunoblot and enzyme-linked immunosorbent assays have been developed with high sensitivity and specificity. Similarly, molecular-based assays have also been developed for the detection of PBC-specific ANA. The latter investigation seems to be of outmost importance because these autoantibodies can be used as a positive tool in the diagnosis of AMA-negative PBC while at the same time identifying a subgroup of PBC patients with more advanced disease. New test systems for the detection of PBC-specific antibodies based on the xMultiple Analyte Profiling Luminex methodology seems to be the future in molecular diagnostics of PBC as it was expected first to decrease the cost and second to speed up an accurate serological profile, although they may decrease further the proportion of AMA-negative PBC cases.

Detection of anti-SP100 antibodies in primary biliary cirrhosis. Comparison of ELISA and immunofluorescence

Primary biliary cirrhosis (PBC) is, which a chronic, autoimmune liver disease. Some patients have antinuclear antibodies anti-Sp100, which are considered to be disease-specific. We compared an enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IIF) for detection of anti-Sp100. The sensitivity of anti-Sp100 determined by ELISA and IIF was 44% and 34%, respectively. Specificity was 99% for ELISA and 98% for IIF, respectively. The positive and negative predictive value (PPV, NPV) for anti-Sp100 determined by ELISA were 98%, 60% and 95%, 56% for IIF respectively. IIF required substantial experience in interpreting subjective patterns, whereas ELISA was more sensitive, cheaper, less time consuming, and produced clear-cut quantitative results.

Serum autoantibodies for the diagnosis and management of autoimmune liver diseases

The spectrum of autoimmune liver diseases (AILD) includes primary biliary cirrhosis, primary sclerosing cholangitis and autoimmune hepatitis. The immunological mechanisms triggering the initiation and perpetuation of AILD remains unknown, while autoantigens are now recognized in most cases, and are generally nontraditional in their widespread distribution. Sensitive and specific methods for the detection of serum autoantibodies in patients affected by AILD represent a challenge for researchers and clinicians who desire to obtain an early and certain diagnosis as well as markers of disease control. To this regard, the use and interpretation of serum autoantibodies in AILD may be seen as paradigmatic for the large gaps in our knowledge based on the lack of true population-based studies. The present review article will critically discuss the available evidence on the use of autoantibody findings in the diagnosis or management of autoimmune liver disease.

Identification of new autoantigens for primary biliary cirrhosis using human proteome microarrays

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease of unknown etiology and is considered to be an autoimmune disease. Autoantibodies are important tools for accurate diagnosis of PBC. Here, we employed serum profiling analysis using a human proteome microarray composed of about 17,000 full-length unique proteins and identified 23 proteins that correlated with PBC. To validate these results, we fabricated a PBC-focused microarray with 21 of these newly identified candidates and nine additional known PBC antigens. By screening the PBC microarrays with additional cohorts of 191 PBC patients and 321 controls (43 autoimmune hepatitis, 55 hepatitis B virus, 31 hepatitis C virus, 48 rheumatoid arthritis, 45 systematic lupus erythematosus, 49 systemic sclerosis, and 50 healthy), six proteins were confirmed as novel PBC autoantigens with high sensitivities and specificities, including hexokinase-1 (isoforms I and II), Kelch-like protein 7, Kelch-like protein 12, zinc finger and BTB domain-containing protein 2, and eukaryotic translation initiation factor 2C, subunit 1. To facilitate clinical diagnosis, we developed ELISA for Kelch-like protein 12 and zinc finger and BTB domain-containing protein 2 and tested large cohorts (297 PBC and 637 control sera) to confirm the sensitivities and specificities observed in the microarray-based assays. In conclusion, our research showed that a strategy using high content protein microarray combined with a smaller but more focused protein microarray can effectively identify and validate novel PBC-specific autoantigens and has the capacity to be translated to clinical diagnosis by means of an ELISA-based method.

Primary biliary cirrhosis and the nuclear pore complex

Experimental models of autoimmune diseases have led to the conclusion that an immune response to nuclear antigens is a sentinel marker for loss of tolerance and potential tissue damage. Various proteins are targets of antinuclear antibodies in a variety of autoimmune diseases, ranging from systemic rheumatologic disorders to diseases affecting specific organs such as the liver. Autoantibodies against specific nuclear constituents have also been used as probes to understand the structure and the function of the targeted components and their relevance to disease pathogenesis. Approximately a quarter of patients with primary biliary cirrhosis (PBC) have antibodies targeting proteins of the nuclear pore complex (NPC), a multi-protein structure that mediates molecular transport across the nuclear envelope. Autoantibodies against the integral membrane glycoprotein gp210 and nucleoporin p62 appear to be highly specific for PBC, an autoimmune disease characterized by progressive destruction of intrahepatic biliary epithelial cells. This review discusses the diagnostic and clinical relevance of anti-NPC antibodies in PBC and the possibility that this autoimmune response may arise as a result of molecular mimicry.

Antinuclear antibodies as ancillary markers in primary biliary cirrhosis

Antimitochondrial antibodies are the serological hallmark of primary biliary cirrhosis (PBC). Besides antimitochondrial antibodies, the autoantibody profile of PBC includes antinuclear antibodies (ANA) which are detectable by indirect immunofluorescence in up to 50% of PBC patients. Two immunofluorescence patterns are considered 'PBC-specific': the multiple nuclear dots and rim-like/membranous patterns. The target antigens of the multiple nuclear dots pattern have been identified as Sp100 and promyelocytic leukemia protein, whereas the rim-like/membranous pattern is given by autoantibodies recognizing multiple proteins such as gp210, nucleoporin p62 and the lamin B receptor. Other ANA, especially those already known in the rheumatological setting, such as anticentromere, anti-SSA/Ro and anti-dsDNA antibodies, can be frequently found in PBC, often coexisting in the same patient. In this article, we will report on recent progress in the antigenic characterization of ANA in PBC, their detection with both traditional assays and Western blot/ELISA with molecularly defined nuclear antigens, and we will discuss their clinical significance.

Liver transplantation in autoimmune liver diseases

Liver transplantation is indicated for terminal phases of autoimmune hepatitis, primary biliary cirrhosis and primary sclerosing cholangitis. Indications for transplantation in autoimmune liver diseases are similar to those used in other acute or chronic liver diseases. Therapeutic advances have reduced the need for transplantation for autoimmune hepatitis and primary biliary cirrhosis but not for primary sclerosing cholangitis. Overall, outcomes of transplantation for autoimmune liver diseases are excellent. However, recurrence of autoimmune liver diseases in the allograft has variable impacts on graft and patient survivals. Treatment of recurrent diseases requires changes in immunosuppression or addition of ursodeoxycholic acid. Among autoimmune liver diseases, only autoimmune hepatitis occurs de novo in recipients transplanted for other diseases. Patients transplanted for autoimmune hepatitis or primary sclerosing cholangitis are at risk for reactivation or de novo onset of ulcerative colitis. Better understanding of the pathogenesis of recurrent autoimmune liver diseases is needed to devise effective means of prevention and treatment.

Primary biliary cirrhosis: What do autoantibodies tell us?

Primary biliary cirrhosis (PBC) is a chronic, progressive, cholestatic, organ-specific autoimmune disease of unknown etiology. It predominantly affects middle-aged women, and is characterized by autoimmune-mediated destruction of small- and medium-size intrahepatic bile ducts, portal inflammation and progressive scarring, which without proper treatment can ultimately lead to fibrosis and hepatic failure. Serum autoantibodies are crucial tools for differential diagnosis of PBC. While it is currently accepted that antimitochondrial antibodies are the most important serological markers of PBC, during the last five decades more than sixty autoantibodies have been explored in these patients, some of which had previously been thought to be specific for other autoimmune diseases.

Autoantibodies as prognostic markers in autoimmune liver disease

Certain autoantibodies in autoimmune liver disease have prognostic implications that are under-utilized and under-developed. The goals of this review are to indicate progress in characterizing the autoantibodies with prognostic connotations and to indicate the feasibility and importance of discovering other markers. Prime source and review articles in English were selected by a Medline search through 2010. Antibodies to soluble liver antigen, actin, liver cytosol type 1, asialoglycoprotein receptor, chromatin, cyclic citrullinated peptide, and uridine glucuronosyltransferases have been associated with the occurrence, severity, and progression of autoimmune hepatitis, and antibodies to Sp100, gp210, and centromere have had similar implications in primary biliary cirrhosis. Antibodies to soluble liver antigen have shown the most promise in autoimmune hepatitis as they have been associated with severe histological changes, long durations of treatment, relapse after drug withdrawal, and high frequency of liver failure. Antibodies to the nuclear rim pore protein, gp210, have shown the most promise in primary biliary cirrhosis as they have been associated with severe interface hepatitis, lobular inflammation, and progression to liver failure. The major limitations of the autoantibodies have been their lack of standardized assays, low negative predictabilities, and fluctuating levels. Performance parameters will improve as critical pathogenic pathways, comprehensive testing batteries, and standardized assays through international exchange workshops are developed. Progress has been made in identifying the serological markers of prognosis in autoimmune liver disease, and they promise to reflect critical disease mechanisms and enhance patient management.

Orthotopic liver transplantation and what to do during follow-up: recommendations for the practitioner

Improvements in surgical technique and the introduction of several new immunosuppressive medications mean that outcome after orthotopic liver transplantation (OLT) has improved continuously over the past 15 years. Given the increasing longevity of patients after OLT, the recognition and prevention of long-term complications after transplantation have become ever more important. With respect to graft function, physicians responsible for the everyday care of patients following transplantation should be particularly aware of the risk of late and chronic rejection episodes and of recurrence of the underlying liver disease. The major challenge of post-transplant care is, however, how best to prevent and manage the long-term adverse effects caused by the immunosuppressive medications prescribed. Screening investigations for early diagnosis of malignancy, strict control of cardiovascular risk factors, preservation of renal function, and prevention of infections are, therefore, fundamental. This Review suggests guidelines for the management of OLT recipients to improve long-term survival, overall outcome and health-related quality of life.

Antimitochondrial antibodies and other antibodies in primary biliary cirrhosis: diagnostic and prognostic value

Antimitochondrial antibodies (AMA) are the serologic cornerstone in the diagnosis of primary biliary cirrhosis (PBC), even if they are not detectable in a proportion of patients, notwithstanding the most sensitive and sophisticated technologies used. To fill in the serologic gap in AMA-negative PBC, there is sound evidence to consider antinuclear antibody (ANA) patterns, such as anti-multiple nuclear dots and anti-membranous/rim-like, as PBC-specific surrogate hallmarks of the disease, and their detection can be considered virtually diagnostic. Furthermore, particular ANA specificities, such as anti-gp210, anti-p62, anticentromere antibodies, and anti-dsDNA, may provide additional diagnostic and prognostic information.

Nuclear envelope protein autoantigens in primary biliary cirrhosis

Antinuclear antibodies are detectable in approximately 50% of subjects with primary biliary cirrhosis (PBC). Most clinical laboratories use indirect immunofluorescence microscopy to detect antinuclear antibodies and two labeling patterns that predominate in PBC are nuclear rim and multiple nuclear dots. Antibodies giving these patterns most often recognize nuclear envelope protein gp210 and nuclear body protein sp100, respectively. Fewer subjects with PBC have autoantibodies giving nuclear rim labeling that recognize nucleoporin p62 and LBR. Gp210 is an integral protein localized to the nuclear pore membranes. Approximately 25% of subjects with PBC have detectable serum anti-gp210 antibodies. The vast majority of anti-gp210 antibodies from patients with PBC recognize a stretch of only 15 amino acids in the carboxyl-terminal tail that faces the nuclear pore complex. Enzyme-linked immunosorbent assays using either recombinant protein expressed in bacteria or chemically synthesized polypeptides have been established to reliably detect these autoantibodies. Although initial studies did not find a correlation between the presence of anti-gp210 antibodies and prognosis in PBC, recent data suggest that the presence of antinuclear envelope protein antibodies correlate with an unfavorable disease course and more rapid progression.

Comparison of two ELISA assays for anti-Sp100 determination

Antibodies to Sp100 have been described not only in primary biliary cirrhosis (PBC), but also in other diseases. Two assays for detection of Sp100 levels by enzyme-linked immunosorbent assay (ELISA) have been compared in a cohort of patients from our area: (a) Sp100 kit produced by IMTEC, Immunodiagnostica GmbH, and (b) Quanta Lite Sp100 kit produced by INOVA Diagnostics. We analyze here the correlation between the two assays and compare their efficiency in diagnosing PBC. We also comment on the exceptions derived from reactivity with other diseases. We studied 78 sera by IIF with the typical multiple nuclear dots (MND) pattern from patients who suffered from PBC, hepatopathies different from PBC, systemic lupus erythematosus (SLE), other connective tissue diseases (CTD), skeletal diseases, lung diseases, hematological disorders, a miscellaneous group, and a healthy IIF negative control group. The tests work equally well despite their different quantification system: (a) it is based on a standard curve; and (b) it is based on a single-point antigen-specific calibration. Some discrepancies could be explained by differences in the immunodominant epitope used in the ELISA. The main finding of this study is that the presence of MND/Sp100-positive antibodies were detected not only in hepatic diseases, mainly PBC, but also in other clinical conditions, confirmed by both tests. Diagnosis of PBC must be established in the right clinical context, because other diseases recognizing the same epitope, mainly SLE, may also show high Sp100 levels. Sera from PBC patients with antimitochondrial antibodies (AMA) showed higher anti-Sp100 than the AMA-negative group.

De novo autoimmune hepatitis following liver transplantation for primary biliary cirrhosis

De novo autoimmune hepatitis (AIH) is a rare disorder first described in 1998. It appears in patients with liver transplants for non-AIH etiology. The few cases in the literature make it a little known entity due to mechanisms that are unclear. We present the case of a woman with a liver transplant whose graft developed de novo AIH. Diagnosed with primary biliary cirrhosis, the patient underwent liver transplantation for refractory pruritus. Sixteen months after transplantation, we detected alterations in the hepatic profile with hypertransaminasemia and elevated alkaline phosphatase, together with elevated antinuclear antibodies. IgG levels were normal. Histological findings indicated AIH. The patient responded rapidly to treatment with prednisolone and azathioprine. De novo AIH in patients transplanted for PBC may cause graft dysfunction. This report also analyzes the case with respect to the other four reported cases, discussing etiologic hypotheses.

Role of auto-antibodies for the diagnosis of chronic cholestatic liver diseases

Auto-antibodies are an integral part of the diagnostic armentarium in chronic cholestatic liver disorders, such as primary sclerosing cholangitis (PSC), primary biliary cirrhosis (PBC),auto-immune cholangitis, or overlap syndromes among these disorders. However, care should be taken not to overestimate the diagnostic specificity. Auto-antibodies to mitochondrial antigens(AMAs) with reactivity to the E2 subunit of the pyruvate dehydrogenase complex represent the hallmark antibody for the diagnosis of PBC, whereas antinuclear antibodies (ANAs)with low disease specificity are found in up to 50% of these sera. Antibodies that recognize nuclear envelope proteins exert a similarly high diagnostic specificity as AMA in PBC but occur at a rather low prevalence. The role of auto-antibodies is less well-studied for patients with PSC, but there is growing evidence that only antineutrophil cytoplasmic antibodies(ANCAs) are of relevant diagnostic significance. In contrast, auto-antibodies-particularlyAMAs-do not contribute to the diagnosis of auto-immune cholangitis, whereas ANCAs,ANAs, smooth muscle antibodies, and AMAs are of varying significance in PBC-auto-immune hepatitis (AIH) or PSC-AIH overlap syndromes. It has been widely accepted that the course of the auto-antibody serum end point titers are not suited for the clinical management of patients with chronic cholestatic liver disorders. Additionally, auto-antibodies in these disorders usually do not contribute to the immunopathogenesis of the disease.

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Nuclear pore complex oxalate binding protein p62: expression in different kidney disorders

BACKGROUND

Urolithiasis is a multifactorial process that starts with the formation of microcrystals in the urine and terminates as mature renal calculi. The oxalate binding protein plays a vital role in the transport of oxalate. The physiological significance of the presence of oxalate binding protein in the nuclear pore complex is not well understood.

METHODS

The nuclear envelope was extracted from human cadaver kidneys. 14C oxalate was labeled, nuclear pore complex proteins were extracted and loaded onto Sephadex G-200, and further purified in DEAE-Sephadex A-50 column. The radioactive protein peak was pooled, concentrated and checked for purity in SDS-PAGE. The purified protein showed cross-reactivity with the monoclonal antibody (MAb 414) and was homogeneous. Urine samples of healthy individuals with no history of kidney disease served as control. Blood and urine samples were collected from kidney and autoimmune disorder patients and checked for the expression of p62 protein by ELISA.

RESULTS

Extracted and purified nuclear pore complex oxalate binding protein had a molecular weight of 62 kDa. A threefold increase in oxalate excretion was observed in hyperoxaluric patients compared to control subjects. The protein expression was found to be higher in hyperoxaluric patients vs. controls, chronic renal failure (CRF) and acute renal failure (ARF), whereas decreased expression was observed in nephrotic syndrome (NS) patients. p62 autoantibodies was observed in hyperoxaluria (HO), systemic lupus erythematosus (SLE) and primary biliary cirrhosis (PBC), whereas it was absent in controls.

CONCLUSION

Increased expression of p62 may be due to membrane damage induced by oxalate stress, and may be used as a diagnostic marker. This study also confirms the presence of p62 autoantibodies in HO patients.

Long-term outcome of liver transplantation for autoimmune hepatitis

BACKGROUND

Liver transplantation is the final therapeutic option for about 10% of patients with autoimmune hepatitis (AIH) who do not respond to medical therapy. The aim of this study was to evaluate the long-term outcome in serologically defined subgroups of AIH after transplantation.

METHODS

Pre- and post-transplantation data of 28 patients with AIH transplanted between 1987 and 1999 were retrospectively analyzed and compared with 24 patients, who underwent liver transplantation because of Wilson's disease and glycogen storage disease type 1.

RESULTS

Serological analyses identified patients with AIH type 1 (n = 13), type 2 (n = 5), and type 3 (n = 10). The 5-yr patient survival rate after liver transplantation was 78.2%, which was not significantly different from the control group. Six AIH patients and four control patients required re-transplantation because of initial non-function, chronic rejection or AIH recurrence. Patients transplanted for AIH (88%) had more episodes of acute rejection when compared with patients transplanted for genetic liver diseases (50%). Clinical and histological features of chronic rejection were present in four patients, which did not differ significantly from the controls. Recurrence of AIH was diagnosed in nine patients (32%) based upon the presence of autoantibodies, increased gamma-globulins, steroid dependency, and histological evidence of chronic hepatitis. These combined features were not found in any of the controls.

CONCLUSIONS

Our data do not suggest that AIH subtypes influence prognosis after liver transplantation. Despite a high frequency of acute cellular rejection episodes and disease recurrence, transplantation for AIH has a 5-yr survival rate, which does not differ from that observed in patients transplanted for genetic liver diseases.

Primary biliary cirrhosis and autoimmune cholangiopathy

AMA are detected in the serum of 92% to 95% of patients with PBC using indirect immunofluorescent methods. AIC is the term used to describe the 5% to 8% of AMA-negative PBC patients who uniformly have ANA and SMA. Recent applications of more sensitive and specific tests to detect serum AMA have shown that most, if not all, patients with AIC actually do have AMA. Emerging evidence that AMA and mitochondrial autoantigens play important roles in the immunopathogenesis of NSDC also suggests that AIC and PBC are likely to be a single disease, exhibiting variation in the types of autoantibodies and in both the concentrations and immunoglobulin isotypes of AMA.

Primary biliary cirrhosis--presentation and diagnosis

Primary biliary cirrhosis is predominantly seen in middle-aged women. Typical symptoms are fatigue, pruritus, and abdominal pain. Jaundice develops in the endstage disease. At presentation, about 40% of the patients are asymptomatic, but 30% to 50% already have hepatomegaly, and 15% present with splenomegaly. Even patients with fully developed liver cirrhosis may be free of symptoms. Abnormal physical signs and advanced histological stage are more frequent in symptomatic than in asymptomatic patients. Fatigue, pruritus, and Sjögren's syndrome are more common in women than men, but other signs and symptoms do not differ in the two sexes. PBC is associated with a large variety of other diseases, like arthropathy, CREST syndrome, autoimmune thyroiditis, and so on, which in addition will or will not produce symptoms. Hepatocellular carcinoma is a rare complication in women, but more frequent in men. Diagnosis can be established by the triad antimitochondrial antibodies (AMA), cholestatic indices, and liver histology, diagnostic or compatible with PBC. When AMA are not detected, then antinuclear antibodies (autoantibodies against gp.210 and others) can be detected in 50% of AMA-negative patients. AMA titers do not correlate with the course of the disease nor histological progression. After liver transplantation, AMA recur in nearly 100%. The liver enzyme pattern in PBC patients is cholestatic: alkaline phosphatase and gammaglutamyltransferase increase to 10 or more times the upper limit of normal. The amount of enzymes does not correlate with disease progression or stage of the disease. The only prognostic factor in PBC is serum bilirubin. AMA-negative patients account for about 10% to 15%. Routine biochemical tests are not different from AMA-positive patients, but usually higher ANA, SMA, and IgG concentrations are detected. Histologically, it is PBC. The overlap-syndrome, autoimmune hepatitis-PBC presents with the histological features of autoimmune hepatitis and PBC, with AMA, ANA, or SMA. Imaging procedures are not helpful for the diagnosis of PBC, except for liver histology. Histologically, four different stages can be assessed, ranging from florid bile duct lesions, ductular proliferation, and fibrosis to liver cirrhosis. Liver histology is of interest for the assessment of the diagnosis and for staging of the disease.

Antinuclear antibodies specific for primary biliary cirrhosis

The serological hallmark of primary biliary cirrhosis (PBC) is the presence of antimitochondrial antibodies. However, antinuclear antibodies (ANA) are also detectable in approximately 50% of subjects with PBC. Most clinical laboratories use indirect immunofluorescence microscopy to detect ANA and two labeling patterns that predominate in PBC are 'punctate nuclear rim' and 'multiple nuclear dots.' Work over the past several years has shown that antibodies giving these patterns most often recognize nuclear pore membrane protein gp210 and nuclear body protein sp100, respectively. These ANA are highly specific for PBC and detected in approximately 25% of patients. Less frequently, ANA apparently unique to PBC recognize other proteins of the nuclear envelope and nuclear bodies. While antibodies against gp210, sp100 and some other nuclear proteins are very specific to PBC and may therefore be useful diagnostic markers, their connection to pathogenesis remains to be elucidated.

Autoantibodies against nuclear pore complexes are associated with more active and severe liver disease in primary biliary cirrhosis

BACKGROUND/AIMS

Antibodies against nuclear pore complexes (NPCs) have been detected in primary biliary cirrhosis (PBC), but their clinical relevance is still unsettled.

METHODS

We tested sera from 171 consecutive PBC patients and 230 control subjects (149 with autoimmune or viral liver diseases, 28 with systemic lupus erythematosus, and 53 healthy) by immunoblotting for antibodies against purified human NPCs.

RESULTS

Antibodies to NPCs were detected in 27% of the patients with PBC, were highly specific (97%), and were not associated with antimitochondrial antibodies. Their prevalence was higher in symptomatic patients (36 vs. 16%, P < 0.01) and was associated (P < 0.001) with more severe disease, as assessed by the presence of cirrhosis or its complications (13% prevalence in patients without cirrhosis, 31% in uncomplicated, and 54% in complicated cirrhosis), or by the application of the Mayo prognostic model (12% in the lowest, 21% in the median, 47% in the highest score tertile). Positive patients had higher levels of serum bilirubin (2.2 +/- 3.7 vs. 1.0 +/- 1.1 mg/dl, P < 0.01) and more marked inflammatory infiltrates on liver biopsy (P < 0.05).

CONCLUSIONS

Autoantibodies to NPCs are more prevalent in PBC patients than in controls and are strongly associated with more active and severe disease.

Autoantigens in primary biliary cirrhosis

The automimmune liver disease primary biliary cirrhosis (PBC) is characterised by serum autoantibodies directed at mitochondrial and nuclear antigens (seen in most patients and a subset of patients, respectively). The antimitochondrial antibodies (AMA) characteristic of PBC are directed at members of the 2-oxoacid dehydrogenase components of multienzyme complexes; in particular, the E2 and E3 binding protein (E3BP) components of the pyruvate dehydrogenase complex (PDC). The presence of autoantibodies reactive with PDC-E2 and/or E3BP is strongly predictive of the presence of PBC. Therefore, the detection of these antibodies plays a very important role in the diagnosis of PBC. Originally demonstrated using immunofluorescence approaches, AMA can now be detected by the use of commercially available enzyme linked immunosorbent assays (ELISAs). Although the ELISA based approaches have advantages in terms of laboratory practicality, they are slightly less sensitive for the diagnosis of PBC than immunofluorescence (occasional patients with PBC show reactivity with PDC related antigens not present in the antigen preparations available for use with ELISA). Therefore, immunofluorescence should continue to be available as a complementary diagnostic test for use in occasional patients. In a subset of patients with PBC, autoantibodies are directed at increasingly well characterised nuclear antigens. Antinuclear antibody (ANA) positive patients are typically AMA negative. There are no significant differences in disease phenotype between AMA positive and AMA negative groups. At present, the clinical detection of ANA is mostly by Hep2 immunofluorescence, although ELISA kits for individual nuclear antigens are increasingly becoming available.

Autoimmune tests in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is characterized by an immune mediated, irreversible destruction of the small intrahepatic bile ducts leading to progressive liver cirrhosis and frequently to liver failure. The course of the disease is variable and an early diagnosis is desirable to identify individuals with rapidly progressing disease, to initiate adequate therapeutic measures and to evaluate the necessity of liver transplantation. Serological tests represent the single most important diagnostic feature of PBC because liver histology, biochemistry, or clinical syndrome alone are not reliable in this respect. The molecular definition of the autoantigen targets of antimitochondrial antibodies (AMA) has resulted in the development of reproducible and effective serological testing strategies. AMA directed against the ketoacid dehydrogenase complex are highly disease-specific but not directed against liver-specific target structures. Despite a high disease specificity, their usefulness for predicting the course of disease, the timing of liver transplantation, or disease recurrence after transplantation is limited. The realization that about 5% of patients with PBC do not display AMA has led to the identification of PBC-specific antinuclear autoantibodies directed against the nuclear pore complex and other targets. The overlap of PBC with autoimmune hepatitis and primary sclerosing cholangitis represents a diagnostic challenge in which autoantibody determinations play a central role and contribute to the administration of suitable treatment options.

Autoimmune cholangiopathy

Currently available evidence is insufficient to classify PBC and AIC as separate diseases. The ultimate answer to the question of whether AIC, defined as AMA-negative PBC with ANA or SMA, is a disease distinct from AMA-positive PBC with or without ANA will require a detailed comparison of etiologic factors and pathogenetic mechanisms, once they are elucidated. It is intriguing to consider the suggestion of Heathcote that the term autoimmune cholangitis be adopted to describe PBC with or without detectable AMA. However, it is improbable that the venerable term PBC will be supplanted. Hepatologists will probably continue to use the terms AIC and AMA-negative PBC interchangeably, with little risk of being misunderstood.