High prevalence of antibodies to recombinant CENP-B in primary biliary cirrhosis: nuclear immunofluorescence patterns and ELISA reactivities

The prognostic value of anti-gp210 and anti-centromere antibodies in patients with primary biliary cholangitis: Enhancing the prognostic utility on the GLOBE scoring system

BACKGROUND

Positivity for anti-gp210 and anti-centromeric antibodies (ACA) in patients with primary biliary cholangitis (PBC) have been associated with the progression of liver failure and portal hypertension (PH), respectively. The value of combining risk autoantibody assessments with prognostic scoring systems in improving risk assessment in patients with PBC remains unclear.

AIMS

To investigate the prognostic significance of various combinations of anti-gp210 and ACA statuses and their enhancing the prognostic utility on the GLOBE scoring system.

METHODS

Stepwise Cox regression was used to estimate the relationship between anti-gp210 antibodies or ACA and liver transplant (LT)-free survival. The GLOBE scoring system was used to stratify the patients.

RESULTS

A total of 1412 patients with confirmed PBC were included in the study. The anti-gp210+ status was a significant risk factor for LT/liver-related death, whereas the ACA+ status was a significant risk factor for variceal bleeding (P = 0.002 and 0.007, respectively). The anti-gp210 + ACA + status was a risk indicator for the entire cohort independent of the GLOBE score (P = 0.001, hazard ratio [HR]: 2.649, 95 % confidence interval [CI]: 1.492-4.703) and liver stiffness measurements (LSM; P = 0.039, HR: 4.969, 95 % CI: 1.088-22.692). A significant difference was observed in the area under the receiver operating characteristic curve between the fitted scoring model (consisting of the GLOBE score, anti-gp210 + ACA+ status, and albumin level) and the GLOBE scoring system alone (P = 0.034). When enrolled patients were classified as high-, medium-, and low-risk by the GLOBE scoring system (1.8 and 0.5), the anti-gp210 + ACA+ status was associated with a 1.6- and 3.3-fold higher 5-year incidence of LT/liver-related death in the high- and medium-risk groups, respectively, in comparison with the anti-gp210 + ACA- cases. The anti-gp210 + ACA+ status was also a risk indicator for the presentation of the hepatic failure phenotype in comparison with the anti-gp210- status (P = 0.007, odds ratio [OR]: 6.419, 95 % CI: 1.645-25.042), and the presentation of PH phenotype in comparison with the anti-ACA- status (OR: 3.473, 95 % CI: 1.328-9.018, P = 0.011).

CONCLUSION

The anti-gp210 + ACA+ status was an independent prognostic marker that could predict a poor prognosis in patients with PBC at diagnosis and may further optimise risk stratification in combination with the GLOBE scoring system.

Presence of anti-gp210 or anti-sp100 antibodies in AMA-positive patients may help support a diagnosis of primary biliary cholangitis

BACKGROUND

Anti-mitochondrial antibody (AMA) positivity is not always associated with primary biliary cholangitis (PBC). We aimed to determine the additional value of anti-sp100 or anti-gp210 antibody in AMA-positive patients for PBC.

METHODS

Patients (n = 190) and healthy donors (n = 50) were evaluated for AMA, anti-gp210 and anti-sp100 antibodies by ELISA. Antibody frequencies in cohorts and performance characteristics in some patients categorized as 'definitive-', 'probable-', and 'no PBC' were determined following review of their charts.

RESULTS

Of the patients (n = 190), 38.4% were AMA-positive (n = 73) and 61.6% AMA-negative (n = 117). Frequency of anti-sp100 or anti-gp210 antibody was 17.8%, 2.6%, and 0% in AMA-positive, AMA-negative and healthy controls, respectively. Clinical data was available for 63 of 73 AMA-positive patients with 28.6%, 22.2%, and 49.2% categorized as definite, probable, and no PBC, respectively. Patients with definite PBC had higher mean levels of AMA and frequencies of sp100 or gp210 antibody compared to other groups. Sensitivities were low (anti-sp100: 18.8% and anti-gp210: 16.7%) with specificities above 98.0% for both.

CONCLUSION

AMA-positive patients positive for anti-sp100 or anti-gp210 antibody were more likely to have a diagnosis of definite or probable PBC than those with AMA alone. Use of all tests is likely to improve characterization of patients at-risk for PBC.

Immunologic Responses and the Pathophysiology of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease with a female predisposition and selective destruction of intrahepatic small bile ducts leading to nonsuppurative destructive cholangitis. It is characterized by seropositivity of antimitochondrial antibodies or PBC-specific antinuclear antibodies, progressive cholestasis, and typical liver histologic manifestations. Destruction of the protective bicarbonate-rich umbrella is attributed to the decreased expression of membrane transporters in biliary epithelial cells (BECs), leading to the accumulation of hydrophobic bile acids and sensitizing BECs to apoptosis. A recent X-wide association study reveals a novel risk locus on the X chromosome, which reiterates the importance of Treg cells.

Antigen-driven selection of antibodies against SSA, SSB and the centromere 'complex', including a novel antigen, MIS12 complex, in human salivary glands

OBJECTIVES

Recent evidences have revealed that anti-SSA/SSB antibodies, the major autoantibodies in Sjögren's syndrome (SS), are produced in salivary glands. This study aims to clarify overall of autoantibody production at lesion site, including anti-centromere antibody (ACA)-positive SS.

METHODS

Antibodies of antibody-secreting cells in human salivary glands were produced as recombinant antibodies. The reactivity of these antibodies and their revertants were investigated by ELISA and newly developed antigen-binding beads assay, which can detect conformational epitopes. The target of uncharacterised antibodies was identified by immunoprecipitation and mass spectrometry. Autoantibody-secreting cells in salivary gland tissue were identified by immunohistochemistry using green fluorescent protein-autoantigen fusion proteins.

RESULTS

A total of 256 lesion antibodies were generated, and 69 autoantibodies including 24 ACAs were identified among them. Beads assay could detect more autoantibodies than ELISA, suggesting autoantibodies target to antigens with native conformation. After somatic hypermutations were reverted, autoantibodies drastically decreased antigen reactivity. We showed that MIS12 complex, a novel target of ACA, and CENP-C are major targets of ACA produced in salivary glands by examining cloned antibodies and immunohistochemistry, whereas few anti-CENP-B antibodies were detected. The target profiling of serum ACA from 269 patients with SS, systemic sclerosis (SSc), primary biliary cirrhosis (PBC) and healthy controls revealed that ACA-positive patients have antibodies against various sites of centromere complex regardless of disease.

CONCLUSION

We showed direct evidences of antigen-driven maturation of anti-SSA/SSB antibody and ACA in SS lesion. ACA recognises centromere 'complex' rather than individual protein, and this feature is common among patients with SS, SSc and PBC.

Anti-centrosome antibodies: Prevalence and disease association in Chinese population

Anti-centrosome antibodies are rare findings with undefined clinical significance in clinical research. We aimed at investigating the prevalence and clinical significance of anti-centrosome antibodies in Chinese population. Testing results of total of 281,230 ANA-positive sera were retrospectively obtained from West China Hospital Sichuan University in China between 2008 and 2017. We retrospectively collected and analysed the clinical and laboratory data of the patients with positive anti-centrosome antibody. Of the 356 453 patients tested, 281 230 patients had positive antinuclear antibodies (ANAs, 78.9%), but only 78 patients with positive anti-centrosome antibodies (0.022%), of which 74.4% are females. Diagnoses were established in 69 of 78 patients: 37 cases were autoimmune diseases, mainly including undifferentiated connective tissue diseases (UCTD, 9/37), rheumatoid arthritis (RA, 6/37), Sjögren's syndrome (SS, 5/37) and primary biliary cirrhosis (PBC, 5/37), and the remaining were other autoimmune conditions. The most frequent clinical symptoms of the anti-centrosome-positive patients were arthralgia and eyes and mouth drying. Additionally, 86.7% of anti-centrosome antibodies were not associated with other ANA profiles; however, when associated, the most frequent ANA was anti-U1RNP. Anti-centrosome antibodies are featured by a low prevalence and female gender predominance. They are correlated with some specific diseases, both autoimmune diseases, especially UCTD, RA, SS and PBC, and non-autoimmune diseases, such as infection and cancer, which suggests that they might be potential supporting serological markers of these diseases.

Anti-nuclear autoantibodies in systemic sclerosis : News and perspectives

Systemic sclerosis is a connective tissue disorder characterized by microvascular damage and excessive fibrosis of the skin and internal organs. One hallmark of the immunological abnormalities in systemic sclerosis is the presence of anti-nuclear antibodies, which are detected in more than 90% of patients with systemic sclerosis. Anti-centromere antibodies, anti-DNA topoisomerase I antibodies, and anti-RNA polymerase III antibodies are the predominant anti-nuclear antibodies found in systemic sclerosis patients. Other systemic sclerosis-related anti-nuclear antibodies include those targeted against U3 ribonucleoprotein, Th/To, U11/U12 ribonucleoprotein, and eukaryotic initiation factor 2B. Anti-U1 ribonucleoprotein, anti-Ku antibodies, anti-PM-Scl, and anti-RuvBL1/2 antibodies are associated with systemic sclerosis overlap syndrome. Anti-human upstream binding factor, anti-Ro52/TRIM21, anti-B23, and anti-centriole antibodies do not have specificity to systemic sclerosis, but are sometimes detected in sera from patients with systemic sclerosis. Identification of each systemic sclerosis-related antibody is useful to diagnose and predict organ involvement, since the particular type of systemic sclerosis-related antibodies is often predictive of clinical features, severity, and prognosis. The clinical phenotypes are largely influenced by ethnicity. Currently, an immunoprecipitation assay is necessary to detect most systemic sclerosis-related antibodies; therefore, the establishment of an easy, reliable, and simple screening system is warranted.

Pathophysiology of primary biliary cholangitis

Primary biliary cholangitis is a prototypical autoimmune disease characterized by an overwhelming female predominance, a distinct clinical phenotype, and disease specific anti-mitochondrial antibodies targeted against a well-defined auto-antigen. In a genetically susceptible host, multi-lineage loss of tolerance to the E2 component of the 2-oxo-dehydrogenase pathway and dysregulated immune pathways directed at biliary epithelial cells leads to cholestasis, progressive biliary fibrosis, and cirrhosis in a subset of patients. Several key insights have shed light on the complex pathogenesis of disease. First, characteristic anti-mitochondrial antibodies (AMAs) target lipoic acid containing immunodominant epitopes, particularly pyruvate dehydrogenase complex (PDC-E2), on the inner mitochondrial membrane of BECs. Next, breakdown of the protective apical bicarbonate rich umbrella may sensitize BECs to aberrant apoptotic pathways leaving the antigenic PDC-E2 epitope immunologically tact within an apoptotic bleb. A multi-lineage immune response ensues characterized by an imbalance between effector and regulatory activity resulting in progressive and self-perpetuating biliary injury. Genome wide studies shed light on important pathways involved in disease, key among them being IL-12. Epigenetic mechanisms and microRNAs may play help shed light on the missing heritability and female preponderance of disease. Taken together, these findings have dramatically advanced our understanding of disease and may lead to important therapeutic advances.

Making Sense of Autoantibodies in Cholestatic Liver Diseases

Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are the most common chronic cholestatic liver diseases (CLD) in adults and are associated with immune mechanisms. PBC is considered a model autoimmune disease, and more than 90% of patients present very specific autoantibodies against mitochondrial antigens. Whether PSC should be considered an autoimmune or merely immune-mediated disease is still under debate. This review addresses the clinical relevance of autoantibodies in CLD and their pathogenic mechanisms and illustrates the technology available for appropriate autoantibody detection.

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

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

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.

Anti-centromere antibody is an independent risk factor for chronic kidney disease in patients with primary biliary cirrhosis

BACKGROUND

Anti-centromere antibody (ACA), a typical autoantibody of systemic sclerosis, is also detected in primary biliary cirrhosis (PBC). However, its pathogenic role is not fully understood. The aim of this study was to determine the association between ACA and kidney function in PBC.

METHODS

A cohort of 37 patients diagnosed as having PBC from July 2001 to November 2011 at Yokosuka Kyosai Hospital was retrospectively analyzed for a follow-up period of 12 months. The annual rate of estimated glomerular filtration rate (eGFR) decline within 1 year after the diagnosis was evaluated. The factors associated with eGFR decline were evaluated by linear regression analysis and logistic regression analysis.

RESULTS

Overall, 37 PBC patients were included, of whom 12 (32%) had ACA. The patients with ACA had a lower eGFR (65.9 ± 19.9 vs. 80.3 ± 12.1 mL/min/1.73 m(2), P = 0.01), a higher likelihood of chronic kidney disease (CKD) (58 vs. 4%, P = 0.0005), and a higher rate of annual eGFR decline (-4.3 ± 5.1 vs. 0.2 ± 4.6 mL/min/year, P = 0.01) than those without ACA. Univariate regression analysis and multivariate regression analysis adjusted for potential cofounders including age, eGFR, sex, diabetes mellitus, and hypertension showed that ACA was associated with eGFR decline (P = 0.011 and 0.017, respectively). Multivariate logistic regression analysis adjusted for these cofounders showed that ACA was associated with eGFR decline less than -4 mL/min/year (odds ratio 7.21, 95% confidence interval 0.93-56.1, P = 0.059).

CONCLUSIONS

ACA is an independent risk factor for CKD in PBC. Evaluation of ACA and kidney function is necessary to prevent CKD progression in PBC patients.

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.

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.

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: 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.

Clinical and serological evaluation of a novel CENP-A peptide based ELISA

Introduction

Anti-centromere antibodies (ACA) are useful biomarkers in the diagnosis of systemic sclerosis (SSc). ACA are found in 20 to 40% of SSc patients and, albeit with lower prevalence, in patients with other systemic autoimmune rheumatic diseases. Historically, ACA were detected by indirect immunofluorescence (IIF) on HEp-2 cells and confirmed by immunoassays using recombinant CENP-B. The objective of this study was to evaluate a novel CENP-A peptide ELISA.

Methods

Sera collected from SSc patients (n = 334) and various other diseases (n = 619) and from healthy controls (n = 175) were tested for anti-CENP-A antibodies by the novel CENP-A enzyme linked immunosorbent assay (ELISA). Furthermore, ACA were determined in the disease cohorts by IIF (ImmunoConcepts, Sacramento, CA, USA), CENP-B ELISA (Dr. Fooke), EliA^® CENP (Phadia, Freiburg, Germany) and line-immunoassay (LIA, Mikrogen, Neuried, Germany). Serological and clinical associations of anti-CENP-A with other autoantibodies were conducted in one participating centre. Inhibition experiments with either the CENP-A peptide or recombinant CENP-B were carried out to analyse the specificity of anti-CENP-A and -B antibodies.

Results

The CENP-A ELISA results were in good agreement with other ACA detection methods. According to the kappa method, the qualitative agreements were: 0.73 (vs. IIF), 0.81 (vs. LIA), 0.86 (vs. CENP-B ELISA) and 0.97 (vs. EliA^® CENP). The quantitative comparison between CENP-A and CENP-B ELISA using 265 samples revealed a correlation value of rho = 0.5 (by Spearman equation). The receiver operating characteristic analysis indicated that the discrimination between SSc patients (n = 131) and various controls (n = 134) was significantly better using the CENP-A as compared to CENP-B ELISA (P < 0.0001). Modified Rodnan skin score was significantly lower in the CENP-A negative group compared to the positive patients (P = 0.013). Inhibition experiments revealed no significant cross reactivity of anti-CENP-A and anti-CENP-B antibodies. Statistically relevant differences for gender ratio (P = 0.0103), specific joint involvement (Jaccoud) (P = 0.0006) and anti-phospholipid syndrome (P = 0.0157) between ACA positive SLE patients and the entire SLE cohort were observed.

Conclusions

Anti-CENP-A antibodies as determined by peptide ELISA represent a sensitive, specific and independent marker for the detection of ACA and are useful biomarkers for the diagnosis of SSc. Our data suggest that anti-CENP-A antibodies are a more specific biomarker for SSc than antibodies to CENP-B. Furthers studies are required to verify these findings.

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.

The value of antinuclear antibodies in primary biliary cirrhosis

OBJECTIVE

Although autoantibodies have been used for the diagnosis of primary biliary cirrhosis (PBC), their role has not been clarified. In this study, we try to explore the value of gp210 antibody and anti-centromere antibodies (ACA) in PBC.

METHODS

Anti-gp210 and ACA were tested in 140 PBC patients by ELISA and indirect immunofluorescence respectively. Their association with clinical, pathological data and prognosis was analysed.

RESULTS

30.5% of PBC patients had positive anti-gp210 antibody and 29.2% had ACA. The anti-gp210 antibody positive group had higher Mayo risk scores and lower serum albumin levels compared to the negative one. Patients with positive anti-gp210 antibody were more likely to develop hepatic failure (p<0.05, OR=9.8460, 95% CI: 1.067-90.901) than patients with negative anti-gp210 antibody. More patients with positive ACA developed portal hypertension than patients with negative ACA (p<0.05, OR=9.259; 95% CI: 1.027-88.410). Furthermore, concurrent Sjögren's syndrome (SjS) and PBC was significantly more likely in the ACA positive group than in the negative ones (68.4% in ACA positive group, 20.7% in ACA negative group p<0.001).

CONCLUSIONS

Both anti-gp210 antibody and ACA are related to severe disease course and poor prognosis. For PBC patients with positive ACA, further examinations should be made to detect underlying SjS.

Antibodies to SS-A/Ro-52kD and centromere in autoimmune liver disease: a clue to diagnosis and prognosis of primary biliary cirrhosis

BACKGROUND

Primary biliary cirrhosis (PBC) may be associated with various rheumatological disorders.

AIM

To investigate the frequency and significance of 'rheumatological' antinuclear antibodies in the field of autoimmune chronic liver disease, with special regard to PBC.

METHODS

We studied 105 patients with PBC, 162 autoimmune liver disease controls (type 1 and 2 autoimmune hepatitis, primary sclerosing cholangitis), 30 systemic lupus erythematosus and 50 blood donors. Sera were tested for the presence of antibodies to extractable nuclear antigens (anti-ENA) by counterimmunoelectrophoresis, enzyme-linked and immunoblot (IB) assay, and for the presence of anti-centromere antibodies (ACA) by indirect immunofluorescence on HEp-2 cells and IB.

RESULTS

The overall prevalence of IB-detected anti-ENA in PBC (30%) was higher than in type 1 autoimmune hepatitis (2.5%, P < 0.0001), type 2 autoimmune hepatitis (0%, P < 0.0001) and primary sclerosing cholangitis (11.5%, P = 0.006) and lower than in systemic lupus erythematosus (53%, P = 0.03). The most frequent anti-ENA reactivity in PBC was anti-SSA/Ro-52kD (28%). ACA were detected by IB in 21% PBC patients and never in the other subjects (P < 0.0001). Anti-SS-A/Ro/52kD positive PBC patients had at the time of diagnosis a more advanced histological stage (P = 0.01) and higher serum levels of bilirubin (P = 0.01) and IgM (P = 0.03) compared with negative ones.

CONCLUSIONS

In the autoimmune liver disease setting, anti-SS-A/Ro-52kD and ACA have a high specificity for PBC and can thus be of diagnostic relevance in anti-mitochondrial antibodies negative cases. If confirmed in further studies with adequate follow-up, anti-SS-A/Ro-52kD antibodies might identify PBC patients with a more advanced and active disease.

Anti-gp210 and anti-centromere antibodies are different risk factors for the progression of primary biliary cirrhosis

The predictive role of antinuclear antibodies (ANAs) remains elusive in the long-term outcome of primary biliary cirrhosis (PBC). The progression of PBC was evaluated in association with ANAs using stepwise Cox proportional hazard regression and an unconditional stepwise logistic regression model based on the data of 276 biopsy-proven, definite PBC patients who have been registered to the National Hospital Organization Study Group for Liver Disease in Japan (NHOSLJ). When death of hepatic failure/liver transplantation (LT) was defined as an end-point, positive anti-gp210 antibodies (Hazard ratio (HR) = 6.742, 95% confidence interval (CI): 2.408, 18.877), the late stage (Scheuer's stage 3, 4) (HR = 4.285, 95% CI:1.682,10.913) and male sex (HR = 3.266, 95% CI: 1.321,8.075) were significant risk factors at the time of initial liver biopsy. When clinical progression to death of hepatic failure/LT (i.e., hepatic failure type progression) or to the development of esophageal varices or hepatocellular carcinoma without developing jaundice (Total bilirubin < 1.5 mg/dL) (i.e., portal hypertension type progression) was defined as an end-point in the early stage (Scheuer's stage 1, 2) PBC patients, positive anti-gp210 antibodies was a significant risk factor for hepatic failure type progression [odds ratio (OR) = 33.777, 95% CI: 5.930, 636.745], whereas positive anti-centromere antibodies was a significant risk factor for portal hypertension type progression (OR = 4.202, 95% CI: 1.307, 14.763). Histologically, positive anti-gp210 antibodies was most significantly associated with more severe interface hepatitis and lobular inflammation, whereas positive anticentromere antibodies was most significantly associated with more severe ductular reaction.

CONCLUSION

These results indicate 2 different progression types in PBC, hepatic failure type and portal hypertension type progression, which may be represented by positive-anti-gp210 and positive-anticentromere antibodies, respectively.

A case of limited cutaneous systemic sclerosis developing anti-mitochondria antibody positive primary biliary cirrhosis after acute myocardial infarction

In this report, we present a 63-year-old woman who had limited cutaneous systemic sclerosis and subsequently developed typical primary biliary cirrhosis after an acute myocardial infarction. The patient initially developed Raynaud's phenomenon, and 4 years later visited the clinic in 1994 complaining of abdominal distress, xerostomia, and xerophthalmia. A diagnosis of limited cutaneous systemic sclerosis was based on Raynaud's phenomenon, sclerodactyly and anti-centromere antibodies. She was also found to have anti-inositol 1,4,5-trisphosphate receptor 3 (IP(3)R3) antibodies, but anti-mitochondrial antibodies were only weakly positive. Seven years later, she developed vertigo and nausea, and was hospitalized due to complaints of an oppressive sensation of the anterior chest. Electrocardiogram results showed a reduction of R waves and ST segment elevation in II, III, and aVf leads. Coronary angiography showed 99% obstruction of the left anterior descending artery and 50% of stenosis of the right coronary artery. Three years later, the patient was noted to have anti-mitochondrial antibodies. Retrospective analysis of the patient's sera showed that IP(3)R3 antibodies were decreasing. Since myocardium is particularly rich in mitochondria, it is thought that myocardial infarction may have been the triggering event that initiated antigen-presenting cells to selectively induce an anti-mitochondrial antibody response.

Demonstration of Autoimmunity in the Tight Skin-2 Mouse: A Model for Scleroderma

The tight skin-2 (Tsk2/+) mouse has been proposed as an animal model of systemic sclerosis (SSc) because this animal exhibits increased collagen synthesis and accumulation in the dermis. The Tsk2/+ mouse also has been reported to have a mononuclear cell infiltrate in the dermis; however, to date no evidence of autoimmunity has been described in this animal model. We report here that Tsk2/+ mice harbor numerous autoantibodies in their plasma including some, which are similar to those, present in SSc patients. Immunofluorescence with HEp-2 cells revealed the presence of anti-nuclear Abs (ANAs) in the plasma of 92% of the Tsk2/+ mice. In contrast, <5% of cage-mated CAST/ei mice had a positive ANA and none of the C3H/HeJ age-matched controls were positive. Homogenous, speckled, rim, nucleolar, centromere as well as combinations of these patterns were observed. The proportion of Tsk2/+ animals with a positive ANA increased slightly with age. ELISAs showed that 93% of the Tsk2/+ animals were positive for anti-Scl70, 82% for anti-centromere, 5% for anti-RNP/Sm, and none were positive for anti-RNA-polymerase II Abs. Indirect immunofluorescence with Crithidia luciliae and ELISA for anti-dsDNA Abs showed that 76% of Tsk2/+ mice were positive for this autoantibody. The high frequency of anti-Scl70 and anti-centromere autoantibodies indicates that Tsk2/+ mice display some humoral immune alterations which are similar to those found in patients with SSc. However, the Tsk2/+ mice also develop autoantibodies to dsDNA and a majority of the mice develop multiple autoantibody specificities (anti-Scl70, anti-CENP-B, and anti-dsDNA) indicating that the mouse may be a useful model to study autoimmunity in a wider spectrum of connective tissue diseases.

Antibodies to centromere antigens measured by an automated enzyme immunoassay

BACKGROUND

Anticentromere antibodies (ACA) are frequently observed in patients with Raynaud's phenomenon and in the CREST syndrome, a subclass of systemic sclerosis. Likewise, ACA are also found in other autoimmune and non-autoimmune diseases. The objective of the present study was to evaluate the clinical utility of the measurement of antibodies to the best characterized centromere antigen (CENP-B) protein by an enzyme-linked immunosorbent assay (ELISA) that uses human recombinant CENP-B antigen and compare it with indirect immunofluorescence assay (IFA) on HEp-2 cells.

METHODS

We have analyzed 128 sera samples from patients with the following diseases: systemic lupus erythematosus (SLE, n = 53), mixed connective tissue disease (n = 1), primary Sjögren syndrome (n = 10), primary Raynaud's phenomenon (n = 10), primary systemic sclerosis (n = 7), polymyositis/dermatomyositis (n = 3), rheumatoid arthritis (n = 9), cutaneous lupus (n = 5), primary biliary cirrhosis (n = 9), chronic autoimmune hepatitis (n = 5) and ANA-positive non-autoimmune diseases (n = 16).

RESULTS

The ELISA evaluated shows a good concordance with IFA, with the advantage of being an automatable quantitative technique.

CONCLUSIONS

Measurement of anticentromere antibodies by this ELISA using human recombinant antigen is a useful alternative for the autoimmune laboratory checking for diseases associated with anticentromere antibodies.

Coexistence of antitopoisomerase I and anticentromere antibodies in patients with systemic sclerosis

BACKGROUND

Antibodies targeting DNA topoisomerase I (ATA) or centromere proteins (ACA) are associated with clinical subsets of patients with systemic sclerosis (SSc). The occurrence of those autoantibodies is considered to be mutually exclusive.

OBJECTIVE

To describe the clinical and immunogenetic data of three patients who are co-expressing both antibodies, and then review previous publications.

METHODS

Both antibodies were detected by different methods, including indirect immunofluorescence technique, enzyme linked immunosorbent assay, immunodiffusion, and immunoblot. Patients were HLA typed by serological and molecular genetic methods. Data were extracted from published reports for comparison. The search for published studies was through Medline and other database research programmes.

RESULTS

During routine laboratory diagnostics over several years three patients with scleroderma and coincidence of ATA and ACA were identified: patient 1 with diffuse SSc, Raynaud's phenomenon, puffy fingers and fingertip necrosis, contractures, and calcinosis; patient 2 with diffuse SSc, Raynaud's phenomenon, oedema of the hands, and interstitial calcinosis of hands, knees, and shoulders, and pulmonary fibrosis; patient 3 with scleroderma of hands, forearms, and face, Raynaud's phenomenon, puffy fingers, finger contractures, fingertip necrosis, and calcinosis. All three patients studied were carriers of HLA alleles known to be associated with these autoantibodies. In serial measurements the concentrations of the two antibodies showed independent or even reverse fluctuations. Screening of 100 patients with ACA for ATA and vice versa disclosed no further patients with coincidence of these antibodies. Twenty eight cases of ACA/ATA coexistence in 5423 patients (0.52%) with SSc or SSc associated symptoms were found in an analysis of published studies.

CONCLUSION

The expression of ATA and ACA is not totally mutually exclusive, but coincidence is rare (<1% of patients with SSc). Patients with both autoantibodies often have diffuse scleroderma and show immunogenetic features of both antibody defined subsets of SSc.

Autoantibodies Associated with Rheumatic Diseases

The identification of circulating autoantibodies contributes to the correct diagnosis as well as to the follow-up of rheumatic diseases. Some autoantibodies are even included in diagnostic and classification criteria for these types of autoimmune diseases. There are several relatively specific screening and identification methods for the measurement of autoantibodies available. The type of assay crucially influences the diagnostic value of the parameters. In general, routine laboratories should prefer enzyme immunoassays (ELISA) using well characterized antigens, although ELISA tests tend to produce more false-positive and true weakly positive results, which reduce their positive predictive value. Therefore one should be aware that laboratory results can only be properly interpreted when there is a correlation with the clinical situation and when the limitations of the technologies used for autoantibody identification have been taken into consideration. A diagnostic algorithm consisting of screening and identification steps should be established by each laboratory in order to create a rational, evidence-based and cost-effective basis for the diagnosis of rheumatic diseases.

Primary biliary cirrhosis. Is (and how much of) the pathology preventible?

Primary biliary cirrhosis (PBC) is a chronic, progressive cholestatic liver disease, which is invariably fatal. Circumstantial and indirect evidence suggests that autoimmune mechanisms have a role in the pathogenesis of PBC. Antimitochondrial antibodies (AMA) are highly sensitive and specific markers that can predict the development of the disease in a healthy individual. Long-term administration of ursodeoxycholic acid (UDCA), a naturally occurring bile acid, safely slows the progression of PBC, delays the need for liver transplantation, and postpones death. An effort should be made to identify the patients with PBC in the asymptomatic stage by the presence of AMA and to conduct a clinical trial in order to assess the benefit of long-term administration of UDCA on the prevention of the overt disease in these individuals.

Antibodies to P450IID6, SLA, PDH-E2 and BCKD-E2 in Japanese patients with chronic hepatitis

Auto-antibodies specific to various antigens in chronic hepatitis (CH) have been detected but their specificities and implications were uncertain. The aims of the present study were to investigate the frequency and the significance of seropositivity of antibodies to P450IID6 or liver/kidney microsome 1 (LKM1), soluble liver antigen (SLA), pyruvate dehydrogenase (PDH) and branched-chain keto acid dehydrogenase (BCKD) in 188 Japanese patients with different forms of CH by western blot or enzyme immunoassay (EIA). Anti-LKM1 was also measured by indirect immunofluorescent test. Anti-P450IID6 was found in 6/188 (3.2%) CH patients including 5/104 (4.8%) with hepatitis C virus (C) infection and 1/12 (8.3%) CH-C patients with antibodies to nuclear and smooth muscle antigens and hypergammaglobulinaemia (> 2.5 g/dL). This patient was the only one diagnosed with autoimmune hepatitis (AIH). All CH patients with hepatitis B (B), hepatitis non-B non-C (NBNC) and AIH were seronegative for anti-LKM1. Antibodies to soluble liver antigen were found in two of 188 (1%) patients, one with AIH and one with CH-B. Anti-BCKD-E2 but not anti-PDH-E2 was found in four patients (2.5%), one with AIH, two with CH-C, and one with NBNC. There was no obvious difference in age, sex ratio and laboratory findings in patients with or without anti-SLA and anti-BCKD-E2. Antibodies to P450IID6, SLA, PDH-E2 and BCKD-E2 are uncommon in adult CH-C, CH-B, CH-NBNC and AIH patients in Japan. Some of these patients positive for auto-antibodies appear to have autoimmune features and might require a careful follow up. The heterogeneity of these antibodies in CH preclude further justification for subtyping of AIH by the presence of the distinct auto-antibodies.