Overcoming a “Probable” Diagnosis in Antimitochondrial Antibody Negative Primary Biliary Cirrhosis: Study of 100 Sera and Review of the Literature

Primary Biliary Cholangitis: Epidemiology, Diagnosis, and Presentation

Using ursodeoxycholic acid as a standard treatment and for its ability to test for antimitochondrial antibody to accelerate diagnosis, survival of primary biliary cholangitis patients has approached that of the general population, leading to a change in nomenclature from primary biliary cirrhosis to primary biliary cholangitis to more accurately describe the disease.

FcγRIIB expression increases during primary biliary cholangitis

Primary biliary cholangitis (PBC) is a severe disease with unknown aetiology and poor prognosis owing to ineffective treatment. B-cell antibodies play a regulatory role during immune responses; therefore, their role in PBC should not be overlooked. Fcγ receptors (FcγRs) of IgG and cell surface glycoproteins play an important role in autoimmune and infectious disease prevention. In this study, 60 patients with PBC and 35 healthy controls (HCs) were recruited. The number of B cells and the expression of the FcγRIIB on the peripheral blood mononuclear cells of patients with PBC were evaluated using FACS. The concentrations of soluble FcγRs were determined using ELISA, and intrahepatic FcγRIIB and CD19 expressions in patients with PBC were visualised using IHC. FcγRIIB expression in B cells was significantly higher in patients with PBC than in HCs (P < 0.0001). The soluble FcγRIIB levels in the plasma were higher in patients with PBC than in HCs (P = 0.0009). Notably, these levels were reduced by treatment with ursodeoxycholic acid (P = 0.0236). CD19 and FcγRIIB expression increased in the liver of patients with PBC relative to that in HCs. These findings can provide new insights into PBC pathogenesis and can aid the future development of treatment strategies.

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.

Research experimental design for the construction and identification of the pGEX-BCKD-E4A recombinant point-mutant plasmid

Primary biliary cirrhosis (PBC) is an organ-specific autoimmune disease that eventually develops into cirrhosis and even liver cancer. In recent years, the incidence rate has been increasing, and the early diagnosis and treatment of PBC are crucial. In the early diagnosis method of PBC, anti-mitochondrial antibodies (AMAs) are an important diagnostic basis, especially the M2 subtype (AMA-M2) with almost 100% specificity. We selected the BCOADC-E2 protein, a mitochondrial autoantigen that reacts specifically with AMA-M2 antibodies, and carried out DNA recombination and protein mutation experiments by cloning in vitro the homologous target gene sequence BCKD that expresses the antigenic epitope of BCOADC-E2 protein, to provide experience for later exploring the effect of mutations of amino acids around the lysine in the active center of BCOADC-E2 protein on its specific binding to AMA-M2, and to lay the foundation for determining the key amino acids of BCOADC-E2 for the diagnosis and treatment of PBC. In addition, we apply this scientific research content to graduate course teaching. Experimental technology of microbial molecular ecology is a course with the cross-integration of multidisciplinary knowledge and experimental skills offered at our college since 2018. This article derives from the part of this course on the construction of recombinant plasmids. The students first constructed the recombinant plasmid pGEX-BCKD using the vector plasmid pGEX-4T1 and the target gene fragment BCKD provided by the laboratory and used this as a template to construct the pGEX-BCKD-E4A point mutation plasmid by the overlap extension PCR (SOE PCR) technique to achieve the effect of mutating the fifth amino acid glutamate in front of lysine, the active centre of the BCOADC-E2 lipid acyl binding domain, to alanine for subsequent studies. Through the research experiment, combining theoretical knowledge and experimental operation, we aim to deepen the student's understanding of DNA recombination technology, let them feel the practical application prospect of experimental technology, stimulate students' interest in professional knowledge learning, and cultivate students' scientific thinking and innovation consciousness. We examined the quality of the teaching through the process and summative evaluation of the students. In this study, the students successfully completed the construction of pGEX-BCKD-E4A point mutant plasmid, and the average test score increased from 40.4% before teaching to 91.1%. The teaching effect was remarkable. This kind of research experimental teaching mode has good application prospects, and other education and teachers can refer to and reference it.

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.

Autoantibodies in Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic immune-mediated liver disease characterized by a lymphocytic cholangitis, with subsequent cholestasis, progressive liver fibrosis, and ultimately complications arising from end-stage liver disease. Testing for autoantibodies is important in the diagnosis of PBC, as well as stratifying prognosis. This review focuses on the role of autoantibodies in the diagnosis of PBC, as well as the relationship between autoantibodies with pathophysiology and prognostication, along with a discussion regarding novel and other related disease autoantibodies.

Optimization of Laboratory Diagnostics of Primary Biliary Cholangitis: When Solid-Phase Assays and Immunofluorescence Combine

The laboratory diagnostics of primary biliary cholangitis (PBC) have substantially improved, thanks to innovative analytical opportunities, such as enzyme-linked immunosorbent assays (ELISA) and multiple immunodot liver profile tests, based on recombinant or purified antigens. This study aimed to identify the best diagnostic test combination to optimize PBC diagnosis. Between January 2014 and March 2017, 164 PBC patients were recruited at the hospitals of Parma, Modena, Reggio-Emilia, and Piacenza. Antinuclear antibodies (ANA) and anti-mitochondrial antibodies (AMA) were assayed by indirect immunofluorescence (IIF), ELISA, and immunodot assays (PBC Screen, MIT3, M2, gp210, and sp100). AMA-IIF resulted in 89.6% positive cases. Using multiple immunodot liver profiles, AMA-M2 sensitivity was 94.5%, while anti-gp210 and anti-sp100 antibodies were positive in 16.5% and 17.7% of patients, respectively. PBC screening yielded positive results in 94.5% of cases; MIT3, sp100, and gp210 were detected by individual ELISA test in 89.0%, 17.1%, and 18.9% of patients, respectively. The association of PBC screening with IIF-AMA improved the diagnostic sensitivity from 89.6% to 98.2% (p < 0.01). When multiple immunodot liver profile testing was integrated with AMA-IIF, the diagnostic sensitivity increased from 89.1% to 98.8% (p < 0.01). The combination of IIF with solid-phase methods significantly improved diagnostic efficacy in PBC patients.

Detecting Autoantibodies by Multiparametric Assays: Impact on Prevention, Diagnosis, Monitoring, and Personalized Therapy in Autoimmune Diseases

BACKGROUND

The introduction of multiparametric autoantibody tests has been proposed to improve the accuracy of the immunological diagnosis of autoimmune diseases (AID) and to accelerate time for completing the diagnostic process. Multiplex tests are capable of detecting many autoantibodies in a single run whereas a traditional immunoassay uses a single antigen to detect only a single specificity of autoantibodies. The reasons why multiplex tests could replace conventional immunoassays lie in the evidence that they allow for more efficient handling of large numbers of samples by the laboratory, while ensuring greater diagnostic sensitivity in AID screening.

CONTENT

This review aims to highlight the important role that multiparametric tests could assume when designed for defined profiles they are used not only for diagnostic purposes but also to predict the onset of AID to identify clinical phenotypes and to define prognosis. Furthermore, differences in the antibody profile could identify which subjects will be responsive or not to a specific pharmacological treatment.

SUMMARY

The use of autoantibody profiles, when specifically requested and performed with clinically validated technologies, can represent a significant step toward personalized medicine in autoimmunology.

Antimitochondrial Antibodies: from Bench to Bedside

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

Antinuclear antibodies (ANA) as a criterion for classification and diagnosis of systemic autoimmune diseases

The classification and diagnosis of systemic autoimmune diseases are frequently based on a collection of criteria composed of clinical, laboratory, imaging, and pathology elements that are strongly associated with the respective disease. Autoantibodies are a distinctive hallmark and have a prominent position in the classification criteria of many autoimmune diseases. The indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA), historically known as the antinuclear antibody test, is a method capable of detecting a wide spectrum of autoantibodies. A positive HEp-2 IFA test is part of the classification criteria for systemic lupus erythematosus (SLE) and juvenile idiopathic arthritis (JIA), as well as the diagnostic criteria for autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC). A positive HEp-2 IFA test can appear as different morphological patterns that are indicative of the most probable autoantibody specificities in the sample. Only some of the HEp-2 IFA patterns are associated with the specific autoantibodies relevant to SLE, JIA, AIH, and PBC, whereas some other patterns occur mainly in non-related conditions and even in apparently healthy individuals. This paper provides a critical review on the subject and proposes that the classification and diagnostic criteria for SLE, JIA, AIH, and PBC could be improved by a modification on the HEp-2 IFA (ANA) criterion in that the staining patterns accepted for each of these diseases should be restricted according to the respective relevant autoantibody specificities.

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Autoantibodies play a prominent role in the classification or diagnostic criteria of many autoimmune diseases.

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ANA test is part of the classification criteria for SLE and JIA, as well as the diagnostic criteria for AIH.

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Different HEp-2 IFA patterns indicate different autoantibodies and only some are associated with a specific disease.

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ANA classification/diagnostic criteria should reflect the HEp-2 IFA patterns associated to the relevant autoantibodies.

Clinical impact of antibodies to Sp100 on a bacterial infection in patients with primary biliary cholangitis

BACKGROUND

A specific antinuclear antibody for primary biliary cholangitis (PBC) is anti-Sp100, which was recognized as a serological marker of concurrent urinary tract infection. We sought to determine the clinical characteristics of PBC patients who had anti-Sp100.

PATIENTS AND METHODS

Fifty-one patients with PBC and 10 healthy controls (HCs) were enrolled. Anti-Sp100 were determined with an ELISA method. Lipopolysaccharide-binding protein (LBP) was measured as a serological hallmark for bacterial infection. The correlations of anti-Sp100 with demographic, laboratory, and pathological parameters were investigated.

RESULTS

Six of the 51 (11.8%) PBC patients had anti-Sp100, whereas none of the HCs did. There was no significant difference in the frequency of antimitochondrial antibodies (AMAs) between PBC patients with and without anti-Sp100 (67% vs. 82%, p = 0.5839). Biochemical and immunological parameters were not associated with the emergence of anti-Sp100 in these patients. The clinical stage by Scheuer classification was not correlated with the existence of anti-Sp100. No significant difference in the serum LBP levels was found between PBC patients with and without anti-Sp-100, although serum LBP levels were significantly higher in PBC patients with anti-Sp100 than in HCs (8.30 ± 2.24 ng/ml, vs. 5.12 ± 2.48 ng/ml, p = 0.0022). The frequency of granuloma formation was higher in the liver specimens of PBC patients with anti-Sp100 than in those without anti-Sp100 (67% vs 29%, p = 0.0710).

CONCLUSION

anti-Sp100 does not become a complementary serological marker for PBC in AMA-negative patients. A bacterial infection may trigger the production of anti-Sp100. Another factor is required to initiate the autoantibody production.

Detection of anti-kelch-like 12 and anti-hexokinase 1 antibodies in primary biliary cholangitis patients in China

OBJECTIVES

primary biliary cholangitis (PBC) is a chronic cholestatic disease, characterized by positive anti-mitochondrial autoantibodies (AMA) in 90-95 % patients. Anti-kelch-like 12 (anti-KLHL12) and anti-hexokinase1 (anti-HK1) antibodies have been identified as the two new serum markers in recent years, which are used in the diagnosis of AMA-negative PBC patients. The objective of the study was to examine the performance of these two new biomarkers in China.

METHODS

a total of 192 patients were enrolled and screened for anti-KLHL12 and anti-HK1 antibodies and AMA by ELISA. Receiver operating characteristic (ROC curve) analysis was applied to examine the diagnostic importance of AMA, anti-KLHL12 and anti-HK1 antibodies. Furthermore, correlation analysis between some important biochemical indexes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase [ALP], bilirubin, gamma-glutamil transferasa [γ-GT]), staging of pathological changes of the liver and the expression of novel antibodies in PBC patients were also examined.

RESULTS

the positivity of the anti-HK1 antibody in AMA-positive PBC patients and AMA-negative patients was 44.7 % and 33.3 %, respectively. The specificity, proportion of positive patients (PPV) and proportion of negative patients (NPV) were 93 %, 89 % and 53 %, respectively. In contrast, the positivity to the anti-KLHL12 antibody in AMA-positive and negative PBC patients was 41.2 % and 22.2 %, respectively. Specificity, PPV and NPV were 98 %, 95 % and 52 %, respectively. The area under the curve (AUC) with anti-HK1 and anti-KLHL12 antibodies were 0.720 and 0.703. With the combination with anti-HK1 and anti-KLHL12 antibodies, the AUC of AMA increased from 0.889 to 0.891, increasing the sensitivity from 0.764 to 0.836. Anti-KLHL12 and anti-HK1-positive patients had higher serum levels of ALP, γ-GT and bilirubin, with statistically significant differences (p < 0.01) compared with anti-KLHL12 or anti-HK1-negative patients. Notably, correlation analysis showed a significant positive correlation between antibody expression and ALP, γ-GT and bilirubin serum levels (r = 0.735, 0.491, 0.466; p < 0.01).

CONCLUSIONS

anti-HK1 and anti-KLHL12 antibodies have been identified as two significant biomarkers in PBC patients. Furthermore, the presence of these antibodies is likely to correlate with the severity of PBC.

Analysis of Autoantibodies against Promyelocytic Leukemia Nuclear Body Components and Biochemical Parameters in Sera of Patients with Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease characterized by immune-mediated destruction of intrahepatic bile ducts and the presence of specific antibodies. The aim of the study was to examine the diagnostic significance of antibodies against promyelocytic leukemia nuclear body (PML NB) components such as Sp100, Sp140, and PML in a cohort of PBC patients and compare the results with biochemical and histological parameters. Serum samples were collected from 93 PBC patients. Anti-Sp100 and anti-PML antibodies were assessed using commercially available kits, anti-Sp140 using developed “in-house” ELISA test. Anti-Sp140, anti-Sp100, and anti-PML antibodies were present in 25 (27%), 37 (40%), and 29 (31%) PBC patients, respectively. Anti-PML NB positive patients also showed increased concentration of bilirubin and alkaline phosphatase (p < 0.05). In the group with the presence of at least two types of these antibodies, more frequent deaths or transplantations were observed. A correlation between the presence of antibodies and histological grade (OR = 2.55 p = 0.039) was established. Patients with bilirubin > 1.1 mg/dL at the time of diagnosis had a significantly shorter time of survival than patients with bilirubin ≤ 1.1 mg/dL (HR 5.7; 95% C.I., 2.7, 12.3; p < 0.001). Our data confirm very high specificity of anti-PML NB antibodies, which can expand the laboratory diagnostic capabilities of PBC. We found an association between positive reactivity of autoantibodies directed against components of PML nuclear bodies and higher concentrations of bilirubin and alkaline phosphatase, but the main prognostic marker of survival remains serum bilirubin.

Clinical significance of IgG antimitochondrial M2 antibody levels in primary biliary cholangitis: A single center study from China

Background and objective

The relationship between antimitochondrial antibody (AMA) levels and the severity or prognosis of primary biliary cholangitis (PBC) is unclear. This study explored the clinical significance of serum IgG antimitochondrial M2 antibody (IgG-M2) levels.

Methods

From 2008 to 2017, a retrospective analysis was conducted with PBC patients who had available quantitative values of serum IgG-M2 levels obtained with ELISA based on triple expression hybrid clones. The patients were divided into two groups based on high and low concentrations of IgG-M2. Baseline parameters, the incidence of adverse events, and prognosis were compared.

Results

Among the 530 PBC patients, the levels of albumin, cholinesterase, hemoglobin, fibrinogen and triglycerides and the red blood cell count were significantly lower in the high-concentration group than in the low-concentration group (n = 263, 49.6%). The red cell distribution width (RDW) and levels of serum immunoglobulin (Ig) G, IgM and IgA were significantly higher in the high-concentration group than in the low-concentration group. Spearman’s correlation analysis suggested that the correlation between the above baseline indicators and IgG-M2 levels was statistically significant but weak (r < 0.2, P < 0.05). In total, 203 patients were followed up, of whom 87 (42.9%) were in the high-concentration group. During the median follow-up period of 52 months (range: 28–75), 121 (59.6%) experienced hepatic decompensation, and 37 (18.2%) died or underwent liver transplantation. There was no significant difference in the incidence of complications or survival (log-rank test: P = 0.079) between the two groups. One year after ursodeoxycholic acid (UDCA) treatment, the two groups had similar responses. In addition, the levels of IgG-M2 did not fluctuate significantly during treatment.

Conclusion

IgG-M2 levels were not related to the disease severity, prognosis or efficacy of UDCA. The levels of IgG-M2 did not change significantly during treatment.

Evaluation of a novel extended automated particle-based multi-analyte assay for the detection of autoantibodies in the diagnosis of primary biliary cholangitis

Background

Anti-mitochondrial autoantibodies (AMA) detected by indirect immunofluorescence (IIF) on rodent tissues are the diagnostic marker of primary biliary cholangitis (PBC). However, up to 15% of patients with PBC are AMA-negative by IIF. In the effort to close the serological gap and improve the diagnostic sensitivity of PBC testing, recently, novel autoantibodies specific for PBC, such as kelch-like 12 (KLHL12, KLp epitope) and hexokinase 1 (HK1) have been described. In this study, we evaluated the autoantibody profile in a large cohort of PBC patients and in patients with other liver disease, including anti-HK1 and anti-KLp autoantibodies.

Methods

Sera of 194 PBC patients (126 AMA-IIF-positive and 68 AMA-IIF-negative) and 138 disease controls were tested for a panel of PBC-specific antibodies (MIT3, sp100, gp210, HK1, KLp) using a new automated particle-based multi-analyte technology (PMAT) assay on the Aptiva instrument (Inova).

Results

Selecting a cutoff yielding a specificity of >95% for all the markers, the sensitivity for anti-MIT3, anti-sp100, anti-gp210, anti-HK1 and anti-KLp in the PBC AMA-IIF-negative cohort was 20.6%, 16.2%, 23.5%, 22.0%, 17.6 and 13.2%, respectively. Six out of the 68 (8.8%) AMA-IIF negative sera were positive for anti-HK1 or anti-KLp alone. Using these new markers in addition to anti-MIT3, anti-sp100 and anti-gp210, the overall sensitivity in this cohort of AMA-IIF-negative patients increased from 53% to 61.8%, reducing the serological gap in AMA-negative PBC patients.

Conclusions

PBC antibody profiling, made possible by the new Aptiva-PMAT technology, allows recognition of a higher number of AMA-negative PBC patients than conventional immunoassays and may represent a useful tool to evaluate the prognostic significance of autoantibody association in PBC patients.

Investigation and analysis of HEp 2 indirect immunofluorescence titers and patterns in various liver diseases

INTRODUCTION

Antinuclear antibody (ANA) testing using indirect immunofluorescence assay (IIFA) is a common and economical method which contributes to detect systemic autoimmune diseases (SARD) and autoimmune liver diseases (AILD). The primary aim of our study was to investigate ANA positivity and their patterns in multiple liver diseases, including primary biliary cirrhosis (PBC), autoimmune hepatitis (AIH), hepatitis B virus infection (HBV), hepatitis C virus infection (HCV), and hepatic carcinoma (HCC). Besides, we also compared the ANA titers and patterns in patients with liver disease, SARD, and healthy controls (HC).

METHODS

A total of 2537 patients with SARD, 137 PBC cases, 57 AIH cases, 3420 HBV cases, 769 HCV cases, 268 HCC cases, and 1073 HC were retrospectively assessed. The titers and patterns of ANA were detected with the IIFA method.

RESULTS

ANA positivity rate was considerably discernible between these diseases, which is 90.1% in SARD, 93.4% in PBC, 49.1% in AIH, 19.1% in HBV, 13.9% in HCV, and 23.5% in HCC. Moreover, only 4.9% of HCC cases, 2.5% of HBV patients, and 1.6% of HCV patients had an ANA titer ≥ 1:320. The mixed pattern which composed of at least two patterns majorly lied in PBC. AC-15 and AC-21 was frequently related to liver diseases; the former pattern was more frequently found in AIH (84.2%) and PBC (8.8%), and the latter pattern was easily seen in PBC (62.2%) and HCC (22.6%). The positive rate of ANA in HC was 12.2%, and its major pattern was AC-2.

CONCLUSIONS

There are differences in ANA positivity among patients with SARD and various liver diseases. Some mixed patterns may provide important evidence for the diagnosis of PBC. Clinicians should pay attention to ANA patterns and titer during the interpretation of this test. Key Points • Defining the clinical relevance of antinuclear antibody (ANA) using indirect immunofluorescence assay in the context of diseases can be an important tool for the clinician in the diagnostic work-up of patients with liver diseases. • The mixed pattern of ANA is majorly found in primary biliary cirrhosis (PBC). ANA patterns including AC-15 and AC-21 are frequently related to liver diseases. AC-15 is more often found in autoimmune hepatitis (AIH) (84.2%) and PBC (8.8%), and AC-21 is easily found in PBC (62.2%, and hepatic carcinoma (HCC) (22.6%). • ANA positivity can be seen in 19.1% of hepatitis B virus infection (HBV) cases, 13.9% of hepatitis C virus infection (HCV) cases, and 23.5% of HCC cases. Only 2.5% of HBV patients, 1.6% of HCV patients, and 4.9% of HCC cases have an ANA titer ≥ 1:320.

Fluctuations of antimitochondrial antibodies and anti-gp210 antibody in a patient with primary biliary cholangitis and Sjögren syndrome with subsequent autoimmune hemolytic anemia: A case report

RATIONALE

Primary biliary cholangitis (PBC) is a rare autoimmune cholestatic liver disease. It is often associated with extrahepatic autoimmune disorders. However, the concurrence of PBC and Sjögren syndrome (SS) with the subsequent onset of autoimmune hemolytic anemia (AIHA) is extremely rare.

PATIENT CONCERNS

This study investigated a 60-year-old woman admitted to our hospital with complaints of xerostomia for 5 years, pruritus for 3 years, and abnormal liver function for 3 months.

DIAGNOSES

The patient was suffering from typical clinical PBC and SS, and developed decompensated liver cirrhosis after 32 months of ursodeoxycholic acid (UDCA) therapy. In May 2018, she was readmitted to the hospital with a high fever of 39 °C, coughing, and sever fatigue without remission after 3 days of cephalosporin antibiotic therapy. During the clinical course of PBC, her antimitochondrial antibodies (AMA) titers fluctuated from 1:1000 to negative and then to weakly positive, determined by indirect immunofluorescence (IIF), immunoblotting, and enzyme-linked immunosorbent assay (ELISA) based on recombinant mitochondrial antigens; furthermore, her titers of anti-gp210, an antinuclear antibody (ANA), increased sharply. Laboratory tests and imaging were performed to diagnose PBC and SS in September 2015. However, she was subsequently diagnosed with AIHA after 32 months of UDCA therapy based on the identification of pancytopenia, increased reticulocyte (RET) count, and a positive result from the direct Coombs test.

INTERVENTIONS

UDCA, hepatic protectant, albumin infusion, chest drainage, rational antibiotic use, diuretics, and methylprednisolone were used to treat the patient.

OUTCOMES

Liver cirrhosis was complicated by the development of AIHA, which became severe at 42 months of follow-up.

LESSONS

This is the first case report showing a patient with comorbid PBC and SS, as well as the sequential development of AIHA with decreased AMA and increased anti-gp210 titers; this may have been due to immunodeficiency. These findings stress the importance of the serological screening of ANA profile, as well as repeated measurement of ANA and AMA to track PBC progression and prognosis.

Meta-Analysis of Antinuclear Antibodies in the Diagnosis of Antimitochondrial Antibody-Negative Primary Biliary Cholangitis

Objective

The diagnostic value of antinuclear antibodies (ANAs) including anti-gp210 and anti-sp100 for primary biliary cholangitis/cirrhosis (PBC) has been widely reported. However, their diagnostic performances for antimitochondrial antibody- (AMA-) negative PBC were less well elucidated. Therefore, the aim of the current meta-analysis was to evaluate the diagnostic accuracy of ANAs in patients with AMA-negative PBC.

Materials and Methods

Literature on the diagnostic value of biomarkers for AMA-negative PBC was systematically searched in PubMed, MEDLINE, EMBASE, and the Cochrane Library. The qualities of the retrieved studies were assessed by the Quality Assessment of Diagnostic Accuracy Studies-version 2 (QUADAS-2) scale. Pooled sensitivity and specificity of the biomarkers were calculated with random-effects models. The areas under the summary receiver operating characteristic (AUSROC) curves were used to evaluate the overall diagnostic performance of ANAs.

Results

A total of 11 studies (400 AMA-negative PBC patients and 6217 controls) were finally included in the meta-analysis. ANAs had an overall sensitivity of 27% (95% CI: 20%, 35%) and specificity of 98% (95% CI: 97%, 99%). The pooled sensitivities for anti-gp210 and anti-sp100 were 23% (95% CI: 13%, 37%) and 25% (95% CI: 13%, 43%), respectively, and their specificities were 99% (95% CI: 97%, 100%) and 97% (95% CI: 93%, 98%), respectively.

Conclusions

ANAs exhibited high specificity but low sensitivity and therefore could be used as reliable biomarkers to reduce the necessity of liver histology.

Variant and Specific Forms of Autoimmune Cholestatic Liver Diseases

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

The British Society of Gastroenterology/UK-PBC primary biliary cholangitis treatment and management guidelines

Primary biliary cholangitis (formerly known as primary biliary cirrhosis, PBC) is an autoimmune liver disease in which a cycle of immune mediated biliary epithelial cell injury, cholestasis and progressive fibrosis can culminate over time in an end-stage biliary cirrhosis. Both genetic and environmental influences are presumed relevant to disease initiation. PBC is most prevalent in women and those over the age of 50, but a spectrum of disease is recognised in adult patients globally; male sex, younger age at onset (<45) and advanced disease at presentation are baseline predictors of poorer outcome. As the disease is increasingly diagnosed through the combination of cholestatic serum liver tests and the presence of antimitochondrial antibodies, most presenting patients are not cirrhotic and the term cholangitis is more accurate. Disease course is frequently accompanied by symptoms that can be burdensome for patients, and management of patients with PBC must address, in a life-long manner, both disease progression and symptom burden. Licensed therapies include ursodeoxycholic acid (UDCA) and obeticholic acid (OCA), alongside experimental new and re-purposed agents. Disease management focuses on initiation of UDCA for all patients and risk stratification based on baseline and on-treatment factors, including in particular the response to treatment. Those intolerant of treatment with UDCA or those with high-risk disease as evidenced by UDCA treatment failure (frequently reflected in trial and clinical practice as an alkaline phosphatase >1.67 × upper limit of normal and/or elevated bilirubin) should be considered for second-line therapy, of which OCA is the only currently licensed National Institute for Health and Care Excellence recommended agent. Follow-up of patients is life-long and must address treatment of the disease and management of associated symptoms.

Antimitochondrial Antibody-Negative Primary Biliary Cholangitis: Is It Really the Same Disease?

Antimitochondrial antibody (AMA)-negative primary biliary cholangitis (PBC) is a term reserved for patients with clinical and histopathological findings consistent with PBC but without positive AMA. There does not seem to be a natural progression from AMA negativity to positivity. Antinuclear and antismooth muscle antibodies are frequently found in the absence of histologic autoimmune hepatitis features. The disease course may be more severe than AMA-positive. Response to standard therapy for PBC and autoimmune hepatitis varies. Nevertheless, there is insufficient evidence to suggest AMA-negative PBC is different enough to warrant classification as a separate disease from AMA-positive PBC.

Biomarkers for primary biliary cholangitis: current perspectives

Primary biliary cholangitis (PBC) is a chronic progressive cholestatic disease characterized by destruction of small- and medium-sized intrahepatic bile ducts. It is no longer a rare disease, since many new asymptomatic cases are incidentally identified. Liver biopsy is diagnostically critical but not always feasible or practical to be performed. Many potential, noninvasive, markers have been proposed to replace liver biopsy and further provide the assessment of disease severity and ultimate prognosis. In this review, we evaluated serum biomarkers proposed for diagnosis, extent of fibrosis, disease prognosis and attempts for early prediction of treatment response. Older biochemical and immunological markers are presented along with recent reports including the role of microRNAs and promising results based on proteomics and metabolomics.

Diagnostic accuracy of two tests for determination of anti-m2 in the diagnosis of primary biliary cirrhosis: Is it possible to predict the course of the disease?

To evaluate the analytical agreement between results obtained from the indirect immunofluorescence methods and from the multiplexed line-blot assay and EliA-M2, to analyze the diagnostic accuracy in a cohort of primary biliary cirrhosis (PBC) patients and in control patients of two different types of tests for anti-M2 and assess whether, with the advent of a quantitative test, the possibility exists to correlate disease activity with the value of AMA. Serum analysis of 67 patients with fluorescence patterns detected on Hep-2 cells suggestive of PBC-related antibodies and three groups of patients (15 PBC, 16 PBC suspect and 48 disease controls) was carried out. All samples were tested by both a qualitative test multiplexed line-blot Autoimmune Liver Disease Profile Euroline and by a quantitative test EliA-M2 IgG. In order to evaluate a possible correlation between the quantitative M2 and disease activity, we divided patients mixed in a further three groups based on the value EliA-M2. For each of these groups were calculated the average values of the main indices of cholestasis. A perfect agreement was shown between the EliA-M2 and the multiplexed line-blot method for AMA detection. All sera of patients with PBC were positive with both tests, with a 100 % sensitivity. Forty-seven of the 48 sera of the control group were negative for both tests with a 100 % next specificity, and only 70 % for the AMA-IIF. We had also observed in the other three groups of patients that the average of the values of γ-glutamyl transpeptidase and alkaline phosphatase increases with the increase of the value EliA-M2. The difference between the mean values of the most significant parameter which the alkaline phosphatase of the three groups is significant, with a statistically significant difference between the first and the third group (p value 0.023). Both the qualitative method Profile Euroline and the quantitative EliA-M2 have a high diagnostic accuracy for PBC, with a specificity higher than the immunofluorescence method. These preliminary data might suggest the possibility of using the dosage EliA-M2 not only in the diagnosis phase but also in the monitoring of disease activity.

The diagnostic accuracy of biomarkers for diagnosis of primary biliary cholangitis (PBC) in anti-mitochondrial antibody (AMA)-negative PBC patients: a review of literature

Primary biliary cholangitis (PBC), also known as primary biliary cirrhosis, is an autoimmune disease of the liver characterized by anti-mitochondrial antibodies (AMA) in 90%-95% of patients. The aim of this study was to evaluate the diagnostic value of several serum biomarkers in patients with PBC but negative for AMA. Some antinuclear antibodies (ANA) pattern, detected by indirect immunofluorescence (IIF), such as multiple nuclear dot (MND) and rim-like patterns are well-known to be specific for PBC. The corresponding nuclear antigens are the components of the nuclear pore complex (Gp210 for rim-like pattern) and Sp100, PML proteins (for MND pattern) detectable by immunoblotting and ELISA methods. More recently, new biomarkers have been evaluated in order to improve the diagnostic sensitivity, such as kelch-like 12 (KLHL12) and hexokinase-1. Considering these different serum biomarkers, studies evaluating their diagnostic role in AMA-negative PBC patients compared to AMA-positive ones and controls were included in this review. Pooled sensitivity and specificity were 37% and 85%, respectively. The overall PPV and NPV mean values were 45% and 83%. Even if all biomarkers are very specific for PBC, the overall sensitivity was poor and therefore is necessary to identify a marker with a greater sensitivity for PBC in AMA-negative patients.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Diagnosis and Treatment of Autoimmune Liver Diseases in a Tertiary Referral Center in Cuba

Background

Autoimmune liver diseases (AILD) comprise a set of entities characterized by tissue damage as a result of the loss of self-tolerance. There are few reports of AILD from Caribbean countries.

Objectives

The aim of our study was to investigate the clinical patterns, laboratory findings, and immunologic features, treatment responses, and prognoses of AILD in adult patients at a Cuban tertiary referral center.

Methods

A prospective study was conducted at the National Institute of Gastroenterology in Havana, Cuba, from May 2012 to April 2016. Clinical, immunologic, and histologic features of autoimmune hepatitis (AIH), primary biliary cirrhosis, AIH/primary biliary cirrhosis overlap syndrome, autoimmune cholangiopathy, and primary sclerosing cholangitis were recorded. Response to therapy was assessed by serum alanine aminotransferase and bilirubin levels at 3, 6, 12, and 24 months after treatment initiation.

Results

Of the 106 patients included in the study, 85.5% were women. The median age at presentation was 47 years. AIH was the most common AILD and was diagnosed in 60 patients (56.6%), 55 of whom had type 1 AIH. Primary biliary cirrhosis was diagnosed in 22 patients (20.7%), overlap syndrome in 16 patients (15%), autoimmune cholangiopathy in 5 patients (4.71%), and PSC in 3 patients (2.8%). Most patients were symptomatic; 48 patients (45.2%) presented with liver cirrhosis, 14.5% of whom had decompensated cirrhosis. Follow-up of treatment was between 6 and 24 months. Prednisone monotherapy was used in 22 AIH patients (36.6%) and a combination of prednisone and azathioprine was used in 28 (46.6%) AIH patients. Response to treatment was seen in 41 AIH patients (68.3%), 33 of whom (55%) had a complete response and 8 of whom (24.2%) relapsed after 12 months of maintenance therapy. No or incomplete response to treatment was seen in 18 patients (30%). In 46 patients with autoimmune cholestasis, ursodeoxycholic acid was used as monotherapy in 25 patients (54.3%).

Conclusions

The clinical profile of AILD in a sample of the Cuban population is similar to that reported in South areas (Developing countries). AIH was more frequent than PBC, and usually presented with advanced liver disease that responded poorly to treatment.

Clinical relevance of combined anti-mitochondrial M2 detection assays for primary biliary cirrhosis

BACKGROUND

Antimitochondrial antibody (AMA) is a specific serologic marker in primary biliary cirrhosis (PBC). The aim of this study was to evaluate the clinical relevance of combined AMA assays.

METHODS

Sera were obtained from 79 patients with PBC and 108 patients with other liver disease. They were tested by indirect immunofluorescence (IIF) using rat kidney/stomach tissue and HEp2 cells as substrate, 4 AMA-M2 assays, anti-sp100, and anti-gp210 assays.

RESULTS

Using IIF-AMA with cut-off titer of 1:40, the sensitivity and specificity for PBC were 88.6% and 87.0%, respectively. A cut-off titer of 1:80 improved the specificity to 93.5%. The 4 commercial assay kits using AMA-M2 autoantibodies showed sensitivity of 55.7-79.7% and specificity of 91.7-95.4% with moderate to good agreement. AMA-M2 assays using both native and recombinant E2 antigens had higher sensitivity. ANAs on HEp2 cells, anti-sp100, and anti-gp210 were detected in 67.1%, 13.9-15.2%, and 22.8-27.8% of PBC patients, respectively. Additional AMA-M2 specific assays in IIF-AMA negative and low titer positive (1:40) sera increased the sensitivity and specificity to 88.6% and 90.7%, respectively.

CONCLUSIONS

Serological diagnosis for PBC using IIF with high titer cut-off and additional AMA-M2 specific tests by ELISA or LIA in IIF-negative sera should be used.

The diagnosis of antimitochondrial antibody-negative primary biliary cholangitis

Autoimmune liver diseases are heterogenous disorders that share largely non-specific clinical, serological and pathological features. The correct diagnosis requires discriminative features which are highly specific, for example high-titer antimitochondrial antibodies (AMA) and florid duct lesion in primary biliary cholangitis (PBC). However, the imperfect sensitivities of these characteristic features and abuse of scoring systems led to many artificial diagnoses such as overlap syndromes and outliers for example "autoimmune cholangitis" which is now called as "AMA-negative PBC". Patients lacking detectable AMA (up to 20% in indirect immunofluorescence - IF), but otherwise presenting signs and symptoms of PBC should be regarded as affected by "AMA-negative PBC" because they seem to follow a natural history similar to that of their AMA positive counterparts. The complementary use of IF, ELISA and immunoblotting have disclosed that the majority of patients initially considered AMA-negative are in fact AMA positive. Moreover, the use of PBC-specific ANA's like Gp210 and sp100 have diminished the AMA-negative cases (if truly exists!) to less than 5%. The histological spectrum of PBC includes typical florid duct lesions and/or compatible features such as non-specific hepatitic and biliary findings. In the absence of florid duct lesion and AMA positivity, histology alone cannot differentiate PBC from other biliary disorders. However, the analysis of compatible histological features with the clinical, serological and imaging findings usually points to a specific diagnosis. In this review, we present serological, clinical and pathological pitfalls regarding AMA-negative PBC including illustrative cases and a diagnostic algorithm.

A contemporary perspective on the molecular characteristics of mitochondrial autoantigens and diagnosis in primary biliary cholangitis

Primary biliary cholangitis (PBC) is an autoimmune hepatobiliary disease characterized by immune mediated destruction of the intrahepatic small bile ducts and the presence of antimitochondrial antibodies (AMAs). The mitochondrial autoantigens have been identified as the E2 subunits of the 2-oxo-acid dehydrogenase complex, including the E2 subunits of pyruvate dehydrogenase, branched-chain 2-oxo acid dehydrogenase complex, oxoglutarate dehydrogenase complex, E3 binding protein and PDC E1 alpha subunit. The AMA epitope is mapped within the E2 lipoic acid binding domain, which is particularly important for oxidative phosphorylation. In addition, lipoic acid, which serves as a swinging arm to capture electrons, is particularly susceptible to an electrophilic attack and may provide clues to the etiology of PBC. This review emphasizes the molecular characteristics of AMAs, including detection, immunochemistry and the putative role in disease. These data have significance not only specifically for PBC, but generically for autoimmunity.

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.

Advances in understanding pathogenesis of primary biliary cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterized by chronic and progressive cholestasis. In recent years, the incidence and prevalence of PBC are increasing year by year. However, the etiology and pathogenesis are not fully understood. It is believed that genetic susceptibility, environmental factors, and immunologic tolerance are related with the pathogenesis of PBC. This article reviews the progress in the understanding of the pathogenesis of PBC.

Primary biliary cirrhosis: Clinical and laboratory criteria for its diagnosis

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic granulomatous, and destructive inflammatory lesion of small intralobular and septal bile ducts, which is likely to be caused by an autoimmune mechanism with a the presence of serum antimitochondrial antibodies and a potential tendency to progress to cirrhosis. Despite the fact that the etiology of this disease has been unknown so far, there has been a considerable body of scientific evidence that can reveal the clinical and laboratory signs of PBC and the individual components of its pathogenesis and elaborate diagnostic criteria for the disease and its symptomatic therapy. Deficiencies in autoimmune tolerance are critical factors for the initiation and perpetuation of the disease. The purpose of this review is to summarize the data available in the literature and the author’s findings on clinical and laboratory criteria for the diagnosis of PBC. This review describes the major clinical manifestations of the disease and the mechanisms of its development. It presents the immunological, biochemical, and morphological signs of PBC and their significance for its diagnosis. A great deal of novel scientific evidence for the problem of PBC has been accumulated. However, the inadequate efficiency of therapy for the disease lends impetus to the quest for its etiological factors and to further investigations of its pathogenetic mechanisms and, on this basis, to searches for new methods for its early diagnosis.

Primary biliary cirrhosis: Pathophysiology, clinical presentation and therapy

Primary biliary cirrhosis (PBC) is an autoimmune, slowly progressive, cholestatic, liver disease characterized by a triad of chronic cholestasis, circulating anti-mitochondrial antibodies (AMA), and characteristic liver biopsy findings of nonsuppurative destructive cholangitis and interlobular bile duct destruction. About 10% of PBC patients, however, lack AMA. A variant, called PBC-autoimmune hepatitis (AIH) overlap, is characterized by the above findings of PBC together with findings of elevated serum alanine aminotransferase, elevated serum immunoglobulin G, and circulating anti-smooth muscle antibodies, with liver biopsy demonstrating periportal or periseptal, lymphocytic, piecemeal necrosis. PBC is hypothesized to be related to environmental exposure in genetically vulnerable individuals. It typically occurs in middle-aged females. Prominent clinical features include fatigue, pruritis, jaundice, xanthomas, osteoporosis, and dyslipidemia. The Mayo Risk score is the most widely used and best prognostic system. Ursodeoxycholic acid is the primary therapy. It works partly by reducing the concentration and injury from relatively toxic bile acids. PBC-AIH overlap syndrome is treated with ursodeoxycholic acid and corticosteroids, especially budesonide. Obeticholic acid and fibrate are promising new, but incompletely tested, therapies. Liver transplantation is the definitive therapy for advanced disease, with about 70% 10-year survival after transplantation. Management of pruritis includes local skin care, dermatologist referral, avoiding potential pruritogens, cholestyramine, and possibly opioid antagonists, sertraline, or rifaximin. Management of osteoporosis includes life-style modifications, administration of calcium and vitamin D, and alendronate. Statins are relatively safe to treat the osteopenia associated with PBC. Associated Sjogren’s syndrome is treated by artificial tears, cyclosporine ophthalmic emulsion to stimulate tear production; and saliva substitutes, cholinergic agents, and scrupulous oral and dental care. Complications of cirrhosis from advanced PBC include esophageal varices, ascites, spontaneous bacterial peritonitis, hepatorenal syndrome, and hepatoma formation.

Anti-kelch-like 12 and anti-hexokinase 1: novel autoantibodies in primary biliary cirrhosis

BACKGROUND & AIMS

Using high-density human recombinant protein microarrays, we identified two potential biomarkers, kelch-like 12 (KLHL12) and hexokinase-1 (HK1), in primary biliary cirrhosis (PBC). The objective of this study was to determine the diagnostic value of anti-KLHL12/HK1 autoantibodies in PBC. Initial discovery used sera from 22 patients with PBC and 62 non-PBC controls. KLHL12 and HK1 proteins were then analysed for immunoglobulin reactivity by immunoblot and enzyme-linked immunosorbent assay (ELISA) in two independent cohorts of PBC and disease/healthy control patients.

METHODS

Serum samples from 100 patients with PBC and 165 non-PBC disease controls were analysed by immunoblot and samples from 366 patients with PBC, 174 disease controls, and 80 healthy donors were tested by ELISA.

RESULTS

Anti-KLHL12 and anti-HK1 antibodies were each detected more frequently in PBC compared with non-PBC disease controls (P < 0.001). Not only are both markers highly specific for PBC (≥95%) but they also yielded higher sensitivity than anti-gp210 and anti-sp100 antibodies. Combining anti-HK1 and anti-KLHL12 with available markers (MIT3, gp210 and sp100), increased the diagnostic sensitivity for PBC. Most importantly, anti-KLHL12 and anti-HK1 antibodies were present in 10-35% of anti-mitochondrial antibody (AMA)-negative PBC patients and adding these two biomarkers to conventional PBC assays dramatically improved the serological sensitivity in AMA-negative PBC from 55% to 75% in immunoblot and 48.3% to 68.5% in ELISA.

CONCLUSIONS

The addition of tests for highly specific anti-KLHL12 and anti-HK1 antibodies to AMA and ANA serological assays significantly improves efficacy in the clinical detection and diagnosis of PBC, especially for AMA-negative subjects.

High levels of soluble CTLA-4 are present in anti-mitochondrial antibody positive, but not in antibody negative patients with primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic autoimmune cholestatic liver disease frequently characterized by anti-mitochondrial autoantibodies (AMA). A minority of patients are AMA-negative. Cytotoxic-T-Lymphocyte-Antigen-4 (CTLA-4) is a surface molecule expressed on activated T-cells delivering a critical negative immunoregulatory signal. A soluble form of CTLA-4 (sCTLA-4) has been detected at high concentrations in several autoimmune diseases, and its possible functional meaning has been suggested. We aimed to evaluate sCTLA-4 concentration in sera of patients with PBC and to correlate it to immunological abnormalities associated with the disease. Blood samples were collected from 82 PBC-patients diagnosed according to international criteria (44 AMA-positive/MIT3-positive and 38 AMA-negative-MIT3-negative), and 65 controls. sCTLA-4 levels were evaluated by ELISA and Western blot. Increased sCTLA-4 concentrations were found in all AMA-positive PBC-patients, but in none of the AMA-negative ones, nor in normal controls or in controls with unrelated liver diseases. sCTLA-4 presence was associated with autoantibodies against MIT3, but not with nuclear autoantibodies (sp100, gp210). This is the first study to demonstrate that levels of sCTLA-4 are elevated in sera of PBC patients. However, they are clearly restricted to patients with AMA positivity, suggesting an immunological difference with respect to AMA-negative ones.

Less travelled roads in clinical immunology and allergy: drug reactions and the environmental influence

Allergy and clinical immunology are examples of areas of knowledge in which working hypotheses are dominant over mechanistic understanding. As such, sometimes scientific efforts follow major streams and overlook some epidemiologically prevalent conditions that thus become underestimated by the research community. For this reason, we welcome the present issue of Clinical Reviews in Allergy and Immunology that is dedicated to uncommon themes in clinical immunology and allergy. First, comprehensive discussions are provided for allergy phenomena of large potential impact in clinical practice such as reactions to cephalosporins or aspirin-induced asthma and in everyday life such as allergies to food additives or legumes. Further, the issue addresses other uncommon themes such as urticaria and angioedema, cercarial dermatitis, or late-onset inflammation to soft tissue fillers. Last, there will be discussion on transversal issues such as olfactory defects in autoimmunity, interleukin 1 beta pathway, and the search for new serological markers in chronic inflammation. As a result, we are convinced that this issue will be of help to clinicians involved in internal medicine as well as to allergists and clinical immunologists. More importantly, we are convinced that these discussions will be of interest also to basic scientists for the numerous translational implications.

Review article: controversies in the management of primary biliary cirrhosis and primary sclerosing cholangitis

BACKGROUND

Despite considerable advances over the last two decades in the molecular understanding of cholestasis and cholestatic liver disease, little improvement has been made in diagnostic tools and therapeutic strategies.

AIMS

To critically review controversial aspects of the scientific basis for common clinical practice in primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) and to discuss key ongoing challenges to improve patient management.

METHODS

We performed a literature search using PubMed and by examining the reference lists of relevant review articles related to the clinical management of PBC and PSC. Articles were considered on the background of the European Association for the Study of the Liver (EASL) and the American Association for the Study of Liver Diseases (AASLD) practice guidelines and clinical experience of the authors.

RESULTS

Ongoing challenges in PBC mainly pertain to the improvement of medical therapy, particularly for patients with a suboptimal response to ursodeoxycholic acid. In PSC, development of medical therapies and sensitive screening protocols for cholangiocarcinoma represent areas of intense research. To rationally improve patient management, a better understanding of pathogenesis, including complications like pruritis and fatigue, is needed and there is a need to identify biomarker end-points for treatment effect and prognosis. Timing of liver transplantation and determining optimal regimens of immunosuppression post-liver transplantation will also benefit from better appreciation of pre-transplant disease mechanisms.

CONCLUSION

Controversies in the management of PBC and PSC relate to topics where evidence for current practice is weak and further research is needed.

The overlap syndromes of autoimmune hepatitis

Autoimmune hepatitis has two major variant phenotypes in which the features of classical disease are co-mingled with those of primary biliary cirrhosis or primary sclerosing cholangitis. These overlap syndromes lack codified diagnostic criteria, established pathogenic mechanisms, and confident management strategies. Their clinical importance relates mainly to the identification of patients who respond poorly to conventional corticosteroid treatment. Scoring systems that lack discriminative power have been used in their definition, and a clinical phenotype based on pre-defined laboratory and histological findings has not been promulgated. The frequency of overlap with primary biliary cirrhosis is 7-13 %, and the frequency of overlap with primary sclerosing cholangitis is 8-17 %. Patients with autoimmune hepatitis and features of cholestatic disease must be distinguished from patients with cholestatic disease and features of autoimmune hepatitis. Variants of the overlap syndromes include patients with small duct primary sclerosing cholangitis, antimitochondrial antibody-negative primary biliary cirrhosis, autoimmune sclerosing cholangitis, and immunoglobulin G4-associated disease. Conventional corticosteroid therapy alone or in conjunction with ursodeoxycholic acid (13-15 mg/kg daily) has been variably effective, and cyclosporine, mycophenolate mofetil, and budesonide have been beneficial in selected patients. The key cholestatic features that influence the prognosis of autoimmune hepatitis must be defined and incorporated into the definition of the syndrome rather than rely on designations that imply the co-mingling of different diseases with manifestations of variable clinical relevance. The overlap syndromes in autoimmune hepatitis are imprecise, heterogeneous, and unfounded, but they constitute a clinical reality that must be accepted, diagnosed, refined, treated, and studied.

Potential Roles for Infectious Agents in the Pathophysiology of Primary Biliary Cirrhosis: What's New?

Primary biliary cirrhosis (PBC) is a progressive cholestatic liver disease serologically characterized by the presence of high-titer antimitochondrial antibodies and, histologically by chronic nonsuppurative cholangitis and granulomata. The aetiology of the disease remains elusive, although genetic, epigenetic, environmental, and infectious factors have been considered important for the induction of the disease in genetically prone individuals. The disease shows a striking female predominance and becomes clinically overt at the fourth to sixth decade. These characteristics have prompted investigators to consider infections that predominate in women at these ages as the likely candidates for triggering the disease. Recurrent urinary tract infections due to Escherichia coli were the first infections to be considered pathogenetically relevant. Over the years, several other microorganisms have been linked to the pathogenesis of PBC owing to epidemiological, immunological, microbiological, or experimental findings in animal models. Recent studies have provided data supporting the pathogenic role of Novosphingobium aromaticivorans and betaretroviruses. Several reports have linked other organisms to the induction of the disease and/or the maintenance of the auto-aggressive responses that are perpetuated over the course of the disease. This review highlights the findings of the most recent studies investigating the link between infections and PBC. We also discuss the close interplay of the infectious agents with other environmental and genetic factors, which may explain the multifaceted nature of this puzzling disease.

Role of autoimmunity in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune liver disease characterized by the presence of serum autoantibodies and chronic nonsuppurative destructive cholangitis. The pathogenesis of PBC involves environmental factors, genetic predisposition and loss of immune tolerance. In recent years, it has become univocally accepted that an inappropriately activated immune response is one of the most important factors in PBC. In this study, the role of autoimmunity in PBC is summarized and a feasible research orientation is recommended.

Analysis of the clinical relevance of antimitochondrial antibodies to the β- and γ-subunits of the F1F0-ATPase in patients with primary biliary cirrhosis

Background

In a recent study we showed that in patients with primary biliary cirrhosis (PBC) being positive or negative for anti-M2 antibodies reacting with the 2-oxoacid-dehydrogenase complex (ODC) also antibodies to the beta- and gamma-subunits of F₁F₀-ATPase (anti-β, anti-γ) occur. This is a mitochondrial enzyme but parts are also expressed on plasma membranes of endothelial cells. Here we wanted to analyse in more detail their clinical relevance.

Methods

Fifty-nine untreated and histologically defined PBC patients who had been followed for at least five years were included into the study (51 anti-M2 positive, 8 anti-M2 negative). Twenty-three of them were treated in the follow up with ursodeoxycholic acid (UDCA), eight received during a trial methotrexate (MTX). In 13 patients orthotopic liver transplantation (OLT) had to be performed. Serum samples before and during therapy were available. Patients were analysed with respect to laboratory parameters, disease activity and histological stages.

Patients’ sera were tested by ELISA for IgG- and IgM-antibodies against the beta- and gamma-subunits which had been recombinant expressed in E.coli and highly purified by electro-elution from SDS-gels after electrophoresis.

Results

Fifty-nine percent of the anti-M2 positive and 50% of the anti-M2 negative PBC patients had anti-β- and/or anti-γ-antibodies. There were no differences between anti-β- and/or anti-γ-antibody positive or negative patients with respect to biochemical parameters, immunoglobulins, histological stages or disease activity. Antibody reactivity significantly decreased during UDCA and MTX-treatment and also after OLT.

Conclusions

Antibodies to the β- and γ-subunits of F₁F₀-ATPase occur in anti-M2 positive and –negative PBC but do not have any relevance with respect to clinical activity or prognosis. However, in contrast to the anti-M2 antibodies they decrease during UDCA and immunosuppressive therapy.