Autoimmune tests in primary biliary cirrhosis

Pulmonary Manifestations among Patients with Primary Biliary Cirrhosis

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic liver disease caused by diffuse inflammation, destruction and fibrosis of the intrahepatic bile ducts, ultimately leading to cirrhosis, portal hypertension and liver failure. The pathogenesis of PBC is incompletely understood, but current data suggest roles for genetic susceptibility and environmental factors. PBC is often thought of as an organ-specific autoimmune disease, which mainly targets the liver; however, lung tissue is also a site for autoimmune involvement of PBC. The pulmonary manifestations of PBC include abnormalities in gas transfer and pulmonary function, subclinical alveolitis, interstitial lung disease, granulomatous lung disease, airway disease, pulmonary hypertension, pulmonary hemorrhage and pleural effusion.

[Primary biliary cirrhosis and pregnancy]

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease, asymptomatic during a protracted time, characterized by changes in the small-sized bile ducts near portal spaces. The etiology of PBC is undefined, but immunologic and environmental disturbances may contribute to the disease. Infertility is often associated with PBC and cirrhosis, but pregnancy may well occur in women with PBC and without cirrhosis or in some others with compensated cirrhosis. A pluridisciplinary approach including gastroenterologists and obstetricians is recommended. The patient must be closely monitored throughout her pregnancy with maternal and routine antenatal care. Medical treatment requires ursodeoxycholic acid (UDCA). In non-cirrhotic UDCA-treated women with PBC, pregnancy often follows a normal course with vaginal delivery. In cirrhotic patients, UDCA must be continued during pregnancy, esophageal and gastric varices must be evaluated before pregnancy, and endoscopic ligature is recommended for treating large varices. Additionally, beta-blocker therapy may be associated, especially when variceal rupture occurred previously. Elective cesarean section is recommended in patients with large esophageal or gastric varices because of the potentially increased risk of variceal bleeding during maternal expulsive efforts in case of vaginal delivery.

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.

Subgroups of Sjögren syndrome patients according to serological profiles

Sjögren Syndrome (SS) is a systemic, autoimmune disorder characterized by lymphocytic infiltration of the exocrine glands. Different clinical associations have been described for each of the diverse autoantibodies found in SS patients. Antibodies directed against the Ro/La ribonucleoprotein complexes have been correlated with younger age, more severe dysfunction of the exocrine glands and a higher prevalence of extraglandular manifestations. Anti-nuclear antibodies and rheumatoid factors have been associated to extraglandular manifestations and an active immunological profile, while cryoglobulins are markers of more severe disease and correlate to lymphoma development and death. Antibodies to cyclic citrullinated peptides are scarce in SS and have been linked in some cases to the development of non-erosive arthritis. Furthermore, the presence of anti-mitochondrial antibodies and anti-smooth muscle antibodies in the sera of primary SS patients is considered indicative of primary biliary cirrhosis and autoimmune hepatitis, respectively. In addition, anti-centromere antibodies have been associated with a clinical phenotype intermediate between primary SS and systemic sclerosis, while antibodies against carbonic anhydrase have been related to renal tubular acidosis. Finally, an association of anti-muscarinic antibodies with cytopenias and a higher disease activity has also been described in primary SS. In conclusion, although not all of the above mentioned antibodies are useful for predicting distinct patient subgroups in SS, knowledge of the clinical associations of the different autoantibody specificities encountered in SS can advance our understanding of the disease and improve patient management.

Increased Siglec-1 expression in monocytes of patients with primary biliary cirrhosis

OBJECTIVES

To evaluate Siglec-1 protein (CD169) and mRNA levels in peripheral blood monocytes of patients with primary biliary cirrhosis (PBC) and investigate its role in PBC pathogenesis by looking for correlations between Siglec-1 expression and key PBC associated biochemical indices.

METHODS

FACS analysis was used to identify the percentage of peripheral blood monocytes positive for both CD14 and Siglec-1 in (a) 45 PBC patients, (b) 40 patients with liver cirrhosis after hepatitis B infection and (c) 36 healthy controls. Siglec-1 mRNA was measured by real-time RT-PCR and serum biomarkers by routine biochemistry.

RESULTS

The percentage of CD14-Siglec-1 double positive cells was significantly higher (p< 0.01) in PBC patients than in healthy controls or cirrhosis post-hepatitis patients (13.68 +/- 2.44%, 1.0 +/- 0.2 %, and 4.1 +/- 0.5 %, respectively). Siglec-1 mRNA expression in the PBC group was 3.42 times higher than in healthy controls (p < 0.01).

CONCLUSION

We investigated the role of Siglec-1 in PBC by assessing its expression in mononuclear cells of PBC patients and levels of secreted cytokines in cell supernatants after Siglec-1 RNA interference. It is possible that elevated Siglec-1 expression in peripheral blood monocytes of PBC patients is correlated with monocyte-mediated inflammatory responses during the development of PBC.

[Sequelae of organ transplantation]

Transplant medicine has significantly changed the prognosis of diseases leading to terminal organ failure. It has evolved from an experimental procedure to standard therapy for liver, kidney and cardio-vascular diseases. Transplant medicine combines operative organ replacement with the management of severely ill patients before transplantation, as well as life-long follow-up of organ graft recipients. Ten year survival rates of 65% to over 90% have led to a steady increase of transplanted patients seen by general medical care providers which represents a challenge for practicing internists. Apart from organ-specific conditions, infectious, immunosuppressant-associated and metabolic consequences determine long-term survival. These include virus reactivation, graft rejection, anastomotic problems but more importantly general mortality determining factors such as diabetes, renal insufficiency and hypertension, which are often a consequence of immunosuppressant administration. They directly impact long-term survival. The awareness and treatment of these secondary conditions of organ transplantation in routine medical practice contributes significantly to secure the long term success of transplant medicine.

Anti-cyclic citrullinated peptide positivity in non-rheumatoid arthritis disease samples: citrulline-dependent or not?

BACKGROUND

Antibodies directed against citrullinated proteins (eg anti-cyclic citrullinated peptide (CCP)) have excellent diagnostic and good prognostic potential for rheumatoid arthritis. Type 1 autoimmune hepatitis (AIH-1) is a chronic liver disease characterised by a variety of serum autoantibodies. Recently, in a large group of patients with AIH-1 without clear rheumatoid arthritis overlap, a relatively high percentage (9%) of anti-CCP2 positivity was scored.

OBJECTIVES

To characterise the citrulline-dependence of the observed anti-CCP2 positivity in AIH-1 sera as well as in other groups of patients without rheumatoid arthritis (mainly rheumatic diseases).

METHODS

Serum samples of 57 patients with AIH-1 and 66 patients without rheumatoid arthritis, most of them reported as anti-CCP positive, were tested for citrulline-specific reactivity with a second generation anti-CCP kit, with the citrullinated and the corresponding non-citrullinated (arginine-containing) antigen. A subset of AIH-1 sera was also tested with a CCP1 ELISA (and arginine control).

RESULTS

The anti-CCP2 reactivity of most non-rheumatoid arthritis rheumatic diseases samples (87-93%) was citrulline-specific, whereas a relatively high percentage of AIH-1 samples (42-50%) turned out to be reactive in a citrulline-independent manner. The use of citrullinated and non-citrullinated CCP1 peptides confirmed a high occurrence of citrulline-independent reactivity in AIH-1 samples.

CONCLUSIONS

In rheumatoid arthritis and most non-rheumatoid arthritis rheumatologic disease sera, anti-CCP positivity is citrulline-dependent. However in some patients, particularly patients with AIH-1, citrulline-independent reactivity in the anti-CCP2 test can occur. A positive CCP test in a non-rheumatic disease (eg liver disease) should therefore be interpreted with care, and preferably followed by a control ELISA with a non-citrullinated antigen.

Diagnosing clinical subsets of autoimmune liver diseases based on a multivariable model

BACKGROUND

Diagnosing autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), primary sclerosing cholangitis, and other autoimmune liver diseases remains an imperfect process. We need a more accurate, evidence-based diagnostic system.

METHODS

We conducted a national survey and identified 988 cases of liver disease which did not satisfy the inclusion criteria for any liver disease of known etiology. We expected these cases to include autoimmune liver disease (AILD) and its variant forms. We selected 269 prototype cases for which histological re-evaluation of liver biopsy by independent expert hepatopathologists and the original diagnosis coincided. We did a multiple logistic regression analysis to determine explanatory variables that would distinguish cases of AIH and PBC from those of non-AIH and non-PBC, respectively. We constructed a multivariable diagnostic formula that gave AIH and PBC disease probabilities and validated it in a study of an additional 371 cases (validation group).

RESULTS

Based on the results of the statistical analysis, we selected three laboratory tests and four histological features as independent variables correlated to the diagnosis of both AIH and PBC. For the validation group, assuming that the original diagnosis was correct, the sensitivity and specificity for AIH were 86.3% and 92.4%, respectively. For PBC the sensitivity and specificity were 82.5% and 63.7%, respectively. A detailed analysis of inconsistent cases showed that the diagnosis based on the formula had given the correct diagnosis, for either AIH or PBC, except for 5 cases (1.3%) in which disease probability was low for both.

CONCLUSIONS

A seven-variable formula based on three laboratory tests and four histological features gives significant information for the diagnosis of AILD.

[Primary biliary liver cirrhosis and overlap syndrome. Diagnosis and therapy]

Primary biliary cirrhosis represents a chronic cholestatic liver disease of unknown etiology. It primarily affects females, is associated with extrahepatic immune-mediated syndromes, shows an immunogenetic association with HLA DR8, and displays serum autoantibodies, which makes an autoimmune etiology likely. The diagnosis is reached in patients with elevated alkaline phosphatase, gamma glutamyl transferase and bilirubin levels who exhibit normal bile ducts upon ultrasound examination, and in whom specific antimitochondrial autoantibodies are detectable. Half of all PBC patients additionally show specific antinuclear autoantibodies. Immunosuppressive therapy is ineffective; steroids, transplant immunosuppressants, colchicine, d-penicillamine and methotrexate are of limited clinical benefit. Ursodeoxycholic acid has few side effects and leads to a biochemical response and a delay of disease progression in most cases. When ursodeoxycholic acid therapy is ineffective an overlap syndrome with autoimmune hepatitis can be present, which can respond to steroid treatment. The only curative option is liver transplantation which should be considered when bilirubin levels exceed 100 microM/l.

The changing clinical presentation of recurrent primary biliary cirrhosis after liver transplantation

BACKGROUND

Recurrent disease after liver transplant is a significant problem. Recurrent primary biliary cirrhosis (RPBC) is a histologic diagnosis. Clinical data is unreliable in predicting or diagnosing recurrence. RPBC appears to have a changing clinical presentation in recent years.

MATERIALS AND METHODS

The diagnosis of RPBC after liver transplantation was made histologically. Data were obtained from our prospectively maintained liver-transplant database and evaluated statistically.

RESULTS

Between 1985 and 1999, 1,835 liver transplants were performed, 169 for PBC. One hundred fifty-six patients were evaluated (one patient received retransplantation, and 13 were excluded). Seventeen (10.9%) experienced recurrence. Median posttransplantation follow-up time was 72.1 months. Median time to recurrence was 49.6 months. Median follow-up time after recurrence was 11.5 months. Neither acute rejection episodes (P=0.34) nor OKT3 use (P=0.36) before diagnosis of recurrence was significant. The combination of cyclosporine, azathioprine, and prednisolone demonstrated recurrence in 6 of 71 (8.4%). Six of 49 (12.2%) patients treated with cyclosporine with or without mycophenolate mofetil and prednisolone experienced recurrence. Six of 36 (16.7%) patients treated with tacrolimus and prednisolone with or without mycophenolate mofetil experienced recurrence. Patients treated with cyclosporine had numerically fewer recurrences than those treated with tacrolimus (P=0.11).

CONCLUSIONS

Patients with RPBC demonstrated prolonged survival. Clinical factors did not aid in predicting RPBC. The clinical course of RPBC appears to be different than in the earlier years of liver transplantation. Immunosuppression may play a role. The use and type of antimetabolite drugs had no affect on recurrence. RPBC demonstrated a different clinical course with tacrolimus treatment (shorter time to recurrence) and increased incidence when compared with cyclosporine treatment. Controlled randomized studies are necessary to determine differences between tacrolimus and cyclosporine treatment, if any.

Characterization of M2 antibodies in asymptomatic Chinese population

AIM: To investigate the presence of M2 antibodies specific for primary biliary cirrhosis (PBC) in asymptomatic Chinese and identify patients with early PBC.

METHODS: Enzyme-linked immunosorbent assay (ELISA) tests for M2 antibodies to recombinant protein were performed in 5011 subjects (age range, 26-85 years; mean age: 45.81 ± 15.02 years) who took an annual physical examination. M2-positive subjects were further analyzed for immunoglobulin (Ig) classes and subclasses of M2 antibodies. Clinical, biochemical and immunological data were obtained for M2-positive subjects. In addition, ultrasonography (US) or endoscopic retrograde cholangio-pancreatography (ERCP) was performed to exclude any disorders other than PBC.

RESULTS: M2 antibodies were detected in 8 (0.16%) of the 5011 subjects studied. Of the 8 subjects, 7 were female and 1 was male (age range: 40-74 years). An unexplained increase of serum alkaline phosphatase (ALP) and gamma glutamyl transpeptidase (γ-GT) values, often to striking levels, was detected in 4 M2-positive subjects, 3 of them accorded with the diagnostic criteria recommended by the American Association for the Study of Liver Diseases, even though they had no symptoms of PBC (such as fatigue, pruritus or jaundice). Liver biopsy was performed in two M2-positive subjects and the histology was compatible with PBC in both cases.

CONCLUSION: Our data, while not assessing the true prevalence of asymptomatic PBC in the general population, suggest that asymptomatic PBC is much more common in China than has been supposed.

Construction and expression of a humanized M2 autoantigen trimer and its application in the diagnosis of primary biliary cirrhosis

AIM: To construct and express a humanized M₂ autoantigen trimer designated as BPO and to apply it in the diagnosis of primary biliary cirrhosis (PBC).

METHODS: cDNA fragments encoding M₂-reactive epitopes of pyruvate dehydrogenase complex E₂ (PDC-E₂), branched chain 2-oxo-acid dehydrogenase complex E₂ (BCOADC-E₂) and 2-oxo-glutarate dehydrogenase complex E₂ (OGDC-E₂) were amplified with PCR using total RNA extracted from human peripheral mononuclear blood cells. The fragments were cloned into the plasmid vector pQE-30 and then transferred into E. coli M15 (pREP4) for expression, which was induced by isopropylthio-β-D-galactoside. The expressed recombinant BPO protein was demonstrated by SDS-PAGE, Western-blotting and Immunoabsorption test, its antigenic reactivity and specificity were identified with seven M_---positive sera confirmed at Euroimmun Research Center (Germany). Using the purified BPO, M2 antibodies in sera from patients with PBC and other liver related diseases were detected with ELISA.

RESULTS: The expressed BPO was observed with both antigenic reactivity and specificity of M₂ autoantigens. The determination of M₂ antibodies by BPO with ELISA was more sensitive than using the Euroimmun's kit with the coefficients of variation less than 10% in both interassay and intraassay. With the newly established method, M2 antibodies were found in 100% (20/20) of patients with PBC. Six cases of liver disease with unknown etiology and 1 patient with drug induced liver injury had detectable levels of serum M₂ antibodies. There were also 2 patients with autoimmune cholangitis and 1 with autoimmune hepatitis showing M₂-antibody positive.

CONCLUSION: Compared with the routine immunofluorescence assay and commercially available assay kit using porcine heart mitochondrial protein as the antigen, the detection system established in the present study shows higher sensitivity and specificity and may be used as a powerful tool for the diagnosis of PBC.

Animal models of copper-associated liver disease

Recent advances in molecular biology have made possible the identification of genetic defects responsible for Wilson's disease, Indian childhood cirrhosis and copper toxicosis in Long Evans Cinnamon rats, toxic milk mice, and Bedlington terriers. The Wilson's disease gene is localized on human chromosome 13 and codes for ATP7B, a copper transporting P-type ATPase. A genetic defect similar to that of Wilson's disease occurs in Long Evans Cinnamon rats and toxic milk mice. Familial copper storage disorders in Bedlington and West Highland white terriers are associated with early subclinical disease, and copper accumulation with subsequent liver injury culminating in cirrhosis. The canine copper toxicosis locus in Bedlington terriers has been mapped to canine chromosome region CFA 10q26. Recently, a mutated MURR1 gene was discovered in Bedlington terriers affected with the disease. Idiopathic childhood cirrhosis is biochemically similar to copper toxicosis in Bedlington terriers, but clinically much more severe. Both conditions are characterized by the absence of neurologic damage and Kayser-Fleisher rings, and normal ceruloplasmin levels. A recent study added North Ronaldsay sheep to the list of promising animal models to study Indian childhood cirrhosis. Morphologic similarities between the two conditions include periportal to panlobular copper retention and liver changes varying from active hepatitis to panlobular pericellular fibrosis, and cirrhosis. Certain copper-associated disorders, such as chronic active hepatitis in Doberman pinschers and Skye terrier hepatitis are characterized by copper retention secondary to the underlying disease, thus resembling primary biliary cirrhosis in humans. Copper-associated liver disease has increasingly being recognized in Dalmatians. Copper-associated liver diseases in Dalmatians and Long Evans Cinnamom rats share many morphologic features. Fulminant hepatic failure in Dalmatians is characterized by high serum activities of alanine aminotransferase and aspartate aminotransferase, and severe necrosis of centrilobular areas (periacinar, zone 3) hepatocytes. Macrophages and surviving hepatocytes contain copper-positive material. Liver disease associated with periacinar copper accumulation has also been described in Siamese cats. Many questions regarding copper metabolism in mammals, genetic background, pathogenesis and treatment of copper-associated liver diseases remain to be answered. This review describes the similarities between the clinico-pathological features of spontaneous copper-associated diseases in humans and domestic animals.

Prevalence of coeliac disease in primary biliary cirrhosis and of antimitochondrial antibodies in adult coeliac disease patients in Italy

BACKGROUND

Although an association between primary biliary cirrhosis and coeliac disease has recently been reported in Northern Europe, there are still conflicting data concerning this issue.

AIM

To evaluate both the prevalence of coeliac disease in a series of primary biliary cirrhosis patients and that of antimitochondrial antibodies in a series of adult biopsy proven coeliac disease patients from Northern Italy.

PATIENTS AND METHODS

A total of 87 primary biliary cirrhosis patients (79 female, 8 male) were screened for both IgA-transglutaminase antibodies and antiendomysium antibodies and, in those with either IgA-transglutaminase antibodies or antiendomysium antibodies positivity, upper endoscopy with distal duodenum biopsy was offered. In those who refused upper endoscopy, the intestinal permeability test with lactulose/mannitol excretion was performed.

RESULTS

Antiendomysium antibodies positivity was detected in 3 subjects (3.4%), all of whom had serum IgA-transglutaminase antibodies above the normal range, and fulfilled the diagnosis of coeliac disease. Of 21 other patients with serum IgA-transglutaminase antibodies above the normal range, 17 underwent upper endoscopy which revealed normal duodenum architecture. The remaining 4 patients underwent the lactulose/mannitol excretion test which was within the normal range. Sera from 108 adult coeliac disease patients were tested for antimitochondrial antibodies and positivity was found in 4 patients (3.7%): all had normal liver biochemistry tests, whereas 2 of them also presented thyroid disease. Antibodies directed to the 74-kDa polypeptide of antimitochondrial antibodies were found in 3 out of 4 antimitochondrial antibodies+ve patients.

CONCLUSIONS

These results suggest an association between primary biliary cirrhosis and coeliac disease similar to that observed in the Northern European series. In conclusion, screening for coeliac disease with antiendomysium antibodies in primary biliary cirrhosis is justified, and screening for antimitochondrial antibodies is advisable in adult coeliac disease patients.