Antibodies In Primary Biliary Cirrhosis Research Articles

PWE-116 Gp210 and/or sp100 antibodies in primary biliary cirrhosis: predictors of cirrhosis/autoimmune (aih) overlap syndromes?

<h3>Introduction</h3> Primary Biliary Cirrhosis (PBC) is a progressive cholestatic liver disease, with Anti-mitochondrial antibodies (AMA) found in ∼ 95% of patients. Anti-GP210 and SP100 are suggested as additional markers in AASLD guidance, and may help in predicting disease prognosis. However, the role and benefit of anti-GP210 and SP100 testing in routine clinical practice is unclear. <h3>Method</h3> We conducted a retrospective study of all PBC patients (diagnosed according to AASLD criteria), across 3 hospitals in Surrey, England; serving a population 1.1million. Prospective ELISA testing for GP210 and SP100 antibodies were undertaken on all active PBC-patients in follow-up. Baseline characteristics (laboratory/clinical) and progression during follow-up were analysed and compared between both groups. <h3>Results</h3> 51 PBC patients were identified, with anti-GP210/SP100 demonstrated in 14 patients (27%); 9 with anti-SP100, 5 with anti-GP210. Demographic characteristics were similar between both groups: age 64 vs. 61 years, Females 80% vs. 70% in the PBC and GP210/SP100 groups. Consistent with the high sensitivity of AMA in PBC, only 1 (1/51) patient was AMA negative, and also negative for M2, GP210 and SP100. Baseline cirrhosis (imaging/biopsy) was present in 3/27 patients (11%) in the PBC group vs. 3/12 (25%) in the GP210/SP100 group. Quantitative mean M2 values were similar (100 vs. 96), as were baseline mean laboratory values (Bilirubin, ALT, ALP, GGT and IgM). Cirrhosis was present at follow-up (range 0.5–10 years) in 5/37 patients (13.5%) vs. 4/13 (31%) in the GP210/SP100 group. Treatment response to UDCA at one year (Barcelona criteria) was similar: 10/24 (42%) vs. 5/13 (38%) in the GP210/SP100 group. Post-treatment mean alkaline phosphatase levels were higher in the GP210/SP100 group 231 vs. 174 (p = 0.84). 8/51 PBC patients (16%) had diagnosed Autoimmune hepatitis (AIH)/PBC Overlap Syndrome (OS) (based on histological/serological features). OS cases were seen in 2/37 (5%) in the non-ANA group vs. 6/14 (43%) of those in the GP210/SP100 group, reaching statistical significance (p = 0.05); with no significant difference in ALT levels between the OS/non-OS groups. <h3>Conclusion</h3> Although a small sample, our findings support the role of anti-GP210/SP100 as possible markers of disease severity (cirrhosis), and suggest a role for these auto-antibodies in identifying patients with PBC/AIH overlap syndromes; even in the absence of a significant transaminitis. <h3>Disclosure of interest</h3> None Declared.

Anti-M3 muscarinic acetylcholine receptor antibodies in patients with primary biliary cirrhosis.

M3 muscarinic acetylcholine receptor (M3R) is expressed in biliary tracts as well as in exocrine glands. It is reported that some patients with primary biliary cirrhosis (PBC) carry autoantibodies against M3R. The aim of this study is to clarify the presence, potential use as diagnostic marker and clinical roles of anti-M3R antibodies in PBC. We synthesized peptides encoding the extracellular domains of human-M3R, including the N-terminal region, the first, second and third extracellular loops. Antibodies against these regions were examined by peptide-based enzyme-linked immunoassay in sera of 90 patients with PBC and 40 with chronic hepatitis C (CHC), 21 with non-alcoholic steatohepatitis (NASH), 10 with primary sclerosing cholangitis (PSC), 14 with obstructive jaundice, 10 with drug-induced liver injury and 42 healthy controls. Antibodies to the N-terminal, first, second and third loop were detected in 90.0% (81/90), 73.3% (66/90), 76.7% (69/90) and 66.7% (60/90) of PBC, in 67.5% (27/40), 10.0% (4/40), 67.5% (27/40) and 27.5% (11/40) of CHC, in 85.7% (18/21), 9.5% (2/21), 4.8% (1/21) and 57.1% (12/21) of NASH, in 60.0% (6/10), 20.0% (2/10), 60.0% (6/10) and 60.0% (6/10) of PSC, in 100.0% (14/14), 0% (0/14), 64.3% (9/14) and 78.6% (11/14) of obstructive jaundice, in 100.0% (10/10), 0% (0/10), 30.0% (3/10) and 10.0% (1/10) of drug-induced liver injury, and in 4.8% (2/42), 7.1% (3/42), 2.4% (1/42) and 2.4% (1/42) of the controls, respectively. A high frequency of PBC carried anti-M3R antibodies. Anti-M3R antibodies against the first loop of M3R are a potentially useful diagnostic marker for PBC.

High Frequency of Antiphospholipid Antibodies in Primary Biliary Cirrhosis

To evaluate, retrospectively, the frequency of autoantibodies of antiphospholipid syndrome (APLS) in Tunisian patients with primary biliary cirrhosis (PBC). We analyzed 80 PBC sera and 80 sera from blood donors. ELISA was used to determine the frequency of antibodies against cardiolipin (aCL IgG, IgA, and IgM) and beta 2 glycoprotein I (aβ2GPI IgG, IgA, and IgM). The frequency of antiphospholipid antibodies (aCL and/or aβ2GPI) was significantly higher in PBC patients than in controls (70 vs. 5%, P < 10(-6)). The frequency of aCL antibodies (IgG, IgA or IgM) was significantly higher in PBC patients than in the control group (23.7 vs. 3.7%, P = 0.0005). The frequencies of aCL IgA and aCL IgM in PBC patients' sera were significantly higher than those in the control group (10 vs. 0%, P = 0.003 and 20 vs. 2.5%, P = 0.001, respectively). Two patients of eighty (2.5%) had aCL IgG, aCL IgA and aCL IgM. The frequency of aβ2GPI antibodies (IgG, IgA, or IgM) was significantly higher in PBC patients than in the control group (70 vs. 1.2%, P < 10(-6)). The frequencies of aβ2GPI IgG, aβ2GPI IgA, and aβ2GPI IgM in PBC patients' sera were significantly higher in patients than in the control group (12.5 vs. 0%, P = 0.003; 62.5 vs. 1.2%, P < 10(-6); and 21.2 vs. 0%, P < 10(-4), respectively). Autoantibodies related to APLS (aCL and aβ2GPI) were present in the majority of patients with PBC, reflecting the ability of these antibodies to engage mediators of damage.

S1870 Clinical Significance of Cd38-Positive Plasma Cells Surrounding Interlobular Bile Ducts in Primary Biliary Cirrhosis (PBC)

Background/Aims: There has been increased interest in the potential role of B cells and antimitochondrial antibodies in PBC. Indeed a new paradigm in PBC includes the potential of B cells to act as both regulatory elements and as components of the inflammasone induced by apoptosis of biliary cells. We submit that a rigorous dissection of the inflammatory infiltrate in PBC will provide further insight on these issues. Materials and Methods: We took advantage of well-characterized Mabs to CD3, CD4, CD8, CD20, CD38, CD56, CD68, and pan-keratin antigens, and immunohistochemistry (IHC), to study the distribution of liver infiltrating CD38-positive plasma cells in 26 consecutive patients with PBC (AMA positive in 20 and negative in 6), all of whom had detailed staged clinical data. All data was “blindly” evaluated. We simultaneously studied 10 ageand gender-matched patients with chronic hepatitis C as a control. Results: Noteworthy within the IHC data was the presence of an intense coronal arrangement (CR) of CD38-positive cells around interlobular bile ducts, generally in specimens with chronic non-suppurative destractive cholangitis (CNSDC). In contrast, CD20-positive B lymphocytes (precursor cells of plasma cells) were found scattered and/or aggregated within the lymphoplasmocytic infiltration. Such CD20positive B cells also occasionally formed follicle-like aggregations but importantly were not observed in the proximity of CNSDC. PBC patients with CR demonstrated significantly higher titers of AMA (119.5±16.1 vs. 59.7±17.1, p=0.018) and lower levels of total cholesterol (TC) (195.1±9.0 vs. 223.6±9.6, p=0.04) than those without CR. Interestingly the CR correlated with titer of AMA (r=0.46), IgM (r=0.32), the presence of CNSDC (r=0.32) and inversely with age (r=-0.37), γ-GTP (r=-0.38) and TC (r=-0.41). In contrast, CD4and CD8-positive T lymphocyte infiltration was noted either in proximity of, or within the degenerated cholangioepithelium, suggesting the participation of these cells in the destructive processes of interlobular bile ducts. No CR was found in control subjects. Conclusion: The presence of CD38+ plasma cells surrounding biliary epithelium has clinical and serologic significance; further it correlates with disease progression exemplified by TC decrease and the development of florid duct lesions. These data further highlight the functional significance of B cells/ plasma cells; it also reflects a multilineage loss of tolerance in PBC. We submit that study of B cells in PBC should go beyond simple measurement of AMA titer and include rigorous phenotypical and functional dissection of the liver specific B cell lineage populations.

Catalytic domain of PDC-E2 contains epitopes recognized by antimitochondrial antibodies in primary biliary cirrhosis

To search for further immunodominant peptides of the pyruvate dehydrogenase complex E2-component (PDC-E2) recognized by antimitochondrial antibodies (AMA) in primary biliary cirrhosis (PBC). Sera from 95 patients with PBC were tested by enzyme-linked immunosorbent assay against 33 synthetic overlapping peptides (25 amino acids; aa) covering the entire length of the E2-subunit of PDC-E2. Furthermore, the inner lipoyl peptide 167-184 was used in an unlipoylated and a lipoylated form as well as coupled to ovalbumin. Sera from 11 AMA negative/ANA positive PBC patients, 63 patients with other liver disorders and 22 healthy blood donors served as controls. Of the 95 PBC-sera, 74% reacted with the peptide 475-499 and 58% with the peptide 407-431 located within the catalytic domain of PDC-E2. Patients with other disorders or healthy controls were positive in only up to 18%. Antibodies to the unlipoylated and lipoylated peptide 167-184 within the inner lipoyl domain were found in only 5% and 11% of the PBC sera, respectively; using ovalbumin-coupled peptides, the incidence increased up to 57% (unlipoylated form). Peptides within the catalytic site of PDC-E2 rather than the previously reported lipoyl binding peptide 167-184 may represent major immunodominant epitopes recognized by AMA in PBC.

Prevalence of gastric parietal cell antibodies and intrinsic factor antibodies in primary biliary cirrhosis

We investigated the prevalence of antibodies against gastric parietal cells (GPA), intrinsic factor antibodies (IFA) and the presence of pernicious anemia in a large cohort of primary biliary cirrhosis (PBC) patients as similar data is missing. 157 PBC patients and 357 controls (73 with autoimmune hepatitis (AIH), 35 primary sclerosing cholangitis (PSC), 45 HBV, 37 HCV, 36 alcoholic liver disease (ALD), 35 non-alcoholic fatty liver disease (NAFLD) and 96 healthy) were investigated for IgG-isotype-specific GPA and IFA by ELISAs and vitamin-B(12) levels by a microparticle enzyme immunoassay. The detection of IgG-GPA was significantly higher in PBC (31.8%) compared to AIH (10.9%; p=0.001), PSC (0%; p=0.000), HCV (13.5%; p=0.01), HBV (13.3%; p=0.006), ALD (8.3%; p=0.004), NAFLD (11.4%; p=0.003) and healthy (10.4%; p=0.001). IgG-IFA were detected in 12% of GPA-positive PBC patients and in none of the other liver diseases or in healthy (p=0.001). This reactivity was significantly associated with lower vitamin-B(12) levels compared to those with an IFA-negative test (p=0.025). A significant proportion of PBC patients had IgG-GPA and IFA compared to controls. IgG-IFA were detected only in GPA-positive PBC patients and associated with lower vitamin-B(12) levels compared to those with an IFA-negative test.

Mycoplasma antigens as a possible trigger for the induction of antimitochondrial antibodies in primary biliary cirrhosis

In primary biliary cirrhosis (PBC), autoreactivity mainly targets members of the pyruvate dehydrogenase complex (PDC). Because PDC subunits are expressed on the surface of mycoplasma and molecular mimicry may be one aetiological factor, we analysed the presence of mammalian and mycoplasma PDC-specific antibodies in PBC patients. Antibodies to porcine PDC and Mycoplasma pneumoniae (mp) antigens mpPDH-C (to be designated mpPDC-E2 chain), mpPDH-B (to be designated mpPDC-E1beta chain), mpCARDS TX and mpP1 were investigated in sera from 43 PBC patients, 19 patients with autoimmune hepatitis and 11 healthy controls by an enzyme-linked immunosorbent assay and Western blotting. To study the rate of acute mycoplasma infection, an adhesin P1-specific polymerase chain reaction (PCR) was performed. Immune reactivity to the mpPDC-E2 antigen was significantly enhanced in PBC patients (83.7%) as compared with controls (overall frequency of 36.7%), while antibodies to the porcine PDC-E2 chain were found only in PBC patients (88%) excluding a simple cross-reactivity of PDC-related antibodies. This observation was confirmed by inhibition studies demonstrating that porcine PDC did not inhibit mycoplasma PDC-specific antibodies and vice versa. The occurrence of antibodies to mpPDC seems to precede the occurrence of antibodies to porcine PDC. Infection with mycoplasma was equally distributed in the groups as evidenced by an antibody frequency comparable to CARDS TX and P1 and PCR reactivity. Because PBC patients show a significantly enhanced frequency of mpPDC-E2-related antibodies, besides other factors, molecular mimicry between surface molecules of mycoplasma and epitopes of the autoantigen may play a central role in the aetiopathology of PBC.

Diagnostik der Autoimmunerkrankungen

Autoantibodies play a key role in diagnostic laboratories as markers of autoimmune diseases. In addition to their role as markers they mediate diverse effects in vivo. Autoantibodies with protective effect have been described. Natural protective IgM autoantibodies against tumour-antigens of malignant cells or their precursors may contribute to increased survival rates of carcinoma patients. In a mouse model of systemic lupus erythematosus it has been shown that anti-dsDNA IgM autoantibodies protect from glomerular damage. In contrast, a direct pathogenic role of autoantibodies has been well established e.g. in myasthenia gravis or in Goodpasture syndrome. Similarly autoantibodies against SSA Ro52 are detrimental in neonatal lupus erythematosus with congenital heart block. Moreover, putatively protective autoantibodies may become pathogenic during the course of the disease such as the onconeuronal autoantibodies whose pathogenicity depends on their compartmentalisation. In patients with paraneoplastic syndromes tumour cells express proteins that are also naturally present in the brain. Anti-tumour autoantibodies which temporarily suppress tumour growth can provoke an autoimmune attack on neurons once having crossed the blood-brain barrier and cause specific neurological symptoms. Only a restricted number of autoantibodies are useful follow-up markers for the effectiveness of treatment in autoimmune diseases. Certain autoantibodies hold prognostic value and appear years or even decades before the diagnosis of disease such as the antimitochondrial antibodies in primary biliary cirrhosis or anti-citrullinated protein (CCP)-antibodies in rheumatoid arthritis. It is crucial to know whether the autoantibodies in question recognise linear or conformational epitopes in order to choose the appropriate detection methods. Indirect immunofluorescence microscopy remains a very useful tool for confirmation of results of commercially available immunoassays and for detection of special and rare autoantibodies that otherwise often remain undetected. Standardisation of autoimmune diagnostics is still underway and requires joint efforts by laboratories, clinicians and industry.

Anti-nuclear antibodies of primary biliary cirrhosis recognize 78–92-kD and 96–100-kD proteins of nuclear bodies

The specificities of anti-nuclear antibodies (ANA) reacting with multiple nuclear dots (MND-ANA) present in about 15% primary biliary cirrhosis sera were studied by Western blot analysis with nuclear fractions from a human cell line. Reactivity with two broad bands of 78-92 kD and 96-100 kD of the insoluble fraction was present exclusively in MND-ANA-positive sera. Antibodies eluted from these proteins specifically retained the immunofluorescence reactivity of MND-ANA. Immunomorphological analysis by a pre-embedding technique revealed that the antibody specifically binds to nuclear regions resembling in size and number nuclear bodies. Since these structures are absent in immature rate endometrial cell and can be induced by diethylstilbestrol, we tested MND-ANA by immunofluorescence on cryostat sections of uteri from hormone-treated and untreated immature rats. A strong reaction of nuclear dots was observed predominantly in endometrial cells of hormone treated rats. We thus conclude that MND-ANA present in primary biliary cirrhosis sera are directed against 78-92-kD and 96-100-kD nuclear proteins located in nuclear bodies.

Sera from patients with tuberculosis recognize the M2a-epitope (E2-subunit of pyruvate dehydrogenase) specific for primary biliary cirrhosis.

Anti-M2 antibodies in primary biliary cirrhosis (PBC) have been shown to react with the alpha-ketoacid dehydrogenase complex of the inner mitochondrial membrane consisting of six epitopes (E2 subunit of the pyruvate dehydrogenase complex (PDC), 70 kD; protein X of the PDC, 56 kD; alpha-ketoglutarate dehydrogenase complex, 52 kD; branched-chain alpha-ketoacid dehydrogenase, 52 kD; E1 alpha subunit of PDC, 45 kD; and E1 beta-subunit of PDC, 36 kD). These epitopes are also present in the M2 fraction which is a chloroform extract from beef heart mitochondria. The E2 subunit of the PDC at 70 kD (M2a), especially, is a major target epitope which is recognized by about 85% of all PBC sera. However, analysing sera from 28 patients with active pulmonary tuberculosis it became evident that 12 (43%) also recognized the PDC-E2 subunit (M2a), as shown by Western blotting using the M2 fraction, the purified PDC, and the recombinant PDC-E2. In contrast, only two of 82 patients with other bacterial and viral infections including 25 patients with Escherichia coli infections reacted with the PBC-specific epitope at 70 kD. Naturally occurring mitochondrial antibodies (NOMA) were present in 54% of the patients with tuberculosis and in 50% of patients with other infectious disorders. They recognized either a determinant at 65 kD (epsilon) or at 60/55 kD (zeta/eta). None of the sera from 100 blood donors had anti-M2 but 14 had NOMA. Testing anti-M2 and NOMA-positive marker sera by Western blotting against membrane fractions derived from mycobacteria and E. coli it could be shown that--like mammalian mitochondria--they contain both the PBC-specific M2 antigen as well as the non-PBC-specific naturally occurring mitochondrial antigen system (NOMAg). The observation that PBC-specific antibodies were preferentially induced in patients suffering from a mycobacterial infection may provide some new clues to the still unknown etiology of PBC.

The value of antinuclear antibodies in primary biliary cirrhosis

Although autoantibodies have been used for the diagnosis of primary biliary cirrhosis (PBC), their role has not been clarified. In this study, we try to explore the value of gp210 antibody and anti-centromere antibodies (ACA) in PBC. Anti-gp210 and ACA were tested in 140 PBC patients by ELISA and indirect immunofluorescence respectively. Their association with clinical, pathological data and prognosis was analysed. 30.5% of PBC patients had positive anti-gp210 antibody and 29.2% had ACA. The anti-gp210 antibody positive group had higher Mayo risk scores and lower serum albumin levels compared to the negative one. Patients with positive anti-gp210 antibody were more likely to develop hepatic failure (p<0.05, OR=9.8460, 95% CI: 1.067-90.901) than patients with negative anti-gp210 antibody. More patients with positive ACA developed portal hypertension than patients with negative ACA (p<0.05, OR=9.259; 95% CI: 1.027-88.410). Furthermore, concurrent Sjögren's syndrome (SjS) and PBC was significantly more likely in the ACA positive group than in the negative ones (68.4% in ACA positive group, 20.7% in ACA negative group p<0.001). Both anti-gp210 antibody and ACA are related to severe disease course and poor prognosis. For PBC patients with positive ACA, further examinations should be made to detect underlying SjS.

Anti-Saccharomyces cerevisiae Antibodies in Primary Biliary Cirrhosis

The aim of this study was to evaluate, retrospectively, the frequency of anti-Saccharomyces cerevisiae antibodies (ASCA) in patients with primary biliary cirrhosis (PBC). ASCA, IgG, and IgA, were determined by ELISA in sera of 95 PBC patients; 80 healthy blood donors served as controls. The frequency of ASCA (IgG or IgA) was significantly higher in PBC patients than in the control group (24.2% vs 3.7%, P = 0.0001). The frequency of ASCA IgG and ASCA IgA in PBC patients was also significantly higher than that found in the control group (18.9% vs 2.5%, P = 0.0006 and 11.6% vs 1.2%, P = 0.007, respectively). Six patients out of 95 (6.3%) had both ASCA IgG and ASCA IgA; in contrast, none of the control group had both isotypes (P = 0.02). There was no correlation between ASCA levels and mitochondrial autoantibodies (AMA) titres in PBC patients. We conclude that ASCA are common in patients with PBC.

Characterization of the antibodies to p62 nucleoporin in primary biliary cirrhosis using human recombinant antigen

Reactivity of sera from patients with primary biliary cirrhosis (PBC) with a 60 kDa component of nuclear pore complexes (NPCs), purified by affinity chromatography on wheat-germ agglutinin (WGA)-Sepharose, was previously detected. Recently, clinical significance of the anti-NPC antibodies in PBC became evident. In the light of recent reports, indicating the correlation of the anti-NPC antibodies with severity and progression of the disease, the characterization of the reactive antigens is becoming essential in the clinical management of patients with PBC. Since accurate autoantibody detection represents one of the fundamental requirements for a reliable testing, we have generated a human recombinant p62 protein and validated an immunoprecipitation assay for the detection of anti-p62. We also demonstrated that the generated human recombinant p62 nucleoporin was modified by N-acetylglucosamine residues. More than 50% of tested PBC sera precipitated (35)S-radioactively labeled p62 recombinant nucleoporin and 40% recognized this recombinant antigen by immunoblotting. We compared the reactivity of PBC sera with rat and human nucleoporin. The incidence of anti-p62 nucleoporin positive PBC sera increased by 15% when human recombinant antigen was used. The titer of autoantibodies in p62-positive PBC samples strongly varied. Preadsorption of the PBC sera with p62 recombinant protein completely abolished their reactivity with the antigen. In conclusion, this study unequivocally proves that autoantibodies reacting with the 60 kDa component of NPCs target p62 nucleoporin and, more importantly, provide a better antigen source for future evaluations of the clinical role of anti-p62 in PBC.

Diagnostic Relevance and Clinical Significance of the New Enhanced Performance M2 (MIT3) ELISA for the Detection of IgA and IgG Antimitochondrial Antibodies in Primary Biliary Cirrhosis

Antimitochondrial antibodies (AMAs) are the serological hallmark of primary biliary cirrhosis (PBC). We evaluated the sensitivity and specificity of a new M2 enhanced performance enzyme-linked immunosorbent assay (ELISA) (MIT3) for the detection of IgG- and IgA-specific isotypes of AMA in PBC patients including a number of PBC patients negative for AMA by indirect immunofluorescence (IIF) as well as in patients with diverse, non-PBC disorders. We also investigated the clinical significance of IgG and IgA AMA in PBC. One hundred and three Greek PBC patients including 27 with AMA IIF-negative at the time of the investigation, 29 with autoimmune hepatitis-1 (AIH-1), 12 with primary sclerosing cholangitis (PSC), 26 with hepatitis C virus (HCV), 15 with hepatitis B virus (HBV), and 29 healthy were investigated for AMA (IgG and IgA) using the MIT3-based ELISAs (INOVA Diagnostics, San Diego, CA). The samples were also tested by conventional anti-M2 ELISA (INOVA Diagnostics, Inc.). The IgG MIT3-based ELISA significantly increased AMA detection in the cohort of PBC patients, over 26% of whom were AMA IIF-negative, from 63.1% by the conventional anti-M2, and 73.7% by IIF to 79.6% by MIT3-based ELISA (p<0.001). IgA AMAs were detected in 47.6% patients. Overall, IgG/IgA AMAs were detected in 84/103 (81.6%). IgG MIT3-based ELISA detected 12/27 IIF AMA-negative samples (44.4%), while IgG/IgA MIT3-based ELISAs detected 13/27 IIF AMA-negative patients (48.1%). The specificities of MIT3-based ELISAs (IgG and IgA) were 82.8% and 89.7%, respectively, in AIH-1, 100% and 93.3%, respectively, in HBV, 100% in PSC, and 96% and 93.3%, respectively, in HCV. Patients positive for IgG AMA had significantly more severe disease as shown by worse histology and elevated biochemical markers; IgG and IgA AMA titers were associated positively with the Mayo risk score but none of the isotypes were able to predict disease outcome. The new IgG and IgA MIT3-based ELISAs seem to have higher specificity and sensitivity for AMA detection than IIF and the conventional anti-M2. Interestingly, these assays were able to unmask AMA presence in almost half of the AMA-negative samples by IIF. These findings may suggest the use of MIT3-based ELISAs as first-line investigation for AMA detection, particularly, when the laboratories are unfamiliar with the use and interpretation of the IIF patterns of AMA. The presence of IgG AMA seems to characterize PBC patients with more severe disease, but both IgG and IgA isotypes of AMAs were not predictive markers of disease outcome.

Autoimmune liver disease: overlap and outliers

The three main categories of autoimmune liver disease are autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC); all are well-defined entities with diagnosis based upon a constellation of clinical, serologic, and liver pathology findings. Although these diseases are considered autoimmune in nature, the etiology and possible environmental triggers of each remain obscure. The characteristic morphologic patterns of injury are a chronic hepatitis pattern of injury with prominent plasma cells in AIH, destruction of small intrahepatic bile ducts and canals of Hering in PBC, and periductal fibrosis and inflammation involving larger bile ducts with variable small duct damage in PSC. Serological findings include the presence of antimitochondrial antibodies in PBC, antinuclear, anti-smooth muscle, and anti-LKM antibodies in AIH, and pANCA in PSC. Although most cases of autoimmune liver disease fit readily into one of these three categories, overlap syndromes (primarily of AIH with PBC or PSC) may comprise up to 10% of cases, and variant syndromes such as antimitochondrial antibody-negative PBC also occur. Sequential syndromes with transition from one form of autoimmune liver disease to another are rare.

Novel nucleolar cell cycle related antibody in primary biliary cirrhosis

Introduction. Primary biliary cirrhosis (PBC) is a chronic cholestatic autoimmune liver disease characterised by the presence of anti-mitochondrial antibodies (AMA) and specific anti-nuclear antibodies (ANA). Characterisation of ANA specificities is essential for the diagnosis of PBC especially in AMA negative patients. In this study we evaluated ANA profile in PBC sera and we found a peculiar nucleolar reactivity differentially expressed during the cell cycle.

Anti-extractable nuclear antigens (ENA) antibodies in primary biliary cirrhosis

Anti-extractable nuclear antigens (ENA) antibodies in primary biliary cirrhosis

Tubulointerstitial Nephritis and Fanconi Syndrome in Primary Biliary Cirrhosis

Primary biliary cirrhosis is a chronic cholestatic liver disease of unknown cause that predominantly affects middle-aged women. Distal tubular acidosis is the main renal complication of primary biliary cirrhosis. Tubulointerstitial nephritis and Fanconi syndrome have been reported more rarely. We report on 2 patients with primary biliary cirrhosis who presented with tubulointerstitial nephritis and Fanconi syndrome and review similar cases published previously. Serum from 1 patient exerted an inhibitory effect on pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase, 2 mitochondrial enzymes that are the main targets of antimitochondrial antibodies in primary biliary cirrhosis. Antimitochondrial antibodies may have a role in the genesis of tubulointerstitial nephritis and Fanconi syndrome, 2 typical renal features of mitochondrial cytopathies. Tubulointerstitial nephritis and Fanconi syndrome have to be added to the spectrum of renal diseases associated with primary biliary cirrhosis.

Antinuclear Antibodies in Primary Biliary Cirrhosis

Patients with primary biliary cirrhosis (PBC) generate a variety of autoantibodies, which are primarily directed against mitochondrial antigens (AMA). However, a subgroup of patient sera are also positive for antibodies to nuclear components (ANAs). At indirect immunofluorescence (IIF), PBC sera mostly produce homogeneous, nuclear dot, speckled, centromere, or rim-like patterns. During the last two decades, a number of nuclear structures have been recognized as specific targets of ANA in PBC. These include Sp100 and promyelocytic leukemia proteins, which generate a nuclear dot IIF pattern, and two components of the nuclear pore complex specifically associated with a perinuclear pattern (i.e., gp210 and p62). In recent years, the clinical significance of ANA in PBC has been widely investigated and data indicate that, unlike AMAs, PBC-specific ANAs correlate with disease severity and may therefore be a marker of poor prognosis.

Clinical Relevance of Antiphospholipid Antibodies in Primary Biliary Cirrhosis

Primary biliary cirrhosis (PBC) is a cholestatic liver disease characterized by the presence of antimitochondrial autoantibodies (AMAs), but also with reactivities to other autoantigens. Recent studies showed that antibodies to phospholipids (APAs) represent an important group of autoantibodies identified in patients with PBC. In this study different types of APAs were identified in the sera of patients with PBC and autoimmune hepatitis (AIH) and control subjects. Sera from patients with PBC and AIH were tested for the presence of antibodies directed against cardiolipin (CL), phosphatidylserine (PS), and to beta(2)-glycoprotein I (beta(2)-GPI). Furthermore, an in-house test for antithromboplastin antibodies was performed. Antinuclear antibodies (ANAs) and antimitochondrial antibodies (AMAs) were tested with standard tests. IgM anti-PS antibodies were found in 75% of the 51 PBC patients, but only in 4% of the 48 AIH patients (P < 0.0001). IgM anti-CL antibodies were more frequently detected in AIH than in PBC (75% vs. 89%; P = 0.045). IgM anti-beta(2)-GPI antibodies were observed more frequently in patients with AIH (83%) than with PBC (59%; P = 0.007). The APAs of the IgG type did not differ significantly between the groups of patients. Considering the clinical/laboratory parameters, the levels of alkaline phosphatase (P = 0.017), glutamate pyruvate transaminase (P = 0.035), and glutamate oxalacetate transaminase (P = 0.034) were significantly higher in PBC patients who were positive for IgM anti-PS antibodies than in the anti-PS antibody-negative patients. In conclusion, APAs are present in PBC patients with a higher level of the disease or more intense liver damage than in patients without APAs. Thus IgM anti-PS antibodies represent a new marker of activity in PBC patients.