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We describe a 53-year-old woman with primary Sjögren's syndrome and tubulointerstitial nephritis showing distal renal tubular acidosis and Fanconi syndrome. The patient showed high serum IgM levels and positivity for antimitochondrial antibodies, although her liver function was in normal range. According to our literature review, 75% of patients with tubulointerstitial nephritis who were positive for antimitochondrial antibodies showed Fanconi syndrome, suggesting that these antibodies may directly be associated with the pathophysiology of Fanconi syndrome.

Aim: To determine the prevalence and significance of primary biliary cirrhosis (PBC)-specific autoantibodies in first-degree relatives (FDRs) of Greek PBC patients., Methods: The presence of antimitochondrial antibodies (AMA) and PBC-specific antinuclear antibodies (ANA) were determined using indirect immunofluorescence assays, dot-blot assays, and molecularly based enzyme-linked immunosorbent assays in 101 asymptomatic for liver-related symptoms FDRs of 44 PBC patients. In order to specify our results, the same investigation was performed in 40 healthy controls and in a disease control group consisting of 40 asymptomatic for liver-related symptoms FDRs of patients with other autoimmune liver diseases namely, autoimmune hepatitis-1 or primary sclerosing cholangitis (AIH-1/PSC)., Results: AMA positivity was observed in 19 (only 4 with abnormal liver function tests) FDRs of PBC patients and none of the healthy controls. The prevalence of AMA was significantly higher in FDRs of PBC patients than in AIH-1/PSC FDRs and healthy controls [18.8%, 95% confidence interval (CI): 12%-28.1% vs 2.5%, 95% CI: 0.1%-14.7%, P = 0.01; 18.8%, 95% CI: 12%-28.1% vs 0%, 95% CI: 0%-10.9%, P = 0.003, respectively]. PBC-specific ANA positivity was observed in only one FDR from a PSC patient. Multivariate analysis showed that having a proband with PBC independently associated with AMA positivity (odds ratio: 11.24, 95% CI: 1.27-25.34, P = 0.03) whereas among the investigated comorbidities and risk factors, a positive past history for urinary tract infections (UTI) was also independently associated with AMA detection in FDRs of PBC patients (odds ratio: 3.92, 95% CI: 1.25-12.35, P = 0.02)., Conclusion: In FDRs of Greek PBC patients, AMA prevalence is significantly increased and independently associated with past UTI. PBC-specific ANA were not detected in anyone of PBC FDRs.

• Occasionally, AMA -the specific marker of PBC- can be detected in AIH patients. • The clinical significance of this finding remains obscure. • AIH severity and response to therapy were similar in AMA(+) and AMA(-) AIH patients. • AMA(+) AIH patients had higher risk to develop histological bile duct injury. • AMA(+) AIH patients with non-specific bile duct injury had higher risk to progress. Antimitochondrial antibodies (AMA) are specific markers for the diagnosis of primary biliary cholangitis (PBC) but can also be found occasionally in patients with autoimmune hepatitis (AIH). The present large multicentre cohort study assessed the prevalence and significance of AMA in AIH-patients. 123 AMA-positive AIH-patients were investigated and compared with 711 age-matched AMA-negative AIH-patients and 69 patients with AIH/PBC variant. AMA prevalence in AIH-patients was 5.1% (range: 1.2%-11.8%). AMA-positivity was associated with female sex (p = 0.031) in AMA-positive AIH-patients but not with liver biochemistry, bile duct injury on liver biopsy, disease severity at baseline and response to treatment compared to AMA-negative AIH-patients. Comparing AMA-positive AIH-patients to those with AIH/PBC variant, there was no difference in disease severity. Regarding liver histology, AIH/PBC variant patients were characterized by the presence of at least one feature of bile duct damage (p <0.001). Response to immunosuppressive treatment was similar among groups. From AMA-positive AIH patients only those with evidence of non-specific bile duct injury had higher risk to progress to cirrhosis (HR=4.314, 95%CI: 2.348–7.928; p <0.001). During follow-up, AMA-positive AIH-patients had higher risk to develop histological bile duct injury (HR 4.654, 95%CI 1.829–11.840; p = 0.001). AMA presence is relatively common among AIH-patients, but their clinical significance seems important only when they co-exist with non-specific bile duct injury at the histological level. Therefore, a careful evaluation of liver biopsy seems of utmost importance in these patients. [Display omitted] [ABSTRACT FROM AUTHOR]

Introduction: A proportion of patients with drug-induced liver injury (DILI) present with autoantibodies, which has led to the current concept of autoimmune-like DILI. However, no standardized definition exists and the clinical relevance has not been studied in detail yet. Methods: 143 patients with DILI enrolled in a prospective study were analyzed. DILI diagnosis was based on the monocyte-derived hepatocyte-like cell test and supported by Roussel Uclaf Causality Assessment Method (RUCAM) and expert adjudication. Testing for antinuclear antibodies (ANA) and antimitochondrial antibodies (AMA) was performed using immunofluorescence. ANA titers ≥1:100 were considered positive and ≥1:400 clinically relevant; AMA positivity was considered at titers ≥1:100. Results: 67% exhibited ANA ≥1:100 and 29% ANA ≥1:400; 10% were AMA positive. There was no significant correlation between the ANA titers and the causative drug, while AMA positive patients had taken nonsteroidal anti-inflammatory drugs more frequently. No difference was seen regarding clinical characteristics or laboratory parameters in patients with ANA ≥1:400, while patients with positive AMA presented with higher aminotransferases, bilirubin, and international normalized ratio. Significantly higher proportions of patients with ANA ≥1:400 or AMA positivity exhibited elevated immunoglobulin G levels. AMA positivity but not elevated ANA titers correlated with a higher proportion of Hy's law positivity. Conclusion: A closer look in a causality proven DILI cohort provided no evidence that presence of ANA titers is specific for DILI by a certain medication. AMA rather than ANA positivity was related to a more pronounced liver injury. [ABSTRACT FROM AUTHOR]

Background: Systemic sclerosis (SSc) and primary biliary cholangitis (PBC) are autoimmune diseases that may occur concomitantly and are both strongly associated with disease-specific autoantibodies. This study investigated the prevalence and fine specificity of PBC-specific serology (PBC-Ab) and associations with the SSc-subtypes and SSc-specific antibodies as well as the association with cholestatic liver enzymes. Furthermore, three different techniques for the detection of PBC-Ab were compared. Methods: Serum of 184 Belgian SSc patients with a known SSc-antibody profile, was analyzed for PBC-Ab (antimitochondrial antibodies [AMA], anti-Gp210, anti-Sp100 and anti-PML) using indirect immunofluorescence (IIF) analysis on human epithelioma-2000 (HEp-2000) cells (ANA-IIF, Immunoconcepts) and liver-kidney-stomach tissue sections (IIF-LKS) (Menarini), and a line immunoblot (LB) (EuroImmun). Alkaline phosphatase/γ-glutamyl transferase (ALP/GGT) were evaluated at time of first sampling (t0) and after 3 years of follow-up (t3). Results: PBC-Ab were present in 13% of patients and significantly correlated with centromere antibodies (anti-CENP-B), but not correlated with the limited cutaneous SSc subgroup (lcSSc). The most frequent reactivities were AMA (11%, with 9% AMA-M2) and Sp-100 antibodies (5%), showing a major overlap. There was no relevant association between the presence of PBC-Ab and ALP or GGT elevation at t0 nor at t3. Detection of AMA with IIF-LKS is comparable to LB. ANA-IIF screening was less sensitive compared to LB. Conclusions: A wide range of PBC-Ab is detectable in SSc in the absence of cholestatic liver enzyme elevations, even after 3 years of follow-up. However, as these antibodies may precede PBC-disease up to 10 years further prospective follow-up of our cohort will be necessary. [ABSTRACT FROM AUTHOR]

Testing for liver-related autoantibodies should be included in the workup of patients with hepatitis or cholestasis of unknown origin. Although most of these autoantibodies are not disease specific, their determination is a prerequisite to diagnose autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC), and they are components of the diagnostic scoring system in these diseases. In primary sclerosing cholangitis (PSC), on the other hand, autoantibodies are frequently present but play a minor role in establishing the diagnosis. In PSC, however, data on antibodies suggest a link between disease pathogenesis and the intestinal microbiota. This review will focus on practical aspects of antibody testing in the three major autoimmune liver diseases AIH, PBC, and PSC. [ABSTRACT FROM AUTHOR]

Autoantibodies in hepatitis C virus-infected patients may indicate autoimmune hepatitis or other immune-mediated diseases. This may impact safety and efficacy of interferon-based therapy of chronic hepatitis C. We investigated the association between a positive test result for a variety of autoantibodies and the initiation and efficacy of therapy for chronic hepatitis C. We analysed an observational cohort of 24 306 patients for an association between autoantibodies and treatment outcome. 8241 patients were tested simultaneously for antinuclear antibodies ( ANA), liver kidney microsomal antibodies ( LKM), smooth muscle antibodies ( SMA) and antimitochondrial antibodies ( AMA). Matched-pair analysis was performed matching one autoantibody-positive patient to three controls. Control patients had negative tests for all four antibodies. Analyses were performed for patients with a single positive autoantibody test and for patients with multiple positive autoantibody tests. A positive test result for ANA, LKM, SMA or AMA did not affect the physician's decision to initiate therapy with pegylated interferon and ribavirin. In addition, a positive test for one or multiple autoantibodies did not adversely affect sustained virologic response. There was no difference in fibrosis stage or alanine transaminase at baseline or during therapy irrespective of antibody status. Thyroid dysfunction was more frequent in patients with positive LKM antibodies ( P = 0.004). Initiation of therapy for chronic hepatitis C and outcome were not affected by the presence of ANA, LKM, SMA or AMA. Routine testing of these autoantibodies seems not warranted. Determination of autoantibodies should be guided by individualized clinical decisions. [ABSTRACT FROM AUTHOR]

The association between celiac disease and primary biliary cirrhosis is well established. The breakdown of gut-liver axis equilibrium plays a central role in the development of immune disorders involving the small bowel and liver. In celiac disease, immunologically active molecules generated from the cross-linking between tissue transglutaminase and food/bacterial antigens reach the liver through the portal circulation owing to the increased intestinal permeability. A molecular mimicry between bacterial antigens and the pyruvate dehydrogenase E2 component, recognized by antimitochondrial autoantibodies, may have a role in primary biliary cirrhosis pathogenesis. An aberrant intestinal T lymphocyte homing to the liver may contribute to trigger immune hepatic damage. Both celiac disease and primary biliary cirrhosis share several features, including a higher prevalence in females, autoimmune comorbidities and specific autoantibodies. Reciprocal screening for both diseases is recommended, as an early diagnosis with the appropriate treatment can improve the outcome of these patients. [ABSTRACT FROM AUTHOR]

Abstract: Environmental stimulation is a major factor in the initiation and perpetuation of autoimmune diseases. We have addressed this issue and focused on primary biliary cirrhosis (PBC), an autoimmune disease of the liver. Immunologically, PBC is distinguished by immune mediated destruction of the intra hepatic bile ducts and the presence of high titer antimitochondrial autoantibodies (AMA) directed against a highly specific epitope within the lipoic acid binding domain of the pyruvate dehydrogenase E2 subunit (PDC-E2). We submit that the uniqueness of AMA epitope specificity and the conformational changes of the PDC-E2 lipoyl domain during physiological acyl transfer could be the lynchpin to the etiology of PBC and postulate that chemical xenobiotics modification of the lipoyl domain of PDC-E2 is sufficient to break self-tolerance, with subsequent production of AMA in patients with PBC. Indeed, using quantitative structure activity relationship (QSAR) analysis on a peptide-xenobiotic conjugate microarray platform, we have demonstrated that when the lipoyl domain of PDC-E2 was modified with specific synthetic small molecule lipoyl mimics, the ensuing structures displayed highly specific reactivity to PBC sera, at levels often higher than the native PDC-E2 molecule. Hereby, we discuss our recent QSAR analysis data on specific AMA reactivity against a focused panel of lipoic acid mimic in which the lipoyl di-sulfide bond are modified. Furthermore, data on the immunological characterization of antigen and Ig isotype specificities against one such lipoic acid mimic; 6,8-bis(acetylthio)octanoic acid (SAc), when compared with rPDC-E2, strongly support a xenobiotic etiology in PBC. This observation is of particular significance in that approximately one third of patients who have taken excessive acetaminophen (APAP) developed AMA with same specificity as patients with PBC, suggesting that the lipoic domain are a target of APAP electrophilic metabolites such as NAPQI. We submit that in genetically susceptible hosts, electrophilic modification of lipoic acid in PDC-E2 by acetaminophen or similar drugs can facilitate loss of tolerance and lead to the development of PBC. [Copyright &y& Elsevier]

Primary biliary cirrhosis (PBC) is a chronic inflammatory disease that affects small intrahepatic biliary ducts leading to liver cirrhosis. PBC primarily affects middle-aged women. The most typical symptoms are pruritus and fatigue. PBC is diagnosed on the basis of appearance of antimitochondrial autoantibodies, raised activity of alkaline phosphatase in serum and characteristic histopatologic features of liver biopsy. Treatment with ursodeoxycholic acid is a basic therapy of the disease but in some cases inefficient. Knowledge about genetic and environmental factors that cause PBC should allow to prevent the development of the disease and introduce an effective targeted treatment. [ABSTRACT FROM AUTHOR]

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease in which an immune-mediated injury targets the small intrahepatic bile ducts. PBC is further characterized by highly specific serum antimitochondrial autoantibodies (AMAs) and autoreactive T cells, a striking female predominance, a strong genetic susceptibility and a plethora of candidate environmental factors to trigger the disease onset. For these reasons, PBC appears ideal to represent the developments of the clonal selection theory over the past decades. First, a sufficiently potent autoimmunogenic stimulus in PBC would require the coexistence of numerous pre-existing conditions (mostly genetic, as recently illustrated by genome-wide association studies and animal models) to perpetuate the destruction of the biliary epithelium by the immune system via the persistence of forbidden clones. Second, the proposed modifications of mitochondrial autoantigens caused by infectious agents and/or xenobiotics well illustrate the possibility that peculiar changes in the antigen structure and flexibility may contribute to tolerance breakdown. Third, the unique apoptotic features shown for cholangiocytes are the ideal setting for the development of mitochondrial autoantigen presentation to the immune system through macrophages and AMA; thus, turning the non-traditional mitochondrial antigen into a traditional one. This article will review the current knowledge on PBC etiology and pathogenesis in light of the clonal selection theory developments. [ABSTRACT FROM AUTHOR]

Abstract: Immune mechanisms have been implicated in the pathogenesis of epilepsy. An increased prevalence of autoantibodies, as well as changes in serum immunoglobulin concentrations, has been reported in patients with epilepsy. The presence of unspecific antimitochondrial antibodies (AMAs) and their possible associations with other immunological markers were evaluated in a cohort of 1386 adult patients with epilepsy and population-based reference subjects. Unspecific AMAs were more frequent in epilepsy patients than in the reference group. Thirty-seven epilepsy patients (3.9%) and eleven control subjects (1.9%) had unspecific AMAs (RR 2.1, CI 1.05–4.1, P =0.03). These antibodies were associated with long duration of epilepsy and old age at the onset of epilepsy among patients with epilepsy. Their presence was independent of other immunological markers, comorbidity, and epilepsy medications. [Copyright &y& Elsevier]