Intrahepatic expression of the co-stimulatory molecules programmed death-1, and its ligands in autoimmune liver disease

Liver-infiltrating T cells play an essential role in the immunopathogenesis of autoimmune liver disease. Programmed death-1 (PD-1) and its ligands, B7-H1/PD-L1 and B7-DC/PD-L2, are new CD28-B7 family members that are involved in the regulation of immune responses. The ligation of PD-1 inhibits T-cell receptor-mediated T cell proliferation and cytokine production, and PD-1-deficient mice develop various organ-specific autoimmune diseases. To investigate the expressions of PD-1 and its ligands in autoimmune liver disease, in particular autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC), immunohistochemical analysis was performed. Liver biopsy specimens obtained from 17 patients with AIH and PBC were studied. PD-1 was expressed on more than half of the liver-infiltrating T cells within the portal tract. Some of the intrahepatic T cells expressed B7-H1 in patients with AIH and PBC. B7-H1 and B7-DC were mainly expressed on some Kupffer cells (KC) and liver sinusoidal endothelial cells (LSEC) within the sinusoids and their expression was upregulated in autoimmune liver disease. These results suggest that the interaction of PD-1 on T cells with increased expression of B7-H1 and B7-DC on KC and LSEC might be involved in the downregulation of autoreactive lymphocytes and result in the regulation of pathogenesis in autoimmune liver disease.     

Anti-asialoglycoprotein receptor autoantibodies,detected by a capture-immunoassay,are associated with autoimmune liver diseases

In autoimmune chronic active hepatitis (AIH) and primary biliary cirrhosis (PBC), various autoantibodies including anti-asialoglycoprotein receptor (ASGPR) antibodies have been found in patients' sera. We have previously developed a mouse monoclonal antibody against rat and human ASGPR. In this study, we developed a capture enzyme-linked immunosorbent assay (ELISA) for detection of anti-ASGPR antibodies using this monoclonal antibody and investigated the occurrence of anti-ASGPR antibodies in the sera of patients with various liver diseases. Serum samples were obtained from 123 patients with various liver diseases, including 21 patients with AIH and 40 patients with PBC. In this capture ELISA, the target antigen in the crude rat liver membrane extracts was captured on the ELISA wells by the ASGPR-specific mouse monoclonal antibody. Thus, the cumbersome process of antigen purification was rendered unnecessary. Using this capture ELISA, we detected the anti-ASGPR antibody in 67% of the patients with AIH, in 100% of the patients with PBC, and in 57% of the patients with acute hepatitis type A. However, the anti-ASGPR antibody was rarely detected in patients with other liver diseases such as primary sclerosing cholangitis and obstructive jaundice. Our findings suggest that this capture ELISA would be useful for the detection of anti-ASGPR antibodies in autoimmune liver diseases.     

A spectrum of histopathologic findings in autoimmune liver disease

We retrospectively studied 42 liver biopsy specimens from 39 patients who met serologic and histologic criteria of autoimmune liver diseases. We found 10 cases of overlap syndrome (OLS), 10 autoimmune cholangitis (AIC), 10 primary biliary cirrhosis (PBC), and 9 autoimmune hepatitis (AIH) type 1. The following results were obtained: (1) Granulomas and biliary duct lesions were more prominent in PBC and AIC than in OLS and AIH. (2) Bile duct loss was not observed in AIH cases. (3) Features of hepatocellular damage such as piecemeal necrosis, spotty lobular necrosis, and confluent necrosis, were much more prevalent in OLS and AIH than in PBC and AIC. (4) HLA-DR antigen expression by hepatocytes was more frequent in AIH and OLS, whereas the expression of the same antigen by the bile duct epithelium was more frequent in PBC and AIC. We conclude there is a morphologic spectrum in autoimmune liver diseases, in which PBC forms one end of the spectrum, AIH the other, OLS the middle but closer clinically and histologically to AIH than to PBC, and AIC, which seems to be an antimitochondrial antibody-negative subtype of PBC.     

Liver sinusoidal endothelial cells and acute non‐oxidative hepatic injury induced by Pseudomonas aeruginosa pyocyanin

The liver sinusoidal endothelial cell (LSEC) is damaged by many toxins, including oxidants and bacterial toxins. Any effect on LSECs of the Pseudomonas aeruginosa virulence factor, pyocyanin, may be relevant for systemic pseudomonal infections and liver transplantation. In this study, the effects of pyocyanin on in vivo rat livers and isolated LSECs were assessed using electron microscopy, immunohistochemistry and biochemistry. In particular, the effect on fenestrations, a crucial morphological aspect of LSECs was assessed. Pyocyanin treatment induced a dose‐dependent reduction in fenestrations in isolated LSECs. In the intact liver, intraportal injection of pyocyanin (11.9 μM in blood) was associated with a reduction in endothelial porosity from 3.4 ± 0.2% (n = 5) to 1.3 ± 0.1% (n = 7) within 30 min. There were decreases in both diameter and frequency of fenestrations in the intact endothelium. There was also a decrease in endothelial thickness from 175.8 ± 5.8 to 156.5 ± 4.0 nm, an endothelial pathology finding previously unreported. Hepatocyte ultrastructure, liver function tests and immunohistochemical markers of oxidative stress (3‐nitrotyrosine and malondialdehyde) were not affected. Pyocyanin induces significant ultrastructural changes in the LSEC in the absence of immunohistochemical evidence of oxidative stress or hepatocyte injury pointing to a novel mechanism for pyocyanin pathogenesis.     

The Hepatitic/Cholestatic "Overlap" Syndrome: An Italian Experience

Background: Patients with hepatitic and cholestatic autoimmune liver disease ("overlap syndrome") represent a diagnostic and therapeutic challenge. Aim: To evaluate the prevalence of the "hepatitic/cholestatic overlap" in a large series of consecutive patients with cholestatic autoimmune liver disease. Methods: We re-evaluated the diagnosis of 235 patients with autoimmune liver disease, including 70 with type 1 autoimmune hepatitis (AIH), 142 with primary biliary cirrhosis (PBC), and 23 with primary sclerosing cholangitis (PSC), using the revised International Autoimmune Hepatitis Group (IAIHG) scoring system. Anti-mitochondrial, anti-nuclear, anti-smooth muscle, anti-liver kidney microsomal type 1, anti-liver cytosol type 1, perinuclear anti-neutrophil nuclear and anti-soluble liver antigen antibodies were evaluated in each patient. Results: Ten patients (3 with a previous diagnosis of PBC and 7 of PSC) scored as "probable" or "definite" AIH. These patients did not have a specific autoantibody profile. Conclusions: Among patients with PBC, the occurrence of a PBC/AIH overlapping syndrome is rare (2.1%), whereas among patients with PSC an overlap between PSC and AIH is frequent (30.4%). Whether patients with the hepatitic/cholestatic overlap syndrome would benefit from a combination therapy with immunosuppression and ursodeoxycholic acid remains to be established.     

The hepatitic/cholestatic "overlap" syndrome: an Italian experience

BACKGROUND: Patients with hepatitic and cholestatic autoimmune liver disease ("overlap syndrome") represent a diagnostic and therapeutic challenge. AIM: To evaluate the prevalence of the "hepatitic/cholestatic overlap" in a large series of consecutive patients with cholestatic autoimmune liver disease. METHODS: We re-evaluated the diagnosis of 235 patients with autoimmune liver disease, including 70 with type 1 autoimmune hepatitis (AIH), 142 with primary biliary cirrhosis (PBC), and 23 with primary sclerosing cholangitis (PSC), using the revised International Autoimmune Hepatitis Group (IAIHG) scoring system. Anti-mitochondrial, anti-nuclear, anti-smooth muscle, anti-liver kidney microsomal type 1, anti-liver cytosol type 1, perinuclear anti-neutrophil nuclear and anti-soluble liver antigen antibodies were evaluated in each patient. RESULTS: Ten patients (3 with a previous diagnosis of PBC and 7 of PSC) scored as "probable" or "definite" AIH. These patients did not have a specific autoantibody profile. CONCLUSIONS: Among patients with PBC, the occurrence of a PBC/AIH overlapping syndrome is rare (2.1%), whereas among patients with PSC an overlap between PSC and AIH is frequent (30.4%). Whether patients with the hepatitic/cholestatic overlap syndrome would benefit from a combination therapy with immunosuppression and ursodeoxycholic acid remains to be established.     

自身免疫肝病患者抗中性粒细胞胞浆抗体的检测及临床意义

探讨抗中性粒细胞胞浆抗体(anti-neutrophil cytoplastic antibodies,ANCA)对自身免疫肝病的临床意义。应用间接免疫荧光法和斑点法检测149例自身免疫性肝病患者[自身免疫性肝炎(autoimmune hepatitis,AIH)患者57例,原发性胆汁性肝硬化(primary biliary cirrhosis,PBC)患者42例,不明原因肝损患者50例]的ANCA和抗可提取性核抗原抗体(extract-able nuclear antigen,ENA),进而用ELISA法分析60例ANCA阳性的自身免疫肝病患者的ANCA抗原谱。以200例健康献血员为正常对照。结果ANCA在AIH、PBC、不明原因肝损中的阳性率分别为81%、40%、30%,其中非典型性pANCA的阳性率依次为70%、40%、28%。AIH组与PBC组及AIH组与不明原因肝损组间非典型性pANCA的阳性率有显著性差异(P<0.01),但PBC组与不明原因肝损组间差异不显著(P>0.05)。各疾病组ANCA抗原谱如下:AIH组中,乳铁蛋白3%阳性,MPO 11%阳性,组织蛋白酶G和BPI的阳性率分别为11%、17%;PBC组中,弹性蛋白酶和组织蛋白酶G阳性率均为5%,BPI的阳性率为16%;不明原因肝损组中,BPI阳性率为17%。大多数自身免疫性肝病患者非典型性pANCA为阳性(28%~70%),且伴有特征性自身抗体。注重非典型性pANCA的检测对明确诊断自身免疫肝病及其分类有很大的帮助。     

Argininosuccinate lyase: a new autoantigen in liver disease

Anti-liver cytosol 1 autoantibody (LC1) characterizes a severe form of autoimmune hepatitis (AIH), staining the cytoplasm of periportal hepatocytes and targeting an unidentified 60-kD liver cytosolic antigen. To identify its target, we used high-titre anti-LCI⁺ sera from two patients with AIH to screen 18 cytoplasm enzymes with periportal location by double immunodiffusion (DDI). Both sera gave a broad precipitin line against human liver cytosol, suggesting that they may recognize two distinct antigens, a possibility confirmed by the appearance of two precipitin lines when DDI conditions were optimized (0.8% agarose and 3% polyethylene glycol (PEG)). Experiments by DDI and Western blot (WB) identified a liver cytosolic autoantigen of 50 kD, different from LC1, giving a line of identity with argininosuccinate lyase (ASL). Reactivity to ASL was then investigated by DDI and WB in 57 patients with AIH, 17 with primary biliary cirrhosis (PBC), 15 with chronic hepatitis B virus (HBV) infection, 13 with α_l-antitrypsin deficiency, 17 with Wilson's disease, 18 with extrahepatic autoimmune disorders, and in 48 healthy controls. Anti-ASL was found in 16% of AIH and 23% of PBC patients by DDI and in 14% of AIH, 23% of PBC and 20% of HBV patients by WB. No argininosuccinate was present in the urine of four anti-ASL⁺ patients tested, excluding an inhibition of enzymatic activity by anti-ASL. The addition of anti-ASL⁺ serum to human fibroblast cultures induced a significant increase in ASL activity. ASL is a new autoantigen in liver disease and its clinical relevance warrants further investigation.     

Liver sinusoidal endothelial cells induce immunosuppressive IL‐10‐producing Th1 cells via the Notch pathway

Under homeostasis, liver sinusoidal endothelial cells (LSECs) shift intrahepatic T‐cell responses towards tolerance. However, the role of LSECs in the regulation of T‐cell‐induced liver inflammation is less clear. Here, we studied the capacity of LSECs to modulate pro‐inflammatory Th1‐cell differentiation in mice. Using in vitro co‐culture systems and subsequent cytokine analysis, we showed that LSECs induced high amounts of the anti‐inflammatory cytokine IL‐10 in developing Th1 cells. These LSEC‐stimulated Th1 cells had no pro‐inflammatory capacity in vivo but instead actively suppressed an inflammatory Th1‐cell‐induced delayed‐type hypersensitivity reaction. Blockage of IL‐10 signaling in vivo inhibited immunosuppressive activity of LSEC‐stimulated Th1 cells. We identified the Notch pathway as a mechanism how LSECs trigger IL‐10 expression in Th1 cells. LSECs expressed high levels of the Delta‐like and Jagged family of Notch ligands and induced expression of the Notch target genes hes‐1 and deltex‐1 in Th1 cells. Blockade of Notch signaling selectively inhibited IL‐10 induction in Th1 cells by LSECs. Our findings suggest that LSEC‐induced IL‐10 expression in Th1 cells via the Notch pathway may contribute to the control of hepatic inflammatory immune responses by induction of a self‐regulatory mechanism in pro‐inflammatory Th1 cells.     

Detection of anti-nuclear antibodies in liver diseases by indirect immunofluorescence method and enzyme-linked immunosorbent assay]

Detection of anti-nuclear antibodies (ANA) is essential for diagnosing autoimmune diseases including autoimmune liver diseases. An indirect immunofluorescence (IIF) method with a cell line (HEp-2) derived from human laryngeal carcinoma has been used as a standard substrate. Recently, an enzyme-linked immunosorbent assay (ELISA) using multiple solid-phase antigens has been developed. We assayed sera from 272 cases of chronic liver diseases, 91 cases of healthy subjects and studied clinical significance of ANA. The sensitivity of IIF method in detection of ANA (fluorescence-ANA: FANA) and that of ELISA (ELISA-ANA: EANA) were 19.2% and 17.3% in chronic hepatitis B (CH-B), 16.7% and 17.3% in chronic hepatitis C (CH-C), 84.2% and 50.9% in primary biliary cirrhosis (PBC), 100% and 85.7% in autoimmune hepatitis (AIH) and 15.4% and 18.7% in healthy subjects. The sensitivity of EANA was considerably lower than that of FANA in PBC and AIH, but the sensitivity was the same in CH-C, CH-B, and healthy subjects. Because the solid-phase target antigens do not include nuclear antigen components recognized only by patients with PBC or AIH, ELISA can not detect all the species of ANA. This accounts for the low sensitivity of EANA in PBC and AIH. In conclusion, the current EANA is useful for screening of ANA, but FANA should be performed when PBC or AIH is suspected.     

Increase of chemokine interferon-inducible protein-10 (IP-10) in the serum of patients with autoimmune liver diseases and increase of its mRNA expression in hepatocytes

To clarify the role of IP-10 in autoimmune liver diseases, we studied the serum levels of IP-10 in 14 patients with autoimmune hepatitis (AIH), 23 patients with primary biliary cirrhosis (PBC), and 65 patients with chronic viral hepatitis (20 type B and 45 type C). The hepatic expression of IP-10 mRNA and the correlation between the serum levels of IP-10 and clinical parameters were also evaluated. In addition to 20 healthy controls, 16 rheumatoid arthritis (RA) patients were included as an extrahepatic inflammatory disease. The serum level of IP-10 was significantly (P < 0.02) higher in patients with AIH, PBC, and chronic hepatitis B and C than in healthy controls, and it was significantly correlated (P < 0.05) with the serum levels of aspartate aminotransferase and alanine aminotransferase in patients with AIH, PBC, and chronic hepatitis B and C. The serum level of IP-10 was not elevated in RA patients. After successful treatment of AIH and chronic hepatitis C, the serum level of IP-10 decreased to the same level as in healthy volunteers. As we previously showed in cases with chronic hepatitis B or C, in situ hybridization in both AIH and PBC cases demonstrated the expression of IP-10 mRNA in hepatocytes around focal or lobular necrosis surrounded by infiltrating mononuclear cells, whereas IP-10 mRNA was not expressed in areas around the damaged bile ducts in PBC cases. The present results suggest that IP-10 is specifically produced by hepatocytes in inflammatory areas irrespective of the aetiology of hepatitis, and that IP-10 may help to recruit T cells to the hepatic lesions in autoimmune liver diseases as well as in chronic viral hepatitis.     

Autoimmune hepatitis in primary Sjogren's syndrome: pathological study of the livers and labial salivary glands in 17 patients with primary Sjogren's syndrome

Although primary Sjogren's syndrome (pSS) is an autoimmune exocrinopathy, the involvement of liver has been reported. Because no study focusing on autoimmune hepatitis (AIH) in pSS has been published, the purpose of the present study was to perform a clinical and histological examination of the liver, focusing on AIH, in 17 pSS patients. The patients had liver enzyme abnormalities without hepatitis virus infection. In all cases, biopsied livers were examined, and in 10 cases biopsied labial salivary glands were also examined histologically. Based on the authors' diagnostic criteria for AIH in pSS, the liver diseases consisted of AIH (eight cases, 47%), primary biliary cirrhosis (PBC; six cases, 35%), non-specified chronic hepatitis (two cases, 12%) and acute hepatitis (one case, 6%). Lymphoplasmacytic infiltrate, with predominancy of CD3(+) T cells, was noted in both the liver and salivary glands in the patients with AIH. The patients with AIH with severe interface hepatitis had a good response to immunosuppressive therapy. The comparison of liver histology between the PBC with pSS group and the PBC without pSS group showed that the incidence of lymphoid non-suppurative cholangitis was higher in PBC with pSS. In conclusion, the present study offers new information on the relatively common occurrence, diagnostic criteria and treatment effects of AIH in pSS.     

In situ mass spectrometry of autoimmune liver diseases

Primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH) are the major forms of autoimmune liver diseases each characterized by the destruction of a specific liver cell type and the presence of differing auto-antibodies. We took a proteomic approach utilizing in situ matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) to obtain profiles directly from liver samples of patients with PBC, PSC, AIH and controls. The ability to precisely localize the region for acquisition of MALDI MS allowed us to obtain profiles from bile ducts, inflammatory infiltrates and hepatocytes from each biopsy sample. Analysis tools developed to identify peaks and compare peaks across diseases and cell types were used to develop models to classify the samples. Using an initial set of testing samples from PBC patients and controls, we identified unique peaks present in bile ducts, inflammatory infiltrates and hepatocytes that could classify samples in a validation cohort with 88-91% accuracy. Interestingly, profiles of PSC and AIH did not differ significantly from PBC. Identification of proteins in these peaks may represent novel autoantigens or effector molecules. These findings illustrate the potential of a proteomic approach to autoimmune diseases with in situ MALDI MS.     

The role of complement activation in autoimmune liver disease

IntroductionThe complement system, an essential part of the innate immune system, is involved in various autoimmune diseases. Activation of the complement system by autoantibodies results in immune activation and tissue damage. At the moment little is known about the role of the complement system in autoimmune liver disease, including primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH). Since inhibition of the complement system is currently being tested in several autoimmune diseases as a therapeutic option, its role in autoimmune liver disease requires further clarification.MethodsA review of the literature was performed on studies investigating complement activation in PBC, PSC and AIH. Since data on AIH were lacking immunohistochemical staining for IgG, C1q, C3d, C4d and C5b9 was performed on liver tissue of nine AIH patients, two healthy controls and one positive control (acute liver failure caused by paracetamol intoxication).ResultsImmunohistochemical analysis in AIH revealed increased production of C3 and C4 by hepatocytes. Despite a strong staining for IgG in the immune infiltrate in AIH, C3d, C4d and C5b9 deposition was only present in one AIH patient and the deposition was restricted to the interface between portal tracts and liver parenchyma. No deposition was found in all other AIH patients or healthy controls.Literature review showed raised plasma C3 and C4 levels in AIH, PBC and PSC patients compared to healthy controls. For PBC and PSC no complement depositions at the bile ducts were reported.Conclusion and discussionAlthough complement is involved in various autoimmune diseases, the role of complement in autoimmune liver disease seems limited. Therefore it is unlikely that complement inhibition will become a novel treatment option for these diseases.     

Portal tract eosinophils and hepatocyte cytokeratin 7 immunoreactivity helps distinguish early-stage, mildly active primary biliary cirrhosis and autoimmune hepatitis.

We studied nondiagnostic liver biopsy specimens from 20 patients with definite primary biliary cirrhosis (PBC) and 18 with definite autoimmune hepatitis (AIH) to identify distinguishing features. All patients had early-stage disease; biopsy specimens were devoid of granulomas or diagnostic features of PBC or AIH. Diagnoses were based on serologic and clinical variables. Sixteen specimens from each group were immunostained with cytokeratin 7. The density of portal tract eosinophils and number with cytokeratin 7-reactive periportal hepatocytes were quantified. Sixteen of 18 patients with AIH and 13 of 20 with PBC had no or minimal bile duct injury. Histologic activity index scores were 5.8 in AIH and 5.7 in PBC. The mean portal eosinophil score was greater in PBC than in AIH. Cytokeratin 7 identified many central bile ducts that were obscured by portal inflammation. The mean periportal cytokeratin 7-reactive hepatocyte score was greater in PBC than in AIH. Portal eosinophils and cytokeratin 7 reactivity in periportal hepatocytes are supportive of PBC rather than AIH. No morphologic features were supportive of AIH. Cytokeratin 7 reactivity in periportal hepatocytes may be an early response to PBC-induced biliary obstruction in other regions of the liver.     

IgA Anti-b2GPI Antibodies in Patients with Autoimmune Liver Diseases

INTRODUCTION: Recently, we reported a high prevalence of immunoglobulin G and/or immunoglobulin M anticardiolipin antibodies (aCL) in patients with autoimmune liver diseases, namely, autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC), which were independent of the respective isotypes of antibodies against beta2-glycoprotein I (anti-b2GPI). Immunoglobulin A (IgA) aCL and IgA anti-b2GPI are the least studied of the three specific isotypes either in antiphospholipid syndrome (APS) or in other conditions. METHODS: Therefore, we investigated the prevalence and clinical significance of IgA anti-b2GPI and IgA aCL by enzyme-linked immunosorbent assays in another set of Caucasian patients with autoimmune liver diseases (59 AIH, 96 PBC, and 37 PSC). The disease controls group consisted of 50 hepatitis C virus (HCV) patients, 50 hepatitis B virus (HBV), 30 alcoholic liver disease (ALD), 30 non-alcoholic steatohepatitis (NASH), and 110 healthy controls. RESULTS AND DISCUSSION: IgA anti-b2GPI prevalence was higher in AIH (50.8%) compared to PBC (p = 0.005), PSC (p = 0.008), NASH (p = 0.004), ALD (p = 0.01), and HCV (p = 0.002). The titers were also significantly higher in AIH compared to any other group of the study. IgA aCL prevalence was higher in AIH (33.9%) compared to PBC (p = 0.005), PSC (p = 0.014), NASH (p = 0.001), ALD (p = 0.004), and HCV (p < 0.001). IgA anti-b2GPI or IgA aCL were not associated with APS features in patients with liver autoimmunity. Of note, IgA anti-b2GPI and IgA aCL were associated with clinical and biochemical markers of disease severity in AIH and PBC. We demonstrated a high prevalence and high titers of IgA anti-b2GPI in patients with AIH compared to any other liver disease of the study. CONCLUSION: IgA anti-b2GPI and IgA aCL were associated with the severity and biochemical activity of AIH and PBC, but long-term prospective studies are needed to address whether this new finding is of clinical importance in AIH and PBC patients.     

Do Autoantibodies Predict Autoimmune Liver Disease in Primary Sjögren's Syndrome? Data of 180 Patients upon a 5 Year Follow‐Up

Objective: To evaluate the clinical value of autoantibodies as serological markers to predict autoimmune liver diseases in primary Sjögren's syndrome (SS). Materials and methods: 180 patients who met the European diagnostic criteria for SS but without a history of liver disease were studied upon a 5 year follow‐up. Sera taken at enrolment were evaluated by immunofluorescence analysis (IF‐AMA) on rat liver, stomach and kidney sections, enzyme‐linked immunosorbent assay using rat mitochondrial, microsomal and soluble liver antigens and Western blot (WB) analysis using rat mitochondrial antigens. Results: At presentation, 152 (84%) sera had autoantibodies. Antinuclear antibodies (ANA) were expressed in 58% of patients and displayed three distinct patterns (speckled, homogenous and anticentromere). Smooth muscle autoantibodies (SMAs) and parietal cell autoantibodies were found in 39 and 4.5% of patients, respectively. Three patients presented antimitochondrial antibodies by IF‐AMA, and two of them developed symptomatic primary biliary cirrhosis (PBC). Two patients without IF‐AMA and without evidence of cholestasis had PBC‐specific AMA (anti‐PDC–E2 and anti‐BCKADC–E2). However, these two patients and the third IF‐AMA‐positive woman remained free from symptoms and biochemical signs of PBC. Autoimmune hepatitis (AIH) (n = 2), ‘overlap syndrome’ of AIH and chronic hepatitis C (n = 1) and autoimmune cholangiopathy (AIC) (n = 1) were diagnosed in four patients. Conclusions: Patients with IF‐AMA usually develop symptomatic PBC upon a 5 year follow‐up. Our findings support the idea that patients without IF‐AMA, who express PBC‐specific AMA, are in early, asymptomatic stage of the disease. High‐titre SMA and IF‐AMA are the most specific indicators for AIH and PBC.     

自身免疫性肝炎合并自身免疫性疾病的特征研究

目的 比较自身免疫性肝炎（AIH）合并原发性胆汁性胆管炎（PBC）或部分肝外自身免疫性疾病（autoimmune disease）患者与单纯AIH患者临床特点及并发症,为改善AIH患者的诊治提供参考。方法 收集1999年8月~2019年8月我院收治的AIH患者149例,根据合并症分为无合并病的AIH组（68例）、AIH合并PBC组（AIH-PBC 组,41例）及AIH合并肝外自身免疫性疾病组（AIH-肝外组,40例）,比较三组临床特点、并发症、肝纤维化/肝硬化进展情况。结果 ①AIH-PBC 组及AIH-肝外组年龄低于AIH组,差异有统计学意义（P＜0.05）;三组性别比较,差异无统计学意义（P＞0.05）。②三组共有的临床症状为瘙痒、黄疸、乏力、食欲不振及腹部不适,其中AIH-PBC组瘙痒症状患者多于AIH组、AIH-肝外组,差异有统计学意义（P＜0.05）;三组黄疸、乏力、食欲不振及腹部不适比较,差异无统计学意义（P＞0.05）。③AIH-PBC 组ALT低于AIH组及AIH-肝外组,ALP、GGT高于AIH组及AIH-肝外组,差异有统计学意义（P＜0.05）;AIH-肝外组的AST、DBIL高于AIH组及AIH-PBC 组,差异有统计学意义（P＜0.05）;AIH-肝外组IgG水平高于AIH组及AIH-PBC 组,差异有统计学意义（P＜0.05）。④三组ANA、ASMA、SLA、LKM-1阳性率比较,差异无统计学意义（P＞0.05）;AIH-PBC组AMA、AMA-M2 阳性率高于AIH组、AIH-肝外组,差异有统计学意义（P＜0.05）。⑤三组均以界面性肝炎和淋巴细胞浸润表现居多,其中AIH-PBC组胆管病变、胆汁淤积高于AIH组,差异有统计学意义（P＜0.05）。⑥三组并发症主要包括食管胃底静脉曲张/破裂出血、腹水、肝性脑病、肝癌、肝移植,组间比较,差异无统计学意义（P＞0.05）。⑦三组肝纤维化/肝硬化发生率比较,差异无统计学意义（P＞0.05）;但AIH-PBC组2~5年肝纤维化/肝硬化进展率高于AIH组及AIH-肝外组,差异有统计学意义（P＜0.05）。结论 合并PBC的AIH患者比单纯AIH患者诊断年龄早,肝脏炎症反应轻、胆管病变重;比AIH及合并肝外自身免疫性疾病更易出现瘙痒、胆汁淤积更重、胆管损伤更严重,且肝纤维化/肝硬化速度更快。AMA、AMA-M2可作为AIH合并PBC的鉴别指标。另外,AIH合并肝外自身免疫性疾病常存在肝功能损害,IgG对其具有提示意义。     

Autoantibodies associated with primary biliary cholangitis are common among patients with systemic lupus erythematosus even in the absence of elevated liver enzymes

Knowledge of concomitant autoimmune liver diseases (AILD) is more detailed in primary Sjögren’s syndrome (pSS) compared to systemic lupus erythematosus (SLE). Herein, the prevalence of autoantibodies associated with autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) was investigated in stored sera from patients with SLE (n = 280) and pSS (n = 114). Antibodies against mitochondria (AMA), liver–kidney microsomal (LKM) antigen, smooth muscle (SMA) and anti‐nuclear antibodies (ANA) were analysed with immunofluorescence microscopy. In addition, AILD‐associated autoantibodies were tested with immunoblot. Prior to sampling, eight SLE (2·9%) and three pSS (2·6%) cases were diagnosed with AILD. Among SLE‐cases without known AILD (n = 272), 26 (9·6%) had PBC‐associated autoantibodies, 15 (5·5%) AIH‐associated autoantibodies (excluding ANA) and one serological overlap. Most subjects with PBC‐associated autoantibodies had liver enzymes within reference limits (22 of 27, 81%) or mild laboratory cholestasis (two of 27, 7·4%), while one fulfilled the diagnostic PBC‐criteria. AMA‐M2 detected by immunoblot was the most common PBC‐associated autoantibody in SLE (20 of 272, 7·4%). The prevalence of SMA (4·4%) was comparable with a healthy reference population, but associated with elevated liver enzymes in four of 12 (25%), none meeting AIH‐criteria. The patient with combined AIH/PBC‐serology had liver enzymes within reference limits. Among pSS cases without known AILD (n = 111), nine (8·1%) had PBC‐associated, 12 (10·8%) AIH‐associated autoantibodies and two overlapped. PBC‐associated autoantibodies were found as frequently in SLE as in pSS but were, with few exceptions, not associated with laboratory signs of liver disease. Overall, AILD‐associated autoantibodies were predominantly detected by immunoblot and no significant difference in liver enzymes was found between AILD autoantibody‐negative and ‐positive patients.     

Endotheliopathy of liver sinusoidal endothelial cells in liver disease

Liver is the largest solid organ in the abdominal cavity, with sinusoid occupying about half of its volume. Under liver disease, hemodynamics in the liver tissue dynamically change, resulting in injury to liver sinusoidal endothelial cells (LSECs). We discuss the injury of LSECs in liver diseases in this article. Generally, in noninflamed tissues, vascular endothelial cells maintain quiescence of circulating leukocytes, and unnecessary blood clotting is inhibited by multiple antithrombotic factors produced by the endothelial cells. In the setting of inflammation, injured endothelial cells lose these functions, defined as inflammatory endotheliopathy. In chronic hepatitis C, inflammatory endotheliopathy in LSECs contributes to platelet accumulation in the liver tissue, and the improvement of thrombocytopenia by splenectomy is attenuated in cases with severe hepatic inflammation. In COVID-19, LSEC endotheliopathy induced by interleukin (IL)-6 trans-signaling promotes neutrophil accumulation and platelet microthrombosis in the liver sinusoids, resulting in liver injury. IL-6 trans-signaling promotes the expression of intercellular adhesion molecule-1, chemokine (C-X-C motif) ligand (CXCL1), and CXCL2, which are the neutrophil chemotactic mediators, and P-selectin, E-selectin, and von Willebrand factor, which are involved in platelet adhesion to endothelial cells, in LSECs. Restoring LSECs function is important for ameliorating liver injury. Prevention of endotheliopathy is a potential therapeutic strategy in liver disease.