Autoantibodies in liver disease: important clues for the diagnosis, disease activity and prognosis

Histology and clinical correlations in autoimmune hepatitis, primary biliary cholangitis, and autoimmune hepatitis-primary biliary cholangitis overlap syndrome

OBJECTIVES

The diagnosis of autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and AIH-PBC overlap syndrome (OS) relies on their histologic features and clinical findings. In this study, we aimed to identify specific morphologic features of these diseases and evaluate their clinical correlation.

METHODS

We included initial biopsies from untreated patients with AIH (n = 14), PBC (n = 10), and OS (n = 7). Histologic features of the portal tract, portal-lobular interface, and hepatic lobule, fibrosis, as well as clinical data including serology, autoantibodies, treatment, and prognosis were reviewed and analyzed.

RESULTS

Our results showed that several histologic features differed significantly between AIH and PBC (p < 0.05). Among these features, OS cases were more likely to present with bile duct-centered processes (presence of bile duct damage while absence of inflammation gradient from bile duct to interface, plasma cell cluster and pericentral inflammation) unlike those seen in AIH (p < 0.05), and interface-centered processes (unequivocal interface hepatitis, ductular reaction, and periportal fibrosis) which were not seen in PBC (p < 0.05). We observed a significant correlation between transaminase levels and lobular inflammation, including numbers of lymphocyte, plasma cell and eosinophil. Our study also found that anti-smooth muscle antibody positivity was associated with interface hepatitis (p < 0.01), while antimitochondrial antibody positivity was associated with duct damage (including ductopenia) and granulomas (p < 0.05).

CONCLUSION

Our results highlight distinctive morphological features between AIH and PBC. The possibility of overlap syndrome should be considered when encountering AIH with bile duct-centered processes or PBC with interface-centered processes in morphology and correlation with autoantibodies.

Autoantibody Positivity Has No Impact on Histological Parameters in Nonalcoholic Fatty Liver Diseases

Objectives

Previous reports on association of autoantibodies with histological severity in nonalcoholic fatty liver disease (NAFLD) have revealed inconsistent results. Therefore, this study was undertaken to find the impact of autoantibodies on histological severity of NAFLD.

Methods

All cases with histological diagnosis of NAFLD during January 2016 to January 2021 were included in the study. Laboratory parameters were recorded, and histological assessment was done. The positivity of autoimmune markers was defined as presence of either antinuclear antibody (ANA; titer >1:80), anti-smooth muscle antibodies (ASMA), or anti-liver-kidney-microsomal antibodies (LKM-1; titer >1:40). Serum levels of CK18 - M30 and PIIINP were evaluated to assess the subtle changes in necroinflammatory activity and fibrosis in the liver.

Results

Autoantibodies were present in 281/683 (41.1%, 95% CI 37.4-44.9) patients. ANA, ASMA, ANA + ASMA was seen in 20.9% (95% CI 17.9-24.2); 14.5% (95% CI 11.9-17.4); and 5.7% (95% CI 4.1-7.7) cases, respectively. No significant difference was noted between the two groups in terms of age and metabolic tests. No significant difference was noted in the histological parameters between groups with autoantibodies positivity and no-positivity. Mean value of CK18-M30 between cases with negative autoantibody; ANA positivity; ASMA positivity; and combined positivity of autoantibody were 178.2 ± 81.8, 161.6 ± 63.7, 153.2 ± 70.3 and 169.8 ± 42.9, respectively (P = 0.57). However, CK18-M30 and PIIINP showed a rising trend with NAFL, NASH, NASH + AIH (P < 0.001).

Conclusions

Autoantibodies noted in 41% NAFLD cases. No significant necroinflammatory activity or fibrosis associated with presence of antibodies in NAFLD cases. However, CK-18-M30 showed a rising trend from NAFL to NASH to NASH + AIH.

Myositis autoantibodies detected by line blot immunoassay: clinical associations and correlation with antibody signal intensity

The aim of this study is to assess the relationship between myositis specific (MSA) and myositis associated (MAA) antibodies and diagnosis (including idiopathic inflammatory myopathies [IIM] and other systemic autoimmune diseases [SAID]), and to explore the impact of antibody signal intensity in diagnostic accuracy. We retrospectively reviewed all the serum samples obtained from patients tested for MSA/MAA by line immunoassay (LIA) between 01/01/2018 and 31/12/2020 in Ramón y Cajal University Hospital (Spain). Clinical true positive (CTP) MSAs and MAAs were defined as those patients with IIM or SAID with phenotypes expected of that MSA/MAA. Patients who did not have a phenotype compatible with that antibody were classified as clinical false positive (CFP). One hundred and thirty positive samples were analysed. Forty-six patients (33.38%) were classified as IIM, forty-two (32.3%) as SAID and forty-two (32.3%) as non-IIM/SAID. Among these 130 patients, 164 MSA/MAA were detected. Eighty-five (51.8%) positive MSA/MAA were classified as CTP, and seventy-nine (48.2%) as CFP. Strongly positive antibodies were more frequently CTP (35/47, 74.5%) than weak positives (54/68, 36.8%), (p ˂ 0.001). Antibodies classified as CTP had a higher signal intensity than CFP (36.77 AU vs 20.00 AU, CI95% 7.79-22.09, p ˂ 0.001). The probability of a CFP was associated to negative ANA, low ANA titer, and multiple positive MSA/MAA (p ˂ 0.001). In this study, we confirmed that CFP results using LIA are frequent, and are associated with low signal intensity MSA/MAA, negative ANA, lower titer ANA, and with multiple positive samples.

Liver kidney microsome antibodies. Analysis of a laboratory series

Objectives

The objectives were to characterize the liver kidney microsome (LKM) antibody profile of a 14-month-old girl with autoimmune hepatitis and analyze the laboratory prevalence of LKM positivity.

Design and methods

This is retrospective analysis of the LKM antibody immunofluorescence tests performed by the Immunology Laboratory of Johns Hopkins Hospital from September 8, 2020 to July 31, 2022. LKM positive sera were also tested by an ELISA for LKM1 antibodies, which recognize the cytochrome P450 2D6 antigen. In silico analysis of 2D6 mRNA expression across anatomical sites was performed using Bgee and GTEx Portal databases.

Results

Of the total of 1598 patients (893 F, 705 M, ages 0.8-94 years) tested for LKM antibodies, 3 were positive, yielding a 0.2% period prevalence. The clinical diagnosis was autoimmune hepatitis in the index case, acute viral hepatitis in a 3-yo male, and hepatocellular carcinoma in a 54-yo male. LKM antibodies yielded the classical homogenous staining pattern in the liver cytosol and proximal kidney tubular cells. The first two patients were also positive for LKM1 antibodies, whereas the third was negative. 2D6 mRNA was expressed highly in the liver, moderately in the duodenum, and minimally in other tissues.

Conclusions

Overall, LKM antibodies are rare. They contribute to establish a diagnosis of autoimmune hepatitis, although they are also found in other liver diseases. The cytochrome P450 2D6 is one of the antigens recognized by LKM antibodies, but other antigens are likely targeted considering that 2D6 is minimally expressed in the kidney and yet LKM antibodies bind to kidney tubuli.

Anti-F-Actin Antibody Positivity on Indirect Immunofluorescence Assay Following Chinese and Alternative Medicine Therapy: A Case Report

Immunofluorescence on human epithelial type 2 cells is the standard screening assay for the detection of antinuclear antibodies (ANA). Cytoplasmic speckled patterns are a common finding. However, the less commonly reported ones include the cytoplasmic fibrillar patterns on indirect immunofluorescence technique (IIFT). The cytoplasmic fibrillar patterns include the cytoplasmic linear (AC-15), cytoplasmic filamentous (AC-16), and cytoplasmic segmental (AC-17). We report a case of cytoplasmic linear (F-actin) detected through IIFT during ANA screening in a 77-year-old man and later reconfirmed on liver mosaic biochip through IIFT on vascular smooth muscle substrate (VSM-47) without features suggestive of anti-smooth muscle antibody involvement post-complementary and alternative medicine therapy initiation.

Autoantibodies: are they a clue for liver diseases?

Introduction

Autoantibody testing has contributed to both biological and clinical insights in managing patients with liver disease. These autoantibodies often have clinical value for the diagnosis, disease activity and/or prognosis.

Aim of the study

We aimed to investigate the potential application of auto-antibodies in different etiologies of non-autoimmune liver diseases.

Material and methods

This study was conducted on 53 infants and children with chronic liver diseases. The patients were subjected to clinical history and examination, laboratory investigations and abdominal ultrasound. Serum of all infants and children was tested for measurement of antiprothrombin antibody and anti-b2-glycoprotein I (ab2GPI) and anticardiolipin (ACL) auto-antibodies using a fully-automated enzyme linked immunosorbent assay (ELISA) system.

Results

The mean age of the infants with cholestatic liver diseases was significantly lower than those with metabolic liver diseases, hepatitis C virus (HCV) and vascular liver diseases (p < 0.05). The gender distribution was proportionate in all groups (p = 0.703). Autoantibodies showed significant variations among different etiologies of chronic liver diseases. he incidence of ab2GPI and ACL was significantly increased in both HCV (94.7% and 78.9%, respectively) and vascular liver diseases patients (90.9% and 72.7%, respectively) (p < 0.05). Antiprothrombin antibodies were found in 81.8% of vascular liver disease patients. Interestingly, all types of autoantibodies were deficient in cholestatic and metabolic liver diseases.

Conclusions

Testing for liver-related autoantibodies should be included in the workup of patients with chronic liver diseases. Further studies are needed to explain the cause-effect association of ACL, ab2GPI and antiprothrombin with chronic HCV and vascular liver diseases.

Regulation of Progression and Resolution of Liver Fibrosis by Immune Cells

The excessive accumulation of extracellular matrix proteins results in fibrosis-a condition implicated in several diseased conditions, such as nonalcoholic steatohepatitis, viral hepatitis, and autoimmune hepatitis. Despite its prevalence, direct and effective treatments for fibrosis are lacking, warranting the development of better therapeutic strategies. Accumulating evidence has shown that liver fibrosis-a condition previously considered irreversible-is reversible in specific conditions. Immune cells residing in or infiltrating the liver (e.g., macrophages) are crucial in the pathogenesis of fibrosis. Given this background, the roles and action mechanisms of various immune cells and their subsets in the progression and recovery of liver fibrosis, particularly concerning nonalcoholic steatohepatitis, are discussed in this review. Furthermore, the development of better therapeutic strategies based on stage-specific properties and using advanced techniques as well as the mechanisms underlying recovery are elaborated. In conclusion, we consider the review comprehensively provides the present achievements and future possibilities revolving around fibrosis treatment.

Seronegative autoimmune diseases: A challenging diagnosis

Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.

Intracellular virus sensor MDA5 mutation develops autoimmune myocarditis and nephritis

Mutations in IFIH1 gene encoding viral RNA sensor MDA5 have been reported responsible for many interferonopathies, including Aicardi-Goutières syndrome (AGS) and monogenic lupus, however, the pathological link between IFIH1 mutations and various autoimmune symptoms remains unclear. Here, we generated transgenic mice expressing human MDA5 R779H mutant (R779H Tg), reported in AGS and monogenic lupus patient. Mice spontaneously developed myocarditis and nephritis with upregulation of type I IFNs in the major organs. R779H Tg Mavs-/- and R779H Tg Ifnar-/- showed no phenotypes, indicating direct MDA5-signaling pathway involvement. Rag-2 deficiency and bone marrow cells transfer from wild type to adult mice did not prevent myocarditis development, while mice with cardiomyocyte-specific expression of hMDA5 R779H showed cardiomegaly and high expression of inflammatory cytokines. Taken together, our study clarifies that type I IFNs production and chemokines from cardiomyocytes starts in neonatal period and is critical for the development of myocarditis. Activated lymphocytes and auto-antibodies exacerbate the pathogenesis but are dispensable for the onset.

Chronic Liver Disease: A Mimic of Systemic Lupus Erythematosus

Humoral immune responses can produce autoantibodies against self-cellular proteins and nucleic acids without the presence of autoimmune diseases. Numerous kinds of autoantibodies are detected in liver diseases such as viral hepatitis, alcoholic liver disease (ALD), and nonalcoholic fatty liver disease (NAFLD), where their production could be secondary to hepatocellular inflammation and necrosis. Hence, the presence of an autoantibody does not necessarily indicate the presence of autoimmune disease; nor does it predict its severity and potential response to therapy. In literature, the spectrum and methods of diagnosis of liver disease in lupus are well described. However, chronic liver disease can manifest with signs similar to those in lupus, and it is important to recognize that autoantibodies in patients with chronic liver disease can be seen without the presence of autoimmune rheumatic disease. In this report, we discuss a very interesting case of a middle-aged female with a history of ALD presenting with calciphylaxis, thrombocytopenia, hypocomplementemia, and positive serologies, but without any clinical evidence of autoimmune rheumatic disease.

Approach to the patient with acute severe autoimmune hepatitis

Autoimmune hepatitis is associated with varied clinical presentations and natural history, as well as somewhat unpredictable treatment responses. Understanding how to stratify patients who require further escalation of therapy will help clinicians manage these patients. The presentation of acute severe autoimmune hepatitis (AS-AIH) is relatively uncommon, although its prevalence is potentially greater than currently perceived. Previous studies consist of small retrospective single-centre series and are not directly comparable due to the diversity of presentations, disease definitions and non-standardised treatment regimens. We define AS-AIH as those who present acutely with AIH and are icteric with an international normalised ratio ≥1.5 and no evidence of hepatic encephalopathy. Those with hepatic encephalopathy should be defined as having AS-AIH with acute liver failure. In this review, we provide a structured practical approach for diagnosing and managing this unique group of patients.

Autoimmune Hepatitis-Immunologically Triggered Liver Pathogenesis-Diagnostic and Therapeutic Strategies

Autoimmune hepatitis (AIH) is a severe liver disease that arises in genetically predisposed male and female individuals worldwide. Diagnosis of AIH is made clinically applying diagnostic scores; however, the heterotopic disease phenotype often makes a rapid determination of disease challenging. AIH responds favorably to steroids and pharmacologic immunosuppression, and liver transplantation is only necessary in cases with acute liver failure or end-stage liver cirrhosis. Recurrence or development of de novo AIH after transplantation is possible, and treatment is similar to standard AIH therapy. Current experimental investigations of T cell-mediated autoimmune pathways and analysis of changes within the intestinal microbiome might advance our knowledge on the pathogenesis of AIH and trigger a spark of hope for novel therapeutic strategies.

Autoantibody profiles in autoimmune hepatitis and chronic hepatitis C identifies similarities in patients with severe disease

AIM

To determine how the auto-antibodies (Abs) profiles overlap in chronic hepatitis C infection (CHC) and autoimmune hepatitis (AIH) and correlate to liver disease.

METHODS

Levels of antinuclear Ab, smooth muscle antibody (SMA) and liver/kidney microsomal-1 (LKM-1) Ab and markers of liver damage were determined in the sera of 50 patients with CHC infection, 20 AIH patients and 20 healthy controls using enzyme linked immunosorbent assay and other immune assays.

RESULTS

We found that AIH patients had more severe liver disease as determined by elevation of total IgG, alkaline phosphatase, total serum bilirubin and serum transaminases and significantly higher prevalence of the three non-organ-specific autoantibodies (auto-Abs) than CHC patients. Antinuclear Ab, SMA and LKM-1 Ab were also present in 36% of CHC patients and related to disease severity. CHC cases positive for auto-Abs were directly comparable to AIH in respect of most markers of liver damage and total IgG. These cases had longer disease duration compared with auto-Ab negative cases, but there was no difference in gender, age or viral load. KLM-1⁺ Ab CHC cases showed best overlap with AIH.

CONCLUSION

Auto-Ab levels in CHC may be important markers of disease severity and positive cases have a disease similar to AIH. Auto-Abs might have a pathogenic role as indicated by elevated markers of liver damage. Future studies will unravel any novel associations between these two diseases, whether genetic or other.

Detection of Autoantibodies to Vascular Endothelial Growth Factor Receptor-3 in Bile Duct Ligated Rats and Correlations with a Panel of Traditional Markers of Liver Diseases

There is a need for new noninvasive biomarkers (NIBMs) able to assess cholestasis and fibrosis in chronic cholestatic liver diseases (CCLDs). Tumorigenesis can arise from CCLDs. Therefore, autoantibodies to tumor-associated antigens (TAA) may be early produced in response to abnormal self-antigen expression caused by cholestatic injury. Vascular endothelial growth factor receptor-3 (VEGFR-3) has TAA potential since it is involved in cholangiocytes and lymphatic vessels proliferations during CCLDs. This study aims to detect autoantibodies directed at VEGFR-3 during bile duct ligation- (BDL-) induced cholestatic injury in rat sera and investigate whether they could be associated with traditional markers of liver damage, cholestasis, and fibrosis. An ELISA was performed to detect anti-VEGFR-3 autoantibodies in sera of rats with different degree of liver injury and results were correlated with aminotransferases, total bilirubin, and the relative fibrotic area. Mean absorbances of anti-VEGFR-3 autoantibodies were significantly increased from week one to week five after BDL. The highest correlation was observed with total bilirubin (R (2) = 0.8450, P = 3.04e - 12). In conclusion, anti-VEGFR-3 autoantibodies are early produced during BDL-induced cholestatic injury, and they are closely related to cholestasis, suggesting the potential of anti-VEGFR-3 autoantibodies as NIBMs of cholestasis in CCLDs and justifying the need for further investigations in patients with CCLD.