The clinical usage and definition of autoantibodies in immune-mediated liver disease: A comprehensive overview

Autoimmune Hepatitis and Vitamin D Deficiency: A Nationwide Perspective

BACKGROUND

Vitamin D deficiency is linked to worse outcomes in patients with chronic liver diseases (CLD). However, data in patients with autoimmune hepatitis (AIH) remain limited.

AIMS

We aimed to assess the impact of vitamin D deficiency on the outcomes of individuals with AIH.

METHODS

This retrospective cohort study used the TriNetX research network to identify patients with AIH. Patients were matched using propensity score matching and stratified to sufficient vitamin D levels (e.g., 25 (OH) D3 ≥ 30 ng/mL), vitamin D insufficiency (25 (OH) D3: 20-29.9 ng/mL) and vitamin D deficiency (e.g., 25 (OH) D3 < 20 ng/mL). The primary outcome was the all-cause mortality among adult patients with AIH. Secondary outcomes included decompensated liver cirrhosis, acute hepatic failure, liver transplantation (LT), all-cause hospitalizations and all-cause critical care admissions.

RESULTS

A total of 1288 AIH patients with vitamin D deficiency were identified and propensity matched with 1288 patients with normal vitamin D levels. Patients with vitamin D deficiency had significantly increased odds for all-cause mortality compared to those with normal levels (adjusted odds ratio (aOR) = 3.2, 95%CI: 2.3-4.48). Patients with vitamin D deficiency were at increased odds of all-cause hospitalizations (aOR = 2.37, 95%CI: 1.97-2.84), critical care unit admissions (aOR = 2.8, 95%CI: 2.21-3.71), decompensated liver cirrhosis (aOR = 2.74, 95%CI: 2.13-3.54), acute hepatic failure (aOR = 3.11, 95%CI: 2.09-4.62) and LT (aOR = 3.47, 95%CI: 1.71-7.04), as compared to those with normal vitamin D levels.

CONCLUSION

This cohort study showed significantly increased odds for all-cause mortality in AIH patients with vitamin D deficiency. Vitamin D deficiency in patients with AIH was associated with increased likelihood of hospitalisation, decompensated liver cirrhosis, acute liver failure and LT.

Clinical and laboratory characteristics of Sjögren's syndrome-associated autoimmune liver disease: a real-world, 10-year retrospective study

OBJECTIVES

To investigate the clinical and laboratory features of Sjögren's syndrome-associated autoimmune liver disease (SS-ALD) patients and identify potential risk and prognostic factors.

METHODS

SS patients with or without ALD, who visited Tongji Hospital between the years 2011 and 2021 and met the 2012 American College of Rheumatology (ACR) classification criteria for Sjögren's syndrome, were retrospectively enrolled. The clinical and laboratory data of the enrolled patients, including autoimmune antibodies, were collected and analyzed with principal component analysis, correlation analysis, LASSO regression, and Cox regression.

RESULTS

A total of 117 SS-ALD patients were confirmed out of 568 SS patients. Compared to SS-non-ALD patients (n = 451), SS-ALD patients exhibited more severe involvement of the hepatic and hematologic systems, albeit with less pronounced typical SS symptoms. Disease activity was higher in SS-ALD patients, as indicated by elevated ESR, CRP, and IL-6 levels, particularly in the SS-overlap subgroup. Furthermore, SS-AIH patients without AIH-specific autoantibody testing or with negative testing results had higher AST and ALT levels than those who were autoantibody-positive. Our predictive model, incorporating IgG, IgM, AST, GGT, ALT, and C4, effectively identified ALD complications in SS patients, achieving an AUC of 0.924. Additionally, a grimmer prognosis was associated with higher baseline AST and ALT levels.

CONCLUSIONS

SS-ALD patients often manifest with an insidious onset and atypical SS symptoms, yet frequently exhibit severe systemic involvement, intense inflammatory and immune responses, and a poor prognosis. To improve the clinical outcomes in SS-ALD patients, regular monitoring, early identification, and active treatment should be applied. Key Points • The study provided a detailed profile of clinical and laboratory features of SS-ALD and SS-non-ALD patients, contributing to a predictive model of ALD complications in SS patients • SS-ALD patients manifested with an insidious onset but exhibited severe systemic involvement, robust inflammatory and immune responses, and poor prognosis • SS-AIH patients without available testing for AIH-specific autoantibodies or with negative results demonstrated worse liver function, thus routine screening for autoimmune liver antibodies is recommended in SS patients • More severe baseline liver function status was associated with poorer therapeutic responses to routine medications, so early detection and timely intervention are essential for SS patients.

Liver fibrosis is closely linked with metabolic-associated diseases in patients with autoimmune hepatitis

BACKGROUND

This cross-sectional study aimed to investigate the impact of metabolic-associated diseases (MADs) on patients with autoimmune hepatitis (AIH).

METHODS

The study analyzed the clinical characteristics of 283 AIH patients who underwent liver biopsy between January 2016 and February 2022 in Ruijin Hospital, Shanghai, China.

RESULTS

Among the identified AIH patients (n = 283), 87.3%, 23.0%, or 43.1% had MADs, non-alcoholic fatty liver disease (NAFLD), or severe fibrosis, respectively. The proportion of diabetes mellitus (DM) was significantly higher in patients with severe liver fibrosis than in those with mild or moderate fibrosis in the AIH cohort (31.1% vs. 18.0%, p < 0.05). Fibrosis was also more severe in patients with NAFLD than in those without (53.8% vs. 39.9%, p < 0.05). Age, Plts, IgG and the presence with MADs were identified as independent predictors of the severity of inflammation in AIH patients. Moreover, severe liver fibrosis (stages 3 to 4) was independently associated with male (OR, 2.855; p = 0.025), γ-GT (OR, 0.997; p = 0.007), and combination with MADs (OR, 4.917; p = 0.006). Furthermore, combination with DM was also an independent predictor of severe liver fibrosis in AIH patients (OR, 2.445, p = 0.038).

CONCLUSIONS

Concurrent MADs, common in AIH patients, is an independent risk factor for severe fibrosis or inflammation; of note, combination with DM was also an independent predictor of severe liver fibrosis in AIH patients. While managing with AIH, routine assessment of co-existing MADs, especially DM, is also important.

Autoimmune liver disease and multiple sclerosis: state of the art and future perspectives

Clinical observations suggest that the prevalence of autoimmune diseases is changing over time. Both autoimmune liver diseases and multiple sclerosis have shown a significant increase in the last decades. Although the coexistence of autoimmune diseases within individuals and families is a common phenomenon, the extent to which liver disease and multiple sclerosis co-occur is not clear. Case reports and few studies have reported the possible coexistence of multiple sclerosis with thyroid diseases, inflammatory bowel disease, psoriasis, and rheumatoid arthritis. It is unknown whether there is a definite association between multiple sclerosis and autoimmune liver diseases. We reviewed the literature to summarize the available studies on the association between different autoimmune liver diseases (autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis) and treated or untreated multiple sclerosis.

Nomenclature, diagnosis and management of drug-induced autoimmune-like hepatitis (DI-ALH): An expert opinion meeting report

Drug-induced liver injury (DILI) can mimic almost all other liver disorders. A phenotype increasingly ascribed to drugs is autoimmune-like hepatitis (ALH). This article summarises the major topics discussed at a joint International Conference held between the Drug-Induced Liver Injury consortium and the International Autoimmune Hepatitis Group. DI-ALH is a liver injury with laboratory and/or histological features that may be indistinguishable from those of autoimmune hepatitis (AIH). Previous studies have revealed that patients with DI-ALH and those with idiopathic AIH have very similar clinical, biochemical, immunological and histological features. Differentiating DI-ALH from AIH is important as patients with DI-ALH rarely require long-term immunosuppression and the condition often resolves spontaneously after withdrawal of the implicated drug, whereas patients with AIH mostly require long-term immunosuppression. Therefore, revision of the diagnosis on long-term follow-up may be necessary in some cases. More than 40 different drugs including nitrofurantoin, methyldopa, hydralazine, minocycline, infliximab, herbal and dietary supplements (such as Khat and Tinospora cordifolia) have been implicated in DI-ALH. Understanding of DI-ALH is limited by the lack of specific markers of the disease that could allow for a precise diagnosis, while there is similarly no single feature which is diagnostic of AIH. We propose a management algorithm for patients with liver injury and an autoimmune phenotype. There is an urgent need to prospectively evaluate patients with DI-ALH systematically to enable definitive characterisation of this condition.

Viral hepatitis is associated with increased risk of decompensated cirrhosis or liver failure in patients positive for liver cytosol antibody type 1

Liver cytosol antibody type 1 (anti-LC1) is reported to be a marker of type 2 autoimmune hepatitis (AIH), a type of autoimmune liver disease (AILD). However, anti-LC1 is not entirely disease-specific, and its clinical value in other hepatic diseases has not been well elucidated. Our study aimed to explore the associations between the diagnoses and outcome of decompensated cirrhosis or liver failure (DC/LF) in patients positive for anti-LC1. A total of 157 patients positive for anti-LC1 were included in our final analysis. DC/LF was defined as the outcome of patients positive for anti-LC1. The risk of DC/LF according to diagnosis was estimated using multivariable Cox proportional hazards models, while stratified Cox regression models were used in the subgroup analyses. The diagnoses of patients positive for anti-LC1 were found to be comprised of various liver disorders. Versus other diagnoses, viral hepatitis was associated with a 2.25-fold increased risk of DC/LF in these patients, independent of sex, age, disease course, treatment and drinking history. Additionally, the associations were more significant by subgroup analysis in male patients, younger patients, non-newly diagnosed patients, patients without treatment and patients without drinking history. Anti-LC1 is not a disease-specific antibody, as it was found in multiple types of hepatic disease. Furthermore, viral hepatitis rather than AILD was associated with an increased risk of DC/LF in patients positive for anti-LC1. These findings emphasize the important role of viral hepatitis in the progression of DC/LF in patients positive for anti-LC1.

Laboratory risk factors for coexistent primary biliary cholangitis in patients with Sjögren's syndrome: a retrospective study

BACKGROUND

Limited research exists on the laboratory characteristics of coexistent primary biliary cholangitis (PBC) and Sjögren's syndrome (SS). This study aimed to investigate the laboratory risk factors for the coexistence of PBC in patients with SS.

METHODS

Eighty-two patients with coexistent SS and PBC (median age 52.50 years) and 82 age- and sex-matched SS controls were retrospectively enrolled between July 2015 and July 2021. The clinical and laboratory characteristics of the two groups were compared. Laboratory risk factors for the coexistence of PBC in patients with SS were analyzed using logistic regression analysis.

RESULTS

Both groups had a similar prevalence of hypertension, diabetes, thyroid disease, and interstitial lung disease. Compared with the SS group, patients in the SS + PBC group had higher levels of liver enzymes, immunoglobulins M (IgM), G2, and G3 (P < 0.05). The percentage of patients with an antinuclear antibody (ANA) titre > 1:10000 in the SS + PBC group was 56.1%, higher than that in the SS group (19.5%, P < 0.05). Additionally, cytoplasmic, centromeric, and nuclear membranous patterns of ANA and positive anti-centromere antibody (ACA) were observed more frequently in the SS + PBC group (P < 0.05). Logistic regression analysis showed that elevated IgM levels, high ANA titre, cytoplasmic pattern, and ACA were independent risk factors for PBC coexistence in SS.

CONCLUSIONS

In addition to established risk factors, elevated IgM levels, positive ACA, and high ANA titre with cytoplasmic pattern provide clues to clinicians for the early screening and diagnosis of PBC in patients with SS.

NUDT1 promotes the accumulation and longevity of CD103+ TRM cells in primary biliary cholangitis

BACKGROUND & AIMS

Pyruvate dehydrogenase (PDC)-E2 specific CD8⁺ T cells play a leading role in biliary destruction in PBC. However, there are limited data on the characterization of these autoantigen-specific CD8⁺ T cells, particularly in the liver. Herein, we aimed to identify pathogenic intrahepatic CD8⁺ T-cell subpopulations and investigate their immunobiology in PBC.

METHODS

Phenotypic and functional analysis of intrahepatic T-cell subsets were performed by flow cytometry. CD103⁺ T_RM cell frequency was evaluated by histological staining. The transcriptome and metabolome were analyzed by RNA-seq and liquid chromatography-mass spectrometry, respectively. Cytotoxicity of T_RM cells against cholangiocytes was assayed in a 3D organoid co-culture system. Moreover, the longevity (long-term survival) of T_RM cells in vivo was studied by 2-octynoic acid-BSA (2OA-BSA) immunization, Nudt1 conditional knock-out and adoptive co-transfer in a murine model.

RESULTS

Intrahepatic CD103⁺ T_RM (CD69⁺CD103⁺CD8⁺) cells were significantly expanded, hyperactivated, and potentially specifically reactive to PDC-E2 in patients with PBC. CD103⁺ T_RM cell frequencies correlated with clinical and histological indices of PBC and predicted poor ursodeoxycholic acid response. NUDT1 blockade suppressed the cytotoxic effector functions of CD103⁺ T_RM cells upon PDC-E2 re-stimulation. NUDT1 overexpression in CD8⁺ T cells promoted tissue-residence programming in vitro; inhibition or knockdown of NUDT1 had the opposite effect. Pharmacological blockade or genetic deletion of NUDT1 eliminated CD103⁺ T_RM cells and alleviated cholangitis in mice immunized with 2OA-BSA. Significantly, NUDT1-dependent DNA damage resistance potentiates CD8⁺ T-cell tissue-residency via the PARP1-TGFβR axis in vitro. Consistently, PARP1 inhibition restored NUDT1-deficient CD103⁺ T_RM cell durable survival and TGFβ-Smad signaling.

CONCLUSIONS

CD103⁺ T_RM cells are the dominant population of PDC-E2-specific CD8⁺ T lymphocytes in the livers of patients with PBC. The role of NUDT1 in promoting pathogenic CD103⁺ T_RM cell accumulation and longevity represents a novel therapeutic target in PBC.

LAY SUMMARY

Primary biliary cholangitis (PBC) is a rare inflammatory condition of the bile ducts. It can be treated with ursodeoxycholic acid, but a large percentage of patients respond poorly to this treatment. Liver-infiltrating memory CD8⁺ T cells recognizing the PDC-E2 immunodominant epitope are critical in the pathogenesis of PBC. We identifed the key pathogenic CD8⁺ T cell subset, and worked out the mechanisms of its hyperactivation and longevity, which could be exploited therapeutically.

EASL Clinical Practice Guidelines on sclerosing cholangitis

Management of primary or secondary sclerosing cholangitis is challenging. These Clinical Practice Guidelines have been developed to provide practical guidance on debated topics including diagnostic methods, prognostic assessment, early detection of complications, optimal care pathways and therapeutic (pharmacological, endoscopic or surgical) options both in adults and children.

Diagnostic and Clinical Value of Specific Autoantibodies against Kelch-like 12 Peptide and Nuclear Envelope Proteins in Patients with Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease characterized by the presence of antimitochondrial and antinuclear antibodies in patients’ serum. Here, we analyzed the reactivity of autoantibodies against a novel autoantigen, kelch-like 12 (KLHL12) protein, in a cohort of 138 PBC and 90 non-PBC patients. Additionally, we compared the reactivity of KLHL12 with antinuclear envelope antibodies: anti-gp210, anti-p62, and anti-LBR. Commercially available kits and an ‘in-house’ ELISA were used in the studies. Antinuclear envelope antibodies were detected in 65% of PBC patients and the presence of these antibodies was observed more frequently in patients diagnosed with later stages (III/IV) of PBC, according to Ludwig’s classification (p < 0.05) and were found to correlate with a higher concentration of bilirubin. Overall, anti-KLHL12 antibodies were found more frequently in PBC patients than in non-PBC controls (p < 0.001). Anti-KLHL12 antibodies were detected in 36% of the tested PBC cohort, including PBC patients negative for antimitochondrial antibodies. Presence of anti-KLHL12 was also associated with a higher concentration of bilirubin and correlated with fibrosis (p < 0.05). Anti-KLHL12 antibodies were detected in 30% of PBC individuals positive for antinuclear envelope antibodies, while anti-KLHL12 and antinuclear envelope antibodies were found in 17% of all PBC cases. Concluding, our data confirm that antibodies against the KLHL12 protein are highly specific for PBC and when used in combination with other markers, may significantly increase the diagnosis of PBC.

Autoimmmune hepatitis

Autoimmune hepatitis (AIH) is a T-cell mediated, inflammatory liver disease affecting all ages and characterized by female preponderance, elevated serum transaminase and immunoglobulin G levels, positive circulating autoantibodies, and presence of interface hepatitis at liver histology. AIH type 1, affecting both adults and children, is defined by positive anti-nuclear and/or anti-smooth muscle antibodies, while type 2 AIH, affecting mostly children, is defined by positive anti-liver-kidney microsomal type 1 and/or anti-liver cytosol type 1 antibody. While the autoantigens of type 2 AIH are well defined, being the cytochrome P4502D6 (CYP2D6) and the formiminotransferase cyclodeaminase (FTCD), in type 1 AIH they remain to be identified. AIH-1 predisposition is conferred by possession of the MHC class II HLA DRB1*03 at all ages, while DRB1*04 predisposes to late onset disease; AIH-2 is associated with possession of DRB1*07 and DRB1*03. The majority of patients responds well to standard immunosuppressive treatment, based on steroid and azathioprine; second- and third-line drugs should be considered in case of intolerance or insufficient response. This review offers a comprehensive overview of pathophysiological and clinical aspects of AIH.

Selected transgenic murine models of human autoimmune liver diseases

Murine models of human diseases are of outmost importance for both studying molecular mechanisms driving their development and testing new treatment strategies. In this review, we first discuss the etiology and risk factors for autoimmune liver disease, including primary biliary cholangitis, autoimmune hepatitis and primary sclerosing cholangitis. Second, we highlight important features of murine transgenic models that make them useful for basic scientists, drug developers and clinical researchers. Next, a brief description of each disease is followed by the characterization of selected animal models.

Autoimmune Hepatitis: Serum Autoantibodies in Clinical Practice

Circulating autoantibodies are a key diagnostic tool in autoimmune hepatitis (AIH), being positive in 95% of the cases if tested according to dedicated guidelines issued by the International Autoimmune Hepatitis Group. They also allow the distinction between type 1 AIH, characterized by positive anti-nuclear and/or anti-smooth muscle antibody, and type 2 AIH, characterized by positive anti-liver kidney microsomal type 1 and/or anti-liver cytosol type 1 antibody. Anti-soluble liver antigen is the only AIH-specific autoantibody, and is found in 20-30% of both type 1 and type 2 AIH. Anti-neutrophil cytoplasmic antibody is frequently positive in type 1 AIH, being associated also with inflammatory bowel disease and with primary/autoimmune sclerosing cholangitis. The reference method for autoantibody testing remains indirect immunofluorescence on triple tissue (rodent liver, kidney and stomach), allowing both the detection of the majority of liver-relevant reactivities, including those autoantibodies whose molecular target antigens are unknown. Of note, the current knowledge of the clinical significance of autoantibodies relies on studies based on this technique. However, immunofluorescence requires trained laboratory personnel, is observer-dependent, and lacks standardization, leading to ongoing attempts at replacing this method with automated assays, the sensitivity, and specificity of which, however, require further studies before they can be used as a reliable alternative to immunofluorescence; currently, they may be used as complementary to immunofluorescence.

Detection of anti-kelch-like 12 and anti-hexokinase 1 antibodies in primary biliary cholangitis patients in China

OBJECTIVES

primary biliary cholangitis (PBC) is a chronic cholestatic disease, characterized by positive anti-mitochondrial autoantibodies (AMA) in 90-95 % patients. Anti-kelch-like 12 (anti-KLHL12) and anti-hexokinase1 (anti-HK1) antibodies have been identified as the two new serum markers in recent years, which are used in the diagnosis of AMA-negative PBC patients. The objective of the study was to examine the performance of these two new biomarkers in China.

METHODS

a total of 192 patients were enrolled and screened for anti-KLHL12 and anti-HK1 antibodies and AMA by ELISA. Receiver operating characteristic (ROC curve) analysis was applied to examine the diagnostic importance of AMA, anti-KLHL12 and anti-HK1 antibodies. Furthermore, correlation analysis between some important biochemical indexes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase [ALP], bilirubin, gamma-glutamil transferasa [γ-GT]), staging of pathological changes of the liver and the expression of novel antibodies in PBC patients were also examined.

RESULTS

the positivity of the anti-HK1 antibody in AMA-positive PBC patients and AMA-negative patients was 44.7 % and 33.3 %, respectively. The specificity, proportion of positive patients (PPV) and proportion of negative patients (NPV) were 93 %, 89 % and 53 %, respectively. In contrast, the positivity to the anti-KLHL12 antibody in AMA-positive and negative PBC patients was 41.2 % and 22.2 %, respectively. Specificity, PPV and NPV were 98 %, 95 % and 52 %, respectively. The area under the curve (AUC) with anti-HK1 and anti-KLHL12 antibodies were 0.720 and 0.703. With the combination with anti-HK1 and anti-KLHL12 antibodies, the AUC of AMA increased from 0.889 to 0.891, increasing the sensitivity from 0.764 to 0.836. Anti-KLHL12 and anti-HK1-positive patients had higher serum levels of ALP, γ-GT and bilirubin, with statistically significant differences (p < 0.01) compared with anti-KLHL12 or anti-HK1-negative patients. Notably, correlation analysis showed a significant positive correlation between antibody expression and ALP, γ-GT and bilirubin serum levels (r = 0.735, 0.491, 0.466; p < 0.01).

CONCLUSIONS

anti-HK1 and anti-KLHL12 antibodies have been identified as two significant biomarkers in PBC patients. Furthermore, the presence of these antibodies is likely to correlate with the severity of PBC.

Acute autoimmune-like hepatitis with atypical anti-mitochondrial antibody after mRNA COVID-19 vaccination: A novel clinical entity?

Autoimmune phenomena and clinically apparent autoimmune diseases, including autoimmune hepatitis, are increasingly been reported not only after natural infection with the SARS-CoV-2 virus, but also after vaccination against it. We report the case of a 63-year old man without a history of autoimmunity or SARS-CoV-2 natural infection who experienced acute severe autoimmune-like hepatitis seven days after the first dose of the mRNA-1273 SARS-CoV-2 vaccine. Liver histology showed inflammatory portal infiltrate with interface hepatitis, lobular and centrilobular inflammation with centrilobular necrosis, in absence of fibrosis and steatosis. Serum immunoglobulin G was slightly elevated. Autoimmune liver serology showed an indirect immunofluorescence pattern on triple rodent tissue compatible with anti-mitochondrial antibody (AMA), but, unexpectedly, this pattern was not mirrored by positivity for primary biliary cholangitis (PBC)-specific molecular tests, indicating that this antibody is different from classical AMA. Anti-nuclear antibody (ANA) was also positive with a rim-like indirect immunofluorescence pattern on liver and HEp2 cell substrates, similar to PBC-specific ANA; however, anti-gp210 and a large panel of molecular-based assays for nuclear antigens were negative, suggesting a unique ANA in our patient. He carries the HLA DRB1*11:01 allele, which is protective against PBC. Response to prednisone treatment was satisfactory. The clinical significance of these novel specificities needs to be further evaluated in this emerging condition.

Decompensated Cirrhosis as Presentation of LKM1/LC1 Positive Type 2 Autoimmune Hepatitis in Adulthood. A Rare Clinical Entity of Difficult Management

Background: Autoimmune hepatitis (AIH) is a chronic and aggressive liver disease that rapidly evolves into cirrhosis and end-stage liver disease if not timely diagnosed and treated with immunosuppressive therapy. AIH is classified into type 1 and type 2 according to the autoantibody pattern, with smooth muscle antibodies and/or antinuclear antibodies as serological markers of AIH-1, while antiliver cytosol antibody type 1 and/or antiliver/kidney microsomal antibody type 1 characterize type 2 AIH, which mainly affects children, including infants, and adolescents. Case Summary: We describe a case of type 2 AIH, clinically onset in a 34-year-old woman with decompensated cirrhosis. Only a thorough analysis of the autoantibody profile allowed for a diagnosis of an AIH-2 evolved into cirrhosis. The patient received a moderate corticosteroid therapy without achieving optimal disease control. We discuss the controversial decision of whether or not to treat the patient with immunosuppressive therapy, which should be balanced with the potential risk of infectious and other complications. A review of the literature on the management of patients with autoimmune cirrhosis is also presented. Conclusions: AIH-2 can be clinically onset in adult patients with cirrhosis and its complications, without being preceded by major clinical signs. Due to the difficult management of cirrhosis with immunosuppressive treatments, a patient-tailored strategy with a case-by-case approach is needed to prevent major complications such as infections, potentially precluding liver transplantation the only curative therapy.

Clinical characteristics and HLA genotypes in Chinese patients with anti-SLA/LP-positive autoimmune hepatitis

Background

Anti-soluble liver antigen/liver pancreas (anti-SLA/LP) is a highly specific serological marker for the diagnosis of autoimmune hepatitis (AIH). The aim of the present study was to define the clinical characteristics and human leucocyte antigen (HLA) genotypes of Chinese patients with anti-SLA/LP positive AIH.

Methods

Ninety-one AIH patients who were anti-SLA/LP positive were enrolled in this case control study. Clinical information was obtained through reviewing patients’ clinical notes. High-resolution genotyping of HLA-A, B, C, DRB1, and DQB1 alleles was performed by sequence-based typing polymerase chain reaction on 62 of the 91 patients. Data from 500 healthy patients were used as baseline controls.

Results

Anti-SLA/LP-positive AIH patients were characterized as follows: adults (age 20–80 years), female (88%), and frequent anti-nuclear antibody positivity (91%). Genetically, compared with the controls, HLA-B*35:01 and C*08:01 were significantly more frequent in patients. The frequencies of HLA-B*08:01, B*40:02, DRB1*04:01, DRB1*04:05, DRB1*14:01, and DRB1*16:02 increased, and the frequency in DRB1*15:01 decreased in patients, but did not reach significance after Bonferroni’s correction. Patients with other autoimmune diseases had a higher DRB1*04:05 and DQB1*04:01 allele carrier frequency than those without. DRB1*04:05 and DQB1*04:01 alleles were found at increased frequency in patients with decompensated liver disease than those with compensated liver disease.

Conclusions

Chinese anti-SLA/LP-positive AIH patients have some distinct clinical characteristics than other populations reported in the literature. The presence of certain specific HLA alleles could potentially increase the risk of developing anti-SLA/LP-positive AIH or other autoimmune disease and decompensated liver disease in the Chinese population.

Classification of invasive bloodstream infections and Plasmodium falciparum malaria using autoantibodies as biomarkers

A better understanding of disease-specific biomarker profiles during acute infections could guide the development of innovative diagnostic methods to differentiate between malaria and alternative causes of fever. We investigated autoantibody (AAb) profiles in febrile children (≤ 5 years) admitted to a hospital in rural Ghana. Serum samples from 30 children with a bacterial bloodstream infection and 35 children with Plasmodium falciparum malaria were analyzed using protein microarrays (Protoplex Immune Response Assay, ThermoFisher). A variable selection algorithm was applied to identify the smallest set of AAbs showing the best performance to classify malaria and bacteremia patients. The selection procedure identified 8 AAbs of which IFNGR2 and FBXW5 were selected in repeated model run. The classification error was 22%, which was mainly due to non-Typhi Salmonella (NTS) diagnoses being misclassified as malaria. Likewise, a cluster analysis grouped patients with NTS and malaria together, but separated malaria from non-NTS infections. Both current and recent malaria are a risk factor for NTS, therefore, a better understanding about the function of AAb in disease-specific immune responses is required in order to support their application for diagnostic purposes.

Primary biliary cholangitis with normal alkaline phosphatase: A neglected clinical entity challenging current guidelines

BACKGROUND & AIM

The diagnosis of primary biliary cholangitis (PBC), an uncommon immune-mediated cholestatic liver disease, is based on positive circulating anti-mitochondrial (AMA) and/or PBC-specific anti-nuclear autoantibodies (ANA), coupled with elevated serum alkaline phopsphatase (ALP) levels. Timely initiation of treatment with ursodeoxycholic acid prevents progression to cirrhosis and liver failure. We aimed at investigating liver histology in patients with normal ALP level and positive AMA and/or PBC-specific ANA.

METHODS

We searched the Swiss PBC Cohort Study database, which includes subjects with positive PBC autoimmune serology and normal ALP levels, for patients who underwent a liver biopsy. Histological slides were centrally reviewed by an expert liver pathologist, and sera were centrally re-tested for AMA and ANA.

RESULTS

30 patients were included; 90% females, median age 53 (range 27-72) years. Twenty-four (80%) had liver histology typical for (n = 2), consistent with (n = 16) or suggestive of (n = 6) PBC, including three of four AMA-negative ANA-positive patients. Among 22 ursodeoxycholic acid treated patients, 14 had elevated GGT levels before treatment; a significant decrease of the median GGT level between pre- (1.46 x ULN) and post- (0.43 x ULN) treatment (p = 0.0018) was observed.

CONCLUSIONS

In our series, a high proportion of AMA positive patients with normal ALP levels have PBC. For the first time we show histological diagnosis of PBC in AMA-negative/PBC-specific ANA-positive subjects and the potential role of GGT as a biomarker in PBC patients with normal baseline ALP levels. Current guidelines for the diagnosis of PBC do not cover the whole extent of PBC presentation, with important clinical implications in terms of timely treatment initiation.

Primary biliary cholangitis management: controversies, perspectives and daily practice implications from an expert panel

Primary biliary cholangitis (PBC) is a rare progressive immune-mediated liver disease that, if not adequately treated, may culminate in end-stage disease and need for transplantation. According to current guidelines, PBC is diagnosed in the presence of antimitochondrial antibodies (AMA) or specific antinuclear antibodies, and of a cholestatic biochemical profile, while biopsy is recommended only in selected cases. All patients receive ursodeoxycholic acid (UDCA) in first line; the only registered second-line therapy is obeticholic acid (OCA) for UDCA-inadequate responders. Despite the recent advances in understanding PBC pathogenesis and developing new treatments, many grey areas remain. Six Italian experts selected the following topics as the most urgent to address in PBC management: diagnosis and natural history of PBC: as a portion of the subjects with isolated AMA, normal alkaline phosphatase (ALP) levels and no symptoms of liver disease could have PBC by histology, defining how to manage and follow this population is crucial; role of liver biopsy: recent evidence suggests that biopsy may provide relevant information for risk stratification and prediction of UDCA response, possibly facilitating personalized approaches; risk stratification: the tools for risk stratification are well established, but some issues (eg bile acid dosage in routine practice) remain controversial; and therapy: those in more advanced stages of development are nuclear receptor modulators and fibrates, but more data are needed to plan personalized strategies. In this manuscript, for each topic, current evidence, controversies and future perspectives are summarized with the possible implications for clinical practice.

Animal Models of Autoimmune Liver Diseases: a Comprehensive Review

Autoimmune liver diseases (AILDs) are potentially life-threatening chronic liver diseases which include autoimmune hepatitis, primary biliary cholangitis, primary sclerosing cholangitis, and recently characterized IgG4-related sclerosing cholangitis. They are caused by immune attack on hepatocytes or bile ducts, with different mechanisms and clinical manifestations. The etiologies of AILDs include a susceptible genetic background, environment insults, infections, and changes of commensal microbiota, but remain complicated. Understanding of the underlying mechanisms of AILDs is mandatory for early diagnosis and intervention, which is of great importance for better prognosis. Thus, animal models are developed to mimic the pathogenesis, find biomarkers for early diagnosis, and for therapeutic attempts of AILDs. However, no animal models can fully recapitulate features of certain AILD, especially the late stages of diseases. Certain limitations include different living condition, cell composition, and time frame of disease development and resolution. Moreover, there is no IgG4 in rodents which exists in human. Nevertheless, the understanding and therapy of AILDs have been greatly advanced by the development and mechanistic investigation of animal models. This review will provide a comprehensive overview of traditional and new animal models that recapitulate different features and etiologies of distinct AILDs.

Cholangiocarcinoma in Patients with Primary Sclerosing Cholangitis (PSC): a Comprehensive Review

Cholangiocarcinoma (CCA) is the most common malignancy in patients with primary sclerosing cholangitis (PSC) and carries a high rate of mortality. Although the pathogenesis of CCA in PSC is largely unknown, inflammation-driven carcinogenesis concomitant with various genetic and epigenetic abnormalities are underlying factors. The majority of CCA cases develop from a dominant stricture (DS), which is defined as a stricture with a diameter < 1.5 mm in the common bile duct or < 1.0 mm in the hepatic duct. In PSC patients presenting with an abrupt aggravation of jaundice, pain, fatigue, pruritus, weight loss, or worsening liver biochemistries, CCA should be suspected and evaluated utilizing a variety of diagnostic modalities. However, early recognition of CCA in PSC remains a major challenge. Importantly, 30-50% of CCA in PSC patients are observed within the first year following the diagnosis of PSC followed by an annual incidence ranging from 0.5 to 1.5 per 100 persons, which is nearly 10 to 1000 times higher than that in the general population. Cumulative 5-year, 10-year, and lifetime incidences are 7%, 8-11%, and 9-20%, respectively. When PSC-associated CCA is diagnosed, most tumors are unresectable, and no effective medications are available. Given the poor therapeutic outcome, the surveillance and management of PSC patients who are at an increased risk of developing CCA are of importance. Such patients include older males with large-duct PSC and possibly concurrent ulcerative colitis. Thus, more attention should be paid to patients with these clinical features, in particular within the first year after PSC diagnosis. In contrast, CCA is less frequently observed in pediatric or female PSC patients or in those with small-duct PSC or concurrent Crohn's disease. Recently, new biomarkers such as antibodies to glycoprotein 2 have been found to be associated with an increased risk of developing CCA in PSC. Herein, we review the literature on the pathogenesis, incidence, clinical features, and risk factors, with a focus on various diagnostic modalities of PSC-associated CCA.

The search for the Holy Grail: autoantigenic targets in primary sclerosing cholangitis associated with disease phenotype and neoplasia

Unlike in other autoimmune liver diseases such as autoimmune hepatitis and primary biliary cholangitis, the role and nature of autoantigenic targets in primary sclerosing cholangitis (PSC), a progressive, chronic, immune-mediated, life threatening, genetically predisposed, cholestatic liver illness, is poorly elucidated. Although anti-neutrophil cytoplasmic antibodies (ANCA) have been associated with the occurrence of PSC, their corresponding targets have not yet been identified entirely. Genome-wide association studies revealed a significant number of immune-related and even disease-modifying susceptibility loci for PSC. However, these loci did not allow discerning a clear autoimmune pattern nor do the therapy options and the male gender preponderance in PSC support a pathogenic role of autoimmune responses. Nevertheless, PSC is characterized by the co-occurrence of inflammatory bowel diseases (IBD) demonstrating autoimmune responses. The identification of novel autoantigenic targets in IBD such as the major zymogen granule membrane glycoprotein 2 (GP2) or the appearance of proteinase 3 (PR3) autoantibodies (autoAbs) have refocused the interest on a putative association of loss of tolerance with the IBD phenotype and consequently with the PSC phenotype. Not surprisingly, the report of an association between GP2 IgA autoAbs and disease severity in patients with PSC gave a new impetus to autoAb research for autoimmune liver diseases. It might usher in a new era of serological research in this field. The mucosal loss of tolerance against the microbiota-sensing GP2 modulating innate and adaptive intestinal immunity and its putative role in the pathogenesis of PSC will be elaborated in this review. Furthermore, other potential PSC-related autoantigenic targets such as the neutrophil PR3 will be discussed. GP2 IgA may represent a group of new pathogenic antibodies, which share characteristics of both type 2 and 3 of antibody-mediated hypersensitive reactions according to Coombs and Gell.

The use of biologics in the treatment of autoimmune liver disease

Introduction: Autoimmune liver diseases include autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and juvenile autoimmune hepatitis (JAIH). The pathophysiologic features of each disease vary, but generally include presence of autoantibodies, cytokine abnormalities, and/or T and B cell autoreactivity.Areas covered: This article compares conventional therapy with newer biologics available for treatment of autoimmune liver diseases. Conventional therapy involves the use of immunosuppressive agents, or other treatment modalities for specific autoimmune liver diseases such as ursodeoxycholic acid and fibrates for PBC. Biologics were developed to target the production of autoantibodies by B cells, the presence of proinflammatory cytokines, adhesion molecules or T and B cell activation.Expert opinion: Despite the promise of biologics being able to target specific cellular and humoral pathways, results have been generally poor, and safety has not been as expected. Cases of autoimmune hepatitis have also developed with the use of these biologicals. Reasons for the lack of success of biologics in treating autoimmune liver disease has led to a reevaluation of our understanding of underlying pathogenesis, demonstrating that while our knowledge of the immunity has improved over the past two decades, it is far from complete.

The challenges of primary biliary cholangitis: What is new and what needs to be done

Primary Biliary Cholangitis (PBC) is an uncommon, chronic, cholangiopathy of autoimmune origin and unknown etiology characterized by positive anti-mitochondrial autoantibodies (AMA), female preponderance and progression to cirrhosis if left untreated. The diagnosis is based on AMA- or PBC-specific anti-nuclear antibody (ANA)-positivity in the presence of a cholestatic biochemical profile, histologic confirmation being mandatory only in seronegative cases. First-line treatment is ursodeoxycholic acid (UDCA), which is effective in preventing disease progression in about two thirds of the patients. The only approved second-line treatment is obeticholic acid. This article summarizes the most relevant conclusions of a meeting held in Lugano, Switzerland, from September 23rd-25th 2018, gathering basic and clinical scientists with various background from around the world to discuss the latest advances in PBC research. The meeting was dedicated to Ian Mackay, pioneer in the field of autoimmune liver diseases. The role of liver histology needs to be reconsidered: liver pathology consistent with PBC in AMA-positive individuals without biochemical cholestasis is increasingly reported, raising the question as to whether biochemical cholestasis is a reliable disease marker for both clinical practice and trials. The urgent need for new biomarkers, including more accurate markers of cholestasis, was also widely discussed during the meeting. Moreover, new insights in interactions of bile acids with biliary epithelia in PBC provide solid evidence of a role for impaired epithelial protection against potentially toxic hydrophobic bile acids, raising the fundamental question as to whether this bile acid-induced epithelial damage is the cause or the consequence of the autoimmune attack to the biliary epithelium. Strategies are needed to identify difficult-to-treat patients at an early disease stage, when new therapeutic approaches targeting immunologic pathways, in addition to bile acid-based therapies, may be effective. In conclusion, using interdisciplinary approaches, groundbreaking advances can be expected before long in respect to our understanding of the etiopathogenesis of PBC, with the ultimate aim of improving its treatment.

Precision medicine for autoimmune hepatitis

Autoimmune hepatitis (AIH) is an autoimmune liver disease induced by environmental factors in genetically susceptible individuals. AIH is characterized by hypergammaglobulinemia, elevation of serum autoantibodies and transaminases, and interface hepatitis. Personalized therapy is necessary in AIH because of its heterogeneity in clinical manifestations. Precision medicine is a recent and novel therapeutic pattern which ultimately aims to achieve personalized therapy. In this review we summarize the research progress of precision medicine to treat AIH by an exploration of the susceptible genes, precision diagnosis and prognosis of AIH, pharmacogenomics and precision medication, and the precision treatment for special types of AIH.