Consensus recommendations for histological criteria of autoimmune hepatitis from the International AIH Pathology Group: Results of a workshop on AIH histology hosted by the European Reference Network on Hepatological Diseases and the European Society of Pathology: Results of a workshop on AIH histology hosted by the European Reference Network on Hepatological Diseases and the European Society of Pathology

Diagnostic features of autoimmune hepatitis in SARS‑CoV‑2‑vaccinated vs. unvaccinated individuals

The global coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected millions of lives, leading to significant morbidity and mortality. With >772 million cases and nearly seven million deaths reported worldwide to date, the development of vaccines has been a critical step in mitigating the impact of COVID-19. However, concerns have arisen regarding the potential for SARS-CoV-2 mRNA vaccination to trigger autoimmune diseases, including autoimmune hepatitis (AIH). The present single-center, retrospective study aimed to compare the clinical and pathological features of AIH in patients with or without a history of SARS-CoV-2 mRNA vaccination. A total of 72 patients with AIH were examined. Among them, 10 had received the SARS-CoV-2 mRNA vaccination prior to AIH onset. These patients exhibited more pronounced CD4+ T cell infiltration into the liver tissue compared with those who were unvaccinated. No significant differences in the levels of other liver enzymes, autoimmune antibodies, or CD8+ T cell infiltration were observed between the groups. Moreover, the AIH patients with a history of SARS-CoV-2 mRNA vaccination had more extensive CD4+ T cell infiltration in their liver tissues than the unvaccinated patients. These findings suggested that the immune response to SARS-CoV-2 mRNA vaccination may influence the pathogenesis of AIH, highlighting the need for further research into the relationship between SARS-CoV-2 mRNA vaccination and autoimmune liver diseases. Such studies will also help clarify the distinction between vaccine-induced liver injury and traditional AIH.

Worse Fibro-inflammatory Activity on Diagnostic Liver Biopsy Adversely Impacts Biochemical Remission in Autoimmune Hepatitis

BACKGROUND

Autoimmune hepatitis (AIH) patients can present with advanced fibrosis at diagnosis or may progress to the same if biochemical remission on treatment is not achieved.

METHODS

We conducted a single-center retrospective analysis of 34 pediatrics and 39 adult AIH patients. Three pathologists, blinded to clinical information, reviewed the diagnostic liver biopsy (DLB) slides of AIH patients. We evaluated the impact of clinical, laboratory, and histopathologic parameters on outcomes including biochemical remission (BR).

RESULTS

Incidence of advanced (Ludwig stage 3 or 4) fibrosis on DLB was 45.2%. AIH patients with advanced fibrosis had higher median Ishak score (p<0.001) and higher IgG level (p=0.01) at diagnosis. The incidence of BR at 6-month (31.2% vs. 88.6%, p=0.001) and 1-year (68.8% vs. 88.6%, p=0.04) post-diagnosis was significantly lower in AIH patients with advanced fibrosis. Although not statistically significant, a higher proportion of AIH patients with advanced fibrosis were on high dose of steroids (58% vs. 37.9%, p=0.1) at 1 year post diagnosis. Higher serum IgG level at diagnosis was associated with lower odds of achieving BR at 6-month (p = 0.004) and 1-year (p=0.03) post-diagnosis in multivariate analysis. Pediatric age at diagnosis (p=0.02) was associated with higher steroid dose at 1-year post-diagnosis in univariate analysis.

CONCLUSIONS

Findings of advanced fibrosis on DLB of AIH patients was accompanied by more pronounced necro-inflammatory activity and higher serum IgG level, which translated to lower rates of BR and higher exposure to steroids during the first year after diagnosis.

Detection of polyreactive immunoglobulin G facilitates diagnosis in children with autoimmune hepatitis

OBJECTIVE

The detection of autoantibodies is essential to diagnose autoimmune hepatitis (AIH). Particularly in children, specificity of autoantibodies decreases due to lower titers being diagnostic and being present not only in AIH but also in other liver diseases. Recently, quantification of polyreactive IgG (pIgG) for detection of adult AIH showed the highest overall accuracy compared to antinuclear antibodies (ANA), anti-smooth muscle antibodies (anti-SMA), anti-liver kidney microsomal antibodies (anti-LKM) and anti-soluble liver antigen/liver pancreas antibodies (anti-SLA/LP). We aimed to evaluate the diagnostic value of pIgG for pediatric AIH.

DESIGN

pIgG, quantified using HIP1R/BSA coated ELISA, and immunofluorescence on rodent tissue sections were performed centrally. The diagnostic fidelity to diagnose AIH was compared to conventional autoantibodies of AIH in training and validation cohorts from a retrospective, European multi-center cohort from nine centers from eight European countries composed of existing biorepositories from expert centers (n = 285).

RESULTS

IgG from pediatric AIH patients exhibited increased polyreactivity to multiple protein and non-protein substrates compared to non-AIH liver diseases and healthy children. pIgG had an AUC of 0.900 to distinguish AIH from non-AIH liver diseases. pIgG had a 31-73% higher specificity than ANA and anti-SMA and comparable sensitivity that was 6-20 times higher than of anti-SLA/LP, anti-LC1 and anti-LKM. pIgG had a 21-34% higher accuracy than conventional autoantibodies, was positive in 43-75% of children with AIH and normal IgG and independent from treatment response.

CONCLUSION

Detecting pIgG improves the diagnostic evaluation of pediatric AIH compared to conventional autoantibodies, primarily owing to higher accuracy and specificity.

NMR-based metabolomic signature: An important tool for the diagnosis and study of pathogenesis of autoimmune hepatitis

BACKGROUND AND AIMS

Metabolomics is used to predict, diagnose, and monitor metabolic disorders but altered metabolomic signatures have also been reported in diverse diseases, including autoimmune disorders. However, the metabolomic profile in autoimmune hepatitis (AIH) has not been investigated in depth. Therefore, we investigated the metabolomic signature of AIH and its significance as a diagnostic and pathogenetic tool.

APPROACH AND RESULTS

Metabolites in plasma samples from 50 patients with AIH at diagnosis, 43 healthy controls, 72 patients with primary biliary cholangitis (PBC), 26 patients with metabolic dysfunction-associated liver disease, and 101 patients with chronic viral hepatitis were determined by 1 H NMR (nuclear magnetic resonance) spectroscopy. Fifty-two metabolites were quantified, and metabolic pathway analysis was performed. Multivariate analysis revealed that AIH could be differentiated from healthy controls and each of the disease controls ( p <0.001). Fifteen metabolites differentiated AIH from disease controls (PBC+chronic viral hepatitis+metabolic dysfunction-associated liver disease) (95% sensitivity and 92% specificity). Ten distinct metabolic pathways were altered in AIH compared to disease controls. The metabolic pathway of branched-chain amino acids (lower valine, leucine, and isoleucine levels and their catabolic intermediates in PBC), methionine (lower methionine, 2-aminobutyrate, and 2-hydroxybutyrate levels in PBC), alanine-aspartate-glutamate (lower metabolites in PBC), and that of metabolites associated with gut microbiota (lower choline, betaine, and dimethylamine levels in PBC) were significantly different between AIH and PBC ( p <0.01).

CONCLUSIONS

1 H NMR spectroscopy could be a promising novel tool to diagnose and study AIH pathogenesis as there is no need for much sample handling, is highly reproducible with high sensitivity and specificity, and low cost.

Diagnostic criteria and long-term outcomes in AIH-PBC variant syndrome under combination therapy

Background & Aims

Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) can co-exist in AIH-PBC, requiring combined treatment with immunosuppression and ursodeoxycholic acid (UDCA). The Paris criteria are commonly used to identify these patients; however, the optimal diagnostic criteria are unknown. We aimed to evaluate the use and clinical relevance of both Paris and Zhang criteria.

Methods

Eighty-three patients with a clinical suspicion of AIH-PBC who were treated with combination therapy were included. Histology was re-evaluated. Characteristics and long-term outcomes were retrospectively compared to patients with AIH and PBC.

Results

Seventeen (24%) patients treated with combination therapy fulfilled the Paris criteria. Fifty-two patients (70%) fulfilled the Zhang criteria. Patients who met Paris and Zhang criteria more often had inflammation and fibrosis on histology compared to patients only meeting the Zhang criteria. Ten-year liver transplant (LT)-free survival was 87.3% (95% CI 78.9-95.7%) in patients with AIH-PBC. This did not differ in patients in or outside the Paris or Zhang criteria (p = 0.46 and p = 0.40, respectively) or from AIH (p = 0.086). LT-free survival was significantly lower in patients with PBC and severe hepatic inflammation - not receiving immunosuppression - compared to those with AIH-PBC (65%; 95% CI 52.2-77.8% vs. 87%; 95% CI 83.2-90.8%; hazard ratio 0.52; p = 0.043).

Conclusions

In this study, patients with AIH-PBC outside Paris or Zhang criteria were frequently labeled as having AIH-PBC and were successfully treated with combination therapy with similar outcomes. LT-free survival was worse in patients with PBC and hepatic inflammation than in those treated as having AIH-PBC. More patients may benefit from combination therapy.

Impact and implications

This study demonstrated that patients with AIH-PBC variant syndrome treated with combined therapy consisting of immunosuppressants and ursodeoxycholic acid often do not fulfill the Paris criteria. They do however have comparable response to therapy and long-term outcomes as patients who do fulfill the diagnostic criteria. Additionally, patients with PBC and additional signs of hepatic inflammation have poorer long-term outcomes compared to patients treated as having AIH-PBC. These results implicate that a larger group of patients with features of both AIH and PBC may benefit from combined treatment. With our results, we call for improved consensus among experts in the field on the diagnosis and management of AIH-PBC variant syndrome.

Clinical Characteristics of Genuine Acute Autoimmune Hepatitis

Introduction

Autoimmune hepatitis (AIH) has a spectrum of symptoms ranging from asymptomatic disease to acute severe hepatitis, chronic hepatitis, and decompensated cirrhosis. The acute presentation is not rare and could represent genuine acute AIH (GAAIH) or acute exacerbation of chronic autoimmune hepatitis. We aimed to identify the prevalence, clinical features, and prognostic factors associated with GAAIH and compare these cases with acute exacerbation of chronic AIH.

Methods

This cross-sectional observational study evaluated patients with acute AIH presentation, defined as total bilirubin >5 times the upper limit of normality (xULN) and/or alanine aminotransferase >10 xULN, and no prior history of liver disease. Histology findings of acute disease defined GAAIH. Bivariate analyses were performed to identify factors associated with the GAAIH, when compared with acute exacerbation of chronic AIH.

Results

Seventy-two patients with acute presentation of AIH were included and six (8.3%) of them presented GAAIH. Comparative analysis between patients with GAAIH and patients with acute exacerbation of chronic AIH revealed that prothrombin activity (96% [74-100] vs. 61% [10-100]; p = 0.003) and albumin levels (3.9 ± 0.2 g/dL vs. 3.4 ± 0.5 g/dL; p < 0.001) were higher in patients with GAAIH. The International Autoimmune Hepatitis Group score was higher in patients with acute exacerbation of chronic AIH (18.5 [8-23] vs. 16.5 [15-17]; p = 0.010). Compared to 15.2% of acute exacerbation of chronic AIH, complete therapeutic response to treatment was achieved in 67.7% of cases with GAAIH (p = 0.018).

Conclusions

GAAIH was rare (8.3%), and patients with this presentation exhibited more preserved liver function tests, suggesting that most cases presenting with loss of function are acute exacerbation of chronic AIH. Additionally, patients with GAAIH had a better complete therapeutic response, suggesting a more preserved liver function at presentation, and early diagnosis has a positive therapeutic implication.

Histopathology and its clinical correlation of liver biopsy in patients with treated autoimmune hepatitis

The diagnosis of autoimmune hepatitis (AIH) relies on well-established criteria encompassing histological, serological, and clinical features. Diagnosing AIH may become challenging when encountering patients who have undergone steroid therapy for other co-existing diseases. Thirty-nine liver biopsies from 25 patients with treated and untreated AIH were classified into three groups: 1) Newly diagnosed untreated biopsies (n = 16); 2) Newly diagnosed partially treated biopsies from patients already on steroid treatment for other co-existing diseases (n = 9); 3) Previously diagnosed biopsies from patients who had undergone complete treatment (n = 14). In the untreated AIH group, at least 50 % of the cases exhibited the following features: at least moderate portal inflammation (81 %), at least moderate lobular inflammation (56 %), ductular reaction (94 %), inflammation gradient from bile duct to interface (88 %), unequivocal interface hepatitis (100 %), emperipolesis (56 %), plasma cell cluster (88 %), apoptosis or necrosis (63 %), pericentral inflammation (63 %), and periportal fibrosis (88 %). Although all these diagnostically sensitive histologic features were present in significantly fewer cases after treatment (p < 0.05), the features of ductular reaction, inflammation gradient from bile duct to interface, pericentral inflammation, and periportal fibrosis were likely to persist after treatment, especially in partially treated cases; these features did not show a significant association with higher transaminase levels (P > 0.05) and were considered as indirect features of hepatocytic injury. Our data suggest categorizing AIH histological features into direct and indirect hepatocytic injuries. Direct hepatocytic injury features significantly correlate with transaminase levels and respond well to treatment, while indirect ones show weaker transaminase correlation and relative treatment resistance.

Severe acute liver disease in adults: Contemporary role of histopathology

Liver biopsies have consistently contributed to our understanding of the pathogenesis and aetiologies of acute liver disease. As other diagnostic modalities have been developed and refined, the role of biopsy in the management of patients with acute liver failure (ALF), acute-on-chronic liver failure (ACLF) and acute hepatitis, including acute liver injury (ALI), has changed. Liver biopsy remains particularly valuable when first-line diagnostic algorithms fail to determine aetiology. Despite not being identified as a mandatory diagnostic tool in recent clinical guidelines for the management of ALF or ACLF, many centres continue to undertake biopsies given the relative safety of transjugular biopsy in this setting. Several studies have demonstrated that liver biopsy can provide prognostic information, particularly in the context of so-called indeterminate hepatitis, and is extremely useful in excluding conditions such as metastatic tumours that would preclude transplantation. In addition, its widespread use of percutaneous biopsies in cases of less severe acute liver injury, for example in the establishment of a diagnosis of acute presentation of autoimmune hepatitis or confirmation of a probable or definite drug-induced liver injury (DILI), has meant that many centres have seen a shift in the ratio of specimens they are receiving from patients with chronic to acute liver disease. Histopathologists therefore need to be equipped to deal with these challenging specimens. This overview provides an insight into the contemporary role of biopsies (as well as explant and autopsy material) in diagnosing acute liver disease. It outlines up-to-date clinical definitions of liver injury and considers recent recommendations for the diagnosis of AIH and drug-induced, autoimmune-like hepatitis (DI-AIH).

The etiology and differential diagnosis of "autoimmune hepatitis-like liver disease" in children: a single-center retrospective study

Background

Children with autoimmune hepatitis (AIH) often present with symptoms similar to those of other liver diseases. This study consists of a comparison between the clinical and histological characteristics of AIH and those of other four AIH-like liver diseases [i.e., drug-induced liver injury (DILI), gene deficiency, infectious liver disease and other etiology of liver disease], as well as an evaluation of the AIH scoring system's diagnostic performance.

Methods

All children with AIH-like liver disease at our center from January 2013 to December 2022 were included. The clinical and histological characteristics of the AIH group were retrospectively analyzed and compared with those of the other four groups.

Results

A total of 208 children were included and divided into AIH group (18 patients), DILI group (38 patients), gene deficiency group (44 patients), infectious liver disease group (74 patients), and other etiology group (34 patients). The antinuclear antibodies (ANA) ≥ 1:320 rate was significantly higher in the AIH compared to the other four groups after multiple testing correction (p < 0.0125), while patients with positive antibodies to liver-kidney microsomal-1 (anti-LKM1, n = 3) and smooth muscle antibodies (SMA, n = 2) were only observed in the AIH group. The positive rates of antibodies to liver cytosol type1 (anti-LC1) and Ro52 were higher than those in the other four groups. The serum immunoglobulin G (IgG) and globulin levels, as well as the proportions of portal lymphoplasmacytic infiltration, lobular hepatitis with more than moderate interface hepatitis, and lobular hepatitis with lymphoplasmacytic infiltration, were significantly higher in the AIH group than in the other four groups after multiple testing correction (p < 0.0125). The cirrhosis rate in the AIH group was higher than that in the DILI and infectious liver disease groups (p < 0.0125). Both the simplified (AUC > 0.73) and the revised systems (AUC > 0.93) for AIH have good diagnostic performance, with the latter being superior (p < 0.05).

Conclusion

Positive autoantibodies (ANA ≥ 1:320 or anti-LKM1 positive, or accompanied by SMA, anti-LC1 or Ro-52 positive) and elevated serum IgG or globulin levels contribute to early recognition of AIH. The presence of lobular hepatitis with more than moderate interface hepatitis and lymphoplasmacytic infiltration contribute to the diagnosis of AIH.

COVID-19 vaccine-induced liver injury

PURPOSE OF REVIEW

The rapid rollout and uptake of novel coronavirus disease 2019 (COVID-19) vaccines has been accompanied by a small yet noticeable accumulation of reports of liver injury occurring after vaccination. This review describes the present evidence surrounding COVID-19 vaccine-induced liver injury (VILI).

RECENT FINDINGS

Liver injury occurring after the COVID-19 vaccine often presents clinically similar to autoimmune hepatitis, with positive autoantibodies and a portal and lobular inflammatory infiltrate and varying degrees of necrosis on biopsy. The overwhelming majority of patients recover, often spontaneously or with a limited course of immunosuppression. The overall incidence of this phenomenon appears to be exceedingly low.

SUMMARY

Providers should remain vigilant for ongoing reports of VILI after COVID-19 and yet feel reassured by the low incidence and high likelihood of recovery. Ongoing genetic and histological study, as well as longer-term follow-up of presently identified cases, will shed further light on the clinical entity of VILI.

Autoimmune Hepatitis: A Diagnostic and Therapeutic Overview

Autoimmune hepatitis is an immune-mediated inflammatory condition of the liver of undetermined cause that affects both sexes, all ages, races, and ethnicities. Its clinical presentation can be very broad, from having an asymptomatic and silent course to presenting as acute hepatitis, cirrhosis, and acute liver failure potentially requiring liver transplantation. The diagnosis is based on histological abnormalities (interface hepatitis), characteristic clinical and laboratory findings (increased aspartate aminotransferase, alanine aminotransferase, and serum IgG concentration), and the presence of one or more characteristic autoantibodies. The large heterogeneity of these clinical, biochemical, and histological findings can sometimes make a timely and proper diagnosis a difficult task. Treatment seeks to achieve remission of the disease and prevent further progression of liver disease. First-line therapy includes high-dose corticosteroids, which are later tapered to decrease side effects, and azathioprine. In the presence of azathioprine intolerance or a poor response to the standard of care, second-line therapy needs to be considered, including mycophenolate mofetil. AIH remains a diagnostic and therapeutic challenge, and a further understanding of the pathophysiological pathways of the disease and the implementation of randomized controlled trials are needed.

Retrospective, single-center analysis of autoimmune hepatitis in Jordanian children: clinical features, treatments, and outcomes

OBJECTIVES

This study describes clinical, biochemical, and histological features and long-term outcomes in pediatric patients diagnosed with autoimmune hepatitis (AIH) at King Abdullah University Hospital, Jordan.

DESIGN

Retrospective, single-center study.

SETTING

King Abdullah University Hospital, Jordan.

PARTICIPANTS

Inclusion of all pediatric patients with AIH diagnosed at our hospital from 2015 to 2023. Exclusion criteria was patients aged over 18 at time of diagnosis and those diagnosed elsewhere.

OUTCOME MEASURES

Understanding clinical, biochemical, and histological AIH features in children, evaluating treatment responses, and reporting short- and long-term complications, including mortality.

RESULTS

Sixteen pediatric cases were diagnosed, with an average age of 9.84 ± 4.13 years. Females comprised 75% of patients, and 31.3% presented with acute liver failure. Jaundice was the most common symptom, and hepatosplenomegaly was observed in 18% of cases. Most patients had elevated transaminase levels, along with positive anti-smooth muscle antibody (ASMA) and antinuclear antibodies (ANA). Common hematological abnormalities included anemia (56.3%) and thrombocytopenia (37.5%). All patients underwent liver biopsy, with interface hepatitis present in 81.3% of cases. Treatment mainly involved prednisone and azathioprine. Three patients died, one discontinued therapy, two patients were lost to follow-up, and 10 remained on treatment.

CONCLUSION

Autoimmune hepatitis affects Jordanian children, primarily female children. Jaundice is the most common presenting symptoms. Only Type I AIH occurred in our cohort. Although of good response to conventional treatment with steroids and immunosuppression, mortality reached 18.8%.

Diagnosis of Autoimmune Hepatitis

Autoimmune hepatitis (AIH) presents a diagnostic challenge because it is relatively rare and heterogenous in presentation. This article presents the currently adopted approach to AIH diagnosis and explores the challenges with accurately identifying this disease entity. AIH offers no pathognomonic findings, instead relies on clinical presentation, serology, and histology to make the diagnosis. Diagnostic scoring systems support clinical judgment and serve as valuable tools in diagnosis and research. Histological analysis remains the cornerstone of diagnosis and to this day biopsy is essential to make the diagnosis.

Defining characteristics and long-term prognosis of drug-induced autoimmune-like hepatitis: A retrospective cohort study

BACKGROUND

Drug-induced autoimmune-like hepatitis (DI-AILH) is poorly defined and more data are required to better characterise and manage this disease entity.

OBJECTIVES

The aim of this study was to evaluate the clinical characteristics, histology and long-term outcomes of DI-AILH compared with idiopathic autoimmune hepatitis (AIH).

METHODS

This retrospective cohort study reviewed 28 DI-AILH and 39 AIH patients in a single centre. The new (2022) and simplified (2008) AIH histology criteria were used to assess DI-AILH.

RESULTS

DI-AILH were more likely to present with jaundice (p = 0.004) and higher bilirubin levels (p = 0.04) than AIH. AIH patients had higher rate of immunosuppression (IS) use including second- and third-line agents, though the time to reach biochemical remission were comparable. AIH patients had more advanced fibrosis than DI-AILH (Ishak fibrosis score 3.5 vs. 1.9, p < 0.0001). DI-AILH more commonly had eosinophilic aggregates (18% vs. 3%, p = 0.031) and less commonly showed plasma cell aggregates (61% vs. 97%, p < 0.001) than AIH. The simplified AIH histology criteria identified 1 atypical histology within the DI-AILH cohort, although this patient required long-term IS. The new AIH histology criteria classified 23 (82%) as likely AIH and 5 (18%) as possible AIH. Two of the possible DI-AILH did not require IS and one patient had successful IS withdrawal. Four DI-AILH patients with fibrosis stage ≤3 had successful IS withdrawal compared with none in the AIH group. Four patients underwent liver transplantation (LT) in both cohorts with significantly shorter time to LT in DI-AILH as the indication was for (sub)acute liver failure. Two DI-AILH patients died within 60 days of LT.

CONCLUSION

The new AIH histology criteria may be better at identifying DI-AILH. Immunosuppression withdrawal in those without significant fibrosis may be considered. DI-AILH is at risk of (sub)acute liver failure and early discussions with a transplant centre would be desirable.

Autoimmune Hepatitis: Pathophysiology

Genome-wide association analyses suggest that HLA genes including HLA-DRB*0301, HLA-DRB*0401, and HLA-B*3501 as well as non-HLA genes including CD28/CTLA4/ICOS and SYNPR increased AIH susceptibility. The destruction of hepatocytes is the result of the imbalance between proinflammatory cells and immunosuppressive cells, especially the imbalance between Tregs and Th17 cells. The microbiome in patients with AIH is decreased in diversity with a specific decline in Bifidobacterium and enrichment in Veillonella and Faecalibacterium. Recent evidence has demonstrated the pathogenic role of E. gallinarum and L.reuteri in inducing autoimmunity in the liver.

Autoimmune Hepatitis: From Evolution to Current Status-A Pathologist's Perspective

Autoimmune hepatitis (AIH) is a chronic, relapsing and remitting, immune-mediated liver disease that progresses to cirrhosis if left untreated. A significant number of patients may present with acute hepatitis or acute liver failure, which are often misdiagnosed as toxic liver injury. AIH shows a preponderance in young women but may be seen in children and the elderly. Diagnosis requires the integration of clinical, biochemical, and serologic parameters, along with supportive liver histology and exclusion of other causes of liver disease. Liver biopsy is a prerequisite for diagnosis of AIH, to assess severity and stage of disease, exclude other entities, and recognize any concurrent morbidities. No single biomarker or histologic feature is pathognomonic for AIH. The diagnostic and histologic criteria have undergone several modifications since the original scoring system was proposed by the International Autoimmune Hepatitis Group (IAIHG) in 1993. Recently, the IAIHG has proposed consensus recommendations for histologic criteria, relevant for both acute and chronic AIH. This review article will describe the evolving diagnostic criteria for AIH, with their limitations and utility, and with an emphasis on the role of liver histology in the diagnosis and management of AIH.

Incidence and predictors of hepatocellular carcinoma in patients with autoimmune hepatitis

BACKGROUND AND AIMS

Autoimmune hepatitis (AIH) is a rare chronic liver disease of unknown aetiology; the risk of hepatocellular carcinoma (HCC) remains unclear and risk factors are not well-defined. We aimed to investigate the risk of HCC across a multicentre AIH cohort and to identify predictive factors.

METHODS

We performed a retrospective, observational, multicentric study of patients included in the International Autoimmune Hepatitis Group Retrospective Registry. The assessed clinical outcomes were HCC development, liver transplantation, and death. Fine and Gray regression analysis stratified by centre was applied to determine the effects of individual covariates; the cumulative incidence of HCC was estimated using the competing risk method with death as a competing risk.

RESULTS

A total of 1,428 patients diagnosed with AIH from 1980 to 2020 from 22 eligible centres across Europe and Canada were included, with a median follow-up of 11.1 years (interquartile range 5.2-15.9). Two hundred and ninety-three (20.5%) patients had cirrhosis at diagnosis. During follow-up, 24 patients developed HCC (1.7%), an incidence rate of 1.44 cases/1,000 patient-years; the cumulative incidence of HCC increased over time (0.6% at 5 years, 0.9% at 10 years, 2.7% at 20 years, and 6.6% at 30 years of follow-up). Patients who developed cirrhosis during follow-up had a significantly higher incidence of HCC. The cumulative incidence of HCC was 2.6%, 4.6%, 5.6% and 6.6% at 5, 10, 15, and 20 years after the development of cirrhosis, respectively. Obesity (hazard ratio [HR] 2.94, p = 0.04), cirrhosis (HR 3.17, p = 0.01), and AIH/PSC variant syndrome (HR 5.18, p = 0.007) at baseline were independent risk factors for HCC development.

CONCLUSIONS

HCC incidence in AIH is low even after cirrhosis development and is associated with risk factors including obesity, cirrhosis, and AIH/PSC variant syndrome.

IMPACT AND IMPLICATIONS

The risk of developing hepatocellular carcinoma (HCC) in individuals with autoimmune hepatitis (AIH) seems to be lower than for other aetiologies of chronic liver disease. Yet, solid data for this specific patient group remain elusive, given that most of the existing evidence comes from small, single-centre studies. In our study, we found that HCC incidence in patients with AIH is low even after the onset of cirrhosis. Additionally, factors such as advanced age, obesity, cirrhosis, alcohol consumption, and the presence of the AIH/PSC variant syndrome at the time of AIH diagnosis are linked to a higher risk of HCC. Based on these findings, there seems to be merit in adopting a specialized HCC monitoring programme for patients with AIH based on their individual risk factors.

Prognostic models and autoimmune liver diseases

Autoimmune liver diseases (AILDs) are complex diseases with unknown causes and immune-mediated pathophysiology. In primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH) disease modifying drugs are available which improve patient quality and quantity of life. In primary sclerosing cholangitis (PSC) no medical therapy is available and the only accepted treatment is liver transplantation (LT). PBC, PSC and AIH possess features that describe the archetype of patients within each disorder. On the other hand, the classical disorders are not homogeneous, and patients within each diagnosis may present with a range of clinical, biochemical, serological, and histological findings. Singularly, they are considered rare diseases, but together, they account for approximately 20% of LTs in Europe and USA. Management of these patients is complex, as AILDs are relatively uncommon in clinical practice with challenges in developing expertise, disease presentation can be sneaky, clinical phenotypes and disease course are heterogeneous. Prognostic models are key tools for clinicians to assess patients' risk and to provide personalized care to patients. Aim of this review is to discuss challenges of the management of AILDs and how the available prognostic models can help. We will discuss the prognostic models developed in AILDs, with a special focus on the prognostic models that can support the clinical management of patients with AILDs: in PBC models based on ursodeoxycholic acid (UDCA) response and markers of liver fibrosis; in PSC several markers including biochemistry, disease stage and radiological semiquantitative markers; and finally in AIH, markers of disease stage and disease activity.

Morphologic and molecular analysis of liver injury after SARS-CoV-2 vaccination reveals distinct characteristics

BACKGROUND & AIMS

Liver injury after COVID-19 vaccination is very rare and shows clinical and histomorphological similarities with autoimmune hepatitis (AIH). Little is known about the pathophysiology of COVID-19 vaccine-induced liver injury (VILI) and its relationship to AIH. Therefore, we compared VILI with AIH.

METHODS

Formalin-fixed and paraffin-embedded liver biopsy samples from patients with VILI (n = 6) and from patients with an initial diagnosis of AIH (n = 9) were included. Both cohorts were compared by histomorphological evaluation, whole-transcriptome and spatial transcriptome sequencing, multiplex immunofluorescence, and immune repertoire sequencing.

RESULTS

Histomorphology was similar in both cohorts but showed more pronounced centrilobular necrosis in VILI. Gene expression profiling showed that mitochondrial metabolism and oxidative stress-related pathways were more and interferon response pathways were less enriched in VILI. Multiplex analysis revealed that inflammation in VILI was dominated by CD8+ effector T cells, similar to drug-induced autoimmune-like hepatitis. In contrast, AIH showed a dominance of CD4+ effector T cells and CD79a+ B and plasma cells. T-cell receptor (TCR) and B-cell receptor sequencing showed that T and B cell clones were more dominant in VILI than in AIH. In addition, many T cell clones detected in the liver were also found in the blood. Interestingly, analysis of TCR beta chain and Ig heavy chain variable-joining gene usage further showed that TRBV6-1, TRBV5-1, TRBV7-6, and IgHV1-24 genes are used differently in VILI than in AIH.

CONCLUSIONS

Our analyses support that SARS-CoV-2 VILI is related to AIH but also shows distinct differences from AIH in histomorphology, pathway activation, cellular immune infiltrates, and TCR usage. Therefore, VILI may be a separate entity, which is distinct from AIH and more closely related to drug-induced autoimmune-like hepatitis.

IMPACT AND IMPLICATIONS

Little is known about the pathophysiology of COVID-19 vaccine-induced liver injury (VILI). Our analysis shows that COVID-19 VILI shares some similarities with autoimmune hepatitis, but also has distinct differences such as increased activation of metabolic pathways, a more prominent CD8+ T cell infiltrate, and an oligoclonal T and B cell response. Our findings suggest that VILI is a distinct disease entity. Therefore, there is a good chance that many patients with COVID-19 VILI will recover completely and will not develop long-term autoimmune hepatitis.

Clinicopathologic Features of Severe Acute Hepatitis Associated With Adenovirus Infection in Children

A recent increase in reports of severe acute hepatitis of unknown etiology in children is under investigation. Although adenovirus has been frequently detected, its role remains unclear, and systematic histopathologic analysis is lacking. We conducted a retrospective study of 11 children hospitalized between October 2021 and May 2022 with unexplained acute hepatitis and concurrent adenovirus infection. Liver biopsies collected shortly after admission demonstrated moderately to severely active hepatitis in 8/11 (73%) cases, characterized by marked portal mixed inflammation, moderate-to-severe interface activity, and milder lobular inflammation. Clusters of plasma cells were present in 6/11 (55%) cases, mimicking autoimmune hepatitis. Semiquantitative scoring of 17 discrete histologic features found that greater degrees of portal inflammation, interface activity, bile duct injury, bile ductular reaction, lobular inflammation, Kupffer cell activation, and hepatocyte focal necrosis were significantly more common in these cases in comparison to the control group of unexplained acute severe hepatitis without adenovirus infection. Liver biopsy immunohistochemistry was negative for adenovirus in all cases. Polymerase chain reaction testing of liver tissue was positive for the enteric adenovirus serotypes 41 (species F) in 10/11 (91%) cases. An immunoprofile study of hepatic infiltrating lymphocytes in 1 patient revealed the presence of large numbers of CD3 + and CD4 + lymphocytes. Nine patients received supportive treatment without steroids and recovered without the need for liver transplantation. In summary, liver injury in children with severe acute hepatitis and adenovirus infection is characterized by a hepatitic pattern that resembles severe autoimmune hepatitis and may represent an immune-mediated process associated with viral infection.

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.

Juvenile Autoimmune Hepatitis: Recent Advances in Diagnosis, Management and Long-Term Outcome

Juvenile autoimmune hepatitis (JAIH) is severe immune-mediated necro-inflammatory disease of the liver with spontaneous progression to cirrhosis and liver failure if left untreated. The diagnosis is based on the combination of clinical, laboratory and histological findings. Prothrombin ratio is a useful prognostic factor to identify patients who will most likely require a liver transplant by adolescence or early adulthood. JAIH treatment consists of immune suppression and should be started promptly at diagnosis to halt inflammatory liver damage and ultimately prevent fibrosis and progression to end-stage liver disease. The risk of relapse is high especially in the setting of poor treatment compliance. Recent evidence however suggests that treatment discontinuation is possible after a prolonged period of normal aminotransferase activity without the need for liver biopsy prior to withdrawal.

[Autoimmune hepatitis : From autoantibodies to cirrhosis]

Autoimmune Hepatitis (AIH) is an immune-mediated liver disease of unknown origin. Its clinical presentation is heterogeneous and ranges from asymptomatic courses over several years to acute forms with acute liver failure. Accordingly, the diagnosis is only made at the stage of cirrhosis in about one third of affected individuals. Early diagnosis and a consistent, adequate, individualized, immunosuppressive therapy are crucial for the prognosis, which is excellent when treated properly. AIH is rare in the general population and can be easily overlooked due to its variable clinical picture and sometimes difficult diagnosis. AIH should be considered as a differential diagnosis in any unclear acute or chronic hepatopathy. The therapy initially consists of remission induction and subsequently maintenance therapy with (often lifelong) immunosuppressants.

Baseline Predictors of the Long-Term Insufficient Biochemical Response in Patients with Autoimmune Hepatitis: A Single Center Experience

The treatment response criteria in autoimmune hepatitis (AIH) have been recently updated. This study aimed to assess treatment responses in 39 (16 males) patients with AIH confirmed by histology. Prednisone added to azathioprine or mycophenolate was the most frequent first-line treatment. Serum alanine aminotransferase (ALT) levels were periodically checked for a median of 45 months. Eight (20.5%) patients presented 4 weeks non-response (NR). Baseline lower multiples of ALT above the upper normal limit (UNL) (p = 0.005), Ishak liver fibrosis score > 3 (p = 0.029), and less frequent confluent necrosis > 2 (p < 0.001) were independent predictors of NR. 24 (61.5%) patients achieved complete biochemical response (CBR) at six months. Ishak liver fibrosis score ≤ 3 (p < 0.001), lobular eosinophilic infiltrate (p < 0.001), and ≥50% decrease in serum ALT levels at week 4 (p < 0.001) were independent predictors of CBR. In addition, the GLUCRE score, derived from the multiplication of serum creatinine (mg/dL) and glucose (mg/dL) levels, were identified. A baseline GLUCRE value > 100 strongly predicted CBR failure (p = 0.003) at a follow-up greater than 12 months. In conclusion, the absence of cirrhosis and a ≥50% UNL decrease in serum ALT levels were independent predictors for CBR. A baseline GLUCRE score may help identify patients maintaining longer CBR.

Autoimmune hepatitis and eosinophilia: A rare case report

BACKGROUND

Autoimmune hepatitis consists of a chronic liver disease whose etiology is unknown. It is comprised of relevant immunological aspects and of immune-mediated liver injury. Eosinophilia may be a considerable feature, particularly happening in male patients.

CASE SUMMARY

We report here a Crohn´s disease patient presenting with de novo hypergammaglobulinemia, circulating autoantibodies and elevated transaminase levels. He also had significant peripheral eosinophilia and elevated immunoglobulin E levels at diagnosis. The pathology findings from liver biopsy were compatible with autoimmune hepatitis with eosinophilic infiltration.

CONCLUSION

This is the first report of autoimmune hepatitis with exuberant eosinophilic infiltration in the liver and bone marrow, described in a patient with Crohn’s disease.

[Treatment of Autoimmune Hepatitis]

Autoimmune hepatitis (AIH) is a chronic liver disease, characterized by elevated levels of transaminases, immunoglobulin G, and positive autoantibodies. The disease course is dynamic and presents heterogeneous disease manifestations at diagnosis. This review summarizes the issues regarding the treatment and monitoring of AIH in adult patients. Glucocorticoids and azathioprine are the first line of treatment. Alternative first-line treatments include budesonide or mycophenolate mofetil (MMF). Although no randomized controlled trials have been performed, MMF, cyclosporine, tacrolimus, 6-mercaptopurine, 6-thioguanine, allopurinol, sirolimus, everolimus, infliximab, or rituximab have been attempted in patients not responding to or intolerant to first-line treatments. Most patients require life-long special monitoring, with or without maintenance treatment.

[Diagnosis of Autoimmune Hepatitis]

Autoimmune hepatitis (AIH) is an immune-mediated inflammatory liver disease with an uncertain cause. The diagnosis of AIH is based on the characteristic clinical and laboratory findings (elevated liver enzyme and hypergammaglobulinemia), the presence of characteristic autoantibodies, and compatible histological abnormalities. AIH lacks a signature diagnostic marker, and the diagnosis requires the exclusion of other diseases (viral hepatitis, alcoholic liver disease, non-alcoholic steatohepatitis, drug-induced liver injury, Wilson's disease, and hereditary hemochromatosis). Therefore, collaboration between the clinical physician, laboratory medicine experts, and pathologists is important for a diagnosis. In December 2022, the Korean Association for the Study of the Liver (KASL) clinical practice guidelines were established. This review article summarizes the diagnosis part of these guidelines.

Diagnosis and management of autoimmune hepatitis

Autoimmune hepatitis is an inflammatory disease of the liver of unknown cause that may progress to liver cirrhosis and end stage liver failure if diagnosis is overlooked and treatment delayed. The clinical presentation is often that of acute hepatitis, sometimes very severe; less frequently, it can be insidious or completely asymptomatic. The disease can affect people of any age and is more common in women; its incidence and prevalence seem to be on the rise worldwide. An abnormal immune response targeting liver autoantigens and inducing persistent and self-perpetuating liver inflammation is the pathogenic mechanism of the disease. A specific set of autoantibodies, increased IgG concentrations, and histological demonstration of interface hepatitis and periportal necrosis are the diagnostic hallmarks of autoimmune hepatitis. Prompt response to treatment with corticosteroids and other immunomodulatory drugs is almost universal and supports the diagnosis. The aims of treatment are to induce and maintain long term remission of liver inflammation. Treatment can often even reverse liver fibrosis, thus preventing progression to advanced cirrhosis and its complications. Most patients need lifelong maintenance therapy, and repeated follow-up in experienced hands improves the quality of care and quality of life for affected patients.

The many faces and pathologic diagnostic challenges of autoimmune hepatitis

Autoimmune hepatitis (AIH) is an immune-mediated chronic inflammatory liver disease, characterized by hypergammaglobulinemia, the presence of specific autoantibodies, and typical abnormalities in liver histology. Prompt diagnosis and initiation of immunosuppressive treatment are necessary for both chronic and acute onset AIH to prevent progression to end-stage liver disease or fatal liver failure. However, the diagnosis of AIH is challenging mainly because of its heterogeneous clinical, serological and pathological features. Although portal lymphoplasmacytosis and interface hepatitis are the most typical histological features of AIH, many other histological features can be observed in AIH, including emperipolesis, hepatocyte rosettes, and Kupffer cell hyaline globules. Recent studies have questioned emperipolesis and hepatocyte rosette formation as typical features of AIH, and atypical clinical and histological presentations have also been recognized. This led an international working group to propose the modified AIH diagnostic criteria. However, it is well recognized that there are no pathognomonic characteristics that can be used to diagnose AIH and careful clinicopathological correlation is required to arrive at the correct diagnosis. The aim of this review is to summarize the histological features of AIH, its varied histopathologic spectrum, recent updates and major differential diagnoses in routine clinical practice.

Autoimmune serology testing in clinical practice: An updated roadmap for the diagnosis of autoimmune hepatitis

Diagnosis of autoimmune hepatitis (AIH) is in most cases challenging for clinicians as there is not a single specific laboratory or histological marker to diagnose or exclude the presence of the disease. The clinical spectrum of AIH varies from completely asymptomatic to acute-severe or even rarely fulminant hepatic failure, while everybody can be affected irrespective of age, gender, and ethnicity. The old revised and the newer simplified diagnostic scores have been established by the International Autoimmune Hepatitis Group (IAIHG) in 1999 and 2008, respectively, which are based on several clinical, laboratory and histological parameters. Additionally, a thorough differential diagnosis from other diseases mimicking AIH is absolutely indicated. In this context, autoantibodies detection in patients with suspected AIH is mandatory -even though not pathognomonic- not only for AIH diagnosis but furthermore, for AIH classification (AIH-type 1 and AIH-type 2). Although autoimmune serology can be supportive of AIH diagnosis in ≥95% of cases if testing has been performed according to the IAIHG guidelines, this is not the case under real-life circumstances in routine clinical laboratories. Clinicians should be careful both for the importance of the required testing and how to interpret the results and therefore, they should communicate and discuss with the laboratory personnel to achieve the maximum benefit for the patient. Herein, a detailed and updated review of the diagnostic work-up for AIH diagnosis under real-life conditions is given to minimize the underestimation and misdiagnosis of AIH which can result in progression of the disease and unfavourable outcomes.

The Ultrastructure of Hepatic Stellate Cell-Macrophage Intercellular Crosstalk as a New Morphological Insight into Phenomenon of Fibrogenesis in Pediatric Autoimmune Hepatitis

The aim of the study was the pioneering retrospective ultrastructural evaluation of respective forms of hepatic stellate cells (HSCs) and analysis of their crosstalk with other adjacent nonparenchymal cells (NPCs), especially Kupffer cells/macrophages (KCs/MPs), in pediatric autoimmune hepatitis (AIH).

METHODS

Ultrastructural assessment of the HSC population and NPCs was performed in transmission electron microscopy (TEM) using pretreatment liver biopsies from 25 children (8 boys and 17 girls) aged 4-17 with clinic-pathologically diagnosed untreated AIH.

RESULTS

Submicroscopic evaluation allowed easy identification of numerous HSCs in the form of transitory cells, i.e., T-HSCs, accompanied by signs of fibrosis. T-HSCs included cells with features of activation initiation (iHSCs) and activation perpetuation (pHSCs), indicating high HSC activation plasticity. The pHSCs were markedly elongated and mainly showed a distinct loss of lipid cytoplasmic material, expanded and dilated channels of granular endoplasmic reticulum, and linear bundles of microfilaments beneath the cell membrane. They were surrounded by usually mature collagen fibers. Frequently activated KCs/MPs adhered directly to T-HSCs. Between them, tight intercellular junctions were formed by means of point desmosomes.

CONCLUSIONS

Our qualitative TEM observations indicate a key role of T-HSCs in liver fibrogenesis in pediatric AIH, with the essential involvement of activated KCs/MPs that directly adhere to them. Tight intercellular junctions, being the ultrastructural exponent of the specific cellular mechanisms of the crosstalk between NPCs, can play a vital role in hepatic collagen fibroplasia. A better understanding of HSC population morphology at the ultrastructural level in AIH seems important not only to improve the disease morphological diagnostics but to also provide new insights into therapeutic interventions for the phenomenon of liver fibrogenesis.

Thirty-two years' experience of treating fulminant hepatitis in a Japanese single center

AIM

The prognosis of patients with acute liver failure has improved dramatically in the past three decades due to advances in medical critical care and use of liver transplantation (LT) in Western countries, where the etiology of acute liver failure is different from that in Japan. We analyzed patients with fulminant hepatitis (FH) and late-onset hepatic failure (LOHF) admitted to our unit over a 32-year period to clarify the nature of Japanese patients with FH and LOHF.

METHODS

A total of 137 Japanese patients with FH and LOHF between 1986 and 2017 were analyzed for etiologies, disease types, treatment protocols, and outcome.

RESULTS

Of 137 patients, 124 were FH (53 acute type and 71 subacute type) and 13 LOHF. The major etiology was due to viral infections in 48% of patients. A total of 23.4% of patients recovered without LT, 7.3% received LT, and 69.3% died without LT. The number of patients showed rise and fall without an evident decrease during the period. Patients with autoimmune hepatitis increased after the establishment of autoimmune hepatitis criteria in 1999 (p < 0.001), and that with indeterminate cause decreased (p < 0.01). The mean age was older in the last decade than in the first decade (p = 0.036). Spontaneous and overall survival rates were not different during the period.

CONCLUSIONS

The prognosis of our patients with FH and LOHF has not improved, probably because of aging and the increasing proportion of etiologies with poor prognosis and difficult-to-treat patients without response to medications regardless of advancement of clinical management, including artificial liver support devices and LT.

Role of triglycerides as a predictor of autoimmune hepatitis with cirrhosis

Background

Metabolism-related indicators have been suggested as possible prognostic indicators of liver disease in recent relevant studies, but their value in predicting autoimmune hepatitis (AIH) cirrhosis is unclear. This study evaluated the role of lipid levels in determining the prognosis of AIH-related cirrhosis.

Methods

We retrospectively included 345 patients with AIH who were initially diagnosed at Beijing Ditan Hospital from 2010-2019, and ultimately screened 196 patients who met the criteria. A logistic regression analysis was performed to screen factors associated with cirrhosis. Kaplan–Meier (KM) curves were constructed to analyze the effects of different triglyceride (TG) levels on the survival of patients with cirrhosis. A restricted cubic spline fitted Cox regression model was used to analyze the nonlinear relationship between serum TG levels and patient prognosis.

Results

Patients with AIH cirrhosis have lower TG levels than those without cirrhosis. Lower serum TG levels correlated with the severity of cirrhosis. The survival analysis showed that TG levels were associated with the overall survival of patients with AIH, as a lower 5-year survival rate (log-rank P<0.05) was observed for patients in the TG≤0.95 mmol/L group (hazard ratio (HR)=3.79, 95% CI: 1.528-9.423). In addition, lower TG levels were associated with a higher incidence of death in patients with AIH cirrhosis. The risk of death gradually increased for the interval of TG levels of 0.5-0.8 mmol/L (P for nonlinearity<0.001), and the hazard ratio per standard deviation increase in the TG level was 0.97 (95% CI: 0.94-0.99). The plot showed a U-shaped relationship between TG levels and the survival of patients with decompensated cirrhosis. The risk ratio progressively decreased with lower TG levels (P for nonlinearity=0.002). Below 0.6 mmol/L, the probability of TG risk per standard deviation prediction was 1.49 (95% CI: 1.00-2.24).

Conclusion

Serum TG levels are closely related to the disease severity and overall survival of patients with AIH cirrhosis and may be used as a new indicator of advanced liver disease and long-term prognosis.

Reproducibility and Feasibility of Classification and National Guidelines for Histological Diagnosis of Canine Mammary Gland Tumours: A Multi-Institutional Ring Study

Simple Summary

Tumours of the mammary gland are common in humans, as in canine species. They are very heterogenous with numerous morphological variants and different biologic behaviours. In the last few decades, several efforts have been made to classify these tumours histologically and establish the level of malignancy by using histologic grading systems. However, reproducibility and diagnostic agreement of such classification and grading have been only rarely assessed. In this study, we tested the variability in diagnoses performed by 15 pathologists using the same classification and grading system. Prior to the study, pathologists agreed on guidelines regarding how to apply these systems. Pathologists worked blindly on 36 digital histologic slides of canine mammary tumours. The agreement was statistically analysed using Cohen’s kappa coefficient that, when equal to 1, indicates perfect agreement. The overall agreement in the identification of hyperplastic-dysplastic/benign/malignant lesions was substantial (kappa 0.76), while outcomes on morphological classification had only a moderate agreement (k = 0.54). Tumour grade assigned by pathologists was the least concordant and kappa could not be calculated. Although promising, the results underline that each diagnostic/grading system should be assessed and optimized for standardization and high diagnostic agreement.

Abstract

Histological diagnosis of Canine Mammary Tumours (CMTs) provides the basis for proper treatment and follow-up. Nowadays, its accuracy is poorly understood and variable interpretation of histological criteria leads to a lack of standardisation and impossibility to compare studies. This study aimed to quantify the reproducibility of histological diagnosis and grading in CMTs. A blinded ring test on 36 CMTs was performed by 15 veterinary pathologists with different levels of education, after discussion of critical points on the Davis-Thompson Foundation Classification and providing consensus guidelines. Kappa statistics were used to compare the interobserver variability. The overall concordance rate of diagnostic interpretations of WP on identification of hyperplasia-dysplasia/benign/malignant lesions showed a substantial agreement (average k ranging from 0.66 to 0.82, with a k-combined of 0.76). Instead, outcomes on ICD-O-3.2 morphological code /diagnosis of histotype had only a moderate agreement (average k ranging from 0.44 and 0.64, with a k-combined of 0.54). The results demonstrated that standardised classification and consensus guidelines can produce moderate to substantial agreement; however, further efforts are needed to increase this agreement in distinguishing benign versus malignant lesions and in histological grading.

Histopathologist and clinician interface in diagnosis and management of autoimmune hepatitis

Diagnosis of AIH is based on a combination of clinical, laboratory and histological information. It has been formalised by diagnostic scoring systems, to which liver biopsy contributes substantially. Diagnostic biopsy is thus, desirable in nearly all patients. An adequate biopsy size, provision by clinicians of adequate information to histopathologists and active discussion at regular meetings are all important for accurate histological diagnosis. Recently, the specificity of some features previously thought to suggest AIH has been questioned, and new recommendations for histological diagnosis have been proposed, although not yet validated. The histology of acutely presenting AIH and that of severe or fulminant AIH include some characteristic features. Primary biliary cholangitis, primary sclerosing cholangitis and non-alcoholic fatty liver disease may co-exist with AIH on biopsy. Liver biopsy also enables grading of severity of inflammation and staging of fibrosis. Presence of cirrhosis is a poor prognostic marker. Repeat liver biopsy after achieving biochemical remission, although not performed routinely, enables assessment of (a) histological remission, a favourable prognostic indicator and (b) fibrosis progression. It can thus help determine further management.