Autoimmune Hepatitis: Serum Autoantibodies in Clinical Practice

From Multiple Sclerosis to Organ-Specific Autoimmune Disorders: Insights into the Molecular and Clinical Implications of Comorbidity

Multiple sclerosis (MS) is a complex autoimmune disorder that affects the central nervous system. Although the pathological mechanisms of MS have been extensively studied, its association with other autoimmune diseases, known as comorbidities, remains unclear. In this comprehensive review article, we aim to clarify the cellular and molecular relationship between MS and the incidence of organ-specific autoimmune comorbidities by summarizing former studies. We will explore the commonalities and possible differences between the immune response mechanisms in MS and other autoimmune diseases and provide an overview of the current understanding of the pathophysiological processes involved in the co-occurrence of MS and other organ-specific autoimmune comorbidities. Through this review, we aim to contribute to the development of effective therapeutic strategies that can improve the quality of life of MS patients with comorbidities.

Autoimmune-Like Hepatitis Related to SARS-CoV-2 Vaccination: Towards a Clearer Definition

Vaccines are the most effective tool against COVID-19 and are generally safe. Very rare and heterogeneous cases of acute liver injury associated to all types of SARS-CoV-2 vaccines have been reported, mostly with autoimmune features. Epidemiological studies used heterogeneous diagnostic criteria and included different populations. Immunological studies in selected cases of acute liver injury linked to mRNA SARS-CoV-2 vaccines suggest that it has a unique pathophysiology, the vaccine-encoded spike protein playing a central role in triggering the aberrant immune response. In most series, liver injury was observed more often following the second vaccine dose. Latency from vaccination to the diagnosis of hepatitis was 1-147 days after the last vaccine dose. Raised immunoglobulin G levels and positive anti-nuclear and/or anti-smooth muscle antibodies are frequent. The vast majority of reported cases have been treated with corticosteroids, mostly associated with azathioprine. Outcome is generally favourable, but cases requiring liver transplantation or causing death have been reported. The heterogeneous clinical entity of acute liver injury linked to SARS-CoV-2 vaccines includes patients requiring long-term immunosuppression, similarly to autoimmune hepatitis, and patients with self-limiting liver damage, possibly representing a unique form of autoimmune-like hepatitis, which we suggest being referred to as SARS-CoV-2 vaccine-associated liver injury (SVALI). Further studies are needed to investigate the pathogenic mechanisms related to the immune response to the spike viral protein in the liver.

Diagnosis and Treatment of Patients with Autoimmune Hepatitis (Experts’ Agreement)

Background. In the last decade, the understanding of the pathogenesis of autoimmune hepatitis (AIH) has significantly deepened, based on the results of new clinical studies some diagnostic issues have been revised and immunosuppressive therapy regimens have been optimized.Materials and methods. The latest Russian clinical guidelines for the diagnosis and treatment of AIH were presented in 2013; and in 2017, the first Russian agreement on the diagnosis and treatment of AIH was held. Updating approaches to the management of patients with AIH necessitated next systematization for use in clinical practice. In February 2024, the final session was held to discuss the provisions of the second agreement on the diagnosis and treatment of AIH.Results. This publication presents the main discussion points of the agreement regarding methods and algorithms for detecting autoantibodies, the role of liver biopsy, revised morphological criteria for AIH, optimized immunosuppressive therapy regimens, updated criteria for assessing the response to therapy.Conclusions. The agreement was the result of the work of a group of experts on the diagnosis and treatment of AIH and represents the basis for the creation of updated federal clinical guidelines.

Immune-mediated liver injury caused by immune checkpoint inhibitors exhibits distinct clinical features that differ from autoimmune hepatitis

BACKGROUND

Immune-mediated liver injury caused by immune checkpoint inhibitors (ILICI) and autoimmune hepatitis (AIH) are both related to the distorted immune system. However, ILICI differs from AIH in several distinct ways. We aimed to study the differences between ILICI and AIH.

RESEARCH DESIGN AND METHODS

This is a retrospective study collecting clinical data of ILICI (2016.1-2024.2) and AIH (2002.1-2023.6) patients. Demographic, clinicopathological, radiological characteristics, treatment and outcomes were analyzed.

RESULTS

A total of 71 ILICI and 158 AIH cases were included. ILICI group had older patients and fewer females (age: 66 vs. 56 years, gender: 28.2% vs. 85.4%, p < 0.001). They had lower ALT, AST, TBil, IgG levels, and lower titers of ANA. Some ILICI patients exhibited bile duct edema and dilation, while AIH patients typically had liver fibrosis in CT/MRI. Histologically, ILICI showed bile duct injury, inflammatory cells infiltration with fewer plasma cells. Glucocorticoid treatment was less common, but ALT level recovery was faster in ILICI patients (41 vs. 140 days, p < 0.001).

CONCLUSIONS

ILICI generally affects older patients without a female predilection and is linked to milder, acute liver injury. High ANA titers, elevated IgG, and prominent plasma cell infiltration were less common. Liver function normalizes more quickly in ILICI.

Role of microbiome in autoimmune liver diseases

The microbiome plays a crucial role in integrating environmental influences into host physiology, potentially linking it to autoimmune liver diseases, such as autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. All autoimmune liver diseases are associated with reduced diversity of the gut microbiome and altered abundance of certain bacteria. However, the relationship between the microbiome and liver diseases is bidirectional and varies over the course of the disease. This makes it challenging to dissect whether such changes in the microbiome are initiating or driving factors in autoimmune liver diseases, secondary consequences of disease and/or pharmacological intervention, or alterations that modify the clinical course that patients experience. Potential mechanisms include the presence of pathobionts, disease-modifying microbial metabolites, and more nonspecific reduced gut barrier function, and it is highly likely that the effect of these change during the progression of the disease. Recurrent disease after liver transplantation is a major clinical challenge and a common denominator in these conditions, which could also represent a window to disease mechanisms of the gut-liver axis. Herein, we propose future research priorities, which should involve clinical trials, extensive molecular phenotyping at high resolution, and experimental studies in model systems. Overall, autoimmune liver diseases are characterized by an altered microbiome, and interventions targeting these changes hold promise for improving clinical care based on the emerging field of microbiota medicine.

Easy recognition and high autoimmune hepatitis specificity of smooth muscle antibodies giving an actin microfilament immunofluorescent pattern on embryonal vascular smooth muscle cells

Smooth muscle antibodies (SMA) with anti-microfilament actin (MF-SMA) specificity are regarded as highly specific markers of type 1 autoimmune hepatitis (AIH-1) but their recognition relying on immunofluorescence of vessel, glomeruli, and tubules (SMA-VGT pattern) in rodent kidney tissue, is restricted by operator-dependent interpretation. A gold standard method for their identification is not available. We assessed and compared the diagnostic accuracy for AIH-1 of an embryonal aorta vascular smooth muscle (VSM) cell line-based assay with those of the rodent tissue-based assay for the detection of MF-SMA pattern in AIH-1 patients and controls. Sera from 138 AIH-1 patients and 295 controls (105 primary biliary cholangitis, 40 primary sclerosing cholangitis, 50 chronic viral hepatitis, 20 alcohol-related liver disease, 40 steatotic liver disease, and 40 healthy controls) were assayed for MF-SMA and SMA-VGT using VSM-based and rodent tissue-based assays, respectively. MF-SMA and SMA-VGT were found in 96 (70%) and 87 (63%) AIH-1 patients, and 2 controls (P < 0.0001). Compared with SMA-VGT, MF-SMA showed similar specificity (99%), higher sensitivity (70% vs 63%, P = ns) and likelihood ratio for a positive test (70 vs 65). Nine (7%) AIH-1 patients were MF-SMA positive despite being SMA-VGT negative. Overall agreement between SMA-VGT and MF-SMA was 87% (kappa coefficient 0.870, [0.789-0.952]). MF-SMA were associated with higher serum γ-globulin [26 (12-55) vs 20 g/l (13-34), P < 0.005] and immunoglobulin G (IgG) levels [3155 (1296-7344) vs 2050 mg/dl (1377-3357), P < 0.002]. The easily recognizable IFL MF-SMA pattern on VSM cells strongly correlated with SMA-VGT and has an equally high specificity for AIH-1. Confirmation of these results in other laboratories would support the clinical application of the VSM cell-based assay for reliable detection of AIH-specific SMA.

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.

Autoimmune hepatitis presenting as severe anemia

Autoimmune hepatitis (AIH) is relatively rare in children. Herein, our case demonstrates a unique presentation of AIH in a previously healthy 18-year-old female presenting with a mild cough, fatigue, and severe anemia (hemoglobin 2.9 g/dL). Initial evaluation revealed jaundice and scleral icterus, prompting transfer of care and further testing, which demonstrated severe microcytic anemia, pancytopenia, elevated liver enzymes, direct hyperbilirubinemia, and marked splenomegaly. Concern for autoimmune hemolytic anemia resulted in a delayed diagnosis. The combination of triple antibody positivity (anti-nuclear antibodies, anti-actin, and anti-liver-kidney microsomal-1) and liver histology findings confirmed the diagnosis of AIH. Intravenous methylprednisolone was initiated to induce remission. Due to pancytopenia and persistently elevated international normalized ratio, tacrolimus was chosen as the maintenance immunosuppression instead of azathioprine. This case highlights several significant considerations for clinicians, including the importance of a timely clinicopathologic diagnosis, the severe anemia presentation secondary to hypersplenism, and the rare finding of triple autoantibody-positive 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.

Distinct subsets of anti-pulmonary autoantibodies correlate with disease severity and survival in severe COVID-19 patients

Autoantibodies targeting the lung tissue were identified in severe COVID-19 patients in this retrospective study. Fifty-three percent of 104 patients developed anti-pulmonary antibodies, the majority of which were IgM class, suggesting that they developed upon infection with SARS-CoV-2. Anti-pulmonary antibodies correlated with worse pulmonary function and a higher risk of multiorgan failure that was further aggravated if 3 or more autoantibody clones were simultaneously present (multi-producers). Multi-producer patients were older than the patients with less or no autoantibodies. One of the identified autoantibodies (targeting a pulmonary protein of ~ 50 kDa) associated with worse clinical outcomes, including mortality. In summary, severe COVID-19 is associated with the development of lung-specific autoantibodies, which may worsen the clinical outcome. Tissue proteome-wide tests, such as the ones applied here, can be used to detect autoimmunity in the post-COVID state to identify the cause of symptoms and to reveal a new target for treatment.

Autoimmune hepatitis: Brighton Collaboration case definition and guidelines for data collection, analysis, and presentation of immunisation safety data

This report introduces a Brighton Collaboration (BC) case definition for autoimmune hepatitis (AIH), which has been classified as a priority adverse event of special interest (AESI), as there were possible cases seen following COVID-19 vaccination. The case definition was developed by a group of subject matter and BC process experts to facilitate safety data comparability across pre- and post-licensure clinical trials, as well as pharmacovigilance activities in multiple settings with diverse resources and healthcare access. The usual BC case definition development process was followed in an expedited manner, and took two months to complete, including finalising the manuscript for publication, instead of the usual 1 year development time. It includes a systematic review of the literature and an expert consensus to define levels of diagnostic certainty for AIH, and provides specific guidelines for data collection and analysis. Histology, serological and biochemical tests and exclusion of alternate diagnosis were considered necessary to define the levels of certainty (definitive, probable and possible). AEFI reports of suspected AIH were independently classified by the WG members to test its useability and these classifications were used to finalise the case definition. The document underwent peer review by external AIH experts and a Reference Group of vaccine safety stakeholders in high-, low- and middle-income countries to ensure case definition useability, applicability, and scientific integrity. The expedited process can be replicated for development of other standardised case definitions for priority AESIs for endemics and epidemics. While applicable to cases reported following immunisation, the case definition is independent of lapsed time following vaccination and, as such, can also be used to determine background incidence for vaccinated and unvaccinated control groups in studies of causal association. While use of this case definition is also appropriate for the study of safety of other products including drugs, it is not meant to guide clinical case management.

Autoimmune Hepatitis: Epidemiology, Subtypes, and Presentation

Autoimmune hepatitis (AIH) is a chronic immunologic disorder in which the immune system targets the liver. The disease has a genetic basis and this accounts for the epidemiologic variation observed in serologic testing and clinical presentation across different populations. The incidence of AIH increases with age into the 70s and seems to be increasing in prevalence. Most patients test positive for antinuclear antibody, ASMA, or anti-LKM but about 20% of patients do not have these serologic markers. At clinical presentation, patients may be asymptomatic, symptomatic, have acute liver failure, or decompensated cirrhosis.

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.

Chronic Liver Disease, Not Everything Is What It Seems: Autoimmune Hepatitis/Primary Biliary Cholangitis Overlap Syndrome

Overlap syndrome (OS) is a rare condition that shares characteristics of at least two other recognized diseases, whose early diagnosis impacts treatment decisions and prognosis since the unfavorable course of the OS seems to be worse than that of the diseases alone. OS in autoimmune liver diseases combines characteristic features of autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis. AIH is a chronic, inflammatory disease of the liver that occurs predominantly in females. The disease may start as acute hepatitis and progress to chronic liver disease and cirrhosis. PBC is characterized by a T-lymphocyte-mediated attack on small intralobular bile ducts. A continuous assault on the bile duct epithelial cells leads to their gradual destruction and eventual disappearance. The sustained loss of intralobular bile ducts causes the signs and symptoms of cholestasis and eventually may result in cirrhosis and liver failure. With treatment with ursodeoxycholic acid, the majority of patients now have normal life expectancies. The authors report a subtype of OS, i.e., AIH-PBC overlap, characterized by elevated serum transaminases, cholestasis markers, antimitochondrial antibodies (AMAs), and histological findings compatible with AIH, including moderate-to-severe interface hepatitis. The authors present a clinical case referred for internal medicine consultation regarding a 73-year-old woman presenting pancytopenia and increased transaminases, along with weight loss, decreased appetite, and tiredness. Laboratory tests were positive for the following parameters: antinuclear antibody, anti-double-stranded DNA antibody, AMA, anti-glycoprotein-210, and anti-smooth muscle antibody (anti-actin). Computed tomography of the abdomen displayed chronic liver disease and evidence of small perihepatic ascites. The diagnosis was established with a liver biopsy revealing architectural alteration with severe advanced fibrosis, with bridges and parenchymal nodularity, and histological parenchymal changes of progressive chronic liver disease (chronic biliary disease/PBC) in the stage of cirrhosis. With proper treatment, the condition of the patient significantly improved.

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.

Evaluation of immunoserological detection of anti-liver kidney microsomal, anti-soluble liver antigen and anti-mitochondrial antibodies

Autoantibodies are the diagnostic hallmark of autoimmune liver diseases. Indirect immunofluorescence (IFT) is the reference method for the detection of anti-mitochondrial antibodies (AMA) and anti-liver kidney microsomal type-1 (anti-LKM1) antibodies, and inhibition ELISA (iELISA) for anti-soluble liver antigen (anti-SLA) antibodies. Given the complexity of these techniques, commercial ELISAs have emerged as a practical alternative, but without head-to-head validations. This study evaluated the agreement between three commercial ELISAs and the reference techniques and the impact of polyreactive immunoglobulin G (pIgG), a recently described phenomenon in autoimmune hepatitis, on commercial ELISAs. Inter-rater reliability was assessed using Cohen-Kappa coefficient (κ). Forty-eight, 46, and 66 samples were analyzed for AMA, anti-LKM1, and anti-SLA, respectively. For AMA, one commercial assay showed high agreement (κ = 0.91 (0.78-1.00)) with the reference method, while the other two showed weak or moderate agreement. For anti-LKM1, only one commercial assay showed high agreement (κ = 0.86 (0.71-1.0)). For anti-SLA antibodies only moderate agreement was achieved (κ up to 0.71 (0.52-0.89)). There was a trend towards higher pIgG levels in false-positives in the commercial ELISAs. Patients with high suspicion of autoimmune liver diseases should be referred to reference laboratories with the capacity of performing gold standard methods if the initial ELISA-based screening was performed.

Non-organ-specific autoantibodies with unspecific patterns are a frequent para-infectious feature of chronic hepatitis D

Infections with hepatotropic viruses are associated with various immune phenomena. Hepatitis D virus (HDV) causes the most severe form of viral hepatitis. However, few recent data are available on non-disease-specific and non-organ-specific antibody (NOSA) titers and immunoglobulin G (IgG) levels in chronic hepatitis D (CHD) patients. Here, we examined the NOSA titers and IgG levels of 40 patients with CHD and different disease courses and compared them to 70 patients with chronic hepatitis B (CHB) infection. 43% of CHD patients had previously undergone treatment with pegylated interferon-α (IFN-α). The antibody display of 46 untreated patients diagnosed with autoimmune hepatitis (AIH) was used as a reference. The frequency of elevated NOSA titers (CHD 69% vs. CHB 43%, p < 0.01), and the median IgG levels (CHD 16.9 g/L vs. CHB 12.7 g/L, p < 0.01) were significantly higher in CHD patients than in patients with CHB, and highest in patients with AIH (96%, 19.5 g/L). Also, the antinuclear antibody pattern was homogeneous in many patients with AIH and unspecific in patients with viral hepatitis. Additionally, f-actin autoantibodies were only detectable in patients with AIH (39% of SMA). In CHD patients, IgG levels correlated with higher HDV viral loads, transaminases, and liver stiffness values. IgG levels and NOSA were similar in CHD patients irrespective of a previous IFN-α treatment. In summary, autoantibodies with an unspecific pattern are frequently detected in CHD patients with unclear clinical relevance.

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

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

[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.

Reliability and reproducibility of antinuclear antibody testing in pediatric rheumatology practice

Antinuclear antibody (ANA) testing is common practice among health care practitioners when evaluating children and adolescents with non-specific symptoms including fatigue and aches and pains. When positive, ANA results often lead to referrals to pediatric rheumatologists as these antibodies may be key indicators for specific pediatric rheumatologic diagnoses. The reliability and reproducibility of ANA tests varies with assay techniques and validation and interpretation of results. In the following article, review of ANA testing in pediatrics is provided along with case examples that demonstrate the reliability and reproducibility of these results in specific scenarios common in the practice of pediatric rheumatology. Guidelines for more accurate utilization of ANA testing are presented with the aim to improve testing and interpretation by ordering clinicians.

Interference of Antinuclear Antibody (ANA) in Indirect Immunofluorescence Assay (IIFA)-Based Perinuclear Antineutrophil Cytoplasmic Antibody (pANCA) Interpretation

Background

Indirect immunofluorescence assay (IIFA) based on antineutrophil cytoplasmic antibody (ANCA) testing is a commonly employed test for diagnosing autoimmune vasculitis. Antinuclear antibody (ANA) can give rise to a false interpretation of perinuclear-ANCA (pANCA) in ethanol-fixed granulocyte substrates. Analytical interference could frequently occur in setups where ethanol-fixed substrates are used alone. Here, we intend to investigate this ANA interference in pANCA interpretation.

Methods

In this retrospective study, we studied anti-MPO-negative but ANA-positive and pANCA (IIFA based) samples. We also correlated immunoblot results (where data were available) and checked the association between grades of blot positivity (an indicator of the concentration of ANA) and frequency of pANCA interpretation. Data were analyzed by appropriate statistical techniques (Chi-square and kappa statistics).

Results

About 19.2% of ANA blot (ENA-blot) positive samples displayed a pANCA positive pattern in the ethanol-fixed substrate, while this positivity in ENA-blot negatives was 6.5%. In positive ANA-IIFA samples, about 14.7% yielded pANCA patterns (on ethanol fixed substrates). Out of this, nuclear homogenous pattern yielding samples gave the highest frequency pANCA, that is, in 31.5% followed by speckled (11.1%), DFS (10.3%), and centromere (6.7%).The association of the nuclear homogenous pattern was statistically significant.

Conclusions

ANA-positive results may interfere with the interpretation of pANCA as observed in ANA-IIFA and ENA-blot positive samples. ANA-IIFA patterns like nuclear homogenous may strongly associate this pANCA interpretation. This can help laboratories perform ANCA testing more effectively, ruling out ANA interference in ANCA screening.

B cells in autoimmune hepatitis: bystanders or central players?

B cells are central for the adaptive immune system to mount successful immune responses not only as antibody producers but also as regulators of cellular immunity. These multifaceted features are also reflected in autoimmunity where autoreactive B cells can fuel disease by production of cytotoxic autoantibodies, presentation of autoantigens to autoreactive T cells, and secretion of cytokines and chemokines that either promote detrimental immune activation or impair regulatory T and B cells. The role of B cells and autoantibodies in autoimmune hepatitis (AIH) have been controversially discussed, with typical autoantibodies and hypergammaglobulinemia indicating a key role, while strong HLA class II association suggests T cells as key players. In this review, we summarize current knowledge on B cells in AIH and how different B cell subpopulations may drive AIH progression beyond autoantibodies. We also discuss recent findings of B cell-directed therapies in AIH.