Intrahepatic IgG/IgM plasma cells ratio helps in classifying autoimmune liver diseases

Heterogeneity of antibody-secreting cells infiltrating autoimmune tissues

The humoral response is frequently dysfunctioning in autoimmunity with a frequent rise in total serum immunoglobulins, among which are found autoantibodies that may be pathogenic by themselves and/or propagate the inflammatory reaction. The infiltration of autoimmune tissues by antibody-secreting cells (ASCs) constitutes another dysfunction. The known high dependency of ASCs on the microenvironment to survive combined to the high diversity of infiltrated tissues implies that ASCs must adapt. Some tissues even within a single clinical autoimmune entity are devoid of infiltration. The latter means that either the tissue is not permissive or ASCs fail to adapt. The origin of infiltrated ASCs is also variable. Indeed, ASCs may be commonly generated in the secondary lymphoid organ draining the autoimmune tissue, and home at the inflammation site under the guidance of specific chemokines. Alternatively, ASCs may be generated locally, when ectopic germinal centers are formed in the autoimmune tissue. Alloimmune tissues with the example of kidney transplantation will also be discussed own to their high similarity with autoimmune tissues. It should also be noted that antibody production is not the only function of ASCs, since cells with regulatory functions have also been described. This article will review all the phenotypic variations indicative of tissue adaptation described so for at the level of ASC-infiltrating auto/alloimmune tissues. The aim is to potentially define tissue-specific molecular targets in ASCs to improve the specificity of future autoimmune treatments.

IgG and IgM Immunohistochemistry in Primary Biliary Cholangitis (PBC) and Autoimmune Hepatitis (AIH) Liver Explants

OBJECTIVES

Primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH) can be difficult to distinguish in end-stage liver disease. Previous studies have shown that immunoglobulin G (IgG) and immunoglobulin M (IgM) immunostaining can differentiate AIH from PBC in needle core biopsy specimens, and we seek to extend these data to cirrhotic liver explants, in which the histology of AIH or PBC may be indiscernible.

METHODS

Clinical data were reviewed for 20 patients with PBC cirrhosis and 16 with AIH cirrhosis. Immunohistochemistry for IgM and IgG was performed on representative blocks of explanted livers. Three high-power fields with the highest concentration of IgG- and IgM-positive plasma cells were counted and compared.

RESULTS

The average number of IgM-positive plasma cells was significantly higher in PBC explants (7.3) than in AIH (1.8) (P = .001). There was no significant difference in the average number of IgG-positive plasma cells in PBC (2.5) and AIH (2.8) (P = .8). The IgG/IgM ratio was more likely to be less than 1.0 in PBC (17/20, 85%) compared with AIH (7/16, 44%) (P = .01).

CONCLUSIONS

Our study demonstrates that the absolute number of IgM plasma cells is greater in explants of cirrhotic PBC compared with AIH. These findings may be helpful in the evaluation of cryptogenic cirrhosis.

Diagnostic and prognostic scoring systems for autoimmune hepatitis: a review

INTRODUCTION

Auto-immune hepatitis (AIH) is a rare condition which primarily affects young women. Several diagnostic scoring systems exist based on clinical, biochemical, immunologic and histologic characteristics of AIH. Additionally, prognostic parameters can be identified. The purpose of this literature review is to compare the clinical value, strengths and limitations of these diagnostic and prognostic scoring systems.

METHODS

A literature search was performed in two databases and selected based on diagnostic and prognostic criteria. Only studies concerning AIH in adults were included.

RESULTS

The backbone of scoring systems remains the revised AIH criteria published in 1999 and the simplified from 2008. The revised system shows a higher sensitivity, lower specificity and lower diagnostic accuracy compared to the simplified. Limitations to these scoring systems include limited diagnostic accuracy in acute or fulminant liver failure, insufficient inclusion of atypical auto-antibodies and lacking diagnostic power in presence of overlap syndromes. Concerning these overlap syndromes, the Paris criteria show a higher diagnostic accuracy compared to the scoring systems for AIH. Presently, no clinical prognostic scoring systems are available. However, a first system based on response to treatment accurately predicts long-term survival in AIH.

CONCLUSION

Diagnostic scoring systems are useful in diagnosing AIH and have complementary value. However, they are no substitute for the gold standard of appropriate clinical assessment and are mostly useful in defining cohorts for research purposes. An evolution towards a more dynamic scoring system, using prognostic parameters and the progression of typical features, seems more valuable than the current diagnostic systems.

IgG:IgM Ratios of Liver Plasma Cells Reveal Similar Phenotypes of Primary Biliary Cholangitis With and Without Features of Autoimmune Hepatitis

Within the spectrum of autoimmune liver diseases, there are patients who manifest features of more than one disease, which was previously identified as having overlap syndrome^1,2 and is now referred to as variant syndromes. The most common variant syndrome is between primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH). Typically, AIH presents with elevated serum immunoglobulin (Ig) G, whereas PBC is associated with elevated serum IgM.^3,4 Previous studies have suggested that plasma cells in liver biopsies of AIH patients are predominantly IgG+, whereas in PBC, there is an abundance of IgM+ cells.^5,6 We wanted to determine the immunostaining pattern for IgG and IgM of liver plasma cells among Hispanic patients in Los Angeles with features of both PBC-AIH compared with those with PBC or AIH alone.

Gut and Liver B Cells of Common Clonal Origin in Primary Sclerosing Cholangitis-Inflammatory Bowel Disease

B cells express an antigen‐specific B‐cell receptor (BCR) and may contribute to liver inflammation by recognizing shared antigens in the gut and liver. Herein, we used high‐throughput BCR sequencing of the immunoglobulin heavy chain, specifically the complementarity‐determining region 3 (CDR3), to characterize the B‐cell repertoire of freshly‐frozen paired gut and liver tissue samples from patients with primary sclerosing cholangitis (PSC) and concurrent inflammatory bowel disease (IBD) (PSC‐IBD, n = 10) and paired formalin‐fixed paraffin‐embedded (FFPE) tumor‐adjacent normal colon and liver tissue from patients with colorectal liver metastases (controls, n = 10). We observed significantly greater numbers of B cells (P < 0.01) and unique B‐cell clonotypes (P < 0.05) in gut samples compared to liver samples of patients with PSC‐IBD, whereas BCR sequences in FFPE normal gut and liver samples were nearly absent (14 ± 5 clonotypes; mean ± SD; n = 20). In PSC‐IBD, an average of 8.3% (range, 1.6%‐18.0%) of B‐cell clonotypes were found to overlap paired gut and liver samples following the exclusion of memory clonotypes reported in the blood of healthy controls. Overlapping gut and liver clonotypes showed stronger evidence of antigen‐driven activation compared to non‐overlapping clonotypes, including shorter CDR3 lengths and higher counts of somatic hypermutation (P < 0.0001). Conclusion: A proportion of gut and liver B cells originate from a common clonal origin (i.e., likely to recognize the same antigen) in patients with PSC which suggests B‐cell antigens are shared across the gut–liver axis. (Hepatology Communications 2018; 00:000‐000)

The utility of IgG, IgM, and CD138 immunohistochemistry in the evaluation of autoimmune liver diseases

Primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH) present with distinct clinical features. The term "PBC-AIH overlap syndrome (OS)" has been adopted to describe the condition characterized by occurrence of both PBC and AIH, although this clinical entity is difficult to define. This study aimed to assess the utility of IgG, IgM, and CD138 immunohistochemistry in the evaluation of AIH, PBC, and OS. Immunohistochemistry was performed with anti-human IgG, IgM, and CD138 to detect specific plasma cells in the liver. Predominant IgG staining was observed in AIH (85.7 %), while equivocal (46.1 %) or predominant (38.5 %) IgM staining was observed in PBC. In OS, equivocal (20 %) or predominant (80 %) IgG staining was observed. The IgM/IgG ratio was significantly higher in PBC than in AIH or OS (P < 0.005). Histological findings revealed significantly higher IgM expression in PBC at cholangitis activity grades 2-3 compared to those at cholangitis activity grades 0-1. In contrast, a significantly higher IgG expression was observed in PBC at hepatitis activity and fibrosis grades 2-3 compared to those at hepatitis activity and fibrosis grades 0-1. Taken together, periportal plasmacytic infiltrates with variable immunohistochemistry patterns of IgG and IgM expression characterized different autoimmune liver diseases.

Clinicopathological study of primary biliary cirrhosis with interface hepatitis compared to autoimmune hepatitis

AIM: To investigate histological and immunohistochemical differences in hepatitis between autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC) with AIH features.

METHODS: Liver needle biopsies of 41 PBC with AIH features and 43 AIH patients were examined. The activity of periportal and lobular inflammation was scored 0 (none or minimal activity) to 4 (severe), and the degree of hepatitic rosette formation and emperipolesis was semiquantatively scored 0-3. The infiltration of mononuclear cells positive for CD20, CD38, CD3, CD4, and CD8 and positive for immunoglobulins (IgG, IgM, and IgA) at the periportal areas (interface hepatitis) and in the hepatic lobules (lobular hepatitis) were semiquantitatively scored in immunostained liver sections (score 0-6). Serum aspartate aminotransferase (AST), immunoglobulins, and autoantibodies at the time of liver biopsy were correlated with the histological and immunohistochemical scores of individual lesions.

RESULTS: Lobular hepatitis, hepatitic rosette formation, and emperipolesis were more extensive and frequent in AIH than in PBC. CD3+, CD4+, and CD8+ cell infiltration scores were higher in the hepatic lobules and at the interface in AIH but were also found in PBC. The degree of mononuclear cell infiltration correlated well with the degree of interface and lobular hepatitis in PBC, but to a lesser degree in AIH. CD20+ cells were mainly found in the portal tracts and, occasionally, at the interface in both diseases. Elevated AST correlated well with the hepatocyte necroinflammation and mononuclear cell infiltration, specifically CD38+ cells in PBC. No correlation existed between autoantibodies and inflammatory cell infiltration in PBC or AIH. While most AIH cases were IgG-predominant at the interface, PBC cases were divided into IgM-predominant, IgM/IgG-equal, and IgG-predominant types, with the latter sharing several features with AIH.

CONCLUSION: These results suggest that the hepatocellular injuries associated with interface and lobular hepatitis in AIH and PBC with interface hepatitis may not be identical.

Review article: autoimmune hepatitis -- current management and challenges

BACKGROUND

Autoimmune hepatitis (AIH) is a disease of unknown aetiology characterised by interface hepatitis, hypergammaglobulinaemia, circulating autoantibodies and a favourable response to immunosuppression.

AIM

To review recent advancements in understanding aetiopathogenesis, clinical, serological and histological features, diagnostic criteria and treatment strategies of AIH.

METHODS

Published studies on AIH extracted mainly from PubMed during the last 15 years.

RESULTS

Autoimmune hepatitis has a global distribution affecting any age, both sexes and all ethnic groups. Clinical manifestations are variable ranging from no symptoms to severe acute hepatitis and only seldom to fulminant hepatic failure. Autoimmune attack is perpetuated, possibly via molecular mimicry mechanisms, and favoured by the impaired control of regulatory T-cells. A typical laboratory finding is hypergammaglobulinaemia with selective elevation of IgG, although in 15-25% of patients - particularly children, elderly and acute cases - IgG levels are normal. Liver histology and autoantibodies, although not pathognomonic, still remain the hallmark for diagnosis. Immunosuppressive treatment is mandatory and life-saving; however, to meet strict response criteria, the conventional therapy with prednisolone with or without azathioprine is far from ideal.

CONCLUSIONS

Autoimmune hepatitis remains a major diagnostic and therapeutic challenge. The clinician, the hepato-pathologist and the laboratory personnel need to become more familiar with different expressions of the disease, interpretation of liver histology and autoimmune serology. According to the strict definition of treatment response issued by the 2010 AASLD guidelines, many patients are nonresponders to conventional treatment. Newer immunosuppressive agents targeting pathogenetic mechanisms can improve patient management, which needs to be tailored on a case-by-case basis.

Autoimmune Hepatitis

Autoimmune hepatitis is a chronic necroinflammatory disease of unknown etiology that is characterized by increased aminotransferases, serum autoantibodies, increased immunoglobulin G levels, and histological interface hepatitis. The disease does not have a pathognomonic clinical, laboratory, or histological feature; diagnosis depends on a combination of clinical and pathologic criteria which also form the basis for a weighted scoring system to aid diagnosis. Liver biopsy is an essential part of the diagnostic criteria and is also crucial to the management of the disease. This review focuses on the diagnosis, microscopic features, differential diagnosis and overlap syndromes of autoimmune hepatitis.

Primary biliary cirrhosis and hereditary hemorrhagic telangiectasia: When two rare diseases coexist

Primary biliary cirrhosis is a slowly progressive cholestatic autoimmune liver disease that mainly affects middle-aged women with an estimated prevalence ranging from 6.7 to 402 cases per million. Hereditary hemorrhagic telangiectasia, or Rendu-Osler-Weber disease, is an autosomal dominant disorder characterized by angiodysplastic lesions (telangiectases and arteriovenous malformations) that can affect many organs, including liver, with a prevalence of 1-2 cases per 10000. We describe the coexistence, for the first time to our knowledge, of these two rare diseases in a 50-year old Caucasian woman. In this setting, the relevance of an accurate medical history, the role of liver histology and the characterization of liver involvement through dynamic imaging techniques can be emphasized.

The overlap syndromes of autoimmune hepatitis

Autoimmune hepatitis has two major variant phenotypes in which the features of classical disease are co-mingled with those of primary biliary cirrhosis or primary sclerosing cholangitis. These overlap syndromes lack codified diagnostic criteria, established pathogenic mechanisms, and confident management strategies. Their clinical importance relates mainly to the identification of patients who respond poorly to conventional corticosteroid treatment. Scoring systems that lack discriminative power have been used in their definition, and a clinical phenotype based on pre-defined laboratory and histological findings has not been promulgated. The frequency of overlap with primary biliary cirrhosis is 7-13 %, and the frequency of overlap with primary sclerosing cholangitis is 8-17 %. Patients with autoimmune hepatitis and features of cholestatic disease must be distinguished from patients with cholestatic disease and features of autoimmune hepatitis. Variants of the overlap syndromes include patients with small duct primary sclerosing cholangitis, antimitochondrial antibody-negative primary biliary cirrhosis, autoimmune sclerosing cholangitis, and immunoglobulin G4-associated disease. Conventional corticosteroid therapy alone or in conjunction with ursodeoxycholic acid (13-15 mg/kg daily) has been variably effective, and cyclosporine, mycophenolate mofetil, and budesonide have been beneficial in selected patients. The key cholestatic features that influence the prognosis of autoimmune hepatitis must be defined and incorporated into the definition of the syndrome rather than rely on designations that imply the co-mingling of different diseases with manifestations of variable clinical relevance. The overlap syndromes in autoimmune hepatitis are imprecise, heterogeneous, and unfounded, but they constitute a clinical reality that must be accepted, diagnosed, refined, treated, and studied.

Diagnosis and treatment of autoimmune hepatitis

Autoimmune hepatitis is a chronic liver disease characterized by elevated aminotransferase levels, autoantibodies, increased γ-globulin or IgG levels and biopsy evidence of interface hepatitis. Recent advances include new practice guidelines that redefine criteria for remission to require complete biochemical and histological normalization on therapy; comparisons between the revised original and simplified diagnostic scoring systems; refined characterization of autoantibodies and their diagnostic performance parameters; proof of the safety and efficacy of combination budesonide and azathioprine therapy for non-cirrhotic patients; scrutiny of overlap syndromes; further analyses of the outcomes of orthotopic liver transplantation and the diagnosis and treatment of recurrent and de novo autoimmune hepatitis after transplantation. Anticipated consequences of the application of the new definition of therapeutic remission include a reduction in the proportion of patients achieving remission with conventional immunosuppression regimens and a corresponding increase in the need for alternative therapies.

Antimitochondrial antibody -M2 positive autoimmune hepatitis during standard of care for chronic hepatitis C

The current standard of care (SoC) for chronic hepatitis C, i.e. the combination of a pegylated-interferon (PEG-IFN) with ribavirin (RBV), may activate underlying autoimmune conditions. Particularly, interferon (IFN) has been known to induce or exacerbate autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC) in hepatitis C virus patients. We describe a severe, acute-onset antimitochondrial antibody (AMA)-M2 positive AIH appearing during the last weeks of SoC in a woman with chronic hepatitis C and no previous history of autoimmunity, and resolving on protracted steroids. In this context, the relevance of the characterization of the immunoglobulin isotype of portal plasma cells for a more appropriate diagnosis of autoimmune liver diseases can be emphasized.

Low incidence of positive smooth muscle antibody and high incidence of isolated IgM elevation in Chinese patients with autoimmune hepatitis and primary biliary cirrhosis overlap syndrome: a retrospective study

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BACKGROUND

Up to now, few data are available regarding the clinical characteristics of autoimmune hepatitis and primary biliary cirrhosis overlap syndrome. The study was to investigate and analyze the prevalent and clinical features of Chinese patients with this disease.

METHODS

Clinical data on patients diagnosed as autoimmune hepatitis and primary biliary cirrhosis overlap syndrome in our hospital from January 2001 to December 2006 were collected and analyzed.

RESULTS

Overlap syndrome of autoimmune hepatitis and primary biliary cirrhosis accounted for 10.33% of patients with autoimmune liver diseases during the past six years. For these patients with overlap syndrome, xanthochromia, lethargy and anorexia were the predominant complaints; a low incidence (14/146) of smooth muscle antibody positivity and a high incidence (37/89) of isolated IgM elevation were the main serological characteristics.

CONCLUSIONS

Overlap syndrome of autoimmune hepatitis and primary biliary cirrhosis was not rare in Chinese patients with clinical manifests of autoimmune liver diseases. Overlap of the diseases should not be disregarded when isolated IgM elevation was exhibited, and smooth muscle antibody might have little diagnostic significance in the overlap syndrome. If it was difficult to make a definite diagnosis, liver biopsy was necessary.

The liver in celiac disease: clinical manifestations, histologic features, and response to gluten-free diet in 30 patients

Descriptive reports of liver histologic features in celiac disease (CD) are sparse, and the effect of a gluten-free diet (GFD) on the course of liver injury is poorly understood. We reviewed liver biopsy specimens in 30 patients with CD and performed immunostains for IgG, IgG4, IgM, and IgA. Subsequent liver biochemical tests and compliance with the GFD were recorded. Of the patients, 19 had autoimmune-mediated liver disease (AILD; autoimmune hepatitis, 9; primary sclerosing cholangitis, 7; and primary biliary cirrhosis, 3). The remaining 11 patients had cryptogenic hepatitis (5), hepatitis C (2), steatohepatitis (2), sarcoidosis (1), and T-cell lymphoma (1). The liver disease diagnosis preceded the CD diagnosis in all groups except steatohepatitis. Although 82% of patients without AILD had symptomatic CD, only 26% of patients with AILD had such symptoms. The pathology of the specific liver disease was not atypical in histologic features or IgG/IgM ratios. While GFD improved cryptogenic hepatitis, it did not seem to affect AILD. We propose that AILD and cryptogenic hepatitis in patients with CD represent distinct clinical, histologic, and immunohistochemical entities rather than 2 ends of a spectrum of liver injury.

Hepatobiliary pathology

PURPOSE OF REVIEW

Recent studies pertaining to the histopathology of the liver and biliary tract are reviewed.

RECENT FINDINGS

Several studies are reviewed which describe the histologic features and clinical behavior of 'plasma cell hepatitis' in the posttransplant setting. Cytokeratin 7, EMA, and CD68 were found to be useful immunohistochemical stains in fibrolamellar hepatocellular carcinoma and may aid in the distinction between this variant and classic hepatocellular carcinoma. Arginase-1, another immunohistochemical stain, was found to have improved sensitivity over HepPar-1 in the diagnosis of classic hepatocellular carcinoma. Metabolic syndrome is common in children with nonalcoholic fatty liver disease and may be an indicator of more severe disease activity and fibrosis. Histologic features were described that may aid in the distinction between the steroid-responsive IgG4-associated cholangitis and the steroid-nonresponsive primary sclerosing cholangitis. In addition, immunohistochemical stains for IgM and IgG may be helpful in distinguishing between autoimmune liver diseases, with primary biliary cirrhosis and its antimitochondrial-negative variant, autoimmune cholangitis, being the two autoimmune liver diseases with a predominance of IgM-positive plasma cells.

SUMMARY

Several informative studies pertaining to hepatobiliary pathology were published this year, with topics including posttransplant plasma cell hepatitis, familial hemophagocytic lymphohistiocytosis, pediatric nonalcoholic fatty liver disease, and the use of immunohistochemical stains specific for various immunoglobulin subtypes.