Overlap syndromes of autoimmune hepatitis: what is known so far

The pattern of some autoimmune hepatitis can be difficult to classify, sometimes due to the overlap of these with primary biliary cirrhosis, primary sclerosing cholangitis and chronic viral hepatitis. The etiology of these variant forms remains unclear. The distinction among the overlap syndromes poses different problems both of prognosis and therapeutic approach. Presently, the utility of the scoring system devised and revised by the International Autoimmune Hepatitis Group regarding these cases is under discussion. Histological examination seems to be an important tool, but often the result does not help in defining a correct diagnosis. To date, the overlap syndromes can be classified at an intermediate level between cholestatic forms of autoimmune hepatitis or hepatic forms of cholestatic syndromes, but it cannot be excluded that the syndromes represent independent disorders.     

Overlap syndrome of primary biliary cirrhosis and autoimmune hepatitis with unusual initial presentation as fulminant hepatic failure

Autoimmune hepatitis and primary biliary cirrhosis are generally easy to discriminate on the basis of clinical, laboratory, and histological findings. The presence of anti-mitocondrial antibodies seropositivity and cholestatic clinical, laboratory, and/or histological features in patients with autoimmune hepatitis indicates the overlap syndrome of autoimmune hepatitis and primary biliary cirrhosis. Fulminant hepatic failure is an unusual initial form of presentation of autoimmune hepatitis and primary biliary cirrhosis overlap syndrome. We report the case of a 50-year-old woman with autoimmune hepatitis and primary biliary cirrhosis overlap syndrome who presented with fulminant hepatic failure. Fulminant hepatic failure has a high mortality rate and may require liver transplant. Our patient revealed a good response to corticosteroid and ursodeoxycholic acid therapy. It is important to identify and distinguish autoimmune hepatitis and variant syndromes from other forms of liver disease because of response to corticosteroid therapy.     

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.     

Overlap syndromes among autoimmune liver diseases

The three major immune disorders of the liver are autoimmune hepatitis（AIH）,primary biliary cirrhosis（PBC） and primary sclerosing cholangitis（PSC）.Variant forms of these diseases are generally called overlap syndromes,although there has been no standardised definition.Patients with overlap syndromes present with both hepatitic and cholestatic serum liver tests and have histological features of AIH and PBC or PSC.The AIH-PBC overlap syndrome is the most common form,affecting almost 10% of adults with AIH or PBC.Single cases of AIH and autoimmune cholangitis（AMA-negative PBC） overlap syndrome have also been reported.The AIH-PSC overlap syndrome is predominantly found in children,adolescents and young adults with AIH or PSC.Interestingly,transitions from one autoimmune to another have also been reported in a minority of patients,especially transitions from PBC to AIH-PBC overlap syndrome.Overlap syndromes show a progressive course towards liver cirrhosis and liver failure without treatment.Therapy for overlap syndromes is empiric,since controlled trials are not available in these rare disorders.Anticholestatic therapy with ursodeoxycholic acid is usually combined with immunosuppressive therapy with corticosteroids and/or azathioprine in both AIH-PBC and AIH-PSC overlap syndromes.In end-stage disease,liver transplantation is the treatment of choice.     

Overlap syndromes

In hepatology, the term overlap syndrome describes variant forms of the major hepatobiliary autoimmune diseases, autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC). Patients with overlap syndromes present with both hepatitic and cholestatic biochemical and histological features of AIH, PBC, and/or PSC, and usually show a progressive course toward liver cirrhosis and liver failure without adequate treatment. AIH-PBC overlap syndromes have been reported in almost 10% of adults with AIH or PBC, whereas AIH-PSC overlap syndromes were found in 6 to 8% of children, adolescents, and young adults with AIH or PSC. A minority of patients may also show transition from stable PBC to AIH, AIH to PBC, or AIH to PSC, as documented by single case reports and small case series. Single cases of AIH and autoimmune cholangitis (antimitochondrial antibody-negative PBC) overlap have also been reported. Empiric medical treatment of AIH-PBC and AIH-PSC overlap syndromes includes anticholestatic therapy with ursodeoxycholic acid and immunosuppressive therapy with corticosteroids and azathioprine. In end-stage disease, liver transplantation is the treatment of choice.     

Type II Autoimmune Hepatitis and Small Duct Sclerosing Cholangitis in a Seven Years Old Child: An Overlap Syndrome?

Introduction

Autoimmune hepatitis is an inflammatory disease with multifactorial ethiopatogenesis, characterized by lympho-monocytic infiltration of liver, presence of serum autoantibodies (ANA, SMA, LKM-1) and high levels of immunoglobulins. Overlap syndromes are defined as the association of autoimmune hepatitis with cholestatic diseases such as primary biliary cirrhosis and primary sclerosing cholangitis. The boundaries of these syndromes as distinct pathological entities are still matter of debate and they could be part of a major liver autoimmune disease. Furthermore, cholestatic diseases may present even with atypical features (AMA-negative primary cirrohosis, primary sclerosing cholangitis with normal cholangiography).

Case Presentation

We herein describe a case of a 7 year-old child affected by an overlap syndrome between type 2 autoimmune hepatitis and small duct primary sclerosing cholangitis. Although characterized by a severe onset, the disease showed a good response to treatment with prednisone and azathioprine.

Conclusions

The association of type 2 autoimmune hepatitis and small duct primary cholangitis has been rarely reported in literature and this report adds new data on this still unclear entity.     

Overlap syndromes: the International Autoimmune Hepatitis Group (IAIHG) position statement on a controversial issue

Some patients present with overlapping features between disorders within the spectrum of autoimmune liver diseases (i.e. autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC)) and are commonly classified as having an "overlap syndrome". Standardized definitions of "overlap syndromes" are lacking. The aim of this report by the International Autoimmune Hepatitis Group (IAIHG) is to evaluate if there are important reasons to classify conditions with overlapping features between autoimmune liver diseases as separate diagnostic entities. Definition of diagnostic criteria for overlap conditions can only be arbitrary. The IAIHG scoring system for diagnosis of AIH has been widely used to diagnose "overlap syndromes", but was not intended for such use and has not proven to be an efficient tool for this purpose. Some patients with overlapping features between a cholestatic and hepatitic disorder appear to benefit from treatment with a combination of ursodeoxycholic acid and immunosuppressants, but this strategy is not evidence-based, and it seems unjustified to define new diagnostic groups in this regard. The IAIHG suggests that patients with autoimmune liver disease should be categorized according to the predominating feature(s) as AIH, PBC, and PSC/small duct PSC, respectively, and that those with overlapping features are not considered as being distinct diagnostic entities. The IAIHG scoring system should not be used to establish subgroups of patients. Patients with PBC and PSC with features of AIH should be considered for immunosuppressive treatment. Due to the low prevalence of such "overlap syndromes", prospective interventional therapeutic trials cannot be expected in the foreseeable future.     

Overlap Syndromes of Autoimmune Hepatitis: An Open Question

The headword “overlap syndromes” of liver diseases includes the coexistence of autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis. These syndromes often represent a diagnostic and therapeutic challenge for hepatologists; it remains unclear whether these overlap syndromes form distinct entities or they are only variants of the major autoimmune liver diseases. The most frequent reported association occurs between autoimmune hepatitis and primary biliary cirrhosis, whereas the overlap between autoimmune hepatitis and primary sclerosing cholangitis is less frequent, typically at young age and often attendant with an inflammatory bowel disease. The choice therapy is based on ursodeoxycholic acid and immunosuppressive drugs, used at the same time or consecutively, according to the course of disease. The diagnostic scores for autoimmune hepatitis can help for diagnosis, even though their definitive soundness is lacking.     

Autoimmune liver disease - are there spectra that we do not know?

Autoimmune liver diseases (AILDs) are common leading causes for liver cirrhosis and terminal stage of liver disease. They have variable prevalence among patients with liver disease and have two major clinical and biochemical presentations. Autoimmune hepatitis (AIH) is the typical example of hepatocellular AILD, but it can also be presented under a cholestatic pattern. AIH has a scoring diagnostic system and respond in most cases to the treatment with prednisolone and azathioprine. Primary biliary cirrhosis (PBC) is the second most common AILD, with a cholestatic presentation and characterized by positive antimitochondrial antibody (AMA). It has an excellent response and long term outcome with the administration of ursodeoxycholic acid (UDCA). Another AILD that is thought to be a variant of PBC is the autoimmune cholangitis, being a disease that has biochemical and histological features similar to PBC; but the AMA is negative. Primary sclerosing cholangitis (PSC) is a rare entity of AILD that has a cholestatic presentation and respond poorly to the treatment, with the ultimate progression to advance liver cirrhosis in most patients. Other forms of AILD include the overlap syndromes (OS), which are diseases with mixed immunological and histological patterns of two AILD; the most commonly recognized one is AIH-PBC overlap (AIH-PSC overlap is less common). The treatment of OS involves the trial of UDCA and different immunosuppressants. Here we present three case reports of unusual forms of chronic liver diseases that most likely represent AILD. The first two patients had a cholestatic picture, whereas the third one had a hepatocellular picture at presentation. We discussed their biochemical, immunological and histological features as well as their response to treatment and their outcomes. Then, we compared them with other forms of AILD.     

Overlap syndromes with autoimmune hepatitis in chronic cholestatic liver diseases

Conditions exhibiting features of two different autoimmune liver diseases are commonly designated overlap syndromes, although there is no current agreement on what constitutes an overlap syndrome or specific diagnostic criteria. As in the classic autoimmune liver diseases, such as autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC), the etiology is unknown but presumed to be related to alterations of immune regulation. Distinction of these clinical entities is important for management as outcomes may differ from outcomes of patients with diagnosis of classic autoimmune liver diseases. Due to their presumed rarity, no large therapeutic trials are available and treatment of overlap conditions is empirical and based upon extrapolation of data from the primary autoimmune liver diseases. PBC–AIH overlap is the most frequently described overlap syndrome and may be associated with a poor prognosis. This may represent an important and unrecognized cause of resistance to ursodeoxycholic acid in patients with PBC. PSC–AIH overlap is less commonly reported. Prognosis may be better than in patients with PSC alone; however, worse than in patients with AIH alone. Further studies are needed for determining diagnosis, natural history and optimal therapeutic strategies of overlap syndromes of autoimmune liver disease.     

Connective tissue diseases and the liver

Connective tissue diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis, Sj?gren's syndrome, and scleroderma are systemic disorders that may have an autoimmune basis. The system manifestations vary, and there is frequent overlap among the syndromes. Liver involvement in patients with connective tissue diseases has been well documented but is generally considered rare. Although advanced liver disease with cirrhosis and liver failure is rare in patients with connective tissue diseases, clinical and biochemical evidence of associated liver abnormalities is common. Previous treatment with potentially hepatotoxic drugs or coincident viral hepatitis has usually been implicated as the main causes of liver disease in patients with connective tissue diseases. However, even after careful exclusion of these etiologies, the question remains whether to classify the patient as having a primary liver disease with associated autoimmune, clinical, and laboratory features or as having liver disease as a manifestation of generalized connective tissue disease. The main example of this pathogenetic dilemma is autoimmune hepatitis and SLE-associated hepatitis, which have been regarded as two different entities, although they have features in common of autoimmune syndromes. Several clinical and histopathologic features have been used to discriminate autoimmune hepatitis from SLE, a relevant diagnostic exercise because complications and therapy are quite different. Although hepatic steatosis and abnormal results on biochemical liver function tests are the most common hepatic abnormalities associated with connective tissue diseases, other less frequent abnormalities have been noted, such as nodular regenerative hyperplasia, portal vein obliteration and portal hypertension, features of primary biliary cirrhosis, and rarely portal fibrosis with abnormal lobular architecture. Vascular disorders of the liver also have been described, such as Budd-Chiari syndrome. Histologic assessment may reveal a variety of subclinical liver diseases. The aim of this contribution is to review the current published data regarding liver involvement in connective tissue diseases.     

Differenzialdiagnose Ikterus

Jaundice is the result of increased serum bilirubin levels. An initial differentiation of the underlying causes can be made by distinguishing increased conjugated and non-conjugated serum bilirubin and the findings of abdominal ultrasound examination. This combined approach enables a first classification into extrahepatic causes, hepatocellular dysfunction and intrahepatic and extrahepatic forms of cholestasis. In each diagnostic category of jaundice the differential diagnosis can be improved by additional imaging techniques comprising helical CT scanning, MRCP or ERCP, targeted laboratory tests and finally a liver biopsy. Specific difficult-to-diagnose cholestatic diseases include primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), autoimmune hepatitis PBC and PSC overlap syndromes, IgG4 cholangiopathy and familial deficiency of biliary transporters due to mutations in the ATP8B1, ABCB11, ABCB4 and Jag1 genes. Molecular genetic testing enables these familial conditions to be differentiated.     

Liver abnormalities in connective tissue diseases

The liver is a lymphoid organ involved in the immune response and in the maintenance of tolerance to self molecules, but it is also a target of autoimmune reactions, as observed in primary liver autoimmune diseases (AILD) such as autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis. Further, the liver is frequently involved in connective tissue diseases (CTD), most commonly in the form of liver function test biochemical changes with predominant cholestatic or hepatocellular patterns. CTD commonly affecting the liver include systemic lupus erythematosus, antiphospholypid syndrome, primary Sjögren's syndrome, systemic sclerosis, dermatomyositis, polimyositis, and anti-synthetase syndrome, while overlap syndromes between AILD and CTD may also be diagnosed. Although liver cirrhosis and failure are extremely rare in patients with CTD, unusual liver conditions such as nodular regenerative hyperplasia or Budd–Chiari syndrome have been reported with increasing frequency in patients with CTD. Acute or progressing liver involvement is generally related to viral hepatitis reactivation or to a concomitant AILD, so it appears to be fundamental to screen patients for HBV and HCV infection, in order to provide the ideal therapeutic regimen and avoid life-threatening reactivations. Finally, it is important to remember that the main cause of biochemical liver abnormalities in patients with CTD is a drug-induced alteration or coexisting viral hepatitis. The present article will provide a general overview of the liver involvement in CTD to allow rheumatologists to discriminate the most common clinical scenarios.     

Autoimmune liver diseases in systemic rheumatic diseases

Systemic rheumatic diseases (SRDs) are chronic, inflammatory, autoimmune disorders with the presence of autoantibodies that may affect any organ or system. Liver dysfunction in SRDs can be associated with prescribed drugs, viral hepatitis, alternative hepatic comorbidities and coexisting autoimmune liver diseases (AILDs), requiring an exclusion of secondary conditions before considering liver involvement. The patterns of overlap diseases depend predominantly on genetic determinants with common susceptible loci widely distributing in both disorders. In AILDs, it is important to identify the overlapping SRDs at an early stage since such a coexistence may influence the disease course and prognosis. Commonly co-occurring SRDs in AILDs are Sjögren syndrome (SS), rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) in autoimmune hepatitis (AIH), and SS, RA or systemic sclerosis in primary biliary cholangitis. Owing to different disease complications and therapies, it is imperative to differentiate between SLE liver involvement and SLE-AIH overlap disease. Therapeutic options can be personalized to control coexisting conditions of liver autoimmunity and rheumatic manifestations in AILD-SRD overlap diseases. The collaboration between hepatologists and rheumatologists can lead to significant advances in managing such a complex scenario. In this review, we provide a comprehensive overview on coexisting AILDs in different SRDs and the therapeutic approach in managing these overlap diseases.     

Primary and secondary autoimmunity in hepatology

Primary autoimmune liver diseases can be hepatitic or cholestatic in nature. Autoimmune hepatitis, more often diagnosed in women, is characterized by biochemical and histological activity, with polyclonal hypergammaglobulinemia as a frequent feature. Antinuclear and anti-smooth muscle antibodies are the serological hallmarks of type 1 autoimmune hepatitis, whereas liver-kidney microsomal antibody type 1 and liver cytosol antibody type 1 designate the type 2 form. Response to immunosuppression is usually excellent. The most frequent cholestatic autoimmune disease is primary biliary cirrhosis, characterized by anti-mitochondrial antibody positivity and typical bile duct lesions observed on liver biopsy. Treatment with biliary acids improves the biochemical picture, may alleviate pruritus, and delays the development of end-stage liver disease. Primary sclerosing cholangitis occurs more frequently in men and affects both the intra- and extrahepatic biliary trees, determining the typical "beading" appearance. Associated inflammatory bowel diseases are often observed. To date, no medical therapy is able to modify the course of this disease. Autoimmune cholangitis is an anti-mitochondrial antibody-negative cholestatic disease with most of the features of primary biliary cirrhosis. "Overlap" syndromes where autoimmune hepatitic and cholestatic features coexist in the same patient, have also been reported. Autoimmune phenomena secondary to hepatitis C virus-related liver disease such as the occurrence of antinuclear, anti-smooth muscle antibodies and liver-kidney microsomal antibody type 1 are often observed.     

Treatment of autoimmune and extrahepatic manifestations of hepatitis C virus infection

Hepatitis C virus (HCV) infects mononuclear cells and may be responsible, as are other viruses, for immunologic disorders. The immunologic abnormalities observed in HCV infections are usually non-specific (i.e. cryoglobulinemia, immune complex deposits, autoantibodies). The association with cryoglobulinemia is clear and cryoglobulinemia-related symptoms are usually improved by interferon alpha treatment, although patients often relapse after the end of treatment. The relationship with other immunologic abnormalities is less clear. The occurrence of antismooth muscle or anti-nuclear antibodies does not seem significantly different in hepatitis C infection than in other hepatic disorders, particularly hepatitis B. However, anti-liver kidney microsomal (LKM1) antibodies are present significantly more often than in patients with other liver diseases. When clinical, histologic and biological findings suggest HCV infection with chronic hepatitis, interferon alpha or combination therapy with ribavirin are treatment options When the clinical context and results of laboratory tests suggest an autoimmune disorder or overlap syndromes (i.e. both autoimmune and viral hepatitis), interferon should not be given as a first intention, since revelation or exacerbation of autoimmune hepatitis has been reported with interferon. A marked prevalence of anti-HCV antibodies has also been reported in patients with sialadenitis, lichen planus and thyroiditis. Interferon may induce or worsen these immunologic diseases, but there are very few studies showing improvement of these manifestations with interferon.     

Diagnostic and therapeutic questions in overlap syndromes of autoimmune hepatitis

The term 'overlap syndromes of liver diseases' includes coexistence of autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC), primary biliary cirrhosis (PBC). Due to their unknown etiology, as well as their variable presentation with mixed clinical and biochemical features, these overlap syndromes are often a diagnostic and therapeutic challenge for hepatologists. The most frequent association reported occurs between AIH and PBC. More rare is the overlap between AIH and PSC, typical in young age and often concomitant with an inflammatory bowel disease as ulcerative colitis. The treatment of choice is based on ursodeoxycholic acid and immunosoppressive drugs, used at the same time or consecutively, according to the course of disease. Histological examination seems an important tool, but often does not help for a correct diagnosis due to lack of specificity. Two particular forms of variant syndrome are the so called outlier syndromes, without clear characteristics of overlap: the autoimmune cholangitis, probably a form of PBC anti-mitochondrial antibodies negative, and the hepatitis C virus related with stigmata of autoimmunity, such as nonspecific autoantibodies at low titer. The diagnostic score system elaborated in 1999 by the International AIH Group can help for diagnosis, even if its definite validity is lacking.     

Transitions between variant forms of primary biliary cirrhosis during long-term follow-up

BackgroundConditions exhibiting features of two different autoimmune liver diseases are designated overlap syndromes. Variant forms display some, but not all, characteristics of a distinct autoimmune liver disease. We describe transitions over time between variant forms of PBC, i.e. AMA-negative PBC, autoimmune hepatitis (AIH)–PBC overlap and autoimmune cholangitis (AIC) in a large cohort of PBC patients in Sweden.MethodsWe retrieved all patients with variant forms of PBC in six university hospitals in Sweden, covering 60% of the Swedish population. The diagnosis of PBC and its variants was based on laboratory findings and compatible histological features. The revised autoimmune hepatitis scoring system proposed by the International Autoimmune Hepatitis Group was used to establish the diagnosis of AIH.ResultsIn a population of 800 patients with PBC, we identified 35 (5%) variant forms; 25 patients with AIH–PBC overlap, 8 with AIC and 2 with AMA-negative PBC at the time of our study. The initial diagnoses were PBC (3 patients), AIH (3), AIH–PBC overlap (16), AIC (8) and AMA-negative PBC with (1) or without (4) concomitant AIH. The median follow-up was 125 (41–360) months. Immunosuppression and ursodeoxycholic acid induced a complete or good regression of increased aminotransferases in about half of the patients who were given one or both of these treatments.ConclusionsVariant forms of PBC are seen in approximately 5% of PBC patients in Sweden. Transition between different forms may occur, emphasizing the value of repeat biopsies, but established overlapping AIH–PBC seems to be stable over time.     

Autoimmunity in hepatitis C and D virus infection

SUMMARY. A large number of viruses are capable of inducing acute or chronic hepatitis. The syndrome of chronic hepatitis encompasses not only viral but also autoimmune liver diseases. The hepatitis C virus, and recently also the hepatitis D virus have been found to be associated with an array of autoimmune syndromes, diseases and markers of autoimmunity. The relationship of hepatotropic virus infection and the immune system leading to virus-associated autoimmunity, and its distinction from genuine autoimmune disease represents a fascinating field of research. Clinically, the differentiation between autoimmune liver diseases, virus infection and virus-associated autoimmunity is difficult and epidemiological evaluations have not come up with universally applicable and valid classification criteria. However, both autoimmune liver diseases and viral hepatitis can readily be diagnosed and distinguished through precise and molecularly determined immunological testing systems. The overlap of both, virus-associated autoimmunity, is still at the centre of research activities aimed at establishing diagnostic and risk-assessment criteria. Studies of molecular autoantigens and autoepitopes have begun to define the differences of the B-cell response in autoimmune disease and virus-associated autoimmunity. This provides data that may contribute to the safe application of therapeutic strategies as different as immunosuppression and interferon-α (IFN-α). The present review focuses on the clinical, epidemilogical and molecular aspects of these disease entities.