Hepatitis C virus-related chronic liver disease with autoantibodies to liver-kidney microsomes (LKM). Clinical characterization from idiopathic LKM-positive disorders

Thyroid Peroxidase Antibodies in Non-Interferon Treated Hepatitis C Patients in Pakistan

Objective. Interferon therapy of HCV infected patients is associated with development of thyroid dysfunctions. Patients with pretreatment presence of antithyroid peroxidase (TPO-Ab) are at greater risk. This study, probably the first in Pakistan, was planned to determine TPO-Ab in sera of treatment-naive local HCV patients. Setting. Centre for Nuclear Medicine (CENUM), Mayo Hospital, Lahore. Patients and Methods. During July to December 2012, 190 patients (140 females, 50 males) newly diagnosed for HCV infection were selected for this study. Their age range was 15–55 years (mean: 35.3 ± 9.1 years). 262 age matched healthy subjects (211 females and 50 males) were recruited as control. Serum-free thyroxin (FT₄) and thyroid stimulating hormone (TSH) were detected by radioimmunoassay techniques. Serum TPO-Ab titer was determined by ELISA method using commercial kits. Results. Serum FT₄ and TSH levels in HCV patients and controls were within normal range. Between two groups there was no significant difference in mean value of FT₄ (16.0 ± 3.0 versus 16.2 ± 3.9; P = 0.619) but mean TSH value was significantly lower in HCV patients (1.5 ± 0.8 versus 1.8 ± 0.9; P = 0.003). Among HCV patients 51 (26.8%) were TPO-Ab positive and among control subjects 18 (6.9%) were TPO-Ab positive. The difference was statistically significant (P < 0.001). Further analysis showed that among HCV patients 39 (27.8%) females and 12 (24.0%) males were TPO-Ab positive, respectively, and difference was not statistically significant (P = 0.873). Moreover, TPO-Ab positive patients were older and had significantly higher serum TSH as compared to TPO-Ab negative HCV patients. Conclusion. Independent of patient's gender and increasing with advancing age, about one-fourth of local untreated HCV patients are TPO-Ab positive and are at greater risk of developing thyroid disorders during and after interferon treatment.

New insights to the immunopathology and autoimmune responses in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune liver disease with profound changes in different compartments of the immune system, including those involved in innate, and adaptive immunity. New data from epidemiological studies of PBC have reinforced the thesis that the cause for this relatively uncommon disease is likely to be a combination of both environmental factors and a susceptible genetic predisposition. Recent findings of abnormalities of the innate immune system in PBC suggest that they may serve as links between the environmental factors and the early events in PBC development. Viral and bacterial infections as well as xenobiotics are some of the potential environmental factors that have been implicated in this complex process. Identification of the etiological factors for PBC will point to new preventive or therapeutic treatments.

Autoantibodies in autoimmune liver disease

Autoantibodies indicate an immune reactive state, but in liver disease they lack pathogenicity and disease specificity. Antinuclear antibodies, smooth muscle antibodies, antibodies to liver/kidney microsome type 1, antimitochondrial antibodies, and perinuclear antineutrophil cytoplasmic antibodies constitute the standard serological repertoire that should be assessed in all liver diseases of undetermined cause. Antibodies to soluble liver antigen/liver pancreas, asialoglycoprotein receptor, actin, liver cytosol type 1, nuclear antigens specific to primary biliary cirrhosis, and pore complex antigens constitute an investigational repertoire that promises to have prognostic and diagnostic value. These autoantibodies may emerge as predictors of treatment response and outcome. Antibodies to histones, doubled-stranded DNA, chromatin, and lactoferrin constitute a supplemental repertoire, and they support the immune nature of the liver disease. Final diagnoses and treatment strategies do not depend solely on serological markers. Autoantibodies are floating variables, and their behavior does not correlate closely with disease activity. There are no minimum levels of significant seropositivity, especially in children. Over-interpretation is the major pitfall in the clinical application of the serological results. New autoantibodies will emerge as the search for target antigens and key pathogenic pathways continues.

Identification of a new autoantibody in patients with chronic hepatitis

To comprehensively study autoantibodies in patients with chronic hepatitis (CH), especially those with hepatitis C virus (HCV) infection, proteins extracted from HepG2 cells were separated by two-dimensional electrophoresis. Spots reacting with sera from 15 patients with CH-C were detected by Western blotting. Proteins extracted from the spots were subjected to mass spectroscopy for identification by mass fingerprinting. Antigenicity of the proteins identified was confirmed by Western blotting and enzyme-linked immunoabsorbent assay. The localization of the autoantigens so detected was investigated by immunohistochemistry. Among 20 protein spots detected, four were identified as actin, heat shock protein (HSP) 70, HSP60, and a novel protein (hepalaminin). Hepalaminin consists of two domains of laminin beta-2 and a specific domain. Autoantibodies against the specific domain were detected in 60.8% of patients with CH-C, 37.7% of those with CH-B, 42.3% of those with autoimmune CH, 28.6% of nonalcoholic steatohepatitis, 10.0% of asymptomatic HCV carriers, but in no healthy volunteers. Antihepalaminin positivity in CH-C and CH-B was related to histologic grading. Immunohistochemical staining demonstrated that hepalaminin is present in the cytoplasm of hepatocytes and cholangiocytes but not of fibroblasts or the vascular epithelium. Hepalaminin is a novel protein expressed in hepatocytes and cholangiocytes. Autoimmunity to this protein may exacerbate inflammation in chronic viral hepatitis.

Treatment of hepatitis D

Delta virus related chronic hepatitis is difficult to treat. The response to alpha-interferon (IFN), which still represents the only therapy for chronic hepatitis D, varies widely and occurs at different times from the beginning of treatment. The rate of response is proportional to the dose of IFN, with 9 million units (MU) three times a week being more effective than 3 MU thrice weekly. Sustained responses are unusual and are accompanied by the clearance of serum hepatitis B virus surface antigen (HBsAg), seroconversion to anti-HBs and improvement of liver histology. Although disease of a short-standing may respond better to therapy, clear predictors of response are still unidentified. Besides IFN, other therapeutic approaches such as immunosuppressive drugs, acyclovir, ribavirin and thymosin, have been unhelpful. Available evidence does not support the use of deoxynucleotide analogues. Famciclovir has no effect on disease activity and hepatitis D virus (HDV)-RNA levels. Twelve- or 24-month lamivudine treatment does not significantly affect biochemical, virological or histological parameters. Pegylated-IFN could represent a reasonable therapeutic option in the long-term treatment required for chronic hepatitis D. Antisense oligonucleotides and prenylation inhibitors hold promise as therapeutic agents of the future. Liver transplantation provides a valid option for end-stage HDV liver disease; the risk of re-infection is lower for HDV than for HBV under long-term administration of hyperimmune serum against HBsAg. Molecularly tailored drugs capable of interfering with crucial viral replicative processes of HDV appear to be the best prospect in the treatment of hepatitis D.

Autoimmunity and viruses

Although viruses are commonly cited as triggers for autoimmune disease, the actual mechanisms by which they initiate autoimmunity are unknown. Molecular mimicry is the most popular hypothesis, and it proposes that viral antigens that share homologies with host antigens generate an immune response that damages host tissue. The viral antigen may not be needed for perpetuation of the disease, and cross-reacting immune responses can involve humoral, cellular, or both types of reactivity. Linear and conformational epitopes may be involved, and foreign antigens do not need to share exact amino acid sequences with self-proteins to activate autoreactive T cells. Bystander effects can enhance the autoimmune process if previously sequestered or cryptic antigens are exposed to the immune system, and superantigens that are produced by the pathogen and are not MHC restricted can result in marked polyclonal activation of CD4 and CD8 T cells. Future studies must differentiate the targets of pathologic immunity and distinguish self-antigens from infectious nonself-antigens. Transgenic animal models of AIH are needed to assess the pathogenicity of the antigenic targets.

Prevalence and epidemiology of autoimmune hepatitis

The incidence and characteristics of AIH differ in various geographic regions. Based on limited epidemiologic studies, the incidence of type 1 AIH among Caucasoid populations of Europe and North America ranges from 0.1 to 1.9/100,000/year. The disease is considerably less frequent in Japan. The relative proportion of AIH among cases with chronic hepatitis is low in regions with a high prevalence of viral hepatitis. Type 2 AIH is more frequent in southern Europe than in northern Europe, the United States, and Japan. The occurrence of anti-SLA/LP is also higher in European than in Japanese patients with type 1 AIH. The frequency of HLA markers that affect susceptibility to AIH varies between ethnic groups. DRB1*0301 (DR3) and DRB1*0401 (DR4) are the major risk factors for type 1 AIH in white European and North American populations. DRB1*0405 (DR4) is the principal risk factor in Japanese and adult Argentine patients with type 1 AIH, and DRB1*0404 (DR4) is the main susceptibility allele in Mestizo Mexicans. Children may have different clinical manifestations than adults, and the diagnoses of type 2 AIH, autoimmune sclerosing cholangitis, and APS1 should be considered. Uniform application of diagnostic criteria formulated by the International Autoimmune Hepatitis Group should strengthen future epidemiologic studies and extend awareness of AIH to yet unstudied minority groups.

Differences in anti-LKM-1 autoantibody immunoreactivity to CYP2D6 antigenic sites between hepatitis C virus-negative and -positive patients

Anti-liver kidney microsome type 1 autoantibodies (anti-LKM-1) are known to be present in sera of autoimmune hepatitis type II and a subset of chronic hepatitis C patients. The autoantigen to anti-LKM-1 has been identified to be cytochrome P450 IID6 (CYP2D6) and the most frequently cited CYP2D6 antigenic sites of anti-LKM-1 in sera from autoimmune hepatitis type II patients spans the region aa 256-269. Other antigenic sites on CYP2D6 exist and have been identified in the two patient groups. However, most of these sites are concentrated on the carboxyl-terminal side of the protein, and the amino-terminal region has not been thoroughly investigated. Here, we have studied the antigenicity of the CYP2D6 amino region and compared reactivities between hepatitis C virus (HCV)-negative and -positive Japanese patient groups. A total of 34 anti-LKM-1-positive sera (eight with autoimmune hepatitis type II and 26 with chronic hepatitis C) were included. The immunoreactivity of patients' sera was examined against four conformational and one linear CYP2D6 peptide fragments. A defined antigenic site spanning aa 181-245 was found to react with 88% (7/8) of autoimmune hepatitis type II patients, as opposed to only 38% (10/26) of chronic hepatitis C patients. This was a significant difference (P< 0.043). Among these positively reacting samples, five of the seven autoimmune hepatitis type II sera and four of the ten chronic hepatitis C sera also reacted with a synthetic peptide spanning aa 256-269. Anti-LKM-1 thus may be able to recognize simultaneously at least two antigenic sites on the CYP2D6 protein, and reactivities against individual epitopes may differ according to HCV infectivity status.

Xenobiotic considerations for the development of autoimmune liver diseases: bad genes and bad luck

The etiologic origins of autoimmune disease remain an enigma. Although considerable information on the mechanisms of immunopathology has been acquired, in part from murine models, such mechanisms have yet to be substantiated in human autoimmune disease. This absence of validation is especially true for organ-specific diseases like those affecting the liver. In this review we focus on the putative role of xenobiotics as inducing agents for autoimmune liver pathology. In particular, we discuss the autoantibody immune response, the humoral hallmark of autoimmune disease, as well as cellular immune responses. We believe that exposure to environmental factors, namely xenobiotics, is the initiating straw that breaks the camel's back, leading to the loss of tolerance to self proteins in genetically susceptible hosts. The end result is a perpetuating process that is determined by the governing features of the genetics of the host and by exposure to the inciting environmental agent. Interestingly, the liver, an organ that plays a major role in immune tolerance, can itself become the target of autoreactivity and immune destruction.

Effect of interferon therapy on Japanese chronic hepatitis C virus patients with anti-liver/kidney microsome autoantibody type 1

AIM

The aim of this study was to determine the prevalence of anti-liver/kidney microsome autoantibody type 1 (anti-LKM-1) among hepatitis C virus (HCV)-infected Japanese patients at various stages (chronic hepatitis, liver cirrhosis and hepatocellular carcinoma), and to assess the influence of anti-LKM-1 on interferon therapy.

METHODS

A total of 390 serum samples from 215 HCV-infected patients with chronic hepatitis (HCV-CH), 81 HCV-infected patients with liver cirrhosis (HCV-LC), and 94 HCV-HCC infected patients were subjected to examination. Ninety-one HBsAg-positive patients and 137 healthy subjects served as controls. Anti-liver/kidney microsome autoantibody type 1 was determined by using a newly developed ELISA using recombinant cytochrome P450 IID6 as the antigen.

RESULTS

Anti-liver/kidney microsome autoantibody type 1 was detected in six of the 390 (1.5%) chronic HCV-infected patients (four were HCV-CH and two were HCV-LC); in contrast, it was not detected in control groups. Among the 110 HCV-CH patients treated with interferon (IFN), four were positive for anti-LKM-1. No change in anti-LKM-1 immunoreactivity from negative to positive during interferon therapy was observed. Moreover, no increase in the serum alanine aminotransferase level was observed in these four patients with anti-LKM-1.

CONCLUSION

Our study indicates that: (i) anti-LKM-1 does not aggravate the liver disease associated with HCV infection; and (ii) no change in anti-LKM-1 immunoreactivity from negative to positive or no aggravations of liver dysfunction were observed among HCV-CH patients during the IFN therapy for Japanese patients with liver disease.

Autoimmune hepatitis

Autoimmune hepatitis (AIH) is a rare disease, characterized by female predominance, hypergammaglobulinemia, autoantibodies, association with HLA DR3 and HLA DR4 and a good response to immunosuppression. Different subtypes of AIH may be distinguished, based on differences in the autoantibody patterns. AIH type 1 is characterized by anti-nuclear (ANA) and/or anti-smooth muscular (SMA) autoantibodies. AIH type 2 is characterized by liver/kidney microsomal autoantibodies (LKM). AIH type 3 may be distinguished by autoantibodies to soluble liver proteins (SLA) or the liver pancreas antigen (LP). AIH-2 affects predominantly pediatric patients and is characterized by a more severe clinical course, a higher frequency of relapse under immunosuppressive treatment and a more frequent progression to cirrhosis. In contrast, AIH types 1 and 3 show a higher age of onset and a better long-term response to immunosuppressive treatment. At present, the treatment of choice is prednisone alone or a combination with prednisone and azathioprine. Both treatment protocols show high survival rates. However, a rate of 13% of treatment failures and the failure to induce permanent remission in most patients underlines the urgent need to develop additional treatment regimens. A yet unknown genetic predisposition is believed to act as the underlying etiological factor in AIH. This genetic predisposition includes a few known risk factors such as the presence of HLA DR3 or HLA DR4, deletions of C4A alleles and female gender. Furthermore, it has to be postulated that defects in immunoregulatory genes exist. A model for such defects may be the autoimmune polyglandular syndrome type 1 (APS1), which results from the defects in a single gene, the autoimmune regulator type 1 (AIRE-1). Patients with APS1 suffer from mucocutaneous candidiasis and a number of organ-specific autoimmune diseases. Characteristic is a high variability in the number and character of the disease components in APS1, indicating that other genetic and environmental factors may strongly modulate the outcome of disease. Environmental factors may comprise chemical influences, such as nutritional compounds and drugs, or virus infections. Several drugs or chemicals were shown to induce hepatitis with autoimmune involvement, e.g. tienilic acid, dihydralazine and halothane. Adduct formation of an activated metabolite is believed to act as a trigger and to induce a specific immune response. Similarly, viruses were repeatedly shown to trigger autoimmune hepatitis. In virus infections, sequence similarities between viral and self-proteins may trigger autoimmune processes and the simultaneous presence of inflammatory cytokines during virus infection may further increase the risk of developing self-perpetuating autoimmune reactions which overshoot.

Pathologic features of chronic hepatitis. A review and update

The general histopathologic changes of chronic hepatitis and those related to the various causes are reviewed. Consideration also is given to underlying or associated diseases and to mixed infections in chronic viral hepatitis. Changes occurring in exacerbations or relapses are described. Selected histopathologic changes are illustrated. The nomenclature is reviewed briefly, with emphasis on separation of activity from stage of disease.

Sera of children with hepatitis C infection and anti-liver-kidney microsome-1 antibodies recognize different CYP2D6 epitopes than adults with LKM+/HCV+ sera

BACKGROUND

Liver-kidney microsome type 1 (LKM1) antibodies are specific markers of autoimmune hepatitis (AIH) type 2. Antibodies to LKM1 have been found in 2% to 3% of adults infected with hepatitis C virus (HCV) without AIH. Thirty percent of these antibodies are directed against linear sequences of CYP2D6 protein. LKM1 antibodies in HCV+/LKM1+ sera and in sera of AIH patients do not recognize the same CYP2D6 epitopes. The current study was conducted to determine whether LKM1 antibodies in HCV+/LKM1+ children's sera are the result of the same immune response as the antibodies described in AIH type 2 and in HCV+/LKM1+ adult patients.

METHODS

Sera from 10 HCV+/LKM1+ children were tested against human liver microsomal and cytosolic proteins by Western blot analysis and against synthetic peptides of the CYP2D6 sequence between amino acids 200 and 429 by dot blot. The same sera were tested against radiolabeled CYP2D6 by immunoprecipitation.

RESULTS

Four of 10 sera tested by Western blot analysis showed immunoglobulin (Ig) G-type antibodies against CYP2D6, and 2 had antibodies against proteins of 58, 66, and 84 kDa. One of the sera also contained IgM-type anti-66-kDa and 84-kDa proteins. The radioligand test detected anti-CYP2D6 antibodies in 9 of 10 patients. Five of the anti-CYP2D6-positive sera recognized a peptide between amino acids 200 and 429 including amino acids 254-271.

CONCLUSIONS

Most HCV+/LKM1+ sera from children recognize conformational epitopes of the CYP2D6 antigen, and half recognize linear epitopes. Some HCV+/LKM1+ sera demonstrated antibodies against the AIH type 2 main antigenic site of the CYP2D6. Screening of HCV RNA should be performed before starting treatment of presumed autoimmune hepatitis associated with LKM1.

Extrahepatic manifestations of chronic hepatitis C infection and the interrelationship between primary Sjögren's syndrome and hepatitis C in Swedish patients

OBJECTIVE

To analyse the frequency of some extrahepatic manifestations of chronic hepatitis C virus (HCV) infection in northern European patients, including a postulated association between HCV and primary Sjögren's syndrome (SS).

DESIGN

Cohort study.

SETTING

Department of Medicine, Malmö University Hospital, Sweden.

PATIENTS

Twenty-one patients with HCV infection and 53 with primary SS (according to the Copenhagen criteria).

MAIN OUTCOME MEASURES

Cryoglobulins were analysed in all patients, while patients with primary SS were investigated with regard to markers of HCV infection, and HCV patients with objective tests of SS (Schirmer-1 test, break-up time, van Bijsterveld score, sialometry, labial salivary gland biopsy) and antibodies against nuclear antigens, smooth muscle (SMA) and mitochondria (AMA). HCV antigens in small salivary glands from lower lip biopsies were detected by immunohistochemical analysis.

RESULTS

Only one of the SS patients had detectable cryoprecipitates, while another was HCV-positive. None of the 21 HCV patients had cryoprecipitates. A total of 14/21 (67%) patients with HCV infection had at least one abnormal objective test suggestive of xerostomia or keratoconjunctivitis sicca, while eight (38%) had objective evidence of both eye and salivary gland involvement. HCV antigens were not detected in affected glands. Only two patients had clinical symptoms of SS, and two fulfilled the Copenhagen criteria for SS. None of the HCV-positive patients had detectable antibodies against SS-A, SS-B, RNP, Jo-1, PCNA or Scl-70, and the frequency of ANA/SMA/AMA was low.

CONCLUSIONS

While involvement of salivary and lacrimal glands was common in Swedish patients with HCV infection, cryoglobulinaemia was not observed. The pathogenetic mechanism responsible for glandular inflammation appears to be different from that in primary SS. HCV infection does not seem to be an aetiological factor for primary SS in this population. These observations suggest that viral, genetic or possibly environmental factors may be responsible for the reported high frequencies of systemic complications associated with chronic hepatitis C infection in southern Europe.

Oral lichen planus in patients infected or noninfected with hepatitis C virus: the role of autoimmunity

Serum proteins, serum immunoglobulins, anti-nuclear antibodies (ANA), anti-smooth muscle antibodies (ASMA), anti-mitochondrial antibodies (AMA), anti-liver-kidney antibodies (LKM), anti-parietal-cell gastric antibodies (APCA), anti-epithelial antibodies and concomitant autoimmune disease were studied in 27 OLP-HCV+ve subjects and in a comparable group of 23 who were OLP-HCV-ve. In addition, all the patients with chronic liver disease who were sero-positive for ANA, AMA or LKM were scored using the new aggregate scoring system to detect those with the accepted criteria for the diagnosis of autoimmune hepatitis (AIH). Hypergammaglobulinemia was more frequent in OLP-HCV+ve than in OLP-HCV-ve (P = 0.008) subjects. Serum IgG and IgM levels were higher in HCV+ve than in HCV-ve (respectively, P = 0.017 and P = 0.018) individuals. However, there was no difference in the frequency of any autoantibody between OLP-HCV+ve and OLP-HCV-ve patients. Overall, immunologically-related abnormalities were found in 17(63%) OLP-HCV+ve and 11(48%) OLP-HCV-ve (P = 0.43) patients. Three OLP-HCV-ve and no OLP-HCV+ve patients had score criteria of probable AIH. The present and our previous data suggest that OLP patients with HCV infection neither had evidence of autoimmune liver damage nor had abnormal humoral immune-responses, with the exception of higher than control levels of serum immunoglobulins. Cryoglobulins may be responsible.

Interferon therapy in LKM-1 positive patients with chronic hepatitis C: follow-up by a quantitative radioligand assay for CYP2D6 antibody detection

BACKGROUND/AIMS

Liver/kidney microsomal type 1 (LKM-1) antibodies described by indirect immunofluorescence using frozen sections of kidney, stomach and rat liver define a group of patients with type 2 autoimmune hepatitis. Sera react with a non-glycosylated 50-kD protein of the endoplasmic reticulum, which was recently identified as cytochrome P4502D6 (CYP2D6). LKM-1 antibodies may also be associated with hepatitis C virus infection (HCV+/LKM-1+). For this subset of patients, the choice of steroids or interferon alpha therapy may be difficult because of the association of hepatitis C virus infection and autoimmune manifestations. Recently we developed a quantitative immunoprecipitation radioligand assay using 35S-methionine-labeled CYP2D6 protein produced by in vitro transcription and translation reaction. This method detects antibodies against linear and conformational epitopes in both AIH-2 and HCV+/LKM-1+ patients. The aim of this study was to analyze the time-course of HCV+/LKM-1+ patients, applying our radioligand assay over a long follow-up.

METHODS

We studied five patients who were positive for CYP2D6 antibodies from among 235 chronic hepatitis C virus hepatitis patients (2.1%) treated with interferon alpha for a minimal follow-up of 2 years. We analyzed LKM-1 antibody titer sequentially by radioligand assay, HCV RNA titer and alanine aminotransferase activity in these patients.

RESULTS

We found no aggravation of liver disease in this group of patients. Three of these patients showed a sustained biochemical and virological response after interferon. Two others responded partially to interferon therapy. Alanine aminotransferase levels and HCV-RNA decreased during interferon therapy in responder patients. CYP2D6 antibodies did not change in three responder patients during follow-up. One responder patient decreased CYP2D6 antibody level by radioligand assay, but indirect immunofluorescence titers showed a similar pattern. One partial responder patient decreased CYP2D6 antibody level but was negative by indirect immunofluorescence.

CONCLUSIONS

Our results show that patients with hepatitis C virus who are positive for CYP2D6 antibodies may be treated with interferon, and respond in the same way as CYP2D6 antibody negative patients. Radioligand assay could be helpful for monitoring HCV+/LKM-1+ patients receiving interferon therapy.

Chronic hepatitis C associated with anti-liver/kidney microsome-1 antibody is not a subgroup of autoimmune hepatitis

To determine whether "autoimmune hepatitis type IIb" should be categorized as a subgroup of autoimmune hepatitis, we conducted a clinicopathological study of 25 adult Japanese patients who were positive for anti-liver/kidney microsome-1 (anti-LKM-1) anti-body and infected with the hepatitis C virus (HCV). Anti-LKM-1 was determined by indirect immunofluorescence and by the double immunodiffusion assays we have developed. Twenty-two patients did not present any unusual symptoms or any associated diseases during the course of their chronic HCV infection. The spectrum of HCV genotypes of these patients did not significantly differ from that of anti-LKM-1-negative Japanese patients with chronic hepatitis C. Histological examination of liver biopsy specimens showed the usual characteristics of chronic hepatitis C and lack of characteristics of autoimmune hepatitis type I. No disease-specific HLA haplotypes were noted, and HLA-DR4, which is detectable in 88.7% of Japanese patients with autoimmune hepatitis type I, was detected in only 50.0% of our group, the same rate as the background frequency. Prednisolone was effective in none of the six patients treated, but interferon was effective in six of ten treated patients (60%). From these results, we conclude that "autoimmune hepatitis type IIb" should not be categorized as autoimmune hepatitis, and that this subgroup is essentially chronic hepatitis C in which an autoantibody has been produced during the course of chronic HCV infection.

Autoimmune hepatitis type 2 and hepatitis C virus infection: study of HLA antigens

BACKGROUND/AIMS

Markers for hepatitis C virus are often detectable in patients suffering chronic hepatitis with liver-kidney microsomal type 1 antibodies. Several authors have suggested that two subsets of those patients can be defined: a) hepatitis C virus negative and b) hepatitis C virus positive. The aim of this work was to further analyze the possible genetic association, HLA class I and II, in these two groups of patients.

METHODS

HLA was analyzed in 49 patients. Class I was studied using a standard lymphocytotoxicity test and in class II a reverse hybridization-based test for DRB1 typing and PCR-SSO for DQB1 typing were used. Sixty healthy Spanish subjects and 39 chronic hepatitis C subjects without anti-LKM1 antibodies were used as control groups for the "a" and "b" subsets, respectively.

RESULTS

No significant association was found with class I specificities in either group. DQB1 typing showed a very significant increase of DQ2 in the "a" group (93.3% vs. 48%; RR = 15; Pc = 0.0025), and DRB1 typing from the "b" group revealed a high association with DR7 (82.3% vs. 43.6%; RR = 6; Pc = 0.0086).

CONCLUSIONS

Our studies revealed a strong association with DQ2 for the "a" group and for the first time an extremely high association with DR7 antigen for the "b" subset. Hence it is possible to establish a different genetic profile in these two patient groups.

Frequency and significance of antibodies to P450IID6 protein in Japanese patients with chronic hepatitis C

BACKGROUND/AIMS

The aims of the current study were to assess the frequency and the significance of antibodies to cytochrome P450IID6 protein (anti-P450IID6) in various diseases among Japanese patients.

METHODS

Sera from 541 patients were tested by indirect immunofluorescence, and the specificity of anti-P450IID6 was ascertained by either enzyme immunoassay (ELISA) or Western blot using recombinant antigen or rat liver microsomes.

RESULTS

Anti-P450IID6 was found in only 6 of 235 patients (2.6%) with chronic active hepatitis (CAH) positive for hepatitis C virus (HCV) antibody and quantitative HCV-RNA with genotypes II and IV. The predominant epitopes on immunoblots were 66 and 50KD, a 10KD band being the newly underfined microsomal antigen. Even in the patients negative for autoantibodies to nuclear antigens (ANA) by routine indirect immunofluorescence test, various ANA were detected by the newly developed recombinant ELISA. These patients were younger, with lower gamma-globulin and IgG levels than patients with autoimmune hepatitis. Three of five patients with anti-P450IID6 responded well to interferon therapy and one received prednisone when interferon was ineffective. Interestingly, only this patient was diagnosed as definite autoimmune hepatitis according to the criteria proposed by the International Autoimmune Hepatitis Group (IAHG). The other five patients who did not satisfy the IAHG criteria might be considered as CAH-C with autoimmune features. No autoimmune hepatitis patients positive for anti-P450IID6 were identified in the current study, indicating that the variant is very rare in Japan.

CONCLUSIONS

Anti-P450IID6 in CAH-C patients in Japan is not as rare as expected. Anti-P450IID6 among Japanese patients has uncertain significance and precludes further characterization of CAH-C with autoimmune features, which might require interferon therapy.

Absence of LKM-1 antibody reactivity in autoimmune and hepatitis-C-related chronic liver disease in Sweden. Swedish Internal Medicine Liver club

BACKGROUND

Type-2 autoimmune hepatitis is a subgroup of chronic hepatitis characterized by the presence of liver/kidney microsomal autoantibodies type 1 (LKM-1). A frequent association with chronic hepatitis C suggests that hepatitis virus might trigger autoimmune reactivity. LKM-1-positive chronic hepatitis is not uncommon in southern Europe but is rarely seen in the USA and the UK. The prevalence in Scandinavia is hitherto unknown.

METHODS

We used an automated prototype LKM-1 immunometry-based assay (IMx) to detect LKM-1 antibodies in sera from 350 Swedish patients with chronic liver diseases (100 with primary biliary cirrhosis, 80 with primary sclerosing cholangitis, 100 with hepatitis C, and 70 patients with various forms of chronic hepatitis, including 36 autoimmune cases), and from 17 children with autoimmune hepatitis. Sera reactive in the IMx assay were subjected to immunofluorescence testing.

RESULTS

No clearly LKM-reactive sera were detected. Serum samples from 29 patients were borderline reactive in the IMx assay but tested negative in the confirmatory immunofluorescence test. Positive tests in the former assay were likely caused by reactivity against microsomal antigens other than LKM-1/cytochrome P450IID6.

CONCLUSIONS

LKM-1-positive type-2 autoimmune hepatitis is very rare in Sweden. Furthermore, chronic hepatitis C did not trigger this type of autoimmune reactivity in our patients, probably owing to genetic insusceptibility.

Autoimmunity in hepatitis C and D virus infection

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-alpha (IFN-alpha). The present review focuses on the clinical, epidemiological and molecular aspects of these disease entities.

[Autoimmune hepatitis and hepatitis C]

From autoimmune hepatitis (AIH) classification which recognizes three types of AIH, we discuss the main relations between hepatitis C virus (HCV) infection and AIH. Type I AIH is associated with antinuclear and antismooth muscle antibodies, and with other autoimmune diseases. There is no relation between type I AIH and HCV. Type I anti-liver kidney microsome and anti-liver cytosol I antibodies represent the hallmark of type II AIH. Among type II AIH, two subgroups emerged: type IIa AIH (10-40%) are true AIH (sensitive to steroids but worsens with interferon alpha), whereas type IIb AIH (60-90%) appear as a particular form of HCV hepatitis. Type IIb AIH have a moderate activity, a low titer of autoantibodies, anti-GOR antibodies but never anti-liver cytosol I, no sensitivity to steroids but are sensitive to interferon alpha. The hallmark of type III AIH are anti-cytosol antibodies, but these AIH have the same characteristics as type I AIH. The classification between true AIH (I, IIa, III) or "pseudo-AIH" due to HCV infection has major therapeutic implications. Steroids or immunosuppressive treatments are effective in type I, IIa and III AIH but have no efficacy in type IIb AIH. Alpha interferon has an efficacy in type IIb AIH, but it has no efficacy and may even worsen hepatitis in type I, IIa and III AIH.

Efficacy and safety of interferon alfa therapy in chronic hepatitis C with autoantibodies to liver-kidney microsomes

Interferon alfa (IFN) therapy is efficacious in chronic viral hepatitides. It may, however, cause adverse immunologic reactions in patients with concomitant autoimmune phenomena. A minority of patients with chronic type C hepatitis have antibodies against liver and kidney microsomes (anti-LKM) in serum. We therefore carried out this study to find out whether IFN is safe and efficacious also in this subgroup. We treated 92 consecutive cases of chronic hepatitis C with IFN. Twelve patients had anti-LKM< and the remaining 80 tested negative to the anti-LKM. The hepatitis C virus (HCV) infection was diagnosed on the basis of positive anti-HCV and HCV-RNA tests. We compared the clinical and virological virological results of the therapy and the side effects found in the two groups. We found that the response to therapy and the outcome after 1 year of follow-up were similar. Treatment was discontinued in one anti-LKM-positive patient because of a drastic increase in ALT levels at the fourth month of therapy. No untoward effect was observed in the other cases. Hepatitis C patients with anti-LKM may be exposed to an increased risk of an adverse hepatitic reaction while being treated with IFN. However, we found that the extent of the risk was minimal compared with the expected benefits of the therapy. IFN is therefore recommended as the first therapy to choose in these patients. They must, however, be monitored more closely for possible liver dysfunction than the ordinary hepatitis C patient.

Autoimmune hepatitis versus viral hepatitis C

Numerous viruses are capable of inducing the syndrome of chronic hepatitis. Among them are the hepatitis B, C and D viruses. Out of the most common agents of chronic hepatitis, the hepatitis C virus has been found to be strikingly associated with autoimmune diseases and serological markers of autoimmunity. Conversely, the syndrome of genuine autoimmune hepatitis lacks evidence of previous or ongoing virus infection and is diagnosed by additionally excluding metabolic, toxic, and genetic causes of chronic hepatitis, and by the response to immunosuppressive treatment. This review article summarizes the current knowledge of hepatotropic virus-induced autoimmunity. It focuses on the present molecular and immunological definitions, the clinical and molecular distinction between autoimmune hepatitis and chronic viral hepatitis and the implications for the safe and efficacious therapy of these disease entities.

Prevalence of thyroid autoantibodies is not increased in blood donors with hepatitis C virus infection

Serum autoimmune reactions are found in many patients with hepatitis C. A high prevalence of thyroid dysfunction and antithyroid antibodies in patients with chronic hepatitis C was recently reported. We have compared the prevalence of thyroid dysfunction and antithyroid peroxidase antibodies in blood donors with hepatitis C virus (HCV) infection (study group) and in seronegative anti-HCV donors (control group). One hundred and ninety-two blood donors were studied: 96 were anti-HCV positive by ELISA 2 (48 males and 48 females; age 48 +/- 12.9 years, mean +/- SD), and 96 were HCV seronegative (55 males and 41 females; age 37 +/- 14.8 years). In all patients, serum TSH (0.25-4.2 mU/l) and fT4 (9-23 pmol/l) were measured by immunochemiluminiscent assays and antithyroid peroxidase antibodies (normal < 100 U/ml) by RIA. In all anti-HCV positive donors, hepatitis C viremia was tested using the nested polymerase chain reaction. Thyroid dysfunction was found in three females (3.1%) in the anti-HCV positive group (three cases of hypothyroidism), and in four (4.1%) anti-HCV negative blood donors (three cases of hypothyroidism, two females and one male; one case of hyperthyroidism, a female), (p = NS). Antithyroid peroxidase antibody titers were above normal values in 5 (5.2%) anti-HCV positive individuals and in eight (8.3%) anti-HCV negative blood donors (p = NS). These results do not show an increase prevalence of thyroid dysfunction and antithyroid peroxidase antibodies in blood donors with HCV infection when compared with a control group.

Detection of HCV-RNA in paraffin-embedded liver biopsies from patients with autoimmune hepatitis

BACKGROUND/AIMS

There may be a relationship between autoimmune hepatitis and viral infection. To examine this relationship, 19 patients with autoimmune hepatitis and/or chronic hepatitis C were studied.

METHODS

Patients were selected initially on the basis of having autoantibodies (anti-nuclear, anti-smooth muscle, or anti-liver-kidney microsomal) in serum. Formalin-fixed, paraffin-embedded liver biopsies from these patients were tested for HCV-RNA by polymerase chain reaction. The biopsies were examined histologically to detect features suggestive of chronic hepatitis C or autoimmune hepatitis. The results were correlated with serum anti-HCV and HCV-RNA, and with response to steroid therapy.

RESULTS

Five of the nineteen patients had detectable HCV-RNA in their liver biopsies. In two of three patients from whom serum was available, HCV-RNA was detectable. The remaining 14 patients were negative for HCV-RNA by tissue polymerase chain reaction. Serum was available from 11 of these patients, and serum HCV-RNA was negative in all. All of the three HCV-RNA-positive patients who were treated with steroids showed a partial response; tissue positivity for HCV-RNA was significantly higher in partial responders than in complete responders (60% vs 0%, p = 0.01). Severe portal and periportal inflammation with prominent plasma cells together with bridging parenchymal necrosis were seen more often in HCV-negative biopsies. Mild portal and periportal inflammation with portal lymphoid aggregates, apoptosis and spotty parenchymal necrosis were seen more in HCV-positive biopsies.

CONCLUSIONS

These results show that hepatitis C virus can be detected in some patients with circulating autoantibodies. The ability to detect HCV-RNA in paraffin-embedded archival material provides a valuable addition to the battery of available HCV tests.

Unbiased usage of T-cell receptor beta variable region genes in peripheral blood cells of hepatitis C patients: no correlation with superantigen effect

Hepatitis C virus (HCV) infection frequently causes chronic hepatitis and lack of virus clearance in these patients. In addition, many patients infected by HCV also present with hypergammaglobulinemia in the early stage of chronic infection. These observations raise a possible viral superantigen effect induced by HCV, because viral superantigen found in human immunodeficiency virus (HIV) or in replication of defective murine leukemia virus (MuLV) is associated with T-cell dysfunction and polyclonal activation of B cells. The possibility was investigated of whether HCV encodes any superantigen by analyzing the usage of T-cell receptor (TCR) from the peripheral blood lymphocytes (PBL) of patients with chronic hepatitis C. Two groups, one with hypergammaglobulinemia and the other without hypergammaglobulinemia, were studied for the usage of TCR beta chain by reverse transcription-polymerase chain reaction (RT-PCR) analysis. It was found that all genes of V beta variable chain were used in the PBL of these patients. Furthermore, there was no significant difference of the TCR expression pattern between these two groups, nor a complete deletion of a particular T-cell subset in either group. These results do not provide evidence for HCV superantigen, but indicate that the TCR usage in the patients was neither defective nor biased.

In vitro secretion of anti-GOR protein and anti-hepatitis C virus antibodies in patients with chronic hepatitis C

BACKGROUND/AIMS

Anti-GOR antibodies may reflect hepatitis C virus (HCV)--related autoimmunity or cross-reactivity with HCV core antigen. This study aimed to evaluate the clinical significance of anti-GOR antibodies.

METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated from 35 patients with HCV and 48 controls and cultured for 8 days. The in vitro antibody secretion by PBMC was determined using specific enzyme-linked immunosorbent assays and recombinant immunoblot assay.

RESULTS

In 22 of 35 patients with HCV (62.9%), PBMCs secreted anti-c22-3 or anti-c33c antibodies. However, in 3 of 48 controls (6.2%), PBMCs secreted anti-c33c antibodies alone. A significant in vitro anti-GOR response was found in 13 of 35 patients (37.1%) with HCV in relation to 4 of 48 controls (8.3%). In 12 of these patients (92.3%), anti-GOR were found in vitro and in serum. Two patients with HCV produced in vitro anti-GOR but not anti-c22-3 antibodies. Regarding disease activity, in vitro anti-GOR-positive patients with HCV had significantly higher alanine aminotransferase levels (108.8 +/- 17.8 U/L vs. 64.5 +/- 7.6 U/L; P < 0.01) and more frequent signs of chronic active hepatitis (10 of 13 [76.9%] vs. 10 of 22 [45.5%]) than patients with HCV without in vitro anti-GOR response.

CONCLUSIONS

The humoral anti-GOR response in vitro is closely related to HCV infection and disease activity. Anti-GOR and anti-HCV core antibodies are regulated independently. It is likely that anti-GOR may reflect an HCV-associated autoimmune phenomenon.

Interferon therapy in liver/kidney microsomal antibody type 1-positive patients with chronic hepatitis C

The association between liver/kidney microsomal antibody type 1 and adult cases of hepatitis C virus-related chronic liver disease has been firmly established. In the presence of both markers, evidence of autoimmunity (liver/kidney microsomal antibody type 1) and actual viremia (serum HCV RNA), the therapeutic dilemma arises between steroids, which are beneficial to autoimmune but deleterious to viral diseases, and interferon-alpha, which may exacerbate an autoimmune disorder. Six patients with liver/kidney microsomal antibody type 1 and serum HCV RNA were given interferon-alpha: three showed a response pattern similar to that observed in autoantibody-negative chronic hepatitis C cases; the other three developed a sharp transaminase peak, which was not followed by HCV RNA clearance. Considering the brisk flare-up of liver cell necrosis, interferon-alpha treatment proved to be dangerous in the above three liver/kidney microsomal antibody type 1/HCV RNA positive cases. Subsequent steroid administration reduced alanine aminotransferase peaks, but may be harmful in viral infections. Therapeutic alternatives are needed: they will probably include pure antivirals (exerting no immunostimulatory effects) with or without immunosuppressive drugs.

Interferon in HDV infection

Chronic hepatitis D is a usually severe and progressive liver disease due to infection with the hepatitis delta virus, a unique RNA virus requiring the hepatitis B virus helper function to exert its pathogenic potential. Alpha IFN is at present the treatment of choice for chronic viral hepatitis, but the results obtained in chronic hepatitis D are far from being satisfactory. Available data show that IFN is more likely to be effective if administered to patients with a recent infection (lasting less than 1 year) at high doses (9-10 MU thrice in a week) and for a prolonged length of time (at least 12 months). The optimal timing of IFN treatment remains to be addressed: apart from the clearance of HBsAg and seroconversion to anti-HBs (an event often occurring months to years after completion of a successful IFN treatment) no other early biochemical or virological events can predict a sustained response. Better therapeutic options are therefore needed. Unfortunately, antiviral agents, such as Ribavirin, active against HDV in cell cultures, have failed to confirm their attitude in the clinical setting. In vitro and in vivo evidence points to HBV as a possible target for antiviral therapy in chronic hepatitis D, providing the rationale for trying new deoxynucleotide analogues also in this severe form of hepatitis.

Differences in immune recognition of cytochrome P4502D6 by liver kidney microsomal (LKM) antibody in autoimmune hepatitis and chronic hepatitis C virus infection

LKM-1 antibody, which characterizes a subtype of autoimmune hepatitis (AIH), is also found in some patients with chronic hepatitis C virus (HCV) infection. It has been suggested that HCV initiates autoimmunity through molecular mimicry, because there is partial identity between HCV and cytochrome P4502D6 (CYP2D6), the putative target of LKM-1. Whether CYP2D6 is the target of LKM-1 in HCV-related liver disease, however, is controversial. To clarify this issue, we have studied by phage plaque assay and Western blot the reactivity to recombinant CYP2D6, isolated from a human liver cDNA library, in 55 patients with LKM-1, 18 (14 females, median age 12 years) anti-HCV-negative, with classical AIH, and 37 (27 females, median age 52 years) anti-HCV-positive. Reactivity to CYP2D6 was found in 72% of the anti-HCV-negative, but only in 27% of the anti-HCV-positive patients (P < 0.001), although immunofluorescence LKM-1 titres were similar in the two groups. In addition, to investigate whether the antibody responsible for the LKM-1 fluorescent pattern also reacts with CYP2D6, we have determined the specificity of LKM-1 antibodies present in the supernatant of lymphoblastoid B cell lines obtained from two patients with LKM-1-positive AIH. An oligo/monoclonal antibody thus generated gave both the typical fluorescent pattern and reacted with CYP2D6. Our results show that whilst antibodies producing the characteristic LKM-1 fluorescent pattern can react with CYP2D6, not all LKM-1-positive sera do so, particularly if obtained from patients with chronic HCV infection. This suggests that LKM-1 in HCV infection recognizes epitopes or antigens different from those targeted in AIH.

Hepatitis C virus in autoimmune liver disease in the UK: aetiological agent or artefact?

Hepatitis C virus antibody titres (anti-HCV) were measured in serum from 122 patients with autoimmune liver disease (96 with primary biliary cirrhosis and 26 with autoimmune chronic active hepatitis using three generations of enzyme immunoassay (EIA): first generation--Ortho, EIA1; second generation--Abbott, EIA2; and third generation--Murex, EIA3. Anti-HCV was below the positive cut-off level in all 26 autoimmune chronic active hepatitis patients for all tests, while seropositivity values in primary biliary cirrhosis were 31% (EIA1), 14% (EIA2), and 0% (EIA3). In primary biliary cirrhosis, anti-HCV values as measured by all three tests correlated positively with serum IgG concentrations, serum storage time, and a number of other indices of hepatic dysfunction. Multiple regression analysis showed that anti-HCV values were independently affected by both serum IgG and the length of storage time, although the magnitude of the effects varied between tests. When all three multiple regression models were applied to an extreme clinical example, however, EIA3 was least likely to give a false-positive result. The difference in test performance was emphasised further by examination of anti-HCV values in nine primary biliary cirrhosis patients (confirmed negative by recombinant immunoblot assay 2) in whom serial samples were tested (seven to 14 per patient, stored for one to 138 months). Apparent anti-HCV values (EIA1 and EIA2) increased with increasing serum storage time, but were unchanged when measured by EIA3. A similar pattern was evident in a limited study of five autoimmune chronic active hepatitis patients. As the second generation EIA is in widespread use and confirmatory testing is not always available, the effect of serum storage in addition to hyperglobulinaemia should be considered in the interpretation of positive results in auto immune and in other types of chronic liver disease.

Virus-induced autoimmunity in hepatitis C virus infections: a rare event

Serial serum samples from 16 Italian patients presenting with acute hepatitis C virus (HCV) infections (which progressed to chronic hepatitis in six) were screened for the non-organ-specific autoantibodies most frequently associated with autoimmune hepatitis (AIH), as well as for antibodies against the hepatic asialoglycoprotein receptor (ASGP-R) and against the GOR peptide. One patient had low titres (1:10-1:80) of liver-kidney microsomal (LKM-1) antibodies during the recovery phase and three others had transient low titres of anti-smooth muscle (IgM class, 1:10) or anti-ASGP-R (1:150-1:300). Anti-GOR was detected in 43 (65%) of 66 sera from 13 of these patients. There was no correlation between any of these findings and progression to chronicity. By comparison, 18 patients with AIH studied concurrently before institution of immunosuppressive therapy all had antinuclear and/or smooth muscle antibodies, or LKM-1, at 1:40-1:640 and anti-ASGP-R at 1:300-1:2,100. None of these 18 had evidence of HCV infection and all were seronegative for anti-GOR. The findings indicate that the autoantibodies usually associated with AIH are rare in HCV infections but the virus can very occasionally induce a transient autoimmune response. Anti-GOR appears to be an antibody specifically related to HCV infection and is probably not a marker of induced autoimmunity, and it does not predict progression to chronic hepatitis.

Sensitivity, specificity, and predictability of biopsy interpretations in chronic hepatitis

BACKGROUND

To determine the frequency of individual histological findings in different types of chronic hepatitis and to assess the sensitivity, specificity, and predictability of histological patterns in distinguishing these types, liver biopsy specimens were examined from 86 patients with autoimmune hepatitis (43 patients), chronic hepatitis B (11 patients), chronic hepatitis C (21 patients), and cryptogenic hepatitis (11 patients).

METHODS

Specimens were examined under code by a single hepatopathologist, and predefined histological features were sought. A histological diagnosis was rendered based on composite changes.

RESULTS

Patients with chronic hepatitis C had a higher frequency of portal lymphoid aggregates (76% vs. 42%, P = 0.02) and steatosis (52% vs. 16%, P = 0.006) than patients with autoimmune hepatitis, whereas the latter patients more commonly had severe periportal hepatitis (23% vs. 0%, P = 0.02), moderate to severe plasma cell infiltration of the portal tracts (66% vs. 21%, P = 0.005), and lobular hepatitis (47% vs. 16%, P = 0.04). Patients with chronic hepatitis B had a higher frequency of ground-glass hepatocytes (36% vs. 0%, P = 0.001) and multinucleated giant cells (54% vs. 2%, P = 0.0001) than those with autoimmune hepatitis and chronic hepatitis C. The histological diagnoses for these clinical entities had high specificity (81%-99%) and predictability (62%-91%) but low sensitivity (36%-57%).

CONCLUSIONS

Autoimmune hepatitis, chronic hepatitis B, and chronic hepatitis C have characteristic individual histological features. Histological patterns based on these features have high specificity and predictability but low sensitivity.

Antibodies to soluble liver antigen, P450IID6, and mitochondrial complexes in chronic hepatitis

BACKGROUND

Antibodies to soluble liver antigen, P450IID6, and the E2 subunits of mitochondrial dehydrogenase complexes occur in autoimmune liver diseases, but their specificities and implications are uncertain. The aims of the present study were to assess the importance of these autoantibodies in different types of chronic hepatitis.

METHODS

Sera from 62 patients with autoimmune hepatitis, 37 patients with cryptogenic hepatitis, and 19 patients with chronic hepatitis C were assessed under code by enzyme immunoassay.

RESULTS

Antibodies to soluble liver antigen were found in 7 patients with autoimmune hepatitis (11%) and 5 patients with cryptogenic disease (14%). Patients with antibodies to soluble liver antigen were indistinguishable from seronegative counterparts with autoimmune hepatitis. Seropositive patients with cryptogenic hepatitis had autoimmune features, and they responded to corticosteroid therapy. Five patients (8%) with autoimmune hepatitis were seropositive for antibodies to mitochondrial complexes. Three lacked antimitochondrial antibodies. None of the patients had antibodies to P450IID6, and patients with chronic hepatitis C were seronegative for all markers.

CONCLUSIONS

Antibodies to soluble liver antigen do not define a distinct subgroup of patients with autoimmune hepatitis. They may be found in some patients with corticosteroid-responsive cryptogenic hepatitis. Antibodies to E2 subunits and P450IID6 are uncommon in adults with chronic hepatitis.

Evidence against hepatitis viruses as important causes of severe autoimmune hepatitis in the United States

To determine if the hepatitis viruses are important etiologic factors in autoimmune hepatitis, the clinical, immunoserologic, virologic and HLA phenotypes of 105 of the latter patients were assessed prospectively and compared to 45 patients with chronic viral hepatitis. Patients with autoimmune hepatitis were more often women with higher serum aspartate aminotransferase and immunoglobulin levels than patients with viral disease. Only eight patients (8%) were seropositive for anti-HBc and anti-HBs (four patients) or anti-HCV (four patients) and none with anti-HCV were reactive by second generation immunoassay or recombinant immunoblot assay. Smooth muscle (90 vs. 22%, P < 0.001) and antinuclear (70 vs. 22%, P < 0.001) antibodies were more common in patients with autoimmune hepatitis and the titers more frequently exceeded 1:80 (84 vs. 11%, P < 0.0001). Patients with autoimmune hepatitis were more often positive for HLA B8 (48 vs. 20%, P < 0.01) and DR3 (49 vs. 20%, P < 0.003) and they more frequently had the HLA A1-B8-DR3 phenotype (38 vs. 10%, P < 0.003). Only one of the 120 patients tested for anti-LKM1 was seropositive. We conclude that in an American referral population autoimmune hepatitis usually lacks virologic markers and has a distinctive clinical, immunoserologic and HLA phenotype. Hepatitis viruses are not important immunogenic stimuli for non-organ specific antibodies and they are unlikely to be important causes of this form of autoimmune hepatitis.

Characterization and clinical relevance of liver-pancreas antibodies in autoimmune hepatitis

The isolation of a marker antigen from rat liver and pancreas tissue, which reacts with antibodies in a subtype of autoimmune hepatitis by complement fixation test, enzyme-linked immunosorbent assay and Western blot, is described. The liver-pancreas antigen could be detected in tissue from different human or animal organs, but liver and pancreas yielded the highest activity. A highly specific antigen fraction was obtained by gel filtration and ion exchange chromatography with a 100,000 g supernatant from rat liver tissue, and this preparation was shown to be devoid of nuclear, mitochondrial and microsomal antigens and cytokeratin 8 and 18, as demonstrated by appropriate marker antibodies. These data and absorption studies with cell organelles indicate that liver-pancreas antigen is a cytosolic protein. By Western blotting, two major epitopes at molecular weights 52 kD and 48 kD could be visualized. Sera from 175 patients previously shown to have high complement-fixing activity to a nonpurified liver-pancreas antigen fraction were further analyzed. All were positive by enzyme-linked immunosorbent assay with the purified liver-pancreas antigen fractions, and 111 were also positive by Western blot. Eighty-six sera reacted with the 52-kD determinant, 33 with the 48-kD determinant and 2 with both determinants. In 117 of the 175 patients, antibody to liver-pancreas antigen was associated with other autoantibodies known to characterize subgroups of autoimmune hepatitis. Thus 19 patients had antibodies to nuclei and 96 to actin but none to liver-kidney microsomes, hereby suggesting that antibody to liver-pancreas antigen may define another subgroup of autoimmune hepatitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Non-organ specific autoantibodies associated with chronic C virus hepatitis

Recently antibodies to hepatitis C virus were detected in sera of chronic active hepatitis patients, with anti-smooth muscle autoantibodies or with anti-liver/kidney microsomal type 1 autoantibodies. As the latter were used to differentiate autoimmune chronic active hepatitis from chronic non-A, non-B virus hepatitis, it was mainly important to discover if autoantibodies were associated with chronic hepatitis C virus infection. The sera of 272 chronic hepatitis C patients were screened by indirect immunofluorescence for non-organ specific autoantibodies. Antinuclear antibodies and anti-smooth muscle autoantibodies were more frequent in chronic hepatitis C patients than in blood donors (n = 100). Anti-liver/kidney microsomal type 1 autoantibodies were not detected in the sera of the blood donors, in the 74 hepatitis B patients or in the 30 alcoholic hepatitis or cirrhotic patients' sera tested as controls. They were detected in 14 chronic hepatitis C patients. These antibodies were compared in immunodiffusion to anti-liver/kidney microsomal type 1 autoantibodies sera obtained from type-2 autoimmune chronic active hepatitis patients and an identity reaction was observed. Chronic hepatitis C patients without or with anti-liver/kidney microsomal type 1 autoantibodies, did not differ in age, sex ratio, transaminases and gammaglobulin level, risk factors for hepatitis C virus infection, association with other autoimmune diseases. These patients differed significantly from type-2 autoimmune chronic active hepatitis patients. We conclude that: (i) in some chronic hepatitis C patients the pattern and the titer of autoantibodies may create confusion with an autoimmune chronic active hepatitis; (ii) There is no serological evidence for a hepatitis C virus infection in true type-2 autoimmune chronic active hepatitis.

Anti-LKM-1 antibodies determined by use of recombinant P450 2D6 in ELISA and western blot and their association with anti-HCV and HCV-RNA

Several subtypes of anti-liver-kidney microsome antibodies (LKM) are known. LKM-1 antibodies associated with autoimmune chronic active hepatitis recognize P450 2D6, a cytochrome P450 mono-oxygenase. The frequent association of anti-LKM-1 antibodies and hepatitis C virus (HCV) infections and the probable existence of an infectious and autoimmune form of anti-LKM-1-associated hepatitis, requiring different therapeutical strategies, necessitates the exact determination of anti-LKM-1 specificities. Therefore, we compared various antibody tests (immunofluorescence, ELISA with recombinant P450 2D6, and Western blot with recombinant and natural antigens and agargel double diffusion) with sera of 27 anti-LKM-1-positive chronic active hepatitis (CAH) patients, with 61 sera harbouring anti-mitochondrial antibodies, 100 sera each from HCV-RNA-positive and HCV-RNA-negative patients, and 50 sera of healthy persons. Western blot techniques using recombinant MS2-polymerase P450 2D6 fusion protein were found to be the most sensitive and specific method for anti-LKM-1 antibody determination in routine laboratory. The recently recognized association of anti-LKM-1 antibody and HCV infection was confirmed by the results of this study. In anti-HCV and HCV-RNA-positive patients with anti-LKM-1 antibodies there was a preponderance of males with higher mean age and lower antibody titres. The results support the hypothesis of the existence of an autoimmune as well as an infectious (HCV triggered) subgroup of anti-LKM-1-positive hepatitis.