Viruses and auto-immune hepatitis

Herpesvirus DNA is frequently detected in liver tissue from hepatitis C patients

BACKGROUND AND AIMS

Herpesviruses infect the liver and cause minor hepatitis. Our aim is to verify the presence of herpesviruses in the liver from hepatitis C patients and the possible influence of these viruses in the liver disease.

METHODS

We searched for herpesvirus DNA in liver biopsies from patients with hepatitis C and from a control group without hepatitis by means of nested polymerase chain reaction. Serological investigations were carried out as well.

RESULTS

Thirty-four liver specimens from hepatitis C patients were examined, 12 of which (35.3%) were positive for at least one herpesvirus DNA, whereas among the 19 control specimens only two were positive (10.5%; P = 0.049). Liver biopsies from seven patients, three with acute hepatitis of unknown origin, three with non-alcoholic steatohepatitis and one with autoimmune hepatitis were also investigated and three positive samples were found.

CONCLUSIONS

The prevalence of herpesvirus DNA was found higher in patients with hepatitis C than in individuals without hepatitis. The influence of herpesviruses on the clinical course of hepatitis C is considered.

Pathogenesis of primary biliary cirrhosis, primary sclerosing cholangitis, and autoimmune cholangiopathy

Autoimmune liver diseases have much in common with each other, and there are clear associations with genetic haplotypes. Elegant studies have shown autoimmune liver disease induced by viruses and drugs. Although there is evidence for nonimmunological events precipitating immune disease, especially in primary sclerosing cholangitis, the precise pathways, what is bystander and what is essential, have not been determined. This article reviews some of the mechanisms involved in pathogenesis.

Sjögren's syndrome associated with autoimmune hepatitis. A case report

Liver involvement in patients with primary Sjögren's syndrome is rare, usually without clinical significance and histologically characterized by a feature like stage 1 primary biliary cirrhosis. We describe herein a case of acute and severe autoimmune hepatitis in a patient suffering from primary Sjögren's syndrome. The diagnosis of Sjögren's syndrome was performed in 1989. In June 1995 the patient presented severe weakness, jaundice and elevation of transaminases; moreover IgG raised to 5560 mg/dl and ANA titre increased to 1:20480. The patient denied alcohol and drug use and a viral hepatitis was excluded. Antimitochondrial antibodies, anti-smooth muscle antibodies and antibodies against liver kidney microsomes were negative. An abdomen ultrasound examination revealed hepatomegaly, with irregular echogenic structure and lymphoadenomegaly near the celiac tripod. Liver biopsy demonstrated a picture of autoimmune hepatitis. The patient was treated with prednisone 50 mg/day and azathioprine 50 mg/day, with improvement in clinical and liver function indices. At present, the patient is given only 10 mg/day of prednisone. The association of Sjögren's syndrome with autoimmune hepatitis is very rare: in the literature only one other similar case has been reported.

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.

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.

Viruses, virulence and pathogenicity

Pathogenicity is a complex process with stringent requirements of both the host cell and the infecting virion. Among these requirements are a port of entry into host cells, a means of replication for the virus, and a means by which infection damages host cells. Damage to the host can result from multiple mechanisms including transformation, suppression of cellular metabolism, apoptosis, autoimmune responses directed against infected or uninfected tissues, or by molecular mimicry. In the attempt to identify new associations between viral infection and disease, investigators should be mindful that variable host factors as well as viral infection may be required for pathogenesis. Efforts to associate specific viral infections with specific diseases may be obscured by final common pathways through which multiple agents damage host cells in similar ways.

Hepatitis C: progress and problems

The hepatitis C virus (HCV), a single-stranded RNA virus, is the major cause of posttransfusion hepatitis. HCV isolates differ in nucleotide and amino acid sequences. Nucleotide changes are concentrated in hypervariable regions and may be related to immune selection. In most immunocompetent persons, HCV infection is diagnosed serologically, using antigens from conserved regions. Amplification of RNA may be necessary to detect infection in immunosuppressed patients. Transmission by known parenteral routes is frequent; other means of spread are less common and may represent inapparent, percutaneous dissemination. Infection can lead to classical acute hepatitis, but most infected persons have no history of acute disease. Once infected, most individuals apparently remain carriers of the virus, with varying degrees of hepatocyte damage and fibrosis ensuing. Chronic hepatitis may lead to cirrhosis and hepatocellular carcinoma. However, disease progression varies widely, from less than 2 years to cirrhosis in some patients to more than 30 years with only chronic hepatitis in others. Determinants important in deciding outcome are unknown. Alpha interferon, which results in sustained remission in selected patients, is the only available therapy. Long-term benefits from such therapy have not been demonstrated. Prevention of HCV infection by vaccination is likely to be challenging if ongoing viral mutation results in escape from neutralization and clearance.

Hepatitis C virus chronic infection as a common cause of mixed cryoglobulinaemia and autoimmune liver disease

OBJECTIVES

Mixed cryoglobulinaemia (MC) and autoimmune chronic hepatitis (AI-CH) are frequently associated with hepatitis C virus (HCV) chronic infection. Because HCV represents a possible common aetiological factor, the aim of the present study is to investigate the clinico-serological alterations of both MC and AI-CH and to verify a possible overlap between these disorders.

SETTING

Patients from three tertiary referral centres.

SUBJECTS

Two Italian series of 88 MC patients and 30 AI-CH type 1 were studied.

RESULTS

MC and AI-CH share several clinico-serological features. The patients' mean age (MC vs. AI-CH: 60 +/- 9 vs. 57 +/- 13 years), disease duration (10.5 +/- 5 vs. 9.6 +/- 6 years), and female/male ratio (3.4 vs. 3.3) were very similar in the two series. Typical hallmarks of MC, i.e. purpura, arthralgias, and weakness, circulating mixed cryoglobulins with rheumatoid factor activity, and hypocomplementemia were also recorded in a significant number of AI-CH patients. Similarly, chronic active hepatitis was found in 68% of MC patients and its histological and serological alterations were comparable with those of AI-CH; moreover, amongst various autoantibodies, antinuclear antibodies and/or anti-smooth-muscle antibodies were detected in half of the cases of MC. Anti-HCV antibodies, detected by second-generation Chiron ELISA and RIBA, were present in a high percentage of both MC and AI-CH (94 vs. 80%), and frequently associated with HCV viraemia (86 vs. 77%). Finally, anti-GOR, the HCV-related autoantibodies, were found in half cases of MC and AI-CH.

CONCLUSIONS

On the whole, these data suggest that HCV in combination with other infectious and environmental and genetic factors can trigger a complex immunological disorder with different clinical patterns.