Viral genotypes as determinants of autoimmune expression in chronic hepatitis C

Progress in hepatitis C genotyping and its clinical significance

There has been a growing number of hepatitis C cases in China. The progress of hepatitis C infection is prone to be chronic, which leads to high incidence of liver cirrhosis and hepatocarcinoma. It has been reported that high variation of hepatitis C virus is correlated with its route of transmission, geographical and clinical distribution, progression and outcome of disease. So this article provides a brief review on aspects of hepatitis C genotyping and clinical significance of the progress.

Autoantibodies and hepatitis C virus genotypes in chronic hepatitis C patients in Estonia

AIM: To determine the prevalence of several autoantibodies in chronic hepatitis C patients, and to find out whether the pattern of autoantibodies was associated with hepatitis C virus (HCV) genotypes.

METHODS: Sera from 90 consecutive patients with chronic hepatitis C were investigated on the presence of anti-nuclear (ANA), anti-mitochondrial (AMA), anti-smooth muscle (SMA), anti-liver-kidney microsomal type 1 (LKMA1), anti-parietal cell (PCA), anti-thyroid microsomal (TMA), and anti-reticulin (ARA) autoantibodies. The autoantibodies were identified by indirect immunofluorescence. HCV genotypes were determined by a restriction fragment length polymorphism analysis of the amplified 5’ noncoding genome region.

RESULTS: Forty-six (51.1%) patients were positive for at least one autoantibody. Various antibodies were presented as follows: ANA in 13 (14.4%) patients, SMA in 39 (43.3%), TMA in 2 (2.2%), and ARA in 1 (1.1%) patients. In 9 cases, sera were positive for two autoantibodies (ANA and SMA). AMA, PCA and LKMA1 were not detected in the observed sera. HCV genotypes were distributed as follows: 1b in 66 (73.3%) patients, 3a in 18 (20.0%), and 2a in 6 (6.7%) patients.

CONCLUSION: A high prevalence of ANA and SMA can be found in chronic hepatitis C patients. Autoantibodies are present at low titre (1:10) in most of the cases. Distribution of the autoantibodies show no differences in the sex groups and between patients infected with different HCV genotypes.

Hepatitis C-associated arthritis

Rheumatologic complications of hepatitis C virus (HCV) infection are common and include mixed cryoglobulinemia, vasculitis, sicca symptoms, myalgia, arthritis, and fibromyalgia. The prevalence of cryoglobulinemia in Sweden and Germany is much lower compared with data from southern Europe. Viral, genetic, or environmental factors may be responsible for such a difference in prevalence. There is no single clinical picture of arthritis in patients with HCV infection. There is a well-defined picture of arthritis associated with the presence of mixed cryoglobulinemia that consists of an intermittent mono- or oligoarticular, nondestructive arthritis affecting large and medium-size joints. Involvement of salivary and lacrimal glands is common in HCV-infected subjects, but HCV antigens are not detected in affected glands. HCV-infected subjects express a high prevalence of a variety of autoantibodies, usually in low titers. The clinical significance of most of these autoantibodies is not clear. The prevalence and titer of these autoantibodies are unaffected by interferon-alpha therapy. Several studies have attempted to assess whether HCV infection may be involved in the etiopathogenesis of rheumatic and autoimmune diseases. The results of most of these studies do not support the idea that HCV infection may play a pathogenic role in the development of systemic lupus erythematosus, antiphospholipid syndrome, or leukocytoclastic vasculitis. Experience treating patients with HCV-associated arthritis is limited and treatment remains controversial. No major therapeutic trials in HCV-associated arthritis were reported in the past 2 years.

Autoimmune liver disease

Regional differences in the manifestations of autoimmune hepatitis underscore the importance of genetic and/or environmental factors in its expression. The -308 polymorphism of TNF-A increases susceptibility to type 1 autoimmune hepatitis; HLA DRB1*13 is an important risk factor in South America; and DRB1*07 characterizes type 2 autoimmune hepatitis. Minocycline and mesalazine can trigger the disease, and interferon therapy can accentuate autoimmune manifestations. Autoimmune cholangitis in Japan is similar to primary biliary cirrhosis, and assays for carbonic anhydrase II lack diagnostic specificity. Perinuclear antineutrophil cytoplasmic antibodies are reactive to diverse nuclear antigens, but high mobility nonhistone chromosomal proteins may be important targets in autoimmune hepatitis. T cells can cross-react with viral and host peptides, and the candidacy of glutathione S-transferases as target autoantigens has been weakened. A murine model of PBC will be useful in studying mechanisms of autoreactivity, and cyclosporine has shown promise in the treatment of children with autoimmune hepatitis. Recurrence after liver transplantation is common, and it may require retransplantation. The human transplantation model will be valuable in understanding the host-and organ-specific contributions to disease expression.