The presence of non-organ-specific autoantibodies is associated with a negative response to combination therapy with interferon and ribavirin for chronic hepatitis C

Various immunological phenomena have been described in patients being exposed to the hepatitis C virus (HCV) [1]. Organ-specific and non-organ-specific autoantibodies are found in a considerable number of patients with acute and chronic hepatitis C [2]. Especially the high percentage of non-organ-specific autoantibodies (NOSA) in chronic infection has led to further investigation of the potential biological relevance of these findings. In recent studies the prevalence of different NOSA, including anti-nuclear antibodies (ANA), anti-smooth muscle antibodies (SMA), anti-mitochondrial antibodies (AMA), anti-neutophil-cytoplasmatic antibodies (ANCA), and anti-liver/kidney micosomal antibodies (LKM) were investigated before, during and after monotherapy with interferon-α for chronic hepatitis C [3, 4]. However, there is little information on NOSA prevalence in patients treated with current standard therapy, i.e. the combination of interferon-α and ribavirin. This should be investigated, as ribavirin has been demonstrated to have distinct immunomodulatory effects [5, 6]. Furthermore, the former analyses of the influence of NOSA on the clearance of the hepatitis C virus upon monotherapy with interferon-α are controversial, with a few studies showing a tendency to a poorer treatment response in autoantibody-positive subjects while other investigations could not demonstrate any difference in the efficacy of therapy [3, 7, 8]. However, there are no studies so far that investigated the relevance of NOSA with regards to the virological and biochemical response in patients treated with interferon-α plus ribavirin. This combination therapy now represents the treatment of choice since it has been proven to be superior to interferon monotherapy in large randomised trials [9].

The aim of the present study was to determine the prevalence of NOSA in patients positive for anti-HCV antibodies and to systematically analyse the potential impact of these antibodies on the efficacy of a combined antiviral therapy with interferon-α and ribavirin in patients with chronic hepatitis C infection.

The nucleoside analogue ribavirin has been demonstrated to increase the efficacy of antiviral treatment for hepatitis C when used in combination with interferon-α [9]. As the role of the balance between Th1- and Th2-associated cytokines has been shown to be of primary importance in antiviral therapy [14], the superiority of the current standard treatment might be partly attributed to the immunomodulatory properties of ribavirin [5, 6, 15]. The aim of our study was to assess whether such properties of ribavirin could unmask clinical differences with relation to the presence of autoantibodies in patients with hepatitis C. Therefore, we first determined the prevalence of NOSA in a cohort of 78 anti-HCV positive patients. In our study, a total of 46.2% of subjects had at least one NOSA, with ANA and SMA showing the highest prevalence rates (19.2% and 32.0%, respectively). The prevalence of NOSA in our patients is comparable to previous studies [2, 16], which demonstrated these antibodies to be present at similar frequencies. AMA and ANCA have been rarely found in patients with hepatitis C [17, 18], which was confirmed in our cohort of patients. In contrast to other investigations [16, 19], LKM antibodies were not detected in our patients, most likely due to the sample size and the cut-off for positivity of immunofluorescence (reactivity at serum dilution ≥ 1: 40) in our study. The analysis of ANA and SMA subspecificities revealed that the vast majority of these autoantibodies in our study subjects were ANA with a speckled pattern and SMA with a vessel wall staining pattern, which is in line with earlier findings [7, 16, 20]. In these former studies positivity for NOSA was associated with distinct clinical and laboratory variables. Cassani et al. [7] found an association between NOSA (mostly ANA and SMA) and female gender, AST and AST values as well as with necro-inflammatory activity in liver biopsies. The correlation between ALT and the presence of NOSA could be reproduced in our series, but there was no association between the presence of NOSA and either gender or grade of portal necro-inflammation in liver specimens. The latter differences are likely due to the different sizes of the study populations, as other smaller studies could also not confirm a close relationship between NOSA and gender or liver histology [16, 21]. Interestingly, despite a considerable overlap between groups, the association of ALT values with positive NOSA seems to be reproducible throughout different studies [7, 22].

The clinically most important finding of our study is the different efficacy of antiviral therapy with ribavirin and interferon-α in patients without NOSA as compared to subjects tested positive for NOSA. Absence of NOSA prior to and during the combination therapy was associated with a highly favourable treatment response with an odds ratio of 4.65 (95% CI 1.31 – 16.48). This association held true after adjustments for HCV genotypes and HCV-RNA levels in logistic regression analysis. Since we focused on immunological parameters in a small cohort of patients, a positive treatment response was initially defined as any negative HCV-RNA throughout the course of the study. However, there was no subject with a viral breakthrough and only four patients relapsed after completion of the therapy (two with NOSA, two without NOSA). The re-analysis with inclusion of the latter patients does support our major conclusions (OR 6.46, 95% CI 1.54 – 27.19).

These results differ from other studies that could not find an association between presence of NOSA and efficacy of antiviral therapy [8, 23]. However, the former studies employed interferon monotherapy, whereas combination therapy (interferon-α plus ribavirin) was used in our patients only. Furthermore, in two studies [3, 7], including the one with the highest number of patients (n = 144) [7], a trend towards a poorer response to therapy in patients with autoantibodies was already noted. In both studies this trend just failed the 95%-level of statistical significance.

Why should the addition of ribavirin to antiviral therapy make a difference? In view of our data and published results [7, 16, 19, 20, 22] the presence of autoantibodies can be interpreted as a marker for a non-specific activation of mononuclear cells in response to infection with the hepatitis C virus. This might be associated with an attenuation of the specific immune response and consecutive failure to clear the virus in a number of patients. This hypothesis is supported by our finding that patients with NOSA have a higher viral load compared to subjects without autoantibodies. As ribavirin has distinct immunomodulatory properties, the addition of this agent to the therapy might modulate the balance between a specific antiviral and a non-specific immune response in selected patients. Therefore, despite the overall benefits of ribavirin, the addition of this immunomodulatory drug to the therapy could unmask individual differences in the immune balance (Th1 versus Th2) with regards to antiviral treatment, which were not obvious in studies investigating interferon monotherapy only. In accordance to these findings, a recent study could demonstrate that the addition of ribavirin to interferon monotherapy does not modify the thyroid autoantibody pattern but increases the risk to develop hypothyroidism, which was significantly associated with long-term remission [24]. It is important to note that safe and efficacious therapy is still lacking for patients with hepatitis C and (auto)immune abnormalities and that it is mandatory to be aware of the potentially life-threatening autoimmune reaction in patients with chronic hepatitis C and positive NOSA during interferon therapy. Therefore, further studies with larger numbers of patients are needed to confirm the clinical relevance of our findings.

Our observations are related to the immunopathological discrimination between chronic hepatitis C, autoimmune hepatitis, and the "hepatitis C-autoimmune-overlap syndrome". In our study, we employed the revised scoring system for the diagnosis of autoimmune hepatitis in order to exclude a predominant autoimmune liver disease with sufficient specificity and sensitivity [10, 25]. Furthermore, only one of our patients had low titer SMA without vessel wall staining pattern and none had ANA with homogeneous staining pattern or LKM antibodies, which are closely correlated to autoimmune hepatitis [26]. Nevertheless, there are clinical presentations with mixed or atypical features because exclusive viral and autoimmune disorders only represent the two ends of the diagnostic spectrum [27]. Therefore, in the light of our and previous studies, NOSA might be determined in order to further stratify patients with chronic hepatitis C and (auto)immune abnormalities.

In this study, we were able to demonstrate a negative relationship between the efficacy of a combined antiviral treatment with interferon-α plus ribavirin for chronic hepatitis C and the presence of non-organ-specific autoantibodies in univariate and multivariate analyses. However, studies in a larger number of patients should be performed before generalising our findings with regards to treatment decisions. Furthermore, future studies should include the measurement of peripheral immune parameters, i.e. cytokines and monocyte activation markers, as well as genetic studies in order to elucidate the pathophysiological association between the presence of autoantibodies and a reduced efficacy of combined antiviral treatment with interferon-α and ribavirin.