Serum immunoglobulins in patients with chronic hepatitis C: A surrogate marker of disease severity and treatment outcome

Background/Aims: Moderate polyclonal hypergammaglobulinemia is a common finding in chronic viral liver disease; however, its clinical significance has not been completely elucidated. We attempted to determine whether serum immunoglobulin levels were correlated with the disease severity and the treatment outcome in patients with chronic hepatitis C. Methodology: In a total of 102 patients with chronic hepatitis C, we performed serum tests on immunoglobulins and determined the histology activity index (HAI) score by liver biopsy. In 97 patients, immunoglobulin levels were followed prior to and 6 months after interferon (IFN) therapy. Results: Serum gamma (y)-globulin and immunoglobulin (IgG) were well correlated with HAI score (both; p < 0.0001), grading score (both; p < 0.01), and staging score (both; p < 0.0001). Among the 97 patients who received 6 months of IFN monotherapy, 31, 29, and 37 patients were complete, transient and non-responders, respectively. In the three subgroups, a significant difference was found in histological HAI, grading, and staging scores (p < 0.01, p < 0.05 and p < 0.0001, respectively), and in serum levels of y-globulin and IgG (both; p < 0.0001). Following IFN treatment, serum y-globulin and IgG were significantly decreased in the complete responders (both; p < 0.0001). Furthermore, serum levels of y-globulin and IgG of 1.5g/dL were useful for predicting the treatment outcome of IFN monotherapy. Conclusions: The measurement of serum y-globulin and IgG is a valuable non-invasive tool for assessing the disease severity and treatment outcome in patients with chronic hepatitis C.