[Evaluation of serum IgG, IgA and IgM levels as indicators of hepatic fibrosis in patients with chronic hepatitis C infection].

The prediction of development of hepatic fibrosis is of crucial importance in terms of disease monitorization and treatment follow-up of patients with chronic hepatitis C virus (HCV) infections. Liver biopsy which is an invasive and complicated method, still remains as the gold standard method for the diagnosis of liver fibrosis. Recently, non-invasive diagnostic tests to determine the biological markers of liver fibrosis have been developed as a possible alternative to liver biopsy. The aim of this study was to evaluate the levels of serum IgG, IgA and IgM antibodies as possible indicators for hepatic fibrosis among patients with chronic HCV infection. A total of 57 patients (35 female, 22 male; mean age: 51 ± 8.9 years) who were followed-up between January 2007-November 2008, were enrolled in the study. All of the patients were positive for serum anti-HCV and HCV-RNA, while none of them were under antiviral therapy for the last six months. The patients were hospitalized for liver biopsy and biopsy samples were evaluated according to Modified Knodell Histological Activity Index. Forty-nine patients with no liver fibrosis or low to moderate fibrosis were classified as Group 1 (stage 0, 1, 2, 3) and eight patients with high to severe fibrosis were classified as Group 2 (stage 4, 5, 6). Serum IgG, IgA and IgM levels of the patients were determined by a commercial immunonephelometric method (Dade Behring, Germany). Increased antibody levels were detected in a total of 61.4% (35/57) of patients, of which 28 (49.1%) yielded high IgG, 5 (8.8%) yielded high IgM and 2 (3.5%) yielded high IgA levels. The mean IgG levels of patients in Group 1 and 2 were 16.3 ± 4.6 and 21.8 ± 5.2 g/L; mean IgM levels were 1.3 ± 0.6 and 1.6 ± 0.8, and median IgA levels were 2.0 (0.5-5.3) and 3.3 (1.3- 4.3) g/L, respectively. IgG and IgA levels of patients from Group 2 were found significantly higher than those patients from Group 1 (p= 0.003, p= 0.03, respectively), however there was no significant difference between the groups with respect to serum IgM levels (p= 0.311). When the patient groups were also evaluated in terms of other parameters, no statistically significant differences were detected for ALT, AST, HCV-RNA levels and mean ages (p= 0.95, p= 0.21, p= 0.73, p= 0.10, respectively), however, anti-HCV levels were found significantly higher in Group 2 (p= 0.043). The data of this study indicated a significant relationship between the levels of serum IgG, IgA and the severity of hepatic fibrosis among patients with chronic HCV infection. It was concluded that high serum IgG and IgA levels may be helpful indicators together with the other non-invasive markers for the prediction of liver fibrosis in case when liver biopsy could not be performed.