Immune response during immunoclearance phase of Chinese patients with HBV genotypes B and C

Abstract

Background: Chronic hepatitis B patients with genotype B achieve HBeAg seroconversion at an earlier age compared with those with genotype C (Yuen et al., Hepatology 2003). Whether this is due to differences in tile immune response to file hepatitis B virus during the imrnunoclearance phase between patients with genotypes B and C has never been studied. Aims: To compare the immune response during the immunoclearance phase of patients with genotypes B and C. Patients and Methods: 20 HBeAg-positive patients with elevated ALT levels, 10 with genotype B and 10 with genotype C, were recruited. Proliferation and Till and Th2 immune responses of peripheral blood mononuclear cells were measured by 3H-thymidine uptake and ELISPOT assays respectively. The core promoter and precore mutations and HBV DNA levels were determined. Results: The followings are the interim results of first 12 patients (4 and 8 with genotypes B and C respectively). P values were not calculated because of the anlall number of patients. There were no differences in ALT and HBV DNA levels between two groups. Four patients with genotype B and 4 patients with genotype C had precore and core promoter mutations respectively. Compared to patients with genotype C, patients with genotype B had a higher stimulation index (proliferative response) towards HBcAg (4.6 vs. 2.7 respectively) and HBeAg (1.9 vs. 1.6 respectively). The results of tile ELISPOT assays are listed in the table. Conclusions: Compared to patients with genotype B, patients with genotype C have a lower proliferative response and greater induction of IL-10 production towards HBcAg and HBeAg. These phenomena may explain the delayed HBeAg seroconversion in patients with genotype C.