Therapeutic vaccination in the immunotolerant phase of children with chronic hepatitis B infection

Aim. Hepatitis B virus (HBV) infection is a major global health concern and is the most common cause of chronic liver disease worldwide. Our aim was to investigate the efficacy of specific HBV vaccination as active immunotherapy in treating chronic hepatitis B (CHB) infection during the immunotolerant phase of children with normal aminotransferase values and high viral load. Materials and methods. Seventy-four patients never vaccinated before were randomly and prospectively recruited into two groups. Group 1 included 43 patients vaccinated with three standard injections of the GenHevac B vaccine at 30-day intervals. Group 2 contained 31 patients who did not receive any medication or vaccination (control group). Postvaccination serologic and virologic evaluation was performed 6 months after the first injection and at the end of the 12th month. Response to therapy was defined as loss of HBV DNA in serum and hepatitis B e antigen (HBeAg) seroconversion (loss of HBeAg), development of hepatitis B e antibody (anti-HBe). Results. The mean baseline alanine aminotransferase (ALT) value in Group 1 was 33.0 ± 9.6 IU/1 ,34.6 ± 13.9 IU/1 at 6 months after first injection and 34.3 ± 17.1 IU/1 at end of 12 months (P > 0.05). In Group 1 the HBV DNA load at the start of immunization was 3571 ± 1292 pg/ml; this value was 3220 ± 1217 pg/ml at the 6th month and 2931 ± 1292 pg/ml at the 12th month (P > 0.05). In Group 2 the mean ALT values at the beginning of therapy and at the 6th and 12th months were 32.6 ± 7.8, 32.3 ± 8.0 and 30.3 ± 7.3 IU/1, respectively (P > 0.05), and the mean viral load HBV DNA values were 3909 ± 1378, 3546 ± 869 and 3106 ± 718 pg/ml, respectively (P > 0.05). There was no statistically significant difference between Group 1 and Group 2 at the end of the 6th and 12th months in the mean ALT values and mean viral load of HBV DNA (P > 0.05). Except for one patient in each group, hepatitis B surface antigen and HBeAg clearance or hepatitis B surface antibody and anti-HBe seroconversion were not observed during follow-up (P > 0.05). Conclusion. In this multicentered study comparison of vaccinated and unvaccinated groups of immunotolerant children with CHB infection showed no difference in the clearance of HBV DNA or seroconversion from HBeAg to anti-HBe. Different immunization protocols should be considered for future investigations in the immunotolerant phase of children with CHB infection.