Hepatitis B vaccination in patients receiving antiviral monotherapy after liver transplantation for chronic hepatitis B

Abstract

INTRODUCTION: Life long antiviral prophylaxis is required for patients who are transplanted for hepatitis B (HBV). Our study aimed to determine if a double-dose pre-S containing HBV vaccination (Sci-B-VacTM) could elicit an adequate and sustainable immune response in HBV patients who developed previous hepatitis B surface antibody (Anti-HBs) response after liver transplantation (LT). METHOD: All patients who were transplanted for HBV related disease for >1 year with normal graft function and hepatitis B surface antigen (HBsAg) seronegativity were evaluated. They were recruited to receive a 40mcg pre-S containing HBV vaccine if they were responders in our previous vaccine trial, or anti-HBs was positive for >1 year after LT or a peak anti-HBs at any time point after LT was >100mIU/ml. All patients received oral antiviral therapy as prophylaxis, none of them had hepatitis B immunoglobulin (HBIG) at any time point before or after LT. Primary endpoint was the development of anti-HBs ≥10mIU/ml from previous negative value or a 1-log increase from baseline. Anti-HBs up to 32 months after vaccination was monitored. RESULTS: Eighty-six patients were recruited; 5 were responders from previous trial; 45 patients had detectable anti-HBs >1 year after LT and 36 patients had an anti-HBs >100mIU/ml. Figure 1 showed the anti-HBs response of all responders. All (5/5,100%) previous responders responded to booster vaccination and all demonstrated a positive response 2 weeks after vaccination with median anti-HBs of 638 (range 146-1000)mIU/ml. Anti-HBs remained detectable in all patients at 32 months follow-up. For the remaining 81 patients, 10/81 (12.3%) responded. Table 1 showed the characteristics between responders and nonresponders in the 81 patients. Majority (8/10, 80%) of them developed a positive response at 2 weeks after vaccination; the remaining 2 patients responded at 1 month and 3 months after vaccination. At 32 months after vaccination, anti-HBs remained detectable in 3/10 (30%) patients. CONCLUSION: All previous responders responded to booster vaccination, implying durability and memory of HBV immune response, which is an important prerequisite for definitive host immunity for HBV. In patients who had spontaneous and significant anti-HBs production after LT, a single HBV vaccination can induce response in 12.3% of patients which was higher than that reported in literature. The fact that none of our recipient received HBIG, and anti-HBs persisted up to 32 months in 8 patients after vaccination, demonstrating a spontaneous production of anti-HBs which is independent of adoptive immunity transfer from donor and passive immunity. This group of patients might be potential target for anti-viral prophylaxis withdrawal.